Mold surface temperature

Tempering - Homogeneous tempering refers to minimization of the mold surface temperature between the inlet and outlet of the cooling fluid. 

Fig. 16.1. Micrographs of injection molded samples in jx)larized light. The distinctive processing conditions are reported in label (PhUd = Packing pressure Tmoid = Mold surface temperature)...

Mold surface Temperature Part quality even cooling prevents distortion... 

S. C. Chen, H. M. Li, S. T. Huang and Y. C. Wang, Effect of decoration film on mold surface temperature during in-mold decoration injection molding process. International Communications in Heat and Mass Transfer, 37, 501-505 (2010). 

Homogeneous tempering refers to minimization of the mold surface temperature difference between the inlet and outlet of the cooling fluid. Wall temperature differences could cause warping of the part. Thermoplastic molds are cooled with water and oil if higher temperatures are required because water tempering equipment is limited to 140°C. 

After completing a production run the mold surfaces should be washed scrupulously with a mild alkaline solution such as sodium nitrate. After drying, the mold surfaces should be sprayed with an oil or silicone base spray. Mold surface temperatures and size of ejectors have a considerable influence on the cycle time with respect to deep draw components, such as computer housings etc.. 

Dynamic Mold Surface Temperature Control for Assisting Injection Molding of Light-Guide Plate and Improving Optical Performance... 

In the present study, we design an optical pattern of PC resin so that the light distribution characteristics within the plate from the side LED source light can be understood in a better manner. Then, molding experiments compare the effect of the replication of conventional injection molding with or without dynamic mold surface temperature control of LGP molding. 

In the (lynamic mold surface temperature control operation process, the mold was preheated to 85 C, and then the mold was opened so the induction coil conld move into the mold. Induction heating was turned on. When mold center reached the taiget temperature of 155 C (measured temperature distributions are shown in figure 7), induction heating was turned off, and the induction coil was moved out of the mold. The mold was closed, and then the conventional injection molding process continued. 

In this study, the dynamic mold surface temperature control is utihzed to achieve a rapid mold surface temperature variation to assist the injection molding of the LGP. When the mold temperature exceeds 140°C for the injection molded parts of the LGP, the dimensional accuracy of the micro-featirre achieved a rating of about 94.66% to 98.22%, so that reasonable accuracy in micro-feature replication can be achieved, residual stress can be reduced and litminance values can be increased by about 33.50% near the light soitrce and 49.40% farther from the hght. 

Position Mold Insert Without Dynamic Mold Surface Temperature Control With Dynamic Mold Surface Temperature Control Improvement (%)... 

Figure 9. Measured temperature variations of core and cavity for dynamic mold surface temperature control. (One heating/cooling cycle)...

Figure 11. Residual stress illumination distribution of LGR (a) with or (b)without dynamic mold surface temperature control.

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