Method for reducing ice crystals in high-pressure die-casting part

Abstract

A die-cast part, such as an electric drive unit, is disclosed. A high pressure die casting system and a method of forming a die cast part are also disclosed. The high pressure die casting system includes a shot cartridge having a pouring hole, a launder connected to the pouring hole, a furnace connected to the launder, a mold cavity connected to the shot cartridge by a gate post, and at least one proximal channel below the pouring hole below the shot cartridge. Feedstock is melted in a smelting furnace, flows through a pouring hole through a launder and is transferred into a preheated injection storage barrel. A feedstock is injected into a mold cavity, wherein the temperature of the feedstock is higher than the solidus temperature of the feedstock as it enters the mold cavity.

Description

Background Art

[0001] High pressure die casting is a process for making near-net-like or net-like parts from metals with little post-processing. The process is commonly used for aluminum, zinc, and magnesium. During the process, a plunger forces molten metal from a shot hopper into a closed mold at a relatively high speed. The molten metal cools and begins to solidify in the mold, and once it has solidified enough, the solid is removed from the mold in one go.

[0002] However, if the molten metal partially solidifies in the shot accumulator, the solidified layer near the shot accumulator surface may produce ice crystals or particles that solidify before entering the mold cavity. Ice crystals can produce irregular structures and discontinuities in the finished part. These structures and discontinuities can appear on the surface and inside the part, causing surface defects and internal defects.

[0003] While current high pressure die casting processes and systems achieve their intended purpose, there is still room for advancement in the area of ​​high pressure die casting processes and systems to reduce ice crystals. Summary of the invention

[0004] According to various aspects, the present disclosure is directed to a high pressure die casting system comprising a shot accumulator having a pouring hole, a launder connected to the pouring hole, a furnace connected to the launder, a mold cavity connected to the shot accumulator through a gate post, and a heating system including at least one proximal channel located below the pouring hole below the shot accumulator.

[0005] In the above embodiment, the at least one proximal channel extends to the midpoint of the shot cartridge. In a further embodiment, the at least one proximal channel includes two to six parallel channels parallel to the shot cartridge, and at least one circumferential channel connecting the parallel channels. In a further embodiment, the plurality of parallel channels are spaced around the lower half of the shot cartridge.

[0006] In any of the above embodiments, the at least one distal channel is surrounded by the gate pin around at least a portion of the circumference of the shot accumulator. In a further embodiment, the at least one distal channel includes two distal channels.

[0007] In any of the above embodiments, at least one gate channel is located below the gate column.

[0008] In any of the above embodiments, the heating system comprises a circulator for hot oil connected to at least one of the at least one proximal channel, the at least one distal channel, and the at least one gate channel. Alternatively or additionally, in any of the above embodiments, the heating system comprises at least one heating element selected from a resistive heating element and an inductive heating element inserted into at least one of the at least one proximal channel, the at least one distal channel, and the gate channel.

[0009] In any of the above embodiments, an insulation layer is disposed above the launder, wherein the amount of insulation material and the type of insulation material are selected such that melt temperature loss of the feedstock is less than 20 degrees C. In a further embodiment, the insulation layer is fiberglass.

[0010] According to various additional aspects, the present disclosure is directed to a method of forming a die cast part. The method includes melting a feedstock in a furnace at furnace temperature, preheating a shot accumulator using a heating system including at least one proximal channel, transferring the feedstock through a pouring hole into the shot accumulator via a launder, wherein the at least one proximal channel is located below the pouring hole below the shot accumulator, and advancing a plunger in the shot accumulator according to an injection velocity profile to inject the feedstock into a mold cavity, wherein the temperature of the feedstock is above the solidus temperature of the feedstock as it enters the mold cavity.

[0011] In the above embodiments, the method further comprises circulating a heat transfer fluid through the at least one proximal channel.

[0012] In any of the above embodiments, the furnace temperature is 100 degrees Celsius to 150 degrees Celsius higher than the solidus temperature.

[0013] In any of the above embodiments, the solidus temperature is determined by phase simulation.

[0014] In any of the above embodiments, the method includes simulating the temperature loss of the molten feedstock as it is transferred through the flow channel to determine whether the temperature loss is greater than an allowable temperature loss, and if the temperature is greater than the allowable temperature loss, adjusting the amount of insulation material or the type of insulation material around the flow channel. In a further embodiment, the allowable temperature loss is 20 degrees Celsius or less.

[0015] In any of the above embodiments, the shot hopper is preheated at a preheat temperature, and the preheat temperature and the injection velocity profile are selected by simulating the temperature of the feed in the shot hopper. In a further embodiment, the preheat temperature of the shot hopper is in a range of 150 degrees Celsius to 200 degrees Celsius, and the velocity of the injection velocity profile includes a plurality of velocities in a range of 0.4 meters per second to 0.7 meters per second.

[0016] According to several additional aspects, the present disclosure is directed to an electric drive unit for a vehicle. The electric drive unit includes a housing having a surface. The housing is made of a magnesium alloy and has less than ten ice crystals per square meter of the housing surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described in the present disclosure are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

[0018] Figure 1 Showing ice crystal formation in a die cast part.

[0019] Figure 2 A die casting system according to an embodiment of the present disclosure is shown.

[0020] Figure 3 A shot cartridge and mold are shown according to an embodiment of the present disclosure.

[0021] Figure 4A Shown is the melt temperature profile of a melt advancing in a shot accumulator without including a heating channel in the shot accumulator, with the scale at the bottom of the figure relating to the length of the shot accumulator and the scale on the left representing the temperature in degrees Celsius.

[0022] Figure 4B Shown is the melt temperature profile of a melt advancing in a shot accumulator without including a heating channel in the shot accumulator. The scale at the bottom of the graph relates to the length of the shot accumulator and the scale on the left represents the temperature in degrees Celsius.

[0023] Figure 5A Shown is the melt temperature profile of advancing melt in a shot accumulator with a heating channel included in the shot accumulator according to an embodiment of the present disclosure. The scale at the bottom of the figure is related to the length of the shot accumulator, and the scale on the left represents the temperature in degrees Celsius.

[0024] Figure 5B Shown is the melt temperature profile of advancing melt in a shot accumulator with a heating channel included in the shot accumulator according to an embodiment of the present disclosure. The scale at the bottom of the figure is related to the length of the shot accumulator, and the scale on the left represents the temperature in degrees Celsius.

[0025] Figure 6 The connection between the launder and the fill tube of a metrology well is shown according to an embodiment of the present disclosure.

[0026] Figure 7 Shows the simulated temperature distribution of the melt as it drips into a non-adiabatic shot accumulator. The scale at the bottom of the figure is related to the size of the melt, and the scale on the left represents the temperature in degrees Celsius.

[0027] Figure 8 The simulated temperature distribution of the melt when the melt drips into the adiabatic shot accumulator according to an embodiment of the present disclosure is shown. The scale at the bottom of the figure is related to the size of the melt, and the scale on the left represents the temperature in degrees Celsius.

[0028] Fig. 9 The flowchart of FIG. 1 shows a process of selecting the melt temperature of a feedstock during a die casting process according to an embodiment of the present disclosure.

[0029] Fig.10 An example flow chart of a method for forming a die cast part according to an embodiment of the present disclosure is shown.

[0030] Fig.11 A vehicle including an electric drive unit housing formed using the systems and methods described in this disclosure is shown. DETAILED DESCRIPTION

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application or use. In addition, there is no intention to be bound by any express or implied theory presented in the previous background technology, the invention summary or the following detailed description. It should be understood that throughout the drawings, corresponding reference numerals indicate similar or corresponding parts and features.

[0032] In the claims and the specification, certain elements are designated as "first," "second," "third," "fourth," "fifth," "sixth," and "seventh." These designations are arbitrary and consistent only in the parts in which they appear (i.e., the specification or claims or the summary), and not necessarily between the specification, the claims, and the summary. In this sense, they are not intended to limit the elements in any way, and an element labeled as "second" in a claim may or may not refer to a "second" element also so labeled in the specification. Instead, the elements may be distinguished by their configuration, description, connection, and function.

[0033] As used in the present disclosure, the term "vehicle" is not limited to automobiles. Although the present disclosure mainly describes the present technology in conjunction with die-cast parts used in conjunction with vehicles, the technology is not limited to internal combustion engine vehicles or electric vehicles. These concepts can be used in a variety of applications, such as related to components used in motorcycles, mopeds, locomotives, aircraft, ships and other vehicles, as well as other applications combined with hydrogen fuel cells and applications combined with motors. For example, applications include industrial machines and motors, agricultural equipment, compressors, defense equipment, HVAC (heating, ventilation and air conditioning) systems, residential and commercial generators, and pumps and other parts that require lubrication.

[0034] Reference will now be made in detail to several examples of the present disclosure illustrated in the accompanying drawings. Whenever possible, the same or similar reference numerals may be used in the drawings and description to refer to the same or similar parts or steps. The drawings are in simplified form and not drawn to exact scale.

[0035] The present disclosure relates to high pressure die casting systems and methods for forming die cast parts for vehicles. High pressure die casting is a process for making near-net-like or net-like parts from metal with little or no post-processing. Such parts may include, but are not limited to, electric vehicle drive unit housings, gearbox covers, sensor (including LiDAR) housings, sunshade bars, mounting brackets for motors and stepper motors, shields for telematics and other electronic devices, sensor and airbag housings, fuel intake parts, air conditioning systems, seat belt retractor reels, complex lock cylinders, transmission and chassis components, connectors, brake components, and engine blocks.

[0036] High pressure die casting can be understood as a process in which molten metal is pressed into a sealed mold cavity using a plunger. During the solidification process, the metal is under pressure to compensate for the shrinkage that occurs during the solidification process. In an embodiment, the injection pressure (the pressure at which the molten metal is pressed into the mold cavity) is minimum when the shot hopper is filled in the range of 40% to 50%. The fortification pressure, that is, the pressure that keeps the feed in the mold cavity during solidification, is in the range of 30 megapascals (MPa) to 100 MPa, including all values ​​and ranges therein. High pressure die casting is different from, for example, a gravity system that relies on gravity to fill the mold cavity.

[0037] Figure 1 A portion of a die cast part 100 is shown, including ice crystals 102 present on the surface of the die cast part 100. In the illustrated image, the ice crystals 102 cause fractures in the surface 104 of the die cast part 100. Cracks 106 and other surface deformations 108 can be seen in the surface 104 of the die cast part 100 adjacent to the ice crystals 102. In addition to fractures in the surface 104 and affecting the surface finish, the ice crystals 102 may also reduce local material strength. The ice crystals 102 may be caused by solidification of the skin of the melt while the melt is dwelling in the shot hopper of the die casting machine, i.e., during the period from when the melt is introduced into the shot hopper to when the melt is injected into the mold cavity.

[0038] Figure 2 An image of a high pressure die casting system 200 used in the present disclosure is shown. The high pressure die casting system 200 generally includes a furnace 202 for melting a feedstock 204 in a die casting process. The feedstock 204 includes a metal or metal alloy, which includes one or more of the following metals: magnesium, aluminum, zinc, copper, lead, and tin. The feedstock 204 then flows through a pouring hole 209 through a trough 206 to be delivered to a die casting machine 208, as further described in the present disclosure. The die casting machine 208 injects the feedstock 204 into a die cavity 210 within a mold 212 installed in the die casting machine 208. The die cavity 210 is a negative mold of the shape of the part, and the die cast part formed by the feedstock 204 is in the form of the die cavity 210.

[0039] Figure 3An embodiment of a die casting machine 208 is shown in FIG. The die casting machine 208 typically includes a shot accumulator 302 in which a "shot" of feedstock 204 accumulates before the feedstock 204 is injected (or "shotted") into the die cavity 210 by advancing the plunger 303 toward the die cavity 210. The shot accumulator 302 may be formed from a tool steel such as H13. The shot accumulator 302 is connected to a gate post 304 (also referred to as a "blank"), forming a gate. The gate post 304 is connected to the die cavity 210 by a runner system 306, which may connect the die cavity 210 to the gate post 304 at one or more locations. The mold 212 may include one or more slides 308, each of which is actuated by a cam 310.

[0040] Reference again Figure 2 as well as Figure 3 , a heating system is provided to prevent temperature loss in the die casting system 200. In an embodiment, the heating system includes a circulator 220 that heats a heat transfer fluid 224 (e.g., oil) and circulates it through one or more proximal channels 314 around the shot cartridge 302, one or more distal channels 316 around the shot cartridge near the blank 304, one or more channels 318 below the gate blank 304, and any additional channels in the mold, such as channel 332. The circulator 220 and the channels 314, 316 can be connected using, for example, an insulated hose 226. The mold 212 also includes one or more channels 332 in the mold cavity. The heat transfer fluid 224 is heated in the circulator 220 to a temperature of up to 350 degrees Celsius, including all values ​​and ranges within a range such as 150 degrees Celsius to 200 degrees Celsius, which also circulates the heat transfer fluid 224 through the channels 314, 316, 318. In an alternative or additional embodiment, the heating system includes a heating controller (not shown) including a power supply and circuitry for processing a temperature control algorithm coupled to a plurality of resistive or inductive heating elements located in channels 314 , 316 , 318 .

[0041] In the illustrated embodiment, the proximal passage 314 extends from below the pouring hole 209 at the first end 320 of the shot barrel 302 to a midpoint 322 or near a midpoint 332 of the shot barrel 302. It will be appreciated that in alternative or additional embodiments, the proximal passage 314 may extend to the blank 304. In an embodiment, the proximal passage 314 includes parallel passages 324 that are substantially parallel to the shot barrel 302 and passages 326 that wrap around the shot barrel 302 near or at the midpoint 322 and connect the parallel passages 324. Additionally, the parallel passages 324 may be spaced around the lower half of the shot barrel 302 below the pouring hole 209. For example, in an embodiment, two to six parallel passages 324 may be spaced around the lower half of the shot barrel 302.

[0042] The distal channels 316 are shown as surrounding the entire circumference of the shot accumulator 302 near the billet 304 at the second end 330 of the shot accumulator 302. Two distal channels 316 are shown, however there may be more than two channels, such as up to ten channels, or alternatively, there may be only a single channel. Additionally, the distal channels 316 may only surround a portion of the circumference of the shot accumulator 302. Additionally, a gate channel 318 is disposed below the gate post 304. The channels 314, 316, 318 all form a loop, each loop including an inlet and an outlet connected to the circulator 220 for flowing the heat transfer fluid 224 through the channels 314, 316, 318 and preventing stagnation of the heat transfer fluid 224.

[0043] The proximal channel 314, the distal channel 316, and the gate channel 318 contacted by the molten feedstock 204 are placed within a distance ranging from 50 millimeters (mm) to 2500 mm from the inner wall 312 of the shot cartridge 302, including all values ​​and ranges therein. In addition, the channels 314, 316, 318 can present any number of cross-sections, such as circular, oval, rectangular, or square. In addition, the channels 314, 316, 318 can be machined into a cylinder in which the shot cartridge 302 is formed or otherwise contact the shot cartridge 302.

[0044] Figure 4A and Figure 4B The melt temperature loss of the feedstock 204 excluding the heating system and heating channels 314, 316, 318 is shown, which is determined using a casting process simulation software (such as MagmaSoft, ProCAST, Flow3D, Anycasting simulation software). Upon introduction into the shot accumulator 302, the melt temperature was determined to be 720 degrees Celsius. After 1.6 seconds of residence in the shot accumulator 302, 13% of the mold cavity 210 was filled, and 0.27% of the total weight of the feedstock 204 was found to be solidified. In addition, the temperature of the feedstock 204 decreased by 100 degrees Celsius as it approached the inner wall 312 of the shot accumulator. When the feedstock 204 was advanced 200 mm through the shot accumulator 302 after a residence time of 2.4 seconds, the temperature loss increased to 130 degrees Celsius, 1% of the molten feedstock 204 solidified, and 27% of the mold cavity 210 was filled.

[0045] Figure 5A and Figure 5BA system including heating channels 314, 316, 318 is shown with melt temperature loss of feedstock 204 in shot accumulator 302, which temperature loss is determined using casting process simulation software (e.g., MagmaSoft, ProCAST, Flow3D, Anycasting simulation software). The melt temperature introduced into the shot accumulator was determined to be 720 degrees Celsius. After 1.6 seconds of residence in the shot accumulator 302, 13% of the mold cavity 210 was filled, and zero (0%) total weight of the feedstock 204 was found to be solidified. In addition, the feedstock temperature decreased by 50 degrees Celsius as it approached the inner wall 312 of the shot accumulator. When the molten feedstock 204 was advanced 200 mm through the shot accumulator 302 after 2.4 seconds, the temperature loss increased to 90 degrees Celsius, 0.03% of the feedstock 204 solidified, and 28% of the mold cavity 210 was filled.

[0046] Figure 6 The connection between the shot accumulator 302 and the trough 206 is shown. In the illustrated embodiment, the trough 206 is connected to the shot accumulator 302 via a launder 610; however, it should be understood that the fill hopper shown above the launder 610 can be eliminated. In an embodiment, to reduce temperature losses in the feedstock 204 as the feedstock 204 is added, the launder 610 is covered with an insulating material 614. The insulating material 614 includes, for example, fiberglass, mineral wool, MANNIGLAS (available from Lydall, Rochester, New Hampshire, USA), KAOWOOL blanket (available from THERMAL CERAMICS INC., Augusta, Georgia, USA). In an additional embodiment, the insulating material 614 is applied back to the furnace 202 along the length of the trough 206. The R-value of the insulating material 614 ranges from 2 to 8 per inch, including all values ​​and ranges therein. In addition, the insulating material is applied at a thickness ranging from 0.5 inches to 6 inches, including all values ​​and ranges therein.

[0047] The provision of thermal insulation reduces the loss of melt temperature as the feedstock 204 passes through the flow channel 610 . Figure 7 A simulation of the temperature of the feedstock 204 0.4 seconds after the feedstock 204 is introduced from the slot 206 into the shot hopper 302 without using an insulating material is shown. At this point, the shot hopper 302 is 14% full and 0.03% by weight of the feedstock 204 has solidified. In addition, the melt temperature at the inner wall 612 of the flow channel 610 has dropped by 50 degrees Celsius.

[0048] Figure 8A simulation of the temperature of the feedstock 204 0.4 seconds after the feedstock 204 is introduced from the slot 206 into the shot hopper 302 is shown with the use of an insulating material. At this point, the shot hopper 302 is 14% full and 0.03% by weight of the feedstock 204 has solidified. In addition, the melt temperature at the inner wall 312 of the flow channel 610 has only dropped by 20 degrees Celsius.

[0049] Continue to refer Figure 2 , Figure 3 and Figure 6 ,like Fig. 9 As shown, method 900 shows a simulated die casting process for selecting process parameters and forming a die casting part according to various embodiments. At frame 902, an assumption is made about the temperature of the feedstock 204 when it leaves the furnace 202. In an embodiment, the phase simulation performed at frame 904 is used at frame 906 to select the temperature at which the furnace is used to melt the feedstock 204, that is, the furnace temperature. The phase simulation at frame 904 determines the solidus temperature of the feedstock 204, especially when the feedstock can be a multi-component alloy. The simulation software for performing such simulations may include, for example, CALPHAD programming language, such as ThermoCalc, Pandat, JMatPro, etc. The solidus temperature can be understood as the highest temperature at which the alloy is in a solid state. In addition, the amount of feedstock 204 required to fill the empty cavity in the injection is determined based on the volume of the cavity. It should be noted that the shot cartridge 302 can only be filled by 40% to 50%. Then at box 906, a furnace temperature is specified based on the calculation of the amount of expected temperature loss when the feedstock 204 is transferred from the furnace 202 to the launder 610 and then injected from the shot hopper 302. However, the selected furnace temperature must not exceed a temperature that could degrade the material or components of the material, or cause problems in processing, such as undesirable phase changes in the feedstock 204.

[0050] At block 908, thermal analysis and simulation of the die casting process is performed using the temperature of the feedstock 204 as it leaves the furnace 202 as a constraint. At block 910, the process of the molten feedstock 204 flowing through the insulated runner 610 as described above and entering the pouring hole 209 of the shot accumulator 302 is simulated. At block 912, it is determined whether the melt temperature loss of the feedstock 204 passing through the runner 610 in the simulation is greater than or less than the allowable melt temperature loss T allowable This is determined based on whether the melt temperature drops below the solidus temperature in the flow channel 610 or the shot hopper 302, and the range can be up to, for example, 20 degrees Celsius, including all values ​​and ranges therein, to prevent any temperature loss during injection, causing the melt temperature to drop below the solidus temperature. Casting process simulation can be run using simulation software such as MagmaSoft, ProCAST, Flow3D, Anycasting, etc.

[0051] If the temperature loss at block 912 is greater than the allowable melt temperature loss T allowable , the simulation at box 910 is rerun by modifying parameters (such as the amount or type of insulation material 614 of the launder 610) or by starting with a higher feed melt temperature or furnace temperature. If the temperature loss at box 912 is less than (not greater than) the allowed melt temperature loss T allowable , then at box 914, the simulation software described above is used to perform a simulation to optimize the local shot spool preheat temperature and the jet injection profile at the inner wall 312, including the speed at which the feedstock 204 is advanced through the shot spool 302 under the action of the plunger 303. At box 916, it is determined whether the temperature of the feedstock 204 is lower than the solidus temperature in the shot spool 302, or whether the temperature of the feedstock 204 in the shot spool 302 is too high, so that the feedstock 204 will not be properly solidified in the mold cavity, because solidification may take too long or may present an undesirable phase when solidified due to the cooling profile.

[0052] If the feed material 204 temperature drops below the solidus temperature in the shot sump 302, the injection profile is adjusted and the simulation run of box 914 is repeated. Various aspects of the process can be adjusted to modify the feed material temperature 204 in the shot sump 302 and during injection. For example, the preheat temperature of the shot sump 302 can be adjusted using a heating system. In addition, the velocity profile of the plunger 303 in the shot sump 302, i.e., the injection profile, can be adjusted. As shown below, the injection profile affects the temperature of the feed material 204 in the shot sump 302. However, the injection profile speed is limited; if the profile speed is too fast, turbulence is introduced into the feed material 204, which may cause defects in the die cast part, such as entrained oxides or pores. If the temperature of the feed material 204 does not drop below the solidus temperature in the shot sump 302, the various parameters determined in the above method 900 can be used at box 918 to produce the die cast part.

[0053] During the above-described simulations, various known constraints are input into the system, including, for example, the geometries of the various components of the die casting system 200, the coefficients of thermal expansion of the various materials used in the die casting system 200 and the feedstock 204, and the thermal conductivity k of the various materials used in the die casting system 200 and the feedstock 204. Additionally, various variables are input into the system, including, for example, the temperature of the feedstock 204 exiting the furnace and entering the launder 610, the temperature of the feedstock 204 exiting the launder 610 and entering the shot accumulator 302, the weight of the feedstock transferred through the system 200, and the rate at which the feedstock 204 flows through each portion of the system 200.

[0054] Table 1 provides non-binding examples of the effects of injection profile and oil temperature on feed melt temperature loss. Base speed may represent the speed used in a standard or initial injection profile, and Suggested Speed ​​1 and Suggested Speed ​​2 are exemplary modifications made to the initial profile.

[0055] Table 1 Relationship between injection profile and oil temperature and melt temperature loss

[0056]

[0057]

[0058] As described above, increasing the flow rate throughout the injection profile (i.e., at different plunger positions) can reduce the melt temperature loss of the feedstock 204. This is due to, for example, reducing the residence time of the feedstock 204 in the shot spool 302. The residence time can be understood as the time that the feedstock 204 remains in the shot spool 302.

[0059] Continue to refer Figure 2 , Figure 3 , Figure 6 and Fig. 9 , Fig.10A method 1000 for forming a die cast part is shown. At box 1010, the feedstock 204 is melted in the furnace 202 at the furnace temperature selected at box 906 as described above. In an embodiment, the furnace temperature is in the range of 100 degrees Celsius to 150 degrees Celsius above the solidus temperature, including all values ​​and ranges therein. At box 1012, the feedstock 204 is transferred to the shot accumulator 302 through the slot 206 and the runner 610. Before the feedstock 204 is transferred through the slot 206 and the runner 610, the amount or type of the insulating material 614 surrounding the slot 206 and the runner 610 can be adjusted based on the simulation performed at box 910. In an embodiment, the amount of the insulating material is selected so that the melt temperature loss of the feedstock is less than 20 degrees Celsius, and the type of the insulating material is selected from the above-mentioned insulating materials. The shot accumulator 302 is preheated to the temperature selected at box 914. In an embodiment, the shot accumulator 302 is preheated using a heat transfer fluid heated to a preheat temperature in the range of 150 degrees Celsius to 200 degrees Celsius. In an embodiment, the temperature loss in the shot accumulator 302 is no greater than 50 degrees Celsius. A vacuum is applied to the shot accumulator 302 to prevent the reaction gas including water vapor from entering the shot accumulator 302. At box 1014, the feedstock 204 is injected into the mold cavity 210. In an embodiment, the speed of the injection profile is in the range of 0.4 meters per second to 0.7 meters per second. In addition, in an embodiment, the temperature loss of the feedstock during injection is no greater than 100 degrees Celsius. During injection, the injection profile is selected based on the simulation run at box 914. At box 1016, the feedstock 204 is maintained in the mold cavity 210 under pressure. When the feedstock 204 cools in the mold cavity 210, it shrinks, and pressure is provided by the advancement of the plunger 303 to continue filling the mold cavity 210 with the feedstock 204. Once sufficiently cured, the die cast part is removed from the mold cavity 210 , for example, by manual removal or removal using an ejector system in the mold 212 and triggered by opening the mold 212 to expose the mold cavity 210 .

[0060] In an embodiment, the die-cast part is a drive unit housing for a vehicle motor. Fig.11 , a vehicle 1100 is shown including an electric drive unit 1110 including a housing 1112 formed of, for example, magnesium alloy AE44 (Mg-4% Al-4% Re) using the above-described method and system. The electric drive unit housing has less than ten ice crystals per square meter of housing surface. Alternatively or additionally, more than one die-cast part can be formed during a single cycle. The die-cast parts are drive unit housings, drive unit supports, gearbox covers, sensor (including lidar) housings, sun visor bars, mounting brackets for motors and stepper motors, protective covers for telematics and other electronic devices, sensor and airbag housings, fuel intake parts, air conditioning systems, seat belt retractor reels, complex lock cylinders, transmission and chassis components, connectors, brake components and engine blocks.

[0061] The systems and methods of reducing ice crystals in high pressure die casting disclosed herein provide many advantages. These advantages include, for example, improved mechanical properties of metal castings. These advantages also include, for example, improved surface characteristics. These advantages also include, for example, reduced structural irregularities caused by ice crystals in cast parts. These advantages also include, for example, reduced scrap rates.

[0062] The description of the present disclosure is merely exemplary in nature, and variations that do not depart from the gist of the present disclosure are intended to fall within the scope of the present disclosure. These variations should not be regarded as departing from the spirit and scope of the present disclosure.

Claims

1. A high pressure die casting system, comprising: A shot accumulator including a pouring hole; a runner connected to the pouring hole; a furnace connected to said launder; a mold cavity connected to the shot cartridge via a gate post; as well as A heating system includes at least one proximal channel located below the pouring hole below the shot cartridge.

2. The high pressure die casting system according to claim 1, wherein: The at least one proximal passage extends to a midpoint of the shot cartridge.

3. The high pressure die casting system according to claim 2, wherein: The at least one proximal channel includes two to six parallel channels parallel to the shot cartridge, and at least one circumferential channel connecting the parallel channels.

4. The high pressure die casting system according to claim 3, wherein: The parallel channels are spaced around a lower half of the shot cartridge.

5. The high pressure die casting system of claim 3, further comprising at least one distal passageway extending through the gate pin around at least a portion of the circumference of the shot cassette.

6. The high pressure die casting system according to claim 5, wherein: The at least one distal channel includes two distal channels.

7. The high pressure die casting system of claim 5, further comprising at least one gate channel located below the gate column.

8. The high pressure die casting system according to claim 1, wherein: An insulation layer is provided above the launder, wherein the amount of insulation material and the type of insulation material are selected so that the melt temperature loss provided to the feed is less than 20 degrees Celsius.

9. A method of forming a die-cast part, comprising: melting a feed material in a furnace at a furnace temperature; preheating the shot cartridge using a heating system including at least one proximal channel; transferring the feedstock through a pouring hole into a shot accumulator via a launder, wherein at least one proximal channel is located below the pouring hole below the shot accumulator; and Advancing a plunger in the shot cartridge according to an injection velocity profile to inject the feedstock into a mold cavity, The temperature of the feedstock is higher than the solidus temperature of the feedstock when it enters the mold cavity.

10. An electric drive unit for a vehicle, comprising: A shell having a surface, wherein the shell is formed from a magnesium alloy, wherein the shell has less than ten ice crystals per square meter of the shell surface.

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