Injection molding machine selection: 1. The screw type […]
Injection molding machine selection:
1. The screw type injection molding machine is selected, and the plunger injection molding machine cannot be used;
2, to do a good job of anti-corrosion of equipment;
3. All parts in contact with PVC plastic do not allow any adhesion or retention to the plasticized melt;
4. The temperature control system of the equipment should be accurate and responsive;
5, the screw length to diameter ratio can be smaller, the screw head is pointed; the compression ratio of the screw is 2 ~ 2.5, the length of the three sections of the screw can be set to 40%, 40% and 20% respectively;
6, the general purpose nozzle of the aperture is selected, and is equipped with a heating temperature control device;
7. Master the technology of cleaning the barrel;
8. Pay attention to the temperature rise procedure, and pay close attention to the temperature rise during the heating process of the cylinder.
9. Whether the material in the barrel is overheated can be judged by whether there is brown streaks on the surface of the main material. If the material of the main channel has brown streaks, it means that the plastic in the barrel is overheated, and measures should be taken immediately to clean the barrel and must not continue to operate;
10. When stopping, first discharge all the materials in the barrel, and clean the barrel with PS or PE and other plastics in time, or add special PVC parking material to stop the original RPVC of the barrel.
11. Immediately after shutdown, apply oil and rust on the cavity and runner surface of the mold.
In the process of injection molding, the quality of PVC pipe fittings often appears abnormal. At this time, it is necessary to analyze the cause and find a solution. Often, a wealth of practical experience helps to identify problems and get solutions in a timely manner.