Understanding of Injection Mold Deformation
Mold deformation is a common production issue that directly impacts product quality and production efficiency.
Causes of Mold Deformation
Mold Design Flaws:
Insufficient Venting: Gases trapped within the mold cavity cannot be effectively evacuated, leading to excessive pressure and mold deformation.
Inadequate Cooling System Design: Poor cooling results in incomplete solidification of the molten plastic within the cavity, causing thermal expansion of the mold.
Improper Selection of Mold Steel: The mold steel lacks sufficient hardness and heat resistance, leading to deformation under high temperature and pressure.
Processing Defects:
Insufficient Machining Precision: Excessive gaps between mating mold components can cause relative movement during injection molding, resulting in deformation.
Improper Heat Treatment: Inadequate heat treatment results in insufficient hardness and toughness of the mold, leading to deformation.
Improper Injection Molding Process Parameters:
Excessive Injection Pressure: Excessive injection pressure subjects the mold to greater force, increasing the likelihood of deformation.
Excessive Holding Time: Prolonged holding time allows the molten plastic to remain in the cavity for an extended period, resulting in incomplete cooling and thermal expansion of the mold.
Insufficient Cooling Time: Insufficient cooling time prevents the plastic part from fully solidifying and can cause deformation during ejection.
Solutions to Mold Deformation
Mold Design Improvements:
Optimize Venting System: Increase the number and location of vents to ensure smooth evacuation of gases from the mold cavity.
Improve Cooling System: Increase the number of cooling channels to enhance efficiency.
Select Appropriate Mold Steel: Choose mold steel based on the type of plastic and processing conditions.
Processing Improvement:
Enhance Machining Precision: Strictly control the machining precision of mold components to ensure proper clearances.
Optimize Heat Treatment Process: Select appropriate heat treatment processes based on the properties of the mold steel to improve hardness and toughness.
Adjust Injection Molding Process Parameters:
Reduce Injection Pressure: Reduce injection pressure as much as possible while maintaining product quality.
Shorten Holding Time: Shorten holding time to reduce the residence time of molten plastic in the cavity.
Extend Cooling Time: Extend cooling time to ensure complete solidification of the plastic part.
