Basic injection molding process
When analyzing part design, mold making, and efficient production of molded plastic products, the stages of the injection molding process should be carefully considered. There are not many factors and configurations involved here, but the basic process is the same. Let's start with the basics.
Step 1: The mold is closed
When the mold is closed, the injection molding cycle timer starts.
Note: In some cases, as with robots, the cycle runs "part by part", meaning that the cycle starts and ends when the robot receives a new part or a new part touches the conveyor belt.
Step 2: Injection
Inject the heated plastic into the mold. When the melt enters the mold, the exhaust air escapes through the vent hole in the injection pin and along the parting line. The design of runners, gates and exhaust ports is important to ensure that the mold is filled correctly.
Step 3: Cool
Once the mold is full, the part is cooled to the exact time it takes to harden the material. The cooling time depends on the type of resin used and the thickness of the part. Each mold is designed with an internal cooling or heating line in which water circulates through the mold to maintain a constant temperature.
Step 4: Plastilate the resin
As the part cools, the barrel screws retract and the new plastic resin is withdrawn from the feed hopper. Heating strips maintain the required barrel temperature for the type of resin used.
Step 5: Pop up
The mold opens and the ejector bar moves the ejector bar forward.
The part falls and is trapped in a silo located under the mold.
Step 6: Remove the runner and package
Although the cycle of the injection molding machine ends in step 5, the process continues. The machine operator or robot periodically separates the usable parts from the remaining runners. * The runner is the channel through which the plastic fills the mold cavity. In many cases, runners are ground and recycled to reduce costs and environmental impact. The available parts are then weighed, counted and packed for assembly or shipping.
Final notes
The basic injection molding process is here. We work with our customers every day to help them understand the basic process of producing quality products. Keeping you, your customers up to date and understanding the fundamentals of the injection molding process, will help you communicate with molders. It will also help you understand and solve any problems he may have while molding the product.
Injection molding has advantages over other processes because it produces products accurately and at high speeds. To date, no other process has been able to meet the quality and consistency of this process when molding plastics. If you have any questions, please feel free to contact us