Today I saw an injection molded product that is an inner cover with a diameter of 150MM. Its internal structure is quite unique, with 14 buckles evenly distributed on inner ring of product. Clever design of these buckles adds to functionality of product.
Another important feature of product is undercut design of its inner circumference. This design allows for a snug fit. However, this design also brings certain challenges, because undercut design of inner circumference makes space very limited, and traditional inclined top inner row mold ejection method cannot be applied.
Therefore, when producing this product, we need to use special molds and processes to ensure product quality and smooth production.

Under condition of space limitation, we have to consider using shrink structure. However, the way in which shrink structure is actuated requires careful consideration to ensure that it can work effectively in a confined space. At the same time, we must ensure that shrinking movement does not interfere with ejection of ejector pin, otherwise it will affect quality of product and smooth progress of production.
In order to simplify mold structure and improve its practicality, we need to conduct sufficient research and design. We can consider using sliding modules, block mold cores, side core pulling and other structures to reduce complexity of mold, improve its maintainability.
When drawing, we also need to fully consider cost of mold. Standardized parts and simple structures can be used to reduce mold manufacturing costs. At the same time, positions of mold core, ejector pin, slider and other components should be reasonably arranged to reduce overall size and weight of mold, thereby further reducing costs.

Considering undercut design of inner circumference of product, a feasible solution is to design slider structure on product. This slider structure allows underbuckle to slide out smoothly during movement.
In addition, structural design of slider also needs to consider how it cooperates with undercut. How to ensure that slider can smoothly come out of undercut without affecting the overall performance of product is an important issue that needs to be solved.

In slider structure, we plan to design a puller block that is connected to slider through a T-slot for driving. This design not only enhances driving ability of slider, but also uses T-slot as a movement guide to ensure precise movement of slider. Each slider will be independently designed with guide grooves to meet needs of different directions and positions.
During design process of T-slot, we paid special attention to choice of processing method. In order to obtain the best processing results, we recommend using wire cutting processing. This method can avoid sparks and reduce processing costs.

 

In order to drive slider to move toward middle and release product from undercut, we plan to design puller block into a structure that can move downward. Through connection between horizontal slide block and T-slot, pull block can effectively drive slide block. After pull block moves downward, we plan to design it so that only 2/3 of length of tube is left to facilitate reset. At the same time, in order to ensure smooth installation and avoidance of pull block, we need to pay attention to leaving enough space. This design ensures that pull block remains stable during movement and effectively drives slide block, thereby achieving smooth installation and removal of product.