Bolt Heaters Help Attach Platens To Injection Molding Machine


An original equipment manufacturer needs to heat bolts used to hold platens in their injection molding machines. To effect proper tension, the 6-foot by 3-inch (182 by 7.6 cm) bolt and nut have to be very tight.


The manufacturer packages Watlow FIREROD® bolt heaters with each injection molding machine sold. Correct torque is achieved by sliding the heater through the middle of the bolt and heating it to 200°F (95°C). This elongates the bolt by as much as 0.5 inch (12.5 mm). When the nut is turned tight and the heater removed, the bolt cools and shrinks, tightening even further.

Customers now benefit during initial set up, as well as, reassembling when molds are changed out at the completion of a production run. The OEM credits the Watlow FIREROD bolt heaters with the increase in equipment sales.