SYSTEM AND METHOD FOR FORMATION AND PROCESSING OF HIGH PRESSURE DIE CAST METAL ARTICLES

Abstract

A system and method for formation and processing of pressurized die cast metal articles or components includes an injection or casting station in which a series of cast metal articles are formed within a series of dies by the introduction of a metal material into the dies. The dies are then moved to a retention area where the metal material is permitted to solidify to form the castings, after which the dies are opened and the castings removed therefrom, and subsequently are transferred to a short cycle solution heat treatment station. The castings are conveyed through the short cycle solution heat treatment station with the castings maintained within a series of fixtures to dimensionally support and stabilize the castings during solution heat treatment thereof. The castings thereafter are moved through a quenching chamber or station, with the castings further being held or retained in a fixtured, dimensionally stabilized alignment and/or orientation as the castings are subjected to a quenching operation to quench and cool the castings to a normalized or substantially cooled state.

Description

CROSS-REFERENCED TO RELATED APPLICATIONS

This application is related to U.S. Provisional Application No. 61/778,946, filed Mar. 13, 2013.

INCORPORATION BY REFERENCE

The entire contents of U.S. Provisional Application No. 61/778,946, filed Mar. 13, 2013, is hereby incorporated by reference as if presented herein in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to a system and method for casting metal components. In particular, the present invention is directed to a system and method for forming cast metal components using pressurized die casting processes and conducting heat treatment and quenching of such cast metal components with increased efficiency.

BACKGROUND OF THE INVENTION

In the field of metal casting, it is known to remove cast components from their dies after solidification of the casting, after which the cast component can be substantially cooled, such as by quenching, in still or moving air, or optionally in a quench tank. Thereafter, it is known to subject the castings to a heat treatment process as necessary to provide the desired metal properties necessary for the finished casting. It is also understood that the heat treatment of metal castings, especially once cooled to ambient or near ambient temperatures, typically requires a significant amount of time and energy in order to first raise the temperature of the casting up to a temperature sufficient for solution heat treatment, and thereafter to conduct the required solution heat treatment for a time sufficient to attain the desired heat treatment properties therefor. There thus is a continuing need for processes that reduce time required to perform required solution heat treatment of cast metal work pieces. In addition, in the past, such conventional solution heat treatment processes have generally been viewed as impractical for use in treating high pressure die cast components due to potential for blistering as bubbles formed in the castings can burst or rupture upon exposure to elevated temperatures generally required for solution heat treatment of such parts. While improvements in high pressure die casting have been made to reduce the pores created within the castings during formation, and thus reduce potential blistering effects, it has still been found to be impractical to subject such castings to conventional solution heat treatment processes due to elongation and instability of the castings at elevated temperatures generally necessary for such solution heat treatments.

SUMMARY OF THE INVENTION

Briefly described, the present invention generally relates to a system and method for the formation and processing of high pressure die cast metal articles or components, including short cycle solution heat treatment and quenching thereof. The castings generally are formed using a high pressure die casting process in which a molten metal material is injected into a series of dies. Thereafter, the dies are moved from their injection position to a retention area where they are retained for a desired time sufficient to enable solidification of the molten metal material therein sufficient to form the castings and thereafter subsequently subject the castings to solution heat treatment. It also can be understood by those skilled in the art that the formation of the castings can be accomplished using low pressure die casting processes followed by short cycle solution heat treatment and quenching, and/or aging as needed, according to the principles of the present invention.

Prior to solidification of the castings, or subsequent to a desired solidification and the removal of the castings from their dies, typically while the metal material thereof is still in a softened state, gating or feeder materials that remain attached to the castings from the injection of the molten metal material into the dies, can be removed or cut off from the castings. For example, punches or knives internally mounted within the dies can be actuated to engage and cut through the metal at the junction between such gating or feeder materials, and/or any risers or other sprue materials projecting from the castings, so as to cut off and/or remove such feeder or gating materials from the castings while the metal thereof is in a substantially soft or semi-molten state. Alternatively, the castings can be engaged by a cutting blade or other, similar mechanism after opening of the dies for cutting and trimming such feeder or gating material, and/or risers attached to the castings prior to the transfer of the castings through a heat treatment station. As a further alternative, the feeder or gating materials can remain attached to the castings so as to provide a support attached to the castings by which the castings can be engaged and manipulated by a transfer mechanism, such as a robotic arm or gripper, without the castings being directly engaged by such transfer mechanism.

The castings generally will be retained in their retention area for a time sufficient to enable the castings to solidify to an extent as needed to undergo solution heat treatment. The castings generally will be fed and/or passed through a short cycle solution heat treatment station with the castings being first fixtured so as to be located and supported in a dimensionally stable orientation and/or alignment for transport through the furnace chambers of the short cycle solution heat treatment station, and thereafter for passage into and through a quench station for quenching of the castings. The fixturing of the castings can include placing the castings, with or without their feeder or gating materials attached thereto, in a series of fixtures or carriers.

Such fixtures can include tight, close-toleranced or full profile fixtures in which the castings are substantially engaged and constrained along multiple sides or surfaces thereof. In another embodiment, loose or open-toleranced fixtures can receive and support the castings along selected areas or sides thereof, and can be provided with wide tolerances to enable greater variations in the sizes or configurations of the castings being processed, and/or which can further be adapted to locate or secure the castings in desired dimensionally stabilized orientations by engagement and support of the feeder or gating materials attached thereto. The fixtures further can include indexed fixtures wherein the castings are received within a carrier or first fixturing structure conveyed by the conveyance mechanism of the short cycle solution heat treatment station and/or downstream quench chamber/station. The first fixturing structures and the castings therein are engaged by secondary carriers or clamping fixtures, such as at selected points during the solution heat treatment and/or quenching of the castings, or which are moved into an engagement with and move the castings throughout their path of travel through the furnace chambers of the short cycle solution heat treatment station and/or downstream quenching station/chamber.

The fixtures further can be fixedly mounted to the conveyance mechanism moving through the short cycle solution heat treatment station and/or a downstream quench station/chamber, or can be independent, freely moveable carriers in which the castings are received and which transported with the castings, such as by being placed within the flights or between lugs of the conveyance mechanism of the short cycle solution heat treatment chamber and/or the quench station/chamber. Thus, the fixtures can be adapted to move with their associated castings throughout the entire short cycle solution heat treatment and quenching processes, and/or through a further downstream aging chamber as needed.

The short cycle solution heat treatment station can include a series of furnace chambers and/or a quench chamber arranged in series along the path of travel of the castings. The furnace chamber further can be divided into sub-chambers or stations, i.e., 4-8 stations, although more or fewer stations also can be used, at which castings are exposed to varying temperature levels or applications of heat. As the castings can enter the short cycle solution heat treatment station, they will be exposed to heated fluid flows, at temperatures that can exceed the solution heat treatment temperature of the metal of the castings for a time sufficient to rapidly raise the temperature of the castings up to a part process stabilization temperature for the metal thereof. Such a part process stabilization temperature (PPST) generally is a temperature at which the castings can be rapidly heated (i.e., within 10-15 minutes or less) to a temperature that is below the solution heat treatment temperature for the metal thereof, but at which the temperature of the castings generally flattens and/or levels off, and the rate at which the temperature increases slows such that it can potentially take as much, or even more time to heat the castings a remaining 50° C.-30° C. to the solution heat treatment temperature for the metal thereof. The temperature of the castings further can be monitored by sensors within the furnace chamber or within the fixtures themselves, and communicated to a system control to detect the approach of the temperature of the castings to their PPST.

Once the castings are detected or determined to have reached or are approaching their PPST (for example, after a desired time interval or based on monitored temperatures of the castings), the castings will be moved to a second or next indexed heating position or station along the furnace chamber. In such a position, the castings typically are out of a direct application of heat or high temperature fluid media thereto, but still are generally maintained within an elevated temperature environment, which temperatures can be up to and/or can slightly exceed the solution heat treatment temperature for the metal of the castings. The castings can be maintained in this secondary or next position for a further desired time, i.e., 5-10 minutes. Thereafter, the castings then will generally be passed to a further downstream heating zone or chamber, and/or through additional heating positions where the castings generally will be subjected to lowered temperatures, i.e., at or generally below the solution heat treatment temperature for the metal thereof. The castings can be moved and maintained through this downstream heating chamber or zone, passing through various heating positions or stations as needed, with the temperature of the castings generally being maintained substantially at or around the PPST therefor for an additional time, i.e., 5-15 minutes, as needed to accomplish the solution heat treatment of the castings, with the potential for blistering distortion from overheating of the castings due to exposure to higher temperatures as needed for fully raising the castings to their solution heat treatment temperature and subsequent solution heat treatment thereof, being substantially reduced.

In one embodiment, the short cycle solution heat treatment station can include a quench chamber directly inline with the furnace chamber thereof such that the castings can be conveyed within their fixtures in their dimensionally stabilized, fixtured orientation, into the quench chamber. As the castings move through the quench chamber/station, the castings will be substantially rapidly quenched within approximately 1-3 minutes, although longer times also can be used depending upon the size and/or materials of the castings.

Alternatively, the quench chamber can be provided as a separate station downstream from the furnace chamber(s) of the short cycle solution heat treatment station. In such an embodiment, the castings can be engaged and placed into the quench chamber article still contained within their fixtures, such that the fixture and castings together as a unit are placed into the quench chamber with the castings thus aligned in a desired, known orientation with X-Y-Z coordinates thereof in a fixed, desired alignment supported against distortion or warping during the rapid quenching thereof. The castings also can be removed from their fixtures and placed into additional fixtures mounted along a conveying system extending through the quench chamber/station to maintain the castings in their fixtured, dimensionally stabilized alignment/orientation for quenching. As a still further alternative, a transfer mechanism can be provided for transferring the castings to the quench chamber/station, which transfer mechanism can include a fixture or gripping device that holds the castings in a fixtured, known orientation while moving the castings through the quench chamber/station for quenching of the castings. After quenching, the castings can be transferred for collection and further processing, including transfer to an aging station as needed.

The quenching of the castings generally will be accomplished in a controlled, progressive quenching manner or operation, with the castings maintained in their dimensionally stabilized, fixtured alignments. As the castings enter the quench chamber/station, a cooling mist or spray of a fluid media, i.e., air, water, thermal oils, etc., can be applied substantially from all sides of the castings to initiate quenching of the castings. As the castings continue along their path of travel through the quench chamber/station, the quenching flows applied to the castings can be progressively increased to rapidly quench and cool the castings to approximately an ambient normalized/quenched temperature. The castings further can be subjected to additional quenching operations, such as being placed within a quench tank or subjected to further cooling fluid flows to complete the quenching of the castings as needed, and further to remove any interior core materials therein. By fixturing the castings during quenching, the castings can be rapidly quenched, with the potential for warping, twisting or other distortion of the castings generally being substantially minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of one embodiment of the system and method for pressurized die casting of metal components according to the principles of the present invention.

FIG. 2 is a schematic illustration of an additional embodiment of the system and method for pressurized die casting of metal components according to the principals of the present invention.

FIGS. 3A-3C are end views illustrating various embodiments of short cycle solution heat treatment furnace chambers for heat treatment of the pressurized die cast components.

FIG. 4 is a side view schematically illustrating another embodiment of a solution heat treatment chamber illustrating movement of castings therethrough engaged within indexed casting fixtures.

FIG. 5A is an end view schematically illustrating an additional embodiment of a quench chamber for quenching the castings.

FIG. 5B is an end view illustrating a progressive quench chamber and quenching operation for the castings.

FIG. 5C is an end view of the progressive quench chamber of FIG. 5B, illustrating an additional quenching operation after internal progressive cooling of the castings.

FIG. 6 is a graph illustrating the heating of the castings to their part process stabilization temperature and subsequent solution heat treatment according to the principles of the present invention.

Various features, advantages and aspects of the present invention further may be set forth or apparent from consideration of the following detailed description, when taken in conjunction with the accompanying drawings. Moreover, it will be understood that the accompanying drawings, which are included to provide a further understanding of the present disclosure, are incorporated in and constitute a part of this specification, illustrate various aspects, advantages and benefits of the present disclosure, and together with the detailed description, serve to explain the principles of the present disclosure. In addition, those skilled in the art will understand that, according to common practice, various features and drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present disclosure.

DESCRIPTION OF THE INVENTION

Referring now in greater detail to the drawings in which like numerals indicate like parts throughout the several views, FIGS. 1 and 2 schematically illustrate embodiments of the system 10/10′ and method for the formation and processing of pressurized die casting of metal components, including conducting short cycle solution heat treatment and quenching of the castings according to the principles of the present invention. The present system 10 generally is directed to the processing of cast metal components, including metal castings formed from aluminum, or various other metals and/or metal alloys thereof, typically using a high pressure die casting process in which a molten metal M is injected into a die under pressure. For example, a wheel, automobile chassis part or engine block, or various other types of metal castings C can be die formed, retained in an adjacent holding area where the temperature of the castings can be monitored and their cooling moderated and/or arrested to provide sufficient solidification for discharging the castings from their dies, and thereafter subjected to a short cycle solution heat treatment process and quenching to enable the formation, solution heat treatment, and quenching of pressurized die cast components, in an overall more efficient and faster integrated process while minimizing potential for bubbling, distortion and other defects to the castings during each operative step.

As generally illustrated in FIGS. 1-2, the castings C generally are formed at a pouring or die-casting station 11 of the present system 10/10′ utilizing a pressured die casting process, which generally can include a high pressure die casting process, in which a molten metal material M, such as a molten aluminum or other metal or metal alloy materials, is injected or otherwise introduced into each of a series of dies 13 under pressure. As FIGS. 1 and 2 further illustrate, each of the dies 13 generally can be formed with a multi-piece construction, for example including a first or stationary section 16 and a second or movable die section 17. A gate passage 18 or other, similar feature through which the molten metal is introduced into an interior cavity 19 of the die 13 generally will be connected to a flow passage 21 of an injector or shot sleeve 22 through which the molten metal is introduced into the die under pressure by a piston 23 movable along the shot sleeve or injector 22 in the direction of arrows 24/24′ as shown in FIGS. 1-2. An interior core 26, generally formed from a foundry granular material or other, similar material, such as a salt material, silica, zircon, etc., also can be provided within the internal cavity of the die, about which the casting C will be formed. However, the castings also can be formed without an internal core.

As indicated in FIGS. 1 and 2, the molten metal M is injected into the interior cavity 19 of the die 13 under pressure. For example, the molten metal M can be fed from a reservoir or storage area 27 (such as a heated caldron or other, similar device), through a conduit or pipeline 28 into the injector 22. The molten metal will be urged along the interior flow passage or channel 21 of the injector 22 by movement of the piston 23, so as to urge the metal within the injector through the gating passage 18 and into the interior chamber of the die, as will be understood by those skilled in the art. Actual injection pressures and flow velocities for the formation of the castings can vary depending upon the composition of the metal being cast and the type of castings being formed. As the metal is injected into the interior of the die, it generally will fill the cavity 19 to define the casting, and can further surround and substantially encapsulate an internal core 26 (such as formed from a salt or other granular material) if included therein.

The dies or molds used in the present high pressure die casting system generally will include permanent metal dies or molds, as indicated in the drawings. It will, however, further be understood that various embodiments of the present invention disclosed herein can be used for processing castings in precision sand type molds, semi-permanent molds, and/or investment casting molds, depending upon the application. Thus, for example, in some applications, the dies 13 can be replaced with two-piece or clam shell type metal or green sand molds depending upon the casting process or products being produced.

It also will be understood that while a high pressure die casting operation is generally shown as being carried out by the pouring or casting station 11, the present system can be used with either high or low pressure casting systems under which the molten metal can be supplied to each die 13 under varying injection pressures depending on the cast component being produced. For example, if the cast metal component is formed using a high pressure die casting process, the metal can be injected into the chamber of the dies at injection pressures of upwards of 10,000 psi or greater. Alternatively, other components such as wheels or other smaller components, which can range from 5 to 300 pounds or more, the metal can be injected into the dies at lower pressures, e.g., in a range from approximately 2 to 40-50 psi, although other, substantially varying pressures also can be used depending on the metal material being cast and the type of casting being made.

As illustrated in FIGS. 1 and 2, once the interior cavity 19 of each die 13 has been filled with the molten metal, the die generally will be moved transferred away from its injection position 15 in communication with the injector 22 and moved along a path of travel indicated by arrows 31 to an initial holding or retention area 32. As each die is moved to and is retained in the holding area, it generally will be monitored with a sensor or series of sensors indicated by 33A-C in FIGS. 1 and 2 so as to monitor the temperature of the castings. Such sensors 33A-C can be mounted along the path of travel 31 of the castings and dies and at the holding area 32 as shown in FIGS. 1-2.

In addition, the sensors further can be mounted within the dies, as indicated at 33W in FIG. 1, and function to monitor or determine the internal temperature of the castings within the dies and can communicate the monitored temperature information to a system control which can determine when the castings have cooled to a temperature wherein the castings will have cooled to a substantially solidified state sufficient to enable removal of the castings from their dies and for removal of gating or feeder materials G formed with the castings as indicated at 34 in FIG. 1, without causing deformation or otherwise affecting the castings. As indicated in FIGS. 1-2, such gating or feeder materials G generally will be formed by the residual metal material contained within the gate passage and/or injection passage 18 of the dies 13, and often can be substantial in size. Thus, in some cases, it can be desirable to remove such gating materials (as shown at 34 in FIG. 1) to avoid unnecessary expenditure of heat and time for additionally heat treating such gating materials with their castings.

The removal of the gating or feeding materials G from the castings can be accomplished, as illustrated at 34 in FIG. 1, by engaging the materials with a knife, rotary cutting blade or other, similar cutter after the castings have been removed from their dies. In addition, the removal of the gating or feeder materials G also can be performed while the castings remain within their dies, such as by use of punches or knives internally mounted within the dies and/or the control of variable flow openings between the injection or gating passage(s) 18 and interior cavity 19 of the die. After the dies have been moved to the retention area and before opening of the dies to remove the castings therefrom, the punches or knives can be actuated so as to sever or cut the gating materials adjacent the junction between the gating passage or passages 18 and the internal cavity 19 of the die while the metal material of the casting remains in a soft, semi-fluid condition. Once the casting has further cooled to a sufficient solidification temperature, the die can be opened and the casting and its severed gating or feeder materials or portions separately removed from the dies. The die then can be returned to the pouring station 11 for casting additional components, while the casting continues along its processing path 31 for solution heat treatment and quenching. The cut away gating or feeder materials can be collected for scrap or recycling/remelting for use in forming additional castings.

Alternatively, the gating or feeder materials G also can be left with the castings as indicated in FIG. 2, such as for smaller cast parts and/or thinner wall castings that potentially could be damaged or distorted by direct contact therewith upon release or removal from their dies. The gating or feeder materials G can be left with the castings to provide a connected area or portion that can be readily engaged and/or gripped by a transfer mechanism 36 for ease of movement of the castings without direct engagement thereof. The gating or feeder materials also can be used to locate the castings in a dimensionally stable position during subsequent solution heat treatment and quenching, such as in a fixture or along a flighted or lug conveyor.

As further indicated in FIGS. 1 and 2, during removal of the castings C from their dies, the temperature of the castings generally will continue to be monitored by sensors, such as shown at 33B, which communicate monitored temperature data to the system control, to determine/ensure that the castings have been sufficiently solidified as needed to undergo solution heat treatment without damaging the castings. If not, the castings can be maintained in the holding area 32 for an additional time as needed for such additional solidification, or can be transferred via the transfer mechanism 36, shown in one embodiment as a robotic arm 37, to an additional or auxiliary holding area or retention zone as needed. While the castings are maintained in the holding area or retention zone, their temperature can continue to be monitored, and once the castings are determined to be at a sufficient solidification temperature, the system control can initiate transfer of the castings to the solution heat treatment station 45, including the fixturing the castings for dimensionally locating and stabilizing the castings for solution heat treatment and quenching, and for further aging of the castings and removal of the gating or feeder materials therefrom as needed.

In addition, in one embodiment, while the castings are in the holding area 32 of/adjacent the casting station, including undergoing gating removal if needed, the temperature of the castings can be controlled by the application of heat as needed in order to arrest cooling of the castings at or above a desired intermediate, retention or furnace introduction temperature. One or more applicators 39 can be operated by the system control in response to the monitored temperature information provided by the sensors 33C to apply heat as needed for moderating and arresting the cooling of the castings during removal of the gating materials G. Such heat applicators 39 can include one or more nozzles that apply heated fluid flows, such as heated air, or alternatively, can include radiant or infrared heating mechanisms, which can be mounted at desired positions or locations with respect to the castings as the castings are engaged and held in the retention zone and/or moved by the transfer mechanism 36. Additionally, the transfer mechanism, such as a robot arm, also can include at least one heating device or applicator mounted along its length for applying heat as needed during engagement and movement of the castings.

The castings generally can be maintained in the retention area 32 until the castings are detected/determined to have a temperature that is at or above the desired, pre-determined intermediate, retention or furnace introduction temperature, although in other applications, the castings can be allowed to cool below this temperature and even substantially cool to around an ambient temperature prior to solution heat treatment. In general, the short cycle solution heat treatment temperature will be a temperature at which the metal of the castings will undergo solution heat treatment to achieve the desired solution heat treatment properties therefor within about 30-35 minutes or less. For some castings, the short cycle solution heat treatment temperature within the short cycle solution heat treatment station can range at temperatures from about 400°-600° C. or more, as needed to obtain the desired or necessary solution heat treatment properties of the castings within a cycle or residence time of each casting within the heat treatment furnace of about 30-40 minutes or less. Other lesser or greater short cycle solution heat treatment temperatures also can be used depending on the type, size and/or metal material of the castings being treated. Maintaining the castings at or above a desired furnace introduction temperature can assist in reducing initial heat-up time and/or the amount of heat required for accomplishing a rapid initial heat-up of the castings to a part process stabilization temperature (PPST) as discussed below.

The furnace introduction temperature for the castings generally can vary depending on the metal and size of the castings, and typically will be sufficiently below the solidification temperature of the metal of the castings to enable the desired and necessary solidification of the castings to an extent necessary to enable removal of the gating materials therefrom without damage or distortion of the castings, but will still be sufficiently above an ambient temperature so that the castings are not in a “cold” state or substantially cooled to an extent to require an increase in total solution heat treatment time of the castings to greater than the desired 30-35 minute short cycle solution heat treatment temperature time therefor. For example, the intermediate or retention temperature can range from about 5-15° C. to about 250° C. below the short cycle solution heat treatment temperature for the metal of the castings, although greater or lesser temperature differences also can be used. The heat applicators 39 of the retention area 32 thus can be controlled to apply heat to the castings as needed to arrest cooling and/or maintain the temperature of the castings at or above the furnace introduction temperature before the castings are released/transferred to the heat treatment station 45.

The retention area 32 also can be located adjacent or sufficiently close to the heat treatment station in a position to enable the castings to be fed directly into the furnace chamber 46 of the heat treatment station 45, and/or to further undergo additional re-heating as needed to bring the temperature of the castings close to their short cycle solution heat treatment temperature prior to introduction of the castings into the heat treatment station furnace chamber 46. This control of the temperature of the castings prior to heat treatment accordingly can help reduce/minimize the time required and potentially the amount of heat to heat the castings to a temperature sufficient to begin and thus complete the short cycle solution heat treatment of the castings as soon as possible upon introduction of each casting, and preferably limit the required residence time of the castings with the furnace chamber to less than about 30-40 minutes.

As shown in FIGS. 1-2, the castings generally will be moved from the retention area 32 directly to the short cycle solution heat treatment station 45, which is typically located adjacent or in close proximity to the retention area 32 for the castings following their removal from their respective dies. In a first embodiment of the heat treatment station 45 as shown in FIG. 1, the heat treatment station generally can include a series of chambers, including a heat treatment furnace chamber 46 and a quench chamber 47. A conveying mechanism or system 48 generally is indicated as extending through the chambers 46/47 of the heat treatment station 45 for conveying the castings along their path of travel, indicated by arrows 31, through the chambers of the heat treatment station for heat treatment and/or quenching of the castings. The conveying mechanism can include various types of conveyor systems such as a roller hearth, belted conveyor, chain conveyor, walking beam or other types of conveying systems as will be understood by those skilled in the art.

As indicated in FIGS. 1-2, a series of fixtures 50/50′ preferably will be provided for receiving and retaining/maintaining the castings in a dimensionally fixed, stabilized alignment supported against distortion as the castings are exposed to elevated temperatures and subsequently quenched/cooled during the operational steps of the casting formation and treatment process according to the principles of the present invention. The castings can be removed from their dies and transferred directly by the transfer mechanism 36 to the downstream heat treatment station 45, with the castings typically being placed within a fixture 50, which can be fixedly mounted to a conveying mechanism 48 and thus carried through a downstream heat treatment station 45 and/or through any subsequent quenching and/or aging stations as necessary as shown in FIG. 1; or alternatively, can be provided as separate component carriers 50′ adapted to be transported with and thus carry the castings along their path of travel 31 including during transfer of the castings between the retention area, heat treatment station/chamber and quench station/chamber, as shown in FIG. 2. Such separate, free-moving fixtures 50′, can thus provide an assigned or associated carrier for each casting that moves with its associated casting as the casting is placed and transferred through the heat treatment station and/or any subsequent treatment stations such as for quenching and/or aging. In a further alternative embodiment, as indicated in FIG. 3A, the castings also can be placed directly on the conveying mechanism, such as within a flight or bay of a flighted lug or conveyor, for movement of the castings through the heat treatment furnace in a loosely supported/fixtured arrangement.

The fixtures 50/50′ (FIGS. 1, 2 and 3B-3C) can comprise trays, baskets, brackets or other, similar holding mechanisms, including clamshell trays, boxes or other enclosed structures 50 in which the castings can be placed and secured in a substantially fixed, dimensionally stabilized and supported arrangement to help protect the castings and maintain their dimensional shape/configuration throughout the solution heat treatment and quenching operations of the present integrated process. The fixtures also can include or be part of a robotic arm or overhead carriage that holds the castings in a stabilized alignment while moving the castings through the furnace and/or quench chambers, as illustrated in FIGS. 5B-5C, which transfer mechanism 82, such as a robotic arm having a gripper/fixture 83, handles/manipulates the castings during quenching thereof. As indicated in FIGS. 1, 2 and 4, the fixtures 50/50′/50″ generally will be designed to approximate the configuration and/or size and shape of the castings so that the castings will be received and supported therein in a manner that provides dimensional stability to the castings to limit or minimize potential for casting elongation and/or distortion and to assure geometric casting accuracy as the castings are exposed to heat treatment and quenching operations.

In one embodiment of the fixtures, as shown in FIGS. 1 and 3B, the fixtures 50 comprise “tight” or close-toleranced, full position fixtures in which the castings C can be received and maintained in a generally tightly controlled or fixed alignment/location therein. Such tight fixtures generally can be configured to substantially match the profile or configuration of the castings being produced, and further can include an enclosure or top section or clamp 50A whereby the castings can be substantially engaged along multiple surfaces or portions thereof to prevent twisting, warping or other distortion of the castings as the castings are subjected to elevated temperatures for solution heat treatment and/or are later moved into a quenching environment in which the castings are subjected to a rapid cool down or quenching within one to three minutes.

The tight, full position fixtures 50 can be mounted on or fixed to the conveying mechanism 48 of the heat treatment station as shown in FIG. 1, or can be independent or free-moving fixtures/carriers, such as shown in FIG. 2, which receive the castings therein (with or without the gating or feeder materials having first been removed from the casting) and thereafter can stay with the castings throughout the integrated process as the castings are transferred and moved through the heat treatment furnace and subsequently transferred into a quench chamber for quenching of the castings. When mounted to the conveying system 48 of the heat treatment station 45, as shown in FIG. 1, the fixtures can be moved between several fixed locations or positions by the conveying mechanism 48.

As also illustrated in FIG. 1, such conveyor mounted fixtures 50 can be rerouted, after removal of the castings therefrom, either before or after quenching, back to the inlet area 52 of the heat treatment station 45 for continued reuse thereof. Thus, the fixtures 50 can be moved, such as indicated by dashed lines 42, through a bottom or lower portion 43 of the heat treatment station 45 back to the inlet area 52 to enable the fixtures to be quickly and substantially directly returned to the inlet area for loading with a next available casting. In addition, passing the fixtures 50 through the bottom of the heat treatment station can enable the fixtures to be subjected to residual heat from the heat treatment furnace chambers 46 of the heat treatment station 45 for preheating of the fixtures prior to receipt of the castings therein.

The castings additionally can be conveyed in a loose-fixtured arrangement, wherein the castings are not necessarily rigidly engaged and held in a tight or close-tolerance/full position fixture 51 as shown in FIG. 1. In such a loose fixture arrangement, the castings can be received and supported or loosely fixtured within flights or between lugs of the conveying mechanism 48, as indicated in FIG. 3A; or can be received in an open-toleranced or loose fixture 50′ having larger tolerances so as to engage the castings generally along limited points or areas thereof and/or can be capable of receiving a wide range of different configuration and/or size castings as generally shown in FIG. 2. Thereafter, the fixtures 50′, with their castings therein, can be placed on the conveying mechanism 48, such as between lugs or within a flight thereof, within the fixtures, and thus the castings therein, located in a known, fixed position for movement through the heat treatment furnace chamber 46 and/or through the quench chamber 47 (FIG. 1)/80 (FIG. 2), and possibly through a further aging chamber 90 as needed. However, while FIG. 2 shows each casting loaded directly into a fixture 50′ by the transfer mechanism 36 (e.g., robot 37) at the retention area 32 of the casting station following removal of the castings from their dies, it will be understood that such a fixture also can be mounted directly on the conveying mechanism 48 of the heat treatment station. As also shown in FIG. 2, if the gating or feeder materials G are left with the castings for handling, the castings can be loosely fixtured by being placed within the loose fixture 50′, with their gating or feeder materials being engaged and held, such as within a slotted section 50 of the fixture 50′ to help locate and maintain the castings in their fixtured, dimensionally stabilized/located positions for treatment.

Whether the fixtures are mounted directly to the conveying mechanism of the heat treatment furnace and/or any subsequent quenching and/or aging chambers, as illustrated in FIG. 1, or are independently or freely moveable with the castings, such as generally illustrated in FIG. 2, the fixtures further can be removed from the system 10/10′ as needed and subjected to a straightening operation as needed to ensure the fixtures are free from distortion or warping, which could correspondingly cause warping or other distortion of the castings themselves as they are subjected to solution heat treatment and/or quenching. Such straightening operations thus can help ensure the castings are maintained within dimensional tolerances following solution heat treatment and quenching.

Still further, as illustrated in FIG. 4, the fixtures also can comprise indexed fixturing structures 50″, including one- or multiple-piece structures having a closable clam shell or similar structure. In the embodiment shown in FIG. 4, each indexed fixturing structure 50″ can include a first or primary casting fixture/section 51A mounted to and movable along the conveying mechanism 48. A secondary or auxiliary casting fixture 51B, which can comprise a clamp or cover plate internally located within the furnace chamber 46, also can engage the castings to provide further stability and protection against distortion to the castings during heat treatment and/or quenching thereof. For example, as indicated in FIG. 4, the secondary casting fixture 51B of each indexed fixturing structure can be selectively lowered into engagement on top of the castings held within corresponding primary fixtures 51A and generally are moved in timed relation therewith as the castings are moved along their heat treatment path through the heat treatment furnace chamber 46. The secondary fixtures 51B can also be substantially stationary with respect to the longitudinal movement of the castings along their path 31 through the furnace chamber, and selectively engaged with the primary fixtures 51A as the primary fixtures are moved in a stepped or indexed fashion along their path of travel through the furnace chamber, such as engaging and supporting the castings at various heat application positions or stations as heat is applied thereto, and releasing the castings for their movement to a next or downstream heating position or station. The secondary fixtures further can comprise removable plates or covers placed over and resting on top of the casting, or can be applied to the casting by their guide/control rods 51C to enable control of pressure applied to the castings by the secondary fixture 51B to prevent distortion and/or elongation of the castings.

As indicated in FIGS. 3A-3C, the fixturing of the castings presents and helps maintain the castings in stabilized indexed positions with the X, Y and Z coordinates of the castings in a known alignment with respect to the path of travel of the castings through the furnace and/or quench chambers. Thus, castings and the core apertures 49 thereof can be located in a desired position or alignment so that as the castings are moved through the quench station, targeted high pressure flows of a quenching fluid material, such as water or air, can be directed at the core apertures in order to facilitate quenching of the castings, while at the same time helping to remove any internal core materials therefrom.

As further indicated in FIG. 1, in one embodiment, the castings can be placed or loaded into their fixtures, or each fixture with a casting positioned therein can be fed into the solution heat treatment station 45 through an initial or entry area 52 thereof. While this entry area 52 is shown in FIGS. 1 and 2 as being generally open, it will be understood by those skilled in the art that the entry area of the heat treatment furnace further can comprise an ante-chamber or other enclosed area in which the castings initially will be placed onto the conveying mechanism 48 of the heat treatment station 45 for feeding into the heat treatment furnace chamber 46. In addition, one or more temperature sensor(s) 53 can be provided at the entry area 52 to monitor the temperature of the castings as they are placed onto the conveying mechanism 48, including being placed within individual fixtures thereof.

The temperature sensor(s) 53 can provide monitored temperature readings of the castings to the system control. Based on this monitored temperature, the system control can determine an initial heat application level or temperature to be applied to the castings to facilitate the rapid heat-up of the castings to a process part stabilization temperature for the metal thereof. Alternatively, the system control can determine whether the castings have fallen too far below their short cycle solution heat treatment temperature and thus either can be rejected/recycled or transferred to a holding area, which could include the retention or holding area 32 adjacent the casting station 11 or a separate, auxiliary holding area, for temporarily storing the castings as heat is applied thereto to heat them to the desired furnace introduction temperature.

The castings also can be subjected to application of heat via one or more applicators 54 in response to the monitored temperature of the castings in order to further moderate and maintain or raise the castings at or above their retention temperature prior to entry of the castings into the heat treatment furnace chamber 46 of the heat treatment station 45. Such applicators 54 can include one or more nozzles applying a heated fluid such as air, thermal oils or other fluid media, or could include infrared or radiant heating elements or other types of heating systems as will be understood by those skilled in the art. Still further, heat can be applied to the castings and to the fixtures for preheating the castings and fixtures prior to their entry into the heat treatment furnace chamber 46 in order to minimize heat loss/transfer between the castings and their fixtures and/or to facilitate the rapid heat up of the castings to their short cycle solution heat treatment temperature and thereafter the conducting of solution heat treatment thereof preferably within a shortened heat treatment cycle time of about 30-40 minutes, and preferably about 30 minutes or less. For example, the castings (and their fixtures) can be subjected to preheating to an extent such that once introduced into the furnace chamber 46, the castings can reach a temperature sufficient to start solution heat treatment thereof in less than about 10-15 minutes and subsequently undergo solution heat treatment within about 5-15 minutes.

In addition, the furnace chamber 46 can have a reduced size or length, for example being about 15-20 feet in length, although different size furnaces also can be provided depending on the size of the castings being processed therethrough. The furnace chamber 46 further can include 4-8 heating positions, which can be defined by location or orientation of one or more heating applicators 60 such as nozzles or blowers that can be arranged at varying spaced locations along the path of travel 31 of the castings through the heat treatment chamber as indicated in FIGS. 1 and 2. As further illustrated in FIG. 1, such heating positions or locations also can be provided within separate stations or sub-chambers 46A and 46B wherein different temperatures or heating environments can be provided.

During heating of the high pressure die castings C for solution heat treatment within the system of the present invention, the castings typically can be reheated from a low temperature, which can be as low as an ambient temperature wherein the castings are substantially cooled and solidified or can be at a desired furnace introduction temperature as discussed above, to a temperature ranging from approximately 50-30° C. below the heat treatment temperature thereof. For example, as illustrated in FIG. 6, depending upon the thickness of the casting and the metal material used to form the casting, the castings can be rapidly heated to a part process stabilization temperature (PPST) within about 10-15 minutes, and possibly less depending on pre-heating and/or prior control of the temperature of the castings above a furnace introduction or retention temperature. The PPST is a temperature below which the temperature of the castings is rapidly increased upon application of heat thereto, but as the temperature of the castings approaches/reaches the PPST, the heating curve for the metal material of the casting substantially flattens and the time required to further raise the temperature of the castings from this PPST up to the solution heat treatment temperature for the metal of the casting can be substantially equal to or longer than the time required to initially heat the casting to its PPST.

However, given the susceptibility of high pressure die cast castings to bubbling and distortion when exposed to substantially high temperatures as required for heat treatment for extended periods of time, rather than subject the castings to further application of heat at substantially increased temperatures generally needed to raise the temperature of the castings from their PPST up to the known solution heat treatment temperature therefor, the castings instead will be moved through a part process stabilization temperature or soak chamber or area wherein the castings will be exposed to a heating environment having a temperature typically within the range of the PPST for the metal of the castings for an extended period of time.

By way of example and not limitation, as indicated in FIG. 1, in a first chamber or station 46A of the furnace chamber 46 of the heat treatment station 45 shown in FIG. 1, the castings C can be exposed to application of heat at substantially elevated temperatures. Heating elements 60, which can include infrared or other radiant heating elements, blowers, nozzles and/or burners or other similar heating elements, will apply a high temperature fluid media (e.g., heated air at temperatures upwards of 490°-600° C., or greater) to the castings to rapidly raise the temperature of the castings from their furnace introduction temperature, or from a substantially cooled or ambient temperature, up to their part process stabilization temperature (PPST) within an initial heat-up period, e.g., within approximately 5-15 minutes. The temperature of the castings also can be monitored such as by sensors 70A within the furnace chamber 46, or by sensors 70B within the fixtures, during such an initial rapid heating period to detect the temperature of the castings approaching their PPST, wherein the heating of the castings slows from the rapid heat-up as shown in FIG. 6.

Based on such monitored temperature or after a predetermined time, i.e., 5-10 minutes, the castings can be indexed to a next heating station or position along the initial heating chamber. This next heating position can be at a location or alignment in which heat or a high temperature fluid media is no longer directly applied to the castings, but the castings are still maintained within an elevated temperature environment, i.e., within a portion of the furnace chamber in which the temperature of the air ranges from approximately 440-520° C. This can include exposing the castings to temperatures approximately at or around the solution heat treatment temperatures for the metal thereof, although it will be understood that other temperatures also can be utilized depending upon the metal material used to form the castings.

Once the castings are determined to have substantially reached or possibly exceeded their PPST, (i.e., by monitoring of the casting temperatures) or after a desired time (e.g., 5-10 minutes), the castings then can be passed to a downstream heating chamber or zone, such as indicated at 46B in FIG. 1. In this downstream heating chamber or zone, the castings can be moved between additional heating positions or stations and will be subjected to lower temperatures, i.e., at or below the solution heat treatment temperature the metal thereof, such as within a range of about 400° C.-420° C. for example, although other temperatures also can be used based on the cast material, as needed to maintain the castings at or around their PPST for an additional time. The castings can be permitted to thereafter soak for approximately 5-15 minutes or longer, to accomplish the solution heat treatment of the castings with the potential danger of the castings being subjected to blistering and/or further distortion from overheating due to exposure to higher temperatures generally needed for raising the pressurized die cast metal castings fully to the solution heat treatment temperature for the metal thereof being substantially reduced.

Accordingly, as the castings are moved through the heat treatment furnace chamber 46 of the short cycle solution heat treatment station 45, they can be subjected to temperatures of about 400°-420° C. up to about 600° C. at varying stages of the process to accomplish solution heat treatment thereof in about 30-40 minutes or less with enhanced efficiency article minimizing potential effects of overheating on the castings. As the castings reach the end of the heat treatment furnace chamber 46, they will be passed through a door or other portal 76 and into a quench chamber, either as a part of the heat treatment station 45 as shown in FIG. 1 at 47, or as a separate station or chamber 80 as shown in FIG. 2.

While FIG. 1 illustrates the furnace chamber 46 as including two separate chambers, including an initial, rapid heat-up chamber 46A and a PPST or soak chamber 46B downstream from the initial chamber, it will be understood by those skilled in the art that the furnace chamber 46 does not necessarily have to be subdivided into discrete, separated sub-chambers. Instead, as indicated in FIG. 2, the furnace chamber 46 can be provided with a series of spaced heat application locations or positions at which a high temperature fluid media, such as air, thermal oils, etc., can be applied at varying temperatures. In addition, the operation of the furnace chamber present system 10/10′ for solution heat treatment of high pressure die castings can enable a reduction in the number of heating applicators or devices along the furnace chamber 46 of the solution heat treatment station 45. By applying substantial heat and/or subjecting the castings to higher temperature applications of heat at the upstream or initial portions of the heat treatment chamber 46, the castings can be rapidly raised to their PPST, but thereafter, minimal further application of heat to the castings, in addition to residual heat provided by the initial high temperature heat applicators, may be needed to maintain the atmosphere or temperature within the furnace chamber at a desired PPST or soak temperature as the castings are conveyed further along the heat treatment chamber in the direction of arrows 31 to complete their solution heat treatment cycle.

Still further, a series of adjacent furnace chambers 46 also can be provided, such as part a combined solution heat treatment station or in close proximity to each other. In one embodiment, each chamber can be arranged in a side-by-side arrangement or series, each including a separate entry and conveying mechanism. The series of furnace chambers can thus alternate receipt of castings from the retention area of one or more pouring stations as needed to accommodate increased casting/production rates. The furnace chambers also can be controlled to divert excess heat therefrom to one of the other chambers to avoid waste of energy/heat during slowed production times. FIGS. 3A-3C illustrate alternative example embodiments of furnace chambers 46 for the short cycle solution heat treatment station 45 for heat treatment of the castings at shortened heat treatment cycle times, for example, within approximately 30 minutes or less.

For example, FIG. 3A illustrates a furnace chamber 46 through which the castings are moved with heated air or other fluid media being supplied or drawn into the chamber, as indicated by arrows 61 through heaters 62 and to a blower or other recirculating device 63, with the reheated air being redirected down the sides of the chamber, as indicated by arrows 64, and applied from the sides of the castings via a plenum, nozzles or other applicators indicated at 65, so as to create a heated environment within the chamber sufficient to heat treat the castings. FIG. 3B illustrates an alternative heat treatment chamber in which the castings, here shown as being held within a fixture 50, are subjected to high pressure fluid media flows, which can include air, thermal oils, or other heated media supplied or blown into the chamber by blowers or nozzles 66 and directed against the castings, as indicated by arrows 67 at increased flow velocities of upwards of about 10-250 feet per second or greater. FIGS. 3A and 3B further illustrate the systems in which, to the extent that internal cores within the castings are broken down and dislodged from the castings, or can be collected and removed via a conveyor mechanism such as belt conveyor 69 shown in FIG. 3B.

In another alternative embodiment, as indicated in FIG. 3C, the heat treatment furnace chamber 46 can include a series of spaced conveyor mechanisms 48A and 48B. Although two vertically spaced conveyors 48A and 48B are illustrated in FIG. 3C, it will be understood that additional conveyors, either aligned in a vertically stacked arrangement or with the conveyors arranged in a side-by-side configuration, also can be used. In the present embodiment, the vertically stacked conveyors 48A and 48B can be moved at generally the same speed or rate, but their fixtures can be arranged at different spacings to enable alternating placement of castings on the 2 conveyors. In addition, the conveyors also could be moved at different rates or intervals to provide for alternating placement of castings thereon. The transfer mechanism 36 (FIGS. 1 and 2) moving the castings from the holding/retention zone 32 adjacent the casting station 11 and into the heat treatment station 45 can alternate the placement of the castings between the conveyors 48A and 48B as needed to potentially help avoid a backlog of castings, delaying their entry into the heat treatment station and/or to enable multiple casting or pouring stations to feed their castings into a shared or common heat treatment station.

As additionally illustrated in FIG. 3C, in some embodiments, the castings can be subjected to high pressure heated air flows, or other fluid media, directed downwardly toward the castings, as indicated by arrows 71, via one or more fans or nozzle/blower assemblies 72. The fans or nozzle/blower assemblies 72 generally can be linked to or in communication with a heat source such as an external burner, etc., such as indicated at 75, for heating the air fluid being applied by the blower assemblies which can apply heated air or other fluid media toward the castings at increased flow velocities of upwards 40-250 feet per second or more, including possibly up to 350 feet per second or greater in some applications. The heated air flows further can be recaptured and directed along the sides of the heat treatment furnace chamber 46, as indicated by arrows 73, back to the fans or nozzles, typically passing through a heating mechanism, such as a blower, infrared heat or other, similar heating mechanism 74 to reheat the recirculated air or other fluid media for application to the castings.

As further indicated in FIGS. 1 and 2, heat from the molten metal reservoir or storage area 27 also can be routed to the heat treatment station 45. Typically, such captured heat, as well as smoke and other byproducts of combustion coming from the reservoir of molten metal can be captured and redirected, as indicated by arrow 57 into the heat treatment furnace chamber 46 of the heat treatment furnace to help conserve heat and reduce heating costs thereof. As an alternative, such recaptured heat from the molten metal reservoir also can be redirected, in whole or in part, to the holding/retention zone 32 immediately downstream from the casting station 11, as indicated by dashed arrow 58, for use helping maintain or moderate the temperature of the castings during removal of the gating materials therefrom and/or prior to the castings being transferred to the entry zone of the heat treatment furnace. In still a further alternative, a portion of the recaptured heat coming from the reservoir of molten metal 27 being transferred to the heat treatment furnace also can be diverted and applied to the castings received within the entry area 52 or the furnace chamber 46 of the heat treatment station 45, as indicated by arrow 59, for use in assisting in the preheating or initial heat up of the castings to their short cycle solution heat treatment temperature in the entry area 52.

Upon completion of the short cycle solution heat treatment step or phase the castings can be fed directly to the quench chamber or station as a next, integrated operative step in the process of the present invention, for substantially rapidly quenching the castings, typically within one-three minutes. Longer quench times also can be used depending on casting sizes and materials. In the quench chamber, the castings will be subjected to application of a cooling media such as air, water, oil and/or mixtures of air, water and/or oil in the quench chamber. As indicated in FIGS. 1, 2 and 5A-5C during such quenching, the castings will be held in their fixtures (including being engaged and held within a fixture 83 mounted to a transfer mechanism 82), which will support and dimensionally stabilize the castings as fans, nozzles or blowers 77 (FIG. 5A) apply the cooling fluid media to the castings as indicated by arrows 78, to quench the castings and return the temperature of the castings to approximately an ambient or normalized temperature.

As shown in FIG. 5B, the castings generally will be subjected to a progressive quenching operation, wherein as the castings enter the quench chamber 47, a cooling mist or air initially can be applied to each casting at a low pressure or velocity through nozzles/blowers 77. The cooling mist or air further typically will be applied from multiple directions to facilitate and foster substantially even cooling across the casting. As the castings are moved along and/or as the time the castings are retained within the quench chamber increases, the volume and/or velocity of the cooling air or fluid being applied to the castings will progressively increase as the castings cool (and thus harden) to provide a controlled cooling of the castings. The quenching flows further can be increased at selected areas of the castings, e.g., at thicker or denser portions thereof, to further enhance/speed cooling and promote consistent cooling of the castings in their fixtures.

The progressive quenching of the castings is further facilitated by the placement/engagement of the castings within their fixtures, which enables the castings to be positioned or located in an indexed position with known X, Y and Z coordinates. Thus, as the casings enter the quench chamber, the castings can be positioned or aligned so that as flows of a quenching fluid material, such as water, oil, air or combinations thereof, can be directed at desired parts/areas of the castings, including at the core apertures in order to facilitate the rapid quenching of the castings, while at the same time helping to remove any internal core materials therefrom. In addition to locating the castings in known, indexed positions, the mounting of the castings within the fixtures, help protect the castings from pressurized or increased coolant flows and holds the castings in alignment and against distortion as they are rapidly cooled/quenched, to thus maintain dimensional stability and geometric casting accuracy as the castings are subjected to quenching treatments.

As a final quench step shown in FIG. 5C, the castings further can be subjected to dunking within a quench tank 100. Such a quench tank 100 can be provided as a separate quench chamber such as chamber 87B of FIG. 2, or can be provided below a single or primary quench chamber 85 in which the progressive quenching operation is conducted, as shown in FIGS. 5B-5C. In addition, as the castings are quenched, they further can be subjected to removal of the internal core materials 26 therein. For example, the internal cores can be formed with a water soluble binder material such that as the castings are sprayed with water or dunked in a bath of cooling fluids such as water, the internal cores also can be broken down and dislodged therefrom. The cores additionally can be removed by application of high pressure air applied to the castings for cooling and for removing or dislodging the internal core materials through the core apertures 49 formed in the castings.

In an alternative embodiment of the present system 10′ illustrated in FIG. 2, the short cycle solution heat treatment station 45 can be separate from a downstream quench station 80, as an alternative to having the quench station 47 included as a chamber of the heat treatment station 45 as shown in FIG. 1. In some embodiments, the short cycle solution heat treatment station 45 may or may not include fixtures carried on or mounted to a conveyor for moving the castings therethrough. A transfer mechanism 82, such as a crane, robotic arm, or other, similar transfer mechanism having a fixture/gripper 83, generally can be provided adjacent the downstream end door 76 of the heat treatment furnace chamber 46. The transfer mechanism 82 will engage and transfer the finished solution heat treated castings to the quench station.

The castings can be removed from their fixtures 50′ conveying them through the short cycle solution heat treatment station, and transferred into a fixture 84 mounted to a conveyor 86 extending through the quench station 80, or the entire fixture 50′ can be transferred, with its casting maintained therein to the conveyor 86 of the quench station 80. Alternatively, as indicated in FIGS. 5B-5C, the transfer mechanism 82 itself can include or comprise the fixture 83 for each casting, i.e., the castings can be engaged by a gripper or carrier mounted to a robotic arm or carried by an overhead conveying mechanism and in which the castings can be received and supported in a pre-determined dimensionally stabilized orientation or alignment and conveyed through/supported within the quench chamber. The casting can be fixtured within the gripper/fixture of the transfer mechanism, or held by their gating or feeder materials, with their castings located in a known, indexed position and supported against distortion and/or deformation as the quenching flows are applied thereto, as shown in FIG. 5B. Thereafter, the transfer mechanism 82 can transfer the castings C to a next station or transfer line 89 to remove the castings for storage and/or further processing.

As shown in FIG. 2, the quench chamber 80 can include a primary or single chamber 85, or multiple chambers 87A and 87B, in which different fluid media can be applied to the castings for quenching the castings. For example, in one of the chambers, i.e., 87A, water or other cooling fluid can be progressively applied to the castings as discussed above and thereafter the castings can be moved into a second chamber where they can be submerged in a quench tank 100 (FIGS. 5B-5C) for completing the quenching of the castings and removal of any cores therefrom, or subjected to application of cooling air such as by fans, blowers, nozzles, etc., 88 (FIG. 2) to help dry and further clean the castings, as well as substantially cool the castings down to an ambient temperature.

As additionally indicated in FIG. 2, the system 10 also can include an aging station 90 positioned downstream from the quench station 80. The aging station 90 generally will include a furnace chamber 91 having a conveyor 92, and one or more heat sources 93 such as blowers, burners, etc. for supplying heat to the chamber 91. The castings will be received within the aging station 90 and can be maintained therein while being subjected to elevated temperatures or heat in order to subject the castings to aging treatments as needed or desired.

The present system is adapted to facilitate the short cycle solution heat treatment pressurized of die cast metal components at an accelerated more efficient rate, preferably within about 30-40 minutes, and preferably without about 30 minutes or less, though longer times could also be used as needed, followed by rapid quenching of the components. The present system and process further provides for the fixturing of the castings so as to maintain the castings in a dimensionally stable, supported alignment during the solution heat treatment and quenching to maintain the castings against distortion, warping, elongation, or other undesirable defects in the alignment and/or configuration of the finished castings. In addition, the heating of the castings during solution heat treatment can be controlled to enable the rapid heat-up of the castings to a part process stabilization temperature (PPST) for the metal thereof, followed by movement of the castings into an area or environment wherein the castings continue to be exposed to heat at temperatures substantially close to their PPST, and generally at or below the solution heat treatment temperature therefor for an additional time to accomplish the solution heat treatment thereof with the potential for bubbling and other undesirable effects due to overheating of the castings being minimized.

The system also enables the use of reclaimed or recaptured heat from the molten metal material used for the die casting process to be applied to the castings at various points along their path of travel from the casting station through the heat treatment station in order to conserve energy and reduce waste heat. Additionally, by monitoring the castings throughout the process of removing the castings from their dies and degating of the castings, and thereafter during transfer from a holding or retention zone to the heat treatment furnace, heat can be applied to the castings as needed to moderate and arrest the cooling of the castings and thereafter maintain the temperature of the castings at or above a desired retention or furnace introduction temperature. Such temperature control can enable the further solidification of the castings to an extent needed for die removal and degating, but which temperature is sufficiently close to the short cycle solution heat treatment temperature required for the castings so as to enable the castings to be rapidly heated to their short cycle solution heat treatment temperature and undergo solution heat treatment within a desired time period of less than about 30-40 minutes, as well as potentially providing a further savings in the amount of heat required for the initial heat-up of the castings. Any castings that are below such a desired/determined or furnace introduction temperature also can be detected and either removed for recycling or transfer back to the retention area or an alternative holding area, or can otherwise be heated prior to moving into the short cycle solution heat treatment station as desired.

The foregoing description generally illustrates and describes various embodiments of the present invention. It will, however, be understood by those skilled in the art that various changes and modifications can be made to the above-discussed construction of the present invention without departing from the spirit and scope of the invention as disclosed herein, and that it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as being illustrative, and not to be taken in a limiting sense. Furthermore the scope of the present disclosure shall be construed to cover various modifications, combinations, additions, alterations, etc., above and to the above-described embodiments, which shall be considered to be within the scope of the present invention. Accordingly, various features and characteristics of the present invention as discussed herein may be selectively interchanged and applied to other illustrated and non-illustrated embodiments of the invention, and numerous variations, modifications, and additions further can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims

1. A method of processing pressurized die cast metal articles, comprising:

inserting a molten metal material into a die at a casting station;

moving the die to a retention area and retaining the metal within the die for a time sufficient for the metal to solidify to form a casting;

moving the casting from the retention area into a furnace chamber of a short cycle solution heat treatment station;

fixturing the casting for movement through the furnace chamber of the short cycle solution heat treatment station with the casting dimensionally stabilized in a defined, indexed position; and

subjecting the casting to solution heat treatment including exposing the casting to heat at a temperature above a solution heat treatment temperature for the metal of the casting for an initial heat-up period, and thereafter maintaining the casting in the furnace chamber at a temperature sufficient to enable solution heat treatment of the casting within a reduced heat treatment cycle time.

2. The method of claim 1, wherein the pouring station includes a molten metal holding area, and further comprising capturing heat from the holding area and redirecting the captured heat into the heat treatment furnace chamber.

3. The method of claim 1, wherein the pouring station includes a molten metal holding area, and further comprising capturing heat from the holding area and redirecting the captured heat to a retention area along the transfer path of the castings prior to entry of the castings into the furnace chamber of the heat treatment station.

4. The method of claim 1, wherein the die includes a core about which the casting is formed, and wherein placing the casting within the heat treatment furnace comprises aligning at least a portion of the casting and/or a core opening of the casting with a series of applicators that apply heated fluid flows toward at least a portion of the casting and/or the core opening to heat treat the casting and remove the core from the casting.

5. The method of claim 1, wherein placing the casting within the heat treatment furnace in an indexed position comprises positioning the casting in a first position with X, Y and Z axes of the casting oriented in a known first orientation, with respect to a first plurality of applicators.

6. The method of claim 5, and further comprising moving the casting to a second position with the casting oriented in a known, second orientation, different from the first orientation so that at least a portion of the die and/or a core opening are in alignment with a second plurality of nozzles; and directing fluid pressure from the second plurality of nozzles at the die and/or core opening for heat treating the casting.

7. The method of claim 5, wherein the fluid flows are applied at the casting at a velocity of at least about 50 ft/sec.

8. The method of claim 1, wherein the heat treatment station further comprises an entry chamber defining a retention area for receiving the casting after removal of the casting from its die and prior to entry into the furnace chamber, and a quench chamber downstream from the furnace chamber for quenching the casting.

9. The method of claim 1, further comprising moving the casting from the furnace chamber and into a quench chamber upon completion of solution heat treatment of the casting, and quenching the casting.

10. The method of claim 9, wherein moving the casting into the quench chamber comprises engaging the casting within a casting fixture configured to hold the casting in a stabilized arrangement to substantially ensure dimensional accuracy of the casting and limit casting distortion during quenching of the casting.

11. The method of claim 9, further comprising removing a core from the casting during quenching.

12. The method of claim 9, wherein quenching the casting comprises applying water, air, mist, fluid, oil or a combination of fluids and/or air.

13. The method of claim 12, wherein quenching the casting further comprises applying a fluid media under high pressure or dunking the casting in a tank.

14. The method of claim 1, wherein inserting the molten metal material into the die comprises injecting the molten metal into the die through a gate passage.

15. The method of claim 14, further comprising removing a gating formed along the casting prior to placing the casting within the heat treatment furnace.

16. The method of claim 14, wherein the molten metal is injected into the die in a high pressure die casting process by a piston wherein the piston is moved at an injection speed of at least about 3 to 10 m/sec and a flow velocity of the molten metal through the gate passage is at least about 25 to 80 m/sec.

17. The method of claim 14, wherein the molten metal is injected into the die in a low pressure casting process at pressures of about 2-20 psi.

18. The method of claim 1, further comprising removing a gating formed with the casting, and moderating and arresting cooling of the casting during removing of the gating.

19. The method of claim 1, wherein moving the casting from the retention area comprises engaging a gating formed along the casting with a transfer mechanism and moving the casting with the casting held by its gating.

20. The method of claim 1, wherein fixturing the casting within the heat treatment furnace further comprises locating the casting in a fixture for movement through the furnace chamber and/or for quenching to limit the casting distortion and promote geometric casting accuracy as the casting moves through the heat treatment station, and/or during quenching.

21. The method of claim 20, further comprising placing the fixture with the casting received therein on a conveyance system, moving the casting through the heat treatment station, and transferring the fixture with the casting therein to a quench chamber for quenching the casting.

22. The method of claim 20, further comprising applying heat to the casting and/or to the fixture in which the casting is received prior to entry of the casting into the heat treatment furnace to maintain or increase the temperature of the casting up to or above the short cycle solution heat treatment temperature prior to heat treatment.

23. The method of claim 20, wherein the fixture comprises a loose-toleranced carrier, configured to engage and hold the casting at selected positions thereof to facilitate geometric accuracy as the casting moves through the heat treatment station, and/or during quenching.

24. The method of claim 20, wherein the fixture comprises a carrier configured to substantially match a configuration of the casting to maintain the casting in a dimensionally stabilized position during solution heat treatment and/or quenching of the casting.

25. The method of claim 1, further comprising engaging the castings with a transfer mechanism, moving the casting from the heat treatment station to a quenching station, and locating the casting within a fixture in the quenching station to limit distortion as the casting is quenched.

26. The method of claim 26, further comprising applying an age treatment to the casting after quenching.

27. The method of claim 1, wherein the shortened heat treatment cycle time is less than about 35 minutes.

28. The method of claim 1, further comprising exposing the casting to quenching after solution heat treating the casting.

29. The method of claim 28, further comprising removing an internal core from the casting during quenching.

30. The method of claim 28, and wherein exposing the casting to quenching comprises placing the casting in an indexed position within a quench chamber for quenching the casting with X, Y and Z axes of the casting oriented in a known first orientation, and wherein a core opening of the casting is located in alignment with at least one of a plurality of applicators.

31. The method of claim 1, further comprising after formation of the casting, while the die and casting are retained in the retention area, removing the casting from the die and monitoring a temperature of the casting and applying heat to the casting as needed to arrest cooling of the casting at a temperature at or above a furnace introduction temperature prior to solution heat treatment of the casting.

32. The method of claim 31, wherein if the casting has not reached the pre-determined furnace introduction temperature, the casting is either rejected or is placed in a casting holding location and heat is applied to the casting until the casting reaches the pre-determined furnace introduction temperature.

33. The method of claim 1, wherein the furnace chamber of the short cycle solution heat treatment station comprises multiple conveyors extending therethrough, each of the conveyors including a series of fixtures for receiving a casting therein, and wherein placing the casting within the heat treatment furnace comprises selectively positioning the casting within an open fixture of one of the conveyors.

34. The method of claim 1, wherein fixturing the casting within the heat treatment furnace chamber comprises locating the casting within a first fixture for moving the casting through the heat treatment furnace chamber, and engaging the casting with a secondary casting fixture inside the heat treatment furnace chamber to limit casting distortion and to promote geometric casting accuracy during heat treatment of the casting.

35. The method of claim 1, wherein subjecting the casting to solution heat treatment comprises:

heating the casting at the temperature above the solution heat treatment temperature to raise a temperature of the metal of the casting to a part process stabilization temperature therefor; and

moving the casting to a soak area wherein the casting is exposed to a heated environment at a temperature less than the solution heat treatment temperature for the metal of the casting.