7/25/2023 0 Comments Preform pet![]() The structure size of the commonly used blank holder and remaining material trough is shown in the figure.Plastic PET Preform Injection Molding Troubleshooting The width of the clamping blank is generally 1~2mm, and the angle is 13°~15°. Its size should be determined according to the width and thickness of the remaining material after the preform is clamped, and the mould can be closed tightly. The remaining material groove is usually set on the upper and lower sides of the cut. There may be inadequate clamping, continuous preform cutting, or insufficient joint strength after preform cutting. In that case, the joint surface will not fit tightly, and the remaining trough capacity will be insufficient. Suppose the width and angle of the clamping blank are not appropriate. In addition to cutting off the remaining material, the clamping blank also clamping the closed preform. For this reason, opening a surplus slot in the corresponding position to accommodate the blank opening and the structural size of the surplus slot are the key to the design of the extrusion blow mould. The remaining material of the preform cut by the cutting edge falls on the parting surface, affecting the mould’s closing. Extrusion blow moulding mould needs to cut off the remaining material simultaneously, so the corresponding part of the mould must be set with the blank opening. The blank mouth is also called the cutting edge. ![]() For deep grooves with smaller slopes, side parting mechanisms should be setĬlamping mouth and remaining material trough In addition, the demolding temperature is high, the elasticity is good, and it can be forced to demold. Side parting: To make the wall thickness as uniform as possible for blow moulded products, a more significant slope is used for a gradual transition even if there are undercuts. The product cavity should be polished for a high gloss, high transparency, and other special requirements.Ĭ. The container handle is generally set on the parting surface.ī cavity surface: low blowing pressure, low moulding temperature, plastic will not enter the trough of microscopic unevenness (roughness), relatively rough profile, not only will not affect the surface state of the product but also facilitate exhaust. For products with complex shapes, the parting surface can be a curved surface or a combination of multiple planes. For example, the extrusion blow mould has a blank opening and a remaining material slot the air inlet rod of the stretch blow mould is controllable and expandable, and so on.Ī Parting surface: usually, the plane passes through the most significant part of the profile of the product section. The specific structure of the blow mould varies with the design of the plastic part and the blowing method of the preform type. In addition, similar to other two-half cavity moulds such as injection moulds, compression molds, and transfer moulds, the blow mould also has a mould clamping guide positioning mechanism, a cooling system, and an exhaust system. This is a hallmark feature shared by blow moulds. ![]() There is only a cavity (regardless of unevenness) of the outer shape of the moulded product and no core there is an air inlet between the two mould halves Rod or intake needle. Therefore, the blow moulder’s moulds are mostly two halves or multiple moulds (when side parting is required). Only the blow moulder mould’s external structure size is limited, and the internal structure size depends on the shape. Here we mainly discuss the narrow sense.īlow molding process mould-blow molding mold is referred to as blow mould.As mentioned above, the hollow product is formed by injecting compressed air into the high-temperature preform and pressing it against the surface of the mould cavity by the air pressure in the preform. ![]() ![]() The preform moulding die (extrusion die, injection die) has been mentioned above. ![]()
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