SU608654A1 - Method of making the shaping component of a mould - Google Patents

Description

one

The invention relates to the field of processing of polymeric materials in an article by extrusion in molds and, in particular, to methods for producing molding parts of the mold.

The known forming part of the mold and the method of its manufacture, including the manufacture by electroforming of a metal shell, its bonding with a metal holder, filling the cavity between the shell and the holder with good compressive strength, such as cement, gypsum, river sand, etc., and base fixing 1.

The known shaping part is used in the Mold as a matrix.

During the operation of the mold, the processed thermoplastic sheet material is fed and molded therein in a heated elastic state, thereby acquiring a configuration that corresponds to the configuration of the forming surface of the mold matrix.

However, due to the fact that the fabrication of the metal shell is carried out by the electroforming method: it is not possible to provide a rigid bonding of the shell with the holder in the known forming part of the mold according to the model outside the cage. As a result, the forming surface of the mold is distorted during its operation, which is a significant drawback of the known forming part of the mold, predetermined by the lack of a method of its manufacture.

The closest to the invention is the method of manufacturing a mold part of the mold, in which the holder produces a metal shell by spraying a model, fills the cavity between the shell and the nonmetallic holder and fixes the base 2. The mold produced in this way is used as punch or die.

It is known that the work of the forming part in the mold is most often associated with heating and high loads, as a result of which thermal and force deformations are possible, distorting the configuration of the form: reflecting cavity of the mold. In the mold part of the mold,

manufactured by a known method, the materials of the metal shell and the non-metallic filler have different coefficients of force deformation and thermal expansion. As a result, during the work of this part, deflection (or buckling) of the sprayed casing with a shaping surface is possible, at which the configuration of the compressible product becomes distorted.

The aim of the invention is to eliminate the distortion of the shell from the temperature effect during the operation of the mold.

This is achieved by the fact that, before fixing the base, the holder with the shell, the filler, the base and the model is heated to the operating temperature, then the aggregate is compressed with a force equal to the pressing force, and fixed.

FIG. 1 shows a section through a mold part of a mold during its manufacture; in fig. 2 is a section through a mold during manufacture of the product.

The manufacture of the molding part of the mold is carried out as follows.

A metal sheath 3 is deposited onto the model 2 enclosed in the metal case 1 and the inner walls of the case 1 in the zone of model 2 with its strong adhesion to the wall of the case 1.

The bottom of the resulting cup, the bottom of which is the shell 3, and the wall of the holder 1, is filled with non-metallic material 4, for example glass fiber with a binder capable of providing the material with the necessary strength and heat resistance.

The filled cavity is closed with a base 5, which is adapted to move inside the sleeve 1.

The filler 4 is compacted by acting on the base 5 and held in the pressed state until it solidifies.

After curing, the filler 4 together with the yoke 1, the shell 3, the model 2 and the base 5 is heated to a temperature at which the mold is intended to be used.

Next, the base 5 is affected by a force equal to the magnitude of the working force during the subsequent extrusion of the product in the mold. The filler 4 is elastically deformed. In this state, the filler 4 is used to secure the base 5 to the holder 1 of the part with, for example screws 6.

As a result, after removal from the model 2, a mold-forming part is obtained in which the shearing forces from the core 4 act on the walls of the shell 3.

During the operation of the mold (Fig. 2), the shearing forces acting on the walls of the shell 3 forming it, also caused by the compression of the material of the pressed product 7 by means of the punch 8.

As a consequence, the shell 3 on both sides are the same in magnitude, but opposing forces.

As a result, the sheath 3 in the process of pressing the product 7 is in a neutral force and is not subjected to a distorting configuration of the deflection from workloads and thermal expansion of the non-metallic aggregate 4.

An important point in the implementation of the proposed method is the informed choice of the material of the filler 4 and the binder.

For the operation of a mold part with a filler made of fiberglass at a temperature of, for example, 150 ° C and a specific pressing pressure of 300 kgf / cm, the following composition can be used as a binder, weight. h .: Epoxy resin ED5 or ED6 by

GOST 10587-76100

Maleic anhydride according to GOST 5854-71 (hardener) 30-40.

In order to impart elasticity to the specified composition, liquid ticol of the brands NVT and NVB according to MRTU 6.04 No. 174-64 in the amount of 15-25 wt. h

For the working conditions of the mold part at a temperature above 150 ° C, it is advisable to use a binder based on silicone resins, such as silicone resin 9, on the basis of which SC9F glass fiber laminate or glue VKT-2 and VKT-3 are obtained.

As a result of using the method of manufacturing the mold forming part of the proposed method, the shaping surface of the mold is distorted during the extrusion process, and, consequently, the accuracy of the shape and quality of the resulting product will increase.

In addition, it is possible to reduce the thickness of the sprayed shell with the shaping surface, which reduces the cost of manufacturing the mold.

Claims (2)

1. USSR author's certificate number 110865, cl. In 29C 1/00, 1956. 2. The patent of the Federal Republic of Germany No. 901240, cl. 39a 14, 1954.