How to repair burrs in injection molding?

1, Reasons for the formation of flying edges
The emergence of flying edges mainly stems from the following aspects:
Mold factors: Unreasonable mold design, such as low precision of parting surface, excessive fit clearance, insufficient mold strength leading to deformation, etc., are all direct causes of flash.
Improper injection molding process parameters: excessive injection pressure, fast injection speed, insufficient clamping force, high mold temperature, and other factors may also lead to the occurrence of burrs.
Characteristics of plastic materials: Some plastic materials have good fluidity and are prone to overflow at the parting surface of the mold, forming burrs.
Machine malfunction: The injection molding machine itself has faults, such as decreased precision of the mold closing mechanism, unstable hydraulic system, etc., which may also lead to flash problems.
2, Preventive measures
Preventing the occurrence of flying edges is the primary task, and the following are some effective preventive measures:
Optimize mold design: Improve the accuracy of the mold parting surface, design the fitting clearance of the mold reasonably, and ensure that the strength and stiffness of the mold meet the requirements. At the same time, regularly check the wear and tear of the mold, and promptly repair or replace damaged parts.
Adjust injection molding process parameters: Based on the characteristics of plastic materials and product requirements, set reasonable process parameters such as injection pressure, injection speed, mold locking force, and mold temperature. Through experimentation and debugging, find the optimal combination of process parameters to reduce the occurrence of burrs.
Choose appropriate plastic materials: Whenever possible, choose plastic materials with moderate fluidity and low shrinkage to reduce the risk of flash.
Regular maintenance of injection molding machine: Maintain the good condition of the injection molding machine, regularly inspect and maintain key components such as the mold closing mechanism and hydraulic system to ensure their accuracy and stability.
3, Repair method
Although preventive measures can greatly reduce the occurrence of flying edges, flying edge problems may still be encountered in actual production. At this point, effective repair methods need to be taken to restore the quality and appearance of the product.
Manual trimming: For small areas of burrs, scissors, blades, or specialized trimming tools can be used for manual trimming. When trimming, be careful not to damage the surface of the product and keep the trimmed surface flat and smooth.
Mechanical polishing: For larger areas of burrs or situations that require higher precision repair, mechanical tools such as grinding wheels, sandpaper, or electric polishing machines can be used for polishing. When polishing, appropriate sand particle size and polishing direction should be selected to avoid new scratches or unevenness.
Chemical corrosion: In some cases, chemical corrosion agents can be used to remove burrs. This method requires strict control of the concentration and duration of the corrosive agent to avoid unnecessary damage to the product. At the same time, products that have undergone chemical corrosion need to be thoroughly cleaned and dried.
Ultrasonic cleaning: Ultrasonic cleaning technology can also be used to remove burrs. This technology utilizes the cavitation effect of ultrasound in liquid to generate strong shock waves and microjets, thereby peeling off the burrs and dirt on the surface of the product. Ultrasonic cleaning has the advantages of high efficiency, environmental friendliness, and no damage to the surface of the product.
Heat treatment: For certain plastic materials, their molecular structure can be altered through heat treatment to improve their flowability and shrinkage, and reduce the occurrence of burrs. However, it should be noted that heat treatment may affect other properties of the product, so sufficient testing and evaluation are required before use.