Methods for testing whether the injection molding machine screw has countercurrent (for reference)
1. Operation preparation: Set the barrel material temperature to the forming temperature of PP material, prepare the blind hole flange (if not, fill a beer product without opening the mold to wait for complete cooling), and prepare the PP material (water outlet).
2. Set the injection pressure of of injection molding machine to 40%, the firing rate is set to 10%, the back pressure is set to the minimum, the metering setting is the same as the screw diameter (if the screw diameter is 50mm, the metering setting is set to 50mm), the filling time is set to 5 seconds, and the switching position is set to 0.
3. Operation: Use PP material melt glue to extrude three times in a row and then melt the glue, then enter the gun to death, manually shoot the glue until it is completed in 5 seconds, record the injection end point margin position, and then continue to shoot the melt glue in the same method, do it three times and record the injection end point margin position three times. After completing the 5-second injection time, exit the cannon barrel, extrude the glue in screw , remel the glue and then enter the cannon top and die again, change the injection time to 10 seconds, and other parameters remain unchanged. Follow the above operation three times and record the position of the injection termination allowance for each time. (Please note that there should be no glue leakage during the above injection operation, otherwise the result will be inaccurate)
4. Results determination: Use (average value of the margin position of the injection in 5 seconds - average value of the margin position of the injection in 10 seconds) /5= value is less than 0.5mm/s, the screw is suitable for beer plastic and has high molding stability.
If the value is between 0.5mm/s-1.5mm/s, use ABS material to do it again according to the operation of PP material (when using ABS material, remember to set the barrel temperature to the molding temperature of ABS material). If the value produced by ABS material is less than 0.5mm/s, then. The screw has a certain reflux and is only suitable for some beer materials, such as PC, PMMA, PS, POM, PC/ABS and other materials. If the value is greater than 0.5mm/s, it can be judged that the sealing ring is no longer available and needs to be replaced. Of course, the inner wall of the barrel may also be worn, and the screw may be worn to cause reflow. In short, it needs to be repaired or replaced.
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