FACTS Tech Blog

Increase the temperature by 20 to 40 degrees F when the rolls are stopped to maintain a more uniform roll surface temperature.

The TCU (Temperature Control Unit) controls the temperature of the water exiting the calender not the roll surface temperature. This is an important distinction. When the calender is not actively processing rubber, i.e. during warm-up and when the calender is stopped, the roll surface is losing heat to the ambient and thus the TCU is actively heating the water loop. In this condition the roll surface temperature is between 10 degrees to 20 degrees F below the water temperature. Read more…

Keep the calender running – stops cause the rolls to become egg shaped and introduce significant gauge thickness variation.

When the calender is stopped, roll heat loss is not uniform around the roll. Heat loss along the circumference near adjacent rolls is minimal while heat loss in other areas is much higher. This leads to different temperatures and therefore different degrees of roll expansion. A few degrees on a 24” to 30” diameter will result in measurable “out-of-roundness” of each roll. This is true when the calender is empty but even more so when there is a hot bank of rubber between the rolls. The longer the calender is stopped the worse the condition. Read more…