How Selective Heat Sintering (SHS) Works
The term "3D printing" refers to building up an object additively. This is accomplished using a number of different methods. Selective Heat Sintering is one type of 3D printing process.
Overview
Selective Heat Sintering systems are manufactured by BluePrinter, and work by using a thermal printhead to apply heat to layers of powdered thermoplastic. When a layer is finished, the powder bed moves down, and an automated roller adds a new layer of material which is sintered to form the next cross section of the model. SHS is best for manufacturing inexpensive prototypes for concept evaluation, fit/form and functional testing. SHS is a metal additive manufacturing technique similar to Selective Laser Sintering (SLS), the main difference being that SHS employs a less intense thermal printhead instead of a laser, thereby making it a cheaper solution, and able to be scaled down to desktop sizes.
Examples
Materials
BluePrinter offers thermoplastics in powder form which have properties similar to nylon. They currently only produce a very limited, monochrome selection. However, the amount of materials available for this process does not reflect a technological limitation of the process, but rather, the speed at which BluePrinter can offer a wider selection for their patented process. The finished object’s strengths and quality are comparable to those created using Binder Jetting.
How it works
The build takes place in a bed of powder encapsulated by a tightly controlled chamber. During production, a thin layer of metal powder is spread evenly across the build chamber by an automated roller. The powder bed is held at an elevated temperature so the plastic powder is at an optimal temperature for sintering. The print head starts to move across the powder and, as it moves, applies heat to bring the material to just below its melting point and solidifies the material to create the object. A new layer of powder is then spread over the top of the previous layer and the thermal printhead then begins to form the next cross section. When fully built, the object is surrounded by unmelted, excess powder. That excess material cradles the object in the printing process, providing support for complex geometries and overhangs which might require dedicated supports using other 3D printing processes.
After printing is completed, the excess powder must be removed. Powder removal is usually done at a separate powder removal station. This excess powder can then be reused for further prints. SHS is employed in Blue Printer’s desktop-sized rapid prototypers that come in a very manageable size compared to other powder bed fusion 3D printers. However, a small build volume and limited selection of materials means that SHS prototyping is currently restricted to printing small, white models.