Several Points to Pay Attention to When Designing Plastic Molds

Plastic molds are tools that are used in the plastic processing industry to match plastic molding machines and give plastic products a complete configuration and accurate size. Due to the wide variety of plastic varieties and processing methods, and the varying structures of plastic molding machines and plastic products, the types and structures of plastic molds are also diverse. So, what key points should we pay attention to when designing plastic molds?

1. Mold opening direction

After the mold opening direction is determined, you can choose an appropriate parting line to avoid undercuts in the mold opening direction to improve the appearance and performance.

After the mold opening direction is determined, the product's reinforcement ribs, buckles, protrusions and other structures should be designed to be consistent with the mold opening direction as much as possible to avoid core pulling to reduce the stitching line and extend the mold life.

2. Product wall thickness

Uneven wall thickness will cause pores and weld marks.

Uneven wall thickness will cause shrinkage on the surface of plastic products.

All kinds of plastics have some wall thickness ranges, generally 0.5~4mm. When the wall thickness exceeds 4mm, it will cause too long cooling time and shrinkage problems. You should consider changing the product structure.

3. Buckle position

Design the buckle position device of the plastic mold to share multiple buckles at the same time, so that the overall device will not fail to operate due to damage to individual buckles, thereby increasing its service life, and then consider adding fillets to increase strength.

The tolerance requirements for the buckle-related dimensions of the plastic mold are very strict. Too many undercut positions are prone to buckle damage; on the contrary, too few undercut positions make it difficult to control the assembly position or the combined part is too loose. The solution is to reserve a way to easily add glue for mold modification.

4. Demolding slope

Appropriate demoulding slope can avoid product hair pulling (drawing). The demoulding slope of the smooth surface should be ≥0.5 degrees, the surface of fine leather grain (sand surface) should be greater than 1 degree, and the surface of rough leather grain should be greater than 1.5 degrees.

Appropriate demoulding slope can avoid product top damage, such as top whitening, top deformation, and top breakage.

When designing deep cavity structure products, the outer surface slope should be greater than the inner surface slope as much as possible to ensure that the mold core is not offset during injection molding, obtain uniform product wall thickness, and ensure the material strength of the product opening.

5. Reinforcement Ribs

The reasonable application of reinforcement ribs can increase product rigidity and reduce deformation.

The thickness of the reinforcement ribs needs to be ≤ (0.5~0.7)t product wall thickness, otherwise it will cause surface shrinkage.

The single-sided slope of the reinforcement rib should be greater than 1.5° to avoid top injuries.

Qingdao Xueyu Molding Products Co., Ltd. is mainly engaged in the design and manufacturing of injection molds, injection molding and secondary processing (spraying, pad printing, ultrasonic welding, stamping), etc. For more information about plastic mold, please contact us.

Website: www.xyzmould.com

Address: No.18 Henan Head Road, Henan Head Community, Jihongtan Street, Qingdao Industrial Park, Shandong Province, China

Email: wangmiaotian8@163.com