What should we do before starting the hollow blow molding machine?

  Before starting the hollow blow-molding machine, you must strictly adhere to the following points:

  1. To cool the material card, turn on the cooling water so that all the cow screws bite into this phenomenon.

  2. Preheat the hydraulic oil. If the temperature of the hydraulic oil in the hollow blow-molding machine’s oil tank is too low, immediately turn on the heater, which is typically installed on the main unit.

  3. Press the start button and immediately stop. Check whether the pump is rotating in the correct direction. If you find that it’s not, immediately swap the power supply wires of the two connected motors.

  4. The machine should be started when the hydraulic system is completely depressurized. After starting, adjust the overflow system pressure of each pump to the specified value. In large injection molding machines, there are typically two separate pressure systems—one for the clamping unit and another for the injection unit; each system has its own pressure-relief chamber. After stopping the pumps, the relief valves must be opened. While the pumps are running, the relief valve switches must be closed.

  5. Adjust the direction of all travel routes to ensure smooth transitions for the moving template during long-distance journeys.

  6. Close the doors. According to the maintenance requirements when the operating-side doors are opened, all doors must be closed while the machine is running. For large-scale hollow blow-molding machines, the lifting and mold-closing actions will be halted: if one more door is opened, the oil pump will stop working.

  7. Turn on the heater and the temperature control system.

  8. When the mold is installed in the molding device, it is necessary to clean both the mold surface and the contact surface with the blow-molding machine’s template.

  9. On the hollow blow-molding machine, turn on the main switch L of the control cabinet, adjust the operation selector switch to either “Jog” or “Manual 1,” add the rust-preventive oil, and then pour in the liquid crude oil and allow it to settle smoothly.

  The screw feed is unstable. Typically, when the screw feed is too fast or too slow, the length of the extruded material may vary. The root cause of this issue usually lies in the servo valve and the electronic ruler of the hollow blow-molding machine. It could be that the servo valve and the electronic ruler are affected by electromagnetic interference, thereby disrupting the stable feeding process of the screw. Another reason related to the electronic ruler is that contamination on the electronic ruler can also impact the stability of the material feed.

  Before removing the screw, there was no twisting. Although this occurred before material discharge, it can be considered one of the abnormal discharge conditions in a hollow blow-molding machine screw. Generally, raw material processing is achieved through the coordinated control of temperature and screw rotation. If problems arise during the twisting process, these issues will naturally manifest themselves in both temperature and screw operation. If no material remains stuck, the cause could be that the temperature is too low and the material has not melted; alternatively, the discharge port temperature might be too high, causing the material to clog at the discharge point. As for the screw itself, the issue may stem from defects in its quality or performance.