Analysis of the reasons for the differences in the thickness of extruded products

Extrusion lamination is getting more and more use and attention because of its environmental performance. The thickness error of the film is one of the important criteria to measure the quality of the product. Therefore, the following process control points should be noted during production to improve thickness uniformity and reduce errors.

The factors that generally cause thickness error are:

1, screw, barrel wear, screw speed instability or pulse resonance.

This situation will cause the molten resin backflow, extrusion volume fluctuations, making part of the molten resin in the flow channel for too long. Therefore, at the set temperature, the molten resin will be thermally decomposed and its physical viscosity will be changed; after leaving the die, it cannot be molded according to the size of the die opening.

2, extruder with thermocouple and compensation line type error, damage, poor installation.

Under the wrong temperature, the molten resin will be thermally decomposed and the physical viscosity will be changed; after leaving the die, it will not be molded according to the die size. Companies should pay attention to the thermocouple and compensation line, the use of only three years.

3, extruder with electric heating sheet, solid state relay type error, damage, poor installation .

This situation will also make the production temperature error, therefore, the electric heating sheet and solid state relay after three years of use, the need to test the performance parameters and dimensions.

4, screw, barrel, runner, mold mouth and other places of molten resin is high temperature sintering carbonization.

If the machine is not started and stopped according to the operating procedures, the molten resin at the mold mouth will be seriously carbonized.

5、Die lip damage, tightening adjustment bolts sintered, can not be adjusted.

The die head needs to be disassembled and cleaned and repaired every year, and the size of the die opening is adjusted and the bad fasteners are replaced.

6、The type parameter of die head fastening adjusting bolt is wrong or damaged, and the installation is bad.

Extruder die head and other high-temperature section, fasteners need to choose performance parameters 12.9 level, to ensure the mechanical properties of fasteners in high temperature. Install the die head fasteners to use special torque plate hand or tighten the fasteners according to the process requirements, fastener loosening to be consistent.

7, extruder screw, runner, die head, filter coupling section design lack of filling.

According to the size of extrusion reasonable design process size, reasonable design of the flow channel, and try to avoid the rupture of the resin melt.

8, PP, PE resin type error or not according to the material process requirements.

9, silicone pressure roller surface defects or poor cooling.

10, extruder screw, a section of wear or foreign objects.

11, extruder screw sections, molten resin state is not good.

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