First: The working speed of the screw of the injection molding machine is unstable, which is affected by the following factors:
1、The driving V-belt is severely worn and slips during work.
2、The center distance of the V-belt drive pulley is too small, so that the belt drive cannot correctly friction drive with the trapezoidal slope of the pulley.
3、The temperature of the heating material in the barrel is low, and the plasticization of the raw materials is not uniform, which causes the increase of the working load torque of the screw of the injection molding machine, and the screw speed of the injection molding machine is unstable.
4、The thrust bearing of the screw of the injection molding machine is damaged.
Second: The influence of the unstable working speed of the screw of the injection molding machine on the quality of plastic products:
1、The geometric shape and size error of the product is large;
2、The product will often show horiz
3、The surface of the product is rough, brittle, or partially hard.
Third: The rotation speed of the injection screw should be selected according to the injection conditions.
1、Use the rated screw speed of the injection molding machine. When PS is injected, the plasticizing capacity and screw speed of the material to be processed are calibrated with 50%-60% of the rated plasticizing amount.
2、Determine the screw speed according to the maximum linear speed allowed by the polymer.
螺杆最高转速 n=V/πD式中 V----聚合物允许的最大线速度。一般聚合物V=80cmm/S,热敏性聚合物V=1.8cm/s D----螺杆直径（cm）
Maximum screw speed n=V/πD where V----maximum linear speed allowed by polymer. General polymer V=80cmm/S, heat sensitive polymer V=1.8cm/s D----screw diameter (cm)
3、Determine according to the allowable shear rate r of the polymer, which can be determined after replacing V in the above formula with r.
When adjusting the screw speed, start from a lower speed, adjust to a higher speed gradually, and then determine the screw speed.
The above content is organized and provided by Taizhou Jiaojiang Jingyi Machinery Factory. It is a comprehensive enterprise specializing in the production and sale of various belt pulleys, hand wheels, pulleys, couplings and other transmission machinery accessories. It covers an area of more than 10,000 square meters, has 30 years of production history, large-scale production, and rich experience in technical staff. Designers can design, process and produce various types and specifications of products and castings from 40mm to 1500mm according to the drawings provided by customers or related data of conventional models. The raw materials used in our factory are all standard qualified alloys. The products have excellent craftsmanship, long service life, high movement precision, convenient disassembly and assembly, and can effectively improve the quality of the whole machine. Many domestic and foreign manufacturers and merchants have sent large quantities to our factory. order.