Cast-In Heaters

Cast In Heaters for Plastics Processing

Cast In heaters for all plastics processing applications including, air and liquid cooled barrel heaters, L-shaped heaters, vent cut out heaters, heat only cast in barrel heaters, air cooled with shroud, hollow cast nozzle heaters, and cooling jackets for cast in barrel heaters

Air Cooled Cast In Barrel Heaters

Finned air-cooled cast-in designs provide effective heating and cooling for plastics extrusion barrels. The fin pattern can be supplied as a standard height of 1″ or manufactured to a low profile thickness for small extruders or applications requiring rapid cooling. This pattern is designed to allow the optimal airflow around the casting for maximum cooling rates. Typically the forced air for the cooling function is driven by a shroud and blower system that is an integral part of the extruder, however these cast- in heaters can be utilized with an individual shroud and blower assembly for increased cooling control of the individual heater zones. All Durex cast-in barrel heater designs are available with mounting options of stainless steel locking straps or bolt-on clamping construction. Various electrical termination options are available for the air cooled cast-in heater depending on the application and environmental requirements.

Liquid Cooled Cast In Barrel Heaters

Liquid cooled cast-in barrel heaters are the most common cast -in heater design used on plastics extrusion barrels. The liquid cooling tubes run symmetrical to the heater element, which provides a uniform cooling pattern across the body of the casting. This cooling function dissipates heat rapidly from the cast-in barrel allowing a tight control of the melt temperature during operation. The typical liquid cooled design features a single diameter cooling tube of stainless steel or nickel alloy. The tubes can be supplied with no termination and plumbed at the location of the equipment, or other termination options such as cast-in threaded fittings can be supplied to minimize installation time. This cast-in design is also available with a dual cooling function. Although slightly larger in thickness, this design allows for a second cooling tube assembly, which can be employed, if the initial cooling line fails due to scale build up or cracking due to corrosion. All Durex cast-in barrel heaters are available with mounting options of stainless steel locking straps or bolt-on clamping construction. Various electrical termination options are available depending on the application or environmental requirements.

Air Cooled Cast In Heaters with Shrouds

L-Shaped Square Cast In Barrel Heaters

The “L” shape cast-in heater design is typically used on square and rectangular extruder barrels, which utilize a twin, screw design. In most cases, the high operating temperatures in these applications require these cast-in heaters to be constructed of a bronze alloy, however aluminum alloys are used for applications, which do not require the higher watt densities. While the most common design for “L” shaped cast-in heaters consists of heat only, they can be manufactured with cast-in cooling tubes. Typical mounting options include manufacturing the casting with 45° mounting flange which allows the cast-in heaters to be bolted and drawn together on the barrel or the cast-in heater can be supplied with mounting holes machined into the casting to mount directly to the barrel. The most common electrical termination for the “L” shape designs is a junction box mounted on to a vented tower that extends from the body of the casting. The box has a gasket for moisture resistance and can also be supplied with explosion proof specifications. The junction box can also be cast directly onto the heater. High temperature leadwire with a heavy-duty bronze braid is also available upon request.

Vent Cut Out Cast in Heater

Special sections of the cast-in extruder barrel such as a vent or feed throat require custom modifications to fit properly. These Vent/Cutout Cast-In Heaters are designed with element locations that maximize heater performance, but allow for special machined sections that could not be added to a standard barrel design.

Heat-Only Cast In Heaters

Although not a common design, heat only cast-in barrel heaters are available primarily with the stainless steel mounting strap option. This design is standardly 1″ thick and can be used with all standard electrical terminations that Durex offers. The cast-in heat only design can be used on piping areas that are typically more difficult to heat such as elbows and joint areas. The cast-in heater can also be cast directly onto pipe elbows or other areas to produce an integral heated part in specific applications such as feed pipes or heat exchangers. Designs are available in both aluminum and bronze alloys.

Hollow Cast Nozzle Heaters

The Hollow Cast nozzle heater design was developed by Durex to provide a maximum efficiency-heating device for plastic molders. Utilizing casting technology, a high performance mineral insulated heater is cast-in a bronze alloy and machined for a precision fit onto the injection nozzle. The heater is internally profiled along the length of the casting for optimal heat distribution under working conditions. Combined with the exceptional heat transfer qualities of the bronze alloy, this heater design offers superior performance over conventional nozzle or sprue bushing heaters. The Hollow Cast heaters are available with leadwire terminations that include Teflon and high temperature fiberglass with stainless steel overbraid or flexible armor cable.

Cast-in Cooling Jackets

Cast-in cooling jackets are manufactured for specific applications that do not require heat, but require a uniform cooling source, which can be controlled. The cooling jacket typically is 1″ thick with 1/2″ cooling tubes that are either stainless steel or Incoloy depending on the application. As with other liquid cooled designs, all standard cooling tube terminations are available.

Cast In Platen Heaters

Typical uses for platen heaters are heat transfer presses, foodservice equipment, die heaters, packaging equipment, and commercial pre-heaters. Manufactured from aluminum or bronze alloys, the platen heater consists of a tubular heating element that is designed and formed to provide maximum efficiency and temperature uniformity on the working surface of the casting.

Cast In Heaters for Semiconductor Processing

Durex Industries manufactures a line of cast-in aluminum and bronze heaters to meet the challenges of the most stringent requirements of the Semiconductor processing industry. Manufactured under the most rigid quality standards, these heaters are designed to deliver the performance that the industry expects and demands. Durex engineering will customize any of our heater products to meet your specifications.

Bake Platen Heaters

Utilizing state of the art heater technology, Durex manufactures precision cast-in bake platens specifically for semiconductor processing 200mm and 300mm wafers. The cast-in platen heaters are cast of pure aluminum (99.7%) to insure maximum operating temperatures of 450°C with minimum risk of process contamination. The casting process is controlled to eliminate any defects in the machined surface or casting body that would be caused by porosity. A mineral insulated heating element is distributed throughout the casting to provide surface temperature uniformity of ±1% or better of the process operating temperature. A hard-anodized finish provides an abrasion-resistant dielectric barrier on the working surface of the cast-in bake platen heater.

Bake/Chill Pedestal Heaters

The cast-in pedestal heater for semiconductor processing is basically a bake or chill platen that has an aluminum “neck” attached to the underside of the platen by electron beam welding. A helium leak test is performed to insure a vacuum tight assembly. The surface of the cast-in pedestal is precision machined with a flatness tolerance of .0005″ and typically includes lift pin holes and proximity pins per individual specifications. The cast-in pedestal heater can also include an integral temperature sensor as part of the assembly.

Bake/Chill Platen Heaters

The cast-in bake/chill platen heater for semiconductor processing has essentially the same operating specifications as the cast-in bake platen with the addition of a cooling function. A precision formed cooling tube is added as an integral component to the heater assembly in the body of the casting. This function can be used to rapidly cool the working surface of the cast-in platen or act as a heat exchanger for liquids or gases. A pressure test on the finished part assures the integrity of the cooling tube after the casting process. Various termination options are available to customize the cooling tube exits to existing or new applications.

Cast In Hot Chuck Heaters

Durex manufactures cast-in hot chucks or “heated tools” for semiconductor processing that deliver precise heat to wafers during the manufacturing process. These cast-in platens are individually customized with vacuum channels on the working surface, specific lift pin hole locations, and other surface or backside mounting holes. Manufactured from pure aluminum (99.7%), these cast-in hot chucks have a temperature uniformity capability of 1% of the process temperature and a flatness tolerance of .0005″ across the surface. A hard coat anodized finish is available or the surface can be supplied as a number 16-ground finish.

High Temperature Platen Heaters

When temperatures exceed the 450°C-temperature range offered by aluminum platen heaters, Durex offers a unique high temperature platen heater to extend the range available for a machined heater. The heater body is typically constructed of stainless steel, however other materials such as Nickel, Inconel, or Copper can be used. The assembly is provided as a single component. A precise groove is machined into the heater body determined by the heat profile requirements of the surface. A mineral insulated heating element is press fit into the groove to guarantee intimate contact with the heater body, which optimizes heater life and temperature uniformity of the working surface. In addition to high temperature platens, these units can be manufactured as pedestals and welded as vacuum tight.

Standard Pedestal Heaters

The standard cast-in pedestal heater manufactured by Durex for semicondcutor processing is designed to provide a quick solution for wafer processing applications. These cast-in heaters are designed specifically for 200mm and 300mm wafers. The standard design eliminates the need for costly tooling and mold design associated with new design custom heaters. They are ideal for research and development, rapid prototypes, and emergency repair requirements. A variety of options can be incorporated into the final cast-in product to customize the design for specific application requirements. These include a hard-anodized surface, lift pin holes, vacuum channels, and several electrical termination styles.