Damage reason of injection mould and classification of steel
Publisher: Administrator Date：2020-07-31
Plastic injection mold processing is very widely used today. Recently, the plastic industry has received some questions from colleagues and friends. The most reflected is that when the injection mold is processed, the mold damage is the most troublesome for the manufacturer. Share with you. What is the reason.
If the mold processed by the injection mold is the same for a long time, it is very easy to be damaged if the maintenance is not done properly. This is undoubtedly a big burden for the injection mold processing plant, because the cost of the injection mold processing is very high. expensive.
We believe that the reason for mold processing damage during injection mold processing is that when the injection mold is assembled, there is no external force applied to it, but once it is installed on the injection molding machine and the injection mold is processed, it will withstand various external forces. This will cause damage to the injection mold, so the injection mold must have sufficient strength to withstand various external forces.
Finally, the inside of the cavity is completely filled, and the injection strength must be large to allow it to flow. Although the pressure is usually maintained for less than 1 second, it still produces a certain amount of core and cavity for injection mold processing Shock.
The color of the injection molded product plays a vital role in the overall feeling of the product. Our friends who are engaged in injection molding know that the uneven color of the product during the injection molding process of the injection mold is a very headache for us. Here we talk about the cause of injection molding What is the reason for the uneven processing color.
1. The colorant spreads poorly, which often causes patterns to appear near the gate.
2. The thermal stability of plastics or colorants is poor. To stabilize the color of the parts, the production conditions must be strictly fixed, especially the material temperature, material quantity and production cycle.
3. For crystalline plastics, try to make the cooling rate of each part of the parts consistent. For parts with large wall thickness differences, colorants can be used to mask the color difference. For parts with uniform wall thickness, the material temperature and mold temperature should be fixed. .
4. The shape of the part, the form of the gate, and the position of the part have an impact on the filling of the plastic, causing some parts of the part to produce chromatic aberration, which must be modified if necessary.
Different types of injection molds have different requirements for design drawings and mold steel. Different mold steels make the performance of injection molds different. The following are the classifications and characteristics of the major steels used to make injection molds.
1.101 type steel molds, using precision injection molds that are produced ≥ 1 million times and have a long service life. The characteristics are: (1) the hardness of the mold base material is at least 280BHN, (2) the hardness of the inner mold inserts in the cavity must be hardened Up to 48～50HRC, there are also sliders, wedge blocks, pressure blocks, etc., which need to be injection molded for hardening. (3) The slider must have wear-resistant blocks, the push rod plate must have guide posts, and (4) Cooling channel recommendations 420 stainless steel is used as inserts to avoid rust and cleaning.
2.102 steel molds, with a service life of 500,000 to 1 million molds, mass production of injection molds, the characteristics are: (1) the hardness of the mold base material is at least 280BHN, (2) the hardness of the inner mold inserts in the cavity must be hardened Up to 48～52HRC, other parts shall be processed accordingly. (3) Choose whether to install according to the production quantity requirements: slider wear block, push rod plate guide post, electroplating cooling water hole and electroplating cavity.
3.103 molds, using production times of 100,000 to 500,000 molds, medium batch injection molds, featuring: (1) the minimum hardness of the mold base material is 165BHN, (2) the inner membrane insert steel is P20 or higher hardness steel.
4.104 molds, production service life is 500 to 100,000 molds, small batch production of injection molds, characteristics are: (1) mold base material P20, mild steel or aluminum can also be used, (3) aluminum and mild steel for inner membrane inserts Or other metals.
5.105 type molds, the production life is less than 500 times, can be used for single-piece production and experimental molds. The characteristics are: aluminum alloy, epoxy resin or other materials are used, but a certain strength is required.