Firstly, there are generally several reasons for screw fracture:
1. The problem with the design of the screw itself. For example, the size of the screw design is too small and the diameter is not thick enough.
2. Cold start temperature is low.
3. All the components of the entire screw are not in one center, not on a single dot.
4. The startup speed is set too fast.
5. Foreign objects, such as iron blocks, screws, etc., are stuck in the material barrel and may break due to high pressure during glue melting.
6. The raw material temperature is too low.
7. Materials containing metallic substances.
8. Adjust the pressure and speed based on the material model.
9. The screw and oil motor are not assembled accurately.
10. The screw itself has poor quality, so it is to choose DEMAJI screws that use high-quality raw materials.
11. The operator violated the operating procedures. There are mainly two aspects, having worked on high-temperature materials such as PC, PMMA, PA, PET, PBT, etc., it is necessary to use cleaning materials to clean the screw and barrel. No cleaning was done during the material change operation. Secondly, without checking whether the temperature is sufficient (sometimes the heater on a certain section of the barrel suddenly breaks down, and the thermocouple breaks down), remember: different materials need to use different screws. Using ordinary screws to brew PC and other materials with low fluidity and high viscosity is prone to screw breakage.
Secondly, the reason for the broken check ring:
Generally, it is used for engineering plastics such as PA+fiber wear, which is related to the material. During production, whether it increases the amount of glue melted or not is usually due to the breakage of the check ring. Normal rupture of the check ring is accompanied by severe adhesive return, abnormal glue melting and injection, a thin check ring, and insufficient exhaust of raw materials.
Thirdly, an analysis of the causes of glue leakage in injection molding machines:
1. The injection molding machine nozzle flange and the injection molding machine barrel are not fixed properly.
2. The contact surface between the flange and the nozzle is worn.
3. If it is a new flange, it may not be tightly fastened to the machine.
4. Is there any swinging of the injection table during glue spraying and melting
Fourth: Reasons for screw glue return:
1. Barrel wear.
2. Wear of screw scales.

Fifth: The screw spline cannot fit into the oil cylinder, causing the screw head of the injection molding machine to break:
1. The angle of the adhesive head does not match the angle of the flange.
2. The screw length is too long, causing collision between the adhesive head and the flange.
3. If it is a head fracture, it may be caused by the impact of the screw being too long.
4. If it is a central fracture, it must be stuck by glue.
5. At the bottom, it indicates that the precision of the screw head design is insufficient.
Sixth: Analysis and handling methods for abnormal black spots and yellow spots in injection molded products

Abnormal analysis:
1. There is coke on the surface of the nitrogen fluorine dragon screw.
2. The screw barrel and auxiliary equipment (suction machine) of the injection molding machine are not clean.
3. Unclean or corroded check rings, thrust rings, screw heads, front material barrels, etc.
4. There is burnt material on the flange and nozzle.
5. The temperature is too high and the back pressure of the adhesive is too high.
6. The raw materials are unclean.
7. The screw finish of the injection molding machine is insufficient.
8. The material of the nitrogen fluorine dragon screw itself is problematic, and the steel has impurities.

Solution:
1. Check the nitrogen fluorine dragon screw, clean and polish the screw.
2. Check for dust in the hopper, polish the material cylinder, and clean the auxiliary machine.
3. Check for cleanliness or corrosion, clean, polish, or replace.
4. Check the flange and nozzle, clean, polish, or replace them.
5. Check the temperature settings of each section, cool down, and reduce back pressure.
6. Check for impurities in the raw materials and replace them.
Seventh: Analysis of the reasons and solutions for the phenomenon of nonfeeding in the injection system of injection molding machines
There are many reasons for the phenomenon of injection molding machines not eating materials. Based on one's own industry experience, the important reasons can be summarized as follows:
1. Check if the cooling water at the inlet is unobstructed and appropriately reduce the temperature at the inlet.
2. The plasticizing pressure and speed should not be set too high, and the screw speed should not be too fast, especially when producing small products.
4. The design problem of screws is that different materials require different screws after modification. Ordinary screws are not omnipotent.
3. The back pressure valve is damaged or the back pressure is too high.
5. The temperature at the screw discharge port is too high.
6. Is the discharge port unobstructed
7. Is the data of the pressure valve and pressure gauge too high.
8. Is the temperature of the temperature probe hole accurate.
9. The screw is severely worn.
10. There is no material in the hopper.

Solution:
1. Adjust the valve and check if there is any change in the gauge. Repair the back pressure valve or lower the back pressure.
2. Check if there are any sticking blocks at the feeding port, remove the sticking blocks, and increase and unclog the cooling water volume.
3. Check the hopper and feeder to replenish the raw materials.
4. Check the screw barrel and replace it.