Choosing the best sintering technology is key to controlling quality, repeatability, and cost of ownership. The materials being printed will typically determine the design of the equipment. Materials that sinter below 1150°C, such as carbon steel and aluminum, use a wire mesh belt furnace. Other materials, such as stainless steel, are sintered on a pusher furnace because the life of the wire mesh belt will be very short at these elevated temperatures.
Likewise, the atmosphere in the sintering furnace must match the needs of the process. An easily reduce oxide, such ae iron oxide, does not require the same amount of hydrogen that is needed to reduce the oxides of chromium.
Decades of research and experience have provided the basis for this innovative approach to the de-binding and sintering of binder jetted products. Temperature uniformity, atmosphere composition, and atmosphere flow characteristic are key variables that are critical to the development of the final density and distortion of printed components.
In a batch system, the center of the load sees a different heating and cooling cycle than the surface of the load because the heating and cooling are only presented to the load on the outer surfaces and must diffuse into the center of the load.
A continuous process has many independently controlled heating and cooling zones along the part’s path of travel. This provides each part with the same heating and cooling profile. The result is a more uniform part to part.
The simplicity of the continuous furnace provides a lower cost of ownership. Likewise, as the need for higher volume production grows, only a continuous furnace will provide the cost-effective quality at the high production rates.
Metal Additive Manufacturing often requires heat treatment to relieve residual stresses caused by the rapid heating and cooling during the 3D printing process. Annealing in an industrial furnace allows the material’s microstructure to stabilize, reducing internal stresses, improving ductility, and preventing potential warping or cracking in service.
FREQUENTLY ASKED QUESTIONS
How are industrial furnaces used in additive manufacturing?
Industrial furnaces are used for thermal steps such as debinding, sintering, stress relief, and heat treatment of additively manufactured parts. The required system depends on the feedstock, alloy, part geometry, and final property requirements.
Can additive manufacturing parts be processed in a continuous furnace?
Yes, when the material, production volume, atmosphere, and thermal cycle are compatible with continuous processing. Abbott can evaluate whether a belt furnace is appropriate for the application.
Why is atmosphere control important for additively manufactured parts?
Atmosphere composition, flow, dew point, and pressure can affect oxidation, carbon control, binder removal, surface condition, and final properties. Stable atmosphere control helps improve repeatability.
Can Abbott test an additive manufacturing thermal process before full-scale production?
Abbott’s research, development, and analytical capabilities can help evaluate thermal cycles, atmosphere conditions, and scale-up considerations before a production system is finalized.