Classifications

• • 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
  • B22C9/084—Breaker cores

Definitions

• the invention relates to a feed system for a casting with a feeder (head) and a tube-like body.
• feeders When producing molded parts in the foundry, liquid metal is poured into a mold. The volume of the filled material decreases during the solidification process. Therefore, so-called feeders, i.e. Open or closed spaces in or on the casting mold, used to compensate for the volume deficit when the casting solidifies and to prevent voids in the casting.
• the feeders are connected to the casting or to the endangered casting area and are usually arranged above or on the side of the cavity.
• the feeders are arranged approximately at the gate height and also equipped with a heat-insulating material or exothermic masses so that the melt in the feeder solidifies later than the casting itself. After solidification, the feeder remains connected to the casting, so that the residual feeder must then be separated.
• the clean and easy separation of the feeder from the casting is problematic in many cases. After the feeder has been disconnected, the cast surface must be regularly deburred and smoothed. This is a complex and correspondingly expensive operation, which can also damage the surface of the casting at the connection point with the feeder. So-called crushing cores (also called breaking edge, sand bar or constricting core) are often provided in order to reduce such damage and to make it easier to separate the feeder.
• the known feeders are either relatively complex in their construction or handling in the manufacture of the casting mold and / or do not ensure easy and precise separation of the residual feeder from the finished casting or require a relatively large attachment surface.
• the aim of the present invention was therefore to provide a feeder system which avoids the disadvantages of the prior art and is in particular of simple construction, can be easily attached or molded onto the casting mold, requires only small attachment surfaces and yet has a precisely positioned breaking edge directly on the casting for easy and safe separation of the residual feeder from the finished casting.
• feeder encompasses any form of feeders, feeder casings, feeder inserts and feeder caps as well as heating pads which are known in the prior art or are familiar to the person skilled in the art.
• the present invention is useful in principle for all types of feeders in which the tubular body can be arranged in the manner specified below.
• the present invention is suitable for so-called mini-feeders, which are conventionally molded on with crushing cores or with the aid of a spring mandrel.
• the feed system according to the invention consists of at least two parts. On the one hand is on the side facing away from the casting Side a feeder or feeder head is available, which provides a cavity for receiving the liquid metal during casting.
• a pipe-like body adjoins the casting, which, directly or indirectly, connects the cavity formed by the feeder head to the cavity of the casting mold.
• the tube-like body can have any length, wall thickness and diameter which is suitable in individual cases.
• the wall thickness will generally be between 0.1 mm and 10 mm, in particular between 0.3 mm and 5 mm, particularly preferably 0.3 mm to 0.5 mm. The optimum dimensions can be determined in individual cases on the basis of routine tests or are known to the person skilled in the art on the basis of his experience.
• the wall thicknesses also vary due to the material and can e.g. for sheet steel and when using a spring mandrel mini feeder are approximately 0.3 mm to 0.5 mm.
• the tube-like body has a length of between approximately 15 and approximately 300 mm, in particular between approximately 35 and approximately 100 mm.
• the length of the tube-like body is chosen so that at least the distance between the feeder (before molding, possibly on the mandrel) and the casting is bridged.
• the inside diameter of the tube-like body can in principle be chosen arbitrarily, the opening should be large enough to ensure the flow of the melt into or out of the feeder during the casting and solidification process.
• the diameter of the tube-like body is generally, but not necessarily, based on the inside diameter of the feeder, since according to one embodiment of the present Invention of the tube-like body in the feeder (head) is fitted or inserted. However, a different type of attachment to or in the feeder (head) is also possible.
• the tube-like body can have any cross-sectional shape, in particular a round, oval or quadrangular or polygonal geometry.
• the tube-like body is a tube with a substantially uniform cross section over the entire length.
• the ratio of wall thickness to the total diameter of the tube is preferably between about 1: 2 and 1: 200, in particular 1: 5 to 1: 120 and particularly preferably 1:10 to 1: 100.
• the ratio of length to total diameter of the tube is preferably between about 1: 4 and 15: 1, in particular 1: 1 and 6: 1.
• the conditions depend on the geometry of the feeder and the mold.
• the feeder or feeder head can be formed from any insulating and / or exothermic material known in the prior art in order to ensure that the melt in the feeder solidifies later than the casting itself.
• the feeder can be produced from the exothermic feeder masses disclosed in DE 199 25 167 by the same applicant.
• the tube-like body can be formed from any suitable material which has an appropriate strength and does not have any disruptive reactions to the casting to be fed. These materials are known to the person skilled in the relevant art and include, for example, metal, plastic, cardboard, ceramic or similar materials. According to a preferred embodiment, the tube-like body consists of a material similar to the casting program, such as aluminum or sheet iron.
• the tube-like body lies with the outer circumference closely on the feeder or feeder head and is preferably attached to the feeder (head) by means familiar to the person skilled in the art, e.g. by means of an adhesive such as hot glue or water glass, by a wedge or by means of a fit. It can also simply be plugged into the feeder (head).
• the tube-like body is movable relative to the feeder or feeder head and / or the casting or the hollow mold body at least within certain limits. This ensures, on the one hand, a particularly uncomplicated attachment of the feeder, and, on the other hand, optimal positioning of the breaking edge is brought about by the displacement between the feeder and the tube-like body or tube-like body and casting, which takes place during the molding or compression of the molding material.
• the distance between the tube-like body and the casting before molding can be easily adjusted so that after molding or compression of the Formforms the tube-like body forms an optimally positioned breaking edge, which is as close as possible to the finished casting.
• the tube-like body tapers towards the casting and forms a breaking edge directly at the transition to the casting mold or in the immediate vicinity.
• only a certain section, preferably the section facing the casting can have a taper or a narrowing of the (inner) diameter.
• the tube-like body thus serves on the one hand to provide an inflatable neck and on the other hand to provide a precise and firmly positioned breaking edge.
• the breaking edge is preferably provided as a constriction of the opening or the inner diameter at or in the vicinity of the end of the tube-like body facing the casting.
• the tube-like body does not taper towards the casting or has no tapered section. It can be advantageous to push the tube-like body, for example an essentially cylindrical tube, over a mandrel, in particular a spring or guide mandrel, until the end of the tube-like body facing the casting sits on the base of the dome close to the casting , A small gap is formed between the tube-like body and the (foot of the) cathedral. It has been shown that this gap, together with air pockets in this area which form during the molding, can also lead to the formation of an acceptable breaking edge.
• a mandrel in particular a spring or guide mandrel
• the position and shape of the breaking edge can be optimized by dimensioning the tube-like body, for example by using a relatively narrow tube with a small diameter or a corresponding arrangement of the feeder or feeder head, so that this after molding or Compression of the molding material quite close (but is not directly on the) casting.
• the feed system according to the invention furthermore comprises a mandrel, in particular a spring mandrel.
• the feeder connected to the tube is held up accordingly by the spring mandrel.
• the tube stands on the shape or on the beveled base of the spring mandrel.
• the feeder is guided downwards through the tube into the corresponding end position through the spring dome.
• the pipe remains firmly in the original position. This ensures that a defined breaking edge is provided directly on the casting.
• any core, mandrel or spring mandrel which seems suitable to the person skilled in the art can be used.
• the tube-like body can either grip completely over the spring mandrel or stand on its base. In both cases, a connection is made (directly or indirectly) between the mold cavity and the tube-like body.
• the tube-like body can be used as a spring mandrel or guide mandrel replacement.
• the feeder is guided over the tube-like body that stands on the mold. If necessary, centering is carried out via a fixed mandrel, which can be of different lengths.
• the fixed mandrel preferably has a maximum length of the tube-like body. In many cases, however, it can be advantageous for the fixed dome to be shorter than the tubular body and the latter is at least partially pushed over the fixed mandrel.
• the feeder then pushes over the tube-like body during compaction.
• the feeder is destroyed in the upper area by the tube-like body. The food fragments are embedded in the molding sand.
• the tube-like body must be set for each casting so that the distance between the feeder and the casting still leads to sufficient feeding. This distance will often be between 5 and 25 mm.
• the tube-like body can be open or closed at the top.
• the tubular body if it is open on the side facing away from the casting, can be supported by a relatively long mandrel, in which case the tubular body is preferably made of a solid material, such as sheet steel, e.g. with a material thickness of about 0.7 mm. But there are also other solid materials, such as plastic, e.g. PE, or ceramic, advantageous.
• the tube-like body is preferably perforated in the upper region in order to ensure good ignition of the feeder. There should be no holes or openings in the pipe-like body towards the casting, insofar as this would lead to the penetration of molding sand during molding.
• the tube-like body is not connected directly to the casting or the hollow mold body before the molding or compression of the molding material or stands on the spring arbor (if present).
• the feed system can be designed in such a way that the tube-like body moves toward the casting or hollow mold body during the molding or compression of the molding material.
• the tube-like body is relatively thin-walled, so that it can cut through the molded material to form a casting while it is being formed or compacted. This can be made easier by the fact that the tube-like body is provided with a kind of cutting edge at the end facing the casting, or its wall thickness decreases there or is particularly small.
• the feeder system is dimensioned and arranged opposite the casting in such a way that a defined breaking edge is formed on the tube-like body between the feeder and the casting when the spring travel is matched or the compression of the molding material has been completed.
• the tube-like body preferably has, on the one hand, a relatively thin mold wall which enables penetration through the molding material to the casting or to the hollow mold body.
• a wall thickness of the tubular body of approximately 0.05 to 1 mm, in particular 0.2 to 0.5 mm, using a solid material such as sheet steel, plastic or ceramic is preferably used.
• the tube wall must have sufficient stability so that it is not destroyed during the compression of the molding material so that there is no longer a feed-through connection between the hollow mold body and the feeder. Therefore, the preferred wall thickness of the tube-like body depends on the material used. Suitable wall thicknesses are familiar to the person skilled in the art depending on the material selected or can be optimized on the basis of routine tests.
• the cutting process is supported in that the tube-like body finds a stop or support in the feeder and is thus pressed together with the feeder or feeder head towards the casting.
• a stop is to be understood to mean a special shape on a wall, in particular an inner wall of the feeder or feeder head, which contacts the end of the tube-like body facing away from the casting, in punctiform or flat fashion, at least during the molding or compression of the molding material.
• the tube-like body can also be supported with respect to the feeder or feeder head by appropriate gluing, wedging or fitting between the tube-like body and feeder or feeder head, as already described for example in DE 100 59 481.6, or by a support point or a support surface which supports the tube-like body with respect to the feeder or feeder head at least after the molding material has been molded or compressed.
• the tube-like body preferably does not sit on the foot of the spring mandrel before the molding or compression of the molding material, but rather pushes itself forward to the foot of the spring mandrel during the compression of the molding material. According to the invention, it is also possible that the tube-like body in the absence of a spring cuts or pushes the mandrel independently to the casting or hollow mold.
• the feed system according to the invention can be attached and molded onto the casting molds very simply and universally, and ensures a reproducible and optimally positioned breaking edge, even when using a mandrel or spring mandrel. After shaping and, if necessary, removing the core or (spring) mandrel, the tube-like body remains in the shape.
• the feeder system can be assembled either at the factory or at the customer's mold.
• the feed system according to the invention makes other processes such as the use of a commercially available crushing core, e.g. of a croning crusher core to produce a suitable breaking edge.
• another aspect relates to the present Invention also a casting arrangement comprising the feed system defined above and the casting / the hollow mold (and a molding material) or a method for preparing a mold using the feed system according to the invention.
• the invention relates to the use of a tube-like body for forming an inflatable neck with a breaking edge in feeders for castings.
• FIG. 2 shows a feed system according to the invention with a tube-like body, which has a taper towards the casting;
• FIG. 3a shows a feeder system according to the invention with a tubular body before the molding or compression of the molding material
• 3b shows a feeder system according to the invention with a tube-like body after the compression of the molding material
• Figs. 4a and 4b illustrate a further embodiment of the feeder system according to the invention, the tube-like body having openings or holes in the part facing away from the casting.
• a conventional feeder 1 made of an exothermic and / or insulating mass is placed on the casting 4 via a spring mandrel 2. There is no optimal breaking edge designed for separating or knocking off the rest of the feeder.
• FIG. 2 shows a feed system according to the invention, a tube-like body 3 being guided over the spring mandrel 2 and tapering towards the casting 4.
• a breaking edge 5 is thereby formed.
• the tube-like body tapers towards the casting and sits on the base or base 6 of the spring mandrel.
• a feeder (head) 1 is placed on the tube, a hot-melt adhesive seam 7 being provided for sealing between the feeder and the tube circumference. After this The feeder assumes the position marked by rough hatching, the relative movement between the tube-like body and feeder taking place and the positioning of the breaking edge on the tube-like body relative to the casting remaining unchanged. This ensures optimal positioning of the breaking edge regardless of the final position of the feeder after molding.
• FIG. 3 shows a feeder system according to the invention, a projection or stop 8 for the tube-like body 3 being provided on the inner wall of the feed (head) 1.
• the tube-like body 3 tapers towards the casting or mold hollow body 4 and can cut through the molding material during the molding or compression of the molding material or advance towards the casting.
• the travel when compressing the molding material can be adjusted so that the . Forms breaking edge at the foot of mandrel 2 close to the casting. It is also possible that the tube-like body has no taper and is essentially cylindrical.
• 3a shows the feed system before the compression of the molding material, the end of the tubular body facing the casting not being seated on the base 9 of the spring mandrel or being connected directly to the casting or the hollow molding.
• FIG. 3b shows the feed system after the compression of the molding material, the tube-like body being connected directly to the molding hollow body or seated on the base 9 of the spring mandrel 2, if present, or on the casting.
• Figs. 4a and 4b show a further embodiment according to the invention, the tube-like body 3 having holes or openings 10 in the part facing away from the casting.
• the tubular body stands on the casting 4 before the molding material is molded or compressed.
• the feeder head 1 has deliberately been destroyed in the upper region 1 ', with a relative movement between the tube-like body 3 and the feeder head 1 taking place.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Continuous Casting (AREA)
• Hydroponics (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Devices For Post-Treatments, Processing, Supply, Discharge, And Other Processes (AREA)
• Surgical Instruments (AREA)
• Massaging Devices (AREA)
• Orthopedics, Nursing, And Contraception (AREA)

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• 2001
  • 2001-09-13 DE DE20115140U patent/DE20115140U1/de not_active Expired - Lifetime
  • 2001-11-02 DE DE50111827T patent/DE50111827D1/de not_active Expired - Lifetime
  • 2001-11-02 AU AU2002223665A patent/AU2002223665A1/en not_active Abandoned
  • 2001-11-02 ES ES01998419T patent/ES2280436T5/es not_active Expired - Lifetime
  • 2001-11-02 US US10/433,236 patent/US6904952B2/en not_active Expired - Lifetime
  • 2001-11-02 AT AT01998419T patent/ATE350181T1/de not_active IP Right Cessation
  • 2001-11-02 WO PCT/EP2001/012730 patent/WO2002043899A2/fr active IP Right Grant
  • 2001-11-02 JP JP2002545862A patent/JP4379856B2/ja not_active Expired - Fee Related
  • 2001-11-02 EP EP01998419.4A patent/EP1345716B2/fr not_active Expired - Lifetime
• 2005
  • 2005-06-06 US US11/145,798 patent/US7320355B2/en not_active Expired - Lifetime
• 2008
  • 2008-10-14 JP JP2008265811A patent/JP2009006401A/ja active Pending

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