STS Thermal SystemsSTS Thermal Systems
STS Thermal Systems

Square Cartridge Heaters

Square Cartridge Introduction PDF

Square Cartridge Heater Configurator

Square Cartridge Dimensional and Electrical Specification PDF

The square heater assembly consists of an element wound on shaped ceramic cores and securely connected to internal lead conductors. This assembly is centrally located within shaped tubing and voids are filled with ceramic insulation. The heater assembly is swaged to the final square cross-sectional dimensions to metallurgically bond the element wire to the lead conductors and to compact the internal ceramic core and ceramic insulation to near theoretical density. The densely compacted assembly provides the optimum heat transfer and insulation dielectric essential to heater performance and reliability and maximizes the heaters resistance to vibration, shock and physical abuse.

As an alternative to traditional round cartridges and their costly, time consuming deep hole drilling requirements, square cartridges utilize simple, cost effective surface milled slot mounting systems. This approach provides close fits between the cartridge and tooling maximizing heat transfer and performance while still allowing easy heater removal for maintenance and cleaning. Lead channels added during the slot machining process provide total protection for the heater power leads while allowing routing of the leads to connectors or terminal strips at any desired location on the tool. A square cartridge forming option further simplifies heating of special shapes and can be utilized in heating both large and small tooling components.


Precision plate and component heater assemblies are designed for a wide range of extrusion, molding and packaging applications. The rugged, high performance assemblies provide exceptional performance in the heating of extrusion profile dies, blow-molding manifolds and die heads, wire cross head dies, extruder barrels, polymer pumps, and injection molds.

Square Cartridge Heaters