How to Avoid Product Deformation in Mold Designs?

Selection of Suitable Materials

Characteristics of Plastic Materials

Each plastic material has its specific coefficient of thermal expansion, shrinkage, and mechanical properties. Choosing materials with lower shrinkage and higher thermal stability can effectively reduce the risk of deformation. For example, for products requiring high dimensional accuracy, consider materials such as PA6+GF, which have a low shrinkage rate and good resistance to deformation.

Uniform Material Properties

If the material properties are not uniform, inconsistent shrinkage will result, which will trigger warping or deformation of the product. Therefore, before injection molding, ensure that the raw material is dry and uniform while avoiding using backing materials as much as possible.

Optimization of Mold Structure Design

Reasonable Wall Thickness Design

Uneven wall thickness is one of the main causes of product deformation. Thinner wall thicknesses cool faster, while thicker areas cool slower, resulting in different shrinkage rates in other parts of the mold, which ultimately leads to deformation. Therefore, the mold designs should try to keep the product wall thickness uniform, to avoid excessive differences in thickness.

Reasonable Reinforcement

Reinforcement can effectively improve the structural strength of the product, but improperly designed reinforcement will lead to stress concentration, which will cause warping or deformation. When designing reinforcement, it should be noted that its thickness should not exceed 60% of the wall thickness of the product, and try to avoid sharp angle design.

Optimize the Parting Surface and Gate Position

The position of the parting surface and gate has a great influence on the molding process. Asymmetric gate design may lead to uneven filling, which may cause deformation. During the design process, symmetrical or multi-point gates should be selected to ensure uniform filling of the molten plastic.

Optimize the Cooling System

Uniform Cooling Effect

Uneven cooling is one of the important factors causing deformation. The cooling system design should ensure that the temperature of each part of the mold is uniform. For example, multiple cooling pipes can be used and cooling channels can be added in thick-walled areas.

Control of Mold Temperature

The control of mold temperature is critical to the molding quality of the product. Too high or too low mold temperature may lead to product deformation. In actual production, a suitable mold temperature range can be set according to the characteristics of the material and precisely controlled by a mold thermostat.

Reasonable Setting of Process Parameters

Injection Pressure and Speed

Excessive injection pressure or speed may cause the molten plastic to fill up too quickly, which may trigger internal stresses and lead to product deformation. Injection pressure and speed should be adjusted according to product and material characteristics to ensure smooth melt flow.

Holding Pressure and Cooling Time

Insufficient holding time may lead to uneven shrinkage of the product, while too long a holding time will increase stress accumulation. Therefore, it is necessary to set reasonable holding pressure and cooling time according to the size of the product and material properties.

Other Auxiliary Measures

Post-treatment of Molds

In some cases, mold parts require surface treatment or heat treatment to improve their hardness and stability, thus reducing the possibility of deformation.

Product Post-treatment

For some products with high precision requirements, internal stresses can be further eliminated by annealing or calibration after injection molding is completed to avoid subsequent deformation.

The solution to the problem of product deformation requires all-around optimization from material selection, mold designs, and cooling systems to processing technology. Through rational mold designs and precise control of each link, the risk of deformation can be effectively reduced, and product quality and production efficiency can be improved. If you need a customized mold project, please feel free to contact our team!