In the injection molding process, the ejection mechanism plays a vital role. Also known as the demolding or push-out mechanism, it is the final step in the molding cycle, responsible for accurately ejecting the molded part. So, what are the core principles to follow when designing this crucial mechanism?
Accuracy and Reliability
Firstly, the direction of motion of the ejection mechanism must be accurate and reliable, with no stalling throughout the process. The mechanism itself needs sufficient strength and stiffness to withstand the resistance generated during demolding, ensuring smooth ejection.
Protecting the Molded Part from Deformation
Secondly, a fundamental requirement when designing the ejection mechanism is to protect the molded part from deformation. The distribution of ejection force should be as close to the core as possible, and the area of action should be increased. This effectively prevents the molded part from deforming or being damaged during ejection. Typically, we apply the ejection resistance to areas less prone to deformation, such as reinforcing ribs, flanges, or thick walls. When calculating the ejection force, factors like the adhesion of the molded part to the mold, and the shape and surface roughness of the part, should be fully considered.
Simplifying the Design
Furthermore, to simplify the ejection mechanism design, we generally ensure the molded part remains on the moving side of the mold after opening. This principle reduces the complexity of the ejection mechanism and improves the efficiency of mold manufacturing and use.
Considerations for Usage or Assembly Reference Surfaces
Lastly, when the ejection point needs to be located on the usage or assembly reference surface of the molded part, special attention should be paid to avoiding any impact on the dimensions and performance. The contact area between the ejector pin and the molded part should be appropriately recessed. The end face of the ejector pin should be higher than the reference surface to ensure the surface of the molded part is flat without protrusions, maintaining the appearance and quality.
Tips from Yize Mould Engineers:
The above tips are accumulated by the engineers of Dongguan Yize Mold Co., Ltd. in their design of ejection mechanisms for injection molds. They hope to provide useful references for their peers.
About Yize Mould:
Founded in 2007, Yize Mold is located in Dongguan, the manufacturing capital, with a strategic location and convenient transportation. As a company engaged in precision mold design and manufacturing, as well as precision injection molding products production for many years, we specialize in:
- Design, precision mold manufacturing, injection molding, and assembly.
- After-sales service for products such as automotive connectors.
- Medical product injection molding, cleanroom injection molding.
- PFA custom injection molding, and more.
For more information or to inquire about cooperation, please call +86 13302615729 (WeChat, WhatsApp same number). We will serve you sincerely.
