PC has excellent performance, high transparency, good impact toughness, creep resistance, wide range of temperature. The process characteristics of PC are: the sensitivity of melt viscosity to shear rate is small, but it has great sensitivity to temperature, no obvious melting point, high viscosity of melt, easy hydrolysis of resin at high temperature and easy cracking of products. In view of these characteristics, we should pay special attention to the different treatment: to increase the fluidity of the melt, […]
Under normal circumstances, the surface gloss of injection molded parts is mainly determined by the type of plastic, colorant and surface finish of the mold. But often because of some other reasons, the surface color and luster defects of products, surface dark and other defects. The causes and solutions are as follows:
(1) Poor finish of the mold, rust on the surface of the cavity, poor exhaust of the mold.
(2) The pouring system of the mould is defective, so it […]
The fusion joint melt plastic in the cavity is confluent in multiple strands due to the penetration hole, the flow rate is not consistent, and the area where the filling material flow is interrupted. This kind of fusion of low temperature molten material can not fully fuse and produce linear fusion joint. In addition, the injection filling of the gate will also produce the fusion joint. This kind of weld mark only occurs at the fusion part of […]
Adjust and compare the injection molding process temperature, pressure, speed and position parameters
Temperature measurement and control is very important in injection molding. Although these measurements are relatively simple, most injection molding machines do not have enough temperature sampling points or lines.
On most injection molding machines, the temperature is sensed by thermocouples. A thermocouple is basically made up of two different wire tails. If one end is hotter than the other, a tiny telecommunication will be generated; The more heat, the stronger the signal.
Thermocouples are also widely used as sensors in […]
In the process of plastic production, various reasons lead to different defects of various products. The following are common product defects and solutions:
There are some non design reasons, such as mold temperature, material temperature, high temperature, insufficient holding time and residual stress, etc. when the deformed products are out of the mold. The product wall thickness and uneven shrinkage, improper gate position and ejector position, and mold sticking must be considered in the design.
The vacuum state caused by too […]
What is unstable gauge?
Dimensional instability (unstable gauge) refers to the change in the size of plastic parts between each batch of molded products or between each cavity molded products produced by each mold under the same injection molding machine and molding process conditions. As shown in the figure:
The change of product size is caused by abnormal equipment control, unreasonable injection molding conditions, poor product design and material performance change.
Analysis and elimination of injection defects of unstable gauge
1) Inconsistent conditions […]
The defects and abnormal phenomena of injection molding are finally reflected in the quality of injection molded products. The disadvantages of injection molded products can be divided into the following points:
(1) Insufficient product injection;
(2) Product overflow;
(3) Product dents and bubbles;
(4) The product has contact mark;
(5) The product is brittle;
(6) Plastic discoloration;
(7) The products have silver wire, stripes and flow marks;
(8) The product gate is muddy;
(9) Product warpage and shrinkage;
(10) The product size is not accurate;
(11) Product paste in mold;
Causes and solutions of sprue sticking during injection molding:
(1) The cooling time is too short and the sprue has not yet solidified.
(2) If the gradient of the sprue is not enough, the demoulding gradient should be increased.
(3) The improper fit size between the sprue bushing and the nozzle results in leakage.
(4) The main channel is rough and there is no cooling well in the main channel.
(5) If the temperature of nozzle is too low, the temperature should be increased.
About JasonMould […]
“Product quality is everyone’s responsibility”. High quality products are produced, managed and controlled, not inspected. The goal is excellent quality, customer satisfaction, and one-time molding pass rate of more than 98%. To achieve the above goals, all employees must improve their quality awareness and sense of responsibility, and do a good job according to the following requirements:
1. When the beer is opened, it is necessary to adjust the machine according to the process parameters in the “forming process record”. […]
ABS, commonly known as acrylonitrile butadiene styrene, is made by copolymerization of acrylonitrile butadiene styrene. Due to the different proportions of the three monomers, ABS with different properties and melting temperature can be expanded to ABS with different uses and properties, such as impact grade, heat resistance grade, flame retardant grade, transparent grade, reinforced grade, electroplating grade, etc., if it is blended with other plastics or additives.
The fluidity of ABS is between PS and PC. the fluidity of ABS […]