Common injection molding problems and solutions

author: Universe plastic

2023-12-27

Injection molding, as an important process method for manufacturing plastic products, faces various challenges and problems brought by all industries.

This article will delve into common problems in injection molding production and provide corresponding solutions to help manufacturers in the plastics industry better cope with difficulties and create more perfect plastic products.

1. There are bubbles in injection molded parts

Problem description: Bubbles appear inside or on the surface of plastic products.

Solution:

① Increase injection pressure and speed to ensure plastic fluidity.

② Reduce the mold temperature to avoid overheating and decomposition of plastic.

③Improve the drying process of raw materials to ensure sufficient drying of raw materials.

Learn more: Solution to Injection Molding Bubbles

2. Injection molded parts have shrinkage marks

Problem description: The surface of the plastic product appears dented or uneven.

Solutions:

① Increase the holding pressure and cooling time to ensure that the plastic completely fills the mold.

② Increase the mold temperature and reduce plastic shrinkage.

③Adjust product design to increase wall thickness uniformity and avoid uneven thickness.

Learn more: Injection Molding Sink Mark Solution

3. Injection molded parts are burnt.

Problem description: Black or brown burn marks appear on the surface of plastic products.

Solutions:

① Reduce the injection speed and pressure to avoid overheating of the plastic.

② Check and clean the mold exhaust system to ensure good exhaust.

③Reduce the temperature of the barrel to prevent overheating and decomposition of plastic.

4. Injection molded parts have too many burrs

Problem description: Excess flakes or burrs appear on the parting surface of plastic products.

Solutions:

① Check the mold parting surface to ensure tight closure and avoid gaps.

②Adjust injection pressure and speed to avoid excessive extrusion.

③Replace or repair worn mold parts to ensure mold accuracy.

Learn more: Injection molding burr solution

5. Injection molded parts have obvious weld marks

Problem description: Welding marks appear on the surface of plastic products, affecting the appearance and strength.

Solutions:

①Increase the mold temperature and injection speed to ensure that the plastic is fully integrated.

②Improve the location and design of the gate and optimize the location of the welding point.

③Adjust the material formula and use better fluid materials.

Learn more:

6. Injection molded parts have uneven color.

Problem description: Color unevenness or streaks appear on the surface of the product.

Solutions:

① Ensure that the raw materials and masterbatch are mixed evenly to avoid delamination.

②Clean the injection molding machine and screw to avoid residue contamination.

③Control the injection molding temperature and speed to avoid overheating and decomposition of the plastic.

Learn more: Solution to uneven color of injection molding

7. Injection molded parts have warpage.

Problem description: The product deforms or twists after cooling.

Solutions:

① Cool evenly to avoid local cooling too fast.

②Adjust the mold design, add a cooling circuit, and improve cooling efficiency.

③Increase the holding time to ensure that the product is completely cooled and finalized.

8. Short shot during injection molding

Problem description: The product is not completely filled, resulting in material shortage.

Solutions:

① Increase the injection volume and injection speed to ensure that filling is in place.

② Increase the mold temperature and barrel temperature to improve plastic fluidity.

③ Check and clean the mold gate and runner to ensure smooth flow.

Learn more: Injection molding short shot solution

9. Injection molding has a high scrap rate

Problem description: The scrap rate in production remains high, leading to resource waste and increased production costs.

Solutions:

① Regularly check the parameters of the injection molding machine to ensure that parameters such as temperature, pressure and injection speed are correct.

② Carry out mold maintenance to prevent wear and deformation.

③Implement strict quality control processes to promptly detect and handle abnormalities in production.

10. Injection mold wear

Problem description: During injection molding, the mold is worn, which affects the quality and accuracy of the product.

Solutions:

①Implement a regular mold maintenance plan to clean and lubricate the mold surface.

②Choose highly wear-resistant mold materials to improve the durability of the mold.

③Avoid excessive injection pressure and temperature during production to reduce the impact on the mold.

11. Injection molding efficiency is slow

Problem description: The injection molding cycle is long, the production efficiency is slow, and the delivery time is affected.

Solutions:

① Optimize the production process and improve the operating efficiency of the injection molding machine.

② Use advanced injection molding technology, such as rapid injection and automated control, to shorten the production cycle.

③Plan production plans reasonably to avoid production bottlenecks.

12. Waste of injection molding materials

Problem description: There is serious waste of raw materials during injection molding production, which increases manufacturing costs.

Solutions:

① Use recyclable injection molding materials to reduce the impact on the environment.

② By improving the parameters of the injection molding process, the scrap rate is reduced and the utilization rate of raw materials is improved.

③Carry out employee training to improve the skills of operators and reduce waste caused by misoperation.

13. Environmental compliance issues

Problem description: The injection molding industry is facing increasingly stringent environmental regulations, and companies need to meet relevant requirements.

solution:

① Use environmentally friendly materials to reduce environmental pollution.

② Establish a complete environmental protection management system to ensure the safe disposal of waste.

③Maintain close cooperation with relevant departments to keep abreast of and comply with the latest environmental regulations.

Finally, the engineering team of Dongguan Universe Plastic Co., Ltd. recommends that when the above injection molding problems occur, the above solution ideas can be used as a reference for suggestions.

The specific situation may also be affected by various factors such as materials, molds, and manufacturing conditions.

Details require you to adjust and improve according to your actual situation.

In injection molding manufacturing, accumulate your own injection molding production experience by carefully analyzing and solving these common problems.

Injection molding manufacturing companies can better improve production efficiency, reduce costs, and better adapt to changes in market demand and serve customers.

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