Injection mold surface treatment

What methods of injection mold parts surface treatment? In the working process of the injection mold parts on the surface of the working condition is bad, so it's easy to damage, therefore, need for some parts surface to surface treatment, for local enhancement.

The effect of surface treatment (1) parts

In mould processing, surface treatment can make the parts for the following properties: increasing surface hardness, increase the compressive strength, abrasion resistance, improve the corrosion resistance and improve the sliding, etc.

(2) parts surface treatment methods

Surface treatment method are many, but for the mold parts, main methods of surface treatment are the following.

1) carburizing. Carburizing is to the steel surface infiltration carbon atoms. It is to put the parts into can release the active carbon atom medium, heat insulation, make activated carbon atoms permeability and the surface of the steel. Its purpose is to improve the surface of the carbon content, the subsequent heat treatment, the surface hardness increased, while the core remains resilient. Therefore, carburizing steel must be 0.15% ~ 0.25% (mass fraction), the carbon content of mild steel. Methods include solid carburizing, carburizing liquid carburizing and gas carburizing, is widely used gas carburizing.

2) nitriding (also called nitride). Nitriding is to the steel surface infiltration nitrogen atoms. Its purpose is to improve the parts table surface hardness, wear resistance, corrosion resistance and fatigue strength. At present, the most widely used method of nitriding is gas nitriding. It is to put the parts into the airtight furnace, the ventilation with NH3, heating to 500 ~ 600 ℃, the ammonia decomposition of reactive nitrogen atoms, the nitrogen atom is easy to be absorbed by the workpiece surface and spreading inside, forming a nitride layer, nitriding layer is 0.1 ~ 0.6 mm. Nitriding layer has high hardness and excellent dimensional stability, and can noticeably improve wear resistance and fatigue strength, corrosion resistance has greatly improved. In the mold processing, almost all steel nitriding processing. But it's a longer production cycle, high cost.

3) hard chromium plating. Hard chrome plating is will adopt the method of plating chromium plating on surface of parts, thereby gaining the surface of the hard and wear resistant, it to contain the abrasive plastic molding parts, hard chromium plating layer is very effective. In addition, the hard chromium layer can not only reduce the wear and tear, and can significantly improve the corrosion resistance of parts. Can also be used when repair the wear surface hard chromium plating method processing.

4) hard nickel plating. Hard nickel plating is to use chemical method will nickel plating layer on surface of parts. In the process, deposition of nickel layer does not use imposed by the electron flow, so you don't happen like electroplating on the edge, especially along the edge to form different thickness of electroplating film formation (edge) of the phenomenon. This method of nickel plating in the hole, opening and the place such as contour surface defects will not appear. The nickel plating layer often about 40 microns thick, it can form has good corrosion and wear resistance of the surface.

5) coated hard layer. In order to make the part surface with a high wear resistance and corrosion resistance, there is a new technology is in the surface coated with titanium nitride and similar material for grass-roots approach, it is easy to operate, and the effect is very good.

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