10 common problems and solutions in the injection molding process

Guangdong Precision is committed to providing customers from all walks of life around the world with one-stop solutions for precision metal stamping, metal drawing and metal insert injection molding. In the first two articles, we introduced a total of 20 problems and countermeasures in the injection molding process. In this article, our engineers summarized 10 problems and solutions, and hope to help you. 1. Requirements for hydraulic oil for injection molding machine: (1) Proper viscosity and good viscosity performance (2) Good lubricity and rust resistance (3) Good chemical stability, not easy to gasify into gum (4) Good foaming (5) Corrosion to mechanical parts and sealing devices should be small (6) Ignition point (flash point) requirements, freezing point should be low. 2. What is the influence of hydraulic oil viscosity on injection molding machine? When the temperature of the working environment of the system is high, the oil with higher viscosity should be used. On the contrary, the oil with lower viscosity should be used. When the working pressure of the system is higher, the oil with higher viscosity should be used, because at high pressure, it is difficult to seal and leak. Is the main problem; on the contrary, the working pressure of the system is low, and it is better to use oil with a low viscosity. When the working parts of the hydraulic system are running at a high speed, the flow rate of the oil is also high. At this time, the pressure loss will also increase, and the leakage will be relatively high. To reduce, it is advisable to use oil with lower viscosity. On the contrary, when the moving speed of working parts is low, oil with higher viscosity should be used. 3. Loosen the setting. The correct position of the loosening and retreat u003d the moving position of the rubber ring + the screw offside distance. 4. Setting of melt position u003d product weight/(maximum stroke/maximum melt volume) 5. Main advantages of gas-assisted injection molding (GAM) It can evacuate the core of thick materials to make hollow pipe fittings. Save materials and shorten cycle time. The use of gas in injection molding can make the pressure evenly distributed. When the plastic cools and solidifies, the gas can compensate for the volume shrinkage of the plastic through expansion. Reduce the internal stress of the molded product, thereby improving the stability of the shape, eliminating deformation and warpage. 6. The outer diameter of the piston rod is small in the middle, and the two ends are big problems? Due to the uneven shrinkage of the product due to the overheating of the center hole needle, the outer diameter of the piston rod is small in the middle and the two ends are large. The center hole needle can be made of phosphor copper material with fast heat dissipation, and the mold is exhausted in the middle of the product. 7. The problem of cracking after screen printing on spherical surface Due to the stress on the surface of the product, cracking after screen printing is caused. Increase mold temperature and reduce stress. Annealing method can be used to eliminate stress. 8. Transparent PC shell bubble problem. The raw material is not dried enough, the product has uneven glue thickness, poor mold exhaust, and easy decomposition of raw materials may cause product bubbles. Fully dry, increase the mold exhaust, and minimize the uneven thickness of the glue. 9. The problem of easy breaking of the nozzle edge of the spectacle frame. The injection pressure and the holding pressure of the large nozzle remain internal stress, which causes the product to break easily. Reduce the injection pressure and holding pressure as much as possible, and appropriately increase the mold temperature to solve it. 10. The four pillars of the electrical enclosure are prone to bursting when screwing. The product assembly pillars are prone to bursting due to the existence of water clamping lines in the pillars. The mold increases the exhaust gas, appropriately increases the mold temperature, and accelerates the injection speed to reduce the water clamping line. [Related recommendation] Learn more: 精の corporate culture Learn more: Continuous improvement and innovation are the key factors for the survival of stamping companies Learn more: Why most stamping factories are unwilling to quote foreign trade companies