DE1957012A1 - Process for the production of molds from preformed plates - Google Patents

Description

45 Osnabrück ₃ November 12, 1969

MDSERSTRASSE 2O / 24 DB / Ka

PRES SED STE EL FIS HER LIMITED
C owley, Oxford , England

Process for the production of casting molds from preformed plates

The invention relates to a method for producing casting molds using preformed plates, in particular for the production of vacuum forming tools.

D & .ÜV process for producing a mold according to the invention is characterized in that the plate is so inserted into a casting box, that the imaged on the GußstücV "side upward and their rear countries ^T iodines of the box facing the space between thorn bottom of the plate and the bottom of the box and r'ui '^ z around the plate is filled with plastic foam, the ^ uin least partially in the form of a closed-pore or in' substantial ', esohlossenporigon foam-forming approach

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is introduced into the box and fills at least a part of the space and can escape through openings in the plate, which is through one or more openings in the The plate and any excess foam that has passed over around it is trimmed to adapt to its surface Casting compound is introduced into the casting box and the casting is removed from the box after it has solidified or set.

The casting or molding box expediently has in a manner known per se for the purpose of easy trimming of the excess Foam foldable or movable sides.

The space between the bottom of the plate and the bottom of the box can be completely matched by the Foam-forming approach should be filled with foam / in which pail the plate should be secured in its position. Instead, the interspace can also be made up of a mixture of discrete particles moistened with a resinous adhesive expanded or foamed plastic are filled 3 which is stuffed into the space in between. Then can the foam-forming approach around and through the plate Any holes provided in the plate - can be made in the box, where it can be used to fill in the below and to the Edges of the panel can foam up the remaining space. In this case, the plate is normally no longer required to be secured in the box. It can simply rest on top of the mixture. In addition, the

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Turning such a mixture in cases where the preformed Plate has a large surface or is easily subject to deformation for other reasons, the danger of warping j caused by the swelling of a foam-forming approach underneath a fixed plate could.

If the casting is to form a vacuum forming tool, can Appropriate openings can be provided in the cast by, for example, rods and / or tubes prior to introduction of the casting compound in the box. In this case, the plate is provided with corresponding small openings. Through which the Rods and / or tubes pass through.

The foam-forming approach can expediently consist of a mixture which, in reaction, is closed-cell urethane foam that can be trimmed with a knife or a rough saw. The discrete particles of plastic can be made from Expanded polystyrene beads are made and the resinous adhesive expediently consists of a mixture of 180 grams Lankro G 600, 120 grams P.A.B. 1 and 0-9 grams of tin octate.

The plate and the surface of the foam are expediently coated with a separating substance consisting of a silicone-based one established connection can exist, for example under / Sindeisbezeichen "Ambersil" on the market is, and is applied by spraying.

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AttUÄiiO OAS

BATH ORIGINAL.

195701Z

The casting compound can typically consist of refractory concrete, plaster of paris or a suitable synthetic resin or material.

The invention creates a simple and economical process z-ur production of a casting mold with a surface corresponding to a preformed plate, and it goes without saying that such preformed plates are often readily available from a prototype. Such preformed panels can often have different holes. The invention allows easily forming the plate surface in the mold, without any special precautions regarding the To hit holes. Through the closed-cell plastic foam or the bound discrete particles made of expanded or foamed plastic can cover the whole of the plate when the casting compound is introduced into the box Fully supported.

Further features of the invention emerge from the claims and the following description of an embodiment of the subject matter of the invention in conjunction with the drawing, which shows a vertical cross section through a casting mold made according to the invention and inserted in the box.

A molding or casting box 11 with sides 12 which can be folded or folded down or moved is arranged on a sheet steel floor. A preformed sheet steel plate 14 with an opening 15 and small openings 16 is by means of brackets 17, which on

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the plate l4 and the bottom 13 are attached by welding, firmly attached in the box 11.

A suitable amount of a foam-forming formulation consisting of a mixture which in reaction forms a closed-cell urethane foam is poured into the box 11 and forms the urethane foam 18, which fills the space between the plate Ik and the bottom of the box 11, through the holes 15 and ίβ escapes and rises above the plane of the plate 14 in the areas around the plate.

The sides 12 of the box 11 are now removed and the foam that has escaped through the openings 15 and 1 (5 is, as can be seen from the drawing, trimmed flush with the surface of the plate Ik , while the over the edges of the plate 14 to this foam 18, which has risen around it, is cut to form a flat, suitably shaped contour that is adapted to the surface of the plate 11. The contour design is incompatible with the intended use of the molded part to be poured. ;,

-? i the example shown are in the foam 18 through Ήο holes Io steel rods provided in '1 plate l'f 19 inserted, be pushed onto the tube 20 in such a way that

canals arise in the Gußst'ick, which its advance "; alrs Vakuumformv / Erkzeu ": enable. The tubes 20 can

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by a lump of petroleum jelly opposite the bars be supported. Optionally, the rods 19 can also be bent slightly so that they are connected to the inner walls of the tube 20 are resiliently in contact.

The sides 12 of the box 11 are then reattached and the exposed areas of the panel 1H and foam 18 are sprayed with the release agent "Ambersil" (R).

A cast mix of refractory concrete, which _{may contain "Trimor (} Mideast" (R)), is poured into box 11 and then vibrated to remove entrapped air removed from the box 11 and the rods 19 and the tubes 20 are pulled out.

In another embodiment of the invention, the mixture of expanded polystyrene beads moistened with an adhesive made of 180 grams of "Lankro G 600", 120 grams of PAB 1 "and 0.9 grams of tin octate is packed in a central area at the bottom of the molding box and the plate is opened this introduced mixture supported without being attached to the sheet steel floor.

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Claims (3)

1957Q12 - ». 7 - Patent claims: A method for producing a casting mold from a preformed plate, characterized in that the plate is inserted into a casting box in such a way that its side to be reproduced on the casting is directed upwards and the rear side faces the bottom of the box, the space between the bottom the plate and the bottom of the box and around the plate is filled with plastic foam, which is at least partially introduced into the box in the form of a closed-cell or substantially closed-cell foam-forming approach and fills at least part of the space and through openings in the Plate can escape, which is cut through one or more openings in the plate and around this excess foam to adapt to its surface, the casting compound is introduced into the casting box and the casting is removed from the box after it has solidified or set. 2. The method according to claim I _3, characterized in that the plate is additionally attached after insertion into the box. 3. The method according to claim 1, characterized in that the to be provided between the plate and the bottom of the box The space is filled with a mixture of discrete particles of expanded or foamed plastic, the 109871/1674 jm ~ m ^ cm bad original moistened with a resinous adhesive and in the Space is stuffed in - before the foam-forming Approach into the (openings on the sides of the hat and into any openings in the plate, the foam of which denotes the fills the remaining space below and at the edges of the plate. 109871/16 7 U
JAHfiÖiBO ORiGlNAL INSPECTED