Undercut die casting and injection molding systems and methods

Method and system for producing a part using die casting or injection molding with a top die and undercut dies that are independently moveable from the top die. In one particular form, the method and system can include a top die and one or more undercut dies that can have a protrusion. The undercut dies can be lowered into a base of the system and moved away from each other, and the top die can be lowered into a receiving portion between the undercut dies. A molten liquid can be introduced into a space between the undercut dies and additional aspects of the system, and after cooling to form a part, the top die can be moved vertically to allow space for the undercut dies to be moved toward each other. The undercut dies can be moved vertically and the part can be removed.

FIELD

This application relates generally to undercut die casting and injection molding systems and methods. More specifically this application relates to a top die that is moveable independent of two undercut dies and which together can be used in systems and methods for producing parts with undercut features.

BACKGROUND

Die casting, where molten metal is inserted into a permanent mold under high pressure, is useful for large scale production of dense, fine-grained structures that have excellent wear and fatigue properties with close manufacturing tolerances because of the permanent nature of the molds. There is a need in the art for undercut die casting processes. Generally, die cast components have a top and bottom die. After a material such as aluminum has been injected into the die and the part has solidified, the top die will be lifted upwards and the part can be removed from the die.

For certain designs, due to the geometry and other constraints, the top die cannot be pulled directly upward. The component would become “locked” to the die. When these conditions exist, the use of expendable molding, such as investment casting or the like is used instead. Sand cores allow for undercut geometric features because they can be broken and shaken to get the locked core out of the component. The sand cast process uses a core made of compressed and bonded sand. These cores are not reusable and require additional machines to make them, making them unsuitable for large-scale part production. Another disadvantage is the extensive clean out process.

There has been a long-felt need in the art for a reusable system for producing undercut features in products in an efficient and effective way that can be used in conjunction with large-scale part production casting techniques such as die casting. The embodiments detailed herein overcome the outlined problems and meet the long-felt need.

SUMMARY

Specific embodiments provided herein describe a method for producing a part with an undercut feature using die casting that includes providing a system that is made up of a top die and one or more undercut dies. In specific embodiments there is a plurality of undercut dies. Undercut dies can have a protrusion or protrusions for producing the undercut feature or features. In specific embodiments the plurality of undercut dies can be lowered into a receiving portion of a base of the system. In specific embodiments the undercut dies can be moved away from each other, and in specific embodiments the top die can be lowered into the receiving portion and between the undercut dies. In specific embodiments a molten liquid or at least one molten liquid can be introduced into a space between the plurality of undercut dies and additional aspects of the system. The molten liquid can be cooled so as to form a part in a solid form where a portion of the part is directly above a portion of the protrusion. The top die can be retracted vertically allowing space for the undercut dies to retract. The undercut dies can be moved toward each other, and can be moved substantially vertically. The part can then be removed.

Additional specific embodiments describe a die casting system for producing a part with undercut features. In specific embodiments the system includes a top die, and one or more undercut dies, and each undercut die can have one or more protrusions. Specific embodiments provide for a moving mechanism configured to move the undercut dies laterally and vertically. In specific embodiments the top die can be moved vertically downward between the undercut dies, and the top die can match a shape of a space between two or more undercut dies so as to produce a form fit for die casting.

Specific embodiments herein provide for a method for producing an oil pan with undercut features using die casting. In specific embodiments the system includes one or more top dies, and can include one or more undercut dies. The undercut dies can have a bottom protrusion or protrusions, and the system can have side dies, and can have a bottom die and a top die or dies. The top dies can be configured to be moved in a vertical direction. The undercut dies can be configured to move laterally and vertically. The lower die can be placed in a receiving portion of a base of a moving mechanism of the system. In specific embodiments the side dies can be placed in the receiving portion of the base of the moving mechanism of the system and on top of the bottom die. The undercut dies can be moved into the receiving portion and between the side dies by vertically lowering the undercut dies into the receiving portion of the base. The undercut dies can be moved substantially laterally away from each other such that each of the undercut die bottom protrusions move under a portion of one of the side dies and there is a space between each of the undercut dies and each of the side dies for receiving a molten liquid such as aluminum. The top die or dies (such as two or more) can be lowered substantially vertically between each undercut die so as to contact each of the undercut dies. A molten liquid such as aluminum can be injected into the system. In specific embodiments the aluminum can be cooled to produce a part such as an oil pan. The top die can be retracted vertically allowing a space for the undercut dies to retract. The undercut dies can be moved toward each other, freeing them from the undercut feature. In specific embodiments the undercut dies can be retracted vertically from the part such as the oil pan. The side dies can be retracted and the part, such as the oil pan, can be removed.

DETAILED DESCRIPTION

Specific embodiments of the present disclosure will now be described. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will provide illustrative embodiments.

Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about,” which is intended to mean up to ±10% of an indicated value. Additionally, the disclosure of any ranges in the specification and claims are to be understood as including the range itself and also anything subsumed therein, as well as endpoints. Unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that numerical ranges and parameters setting forth the broad scope of embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements.

As used herein, the term “substantially vertically” refers generally to movement of a part as described herein in an up or down direction in accord with a standard Cartesian coordinate system along the y-axis; in specific embodiments this refers to straight up or straight down along the y-axis, and in other embodiments refers to movement in the up and/or down direction at an angle of from about zero degrees to about 45 degrees from the y-axis line.

As used herein, the term “substantially laterally” refers generally to movement of a part as described herein in a side to side direction in accord with a standard Cartesian coordinate system along the x-axis; in specific embodiments this refers to straight side to side movement, and in other embodiments refers to movement in the side to side direction at an angle of from about zero degrees to about 45 degrees from the x-axis line.

Embodiments provided herein detail a die cast process utilizing the top die2and two undercut dies3,4, that can be used together in the production of parts8with undercut features. The top die2, can move substantially vertically, and the undercut dies3,4, can each be moved vertically and laterally. In specific embodiments one, two, or more than two dies (3, 4, 5, 6, 7, 8, 9, 10, or more) are made from tool steel and have a smooth surface finish and can be re-used for more than one, several, or many parts. In specific embodiments the undercut dies are placed in position for pouring of a material by substantially lateral and/or substantially vertical movement. The top die2is then substantially vertically lowered between the two undercut dies3,4, touching each of the two undercut dies3,4, and in specific embodiments form fitting against the two undercut dies3,4.

In specific embodiments of this process a material is introduced (such as poured or injected) into the assembled tooling. In specific embodiments the material is aluminum or aluminum alloy. In specific embodiments the material includes aluminum and/or elements of copper, magnesium, manganese, silicon, tin and zinc. Once the introduced material is cooled, the top die2can retract substantially vertically allowing space for the undercut dies to retract substantially laterally toward each other freeing them from the undercut feature. The undercut dies3,4, are then retracted substantially vertically from the part8. The side dies5,6retract substantially laterally and the part can then be removed.

Specific embodiments described herein have superior strength, excellent surface finish and material skin, low porosity, designed geometric features, and lower cost than other methods.

FIG. 1illustrates the undercut die casting system1as described herein. Illustrated is the undercut die casting system1, the top die2, the undercut dies3,4, the side dies5,6, the lower die7, and a part8upon solidification of an introduced, cooled liquid. The molten liquid can be introduced into a space between the undercut dies3,4, and the side dies5,6, as well as between the undercut dies3,4, and the bottom die7, and the shape of the part8is formed from the shape of the space upon cooling of the liquid. In specific embodiments the part8is an oil pan. Also shown inFIG. 1is a Cartesian coordinate system showing the y-axis for vertical direction26and the x-axis for lateral direction27. Illustrated inFIG. 1are the dies in position for introduction of a molten liquid to form the part8upon cooling of the liquid. In specific embodiments the part8is a an oil pan and in specific embodiments the part8is an oil pan with a flared bottom edge formed from bottom protrusions22,24of each of the undercut dies. Oil pans produced by methods provided herein can also have a curved bottom. One or more of the undercut dies3,4, can have a curved bottom or can have a bottom that angles upward linearly as the undercut die3,4extends to an outer periphery (away from the top die when the top die2is placed between the undercut dies3,4). In specific embodiments the undercut die3,4is angled such that the widest part is at the bottom and the narrowest part is at the top. In specific embodiments, devices and/or methods described herein can provide for the oil pan with the flared bottom edge improving/being an improvement over other oil pans by increasing the volume of oil at the lowest point of the pan. This configuration and methods herein provide for increasing the volume of oil near a pick-up tube, preventing oil starvation during extreme vehicle maneuvers. In specific embodiments the flared bottom edge extends out from all of the other portions of the oil pan by about 0.1 inch to about 0.5 inch, or from about 0.1 inch to about 1 inch, or from about 0.1 inch to about 5 inches.

FIG. 2illustrates a perspective view of the top die2of the undercut die casting system1as described herein. Illustrated are the top9, side10, end11, notch12, and end projection13of the top die2. The top die2has a top surface9that is generally rectangularly shaped, and the end projection13can extend out from the rectangle. In specific embodiments there are 1, 2, 3, or 4 notches12in the top surface9of the top die2. Each notch12can act as a receiving point for the top of an undercut die3,4, which can be placed into position at the notch12. The top of each undercut die3,4, can have, in specific embodiments, an opening33(shown inFIG. 4) such that a cylinder25(shown inFIG. 3) of the moving mechanism can be placed partly or fully through the opening33so the moving mechanism14,15(shown inFIG. 3), and the undercut die3,4can be coupled, allowing movement of the undercut die3,4, when the moving mechanism14,15, moves. One or more of the cylinders25can extend/be extended partly or fully through the undercut die3,4, such as from about 25 to about 50 percent through, or from about 50 to about 100 percent through the undercut die3,4. In specific embodiments the opening33does not extend all the way through the undercut dies3,4, and can extend, for example, about 25 percent to about 50 percent through, or about 25 to about 75 percent through, or from about 25 to about 100 percent through. In specific embodiments the cylinder25(and/or any cylinder described herein) has a cylindrical shape, and in other embodiments the cylinder can be of other shapes known in the art, such as round, square, rectangular, or triangular as viewed from the end. In specific embodiment the single undercut die3,4, has the two openings33configured such that one is at each end and at the top of the undercut die, such that the undercut die3,4, has portions that fit in the two notches12of the top die2, and the undercut die3,4, is coupled to the moving mechanism14,15, at two points via two cylinders25,28. In specific embodiments both of the undercut dies3,4, have the two openings33, and there are connections to the moving mechanism14,15via four total cylinders25,28(additional two cylinders are shown inFIG. 4) for the two dies3,4.

FIG. 3illustrates the moving mechanism14,15, the undercut dies3,4, the side dies5,6, the lower die7, the top die2, and base16with receiving portion17of the undercut die casting system1as described herein. The moving mechanism14,15can have the cylinders25,28, configured for coupling of each of the undercut dies3,4at the top of the undercut dies3,4via the openings33. The undercut dies3,4can have top protrusions21,23, and bottom protrusions22,24. In specific embodiments there are a plurality of undercut dies3,4such as 2, 3, 4, 5, 6, 7, 8, 9, 10, or from about 1 to about 5, or from about 1 to about 10, or from about 2 to about 5, or from about 2 to about 10. Specific embodiments provide for one undercut die to be used with a top die as described herein, the one undercut die3,4and the top die2configured to be used with one or two sides dies5,6to provide the part8; in specific embodiments two undercut dies are used though only one has a protrusion, such that a part is produced with an undercut feature on one side. Also shown inFIG. 3is an arrow indicating vertical movement26(in this case downward) of the top die2for top die2placement prior to introducing a material which can be via pouring. The cylindrical parts25,28can move laterally forward and/or back (corresponding to left and/or right on the page ofFIG. 3), moving the undercut dies3,4, about half the length L of the base16; in specific embodiments the lateral movement of the undercut dies3,4, by the cylindrical parts25,28, can be from about 0 to about 10 percent of the base length L, or about 0 to about 20 percent, or about 0 to about 50 percent, or from about 0 to about 75 percent of the base length, or from about 50 to about 75 percent of the base length L. Also shown inFIG. 3are cylinders30,31which can move the undercut dies vertically up and/or down.

In specific embodiments the openings33in one or more of the undercut dies3,4, are: round, square, triangular, or irregularly shaped, and in specific embodiments the undercut dies3,4, are from about 0.1 inch to 0.5 inches in diameter, or from about 0.1 to about 1 inch in diameter.

In specific embodiments one or more of the undercut dies has: one, two, three, four, five, six, seven, eight, nine, or ten protrusions; specific embodiments have from about one to about five or from about one to about ten protrusions. One or more of the protrusions can be greater than 0.1 inches in length and/or diameter, such as about 0.1 to about 0.5 inch, and/or 0.1 to about 1 inch, and/or from about 0.1 to about 5 inches.

In specific embodiments the undercut die casting system1is automated, and the movement of the top die2and the undercut dies3,4, is performed by robotics from pre-programmed instructions. The robotics can include a separate mechanism for movement of the top die2than for any other die. The robotics can include a robotic arm for moving the top die2.

In specific embodiments one or more parts of the methods are herein repeated for the production of 1, 2, 5, 10, or more parts8.

In specific embodiments the method is used with injection molding. In specific embodiments plastics are used in molten liquid form to create the parts8. In specific embodiments the part is produced with injection molding with a host of materials, including metals, glasses, elastomers, confections, thermoplastic, thermosetting polymers, or any combination of these materials.

In specific embodiments liquid material such as molten liquid material is poured into the undercut die casting system1. In specific embodiments molten liquid material is forced into position and cooled to form a shape.

In specific embodiments one or more components of the undercut die system1has one or more ball bearings attached, such as at points where two dies or other components touch, to reduce friction. In specific embodiments the one or both sides10of the top die2has one, two, three, four, five, six, seven, eight, nine, or ten ball bearings attached to the top die2so as to reduce friction with other dies. In specific embodiments, at least one side10of the top die2has from about 1 to about 5 ball bearings, or from about 1 to about 20 ball bearings. In specific embodiments one or more of the bearings is of a spherical shape. In specific embodiments the bearing or bearings are within a separate part affixed to the top die2, the separate part being configured so as to provide for the bearings to move freely within the separate part.

FIG. 4illustrates a perspective view of the moving mechanism14,15of the undercut die casting system1ofFIG. 3depicting guide bar(s)29,32. The guide bars29,32can provide structural support, supporting the weight of the undercut dies3,4. In specific embodiments guide bars29,32are at the top of the die casting system1, in specific embodiments extending the length or substantially the entire length of the base16of the die casting system1; in specific embodiments the die casting system1has two undercut dies3,4and two guide bars29,32, each of the guide bars29,32extending through two of the undercut dies3,4at opposing sides of the base16; in specific embodiments a guide bar29extends entirely through an opening34at the top of one or more of the undercut dies3,4. The opening34is labeled inFIG. 4at the back-side for ease of view, though the opening34(and the opening33also labeled inFIG. 4) are also depicted at the front side of the undercut die cast system1. The guide bars29,32can be stationary, and in specific embodiments the undercut dies3,4can be moved along the guide bar or bars29,32in opposing directions (toward and/or away from each other) by the cylinders25,28. The guide bar or bars29,32can be above or below the cylinders25,28. In specific embodiments the guide bars29,32remain coupled to the undercut dies3,4throughout part or all of the methods provided herein; the top die2can be set in place between the guide bars29,32, such that the part8can be made, and the guide bars29,32, support the weight of the undercut dies3,4, through lateral and vertical movements or the entire process of producing the part8. Methods provided herein can include coupling the undercut dies3,4, to one, two, or more than two guide bars29,32. In specific embodiments the die casting system1has four guide bars (only two are shown inFIG. 4), slideable from each corner of the top of the base and extending toward a center line of the die casting system1to engage the undercut dies3,4. In specific embodiments the guide bars29,32can be slid in place and locked in place. Also shown inFIG. 4are: the lower die7, the side dies5,6, receiving portion of the base17, and undercut die tops18,19.

FIG. 5illustrates the moving mechanism14,15of the undercut die casting system1ofFIG. 4depicting a guide bar29and the top die2placed between the two undercut dies3,4. Also depicted are: the side dies5,6, the bottom die7, the base16, the receiving portion of the base17, the top protrusions21,23, bottom protrusions22,24, and the cylinders25,28,30, and31.

In specific embodiments devices and methods provided herein can be used to produce the part8, wherein the part is an automotive application such as but not limited to: intake manifolds, plenums (air boxes), coolant overflow container, wiper fluid containers, battery trays, and/or HVAC components.

In specific embodiments devices and methods provided herein can be used to accommodate back up material for bolt bosses or fluid passageways or other shape that may cause an undercut condition.

In specific embodiments devices and methods provided herein can be used for non-automotive uses which require or feature an undercut situation.

In specific embodiments devices and methods provided herein can be used to aid packaging concerns by utilizing open voids.

In specific embodiments the oven temperature used in producing the part is 675 degrees Celsius. In specific embodiments the part is produced at from about 675 degrees Celsius to about 700 degrees Celsius, or from about 675 degrees Celsius to about 750 degrees Celsius, or from about 675 degrees Celsius to about 775 degrees Celsius.

In specific embodiments an oil pan is the part8produced. In specific embodiments the dimensions of the oil pan are 520 millimeters long, 258 millimeters wide, and 170 millimeters tall, with the bottom flare being 30 millimeters. In specific embodiments the oil pan length is from about 450 to about 550 millimeters long, the length is from about 225 to 325 millimeters wide, the height is about 125 to about 225 millimeters tall, and the flare out at the bottom is from about 1 millimeter to about 50 millimeters.

Specific systems and methods are described herein have or use: producing the part8comprising an oil pan comprising a bottom flare; ball bearings attached to a side of the top die2; the at least one protrusion comprises one protrusion extending laterally from at least one of the two undercut dies, such that the protrusion extends laterally beyond the perimeter of any other portion of the at least one of the two undercut dies3,4; the at least one protrusion comprises one bottom protrusion22,24and one top protrusion21,23on each of the two undercut dies3,4; the top die2comprises a taper such that a top surface9has a largest surface area for any surface of the top die2and a bottom surface of the top die2has a smallest surface area for the any surface of the top die2; the molten liquid (such as for a part8) comprises at least one of a metal and a plastic; the metal comprises aluminum; the metal comprises from about 40 percent to about 100 percent aluminum; the plurality of undercut dies consists of two undercut dies of a first undercut die and a second undercut die, at least one of which defines said at least one protrusion; the part8comprises an oil pan with a bottom flare; each of the two undercut dies3,4has two top openings33for coupling to the moving mechanism14,15, and a cylindrical portion of the moving mechanism extends into each of the openings33so as to support and move the undercut dies3,4; the moving mechanism14,15is hydraulically powered; the top die2comprises an end projection13and comprises a notch12at each of the four corners of the top die2; the undercut dies3,4are each moved laterally away from each other more than 0.1 inch; the lowering of the top die2comprises a hydraulic mechanism that is physically separate from the moving mechanism14,15; and/or sliding a guide bar29,32, through each of the undercut dies for an opening34to provide support.