High Speed Sintering (HSS) is an additive process developed by Voxeljet to sinter plastic materials.

Sintering is often viewed as a process to use with metal materials. But, as various markets, like automotive and aerospace, turn to plastic materials to save weight, the ability to sinter with plastic powders is becoming an alternative to other ways to work with plastic, such as injection molding.

The Voxeljet process works with a range of plastics, including PA12, PP, TPU, PEBA and EVA

A key component of the HSS process is the control software–ProPrint. This open-source software lets users make precise, individual adjustments to any parameters. For example, the software allows free control of the energy input that melts the printed granulate. The layer thickness and ink input can also be configured individually.

In operation, the HSS process begins with a thin layer of plastic granulate applied to a heated build platform. An inkjet print head then moves over the entire platform and applies an ink that absorbs infrared light to areas that will result in the final part.

Then, an infrared lamp radiates the build platform. The plastic granulate is sprayed with ink that will absorb the light energy, causing the exposed powder to melt. The granulate not treated with the ink remains unbound.

The build platform is lowered by one layer of thickness, with more plastic powder applied, and then radiated. This process repeats until the part is complete.

Finally, the sintered part or parts are cooled in a temperature-controlled building area. After cooling, the desired component is removed from the powder and is ready for finishing. Finishing can include several options, including surface smoothing.
The powder that was not treated with the ink is processed for reuse.

The benefits of the HSS process include:
–Individual configuration of the temperature sources.
–Freely adjustable recoating speed, layer thickness, etc. to fine-tune the printing process.
–Varying powders with grain sizes of 30 micrometers up to 1.3 millimeters can be processed.
–IR lamp passes can be defined for firmer or softer component properties.
–Variations of applied amounts of ink.
–Process data can be individually analyzed, evaluated, and programmed.
–Full access to the printing system’s telemetric data.
–Bitmap-based printing. This allows the user to access the individual print layers (streamlining).
–Irrespective of the alignment of the components within the job box, components have isotropic surfaces in the direction of the X, Y and Z axes.

Source: Voxeljet.