A complete injection molding cycle consists of the following processes:

Mold Closure – Injection – Pressure Holding – Material Storage – Injection Retraction – Cooling – Mold Opening – Ejection.

This is the most basic process. If necessary, we will add neutron core extraction, gibbing, blowing and other actions.

Mold Closing: The process of mold opening to locking. It is divided into several stages: fast mold closing, medium speed mold closing, low pressure protection, high pressure mold locking. This process is to close the mold smoothly and smoothly, protect the mold and lock the mold.

Injection: The screw advances and squeezes the molten material into the mold. The injection stage is divided into injection and holding pressure. Injection is to let the molten material in front of the screw head advance according to the set parameters. The melt gradually fills the mold under the push of the screw. Since the high temperature melt has to shrink during the curing process, there is still melt to be filled again. This make-up shrinkage stage is the holding pressure.

The storage material, also called melt, is stored. After the melt is consumed in the injection stage, it needs to be replenished for the next cycle, and storage is the process of replenishing the melt and measuring it. At the end of the holding pressure, the screw rotates and transports the material forward from the back, during which time the material melts and accumulates in the head of the screw due to shear and the presence of heat. The screw does not actively move backwards in the process of storing material, but as the material gradually increases in front of the screw and builds up pressure, the injection nozzle is again blocked by the material in the mold, so the screw is pushed backwards by the molten material and stops at the metering point. Screw backward process, the resistance, called back pressure, is also the screw in front of the molten material to build up the pressure. The resistance of the screw receding can be adjusted by the back pressure valve to make the front melt more dense.

When the shot retreats, after the storage is finished, the screw actively retreats a small distance to reduce the melt pressure at the head of the screw. This prevents overflow caused by excessive pressure.

Cooling, the injection molding machine is only responsible for timing this process, the cooling water on the mold is responsible for the exchange of heat. The cooling timing starts from the end of the holding pressure, so the action of material storage is completed within the time of cooling. Another point is that even if the cooling time is set to 0, the next action will still be performed after the storage action is completed. The cooling time is a relatively large part of the whole cycle.

Mold opening, after the cooling is completed, the mold is opened. Action process: high pressure mold opening, fast mold opening, medium speed mold opening, slow after mold opening. The whole action is smooth and fluent, no jitter and accurate position when it is close to the end of mold opening.

Ejecting, the product after mold opening stays on the mold moving die and needs a lot of force to take off. There is an ejector mechanism on the mold to eject the products. The ejector bar of the injection molding machine is against the pushing plate of the mold, and the pushing plate together with the ejector pin moves forward to hold the products out.