SAND PRINTED MOLD PACKAGE FOR CASTING A WHEEL ASSEMBLY HAVING DIRECTIONAL SOLIDIFICATION FEATURES
A mold package for casting a wheel assembly includes a sand printed drag mold having a cavity with a chill support chamber and a metal chill received in the support chamber. The mold package further includes at least one sand printed mold insert received in the cavity of the sand printed drag mold and a sand printed cope mold coupled to the sand printed drag mold such that a casting cavity for the wheel assembly is created by the exterior inner surfaces of the cope mold, the drag mold and the at least one insert.
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The present invention generally relates to the use of additive manufacturing techniques for creating mold components or sand mold packages for use in casting prototype wheel assemblies for vehicle testing.
BACKGROUND OF THE INVENTIONMold packages are often fabricated to cast molded parts and these mold packages will generally vary depending on the application and cast product requirements.
In developing prototype wheel assemblies, a mold package must be created to cast the wheel wherein a molten metal material will be poured into the mold package to form cast wheels. Such mold packages have generally been produced using subtractive manufacturing techniques such as using a CNC machine to carve molds from metal billets to form cope and drag mold packages having a mold cavity representing the shape of a wheel. Inherent with subtractive manufacturing techniques, the mold designer is limited as subtractive manufacturing techniques cannot produce all the specific geometrical configurations that may be incorporated in a wheel design such as undercuts and expanding cavities. Further, given the nature of a prototype wheel being used as a prototype for vehicle testing, it is not necessary to create a mold package that has the tolerances or cycle life of a mold package which would be used for a wheel that is in regular production. Thus, there is a desire to create mold packages that can incorporate intricate design features of various types of prototype wheels, wherein the mold package is able to be produced relatively quickly so that the prototype wheel can be cast and tested. Further, it is desirable to have a mold package that can be used for the prototype wheel assembly, but that does not have the manufacturing and design lead time of a standard production mold core package. Further, it is desirable to have a method which includes a mold forming technique that is capable of precisely creating the mold core package such that the resulting cast past is a near net shape of the wheel.
SUMMARY OF THE INVENTIONAccording to one aspect of the present invention, a mold package for casting a wheel includes a sand printed drag mold having a cavity with a chill support chamber and a metal chill received in the support chamber. The mold package further includes at least one sand printed mold insert received in the cavity of the sand printed drag mold and a sand printed cope mold coupled to the sand printed drag mold such that a casting cavity for the wheel assembly is created by the exterior inner surfaces of the cope mold, the drag mold and the at least one insert.
Another aspect of the present invention includes, a method of casting a wheel assembly including sand printing a drag mold, a cope mold and at least one mold insert, wherein the drag mold includes a cavity and a chill support chamber, and further wherein and the cope mold includes a frustum projection having a lower surface defining a wheel disk pattern. The method further includes positioning a metal chill in the chill support chamber of the drag mold and inserting the mold insert into the cavity of the drag mold. A casting cavity is formed or defined by closing the cope mold on the drag mold such that the frustum projection of the cope mold is generally disposed within the cavity of the drag mold. The casting cavity is the near net shape of the desired casting. A sprue or channel is incorporated into the cope mold such that the sprue is in fluid communication with the casting cavity. The method further includes casting a molten alloy into the casting cavity, such that a least a portion of the molten alloy is disposed adjacent to the chill. The molten alloy is then allowed to directionally solidify in the casting cavity to form a wheel, wherein the molten alloy solidifies beginning with molten alloy disposed adjacent to the chill.
Yet another aspect of the present invention includes, a method of casting a prototype wheel assembly wherein the method includes sand printing a sacrificial cope mold portion and a sacrificial drag mold portion of a mold package. The cope and drag mold portions have walls defining at least in part a mold cavity for a prototype wheel. A chill is positioned in the drag mold and at least one internal core is positioned within either the cope mold portion or the drag mold portion. The at least one internal core is configured to define at least in part a hub cavity, a disk cavity and a rim cavity for the cast prototype wheel assembly within the mold cavity. The method further includes closing the cope and drag mold portions around the at least one internal core to form a mold package and casting a molten material into the mold cavity, such that a least a portion of the molten material contacts the chill. The molten alloy is then allowed to directionally solidify in the casting cavity to form a wheel assembly, wherein the molten alloy solidifies beginning with molten alloy in contact with the chill. The method finally includes breaking away the sacrificial cope mold portion and the sacrificial drag mold portion to form a wheel assembly having a hub section, a disk section and a rim section.
These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings.
In the drawings:
For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
The present invention uses an additive manufacturing technique to produce a mold package, and specifically, uses a sandprinting process to create a sand printed mold package. The printing of a sand mold package using a sandprinting device is generally initiated by acquiring a three-dimensional (3D) data design for a wheel assembly using a CAD model program. As further explained below, the 3D data design can be for a wheel assembly, and particularly, for a prototype wheel assembly, such that the data can be used to create a sand printed mold package that can be used to cast a prototype wheel assembly using a molten alloy. The sandprinting device is capable of printing various sand mold packages such that several different designs of prototype wheel assemblies can be created without the associated costs and workup time necessary to create a mold core package from blocks of metal using subtractive manufacturing techniques.
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As used throughout this disclosure, the terms “mold package”, “mold core package” or “sand mold package” will refer to sand printed molds that are ready for casting of a molten material. The term “molds” will refer to a component of a mold package and the term “cores” refers to an insert that is inserted into a mold package for displacing molten material as cast into the mold core package. Thus, the combination of sand printed molds and cores creates a mold core package used with a metal chill for casting a prototype wheel assembly. For purposes of the description of the formation of mold core packages or sand mold packages using the three-dimensional printing process discussed below, a sand mold package 200 as shown in
The printing device 42 includes a hopper 46 at a deposition trough 48, which lays a thin layer of activated fine particulate 50, such as silica sand, ceramic-sand mixes, etc., inside the print area 44. The particulate 50 may be of any size, including 0.002 mm to 2 mm in diameter. The printing device 42 also includes a binder deposition device or binder dispenser 52. As disclosed in detail below, the binder dispenser 52 sprays a thin layer of binder or binding agent 16 in a configuration or pattern 80 of a single layer of a desired sand printed mold component. Repetition of the layering of sand 50 and spraying of binding agent 16 by the binder dispenser 52 results in the production of a three-dimensional sand mold component comprised of a plurality of the stacked particulate layers. The 3D sand mold package is manufactured additively over a length of time sufficient to print each thin layer of the fine particulate 50 in succession, such that each layer of bound particulate is further bound to adjacent layers, to form a completed sand mold component. Each thin layer measures approximately 0.28 mm. A completed sand mold package made up of various sand printed components will ultimately be used as a sacrificial mold to fabricate or cast a metal part, such as the wheel assembly shown in
With specific reference to
It is contemplated that a CAD program, or any other form of 3D modeling software, can be used to provide sufficient information for the 3D printing device 42 to form the desired sand mold structure. Prior to activation of the 3D printing device 42, a predetermined quantity of the sand or fine particulate 50 is dispensed into the hopper 46 by a particulate spout 62 as shown in
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In assembly, the chamber 112 formed on the bottom wall 110 of the drag mold 100 provides a chill support cavity for a base chill, such as the chill plates depicted in
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After filing the disk casting cavity, the molten material 212 then generally travels as indicated by the arrows in
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Given that the mold packages of the present invention are sacrificial sand printed mold packages, there is no need to incorporate intricate designs for cooling lines and other complex thermal control elements in printing the mold package for the casting of a prototype wheel assembly. This is because the base chill 120 allows for directional solidification of the molten material 212 cast in the mold core package 200. The directional solidification of the molten material 212, as shown in
The sandprinting techniques of the present invention are used to create mold components to create a sand printed mold package that is capable of casting prototype wheel assemblies. The present invention allows for experimental prototype wheel assembly designs to be quickly produced without the traditional foundry die design used in the prior art which typically involves large design lead times, high scrap rates, and less than optimal production rates. The present invention eliminates the need for producing production quality mold core packages for casting a wheel assembly and replaces them with sacrificial sand printed mold core packages which can be quickly made and intricately designed based on 3D CAD software. In this way, experimental prototype wheel designs can be quickly produced at much lower costs for use in vehicle testing.
It will be understood by one having ordinary skill in the art that construction of the described invention and other components is not limited to any specific material. Other exemplary embodiments of the invention disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.
For purposes of this disclosure, the term “coupled” (in all of its forms, couple, coupling, coupled, etc.) generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature or may be removable or releasable in nature unless otherwise stated.
It is also important to note that the construction and arrangement of the elements of the invention as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.
It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present invention. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.
It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present invention, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.
Claims
1. A mold package for casting a wheel assembly, comprising:
- a sand printed drag mold having a cavity with a chill support chamber;
- a metal chill received in the support chamber;
- at least one sand printed mold insert received in the cavity of the sand printed drag mold;
- a sand printed cope mold coupled to the sand printed drag mold thereby defining a wheel casting cavity disposed therebetween.
2. The mold package of claim 1, wherein the cavity of the drag mold is defined by a bottom wall having sidewalls extending upwardly therefrom, wherein the chill support chamber is disposed on the bottom wall.
3. The mold package of claim 2, wherein the cope mold further comprises an upper surface and a lower surface with riser cavities disposed therebetween opening into the casting cavity;
- a frustum projection extending downwardly from the lower surface, wherein the frustum projection further includes a patterned lower surface;
- a sprue disposed in the cope mold having an upper inlet port disposed on the upper surface of the cope mold and an outlet port disposed on the patterned lower surface of the frustum projection, wherein the outlet port opens into the casting cavity.
4. The mold package of claim 3, further comprising:
- one or more guide members disposed on upper portions of the sidewalls of the drag mold;
- one or more guide chambers disposed on the lower surface of the cope mold and adapted to align with and engage the one or more guide members of the drag mold in assembly.
5. The mold package of claim 3, wherein the at least one sand printed mold insert comprises sidewalls, a rear wall and an annular front wall.
6. The mold package of claim 5, wherein the rear wall of the at least one sand printed mold insert further comprises upper and lower guide members.
7. The mold package of claim 6, wherein the bottom wall of the drag mold includes guide channels adapted to receive the lower guide members of the at least one insert, and further wherein the cope mold includes guide chambers disposed on the lower surface thereof adapted to receive the upper guide members of the at least one insert.
8. The mold package of claim 5, wherein the sidewalls of the at least one insert are angled sidewalls, and further wherein one or more side walls of the drag mold are angled inwardly towards the cavity of the drag mold and adapted to align with the angled sidewalls of the at least one insert.
9. The mold package of claim 1, wherein the casting cavity comprises a hub casting cavity, a disk casting cavity and a rim casting cavity.
10. A method of casting a wheel assembly, comprising:
- sand printing a drag mold, a cope mold and at least one mold insert, wherein the drag mold includes a cavity and a chill support chamber, and further wherein and the cope mold includes a frustum projection having a lower surface defining a wheel disk pattern;
- positioning a metal chill in the chill support chamber of the drag mold;
- inserting the mold insert into the cavity of the drag mold;
- forming a casting cavity, wherein the cavity is the shape of the desired casting, by closing the cope mold on the drag mold such that the frustum projection of the cope mold is generally disposed within the cavity of the drag mold; and
- casting a molten alloy into the casting cavity, such that a least a portion of the molten alloy is disposed adjacent to the chill; and
- allowing the molten alloy to directionally solidify beginning with molten alloy disposed adjacent to the chill.
11. The method of claim 10, wherein the step of sand printing a drag mold, a cope mold and at least one mold insert further comprises:
- (a) depositing a thin layer of particulate in a printing area of a sand printing device;
- (b) selectively applying a binding agent to the thin layer of particulate to define a cross-section of one of a drag mold, a cope mold and at least one mold insert;
- repeating steps (a) and (b) to produce one of a drag mold, a cope mold and at least one mold insert.
12. The method of claim 10, further comprising:
- providing one or more risers having riser cavities in fluid communication with the casting cavity.
13. The method of claim 12, wherein the step of casting a molten alloy into the mold cavity further comprises:
- filling the riser cavities with the molten alloy.
14. The method of claim 13, wherein the step of allowing the molten alloy to directionally solidify beginning with molten alloy disposed adjacent to the chill further comprises:
- gravitationally feeding molten material to the casting cavity form the riser cavities as the molten alloy solidifies.
15. The method of claim 10, further comprising:
- breaking away the drag mold, the cope mold and the at least one mold insert and removing the metal chill to form a wheel assembly.
16. A method of casting a prototype wheel assembly, comprising:
- sand printing a sacrificial cope mold portion and a sacrificial drag mold portion, the cope and drag mold portions having walls defining at least in part a mold cavity for a prototype wheel;
- positioning a chill in the drag mold;
- positioning at least one internal core within either the cope mold portion or the drag mold portion, the at least one internal core configured to define at least in part a hub cavity, a disk cavity and a rim cavity within the mold cavity;
- closing the cope and drag mold portions around the at least one internal core; and
- casting a molten material into the mold cavity, such that a least a portion of the molten material contacts the chill;
- allowing the molten material to directionally solidify after filling the mold cavity beginning with molten material in contact with the chill;
- breaking away the sacrificial cope mold portion and the sacrificial drag mold portion to form a prototype wheel assembly having a hub section, a disk section and a rim section.
17. The method of claim 16, wherein the step of sand printing a sacrificial cope mold portion and a sacrificial drag mold portion further comprises:
- (a) depositing a thin layer of particulate in a printing area of a sand printing device;
- (b) selectively applying a binding agent to the thin layer of particulate to define a cross-section of one of a sacrificial cope mold portion and a sacrificial drag mold portion;
- repeating steps (a) and (b) to produce one of a sacrificial cope mold portion and a sacrificial drag mold portion.
18. The method of claim 16, further comprising:
- providing one or more risers having riser cavities in fluid communication with the mold cavity; and
- filling the riser cavities with the molten material.
19. The method of claim 18, wherein the step of allowing the molten material to directionally solidify beginning with molten material disposed adjacent to the chill further comprises:
- gravitationally feeding molten material to the casting cavity form the riser cavities as the molten material solidifies.
Type: Application
Filed: Sep 6, 2012
Publication Date: Mar 6, 2014
Applicant: FORD GLOBAL TECHNOLOGIES, INC. (Dearborn, MI)
Inventor: Ronald H. Hasenbusch (Grosse Pointe Park, MI)
Application Number: 13/605,048
International Classification: B22C 9/28 (20060101); B22D 15/00 (20060101); B22D 15/04 (20060101); B22C 9/02 (20060101);