Injection molding companies need to promptly identify problems that arise during the plastic molding process, propose corresponding solutions, and promptly resolve operational and machine failures to reduce injection molding costs and improve production efficiency. The following are common problems that occur during the injection molding process and the solutions that most injection molding companies adopt:

-Warping Deformation

1. Imbalanced Molecular Orientation. The most effective way to reduce the warping deformation caused by molecular orientation differences is to lower the temperature of the melt and mold. When using this method, it is best to combine it with the heat treatment of the plastic part, otherwise, the effect of reducing molecular orientation differences will be relatively short-lived. The method of heat treatment is to place the plastic part at a higher temperature for a certain period after demolding, and then slowly cool it to room temperature, which can significantly eliminate the orientation stress inside the plastic part.
2. Improper Cooling. When designing the structure of plastic parts, the cross-sectional thickness of each part should be as consistent as possible. The curing and shaping time of the plastic parts in the mold must meet the requirements. Cooling pipes should be installed in areas where the temperature is prone to rise and heat is concentrated.
3. The Design of the Mold Pouring System is Unreasonable. When determining the gate position, it is necessary to prevent the direct impact of molten material on the core, and to ensure that both sides of the core are evenly stressed; For rectangular flat plastic parts with larger areas, when using resin materials with larger molecular orientation and shrinkage, thin film or multi-point gates should be used, and radial gates should be avoided as much as possible; For ring-shaped plastic parts, disc or spoke type gates should be used, and radial or needle gates should be avoided as much as possible; For shell shaped plastic parts, straight gates should be used instead of parallel gates as much as possible.
4. Unreasonable Design of Mold Demolding and Exhaust System. In terms of mold design, the demolding angle, top rod position, and quantity should be reasonably designed to improve the strength and positioning accuracy of the mold; For small and medium-sized molds, reverse warping molds can be designed and manufactured based on the warping pattern. In terms of mold operation, the ejection speed or ejection stroke should be appropriately slowed down.

-Under Injection

1. Improper equipment selection. Wheninjection moldingcompanies choose injection molding equipment, the weight of the plastic parts must be smaller than the maximum injection volume of the injection molding machine. The total amount of injection (including other waste) cannot exceed 85% of the plasticization amount of the injection machine.
2. Insufficient supply of materials may result in bridging at the bottom of the feeding port. The injection stroke of the injection rod can be appropriately increased to increase the feeding amount.
3. Excessive lubricant. Reduce the amount of lubricant used and adjust the gap between the material barrel and the injection rod to repair the equipment.
4. Cold material impurities block the flow channel. The nozzle should be disassembled and cleaned, or the cross-section of the cold material cavity and flow channel of the mold should be expanded.

-Fusion Mark

1. The material temperature is too low. The main reason for the easy formation of fusion marks is the poor flow and convergence performance of low-temperature molten materials. If fine lines are formed on the inner and outer surfaces of plastic parts at the same location, it is often due to poor fusion caused by low material temperature. In this regard, the temperature of the material barrel and nozzle can be appropriately increased, or the injection cycle can be extended to promote an increase in material temperature. At the same time, the amount of coolant passing through the mold should be controlled, and the mold temperature should be appropriately increased.
2. Mold defects. It is advisable to use gate forms with less diversion and choose gate positions reasonably to avoid inconsistent filling rates and interruptions in the filling material flow. If possible, a small amount of adhesive should be used. To prevent the injection of low-temperature molten material into the mold cavity and the formation of welding marks, a cooling material hole can be installed inside the mold while increasing the mold temperature.
3. Poor mold exhaust. When problems arise due to this reason, the mold exhaust hole should be checked for blockage by solidified material or other objects from the melt, or for foreign objects at the gate. If carbonization points still appear after removing the blockage, exhaust holes should be added at the mold material collection point, the gate can be repositioned or the clamping force can be appropriately reduced. Auxiliary measures such as reducing material temperature and mold temperature, shortening high-pressure injection time, and lowering injection pressure can also be taken to solve the problem.
4. Improper use of release agent. In general, release agents are only used in small amounts in areas such as threads that are difficult to release, and should be used as little as possible in other areas.
5. Unreasonable structural design of plastic parts. If the wall thickness of the plastic part is designed to be too thin or there is a significant difference in thickness, as well as too many embedded parts, it can cause poor fusion. When designing the shape and structure of plastic parts, it should be ensured that the thinnest part of the plastic part must be greater than the minimum wall thickness allowed during molding. In addition, the use of inserts should be minimized as much as possible and the wall thickness should be as consistent as possible.