4) demoulding slope is insufficient or moving, set the difference between the parallelism of the template In the design and production of mold, should ensure adequate demoulding draft, or plastic mold is difficult demoulding, forced ejection, often resulting in plastic parts warp, the top of the site whitish or cracked. Mold movement, set the template to be relatively parallel, otherwise it will lead to the cavity offset, resulting in poor demolding.
5) pouring system design is not reasonable If the runner is too long, too small, the main runner and sub-runner part of the connection strength is not enough, the main runner without cold material hole, poor balance of the gate, the main runner diameter and nozzle hole diameter with improper or sprue sleeve and nozzle The spherical surface does not match, will lead to sticky mold and mold release bad. Therefore, the length of the runner should be shortened and its cross-sectional area should be appropriately increased to increase the strength of the connecting part between the main runner and the runner. Cold material holes should be arranged on the main runner. Determine the gate position, you can increase the auxiliary gate and other methods to balance multi-cavity mold filling rate of each cavity and reduce the pressure within the cavity. Under normal circumstances, the mainstream end of the small diameter of the nozzle should be larger than the nozzle aperture 0.5 ~ 1mm, the concave circle radius of the sprue sleeve should be larger than the nozzle spherical radius 1 ~ 2mm.
6) The ejection mechanism design is not reasonable or improper operation If the ejector is out of range, the ejector is out of balance or the top plate is not moving well, it will result in the mold being unable to release the mold. In the circumstances permit, should try to increase the ejector effective ejecting area, to ensure adequate ejection stroke, plastic ejection speed should be controlled in the appropriate range, not too fast or too slow. The main reason for the poor action of the roof is due to the stickiness between the sliders. For example, when the roof pushes the slide core to move, the temperature of the slide core is higher than that of other cores because of no cooling device at the slide core. During the continuous operation, the gap between the pillar body and the slide core is extremely small, Bad, another example, when the pin holes and the top of the guide pin parallel to the poor or top pin bending, the roof will be bad action. If there is no pin in the pushing mechanism, when there is a foreign matter between the top plate and the mounting plate, the top plate is inclined, and then the top plate is not operated properly. In the large mold, if only a mandrel role, the roof can not be balanced thrust, will also have a poor action.
7) poor mold exhaust or mold core without air inlet can also cause sticky mold and mold release should improve the mold exhaust conditions, mold core should be set into the air inlet.
8) improper mold temperature control or cooling time is not appropriate
If the parting surface is difficult to mold release, the mold temperature can be increased and shorten the cooling time. If the cavity surface is difficult to mold release, may be appropriate to reduce the mold temperature or increase the cooling time. In addition, the fixed mold temperature is too high, can lead to poor demoulding. Mold cavity material is porous soft material will cause sticky mold. In this regard, should be replaced by hard steel or surface plating. 9) runner out of bad, no pull fishing gate institutions. Sub-surface below the concave, the cavity line more than the mold line and other mold defects will affect the degree of mold release in this regard, it should be noted and be trimmed.