1. Under premise of ensuring sufficient mechanical strength of steel material, water transport should be arranged as close to surface of cavity (core) as possible. And distance from each other to cavity should be as equal as possible to enhance cooling and make mold temperature uniform.
2. Under premise of ensuring sufficient mechanical strength of steel, water transportation should be arranged as close as possible.
3. Water transportation diameter is preferably 10mm, and diameter of each water channel should be same as possible.
4. Large molds can divide water transport into several independent circuits to increase flow of coolant, reduce pressure loss and improve heat transfer efficiency. Because water transport is too long, it will cause a large temperature gradient change, resulting in a higher temperature at end of water transport, thereby affecting cooling effect.
5. Thick parts of product wall should be specially cooled. Or use strengthening measures at thin wall to make mold temperature uniform.

 

6. Fully consider thermal conductivity of mold material, beryllium copper inserts can be used to dissipate heat in areas where water cannot be transported and cooling must be enhanced.
7. Water transport inlet should be close to gate, because temperature near gate is high, cooling should be strengthened.
8. When one mold has multiple cavities, try to separately design water transportation in each cavity for easy control.
9. Water transportation arrangement should be as consistent as possible with product shape.
10. Larger sliders and oblique squares also need to be equipped with water transportation. Because of their large size, lack of cooling will affect quality of molded products.
11. Install heat pipes or molds with high mold temperature. According to situation, nozzles and guide posts are equipped with water to enhance cooling to prevent them from being burned by high temperature and biting during movement.
12. When pipe joint and throat plug are in same direction, the nearest distance between center is not less than 25MM, distance between water transportation margin and product level margin is generally not less than 10MM, design is between 10MM-12MM as much as possible; alloy mold is generally 25MM.
Problem that should be paid attention to when determining diameter of cooling water hole is that no matter how big mold is, diameter of water hole cannot be greater than 14mm, otherwise it is difficult for cooling to form a turbulent flow.
Generally, diameter of water hole can be determined according to average meat thickness of product. When average thickness is less than 2mm, diameter of water hole is 8~10mm; when average thickness is 2~4mm, diameter of water hole is 10~12mm; when average thickness is 4~6mm, diameter of water hole is 10~ 14mm. Walls of plastic parts of mobile phones are mostly very thin, diameter of water hole is 8mm. When finished product is small, it can also be 4mm.

 

1. Cooling water to glue position should be as equal as possible, distance between 10-15mm is more appropriate, and center distance of cooling water is about 3D-5D.
2. Water hole should not be near place where glue is finally welded.
3. Water pipe should avoid interference with other mechanisms on mold (such as: thimble, cylinder, inclined top, Boss column, small insert, guide column, guide sleeve, back needle, side core pulling, fixed distance parting mechanism) , keep steel position 5mm in the middle.
4. Points to note when designing cooling system:
A. Avoid getting close to parts where product is prone to welding marks to prevent weak welding and reduce product strength.
B. Water transportation should not have too long dead angle, so as not to affect effect of cooling water backflow.
C. "O" ring should be one size larger than diameter of water hole. For example, common Φ10 waterway is selected as P12 "O" ring, outer diameter of installation groove is 1mm larger than O ring, and "O" ring is installed on mold plate.
5. Water transport, air cap, and oil pressure circuit are not less than 8MM; water transport side and nozzle avoiding side are not less than 8MM; water transport side and inner mold side are not less than 10MM.

1. For plastics with low surface and good fluidity (such as polyethylene PE, polypropylene PP, polystyrene PS, nylon, etc.), mold temperature required by molding process is not too high. Usually, it can be cooled by water at room temperature, mold temperature can be controlled by adjusting water flow. If product productivity is high, cold water can also be used to shorten molding cycle.
2. For plastics with high viscosity and poor fluidity (such as polycarbonate PC, hard polyvinyl chloride PVC, polyphenylene ether PPO, etc., in order to improve performance of die, molding process often requires a higher mold temperature and mold needs to be heated.
3. For plastics with a low viscosity flow temperature or melting point, it is generally necessary to use room temperature water or cold water for cooling. If fluidity of die needs to be improved, or to solve quality problems of some molded products, heating measures can also be used.
4. For viscous flow temperature or high melting point plastics, warm water can be used to control mold temperature, which not only allows warm water to cool plastic products, but is also more conducive to uniform mold temperature distribution than normal temperature water and cold water.
5. For thermosetting plastics, mold temperature requires 150-220, and mold must be heated.
6. Due to geometric shape of product, temperature in mold is not necessarily equal, and uneven temperature distribution often leads to problems in molding quality. For this reason, local heating or local cooling can be used on mold to improve temperature distribution of product.

 

7. For products with a long process and thick walls, or precision products with a large molding area although viscous flow temperature and melting point are not high, to ensure that plastic melt does not flow due to temperature drop during filling process, appropriate heating measures can also be taken to mold.
8. For large injection molds whose working temperature is higher than room temperature, a heating device can be installed to ensure that mold is preheated in a short time before production.
9. In order to accurately adjust and control mold temperature in real time, heating and cooling devices are set if necessary.
10. For small and thin-walled precision products, mold temperature required by molding process is not high, it is not necessary to install a cooling device and directly cool it naturally.
11. Layout of mold cavity try to balance mold temperature and heat preservation. Arrangement of mold cavity not only affects balance of gating system, but also has a greater relationship with thermal balance of mold temperature field. If mold temperature field cannot maintain thermal equilibrium, shrinkage rate of product cannot be uniform and stable. In order to ensure thermal balance of temperature field and logistics balance of gating system, when designing a multi-cavity mold, number of cavities should not exceed 4 as much as possible, and cavity arrangement should be balanced.