Plastic Hollow blow molding machines keep the head of the parison clean and are an important prerequisite for extrusion blow molding of high performance products.
Some polymers degrade during processing, especially if the melt is retained in the storage tank for a period of time at high processing temperatures or intermittent blow molding. In addition, the blow molding grade contains a variety of additives that produce by-products during the melting process. These degradants or by-products will accumulate in the flow path of the head, causing streaks on the surface of the parison, which will affect the appearance of the product. In the production process, the cleaning methods of the machine head are as follows.
1 Manual cleaning. Before disassembling the machine head, the machine head should be heated above the melting point of the plastic. It should not be heated by the flame of the burner to avoid local overheating of the machine head, affecting the size of the die and the mandrel. After the material inside the standby head is melted, stop heating and remove quickly. Heater, remove the starter head, use copper or copper knives to remove the melt remaining in the flow path of the nose, and then clean it with brass wool.
If conditions permit, a high velocity gas stream can also be used to remove the melt from the handpiece and then cleaned with brass wool to remove the charred paste.
2 solvent cleaning method. The solvent is used to clean the head flow path to avoid side injuries. In general, cleaning the head with an alkaline or acidic chemical is not as efficient as cleaning with an organic solvent, and the former also erodes the surface of the runner more or less.
After solvent cleaning of the machine head, it is desirable to have a recovery unit to reduce cost and avoid contamination.
3 ultrasonic cleaning method. Ultrasonic cleaning, after washing, rinse with water to remove residual materials to avoid corrosion of the flow channel. The method has good cleaning effect, but the cost is high.