How do I eject a secondary overmoulded injection mould?

In the plastic mould industry, the application of secondary overmoulding injection moulds is becoming more and more widespread. Such moulds not only improve the aesthetics and functionality of the products, but also enhance the durability of the products. However, for many mould makers, how to effectively eject the secondary overmould is a considerable challenge. Today, we’ll discuss ejection techniques for secondary overmoulds to help you solve this challenge with ease.

First of all, we need to understand the characteristics of the secondary overmould. This kind of mould in the injection process, the outer plastic material will wrap the inner material, forming a whole. Therefore, during the ejection process, it is necessary to ensure that the inner material is not damaged, but also to ensure that the outer material is intact. This requires us to fully consider the structure of the mould and the material characteristics when designing the ejection mechanism.

For the ejection of secondary overmoulding injection mould, we can adopt the following methods:

1. Reasonable design of ejector layout: the layout of the ejector should be reasonably designed according to the structure and size of the mould, to ensure that the ejector can be uniformly stressed, to avoid the occurrence of excessive local stress in the ejection process leading to mould damage.
2. Optimise the ejector force: the size of the ejector force directly affects the ejection effect of the mould. If the force is too small, the mould cannot be ejected smoothly; if the force is too large, the mould or product may be damaged. Therefore, we need to optimise the ejection force through practice to find the most suitable ejection parameters.
3. Adopt auxiliary ejector mechanism: For some complex secondary overmoulding injection moulds, we can consider adopting auxiliary ejector mechanism, such as slider, ejector and so on, in order to improve the ejection efficiency and ejection quality.

In addition, in order to ensure the smooth ejection of the mould, we also need to pay attention to the following points:

•    Keep the mould clean: clean the oil and impurities on the surface of the mould regularly to ensure that the ejector pin and ejector mechanism can work smoothly.
•    Check the wear of the mould: check the wear of the mould regularly, and replace the ejector pins and ejector mechanism with serious wear in time to avoid affecting the ejection effect.
•    Reasonable control of injection moulding process parameters: injection moulding process parameters also have a certain impact on the ejection of the mould. We need to reasonably control the parameters of injection temperature, pressure and speed according to the characteristics of the material and the structure of the mould to ensure that the mould can be ejected smoothly.

All in all, the ejection of secondary overmould is a process that requires comprehensive consideration of many factors. Through the reasonable design of the ejection mechanism, optimise the ejection force and the use of auxiliary ejection mechanism, we can effectively solve the ejection problems of the secondary overmoulding injection mould. At the same time, keeping the mould clean and checking the wear condition are also the key to ensure the ejection effect.