07-10
Gas assisted injection molding is a special injection molding technology developed on the basis of traditional thermoplastic injection molding technology, which is suitable for special performance req...
The Cooling System is connected with the external water source and forms one or more water circuits in the mold as required. Its role is to pass coolant into the water channel and make it constantly circulate and flow, thereby bringing excess heat in the mold to the outside world.
Whether the mold temperature is reasonable directly affects the dimensional precision and appearance quality of plastic parts. Therefore, the Cooling System is an important work in the mold design. Cooling System generally uses water for cooling, which is due to the large heat capacity of water and low cost.
After the plastic is filled with the cavity, it should be shaped by cooling, so as to obtain a stable quality plastic part. Therefore, the injection mold needs to set a Cooling System to make the mold temperature meet the requirements of the injection process. The mold temperature control system directly affects the quality, forming and production efficiency of the product.
The role of mold temperature control system:
Improve molding performance and shorten the molding cycle.
Stabilize the dimensional precision of the product and prevent deformation.
Eliminate appearance defects and improve the surface quality of plastic parts.
Improve the mechanical properties and physical properties of plastic parts.
In order to improve the efficiency of the Cooling System and make the temperature distribution of the cavity surface uniform, the following principles should be followed in the design of the Cooling System:
1. In the mold design, priority should be given to the cooling method and the location of the cooling circuit.
2. Set up as many cooling water holes as possible.
3. It should be avoided that the cooling pipe is set in the part of the product welding, otherwise when the temperature drops, the welding mark will be more serious, and the welding strength of the plastic parts will be lower.
4. Consider the temperature difference between entrance and exit and reduce the temperature difference.
5. The cooling circuit of the cavity and core should be separated.
1. The common mold can use fast cooling method to obtain a shorter forming cycle, and the precise mold can use slow cooling method and set the mold temperature gauge.
2. If the cooling effect is poor and limited by the structure shape, in order to improve the cooling effect, consider choosing materials with good thermal conductivity, such as wrinkle copper and copper alloy.
3. When the mold only have one entrance and exit, the cooling pipe should be connected in series.
4. In order to facilitate repair when blocked, the cooling design of the seal ring should be used less.
5. When the plastic with large shrinkage is used, the cooling pipe should be set along the shrinkage direction so that the plastic part does not deformation.
Use mold materials with high thermal conductivity
The cooling effect of copper and alloy copper materials is good.
Indirect cooling for small core
It is often impossible to set a cooling circuit directly in the core, and if no special cooling method is used, the cooling efficiency of the core will be reduced.
Catridge Heater replace Copper Rods for heat conduction
In order to improve the cooling effect, catridge heater have been used to replace copper rods for heat conduction in recent ten years, and obvious economic benefits have been achieved. Catridge heater is an excellent heat conduction element, and its thermal conductivity is about 1000 times than that of the same size copper rod.
Apply rapid cooling line
Its advantages are :
Speed up the molding cycle.
Cooling circuit is simple.
Reduce maintenance.
Uniform product quality.
Improve appearance and dimensional precision.
