Abstract: In a method of controlling the temperature of an injection or diecasting mold, the respective temperature of the mold being detected by at least one sensor and compared to a set point and coolant, in particular cooling water, being metered and added through cooling channels disposed in the mold in dependence on detected overshooting or undershooting of the set point, it is provided, with a view to avoiding any overswinging of the control, that opening the valves for metering the coolant is allocated to one threshold and closing the valves to the other.

Abstract: A plastic article is formed in an injection mold by injecting molten plastic into the injection mold at an elevated temperature, cooling the plastic from the molten condition to a solid condition, and crystallizing a portion of the plastic by slowing down the cooling of said portion.

Abstract: An apparatus for molding composite articles includes a pair of opposed matched-tool mold sections, each having a rigid housing and a thin, semi-rigid membrane removably and sealably mounted on the housing so as to define a fluid-tight chamber therein. The chamber of each mold section is filled with a noncompressible heat-conductive fluid to provide fluid backing to the portions of each membrane defining the molding surfaces of each mold section. A system of temperature control coils extending within each chamber are connected to an external heater/chiller unit to permit circulation therethrough of a suitable temperature control fluid, whereby positive control of the temperature of the backing fluid and, correlatively, the molding surfaces of the membranes.

Abstract: A multi-cavity coinjection mold having a relatively large plurality of cavities for simultaneously molding a relatively large plurality of multi-layered articles including a) a plurality of cavity groups each defining a relatively small plurality of said cavities, a single balanced hot runner for supplying said relatively small plurality of cavities with contiguous different plastics materials, and a valve for sequentially supplying desired contiguous quantities of the plastics materials from plastics material sources, common to all of said groups, to the balanced hot runner; and b) a hot runner manifold system connected to the plastic material sources to supply the plastic materials to all of the valves; and related methods.

Abstract: Disclosed is a method of injection-molding for epoxy resin moldings wherein an epoxy resin composition is used as starting material, a molding cycle is shortened, a continuous molding operation is possible and a waste portion after curing can be minimized as well as an injection-moldable epoxy resin composition excellent in thermal stability possessing latent-type curing characteristics capable of rapidly promoting curing reaction in a metal mold without being cured in an injection molding machine. The aforesaid method is carried out by charging an epoxy resin composition possessing the latent-type curing characteristics into a mini-sprue metal mold which is composed of a manifold part, a mini-sprue part and an ejector-plate part and wherein a metal mold temperature at the manifold part is so maintained that the epoxy resin composition is molten but curing of the composition is not promoted, and injection-molding the composition.

Abstract: There is provided a process for producing a multi-layer molded product having a plurality of thermoplastic resin layers. This process provides for (i) a step of supplying first and second molten thermoplastic resins each through first and second resin supplying gates which are temperature-controllable independently of each other, to between female and male molds kept in an open state with a time difference being provided between supply starts of the first and second resins, and (ii) a step of closing the female and male molds after completion of supply of the first and second resins. The process enables production of high-quality multi-layer molded products having a plurality of resin layers with good repeatability under relatively low resin supply pressure and by single mold closing. Further, high-quality multi-layer molded products can readily be produced without restrictions on materials used.

Abstract: Disclosed is a method for controlling the temperature of a mold for injection molding. The temperature of a front surface portion of an upper mold neighbored a gate which is connected to a spool to which the melted resin is injected through a runner, is controlled as 65-75° C. The temperature of a side surface portion of the upper mold between the front surface portion and a parting line, is controlled as 45-55° C. Then, a cavity portion corresponding to the upper mold is formed. The temperature of a core portion which is positioned at a concave portion of a mould product, is controlled as 35-45° C. The generation of a weld line or a chromic aberration can be restrained.

Abstract: Tool having a molding surface is formed from a flowable material (e.g., powder material) wherein the shape of molding surface is formed from a molding process using a master pattern having a surface with a shape substantially the same as the shape of the molding surface to be formed. The tool has at least one thermal control element located within it and spaced from the molding surface where a component used in forming the thermal control element is located within the flowable material prior to solidifying the material. The powder material is preferably a mixture of metals. The thermal control elements include fluid flow paths, heating elements, temperature sensors, and the like.

Abstract: An injection molding machine, and stack assembly, employing a novel mold gate insert that can decrease the cycle time of the machine, and crystallinity and other defects in the mold gate area of plastic articles. A mold gate insert is described that is formed in two pieces. A first portion of the insert can forms a gate land for valve gated machines, and can thermally shield the nozzle tip. This first portion is made of a wear resistant material having a relatively low thermal conductivity, such as H13 tool steel. A second portion of the insert forms a section of the mold cavity and is made of a relatively highly thermally conductive material, such as beryllium copper. During the cooling phase of the injection cycle, the second portion provides rapid dissipation of heat to cool the section of the mold cavity, while the first portion creates a thermal barrier to shield the nozzle tip from the cooling of the second portion.

Abstract: A preform and container each having a crystallized neck finish and method of making the same, wherein the method involves introducing a first thermoplastic material into a first mold section to form a substantially crystallized neck portion of a preform, and introducing a second thermoplastic material into a second mold section to form a substantially amorphous body-forming portion of a preform. The first material may have a substantially higher crystallization rate than the second material, and/or the first mold section may be at a higher temperature than the second mold section. In one embodiment, an indexer carrying two core sets is movable between first and second cavity sets for sequentially molding the neck portions on the first core set in the first cavity set, and then transferring the cores and neck portions to the second cavity set for molding the body-forming portions.

Abstract: Plastic composite gears and bearings with excellent friction and wear properties and further, plastic composite molded parts with excellent dimensional accuracy, can be presented at a low cost without adding large quantities of solid lubricant and glass fibers, etc., by adding a crystalline nucleus to crystalline polymers, such as polyacetal, polyamide, polyphenylene sulfide, etc.

Abstract: If the surface of metallic mold should not be highly transcribed to the surface of product in injection molding the plastic products, the transcription defects such as weld, shrinkage, etc. are caused to the surface of product. Further, if the resin should be exposed to the surface of high temperature metallic mold more than necessary during the molding, the filler and the like of glass and so forth are contained into the resin, and in this case, they are left over on the surface of metallic mold, resulting in the transcription defect. These problems can be solved by heating the surface temperature of metallic mold higher than the glass transfer temperature of resin if the resin is non-crystal and higher than the fusion point temperature if the resin crystal, with the temperature raising speed of more than 2° C. every second, maintaining this temperature during the resin charging, and by cooling at the lowering speed of more than 2° C. every second after the completion of charging.

Abstract: An apparatus and method for molding thermosetting polymers onto clothing. The apparatus includes at least one molding device, at least one polymer supply and a control system for controlling the operation of the molding devices and polymer supplies. The molding devices include die sets having an input member and a mold. The polymer supplies supply polymers for injection into the input members of the molding devices for use in molding three dimensional bodies of polymers onto substrates such as clothing.

Abstract: Various steps in the operation of an insulated runner injection molding system are automated by computer generated responses to various sensing steps or other steps to thereby reduce the performance requirements of the system operator. In automatic response to a manual operation incident to closure of a machine gate subsequent to removal of a sprue from channel-encasing mold parts, a computer causes the molding system to be adjusted to enable injection of molten plastic into an insulated runner channel to form the insulated runner and through the insulated runner into mold-cavities. In automatic response to sensing such readjustment of the molding system, the computer causes a predetermined quantity of molten plastic to be metered for injection to form the insulated runner. In automatic response to sensing such metering the computer causes the metered quantity to be injected into the channel.

Abstract: The invention provides an injection-molded product of polyglycolic acid obtainable by molding a thermoplastic resin material at an injection temperature ranging from the melting point, Tm of the polymer to 255° C., wherein the thermoplastic resin material comprises polyglycolic acid having a repeating unit represented by the following formula (1): and the following physical properties: (a) the melt viscosity, &eegr;* [as measured at a temperature of (the melting point, Tm of the polymer+20° C.) and a shear rate of 1,000/sec] being 30-10,000 Pa·s; (b) the melting point, Tm being at least 150° C.; (c) the melt enthalpy, &Dgr;Hm being at least 20 J/g; and (d) the density being at least 1.50 g/cm3 as measured in an unoriented, crystallized form, and a production process thereof.

Abstract: A method for forming a molded grommet using a device which includes a fixed mold and a movable mold, the latter having three positions. The first is a closed position, wherein the two molds are adjacent each other with a middle plate between them. Second, there is an intermediate position in which the middle plate and movable mold are spaced apart from the fixed mold. Third, there is an open position, wherein the movable mold is spaced further from the fixed mold than the middle plate. A core is fixed to the movable mold and, when in the closed position; the two molds, the core, and the edge of the middle plate define the molding space into which moldable resin is introduced, thereby forming the grommet with the edge within the channel. As the core moves from the intermediate position to the open position, the middle plate is retained in the intermediate position; therefore, the core is pulled out of the grommet through the axial hollow therein.

Abstract: A molded resin article is prepared by introducing a thermoplastic resin having a temperature greater than a transfer starting temperature into the cavity of a mold, which is retained at a temperature less than the transfer starting temperature, and injection-molding the thermoplastic resin in the mold in which the heat capacity of a surface on the cavity side is set such that the temperature of the thermoplastic resin near the surface of the mold, which resin is cooled in said mold to a temperature less than the transfer starting temperature, is increased again to a temperature exceeding the transfer starting temperature after the cavity is filled with the thermoplastic resin.