What are the skills and points to be paid attention to in injection molds?

The importance of regular polishing of injection molds to ensure consistent
molding quality, improve the lifespan of the machine and extend the service life
of the cutting tool.

Specific characteristics for polishing injection molds:

There is no fixed number of times to re-grind an injection mold based on
sharpness. It depends on the sharpness of the cutting edge of the cutting tool.
Three factors are taken into consideration:

(1) Check the radius of the cutting edge corners. If the radius exceeds
R0.1mm (maximum R value cannot exceed 0.25mm), it needs to be polished.

(2) Check for rough molding. Are there many burrs?

(3) Check for noise during molding. If the same cutting tool produces a loud
sound during molding, the cutting edge is dull, it needs to be sharpened.

(4) Check the cutting edge of the cutting tool. There may be burrs on the
cutting edge.

Sharpening methods:

There are various ways to quickly grind injection molds, including using a
special grinder or a flat grinding machine. The frequency of the rotary table
and lower mold can be 4:1. Be sure to adjust the angle of the rotary table after
grinding.

(1) The incorrect sharpening method of injection molds has a serious impact
on the sharpness of the cutting tool, leading to frequent damage to the cutting
edge of the tool and reducing the sharpening efficiency.

(2) Correct sharpening methods for injection molds have the following
advantages: regular sharpening of injection molds can ensure that the mold
surface quality is consistent and the precision of the mold is stable. The
cutting edge of the cutting tool is damaged less frequently, and the lifespan is
longer.

Sharpening rules for injection molds:

When considering the following factors in sharpening injection molds:

(1) For R0.1-0.25mm cutting edge corners with a sharpness angle, the cutting
edge should be sharpened.

(2) The grinding wheel surface should be cleaned properly.

(3) Recommended use of soft abrasive wheels such as WA46KV.

(4) Each grinding pass (tool size) should not exceed 0.013mm. Excessive
grinding will cause the injection mold surface to become too hot, resulting in
thermal expansion, making the injection mold surface even softer. This will
greatly reduce the lifespan of the injection mold and machine.

(5) Grinding should be performed while adding sufficient cooling water.

(6) During grinding, the upper and lower mold should be fixed securely, and
special clamping tools should be used.

(7) The sharpening frequency of the cutting tool is fixed. Once the value is
reached, the cutting edge will be broken. If this continues, the cutting edge of
the injection mold and machine will be seriously damaged.

(8) After grinding, the sharpening edge should be processed with a grinding
stone to remove the sharp edge at the edge.

(9) After sharpening, wash, and degas. Please refer to this article.

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