US3216072A - Die casting method and apparatus - Google Patents

Die casting method and apparatus Download PDF

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Publication number
US3216072A
US3216072A US159025A US15902561A US3216072A US 3216072 A US3216072 A US 3216072A US 159025 A US159025 A US 159025A US 15902561 A US15902561 A US 15902561A US 3216072 A US3216072 A US 3216072A
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US
United States
Prior art keywords
core
casting
die
coating
parts
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
US159025A
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English (en)
Inventor
Alfred F Bauer
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.)
NL Industries Inc
Original Assignee
Nat Lead 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
Application filed by Nat Lead Co filed Critical Nat Lead Co
Priority to US159025A priority Critical patent/US3216072A/en
Priority to CH1377862A priority patent/CH387232A/fr
Priority to LU42745D priority patent/LU42745A1/xx
Priority to GB46681/62A priority patent/GB964307A/en
Application granted granted Critical
Publication of US3216072A publication Critical patent/US3216072A/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
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/101—Permanent cores
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D19/00—Casting in, on, or around objects which form part of the product
    • B22D19/0009—Cylinders, pistons

Definitions

  • This invention relates to a die casting method and apparatus for producing complicated die cast parts in which a core having a multiplicity of separable parts is required.
  • the coating is applied outside of the die casting machine by an appropriate device such as a metallizing gun and the applied coating, being under almost zero pressure, has little tendency to enter the parting line between the assembled parts of the collapsible core. Thus only a very small ridge, a few thousandths of an inch high, appears in the casting to show the line of demarcation between the core parts after they are removed from the finished piece.
  • collapsible cores have a relatively short life because they are worn and eroded by the chemical and thermal action and the high pressure of the casting metal. Thus even though the parts which make up the core fit very well and very closely when the core is new, a few hundred casting cycles may be sufficient to so erode and distort the parts that replacement becomes necessary.
  • the present invention provides a means for greatly increasing the life expectancy of the parts of a collapsible core.
  • the present invention makes it possible to anchor the core parts together as a complete and selfsustaining unit which can be related to the remainder of the die elements with the same precision that would be expected from a single die insert.
  • the parts of the core are so closely fitted and held that almost no flash enters between them in areas where no coating has been applied, and the division line, while visible in the completed casting, has a width and height of only one or two thousandths of an inch.
  • the primary object of the present invention is to provide a method and apparatus for die casting relatively complicated parts by which a plurality of separable die pieces are temporarily related into a single, protected core body for insertion into a die casting die.
  • Another object of the invention is to provide a method and apparatus for die casting relatively complicated parts by which a plurality of separable die pieces are temporarily related by means of a protective coating of metal which is transplanted by the casting operation from the die pieces to the castings so that the die pieces are easily withdrawn from the casting.
  • Another object of the invention is to provide a method and means for protecting and thus extending the life of the several parts of a collapsible die casting core.
  • FIG. 1 is an exploded top plan view of the parts included in a typical collapsible die casting core
  • FIG. 2 is an exploded perspective view of the parts shown in FIG. 1;
  • FIG. 3 is a perspective view of the parts shown in FIG. 2 in assembled relation;
  • FIG. 4 is a perspective view of the core parts after coating
  • FIGS. 5 and 6 are cross-sectional views of a completed casting indicating the removal sequence of the core parts
  • FIG. 7 is a somewhat diagrammatic longitudinal sectional view showing the relationship between the core parts and other die elements for making a casting.
  • FIG. 8 is a section on line 88 of FIG. 7.
  • a collapsible core is shown in top plan View in FIG. 1 and in perspective in FIG. 2, in each instance with the parts that will constitute the core in a disassembled condition.
  • a central, major core body 10 is provided, the base of which is shaped to be received in an ejector die part.
  • the manner of fixing the collapsible core in the die may be the same as is now known in the art. Usually this comprises a means to locate the core in a particular position in the die as well as some means to aflix it against lateral displacement.
  • the main core body 10 is provided with shoulders 12 on which the side pieces are supported, the side pieces being designated 14, 15 and 16. Suitable temporary locating devices such as pins 17 project from the shoulders 12 and are received in holes 18 in the base of the respective side core pieces.
  • the side core pieces may be made long or short, at the selection of the designer.
  • the side core pieces 14 and 16 include projections 20 which extend in a direction normal to the axis of the main core piece 10 (which will be the central axis of a resulting casting). These projections will cooperate with stationary die cores 22 and 23 (FIG. 7) to form intake passages for the engine cylinder in the resulting casting. Were it not for the collapsible core technique these passages would have to be formed by side cores entering at right angles to the axis of the die and leaving openings which would then be covered or closed in a subsequent operation.
  • the stationary core pieces 22, 23 and 26 project from the ejector half of the die in a known manner.
  • the collapsible core so far described dilfers from a conventional collapsible core for making the same part largely in that it substitutes the simple locating dowel pins 17 for a much more elaborate dove-tailing system which would ordinarily be used to attach the side pieces 14, 15 and 16 to the main or center core part 10.
  • the core is smooth on its exterior surface in accordance with known die making practice.
  • the center core part 10 in the form shown is provided with a boss 90 which will form a recess in the top of the cylinder casting, and may be of any desired top configuration.
  • FIGS. 1, 2, 3 and 4 the core pieces so far described are shown first in separated relationship in FIGS. 1 and 2 and in assembled relationship in FIG. 3. When the pieces are put together as shown in FIG. 3, they are then coated as shown in FIG. 4.
  • the coating (designated applied to the assembly is preferably a metallic coating having properties which are of special utility in the resulting casting, although in accordance with the present invention the coating may be of the same com position as the metal which will ultimately be cast around it in which case the coating performs only the functions of retaining the collapsible core elements in assembled relationship and protecting them against deteriorating during the casting cycle.
  • the protective coating 35 be of a metal which will form a highly wear resistant interior surface for that portion of the cylinder swept by the engine piston. It is known that iron alloys are satisfactory for this purpose. Therefore, one coating which may be applied to carry out the present invention may consist of an iron alloy deposited by a metallizing gun which will result in a mixture of the iron alloy and iron oxide. If the coating as applied by making several passes of the metallizing gun axially of the assembled core parts while the core parts are rotated in an appropriate fixture, it will be found that a desirable stratification occurs and that the grain structure of the coating is elongated in the axial direction.
  • the coating may be made thicker at one end of the cylinder than the other to impart a physical reinforcement thereto, or it may be varied in composition from end to end to be more refractory in the combustion chamber end of the cylinder, and more retentive of oil in the lower or crankcase end.
  • the coating 35 may be applied also by dipping the assembled core parts, or by brushing a suitable material in place. These techniques are applicable where the coating material is capable of suspension in a liquid to form a workable slip. The applied slip may then be fired or cured to form a body which will not wash off during the casting step and which will protect the core parts from the casting metal. Regardless of the method of application of the coating material, whether it be brushing, spraying or dipping, the application pressure is almost zero and the coating material is not forced between the elements of the collapsible core. The penetration will depend, of course, on the fits between parts, greater penetration occurring if the parts are loosely fitted than if they are closed. Penetration will also depend on the degree that the coating material wets the core pieces and thus to some extent on the surface characteristics of the core elements themselves. It is desirable, therefore, that the core elements be assembled with rather close tolerances so that the joints between them are not wide.
  • the coating has a greater degree of adhesion to the casting than to the smooth core pieces on which it was initially formed or deposited.
  • the thickness of the coating 35 may be varied.
  • the lower limit of thickness depends only on two factors; first, the coating must be thick enough to hold the assembled core parts together in cooperation with the remaining support elements such as the dowel pins 17; and secondly, it must be thick enough to resist the washing effect of the molten metal entering the die during the casting operation.
  • the coated core is put into the die and the shot is made.
  • the core is then ejected with the casting.
  • the coating 35 will have become adhered to the casting and will have transplanted from the core, as taught in my said copending application Serial No. 811,611.
  • the center core part 10 is removed first, which separates the dowelled connection between this element and the side parts 14, 15 and 16, which can then be taken out sequentially as indicated in FIGS. 5 and 6 of the drawings.
  • Castings made in accordance with the present invention show that the coating material enters between the parts of the core for only a few thousandths of an inch, leaving small ridges or raised lines in the casting. These ridges are readily honed out of an engine cylinder but may, of course, be left unfinished in some castings where their presence is unimportant as in a valve body, for example.
  • the presence of the coating material assures that none of the casting metal can enter as flash into the spaces between the core parts while flash causes rapid deterioration in many collapsible cores. Further, the coating material prolongs the life of the core parts by preventing direct contact between the casting metal and the core parts.
  • a method of die casting comprising assembling a plurality of separable and re-usable core parts, applying a thin coating comprising a mixture of metal and metal oxides over selected areas of the assembly of core parts including at least some of the joining lines between the core parts said coating having a thickness at least suflicient to hold said core parts in assembled relation prior to insertion into a die and to maintain its integrity during a subsequent casting operation, inserting the coated assembly as a unitary core piece into a die casting die with the coated surface exposed to the die cavity, casting metal into the die cavity under high pressure to cause the casting metal to bond to the coating with a bond strength higher than the strength of the adhering force between the coating and the assembly of core parts, ejecting the casting, and finally removing the core parts leaving the coating material adhered to the casting.
  • Core apparatus for making high pressure die casting comprising, the combination of a plurality of separable and re-usable core elements which when related define at least a part of a die cavity, and an integral, continuous protective metallic coat surrounding said separable core elements and covering at least the majority of all lines of separation therebetween, said coat being interposed between said core elements and the remainder of the die cavity for contact with molten metal to be injected into said die cavity and said coating having an exposed surface of such rough, irregular and porous nature as to be removed from said core element and adhered to the die casting upon completion of casting and withdrawal of said core elements.
  • At least one of said core elements includes a lateral protrusion for forming an off-set in a casting, and said coating covers said protrusion.
  • Apparatus for making a composite high pressure die casting with a lining having special utility therein comprising, an assembled plurality of separable core elements including a major element and at least one minor element, one of said core elements having a laterally extending projection which cooperates with other die portions to form an off-set opening, means to temporarily fasten said minor elements on said major element, said elements when assembled forming a portion of a die cavity, an integral continuous mechanically applied metallic coating covering at least the major portion of the line of separation between said major and minor core elements and covering said lateral projection, said coating being interposed between said core elements and said die cavity and being of such nature as to prevent the entry of molten metal as flash between said core elements in the covered area, said coating presenting a relatively rough surface to said die cavity whereby the coating interlocks with and mechanically bonds to the casting upon removal of said core elements, said coating thus acting to cover the interior of at least the oil-set portion of the casting.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)
US159025A 1961-12-13 1961-12-13 Die casting method and apparatus Expired - Lifetime US3216072A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US159025A US3216072A (en) 1961-12-13 1961-12-13 Die casting method and apparatus
CH1377862A CH387232A (fr) 1961-12-13 1962-11-22 Procédé de coulée sous pression et appareil pour sa mise en oeuvre
LU42745D LU42745A1 (fr) 1961-12-13 1962-11-23
GB46681/62A GB964307A (en) 1961-12-13 1962-12-11 Die casting method and apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US159025A US3216072A (en) 1961-12-13 1961-12-13 Die casting method and apparatus

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US3216072A true US3216072A (en) 1965-11-09

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US159025A Expired - Lifetime US3216072A (en) 1961-12-13 1961-12-13 Die casting method and apparatus

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US (1) US3216072A (fr)
CH (1) CH387232A (fr)
GB (1) GB964307A (fr)
LU (1) LU42745A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3401026A (en) * 1966-01-19 1968-09-10 Gen Motors Corp Method of forming a bimetallic article
US3860058A (en) * 1973-11-05 1975-01-14 Ford Motor Co Method of forming dimensional holes in the wankel rotor housing electroform
US3864815A (en) * 1973-12-10 1975-02-11 Nl Industries Inc Method of making a lined die casting by employing a transplant coating
US3886637A (en) * 1971-11-17 1975-06-03 Chromalloy American Corp Method of producing heat treatable titanium carbide tool steel coatings on cylinders of internal combustion engines
US4303221A (en) * 1980-11-14 1981-12-01 The Bendix Corporation Core pin for making a plastic connector shell having an internal keyway
US5547630A (en) * 1991-10-15 1996-08-20 Callaway Golf Company Wax pattern molding process
US20030139220A1 (en) * 2001-12-26 2003-07-24 Callaway Golf Company Magnetized core with pneumatic release system for creating a wax mold for a golf club head
US20100113169A1 (en) * 2007-04-10 2010-05-06 Ryu Choong O Mold for manufacturing composite drive shaft and composite drive shaft manufactured using the mold

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1195303A (en) * 1916-08-22 Leon weiss
US1348982A (en) * 1919-06-07 1920-08-10 Valley Mould Anl Iron Corp Collapsible core-bar
US1561287A (en) * 1923-10-20 1925-11-10 Doehler Die Casting Co Method and apparatus for die casting
US2903375A (en) * 1956-08-08 1959-09-08 Renault Method of coating a mould for use in a foundry
GB841891A (en) * 1956-08-08 1960-07-20 Renault Improved method of preparing foundry moulds
FR1248693A (fr) * 1959-01-02 1960-12-23 Aluminum Co Of America Articles bimétalliques moulés
GB873012A (en) * 1959-01-02 1961-07-19 Aluminum Co Of America Cast bimetallic articles
US3083424A (en) * 1959-05-07 1963-04-02 Nat Lead Co Method for producing coated die castings

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1195303A (en) * 1916-08-22 Leon weiss
US1348982A (en) * 1919-06-07 1920-08-10 Valley Mould Anl Iron Corp Collapsible core-bar
US1561287A (en) * 1923-10-20 1925-11-10 Doehler Die Casting Co Method and apparatus for die casting
US2903375A (en) * 1956-08-08 1959-09-08 Renault Method of coating a mould for use in a foundry
GB841891A (en) * 1956-08-08 1960-07-20 Renault Improved method of preparing foundry moulds
FR1248693A (fr) * 1959-01-02 1960-12-23 Aluminum Co Of America Articles bimétalliques moulés
GB873012A (en) * 1959-01-02 1961-07-19 Aluminum Co Of America Cast bimetallic articles
US3083424A (en) * 1959-05-07 1963-04-02 Nat Lead Co Method for producing coated die castings

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3401026A (en) * 1966-01-19 1968-09-10 Gen Motors Corp Method of forming a bimetallic article
US3886637A (en) * 1971-11-17 1975-06-03 Chromalloy American Corp Method of producing heat treatable titanium carbide tool steel coatings on cylinders of internal combustion engines
US3860058A (en) * 1973-11-05 1975-01-14 Ford Motor Co Method of forming dimensional holes in the wankel rotor housing electroform
US3864815A (en) * 1973-12-10 1975-02-11 Nl Industries Inc Method of making a lined die casting by employing a transplant coating
US4303221A (en) * 1980-11-14 1981-12-01 The Bendix Corporation Core pin for making a plastic connector shell having an internal keyway
US5547630A (en) * 1991-10-15 1996-08-20 Callaway Golf Company Wax pattern molding process
US20030139220A1 (en) * 2001-12-26 2003-07-24 Callaway Golf Company Magnetized core with pneumatic release system for creating a wax mold for a golf club head
US6978976B2 (en) * 2001-12-26 2005-12-27 Callaway Golf Company Magnetized core with pneumatic release system for creating a wax mold for a golf club head
US20060103049A1 (en) * 2001-12-26 2006-05-18 Maurice Duquette Magnetized Core with Pneumatic Release System for Creating a Wax Mold for a Golf Club Head
US20100113169A1 (en) * 2007-04-10 2010-05-06 Ryu Choong O Mold for manufacturing composite drive shaft and composite drive shaft manufactured using the mold
US8459978B2 (en) * 2007-04-10 2013-06-11 Choong O Ryu Method for manufacturing a composite drive shaft manufactured using mold

Also Published As

Publication number Publication date
CH387232A (fr) 1965-01-31
GB964307A (en) 1964-07-22
LU42745A1 (fr) 1963-01-23

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