Die Adhesion, also known as StickingSpruesorParts, is due to poor injection nozzle and nozzle arc interface, the sprue material did not release together with the product and abnormal packing. Normally, the diameter of the main runner should be large enough so that the gate material is not yet fully cured at the time of mold release. Regardless of viscous flow channel, or products stuck in the mold cavity, poor mold release plastic injection is the most important killer, resulting in the root cause of mold release may be different parts of injection molding equipment, injection molding process may also be caused by improper. Although there is no artifact design and mold design errors caused by burrs, draft taper, pull the draft angle and other reasons, sometimes molded parts will appear demoulding poor. Forced to eject, often resulting in warping parts, after the top white or cracked. In particular, the molded part sticks to one side of the static mold and sometimes can not be ejected.
Analysis of Causes of Defective Die Adhesion and Solutions
1, mold failure There are many reasons for sticky mold and poor mold release, and mold failure is one of the main reasons. The causes and treatment methods are as follows: 1) The rough surface of the mold cavity, if the mold cavity and the flow path left with chisel marks, scars, scars and other surface defects, plastic parts will be very easy to adhere to the mold, resulting in demoulding difficulties. Therefore, should try to improve the mold cavity and runner surface finish, the best cavity surface chrome, polishing process, the direction of action of the polishing tool should be consistent with the melt filling direction. 2) Die wear or tear at the insert or the gap at the block is too large When the melt in the mold scratched parts or inserts within the flash gap, it will also cause demoulding difficulties. In this regard, should repair the lesion and reduce the insert gap.
3) lack of mold rigidity If the mold can not be opened at the beginning of injection, it indicates that the mold is deformed under the effect of injection pressure due to insufficient rigidity. If the deformation exceeds the elastic limit, the mold can not be restored to its original state, can not continue to use. Even if the deformation does not exceed the elastic limit of the mold, the melt cools and solidifies in the cavity under very high conditions to remove the injection pressure. After the mold is restored and deformed, the plastic part is clamped by the resilience and the mold still can not be opened. Therefore, in the design of the mold, you must design enough rigidity and strength. Test mode, it is best to install the dial indicator on the mold, check the mold cavity and the mold in the mold filling process is not deformed, the initial injection when the test injection pressure should not be too high starting point, should be observed while the mold deformation , While slowly raising the injection pressure, the deformation control in a certain range. When the rebound force is too large to cause clamping failure, only by increasing the mold opening force is not enough, the mold should be disassembled and decomposed, and plastic parts heated softened and removed. For the lack of rigidity of the mold, in the mold inlaid frame, improve rigidity.