Mold Tool and Treatment Method for Mold Tool Surface

a mold tool and treatment method technology, applied in the field of mold tool and treatment method for mold tool surface, can solve the problem of dimension error of several tens of m that is not allowable, and achieve the effect of reducing the release resistan

Inactive Publication Date: 2011-03-24
JAPAN AVIATION ELECTRONICS IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0014]The mold tool and the treatment method for a mold tool surface thereof according to the present invention can significantly reduce the release resistance without affecting the dimensional precision of a fine molded product.

Problems solved by technology

However, for a fine molded resin product, such as a housing of a narrow pitch connector having a pitch of 1 mm or less, even a dimension error of several tens of μm is not allowable.
The commonly used method of forming recesses and projections by polishing has a problem that the frictional force due to the anchoring effect or the digging effect increases, so that the net release resistance is not significantly reduced, although the method reduces the adhesive force due to the meniscus because even the smallest recesses formed thereby have a depth of about 100 nm because of the limitations of the polishing device, and sharp-edged scratches are formed.

Method used

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  • Mold Tool and Treatment Method for Mold Tool Surface
  • Mold Tool and Treatment Method for Mold Tool Surface
  • Mold Tool and Treatment Method for Mold Tool Surface

Examples

Experimental program
Comparison scheme
Effect test

experiment 1

[0036]The relationship between the geometry of a surface of an injection mold tool that comes into contact with resin and the releasability of resin was examined.

[0037]Using the tool steel SKD61 as the material of the mold tool and a liquid crystal polymer as the resin material, a thin rectangular parallelepiped resin part having a length of 35 mm, a width of 3 mm and a height of 0.2 mm was molded. Three types of mold tools (mold tools 1 to 3) having different surface geometries were prepared. The surface of the mold tools 1 to 3 was treated as described below.

[0038]Mold tool 1: Ground with #400 grindstone

[0039]Mold tool 2: Ground with #600 grindstone

[0040]Mold tool 3: Ground with #600 grindstone and irradiated with gas cluster ion beam

[0041]The irradiation with gas cluster ion beam was carried out under conditions that an Ar cluster ion beam was used, the acceleration energy was 20 keV, and the irradiation fluence was 5.0×1017 ions / cm2.

[0042]The set resin part was released from the...

experiment 2

[0045]The relationship between the surface geometry of injection mold tools of the same type as those in the experiment 1 (except that the material was SKD11) and the releasability of the resin contact surface thereof was examined for various gas cluster ion beam irradiation conditions.

[0046]The gas cluster ion beam irradiation conditions were that an Ar cluster ion beam was used, and the acceleration energy Va, the irradiation angle θ and the irradiation fluence N were changed as shown in the table 2 shown in FIG. 7. The table 3 shown in FIG. 8 shows results of measurement of the density, the height and the diameter of fine granular projection structures formed by irradiation on the resin contact surface of mold tools 4 to 7 shown in the table 2 and the average roughness Ra for an area 1 μm square of the mold tools 4 to 7. No fine granular projection structures were observed on the mold tool surface that was not irradiated. In addition, the rate of successful releasing was examined...

experiment 3

[0047]Mold tools of the same type as those in the experiment 1 were made of SKD11 (tool steel) or V20 (a carbide material made of tungsten carbide and cobalt (Co) as a binder), and the relationship between the irradiation fluence of a gas cluster ion beam and the changes of the surface geometry was examined.

[0048]The gas cluster ion beam irradiation conditions were that the mold tool surface was perpendicularly irradiated with an Ar cluster ion beam with an acceleration energy of 20 keV. FIG. 9 is a graph showing a relationship between the irradiation fluence and the average roughness Ra evaluated for an area 1 μm square. The small graphs in the graph are enlarged graphs showing Ra for the mold tools made of SKD11 and V20 over a narrower range of irradiation fluence. Fine granular projection structures similar to those shown in FIG. 5D were observed when the irradiation fluence was equal to or higher than 2×1016 ions / cm2 for the mold tool made of SKD11 and when the irradiation fluen...

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Abstract

The average roughness Ra of a mold tool surface that comes into contact with a material to be molded measured for a measurement area 10 μm square or smaller is equal to or lower than 5 nm, and fine granular projection structures having diameters ranging from 10 to 80 nm and heights ranging from 10 to 40 nm are formed on the mold tool surface with a density of 400/μm2 or higher. The frictional force due to the anchoring effect or the digging effect is reduced, and the adhesive force due to meniscus is also reduced. The release resistance is significantly reduced without affecting the dimensional precision of a fine molded product.

Description

TECHNICAL FIELD[0001]The present invention relates to a mold tool and a treatment method for a mold tool surface.BACKGROUND ART[0002]In a process of molding a resin (plastic) product, a glass product, a metal product or the like with a mold tool, the product may be hard to release from the mold tool because of friction between the product and the mold tool. As known, the release resistance relates to the surface roughness of the mold tool. In the following, this will be described, taking resin molding as an example.[0003]FIG. 1 is a graph showing relationships between the surface roughness and the mold tool releasing force (release resistance) shown in Non-Patent Literature 1. As shown, the release resistance decreases with the surface roughness (average roughness) Ra until the surface roughness Ra reaches about 0.2 μm. However, in the range of the surface roughness equal to or lower than about 0.2 μm, the release resistance rapidly increases as the surface roughness decreases.[0004...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B29C33/40
CPCB29C33/42
Inventor SATO, AKINOBUSUZUKI, AKIKOKAWANO, TAKESHI
Owner JAPAN AVIATION ELECTRONICS IND LTD
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