Material introduction of plasticized screw 1. ACM2 (We […]
Material introduction of plasticized screw
1. ACM2 (West German material, commonly known as black and white cross): ACM2 is an aluminum-molybdenum-nickel-molybdenum alloy steel, which can be quenched and tempered up to HB280 ~ 320, and can be nitrided for 72hr and can reach HV> 800 hardness. However, the effect of hard chromium plating is not good, and it is used for the plasticized screw and melter barrel of the general tube group.
2. MAC24 (Mitsubishi material, quenched and tempered nitrided steel): Does not contain aluminum, so there is less white layer after nitriding, nitriding hardness is about HV800 ~ HV950, and the effect of acid-resistant hard chromium plating is good.
3. Double alloy: Its manufacturing method is divided into PTA tooth top spray welding and HP / HVOF spraying, which need to be selected according to different plastic characteristics. Its surface hardening hardness reaches HRC74, super hard alloy with good wear resistance, its film density is as high as 98 ~ 99.8%, and its surface adhesion strength is above 10,000psi. It can be known that the plasticized screw is the heart component of the injection molding machine, which is responsible for the transportation, melting, mixing, and metering of plastic raw materials. Therefore, the plasticized screw is closely related to the quality of the molded product.
The research of plasticizing screw is nothing more than:
First, improve the effect of shear mixing (dispersive mixing).
Second, improved uniform mixing (dispersive mixing).
3. Improve plasticating capacity.
Fourth, improve the temperature uniformity of the melt. When the tooth depth of the feed section is deeper, the conveying amount is larger, but the torque required by the screw is larger; the tooth depth of the feed section is too shallow, the conveying amount is insufficient, and the compression ratio is insufficient. When the tooth depth of the measuring section is too deep, the compression ratio is insufficient, and the required feeding force is large; when it is too shallow, it is easy to overfire and burn. Generally the tooth depth is about 0.03 ~ 0.07 times the screw diameter. Therefore, the plasticizing screw has the functions of conveying, melting, mixing, compression and metering, and plays a very important role in plasticizing quality.