Injection Molding Products,Solution Insufficient Strength and hardness
Insufficient strength, hardness, or cracking of plastic mold products are generally caused by local cracking of plastic mold products due to external forces, which seriously affects the overall effect of plastic mold products. The occurrence of such phenomena is a fatal defect for a plastic product and needs to be completely eliminated,
Cracking of injection molded plastic products is generally accompanied by discoloration of the product. Mainly reflected in the following points:
1. The injected product cracks directly; 2. Cracking during bending test; 3. Cracking during product assembly process; 4. Cracking in extreme usage environments.
Analysis of the reasons for insufficient strength or cracking of injection molded plastic products:
1. Product design factors: Whether the structure of injection molded products is reasonable and whether there are stress concentrations caused by sharp corners; Whether the product wall thickness is uniform and the strength is insufficient; 2. Material factors: whether the material itself is brittle, whether the material is mixed with recycled materials or contains other impurities and solvents; 3. Injection mold factors: whether the mold gate size is reasonable; Is the position of the mold ejector or the size of the ejector pin reasonable; 4. Injection molding process factors; Whether the melting pressure and speed settings are appropriate; Whether the temperature and time settings are appropriate; 5. Injection molding machine factors: whether the dwell time in the equipment is too long, and whether the ejector rod is balanced.
In terms of injection molded plastic product design:
1. The product has sharp corners with stress cracking or significant differences in thickness; 2. The product is too thin or hollowed out too much, resulting in insufficient strength.
In terms of raw materials for injection molded plastic products:
1. The raw materials contain other impurities or are doped with inappropriate solvents; 2. Plastic will undergo catalytic cracking reaction with water vapor when heated under damp conditions; 3. Plastic is heated for too long inside the material tray.
Solution sharing for insufficient strength and hardness of injection molded plastic products in mold production and processing
4. The performance of plastic itself is insufficient.
In terms of plastic molds from mold manufacturers:
1. The gate is too small; 2. The diversion channel is too small or improperly configured; 3. Abnormal injection cycle caused by poor mold structure; 4. Unreasonable ejection design or ejection conditions.
In terms of injection molding processing by plastic mold manufacturers:
1. The temperature of the material cylinder and nozzle is too low; 2. Reduce screw back pressure and rotational speed to minimize plastic degradation caused by shear overheating; 3. Mold temperature is too high, making demolding difficult; The mold temperature is too low, the plastic cools too early, the fusion joint is poor, and it is easy to crack.
In terms of injection molding equipment from injection molding manufacturers:
1. There are obstacles inside the material barrel, which can easily exacerbate plastic degradation; 2. Insufficient or excessive plasticization of the injection molding machine results in insufficient plasticization of the plastic in the barrel or prolonged plasticization time; 3. The ejection device is tilted or unbalanced.
Solution sharing for insufficient strength and hardness of injection molded plastic products in mold production and processing
Solution
Product Design: 1-2 Change the product structure to ensure smooth transitions and uniform wall thickness.
Raw materials: 1. Pay attention to keeping the materials clean. 2. Ensure the baking time of the materials. 3. Reduce the residence time of materials in the material tray. 4. Choose high-strength plastic.
Plastic mold: 1. Increase the gate size. 2. Increase the size of the main and branch channels. 3. Try to ensure even cooling and stable cycle. 4. Adjust the top pin position according to the product structure.
Injection molding process: 1. Reduce the temperature of the barrel and nozzle. 2. Reduce back pressure, screw speed, and injection speed to minimize the generation of excessive shear heat. 3. If the brittleness is caused by insufficient strength of the fusion line, the strength of the fusion line can be improved by increasing the melt temperature and injection pressure.
Injection molding machine: 1. Regular maintenance of equipment. 2. Choose the appropriate injection molding machine. 3. Regularly maintain the ejector mechanism and replace vulnerable parts in a timely manner.
