CS231440B1 - Filling material of pressing tools - Google Patents

Abstract

Cement or concrete-based filling material is intended for pressing tools, especially electroplated shells. The filling material contains 10 to 30% by weight of cement or concrete and 70 to 90% by weight of metal bodies, for example powders, sawdust, chips, granules, rivets, either separately or in combination, with a water content of no more than 0.8% by weight of cement.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction material for the construction of press tools consisting of an active layer consisting of a metal alloy generally excluded galvanoplastically and resistant to mechanical and thermal stress, and of a filler material. clamping parts of the forming machine.

The electroformed face of the tool, which is relatively thin with respect to the dimensions of the tool, cannot withstand the pressures generated by the molding process.

The heat generated either by the pressing process or by the heated molding material is heated very quickly above the allowable temperature and thus the mechanical properties of the active layer are reduced. ,

After a longer time it deforms. Therefore, the facing galvanoplastically deposited active layer is supported by a filler material which, in addition to the transfer of mechanical and thermal stresses, fills the space between the active surface and the clamping surface of the press, thereby forming a substantial part of the tool.

At present, low-melting alloys based mainly on zinc-aluminum, lithium or cast resins with different fillers or different types of concrete are used for fillers. Metal alloys need to be cast into the shell, which in practice significantly limits their selection.

The melting point of said alloys must be less than the permissible maximum operating temperature of the electroplated metal. This temperature is around 300 ° C. When cast metals are used as fillers, there is a real risk of deformation of the thin shell due to dilatations during solidification into the poured metal shell.

Resin and concrete based fillers do not create such high thermal stresses on the galvanoplastic shell when applied; their disadvantage is low thermal conductivity, which is unfavorable in operation, when the tool is thermally stressed and it is desirable that the filler material dissipates heat well.

Most of these disadvantages are overcome by the filler material of the molding tools, especially the galvanoplastic shells according to the invention, made on the basis of cement or concrete. The invention is based on the fact that the filling composite contains 0 to 30 wt. % cement or concrete and 70 to 90 wt. metal bodies such as sawdust, powders, chips, sticks, granules, rivets, small metal parts, alone or in combination.

The water content of the cement is 0.8.

The fillers according to the invention have a higher thermal conductivity than plain concrete. The solidification, which takes place at a temperature of 20 to 50 [deg.] C., does not cause as large dilatations and therefore no deformations of the galvanic shell as induced by the solidifying metal alloys.

Since less valuable solid alloys can be used as filler metal, the use of a filler material for die tools is more convenient and substantially more economical.

Example 1

The filler mass of the galvanoplastically produced stamping tool consisted of a mixture of 20 wt. cement with 80 wt. 50 to 100 µm iron grits and 0.8 weight of water in cement.

After mixing the individual components, the filler was filled with a galvanoplastic shell that formed the face of the tool. The electroformed shell was placed in a mold that restricted the lateral surfaces of the tool. To achieve a better connection of the galvanoplastic shell with the filler, anchor wires of 0 - 1-2 mm were welded to the zero side of the shell. This filler material exhibited more than twice the thermal conductivity than plain concrete.

Example 2

The filler mass consisted of a mixture of 40 wt. % of cement mixed with fine quartz sand, 40 wt. fillers in the form of chopped copper wire of 0 mm and length of 25 mm and water of a weight corresponding to 0,8 weight of cement.

After mixing with each other, this mass was filled with a galvanoplastic shell placed in a working form limiting the lateral sides of the future tool. Anchoring wires of 0 mm were welded to the reverse side of the galvanoplastic shell to ensure the bonding of the filler to the shell.

This filler material exhibited a significantly higher thermal conductivity than plain concrete.

The fillers may also advantageously be used in the filler material for copper, aluminum or iron sawdust, chips, powders, rivets or chopped wire with a diameter of 1 to 2 mm and a length of 25 to 50 mm. molds, for example with a laminate functional layer.

Claims (1)

Molding tool filler, in particular of galvanoplastic shells, made on the basis of cement or concrete, characterized in that it contains from 10 to 30 wt. % cement or concrete and 70 to 90 wt. metal bodies such as sawdust, shavings, granules, rivets, and the like, alone or in combination with each other, with a water content of not more than 0.8 weight of cement.