Method for surface-treating mold

Abstract

Provided is a method for surface-treating a mold with which a simple treatment makes it possible, at low cost and in short time, to obtain simultaneously an improvement in mold release performance andan improvement in the surface hardness of the mold. In the present invention, a pre-treatment step is performed, in which the surface of a mold is adjusted, by, for example: dry-spraying a carbide powder having a grain size of #220 (JIS R6001-1987) or lower and a polygonal shape at a spray pressure of 0.2 MPa or higher onto the surface of a mold, to diffuse, on the surface of the mold, a carbon element that is in the carbide powder; and removing machining marks occurring on the surface of the mold. Thereafter, a post-treatment step is performed, in which a spherical powder having a hardness at least equivalent to the base material hardness of the mold and a grain size of #220 or lower is dry-sprayed at a spray pressure of 0.2 MPa or higher and made to impact the mold, to form countless minute indentations of arcuate shape on the surface of the mold.

Description

technical field [0001] The present invention relates to a surface treatment method of a mold, and more specifically, to a surface treatment method of a mold capable of providing a mold with good release properties and a long life. Background technique [0002] In the mold used for molding resin or metal, if there are cutting marks and / or grinding marks, knife marks and other processing marks or other unevenness formed on the molding surface that is in contact with the molding material, it will not only This unevenness is transferred to the surface of the molded product to deteriorate the appearance of the product, and the unevenness of the molded surface and the surface unevenness of the molded article formed by the transfer of the unevenness will also bite, so that the molded article is released from the mold. Sometimes accompanied by complicated operations or difficult to demould. [0003] Therefore, generally, the molding surface of the mold is processed into a predeterm...

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Problems solved by technology

[0007] However, in the above-mentioned mirror polishing using an elastic abrasive material, the processing time can be shortened compared with manual mirror polishing, but there is a disadvantage that it cannot handle mold processing with complex shapes.

[0008] In addition, because processing equipment for mirror surface processing by electron beam irradiation or 5-axis control multi-process automatic CNC machine tools is expensive, a large initial investment is required for introduction

At the same time, in mirror finishing by electron beams, the mirror surface is obtained by melting the surface of the mold and solidifying it flat by surface tension, so the surface part becomes crystalline and becomes intolerant to surface pressure, making The life of the mold is shortened

[0009] In addition, according to any of the above methods, the surface of the mold can be mirror-polished, but if the draft angle is reduced to close to zero in a mold for resin molding, etc., even if the surface of the mold is mirror-polished , sometimes the molded product will stick to the surface of the mold and it is difficult to release from the molded mold

[0010] In addition, the surface of the mold is worn due to frictional contact with the surface of the molded product during demolding, etc., especially in the case of resins in which glass, ceramics, metal powder, etc. are added as fillers to meet heat resistance and / or high strength requirements. In the case of molding of molding materials, the wear life of the mold is significantly reduced

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