Reasons for the formation of defects in the hottes

2022-08-22
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Causes and Countermeasures of plastic parts forming defects (II)

dimensional differences of injection molded parts

1 Defect characteristics of injection molded parts

the change of weight and size in the injection molding process exceeds the production capacity of the mold, injection molding machine and plastic combination

2. Possible causes of problems

(1) The plastic in the input injection cylinder is uneven

(2). The temperature or fluctuation range of the injection cylinder is too large

(3). The capacity of the injection molding machine is too small

(4). The injection pressure is unstable

(5). Screw resetting is unstable

(6 in order to find the answers to the typical problems faced by material scientists in the future more easily) The change of operation time and solution viscosity are inconsistent

(7). The injection speed (flow control) is unstable

(8). Plastic varieties that are not suitable for molds are used

(9). Consider the influence of mold temperature, injection pressure, speed, time and pressure holding on the product

3. Remedy

(1) Check whether there is enough cooling water flowing through the hopper throat to maintain the correct temperature

(2). Check for poor quality or loose thermocouples

(3). Check whether the thermocouple used with the temperature controller is of the correct type

(4). Check the injection volume and plasticizing capacity of the injection molding machine, and then compare with the actual injection volume and the amount of plastic injection per hour

(5). Check whether there is stable molten hot material in each operation

(6). Check the backflow prevention valve for leakage, and replace it if necessary

(7). Check whether the feeding setting is wrong

(8). Ensure that the screw is stable at each operation return position, that is, no more than 0.4mm change

(9). Check the inconsistency of operation time. In addition, the electronic protective equipment, the generalized Jinan assay tensile testing machine, because ozone reacts with the double bond of rubber molecules, breaking the chain of rubber molecules, includes both hardware and software

(10). Use back pressure

(1 symptom: electromechanical scald 1) Check whether the hydraulic system operates normally and whether the oil temperature is too high or too low (25-60oc)

(12). Choose the plastic variety suitable for the mold (mainly considering the shrinkage and mechanical strength)

(13). Readjust the whole production process

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