1. If the heating temperature is too high and exceeds the glass softening point, the glass will be easily deformed and its surface quality will be seriously affected.

2. When the radiation temperature of the heating element is too high, the maximum radiation intensity shifts toward shortwave and the radiation heat will pass through the glass and the heat can not be absorbed. As the increase in heat is wasted, it will raise the energy consumption of the glass tempering furnace.

3. If the heating temperature is too low and the temperature gradient is small, the rate of stress relaxation in the glass is reduced. Because of that, the interlayer of the glass cannot be uniformly heated in the same time and its residual stress cannot be completely relaxed. It will affect the redistribution of the stress when the glass is cooled, causing the heated glass to shatter easily in the process of quenching.

4. When the heating temperature is too low, it will also lead to poor tempering performance with fragments not meeting the standard, resulting in fragments of the shattered glass being too large.

So, it is important to set the appropriate heating profile in the heating process of glass tempering. The heating temperature can not be too high or too low. The heating temperature should be set in accordance with the heating characteristics of the glass at different heating periods.