Causes of screw failure of blow molding machine

The screw of the automatic blow molding machine is one of the important parts of the blow molding machine.

 In the daily production process, it is necessary to maintain the blow molding machine and the various parts of the blow molding machine. When the hollow blow molding machine screw fails, it is very important to find the cause. Let’s look at the key directly. The following is the reason for the hollow blow molding machine screw failure and damage organized by Qingdao Yankang Plastic Machinery.

First of all, what is the purpose of the blow molding machine screw?

 Simply put, the role of the screw is to melt all the raw materials into a liquid state, form a parison through extrusion, and perform inflation and molding. In the whole process, the work of the screw is to transport the raw materials and complete the plasticization.

After roughly understanding the work of the screw, let’s take a look at the cause of the frequent problems with the screw failure of the hollow blow molding machine?

After the above-mentioned plastic enters the screw, the screw is in the barrel, and friction between the plastic and the screw is carried out. With the friction process, the diameter of the screw becomes smaller and thinner, and there is a distance and gap with the barrel. As the screw gradually rubs, the screw becomes thinner and the gap between the screw and the barrel gradually increases. The resistance of the head of the barrel and the splitter plate remains unchanged, so that the material gradually enters the gap and stays for a long time, resulting in material decomposition. If the material is PE (polyethylene) and the screw temperature is high, the hydrogen chloride in the PE will be released, which will corrode the screw and barrel, which is also one of the reasons for the failure of the hollow blow molding machine screw.

2. Calcium carbonate is often used as a filler for plastics and glass fibers. Metal friction will cause greater damage than unplasticized plastic. why? In the high-speed operation of the screw, when the plastic is sheared, the sharp ends of some fibers will be exposed, which will cause the screw to be damaged during work and cause one of the failures of the hollow blow molding machine screw.
3. If the material is not completely plasticized in the barrel, or foreign matter is mixed in, the screw torque will suddenly increase, which will damage the screw. The material has not been plasticized or it may be the rotation speed of the screw. Or the screw back pressure and barrel temperature and other reasons. Therefore, in order to avoid the situation where the material is not completely plasticized, Beckwell shares several solutions.
1) First of all, the temperature must be controlled in accordance with the process regulations
2) To reduce the speed between the screw and the traction, lengthen the plasticization time and improve the plasticization effect
3) Screw cooling water can also be used to improve the plasticizing effect

What Beckwell shared with you is the analysis of the reasons for the failure of the hollow blow molding machine screw.

If you encounter the hollow blow molding machine screw failure problem during the production process, you can find the cause according to the specific situation of the problem.