During the production and manufacturing of plastic parts, various defects may occur due to material properties, mold design, processing parameters, and other factors. Below is a summary of the common defects in plastic parts and corresponding countermeasures.
1. Warping and Deformation
- Cause:
Warping caused by material properties, poor plastic structure leading to uneven mold flow, and other factors. - Countermeasures:
- Ensure the rationality of the product structure during design to maintain uniform wall thickness.
- Optimize mold design, particularly the positioning of gates and runners, to ensure balanced mold flow.
2. Short Shots (Incomplete Filling)
- Cause:
Incomplete filling of plastic, which may be related to molding parameters, size and position of runners and gates, and product structure. - Countermeasures:
- Design the product and mold rationally.
- Adjust molding machine parameters appropriately to ensure sufficient filling.
3. Flash (Burrs)
- Cause:
Poor fit between mold components and the characteristics of the plastic material (e.g., flowability and cooling speed). - Countermeasures:
- Choose a reasonable gap for mold fitting based on the properties of the plastic material.
- Set appropriate molding parameters to minimize flash formation.
4. Scratches or Drag Marks
- Cause:
Excessive interference force between the product and mold during ejection, causing damage to the appearance or structure of the product. Other causes include burrs on the mold core. - Countermeasures:
- Increase the draft angle of the mold to facilitate ejection.
- Polish mold core components to reduce surface imperfections.
5. Burn Marks
- Cause:
Excessively high molding temperature or poor mold venting, causing overheating of trapped air. - Countermeasures:
- Set reasonable molding parameters to avoid overheating.
- Improve mold venting to allow trapped air to escape.
6. Cracking
- Cause:
- Poor product structure design leading to stress concentrations.
- Internal stress within the product after molding, causing damage at weld lines or weak points.
- Countermeasures:
- Optimize product structure design to reduce internal stress generation.
- Choose appropriate gate and runner designs (size and location) to minimize the impact of weld lines on the product.
7. Discoloration
- Cause:
Incorrect setting of molding temperature, leading to overheating or thermal degradation of the plastic material. - Countermeasures:
- Adjust the molding temperature settings correctly.
- Improve product structure design and increase holding pressure and molding time if necessary.
By identifying the root causes of these common defects and implementing the suggested countermeasures, manufacturers can significantly improve the quality and performance of plastic parts. Proper product design, optimized mold structures, and well-adjusted processing parameters are key to reducing defects and ensuring efficient production.