CA2159391A1 - Gravity precision sand casting of aluminum and equivalent metals - Google Patents
Gravity precision sand casting of aluminum and equivalent metalsInfo
- Publication number
- CA2159391A1 CA2159391A1 CA002159391A CA2159391A CA2159391A1 CA 2159391 A1 CA2159391 A1 CA 2159391A1 CA 002159391 A CA002159391 A CA 002159391A CA 2159391 A CA2159391 A CA 2159391A CA 2159391 A1 CA2159391 A1 CA 2159391A1
- Authority
- CA
- Canada
- Prior art keywords
- mold
- flow
- sprue
- aluminum
- casting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D37/00—Controlling or regulating the pouring of molten metal from a casting melt-holding vessel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
Abstract
A technique and accompanying apparatus to promote increased yield, improved surface finish and microstructure, and faster cycling time for precision-sand casting process. Aluminum products are cast by: (a) forming a precision sand mold, devoid of risers and/or vents, and a gating system consisting of a gravity feeding sprue and one or more runners effective to carry molten metal from the sprue only to the bottom of the mold cavity;
(b) planting a flow modifier in the gating system between the sprue and mold effective to convert the flow into laminar quiescent flow; and (c) filling the gating system with molten aluminum metal at a rate faster than 4 pounds/second as permitted by the laminar flow that more rapidly fills the mold and acts as a heat sink to prevent a drop in temperature of the in-coming molten metal and thereby increase yield as well as minimizing cycle time.
(b) planting a flow modifier in the gating system between the sprue and mold effective to convert the flow into laminar quiescent flow; and (c) filling the gating system with molten aluminum metal at a rate faster than 4 pounds/second as permitted by the laminar flow that more rapidly fills the mold and acts as a heat sink to prevent a drop in temperature of the in-coming molten metal and thereby increase yield as well as minimizing cycle time.
Description
2159~1 .
GRAVITY PRECISION SAND CASTING OF
ALUMINUM AND ~QulvALENT METALS
Background of the Invention Technical Field This invention relates to using core sand for precision molding of metal castings, particularly aluminum, and more particularly to enhancement of metal yield, metal properties and quality features such as surface finish using such casting technique.
Discussion of the Prior Art Precision-type sand casting (using core type sand such as zircon or silica) is known and has been used for at least 50 years in the commercial production of automotive castings, such as cylinder heads and blocks. This technique has many advantages, but it leaves certain features to be desired, such as increasing yield and improving the microstructure or surface finish of the casting, and increasing the speed of producing castings by such technique.
Risers, and to a lesser extent venting, have regularly been required in the molding system when sand casting aluminum. This is mAn~Ated to avoid shrinkage and pin holes in the solidifying regions. The risers serve as a molten reserve of aluminum that stays hotter to feed such - regions. Unfortunately such risers adversely affect yield of the process.
Such sand casting proceSses usually rely on gravity to feed molten metal to a runner system with the pressure head from the metal filling the sprue serving to provide a low level of pressurization for the metal in the runners. Due to the need to fill the risers during the pour, the cycle is slowed, allowing the molten temperature to drop and reach adverse temperature levels, particularly near the end of the mold filling. Thus, it is traditional - 21S93~1 to pour at higher metal temperatures to compensate for this aspect. This results in (i) a poorer surface finish, (ii) a poorer microstructure in the last metal to solidify, and (iii) poor production cycling.
The gravity runner system typically has abrupt changes in direction of sections of the runner system;
again, the metal must be poured at higher temperatures to maintain good fluidity over the slower cycle of the casting pour; this results in a flow that is somewhat turbulent.
Heat is readily transferred to the sand walls of the mold, often causing the sand particles to fracture, leading to poor surface finish for the metal casting. The higher pouring temperature tends to produce poorer metal microstructure in the regions last to solidify, producing a microstructure with wider dendritic arm spacing than desired.
Summary of the Invention This invention provides a technique and accompanying apparatus to solve the above problems while achieving increased yield, improved surface finish and microstructure, and faster cycling time for the casting process. The invention in a first aspect is a method of casting aluminum products comprising: (a) forming a precision sand mold, devoid of risers and/or vents, and a gating system consisting of a gravity feeding sprue and one - or more runners effective to carry molten metal from the _ _ sprue only to the bottom of the mold cavity; (b) planting a flow modifier in the gating system between the sprue and mold runner system to convert the flow into l~m; n~r quiescent flow; and (c) filling the gating system with molten aluminum metal at a rate in the range of 4-15 pounds per second as permitted by the l~m; n~r flow that more rapidly fills the mold and acts as an insulator to prevent a drop in temperature of the in-coming molten metal and thereby increase yield as well as m;n;m; zing cycle time.
A second aspect of this invention is an improved molding apparatus, comprising: (a) a precision sand mold devoid of risers and/or vents and having a mold cavity; (b) a runner system feeding the bottom of the mold at the largest metal regions of the mold cavity; (c) a sprue for gravity feeding of molten metal to the runner; (d) a flow modifier between the sprue and runners to effect laminar quiescent flow of the molten metal and to effect filtering of dross from the molten metal; and/or (e) a chill plate in the mold to at least control the solidification structure of the critical areas of the casting.
Brief Description of the Drawings Figure lA is a vertical sectional view of a mold and gating system to produce an automotive engine head casting, the mold and system e-mbodying the principles of this invention;
Figure lB is a perspective schematic illustration of the gating system of Figure lA showing the mold cavity broken away from the runner system;
Figure 2 is a reversed perspective illustration of the gating and mold system of Figure 1;
Figure 3 is an enlarged perspective illustration of the flow modifier utilized in Figures 1 and 2;
25Figure 4 is a graphical illustration of the relationship between aluminum flow rate and exposed surface --area of the flow modifier for providing l~m;n~r flow in _ _ _ distinction to filtratio~ and _ _ Figure 5 is a flow diagram illustrating the method steps of casting aluminum products according to the invention herein.
Detailed Description and Best Mode The gating system 10 (and Figure lB) must feed the largest to-be-cast metal masses 11 at the bottom of the mold cavity 12. This is necessary because of the conditions of directional solidification. For an automotive engine head casting, as shown in Figures 1 and 2, the casting cavity 12 desirably is oriented with the head deck 13 down; upright camtowers 14 are spaced at intervals 15 along the length of the head and bolt bosses 16 are aligned with the camtowers 14 to create enlarged metal mass zones which, for this casting, are the largest masses 11 adjacent the head deck. Concave com~bustion chamber roofs 17 are located between the camtowers 14, extending away from the head deck 13. The combustion cham~ber wall cavity and spark ignition sockets 19 as well as other cavities for valve train seats present complex internal shapes and demand optimum metal microstructure in the final casting.
The casting cavity is defined by the use of core-type sand (such as zircon or silica) walls 21; such sand walls are fabricated by conventional core making techniques.
The gating system 10 depends upon the gravity pressure head pushing the metal down a vertical sprue 23 to a horizontally extending runner system 27-28 that feeds the bottom 25 of the mold at the large mass zones 11. The sprue 23 should accept sufficient molten metal so that the filling of the mold can take place within m;nlml]m time and provide a pressure head sufficient to feed the casting while maintaining an excellent surface finish. For the --head casting cavity which here has an aluminum metal weight _ ~ _ of about 35-45 pounds, the sprue internal diameter is about 1-1/2 inches. To retain metal heat the sprue 23 can be insulated by a liner 26. The runner system may be split into two (or more) runner arms 27,28 to directly carry molten metal to the precise desired bottom locations of the mold cavity in a streamlined flow 29. Shallow ingates 30 (vertical channels) extend from the runners to connect the 35 top of the runner arms 27,28 to the large mass zones 11 at the bottom of the mold cavity. The runners have a cross-- 2159~91 sectional area of about six square inches which will taper to about three square inches for feeding the last of the ingates of the cylinder head example.
The sprue 23 has an enlarged base chamber 31 to facilitate transition of the molten metal to a horizontal flow; at the sides of the base cha-mber which connects to the entrance 32 to the runner system 27,28, is located a flow modifier 33 that extends across the flow area normal to the axis 29 of the flow. The flow modifier 33 is constructed to have a multitude of parallel equi-sized minute passages that promote l~m' n~r flow to the molten metal passing therethrough (see Figure 3). Such modifier may be fabricated of a high temperature extruded cellular ceramic, in various cell densities (about 300 cells per square inch). The modifier preferably has an open or porous area 36 that is about 50-80 percent of its total frontal exposed area 37. Such frontal exposed area 37 is preferably about 2-6 times the total choke area 38 of the gating system. Such porous area is also effective to filter, from the molten metal, slag dross and other non-metallic inclusions. Heretofore it has been believed that flow modifiers will lose their ability to filter molten metal at flow rates exceeding 4.0 pounds per second.
However, forming the modifier openings in squares or rectangles, and with the ratio of porosity to total area .5-.8, the modifier can convey molten aluminum at higher - rates with effective filtering of dross and slag (see _ _Figure 6). _ _ _ _ Such pouring rate permits an aluminum shot of about 75 pounds to be poured in 9 seconds (2 seconds to generate the head height and 7 seconds to deliver the molten metal through the sprue); see Figure 6.
To ensure enhanced metal microstructure at critical head surfaces, such as co-mbustion chambers, a cooled chill plate can be planted in the mold to define such surfaces.
GRAVITY PRECISION SAND CASTING OF
ALUMINUM AND ~QulvALENT METALS
Background of the Invention Technical Field This invention relates to using core sand for precision molding of metal castings, particularly aluminum, and more particularly to enhancement of metal yield, metal properties and quality features such as surface finish using such casting technique.
Discussion of the Prior Art Precision-type sand casting (using core type sand such as zircon or silica) is known and has been used for at least 50 years in the commercial production of automotive castings, such as cylinder heads and blocks. This technique has many advantages, but it leaves certain features to be desired, such as increasing yield and improving the microstructure or surface finish of the casting, and increasing the speed of producing castings by such technique.
Risers, and to a lesser extent venting, have regularly been required in the molding system when sand casting aluminum. This is mAn~Ated to avoid shrinkage and pin holes in the solidifying regions. The risers serve as a molten reserve of aluminum that stays hotter to feed such - regions. Unfortunately such risers adversely affect yield of the process.
Such sand casting proceSses usually rely on gravity to feed molten metal to a runner system with the pressure head from the metal filling the sprue serving to provide a low level of pressurization for the metal in the runners. Due to the need to fill the risers during the pour, the cycle is slowed, allowing the molten temperature to drop and reach adverse temperature levels, particularly near the end of the mold filling. Thus, it is traditional - 21S93~1 to pour at higher metal temperatures to compensate for this aspect. This results in (i) a poorer surface finish, (ii) a poorer microstructure in the last metal to solidify, and (iii) poor production cycling.
The gravity runner system typically has abrupt changes in direction of sections of the runner system;
again, the metal must be poured at higher temperatures to maintain good fluidity over the slower cycle of the casting pour; this results in a flow that is somewhat turbulent.
Heat is readily transferred to the sand walls of the mold, often causing the sand particles to fracture, leading to poor surface finish for the metal casting. The higher pouring temperature tends to produce poorer metal microstructure in the regions last to solidify, producing a microstructure with wider dendritic arm spacing than desired.
Summary of the Invention This invention provides a technique and accompanying apparatus to solve the above problems while achieving increased yield, improved surface finish and microstructure, and faster cycling time for the casting process. The invention in a first aspect is a method of casting aluminum products comprising: (a) forming a precision sand mold, devoid of risers and/or vents, and a gating system consisting of a gravity feeding sprue and one - or more runners effective to carry molten metal from the _ _ sprue only to the bottom of the mold cavity; (b) planting a flow modifier in the gating system between the sprue and mold runner system to convert the flow into l~m; n~r quiescent flow; and (c) filling the gating system with molten aluminum metal at a rate in the range of 4-15 pounds per second as permitted by the l~m; n~r flow that more rapidly fills the mold and acts as an insulator to prevent a drop in temperature of the in-coming molten metal and thereby increase yield as well as m;n;m; zing cycle time.
A second aspect of this invention is an improved molding apparatus, comprising: (a) a precision sand mold devoid of risers and/or vents and having a mold cavity; (b) a runner system feeding the bottom of the mold at the largest metal regions of the mold cavity; (c) a sprue for gravity feeding of molten metal to the runner; (d) a flow modifier between the sprue and runners to effect laminar quiescent flow of the molten metal and to effect filtering of dross from the molten metal; and/or (e) a chill plate in the mold to at least control the solidification structure of the critical areas of the casting.
Brief Description of the Drawings Figure lA is a vertical sectional view of a mold and gating system to produce an automotive engine head casting, the mold and system e-mbodying the principles of this invention;
Figure lB is a perspective schematic illustration of the gating system of Figure lA showing the mold cavity broken away from the runner system;
Figure 2 is a reversed perspective illustration of the gating and mold system of Figure 1;
Figure 3 is an enlarged perspective illustration of the flow modifier utilized in Figures 1 and 2;
25Figure 4 is a graphical illustration of the relationship between aluminum flow rate and exposed surface --area of the flow modifier for providing l~m;n~r flow in _ _ _ distinction to filtratio~ and _ _ Figure 5 is a flow diagram illustrating the method steps of casting aluminum products according to the invention herein.
Detailed Description and Best Mode The gating system 10 (and Figure lB) must feed the largest to-be-cast metal masses 11 at the bottom of the mold cavity 12. This is necessary because of the conditions of directional solidification. For an automotive engine head casting, as shown in Figures 1 and 2, the casting cavity 12 desirably is oriented with the head deck 13 down; upright camtowers 14 are spaced at intervals 15 along the length of the head and bolt bosses 16 are aligned with the camtowers 14 to create enlarged metal mass zones which, for this casting, are the largest masses 11 adjacent the head deck. Concave com~bustion chamber roofs 17 are located between the camtowers 14, extending away from the head deck 13. The combustion cham~ber wall cavity and spark ignition sockets 19 as well as other cavities for valve train seats present complex internal shapes and demand optimum metal microstructure in the final casting.
The casting cavity is defined by the use of core-type sand (such as zircon or silica) walls 21; such sand walls are fabricated by conventional core making techniques.
The gating system 10 depends upon the gravity pressure head pushing the metal down a vertical sprue 23 to a horizontally extending runner system 27-28 that feeds the bottom 25 of the mold at the large mass zones 11. The sprue 23 should accept sufficient molten metal so that the filling of the mold can take place within m;nlml]m time and provide a pressure head sufficient to feed the casting while maintaining an excellent surface finish. For the --head casting cavity which here has an aluminum metal weight _ ~ _ of about 35-45 pounds, the sprue internal diameter is about 1-1/2 inches. To retain metal heat the sprue 23 can be insulated by a liner 26. The runner system may be split into two (or more) runner arms 27,28 to directly carry molten metal to the precise desired bottom locations of the mold cavity in a streamlined flow 29. Shallow ingates 30 (vertical channels) extend from the runners to connect the 35 top of the runner arms 27,28 to the large mass zones 11 at the bottom of the mold cavity. The runners have a cross-- 2159~91 sectional area of about six square inches which will taper to about three square inches for feeding the last of the ingates of the cylinder head example.
The sprue 23 has an enlarged base chamber 31 to facilitate transition of the molten metal to a horizontal flow; at the sides of the base cha-mber which connects to the entrance 32 to the runner system 27,28, is located a flow modifier 33 that extends across the flow area normal to the axis 29 of the flow. The flow modifier 33 is constructed to have a multitude of parallel equi-sized minute passages that promote l~m' n~r flow to the molten metal passing therethrough (see Figure 3). Such modifier may be fabricated of a high temperature extruded cellular ceramic, in various cell densities (about 300 cells per square inch). The modifier preferably has an open or porous area 36 that is about 50-80 percent of its total frontal exposed area 37. Such frontal exposed area 37 is preferably about 2-6 times the total choke area 38 of the gating system. Such porous area is also effective to filter, from the molten metal, slag dross and other non-metallic inclusions. Heretofore it has been believed that flow modifiers will lose their ability to filter molten metal at flow rates exceeding 4.0 pounds per second.
However, forming the modifier openings in squares or rectangles, and with the ratio of porosity to total area .5-.8, the modifier can convey molten aluminum at higher - rates with effective filtering of dross and slag (see _ _Figure 6). _ _ _ _ Such pouring rate permits an aluminum shot of about 75 pounds to be poured in 9 seconds (2 seconds to generate the head height and 7 seconds to deliver the molten metal through the sprue); see Figure 6.
To ensure enhanced metal microstructure at critical head surfaces, such as co-mbustion chambers, a cooled chill plate can be planted in the mold to define such surfaces.
Claims (11)
1. A method of casting aluminum products, comprising:
(a) forming a precision sand mold devoid of at least one of risers and vents, and a gating system consisting of a gravity feeding sprue and one or more runners effective to carry molten metal from said sprue only to the bottom of the mold cavity;
(b) planting a flow modifier in said gating system between the sprue and mold cavity to convert said flow into laminar flow; and (c) filling said gating system with molten aluminum metal at an enhanced pour rate permitted by said laminar flow that more readily fills the mold and acts as a heat insulator to keep the incoming molten metal at a higher temperature level thereby to minimize cycle time and improve the yield of the casting process.
(a) forming a precision sand mold devoid of at least one of risers and vents, and a gating system consisting of a gravity feeding sprue and one or more runners effective to carry molten metal from said sprue only to the bottom of the mold cavity;
(b) planting a flow modifier in said gating system between the sprue and mold cavity to convert said flow into laminar flow; and (c) filling said gating system with molten aluminum metal at an enhanced pour rate permitted by said laminar flow that more readily fills the mold and acts as a heat insulator to keep the incoming molten metal at a higher temperature level thereby to minimize cycle time and improve the yield of the casting process.
2. The method as in claim 1, in which said mold has a chill plate effective to define the surfaces of critical casting areas.
3. The method as in claim 1, in which said runners directly feed the largest mass zones of said mold cavity.
4. The method as in claim 1, in which said modifier is constructed of a ceramic material having a cell density of about 300 cells/in2 and an exposed porous area appropriate for the pouring rate.
5. The method as in claim 1, in which said flow modifier is effective to filter dross, slag and non-metallic inclusions from said molten aluminum.
6. The method as in claim 1, in which said gating system is filled and poured within a time cycle of about 7 seconds or less for a typical 75 pound automotive head casting.
7. The method as in claim 1, in which said molten metal is filled in step (c) at a temperature of no greater than 1400°F.
8. The method as in claim 1, in which the aluminum metal is selected from the group of 356, 319 or other aluminum casting alloys.
9. An aluminum automotive head product produced by the process of claim 1.
10. An improved molding apparatus for casting aluminum products, comprising:
(a) a precision sand mold devoid of risers and/or vents;
(b) a runner system feeding the bottom of said mold at the largest metal mass zones of the mold cavity;
(c) a sprue for gravity feeding of molten metal to the runners;
(d) a flow modifier between said sprue and runners to effect laminar quiescent flow of the molten aluminium metal and to filter said molten metal of dross, slag and non-metallic inclusions; and (e) a chill plate in said mold to at least control the solidification structure of critical regions of the casting.
(a) a precision sand mold devoid of risers and/or vents;
(b) a runner system feeding the bottom of said mold at the largest metal mass zones of the mold cavity;
(c) a sprue for gravity feeding of molten metal to the runners;
(d) a flow modifier between said sprue and runners to effect laminar quiescent flow of the molten aluminium metal and to filter said molten metal of dross, slag and non-metallic inclusions; and (e) a chill plate in said mold to at least control the solidification structure of critical regions of the casting.
11. The apparatus as in claim 10, in which said modifier has an open porous area of 50-80 percent of the frontal area of said modifier.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US08/319,901 US5620044A (en) | 1994-10-07 | 1994-10-07 | Gravity precision sand casting of aluminum and equivalent metals |
| US08/319,901 | 1994-10-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2159391A1 true CA2159391A1 (en) | 1996-04-08 |
Family
ID=23244082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002159391A Abandoned CA2159391A1 (en) | 1994-10-07 | 1995-09-28 | Gravity precision sand casting of aluminum and equivalent metals |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US5620044A (en) |
| CA (1) | CA2159391A1 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3955168B2 (en) | 1999-10-29 | 2007-08-08 | 日信工業株式会社 | Method for manufacturing caliper body of disc brake for vehicle and caliper body |
| US6857462B2 (en) * | 2002-11-25 | 2005-02-22 | Honda Giken Kogyo Kabushiki Kaisha | High pressure die cast process |
| US6929053B1 (en) | 2004-05-26 | 2005-08-16 | General Motors Corporation | Mold fill method and system |
| US8702694B2 (en) * | 2005-11-23 | 2014-04-22 | Covidien Lp | Auto-aligning ablating device and method of use |
| ES2702767T3 (en) * | 2006-04-19 | 2019-03-05 | Howmet Corp | Sequential mold replenishment |
| CN102688990A (en) * | 2012-06-15 | 2012-09-26 | 上海嘉朗实业有限公司 | Aluminium alloy hydraulic motor shell gravity casting mould and manufacturing method thereof |
| CN104289675A (en) * | 2013-07-16 | 2015-01-21 | 天津航天机电设备研究所 | Bridge type multipoint synchronous pouring and casting mechanism for large castings |
| CN104550890A (en) * | 2014-12-26 | 2015-04-29 | 宁夏共享装备有限公司 | Pouring system for reducing mold filling speed in pouring gate |
| CN104985128B (en) * | 2015-07-22 | 2018-01-05 | 湖北亚钢金属制造有限公司 | One kind casting multi-laminate pours running gate system and technique |
| US20180029113A1 (en) * | 2016-07-29 | 2018-02-01 | GM Global Technology Operations LLC | Direct squeeze casting |
| CN113319254A (en) * | 2021-05-06 | 2021-08-31 | 北京鼎匠科技发展有限公司 | Pouring system for regulating and controlling flow velocity of liquid metal in each pouring section and pouring process thereof |
Family Cites Families (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US486327A (en) * | 1892-11-15 | And john w | ||
| US790202A (en) * | 1904-04-05 | 1905-05-16 | Jacob K Griffith | Method of manufacturing castings. |
| US1347168A (en) * | 1919-07-11 | 1920-07-20 | Andrew Lillie | Process of making molds |
| US1385201A (en) * | 1919-11-29 | 1921-07-19 | Doehler Die Casting Co | Casting apparatus |
| US1543657A (en) * | 1922-11-20 | 1925-06-23 | Bohn Aluminium & Brass Corp | Mold |
| US1948653A (en) * | 1932-03-14 | 1934-02-27 | Bohn Aluminium & Brass Corp | Semipermanent molding apparatus |
| US2233405A (en) * | 1938-12-27 | 1941-03-04 | Permold Co | Method of and apparatus for casting cylinder heads |
| DE1751621B2 (en) * | 1968-06-29 | 1973-04-19 | Robert Bosch Hausgerate GmbH, 7927 Giengen | COMPRESSORS FOR REFRIGERATING MACHINES |
| US3752221A (en) * | 1969-10-30 | 1973-08-14 | United Aircraft Corp | Mold apparatus for casting with downward unidirectional solidification |
| US4112997A (en) * | 1977-02-28 | 1978-09-12 | Hitchiner Manufacturing Co., Inc. | Metal casting |
| JPS5868454A (en) * | 1981-10-18 | 1983-04-23 | Nippon Kokan Kk <Nkk> | Bottom running ingot making method for steel |
| DE3368884D1 (en) * | 1982-05-20 | 1987-02-12 | Cosworth Res & Dev Ltd | Method and apparatus for melting and casting metal |
| FR2530742B1 (en) * | 1982-07-22 | 1987-06-26 | Dba | VOLUMETRIC SCREW COMPRESSOR |
| US4466785A (en) * | 1982-11-18 | 1984-08-21 | Ingersoll-Rand Company | Clearance-controlling means comprising abradable layer and abrasive layer |
| JPS59188080A (en) * | 1983-03-31 | 1984-10-25 | Mazda Motor Corp | Rotary compressor with turning sleeve |
| JPS6022087A (en) * | 1983-07-16 | 1985-02-04 | Nippon Piston Ring Co Ltd | Vane type rotary pump |
| GB2182393A (en) * | 1985-11-04 | 1987-05-13 | Ngk Insulators Ltd | Intermeshing screw pump |
| GB8529380D0 (en) * | 1985-11-29 | 1986-01-08 | Cosworth Res & Dev Ltd | Metal castings |
| US4726788A (en) * | 1986-07-28 | 1988-02-23 | Geppert Erwin F | Electrical receptacle |
| JPS6352744A (en) * | 1986-08-22 | 1988-03-05 | Foseco Japan Ltd:Kk | Method for setting ceramic filter in mold |
| US4842037A (en) * | 1987-06-10 | 1989-06-27 | Foseco International Limited | Metal casting patterns |
| US4736788A (en) * | 1987-07-28 | 1988-04-12 | Casteel Technology Associates, Inc. | Gating apparatus |
| IT1229927B (en) * | 1988-10-14 | 1991-09-16 | Cipelletti Alberto Cae | VANE PUMP. |
| US5072773A (en) * | 1990-11-13 | 1991-12-17 | Cmi International, Inc. | Mold and method for making variable hardness castings |
-
1994
- 1994-10-07 US US08/319,901 patent/US5620044A/en not_active Expired - Lifetime
-
1995
- 1995-09-28 CA CA002159391A patent/CA2159391A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US5620044A (en) | 1997-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3068185B2 (en) | Metal casting | |
| AU601315B2 (en) | Moulds for metal casting and sleeves containing filters for use therein | |
| US5620044A (en) | Gravity precision sand casting of aluminum and equivalent metals | |
| JPH0569082A (en) | Lost-form casting and manufacture thereof | |
| KR20090077949A (en) | Casting mould for casting a cast part and use of such a casting mould | |
| US4072180A (en) | Process and mould for casting multiple articles | |
| EP0738192B1 (en) | Method and equipment for feeding shrinkage voids in metal castings | |
| US3636605A (en) | Method of making forged valves from cast slugs | |
| US4809764A (en) | Method of casting a metal article | |
| CN218425441U (en) | Pouring system of crankcase | |
| US7140415B1 (en) | Method and apparatus for direct pour casting | |
| AU633154B2 (en) | Method of controlling the rate of heat extraction in mould casting | |
| CN114054672A (en) | Method for casting and forming QT500-14 material wind power base | |
| CN115710611B (en) | Casting method of template casting for large injection molding machine | |
| CN214768732U (en) | High-extension high-compactness casting mold for brake system bracket | |
| CN216729435U (en) | Novel foundry goods die cavity of vice valve body of ball valve | |
| CN211758335U (en) | Casting system for enhancing casting feeding | |
| CN218460786U (en) | Vermicular graphite cast iron cylinder cover gating system | |
| CN113426951A (en) | Casting method of nodular cast iron thin control arm | |
| CN115710611A (en) | Casting method of template casting for large-scale injection molding machine | |
| SU1668028A1 (en) | Method for making cast permanent magnets | |
| JPH08206814A (en) | Metallic mold casting method | |
| AU654308B2 (en) | Casting of metal objects | |
| CN115625319A (en) | Pouring system, preparation method and pouring method for aluminum alloy bracket castings | |
| SU900958A2 (en) | Stack-type casting mould |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |