Views: 1 Author: Site Editor Publish Time: 2021-09-18 Origin: Site
When the molten plastic parison falls on the open mold, the electrostatic charge will cause the following problems:
1. When there is more than one parison on each mold, the static charge always has the same polarity. This way the parisons will repel each other. In this case, it is usually impossible to transfer the object to the tool, and the pressure line on the molded product will also cause quality problems.
2. For a single parison, when the single parison is adsorbed by the metal parts of many machines, similar problems will also occur.
Reasons for blowing static electricity:
Any substance is composed of atoms, and the basic structure of atoms is protons, neutrons and electrons. Scientists define protons as positive, neutrons are uncharged, and electrons are negatively charged. Under normal conditions, the number of protons and electrons of an atom are the same, and the positive and negative charges are balanced, so it appears uncharged to the outside. However, due to external effects such as friction or in the form of various energies such as kinetic energy, potential energy, thermal energy, chemical energy, etc., the positive and negative charges of the atoms will be imbalanced. The friction in daily life is essentially a process of constant contact and separation. In some cases, static electricity can be generated without friction, such as induced electrostatic electrification, pyroelectric and piezoelectric electrification, Helmholtz layer, jet electrification, etc. Any two objects of different materials can generate static electricity as long as they come into contact and separate. Of course, flowing air can generate static electricity.
Plastic materials are produced and processed into plastic semi-finished products or finished products. Since most plastic materials are poor conductors and have good insulation properties, they are very easy to handle, contact, separate, friction, collision, and interfere with electromagnetic induction during the production process. If static electricity is generated in occasions, and staying on the surface of the article for a long time, it will cause static electricity hazard after it has accumulated to a certain static voltage value. For static electricity problems in the plastics industry, there are usually the following methods.
Blow molding electrostatic solution:
1. Chemical method: add antistatic agent that has moisture absorption effect and harmless to plastic to reduce the surface resistance of plastic material. The types of antistatic agents selected according to different types of plastics are used; both ionic and non-ionic are hygroscopic antistatic agents. After adding these additives, these materials can absorb moisture in the air and reduce surface resistance. Achieve anti-static performance.
2. Physical methods: Generally, the most commonly used anti-static measures are grounding and maintaining the temperature and humidity of the working environment. It is also possible to install some products specifically designed to eliminate static electricity on jobs that are extremely prone to static electricity to eliminate static electricity.
3. Installing static elimination equipment on high-speed blister molding machines, slitting machines, blow molding machines and other plastic machinery and equipment can effectively eliminate high-voltage static electricity generated when plastic sheets are pulled at high speeds, and prevent the sheets from attracting dust in the air due to static electricity Or the sheets adhere to each other due to static electricity, which effectively improves the product grade and quality of the plastic sheets after production and processing.
4. Install an electrostatic ion bar at the entrance of the plastic raw material of the plastic injection molding machine to eliminate the high-voltage static electricity generated by the raw material in the flow, so as to prevent the raw material from forming agglomerates and piles at the entrance directly affecting production due to static electricity.