Types of Mold Plastic Injection
Process injection molding is process to manufacture plastic product using injection molding machine. Shape of product that will be made was according to the mold. You should design the mold accurately to get the product is same with your desire on shape and dimension. But do you know what kinds types of mold process injection molding?
Generally there are two kind types of mold process injection molding. Those types of mold are divides according to gate system of flow material inside to the cavity and removal product out side the mold.
Types of mold according to gate system
- Runner Gate. This types of mold was has the way to flow plastic material from barrel direct to the cavity through a sprue bush.
- Three plate tools. There are 3 plates on the front device of mold: clamping plate (to tie the mold on the machines), runner plate and cavity plate. Usually it is use for a mold that has more than one cavity. Runner is to be between on the runner plate and cavity plate. When removal the product, those plate was follow to open and we can to put out the runner.
- Rod runner . This types of mold has the way to flow plastic material on the plate cavity front or/and rear. Or with other word gate is on the parting line of product.
- Hot Runner. Mean types of mold is a mold that has heater on its runner, usually used for processing plastic material that have high viscosity and fast crystallize.
Types of mold according to removal product system
- Ejector. Mechanism this types of mold is use ejector pin that placed on the ejector plate. When this plate is push, the ejector pin will push out the product out side from cavity.
- Stripper. Mechanism of its types of mold is plate cavity can to push forward to remove the product whereas the core is inaction.
- Slide Plate. There are cavity/plate cavity slide in order to removal the product.
- Core ejector. This types of mold is utilize mechanism core was pushed to removal product whereas plate cavity is inaction. Usually all of it removal system was pushed by hydraulic, pneumatic or mechanic system.
There are two types of mold according to gate system and product removal system. Basic principle of mold is gets the best product with simplest process and lowest runner.
What Does a Cavity Look Like
Mold of injecting molding is consists of four main component. There are mold base, runner, cavity and ejector segment. Mold base is the body of mold. Runner is use to flow plastic material from barrel of injection molding machine inside to cavity mold. The function of ejector segment is to push product outside the cavity. Then what does a cavity look like?
Cavity is heart of the mold injection molding. Cavity was shaped according to shape of product will be made. Cavity was divide at two apart that each installed on front and rear of mold base. So there is the parting line found in the each product of injection molding.
There are two kind of cavity, first the cavity is integrates with the mold base. This type is simple in process machining but if it was damaged need to repair all of cavity and mold base. The second type is cavity is separate from the mold base. It is installed in mold base and mold base was become a seat of cavity. It is more time to process machining when make a mold but more simple to repair if cavity was broken and it is more possibility to make the stockpile of the cavity.
The shrinkage of plastic material must be calculated when design cavity. It is important to get dimension of product according to our desire. The cavity is bigger than real product exactly. You must to know degree of shrinkage on the plastic material will be use. The chart of shrinkage degree plastic material can you see in the standard catalogue of plastic material and in the material data sheet of label plastic material that your choice.
However, usually the calculated of shrinkage was not suitable with our desire at the first trial injection because parameter setting of machine and other influence factor. It was really need trial injection process and little repair cavity until get the best result according our desire. Then mold is ready to use mass production.
Something that you must to no miss when design cavity is calculates in other that the product will brought to the rear of mold cavity where the ejector segment is there. It is important to make easier remove product outside of cavity. Sometime puller is needs to make it happens.
That is the short article to explain the question “what does a cavity look like?” Mold, especially cavity is your precious asset, so you must take care of them maximal during process and after process production.