1. When the product first started up, there was a sharp edge (flying edge), and the reason and solution for the lack of glue in the product after a period of production.

When the injection molding machine is first turned on, the melt in the material tube has a long heating time, low viscosity, good fluidity, and the product is prone to peeling. After a period of production, the heat is continuously carried away by the melt, resulting in insufficient melt, high viscosity, and poor fluidity, resulting in a shortage of glue in the product. After a period of production, gradually increase the temperature of the material pipe to solve the problem.

During the production process, the product lacks glue, and sometimes increasing the injection pressure and speed is ineffective. Why?

After a period of production, due to the continuous heat carried away by the adhesive, the adhesive is insufficient, with high viscosity and poor fluidity, resulting in a shortage of adhesive in the product. Raise the temperature of the material pipe to solve the problem.

3. Reasons and solutions for product ovality.

The elliptical shape of the product is caused by uneven pressure around the product due to uneven gluing. Three point gluing is used to ensure even gluing of the product.

4. Requirements for precision products on molds.

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

5. Purpose of product acid resistance test.

The acid resistance test of a product 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 products that are prone to cracking under stress.

When placing inserts in the product, during injection molding, due to the hot tears in the eyes and the molten adhesive encountering cold inserts, internal stress will be formed, resulting in a decrease in product strength and susceptibility to cracking. During production, preheat the inserts.

7. Rationality and selection method of mold exhaust points.

The unreasonable exhaust point of the mold not only fails to achieve the exhaust effect, but also causes product deformation or dimensional changes, so the exhaust point of the mold should be reasonable. When selecting the mold exhaust point, the exhaust should be opened in the area where the product is filled with glue at the end and where the product is trapped and burned.

8. Reasons and solutions for product brittleness and cracking.

The product is prone to brittle cracking due to the use of too many nozzle materials and secondary materials, or if the material stays in the material tube for too long, causing aging of the rubber material and making the product prone to brittle cracking. Increase the proportion of new materials and reduce the number of times the nozzle material is recycled. Generally, it should not exceed three times to avoid the rubber material staying in the material pipe for a long time.

9. Reasons and solutions for the tendency of fiberglass products to become prone to fiber spreading.

It is due to the low melting temperature or mold temperature, insufficient injection pressure, which causes the glass fiber to not bond well with the plastic inside the adhesive, resulting in the occurrence of fiber flooding. Increase the melt temperature, mold temperature, and injection pressure.

10. The impact of inlet temperature on the product.

If the temperature of the feed inlet is too high or too low, it will cause unstable machine feeding, unstable feeding amount, and affect the size and appearance of the product.

11. Reasons and solutions for white spots in transparent products.

Transparent products may have white spots due to cold glue entering the product or dust inside the material. Raise the temperature of the nozzle, cool the material well, and store the raw materials carefully to prevent dust from entering.

12. What is the injection capacity of an injection molding machine.

Ejection ability PW=Ejection pressure (kg/cm2) × Ejection volume (cm3)/1000

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

Ejection horsepower PW (KW)=Ejection pressure (kg/cm2) × Ejection rate (cm3/sec) × nine point eight × 100%

14. What is the injection rate of an injection molding machine?

Ejection rate V (cc/sec)= л/ four × D2 × Rd2: diameter of the material tube r: density of the material

15. What is the injection thrust of an injection molding machine?

Ejection thrust F (kgf)= л/ 4 (D12-D22) × P × 2D1: Inner diameter of oil cylinder D2: Outer diameter of piston rod P: System pressure

16. What is the injection pressure of an injection molding machine?

Injection pressure P (kg/cm2)=[ л/ four × (D12-D22) × P × 2]/（ л/ four × D2)

17. What is the plasticizing ability of an injection molding machine?

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

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

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

19. Requirements for hydraulic oil used in injection molding machines:

(1) Appropriate viscosity and good viscosity performance

(2) Good lubrication and rust resistance

(3) Good chemical stability, not easily vaporized into colloid

(4) Foam is good

(5) The corrosion to the components and sealing devices should be minimal

(6) The ignition point (flash point) requirement is to have a low freezing point.

20. How does hydraulic oil viscosity affect injection molding machines?

When the working environment temperature of the system is high, higher viscosity oil should be used. Conversely, lower viscosity oil should be used. When the working pressure of the system is high, higher viscosity oil should be used because under high pressure, sealing is difficult, and leakage is the main problem;

On the contrary, when the working pressure of the system is low, oil with lower viscosity should be used. When the operating speed of the hydraulic system's working components is high, the flow rate of the oil is also high, and the pressure loss will increase, while the leakage amount is relatively reduced. Therefore, oil with lower viscosity should be used. On the contrary, when the operating speed of the working components is low, oil with higher viscosity should be used.

21. Setting of release.

The correct position for loosening=the position for moving through the rubber ring+the offset distance of the screw.

22. Importance of Setting the Release Position

If the loosening position is set too large, it will cause oxygen absorption in the return material, causing the rubber to oxidize and produce bubbles. If the position is set too small, the pressure inside the material barrel will be high, and if the shear force is too high, the rubber material will decompose and the nozzle will salivate. The position error cannot exceed 0.4mm.

23. Setting of Melting Adhesive Position

Melting position=weight of the product/(maximum stroke/maximum melting amount)

24. Main advantages of gas assisted injection molding (GAM)

It can empty the thick material core and make hollow pipe fittings, which can save materials and shorten the cycle time.

The use of gas in injection molding can evenly distribute pressure, and as the plastic cools and solidifies, the gas can compensate for the volume shrinkage of the plastic through expansion.

Reduce internal stress in molded products, thereby improving appearance stability and eliminating deformation and warping.

25. Is the outer diameter of the piston rod small in the middle and large at both ends?

Due to the overheating of the middle hole needle and uneven shrinkage of the product, the outer diameter of the piston rod is small in the middle and large at both ends. The middle hole needle is made of phosphorous copper material with fast heat dissipation, and the mold exhausts air in the middle part of the product.

26. Cracking problem after spherical screen printing

Due to the presence of stress on the surface of the product, it causes cracking after screen printing. Increasing mold temperature and reducing stress can be achieved by annealing to eliminate stress.

27. The problem of easy breakage at the water edge of the eyeglass frame

The residual internal stress at the water outlet due to high injection pressure and holding pressure can cause the product to break easily. Try to reduce the injection pressure and holding pressure as much as possible, and increase the mold temperature appropriately to solve the problem.

28. The problem of easy cracking when screwing the four pillars of the electrical casing

Due to the presence of water lines in the columns, the product assembly columns are prone to cracking. The mold should increase exhaust, increase the mold temperature appropriately, and accelerate the injection speed to reduce water lines.

29. Product deformation issues

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

30. Bubble problem with transparent PC casing

Insufficient drying of raw materials, uneven adhesive thickness in the product, poor mold exhaust, and easy decomposition of raw materials may all cause product bubbles. Fully dry, increase mold exhaust, and minimize uneven adhesive thickness.