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Twelve principles of screw barrels for injection molding machines

Update:07-01-2020
Summary:

One: The material and the screw must be matched. Especi […]

One: The material and the screw must be matched. Especially for corrosive materials and hard materials, such as PVC, flame retardant materials, glass fiber materials must use professional screws, do not use ordinary screws.

2: If the common machine uses corrosive materials, it must be cleaned and replaced with stable materials such as HDPE, HIPS, etc. as soon as possible after use.

Three: If the ordinary machine occasionally uses glass fiber material, be sure to use high material temperature, low screw speed, low back pressure, keep in mind

Four: When the injection molding machine starts, it should be fully preheated. After the barrel reaches the preset temperature, keep it warm for 15 minutes below Φ60mm. After the above 30 minutes, start the motor to start the screw-related actions.

Five: Regardless of the material, try not to use the lower temperature limit production. For example, the PC material can be produced at 250 degrees, and ABS can be made at 185 degrees, but it is not good for the screw because it requires large torque and serious wear. At the same time, if the lower limit problem must be used, use a low screw speed.

Six: For more than half an hour of shutdown each time, it is best to close the blanking port and clean the material in the barrel, and set the insulation.

Seven: Avoid foreign objects falling into the barrel to damage the screw and barrel. Prevent metal fragments and debris from falling into the hopper. If processing recycled materials, a magnetic hopper must be added to prevent iron filings from entering the barrel.

Eight: When using anti-salin, make sure that the plastic in the barrel is completely melted, so as not to damage the transmission system parts when the screw is retracted.

Nine: Avoid screw idling and slipping.

Ten: When using new plastic, the remaining material of the barrel should be cleaned. When using POM, PVC, PA + GF and other materials, reduce the degradation of raw materials as much as possible. After shutdown, flush with ABS and other nozzle materials in time.

Eleven: Avoid mixing POM and PVC into the barrel at the same time. Reaction will occur at the melting temperature and cause serious industrial accidents.

Twelve: When the temperature of the molten plastic is normal but the black spots or discoloration of the molten plastic are constantly found, check the rubber screw check ring seat (rubber ring, meson) for damage.

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