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.
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.
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.
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 defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this invention belong. The terminology used herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
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 die 2 and two undercut dies 3, 4, that can be used together in the production of parts 8 with undercut features. The top die 2, can move substantially vertically, and the undercut dies 3, 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 die 2 is then substantially vertically lowered between the two undercut dies 3, 4, touching each of the two undercut dies 3, 4, and in specific embodiments form fitting against the two undercut dies 3, 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 die 2 can retract substantially vertically allowing space for the undercut dies to retract substantially laterally toward each other freeing them from the undercut feature. The undercut dies 3, 4, are then retracted substantially vertically from the part 8. The side dies 5, 6 retract 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.
In specific embodiments the openings 33 in one or more of the undercut dies 3, 4, are: round, square, triangular, or irregularly shaped, and in specific embodiments the undercut dies 3, 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 system 1 is automated, and the movement of the top die 2 and the undercut dies 3, 4, is performed by robotics from pre-programmed instructions. The robotics can include a separate mechanism for movement of the top die 2 than for any other die. The robotics can include a robotic arm for moving the top die 2.
In specific embodiments one or more parts of the methods are herein repeated for the production of 1, 2, 5, 10, or more parts 8.
In specific embodiments the method is used with injection molding. In specific embodiments plastics are used in molten liquid form to create the parts 8. 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 system 1. 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 system 1 has 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 sides 10 of the top die 2 has one, two, three, four, five, six, seven, eight, nine, or ten ball bearings attached to the top die 2 so as to reduce friction with other dies. In specific embodiments, at least one side 10 of the top die 2 has 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 die 2, the separate part being configured so as to provide for the bearings to move freely within the separate part.
In specific embodiments devices and methods provided herein can be used to produce the part 8, 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 part 8 produced. 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 part 8 comprising an oil pan comprising a bottom flare; ball bearings attached to a side of the top die 2; 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 dies 3, 4; the at least one protrusion comprises one bottom protrusion 22, 24 and one top protrusion 21, 23 on each of the two undercut dies 3, 4; the top die 2 comprises a taper such that a top surface 9 has a largest surface area for any surface of the top die 2 and a bottom surface of the top die 2 has a smallest surface area for the any surface of the top die 2; the molten liquid (such as for a part 8) 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 part 8 comprises an oil pan with a bottom flare; each of the two undercut dies 3, 4 has two top openings 33 for coupling to the moving mechanism 14, 15, and a cylindrical portion of the moving mechanism extends into each of the openings 33 so as to support and move the undercut dies 3, 4; the moving mechanism 14, 15 is hydraulically powered; the top die 2 comprises an end projection 13 and comprises a notch 12 at each of the four corners of the top die 2; the undercut dies 3, 4 are each moved laterally away from each other more than 0.1 inch; the lowering of the top die 2 comprises a hydraulic mechanism that is physically separate from the moving mechanism 14, 15; and/or sliding a guide bar 29, 32, through each of the undercut dies for an opening 34 to provide support.