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How to set process precision injection molding processing to the mold requirements
by：CSSSLD
2021-01-23
Precision injection molding processing plant is usually accomplished by injection molding machine and mold, and mold is in the above parts, it will directly affect the produce of the quality of the goods, so the injection molding processing usually has a high request on the accuracy of the mold.
here are several aspects for precision injection molding processing mold precision request to give us a detailed answer.
1, precision injection molding processing plants to the request of the scale, this is wonderful, have bigger errors of the scale of the mold, the output by the errors of the scale of the natural goods would exist.
2, roughness of precision injection molding processing factory appearance request, if the appearance of the mould can't smooth and detailed, the output of goods will be relatively coarse, needs polishing again and even scrapped directly, this directly affects the working efficiency of the company.
3, precision injection molding processing factory to the request of the density, under normal circumstances, the higher the density of the mold the confined ability is stronger, injection molding processing factory also is not easy deformation, so tricky to mould density selected also.
plastic mold precision injection molding processing, should be first selected engineering plastic material, and can perform engineering plastics and precision injection must choose those high mechanical properties, dimension stability, creep resistant performance is good, environmental stress cracking resistance of the material.
in the machining process, factors influencing the precision of injection molding products mainly from the temperature of the mold, injection molding process control, and the scene of the production environment temperature and humidity change amplitude and the acquired product annealing treatment, etc.
injection mould design is reasonable or not will directly affect the plastic shrinkage rate, due to the mold cavity dimension is estimated by the plastic product size and shrinkage rate is obtained, and the shrinkage is or manual of engineering plastics as recommended by the plastic manufacturer of a range of values, it not only with mold gate forms, relates to the gate location and distribution and the crystal orientation of engineering plastics ( Anisotropic) , the shape of the plastic products, injection molding processing plant size, the position and the distance to the gate, and at the same time and mold cooling distribution system is closely related.
influence mainly include thermal shrinkage of plastic shrinkage rate, phase change shrinkage, orientation contraction, compression shrinkage with factors such as elastic recovery, and the influence factors and precision injection parts molding conditions or operating conditions.
speed program control of injection screw injection stroke is divided into 3 ~ 4 stages, in each phase, respectively, using their appropriate injection speed.
for example: in the beginning of the molten plastic through gate to slow down the injection speed, the high-speed injection molding process, slow down at the end of the mold filling, using this method, can prevent the material overflow, eliminate the flow mark, and reduce the residual stress of products, etc.
low-speed mold filling velocity is smooth, product size is stable, less volatile products low internal stress, products inside and outside the converge to stress ( A polycarbonate parts in carbon tetrachloride, for example, using the high-speed injection molding parts have craze to pour injection molding factory, low speed of cracks) 。
under the condition of relatively slow filling mode, the difference in temperature of material flow, especially the gate material before and after the temperature difference is big, helps to avoid the happening of shrinkage cavity and depression, but due to the mold filling time continue to make parts appear layering and the combination of poor weld mark, not only affect the appearance, and make the mechanical strength is reduced greatly.
high speed injection, the material flow speed, when the high-speed molding smoothly, quickly filled with cavity, melting temperature is expected to fall less, less viscosity decreased too, can be used in a lower injection pressure, is a kind of hot material molding, high speed filling mould can improve gloss and smoothness of the parts, eliminate the phenomenon of the seam line and stratification, small shrinkage depression, uniform color, the product can guarantee the most plentiful.
but easy to produce products of fat blister or yellowing of the parts, and even burn zoom, or cause demoulding difficulty, or appear molding uneven phenomenon, for high viscosity plastic could lead to melt fracture, make the surface produces clouds.
here are several aspects for precision injection molding processing mold precision request to give us a detailed answer.
1, precision injection molding processing plants to the request of the scale, this is wonderful, have bigger errors of the scale of the mold, the output by the errors of the scale of the natural goods would exist.
2, roughness of precision injection molding processing factory appearance request, if the appearance of the mould can't smooth and detailed, the output of goods will be relatively coarse, needs polishing again and even scrapped directly, this directly affects the working efficiency of the company.
3, precision injection molding processing factory to the request of the density, under normal circumstances, the higher the density of the mold the confined ability is stronger, injection molding processing factory also is not easy deformation, so tricky to mould density selected also.
plastic mold precision injection molding processing, should be first selected engineering plastic material, and can perform engineering plastics and precision injection must choose those high mechanical properties, dimension stability, creep resistant performance is good, environmental stress cracking resistance of the material.
in the machining process, factors influencing the precision of injection molding products mainly from the temperature of the mold, injection molding process control, and the scene of the production environment temperature and humidity change amplitude and the acquired product annealing treatment, etc.
injection mould design is reasonable or not will directly affect the plastic shrinkage rate, due to the mold cavity dimension is estimated by the plastic product size and shrinkage rate is obtained, and the shrinkage is or manual of engineering plastics as recommended by the plastic manufacturer of a range of values, it not only with mold gate forms, relates to the gate location and distribution and the crystal orientation of engineering plastics ( Anisotropic) , the shape of the plastic products, injection molding processing plant size, the position and the distance to the gate, and at the same time and mold cooling distribution system is closely related.
influence mainly include thermal shrinkage of plastic shrinkage rate, phase change shrinkage, orientation contraction, compression shrinkage with factors such as elastic recovery, and the influence factors and precision injection parts molding conditions or operating conditions.
speed program control of injection screw injection stroke is divided into 3 ~ 4 stages, in each phase, respectively, using their appropriate injection speed.
for example: in the beginning of the molten plastic through gate to slow down the injection speed, the high-speed injection molding process, slow down at the end of the mold filling, using this method, can prevent the material overflow, eliminate the flow mark, and reduce the residual stress of products, etc.
low-speed mold filling velocity is smooth, product size is stable, less volatile products low internal stress, products inside and outside the converge to stress ( A polycarbonate parts in carbon tetrachloride, for example, using the high-speed injection molding parts have craze to pour injection molding factory, low speed of cracks) 。
under the condition of relatively slow filling mode, the difference in temperature of material flow, especially the gate material before and after the temperature difference is big, helps to avoid the happening of shrinkage cavity and depression, but due to the mold filling time continue to make parts appear layering and the combination of poor weld mark, not only affect the appearance, and make the mechanical strength is reduced greatly.
high speed injection, the material flow speed, when the high-speed molding smoothly, quickly filled with cavity, melting temperature is expected to fall less, less viscosity decreased too, can be used in a lower injection pressure, is a kind of hot material molding, high speed filling mould can improve gloss and smoothness of the parts, eliminate the phenomenon of the seam line and stratification, small shrinkage depression, uniform color, the product can guarantee the most plentiful.
but easy to produce products of fat blister or yellowing of the parts, and even burn zoom, or cause demoulding difficulty, or appear molding uneven phenomenon, for high viscosity plastic could lead to melt fracture, make the surface produces clouds.
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