Tuesday, July 22, 2014

Have You Considered a Cast-in Heated Part?

Cast-in semiconductor chuck heater
When OEMs (original equipment manufacturer's) look for the best way of adding heat to their equipment, they're faced with the same choices - clamping, bonding or inserting. But there's another, more efficient and productive way to go - cast-in aluminum or bronze heaters.



Chuck heater side view
Casting an electric heating element into an aluminum or bronze shape is pretty simple. Its very much like any other casting process, except there's a heating element inside. A formed tubular type element, sized with the proper wattage for the work required, is carefully placed inside a mold and molten metal is poured in. Once cooled, the rough casting is then processed as would any other cast part.

Because thermal efficiency is a function of the contact between heater element and the part to be heated, cast-in heaters provide one of the most energy efficient ways to heat something. Unlike clamped on, or bonded heaters, there is no wasted energy from backside losses. And unlike a heater inserted into a bored hole, even the slightest fit tolerance losses are avoided.
Electrically Heated Cast-in Tray
Because of the thermal conductivity of aluminum (or bronze), uniformity is another advantage to cast-in heaters. When a cooling tube is cast-in to the part as well, these types of heaters can provide excellent controllability.
The cast-in heater can be supplied in just about any size or shape as well. If it can be cast, then you can probably design and fabricate a cast-in heater.  Some examples of how cast-in heaters are used are:
  • Injection molding barrel heaters
  • "Clam-shell" cooking surfaces
  • "Semiconductor "chuck" heaters
  • Medical sampling containers
Considering the heater and the part are one piece, its hard to compare pricing to clamp on, or bonding heater approaches. Additionally, cast-in heaters may also require some non-recurring engineering costs for the design. However, when you consider the overall performance, efficiency, labor and inventory, cast-in heaters present a very strong argument for adoption.

If you're interested in learning more about cast-in heaters, feel free to call Belilove Company Engineers at (510) 274-1990.