In the injection molding of injection molds, cracks in plastic products are a very common problem. So, what should we do to eliminate the cracks in injection mold products?
Causes of cracks in plastic products
- 1. Residual stress (oversaturated mode) caused by molding setting conditions;
- 2. Residual stress occurring during demoulding;
- 3. Stress concentration caused by the shape of the product;
- 4. Error caused by thermal expansion of the same insert;
- 5. Deterioration of materials.
Associated knowledge
- 1. The metal inserts are pre-heated to relieve the residual stress during forming. For the same principle, it is also a method to replace the inserts with annealing after forming
- 2. Among the molding setting conditions, the measure of reducing injection pressure is the most effective;
- 3. If the demolding pins are balanced separately, a larger force is added to the demolding.
Solution to eliminate cracks in injection mold products
- 1. Instant: increase the temperature of the barrel, reduce the injection pressure, and reduce the demolding speed;
- 2. Short-term: improve the mold cavity finish;
- 3. Long-term: The release angle should be sufficient, the release pins should be balanced, the product should not be designed with sharp angles, and the thickness of the product should be avoided as much as possible.
Material difference
- 1. Because polycarbonate (PC) PVC and other materials are easy to stick to the chrome layer of the mold, especially in the corners become inverted cones, so pay attention;
- 2. Polycarbonate (PC) is prone to cracks in the mold insert. In such cases, it is better to add reinforced glass fibers to the material.
Dongguan PTJ Precision Plastic Products Co., Ltd. has been focusing on injection molds for 10 years. The yield of injection molded products has reached 100%. It is a professional one-stop manufacturer of injection molds, injection mold opening, injection mold injection, spray processing, silk screen injection and assembly to assembly. Service of injection mold factory.
Dongguan PTJ Precision Plastic Products Co., Ltd. was established on November 28, 2006. It is located at the foot of Daling Mountain with clear water and fresh air in Dongguan. It is close to the national highway and has convenient transportation. There are more than 500 employees, including 70 mold technicians and 35 quality control personnel. It has formed a perfect industrial chain with an annual output of several hundred million yuan for mold injection and spray assembly.