US3178782A - Vacuum die casting of molten metals - Google Patents

Vacuum die casting of molten metals Download PDF

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Publication number
US3178782A
US3178782A US173287A US17328762A US3178782A US 3178782 A US3178782 A US 3178782A US 173287 A US173287 A US 173287A US 17328762 A US17328762 A US 17328762A US 3178782 A US3178782 A US 3178782A
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US
United States
Prior art keywords
die casting
valve
vacuum
metal
shot well
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.)
Expired - Lifetime
Application number
US173287A
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English (en)
Inventor
Foster C Bennett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL288985D priority Critical patent/NL288985A/xx
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Priority to US173287A priority patent/US3178782A/en
Priority to GB5634/63A priority patent/GB971679A/en
Application granted granted Critical
Publication of US3178782A publication Critical patent/US3178782A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/30—Accessories for supplying molten metal, e.g. in rations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/14—Machines with evacuated die cavity

Definitions

  • vacuum die casting or vacuum as used herein and as is understood in the die casting art means a die casting process wherein subatmospheric pressures are applied to the shot well, runner and mold cavity of a die casting machine thereby serving to pull a molten metal shot into the mold.
  • the vacuum ranges from only a little below atmospheric, i.e. from a maximum of about 27 or 28 inches mercury absolute, to about 1 to 2 inches mercury absolute or less.
  • the present invention comprises a valve mounted on the intake of a large bore suction tube of a vacuum die casting machine, which tube is immersed in a pot of molten metal.
  • This valve is operated in a predetermined controlled cycle in cooperation with the action of the die casting machine.
  • FIGURE 1 is a schematic view, partly in section of one embodiment of the valve assembly of the present invention mounted on a conventional plunger type vacuum die casting machine.
  • FIGURE 2 is a fragmentary view, partly in section, showing a second embodiment of the valve assembly of the present invention mounted on a similar vacuum die casting apparatus.
  • valve assembly 11 is positioned so as to cooperate with the open end 12 of suction tube 13 of vacuum die casting apparatus 14.
  • the other end of suction tube 13 is restricted into an orifice 5 at its junction with the cylindrical shot well 16 of the die casting machine 14.
  • the suction tube 13 is rigidly aflixed to the side wall 17 of shot well 16 and establishes communication into shot well 15.
  • the main portion of this suction tube 13 will be of a large bore, i.e. having an interior cross-sectional diameter of from about /2 inch to about 3 inches.
  • a combination gasket and gas pressure seal 18 of thermally insulating material, e.g. metal covered asbestos, is positioned between the suction tube 13 and side wall 17 of shot well 16 at this junction.
  • the suction tube 13 and gasket 13 can be held tightly in place against the side wall 17 of shot well 16 by means of a C-clamp 19 so as to form a liquid and pressure tight seal between these members.
  • the lower arm 28 of C-clamp 19 is divided and slides around the outside suction tube 13 below a projecting ring 21 integral to tube 13.
  • the stem 22 of the clamp also is divided so as to slide over the outside of shot Well 16.
  • the upper arm 23 of clamp 19 is fitted with a threaded opening 24 near its end 25.
  • A. thumb screw 26 is screwed through opening 24 and is tightened against the wall 17 of shot well 16 whereby the lower clamp arm 20 exerts pressure against ring 21 thereby holding the suction tube 13 and gasket 18 tightly against the wall 17 of shot well 16.
  • Piston 27 slidably moves within and along the bore of the shot well 17 and conventionally is positioned and held in place by a vacuum cap 28 affixed to the end of the shot well 16. A pressure-tight seal between the cap 28 and both the shot well 16 and piston 27 is assured through use of conventional G-rings 29 or other seals.
  • the valve assembly 11 comprises a valve head 30 mating with a valve seat 31 in the open end 12 of suction tube 13.
  • the valve head 30 is mounted on a valve stem 32.
  • Valve stem 32 in turn is attached to the bottom cross rod 33 of yoke assembly 34.
  • the yoke assembly 34 is attached by means of a rod 35 affixed to the upper yoke cross rod 36 of yoke assembly 34 to an air-driven reciprocating driving means 37
  • the valve head 30 is shown to bee frustum and is fastened onto the valve stem 32 by means of a nut 38 mating with the threaded end portion 39 of the valve stem 32.
  • this valve head 30 can be of diverse shapes; e.g. the valve head can be round-bottomed. Also, it can be welded, press fitted or otherwise fastened onto the valve stem 32.
  • the angle of taper of the valve head 30 and curvature of valve seat 31 should be great enough to avoid wedging of these members upon impact.
  • this angle as measured from the longitudinal axis of the valve stem to the tapered surface, at a minimum is about For those valve assemblies wherein the valve head is curved and valve seat is tapered, this same angular relationship holds true.
  • the mold, runner and shot well of a vacuum die casting machine are evacuated in a conventional manner, the valve at the end of the suction tube immersed in a pot of molten metal 41 to be metered being closed and the injection piston being adjacent the vacuum cap at the end of the shot well.
  • the valve at the end of the suction tube is opened for a timed interval whereupon a given quantity of metal is drawn into the shot well.
  • the actual amount of metal transferred into the shot Well for a particular casting operation can be accurately controlled by varying the mount of vacuum present in the apparatus and/ or changing the time intervalthat the valve is open.
  • the valve is closed, and, in a plunger type 7 machine, the plunger is activated thereby injecting the tion of the valve head on the stem 32 is reversed; i.e.'
  • the larger diameter base of the frustum is within the suction tube 13 and the valve action is reversed.
  • valve is activated by positive mechanical means rather than by gravity or spring motion.
  • positive mechanical means rather than by gravity or spring motion.
  • the valve assembly is activated through an automatic timer, e.g. an interval timer, thereby assuring precise control of the apparatus and automatic transfer of reproducibly constant predetermined quantities of metal to the shot well;
  • the valve is activated by an. air driven piston-cylinder, device 37 through a yoke and rod arrangement. It is apparent that the valve assembly can be operated by any of a wide variety of devices producing reasonably reciprocating linear motion.
  • the depicted air driven device is one preferred means since it is simple, easily and accurately con- I,
  • valves differing in construction and design from those described herein can be used as is apparent to one skilled in the art.
  • the size of the restraining orifice 15 which forms the l port whereby communication is established between suction tube 13 and shot well 16 can be of a given predetermined size so as to give a metal flow into the shot well of a desired controlled velocity.
  • the materials of construction to be employed for the valve assembly are those that have the requisite strength, stability of temperature and erosion and corrosion resistance to stand up in the presence of the molten metal being moved.
  • magnesium i.e. magnesium and magnesium based alloys containing at least about 70 percent by weight magnesium
  • chrome steels such as 430 stainless, for example, are satisfactory for the surfaces contacting the molten metal.
  • molten aluminum i.e. aluminum and aluminum basedalloys containing at least about 70 percent by weight aluminum
  • the valve assembly can be fabricated from steel having a refractory coating with hearing surfaces being coated with or constructed from titanium diboride, zirconium diboride or other construction material inert to molten aluminum. I
  • valve head surface Either the valve head surface, valve seat surface or.
  • the plunger is then returned to its The apparatus now is ready for anmetal into the die. original position. other cycle.
  • valve operation is carried out in a similar time cycle, this cycle again being coordinated with die casting machine operation. 7 7
  • Each cycle may be started manually when a die casting machine is cleared and is ready for another metal shot or it may be started automatically with suitable safeguards to prevent premature, late or double metal discharge.
  • a vacuum die casting machine for molten metals the improvement in combination therewith which comprises; providing a large bore suction tube having an interior cross-sectional diameter of from about /2 inch to about 3 inches rigidly attached by one end to the cylindrical side wall of the shot well of a die casting machine and establishing communication into said shot well, said suction tube being restricted into an orifice at its junction with said shot well, a combination gasket and gas pressure seal positioned between the suction tube and the side wall of said shot well at the junction of these members, said suction tube having a valve seat at its open end opposite the of said yoke assembly to a positive mechanical drive means, said mechanical drive means connected to and activated by an automatic timer thereby opening and closing said valve in accordance with a predetermined, planned program thereby to introduce reproducibly constant predetermined quantities of molten metal to said 5 shot well.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
US173287A 1962-02-14 1962-02-14 Vacuum die casting of molten metals Expired - Lifetime US3178782A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
NL288985D NL288985A (enrdf_load_html_response) 1962-02-14
US173287A US3178782A (en) 1962-02-14 1962-02-14 Vacuum die casting of molten metals
GB5634/63A GB971679A (en) 1962-02-14 1963-02-12 Process for the production of metal castings and apparatus therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US173287A US3178782A (en) 1962-02-14 1962-02-14 Vacuum die casting of molten metals

Publications (1)

Publication Number Publication Date
US3178782A true US3178782A (en) 1965-04-20

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US173287A Expired - Lifetime US3178782A (en) 1962-02-14 1962-02-14 Vacuum die casting of molten metals

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US (1) US3178782A (enrdf_load_html_response)
GB (1) GB971679A (enrdf_load_html_response)
NL (1) NL288985A (enrdf_load_html_response)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3529657A (en) * 1967-10-17 1970-09-22 Harry R Bucy Vacuum filled mold
US4476911A (en) * 1980-11-03 1984-10-16 Maschinenfabrik Muller-Weingarten A.G. Diecasting method for producing cast pieces which are low in gas, pores and oxides, as well as diecasting machine for implementing the method
US5407000A (en) * 1992-02-13 1995-04-18 The Dow Chemical Company Method and apparatus for handling molten metals
JP2013022621A (ja) * 2011-07-21 2013-02-04 Honda Motor Co Ltd 溶湯の供給方法及びその装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3309504A (en) * 1964-08-24 1967-03-14 Combustion Eng System for heating chromatographic columns

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2137764A (en) * 1936-03-19 1938-11-22 Wagner Karl Friedrich Apparatus for casting metal under pressure
US2210544A (en) * 1938-04-18 1940-08-06 Electric Storage Battery Co Casting
US2243425A (en) * 1937-05-08 1941-05-27 Rossi Irving Casting of metals and/or metal alloys and more particularly to a method of maintaining a uniform rate of flow of the molten mass into the mold or chill
US2618477A (en) * 1949-02-11 1952-11-18 Aluminum Co Of America Metal transfer system
US2799066A (en) * 1954-01-12 1957-07-16 Morgenstern Method of and apparatus for die casting under vacuum
US2904861A (en) * 1957-05-31 1959-09-22 Package Machinery Co Apparatus for and method of die casting under vacuum
US3032841A (en) * 1957-03-08 1962-05-08 Edmund Q Sylvester Methods and apparatus for casting metal
US3093871A (en) * 1960-07-15 1963-06-18 British Oxygen Co Ltd Die casting and moulding machine

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2137764A (en) * 1936-03-19 1938-11-22 Wagner Karl Friedrich Apparatus for casting metal under pressure
US2243425A (en) * 1937-05-08 1941-05-27 Rossi Irving Casting of metals and/or metal alloys and more particularly to a method of maintaining a uniform rate of flow of the molten mass into the mold or chill
US2210544A (en) * 1938-04-18 1940-08-06 Electric Storage Battery Co Casting
US2618477A (en) * 1949-02-11 1952-11-18 Aluminum Co Of America Metal transfer system
US2799066A (en) * 1954-01-12 1957-07-16 Morgenstern Method of and apparatus for die casting under vacuum
US3032841A (en) * 1957-03-08 1962-05-08 Edmund Q Sylvester Methods and apparatus for casting metal
US2904861A (en) * 1957-05-31 1959-09-22 Package Machinery Co Apparatus for and method of die casting under vacuum
US3093871A (en) * 1960-07-15 1963-06-18 British Oxygen Co Ltd Die casting and moulding machine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3529657A (en) * 1967-10-17 1970-09-22 Harry R Bucy Vacuum filled mold
US4476911A (en) * 1980-11-03 1984-10-16 Maschinenfabrik Muller-Weingarten A.G. Diecasting method for producing cast pieces which are low in gas, pores and oxides, as well as diecasting machine for implementing the method
US5407000A (en) * 1992-02-13 1995-04-18 The Dow Chemical Company Method and apparatus for handling molten metals
JP2013022621A (ja) * 2011-07-21 2013-02-04 Honda Motor Co Ltd 溶湯の供給方法及びその装置

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NL288985A (enrdf_load_html_response)
GB971679A (en) 1964-09-30

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