Shrinkage phenomenon:
1. Vulcanization temperature is too high;
2. Excessive rubber material;
3. Vulcanization speed is too fast;
4. Open overflow trough is not;
5. Mold problems lack of material.
Cause:
1. The air between the mold and the rubber cannot be discharged.
2. Weighing is not enough.
3. Insufficient pressure.
4. The fluidity of the rubber is too bad.
5. Mold temperature is too high and the material scorches.
6. The material was scorched early (dead material).
7. The material is not thick enough and the flow is not sufficient.
Solution:
1. Open the exhaust slot.
2. Multiple exhausts.
3. Increase the pressure
4. Change the formula and increase the fluidity of the rubber.
5. Change the recipe to prolong the scorch time
6. Increase the material thickness.
Spraying, Whitening
Reasons:
1. Insufficient vulcanization.
2. Excessive amount of compounding agent, exceeding the solubility of rubber.
Solution:
1. When prolonging sulfur or taking secondary vulcanization
2. Adjust formula to reduce the amount of low solubility compounding agent
Bubbles, Porose
Reasons:
1. Insufficient vulcanization.
2. Insufficient pressure.
3. There are impurities or oil in the mold or in the rubber compound.
4. The curing temperature is too high.
5. Less vulcanizing agent and slow curing rate.
Solution:
1. Pressurize
2. prolonging sulfur time
3. Adjust the recipe to speed up the cure.
4. More exhaust.
5. The mold temperature cannot be too high.
6. Increase the amount of vulcanizing agent.
Cracking
Causes:
1. The vulcanization rate is too fast and the glue flow is insufficient.
2. Dirty mold or glue stains.
3. Too much release agent or release agent
4. The thickness of the rubber material is not enough.
Solution:
1. Reduce the mold temperature, slow down the cure rate.
2. Keep the compound. Mold cleaning.
3. Use less release agent or release agent.
4. The rubber material is thick enough.
Cracking of the product
Causes:
1. The mold temperature is too high or the sulfur is too long.
2. Excessive amount of curing agent.
3. The demoulding method is wrong.
Remedy:
1. Reduce the mold temperature.
2. When shortening sulfur.
3. Reduce the amount of curing agent.
4. Spray release agent.
5. Take the correct mold release method.
The Difficult to Process
Reasons:
1. Product tear strength is too good, (such as high tensile adhesive). This kind of difficult processing shows that the flash can't tear. 2. The product is poor in strength. It is characterized by a brittle edge and tears together the product.
Remedy:
1. If it cannot be torn off, you must adjust the formula and fill with more compounding agent to reduce shrinkage.
2. If it is torn, reduce the mold temperature and shorten the sulfur.
3. Reduce the amount of vulcanizing agent.
4. Adjust formula to increase rubber strength.
