1. When the product is just started, the cause and solution of the product lack of glue after a period of production

When the injection molding machine material tube melts due to long heating time, low glue viscosity, good fluidity, the product is easy to run, after a period of production due to the melting glue continues to take away the heat, resulting in insufficient glue, large viscosity, poor fluidity, so that the product lacks glue. After production for a period of time, gradually increase the temperature of the material pipe to solve the problem.

2. In the production process, the product lacks glue, and sometimes increasing the injection pressure and speed are ineffective, why?

After production for a period of time, due to the melting glue continues to take away the heat, resulting in insufficient melting glue, large viscosity, poor fluidity, so that the product is short of glue. Increase the temperature of the material pipe to solve.

3. Cause and solution of product ellipse

Product ellipse is due to uneven injection of glue, resulting in uneven pressure around the product, so that the product ellipse, the use of three-point injection, so that the product into the glue uniform.

4. Requirements of precision products for molds

The mold material is required to have good rigidity, small elastic deformation and small thermal expansion coefficient.

5. Purpose of acid resistance test

The product acid resistance test is to detect the internal stress of the product and the position of the internal stress point in order to eliminate the internal stress of the product.

6. Reasons and solutions for metal inserts in the product to crack easily under stress

Insert in the product, due to the teary-eye melt meets the cold insert during injection molding, internal stress will be formed, making the strength of the product decrease and easy to crack. During production, inserts are preheated.

7. Rationality and selection method of mold exhaust point

The mold exhaust point is not reasonable, not only can not exhaust effect, but will cause product deformation or size change, so the mold exhaust point should be reasonable. To select the exhaust point of the mold, the exhaust should be opened in the place where the product is full of glue and the place where the product is trapped and burned.

8. Causes and solutions of brittle cracking of products

The product is easy to crack because the product uses too much water and secondary materials to cause the product to crack easily, or the material stays in the material tube for too long, resulting in the aging of the rubber material, making the product easy to crack. Increase the proportion of new material, reduce the number of times of recycling of water inlet material, generally not more than three times, to avoid the rubber material in the material tube for a long time.

9. Reasons and solutions for the occurrence of flash fiber in glass fiber products

It is due to the low melting temperature or mold temperature, the injection pressure is insufficient, resulting in the glass fiber in the glue can not be well combined with the plastic, so that the flood fiber appears. Increase the melt temperature, mold temperature, increase the injection pressure.

10. The influence of feed port temperature on the product If the feed port temperature is too high or too low, it will cause the machine to return the material unstable, make the feeding amount unstable, and affect the size and appearance of the product.

11. Causes and solutions of transparent products with white spots

Transparent products have white spots caused by cold glue entering the product, or dust inside the material. Increase the nozzle temperature, add cold feed well, keep raw materials to prevent dust from entering.

12. What is the injection molding machine injection capacity?

Injection capacity PW= discharge pressure (kg/cm2) × discharge volume (cm3) /1000

13. What is the injection horsepower of the injection molding machine?

Injection horsepower PW (KW) = injection pressure (kg/cm2) × injection rate (cm3/sec) ×9.8×100%

14. What is the injection molding machine injection rate?

Exit rate V (cc/sec) = density /4×d2×rd2: tube diameter r: density of material

15. What is the thrust of injection molding machine?

Propellant thrust F (kgf) = L /4 (D12-D22) ×P×2D1: inner diameter of the cylinder D2: outer diameter of the piston rod P: system pressure

16. What is the injection molding machine injection pressure?

Glue pressure P (kg/cm2) =[L /4× (D12-D22) ×P×2]/ (L /4×d2)

17. What is the plasticizing capacity of the injection molding machine?

Plasticizing capacity W (g/sec) =2.5×(d/2.54)2×(h/2.54)×N×S×1000/3600/2h= screw front tooth depth (cm) S= raw material density

18. What is system stress? What is the difference with injection molding pressure?

System pressure (kg/cm2) = the highest working pressure set in the oil pressure circuit, injection pressure refers to the actual pressure of the injection molding machine, the two are not equal.

19. Injection molding machine hydraulic oil requirements:

(1) Appropriate viscosity and good viscosity performance

(2) Good lubricity and rust resistance

(3) Good chemical stability, not easy to gasify into gum

(4) Good foam

(5) The corrosion of parts and sealing devices should be small

(6) The ignition point (flash point) is required, and the freezing point is low.

20. The influence of hydraulic oil viscosity on injection molding machine

When the working temperature of the system is high, the oil with higher viscosity should be used, on the contrary, the oil with lower viscosity should be used. When the working pressure of the system is high, the higher viscosity should be used, because at high pressure, the sealing is more difficult, and the leakage is the main problem. On the contrary, the working pressure of the system is low, it is appropriate to use less viscosity oil, when the working parts of the hydraulic system are running at a high speed, the flow rate of the oil is also high, then the pressure loss will increase, and the leakage is relatively reduced, it is appropriate to use lower viscosity oil, on the contrary, when the working parts are moving at a low speed, it is appropriate to use higher viscosity oil.

21. Loose setting

Correct position of release = moving position of rubber ring + offside distance of screw.

22. The importance of setting the retreat position

If the setting of the release position is too large, it will cause the oxygen absorption of the refeed, which will oxidize the rubber and produce bubbles. The setting of the position is too small, so that the pressure in the cylinder is large, the shear force is too high, so that the rubber material is decomposed, and the nozzle is salivating. The position error cannot exceed 0.4mm.

23. Setting of glue position

Glue position = Weight of product/(maximum stroke/maximum amount of glue)

24. Main Advantages of Gas-assisted injection molding (GAM)

The core of thick material can be evacuated to make hollow pipe fittings, which can save materials and shorten cycle time; The use of gas in injection molding can make the pressure evenly distributed, and when the plastic is cooled and cured, the gas can compensate for the volume contraction of the plastic by expanding; Reduce the internal stress of molded products, thereby improving shape stability and eliminating deformation and warping.

25. The piston rod outer diameter is small in the middle, and the two ends are big problems

Due to the unbalanced shrinkage of the overheating product of the medium hole needle, the outside diameter of the piston rod is small in the middle, and the two ends are large. The medium hole needle cocoa is made of phosphor copper material with fast heat dissipation, and the mold is vented in the middle part of the product.

26. The problem of cracking after screen printing

Due to the stress on the surface of the product, it causes cracking after screen printing. Increase the mold temperature, reduce the stress, the stress can be eliminated by annealing method.

27. Easy breakage of eyeglass frame water edge

The residual internal stress at the edge of the nozzle causes the product to break easily. To solve the problem, reduce the injection pressure and pressure holding pressure as much as possible, and appropriately increase the mold temperature.

28. It is easy to crack when the four pillars of the electrical shell are screwed

Due to the existence of waterline in the column, the product assembly column is prone to burst cracking. The mold increases the exhaust gas, appropriately increases the die temperature, and speeds up the shooting speed to reduce water waterline.

29. Product deformation problem

Product deformation is mainly caused by the imbalance of the product during thermal shrinkage, or due to the product itself under the action of internal stress.

30. Transparent PC shell bubble problem

The raw material is not dry enough, the product has uneven adhesive thickness, the mold exhaust is poor, and the raw material is easy to decompose may cause the product bubbles. Fully dry, increase mold exhaust, and minimize the uneven thickness of the glue.