Single-piece cooling blocks for casting and molding
A block for use in a die casting or molding system receives manufacturing material for distribution into a runner system of a die or mold and cooling fluid for transferring heat away from the block. The block comprises a single-piece body and a plurality of cooling bores. The single-piece body includes features for distributing the manufacturing material, and has a first face, a second face and a plurality of side surfaces disposed between the first face and second face. The plurality of bores are positioned between the side faces and form cooling channels for receiving the cooling fluid.
Die casting and injection molding are a popular methods for forming articles of manufacture from metallic alloys, synthetic materials and other manufacturing materials, especially for thin walled parts. In hot chamber die casting, for example, molten zinc or magnesium is pushed from a crucible, or pot, into a die casting system through a nozzle. The molten metal enters the die casting system through a sprue where it then travels through a runner system before entering the die cavity of a mold. The molten metal flows into the die cavity, where it solidifies and forms an article having a shape matching the die cavity. The solidified articles are then ejected from the mold, so that the process can be repeated. It is advantageous to cycle the molten metal through the runners and die cavity and then cool it down as fast as possible to keep cycle times down, and in turn keep production time and costs down.
One way to keep cycle times down is to control the temperature of the molten metal so that it enters the die at the optimal temperature to allow it to both flow through the runner system rapidly and cool rapidly. Temperature controlled sprue systems are commonly used to control the temperature and volume of molten metal that enters the runner system and the mold. In a temperature controlled sprue system, cooling fluid, such as water, is circulated through the inside of the die and around the sprue in order to remove heat from the die casting system that has been absorbed from the molten metal at the desired time, rate and location.
In these types of systems, cooling blocks, including sprue blocks and spreader blocks, contain systems of channels for circulating cooling fluids through the cooling block very near where the molten metal enters the die at the sprue. This allows for control of the temperature of the molten metal as it enters the die casting system. When cooling fluid is circulated through the cooling blocks, heat from the molten metal is absorbed by the blocks and dissipated by the cooling water. This reduces the time required to solidify the molten metal in the die cavity and the runner system, which in turn keeps cycle times down. In conventional cooling blocks the cooling channels are formed by machining several pieces that when fit together form a cooling block having appropriate cooling channels. The pieces then must be brazed, welded or otherwise joined together to form a seal capable of withstanding high pressures generated during casting or molding. Thus, the joints between the pieces produce a potential for failure during the manufacturing process. Conventional cooling blocks therefore require multiple manufacturing steps, each requiring additional time and money to complete. As such, there is a need for a cooling block having a much simpler construction and mode of manufacture.
BRIEF SUMMARY OF THE INVENTIONThe present invention is directed toward a cooling block for use in a die casting or molding system. The block receives a manufacturing material for distribution into a runner system of a die or mold and cooling fluid for transferring heat away from the block. The block comprises a single-piece body and a plurality of cooling bores. The single-piece body has features for distributing the manufacturing material, and includes a first face, a second face and a plurality of side surfaces disposed between the first face and second face. The plurality of bores are positioned between the side surfaces and form cooling channels for receiving the cooling fluid.
The cooling channels, including channels 44A-44C, channels 46A-46C and bores 45A-45H, are machined or otherwise fabricated into sprue block 38 and spreader block 40 such that sprue block 38 and spreader block 40 each can be fabricated from a single piece of material. Having sprue block 38 and spreader block 40 made from single solid pieces of material simplifies the manufacture and improves the performance of cooling block 18. For example, cooling block 18A is made from a single cast piece, rather than the typical four required to form the sprue and appropriately placed cooling channels, which saves time required for casting and machining four pieces. Solid blocks also increase the heat transfer efficiency of cooling block 18 by eliminating braze lines and other discontinuities. Also, unitary, single-piece blocks eliminate the risk of ruptures or failures of joined pieces, particularly brazed joints, caused by high pressures in casting system 10. Additionally, cooling features for runner 30 can be easily incorporated into cooling block 18B without the need of additional pieces.
Sprue block water channels 44A-44G are machined, or otherwise fabricated, into sprue block 38 in a pattern that allows cooling fluid to circulate around sprue 26. Generally, cooling channels need not be laid out in any particular pattern, but are laid out such that cooling fluid can be distributed around a substantial portion of sprue 26 within a close proximity of sprue 26 to efficiently transfer heat, and can be systematically plugged to facilitate one-way circulation. Cooling channels 44A-44G are close enough to sprue 26 to transfer heat, but do not impart any undue stresses into block 38. In one embodiment, cooling channels 44A-44G are approximately one inch from the center of sprue 26 at their closest point. Cooling channels 44A-44G are formed into sprue block 38 such that they comprise an intersecting loop around sprue 26, and thus transfer heat from around the circumference of sprue 26. In the embodiment shown seven cooling channels are used, but in other embodiments any number of channels can be used to connect a circuit around sprue 26. As such, a plurality of the cooling channels can be plugged such that a closed-circuit for circulating cooling fluid is formed.
Cooling bores 45A-45H are drilled, or otherwise fabricated, into sprue block 38 such that each one intersects at least one of cooling channels 44A-44G. Cooling bores 45A-45H include baffles such that water circulating in cooling channels 44A-44G is deflected transversely to the flow pattern of cooling channels 44A-44G. As such, cooling fluid is directed along the length of sprue 26. Cooling bores 45A-45G are formed into the front face of sprue block 38 on the same face that sprue 26 receives material from crucible 20, the same face on which seat 50 is located. Cooling bores 45A-45H are typically distributed evenly around sprue 26 in a circular pattern. In the embodiment shown, eight cooling bores are spaced approximately forty-five degrees apart around sprue 26, and comprise approximately 7/16 inch bores spaced about one inch from the center of sprue 26. Cooling bores 45A-45H are arranged such that a line formed by the two cooling bores closest to each side of sprue block 38 is parallel to that side. For example, cooling bores 45A and 45H formaline parallel to side 52 of sprue block 38, and cooling bores 45B and 45C form a line parallel to side 54. This type of arrangement allows cooling channels 44A-44G to be formed such that they easily and simply intersect cooling bores 45A-45H.
Cooling channel 44B is formed perpendicularly into side 54 of sprue block 38 such that it intersects bore 45B. Cooling channel 44A is formed perpendicularly into side 52 such that it intersects channel 44A at bore 45B. Cooling channel 44G is formed perpendicularly into side 56 of sprue block 38 such that it intersects both bores 45A and 45H, and continues through to connect with cooling channel 44A. Cooling channel 44G is therefore perpendicular to cooling channel 44A and parallel to cooling channel 44B. Cooling channel 44E is formed perpendicularly into side 58 of sprue block 38 such that it intersects both bores 45F and 45G, and continues through to connect with cooling channel 45G. Cooling channel 44D is also formed perpendicularly into side 58 such that it intersects bore 45C and channel 44C. Cooling channel 44F is formed perpendicularly into side 56 such that it intersects both bores 45E and 45D and connects cooling channels 44E and 44D. Finally, cooling channel 44C is formed perpendicularly into side 54 of sprue block 38 such that is intersects cooling channel 44D at bore 45C. As such cooling channels 44A-44G form a loop around sprue 26 and, in conjunction with a plurality of plugs, form a one way circuit around sprue 26.
Cooling fluid can be directed into sprue block 38 at channel 44B, such as indicated with arrow A, and is able to continue into cooling channel 44A. Plug 60A is placed into the opening of channel 44A at side 52 to prevent cooling fluid from exiting sprue block 38 at side 52, and to direct the cooling fluid into cooling channel 44G. Plug 60B is placed into the opening of channel 44G at side 56 to prevent cooling fluid from exiting sprue block 38 at side 52, and to direct the cooling fluid into cooling channel 44E. Plugs 60C and 60D are placed into channels 44F and 44E, respectively, to prevent cooling fluid from exiting sprue block 38 at side 56 and side 58, and to direct cooling fluid into cooling channel 44F such that it is routed toward cooling channel 44D. Plug 60E prevents cooling fluid from exiting block 38 at side 58 and directs the cooling fluid to channel 44C. Cooling channel 44C remains unplugged whereby the cooling fluid is permitted to exit sprue block 38, as indicated by arrow B. Thus, cooling channels 44A-44G and plugs 60A-60E form a one-way circuit around sprue 26. The cooling fluid can therefore be circulated through sprue block 38 in order to cool sprue 26 around nearly its entire circumference. Sprue 26 can further be cooled along its length through cooling bores 45A-45G.
In other embodiments of sprue block 38, cascade type cooling can be used. In which case, a cascade water junction is placed into cooling bores 45A-45H and cooling fluid is injected directly into cooling bores 45A-45H through the water junction. The cooling fluid enters through an entrance at the water junction and empties through an exit inside the baffle. Cooling fluid enters and exits the interior of sprue block 38 and additional cross channels are optional. Cascade type cooling functions to cool down or otherwise control the temperature of sprue 26 and sprue block 38 in order to assist in regulating the temperature of molten metal flowing through sprue block 38, similar to regular baffle type cooling.
The cooling system of the present invention allows for simpler manufacturing and improved performance of cooling blocks. For example, since each block is comprised of a single piece, complete with cooling channels, no brazing is required to form a part with intricate cooling channels. Thus, the overall strength of each cooling block is increased and the risk of bursting a joint between joined parts is eliminated.
Runner 30 is a small channel that is machined out of spreader block 40 that is positioned along runner portion 67 of spreader block 40 and allows material to flow to die cavity 16. Spreader block water channel 46A and baffle channel 54 are used to circulate cooling water through spreader block 40 in order to control heat transfer between sprue post 28 and the molten metal traveling through runner 30. Spreader block mounting holes 64A-64D are used to couple spreader block 40 to moving die half 14 with threaded fasteners, or in some such similar fashion. Mounting holes 46A-46D are typically placed in the corners of spreader block 40.
Runner portion 67 has a length I that allows runner 30 to extend from sprue post 28 to the runner system of a mold or die, such as runner 34. Runner 30 begins at the tip of sprue post 28 and terminates at outlet 32. Sprue post receives material from nozzle 24 through sprue 26, thus allowing material to flow directly from sprue post 28 into runner 34 of the die halves 12 and 14. No additional components or pieces are necessary to connect sprue block 38 and spreader block 40 with runner 34.
In order to keep spreader block 40 and the material at a desired temperature, sprue post 28 and runner 30 are temperature controlled using cooling channels 46A-46C, baffle channel 66 and baffle 68.
Cooling channel 46A is positioned so that it passes through spreader block 40 adjacent sprue post 28. Cooling channel 46A intersects baffle channel 66, which enters spreader block 40 on a face opposite the face on which sprue post 28 is located, and is positioned directly opposite of sprue post 28. Cooling fluid is passed through cooling channel 46A and baffle 68, similar to baffles 62A and 62B of sprue block 38, and deflects the cooling fluid into baffle channel 66 such that sprue post 28 can be temperature controlled. The cooling of spreader 28 also assists in dissipating heat from the injected material flowing through sprue 26 and thus assists in controlling temperatures and cycle times in system 10. Additionally, cooling channels 46B and 46C extend along runner portion 67 of spreader block 40 to assist in cooling runner 30. Runner portion 67 extends far enough to reach die halves 12 and 14 so that additional runner extensions are eliminated. In order to optimize temperature control in cooling block 18 along runner 30, additional cooling channels are required. However, the number and position of cooling channels included in block 40 varies depending on the size, number and positioning of runners fabricated into spreader block 40. Spreader block 40 may include additional runners extending from sprue post 28 to die halves 12 and 14. As such, additional cooling channels can be positioned along spreader block 40 to cool each additional runner.
In other embodiments of spreader block 40, cascade type cooling can be used similar to that which was described in conjunction with sprue block 38 in
The relative sizes of cooling blocks 18A and 18B shown in
Both sprue block 38 and spreader block 40 can be manufactured from materials with high thermal conductivities, such as tool steels, heat-treated steels, copper, beryllium and/or beryllium-free materials, and combinations thereof In one embodiment, sprue block 38 and spreader block 40 are made of heat treated AISI H-13 steel.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
Claims
1. A cooling block for use in a molding or casting system, wherein the block receives manufacturing material for distribution into a runner system of a mold or die and cooling fluid for transferring heat away from the block, the cooling block comprising:
- a single-piece body having features for distributing the manufacturing material, the body comprising: a first face; a second face; and a plurality of side surfaces disposed between the first face and the second face; and
- a plurality of bores positioned between the side surfaces and forming cooling channels for receiving cooling fluid such that temperature of the features and manufacturing material can be controlled.
2. The cooling block of claim 1 wherein the features include a sprue having a length extending from the first face to the second face and for directing the manufacturing material into the runner system.
3. The cooling block of claim 2 wherein the plurality of bores form a channel encircling the sprue such that cooling fluid can be circulated around a circumference of the sprue.
4. The cooling block of claim 3 wherein the plurality of bores include a plurality of transverse bores extending into the first face around the sprue, wherein the plurality of transverse bores intersect the channel encircling the sprue such that cooling fluid can be circulated along a length of the sprue.
5. The cooling block of claim 1 wherein the features include a sprue post for receiving the manufacturing material into the runner system of the die or mold.
6. The cooling block of claim 5 wherein the plurality of bores includes a bore extending into the second face of the block such that it extends into the sprue post.
7. The cooling block of claim 5 and further comprising a runner portion for linking the spreader post with the runner system of the die or mold.
8. The cooling block of claim 7 wherein the plurality of bores includes a bore extending into one of the plurality of side surfaces for cooling the runner portion.
9. A sprue block for use in a casting or molding system, the sprue block comprising:
- a single-piece body comprising: a first face; a second face; and a plurality of side surfaces disposed between the first face and the second face;
- a sprue running from the first face to the second face for receiving material for distribution into a runner system of a die or mold; and
- a plurality of bores extending into the single-piece body for receiving cooling fluid for transferring heat away from the single-piece sprue block.
10. The sprue block of claim 9 wherein the plurality of bores form intersections that form a pathway through the single-piece body.
11. The sprue block of claim 9 wherein the plurality of bores form a channel between the first and second faces and encircle the sprue such that cooling fluid can be circulated around a circumference of the sprue.
12. The sprue block of claim 11 wherein some of the plurality of bores include plugs such that cooling fluid is directed through the pathways.
13. The sprue block of claim 9 wherein the plurality of bores include a plurality of transverse bores extending into the first face around the sprue such that cooling fluid can be circulated along a length of the sprue.
14. The sprue block of claim 13 wherein the plurality of transverse bores include baffles for directing cooling fluid along a length of each transverse bore.
15. The sprue block of claim 9 wherein the plurality of bores comprises:
- a plurality of lateral bores forming a channel encircling a circumference of the sprue;
- a plurality of transverse bores around the sprue extending into the first face along a length of the sprue; and
- wherein the plurality of transverse bores intersect the plurality of lateral bores such that cooling fluid can be circulated along a length of the sprue and around the circumference of the sprue.
16. The sprue block of claim 15 wherein:
- first and second lateral bores extend into a first side surface and intersect first and second transverse bores, respectively;
- third and fourth lateral bores extending into second and third side surfaces generally perpendicular to the first and second lateral bores and intersecting the first and second transverse bores, respectively;
- fifth and sixth lateral bores extending into a fourth side surface and intersecting the third and fourth lateral bores, respectively, and intersecting third and fourth transverse bores, respectively; and
- a seventh lateral bore extending into the third side surface and intersecting the fifth and sixth bores, and a fifth transverse bore.
17. A spreader block for use in a casting or molding system, the spreader block comprising:
- a single-piece body comprising: a first face comprising: a spreader post for distributing material into a runner system of a die or mold; and a runner portion for linking the spreader post with the runner system die or mold; a second face having a first cooling bore extending into the spreader post for receiving cooling fluid for transferring heat away from the block; and a plurality of side surfaces disposed between the first and second faces.
18. The spreader block of claim 15 and further comprising a second cooling bore extending inward from one of the side surfaces and intersecting the first cooling bore.
19. The spreader block of claim 18 and further comprising a third cooling bore extending inward from one of the side surfaces for cooling the runner portion.
20. The spreader block of claim 19 and further comprising a runner formed into the runner portion of the first surface connecting a tip of the spreader post with the runner system of the die or mold.
Type: Application
Filed: Aug 18, 2006
Publication Date: Feb 21, 2008
Inventor: Richard L. Dubay (Coon Rapids, MN)
Application Number: 11/506,697
International Classification: B22D 17/04 (20060101); B22D 17/08 (20060101);