The main purpose is to keep a constant temperature distribution on contact surfaces of plastic raw material in the moulds. After getting the plastic parts from mould, a homogenous temperature distribution must be achieved on the part.  In other words; as we keep the mould under a constant temperature, production will be in ideal condition.

 

Otherwise, there may be some defects such as small shrinkages, flow marks, fluctuations, stress in the materials… etc on the parts. If you see these kind of defects, it is coming from a non-homogeneous distribution of the temperatures. 

 

To achieve a homogeneous temperature distribution, we must design a water cooling system by using pipes, quick release couplings, connecting systems and parts such as seperators, hoses, elbows, plugs.

 

At this moment, the correct selection of these auxiliary parts are very important. Flow rates must be considered. Any restriction in the cooling lines causes low flow rates and decrease in efficiency of production. 

 

The design temperature on the surfaces of moulds must be followed up during production period very closely. It must be under control all the time. Otherwise, if the cooling time is extended, then production time will increase in parallel.

 

The steps of cycle time of production can be explained as below;

1) The closing time of mould of mould for a new part production. This period is directly related with the size of moulds, travel distance, and shape of the part. This is about 5% of total cycle time. 

 

2) Injection period of plastic material into the mould. This is directly related with structure of the part, weight, and viscosity of melted material. The cooling time is defined by the distance of channels to the surface, number of elbows, flow rates. This is about 60% of total cycle time.

 

3) Cooling period of part in the mould is directly related with steel type, design of cooling system, temperature of cooling water at inlet, flow rate, and surface roughness of the cooling channels. This is about 15% of total cycle time. 

 

4) Opening time of mould is directly related of  the size of mould, travel distance, and structure of the part. This is about 15% of total cycle time.

 

5) Parts ejection period is related with the automation level of the system. It can be Manuel, 

 

half-automated or full automated. We can consider this period as 15% of total cycle time..