- May 13, 2020
- Posted by: Plastic Injection Molding
- Category: plastic injection molding
Plastic injection molding, like all plastic utensil creation procedures, has a procedure that consists of a cycle that must be completed from start to finish in order to function. In the event that this cycle fails, or is not completed, it is common to expect errors in the pieces which would lower the quality of what we are creating. Therefore, we must know the complete cycle and be able to be aware of what is happening
The injection molding process is really simple and in some cases fast, everything can really vary from the speed with which the molten plastic is injected or the time it takes to finish hardening the object, what is certain is that they must be complete 6 mandatory stages throughout the cycle so that the results are correct.
- The first stage is the closing of the mold, at which time the two parts of the mold are hermetically sealed and the molten plastic is prepared in the machinery.
- Next is the injection of the plastic, where the valve is opened and with the help of a spindle the molten material is pushed until it covers the entire cavity of the mold.
- Holding, the pressure inside the mold is maintained to ensure that the piece achieves the proper dimensions, remember that when cooling objects tend to contract.
- Material load, in this stage the pressure is totally eliminated and the piston is withdrawn when closing the valve.
- Remaining cooling, at this stage the part will have already finished cooling, being the longest process of the entire cycle.
- Opening / Launching, the press is in charge of opening the molds and by means of pistons they eject the part out of the cavities, at which time the molds can be closed again and restart the process.
Recall that the cooling process begins in the holding stage and progresses progressively until ending in the cooling remainder stage.
Taking into account that the cycle time can vary depending on many factors, among the most significant can be the type of plastic, part dimensions or speed to inject the molten material.
Similarly, there are times between cycles that can be calculated to know the number of plastic pieces that can come out in a given time, taking into account the materials of the mold and the cooling system.
We must make tests to take the times and finally know the total time required for one or more pieces, the cooling time must be measured, which will be the longest, since it depends on the plastic solidifying and not showing deformations.
The injection time, being all that it takes for the machinery to enter with the spindle all the molten material into the mold cavity and finally being the vacuum time, which is what it takes while the molds separate and the pieces come out of the.
The total cycle time will be the sum of all the times mentioned above, with this data you can calculate the number of pieces that can be removed in a given time.