SLS (Fine Detail Resolution)

Step 1

Printing

The machine is loaded with a sieved and mixed blend of virgin and used polymer. Several layers of the powder are spread across the surface of the build bed. The machine is then switched on to heat the build chamber. When the chamber reaches the operating temperature, the first cross section of the build part collection is traced across the surface of the hot powder. The build chamber has been heated to a temperature just below the melting point of the chosen powder material, so when the laser touches the powder surface it gently translates it from solid to molten form. When the first cross section of the build part collection is complete, the build bed drops down by the selected layer height and another layer of hot powder is spread across the build plate and the laser traces out the next cross section. This bonds the molten layer onto the previous one below. The process is repeated until all of the build layers are complete and the collection of parts are encased within the build chamber that has filled as each layer is completed. The build chamber then needs to be allowed to cool down inside the machine. If the build chamber is removed too soon, parts will suffer thermal shock and can become distorted.

Step 2

Support Removal

Focuses on powder removal rather than physical support detachment and removal. Once cooled, the build chamber is removed from the machine and transferred to a de-powdering station. Here the base of the build chamber is pushed up to reveal the compacted block of powder commonly known as the build "cake". This is then broken down by hand to release the solid parts within, which are then brushed free of most of the surrounding loose powder.

Step 3

Surface Finishing

Sanding / Polishing Used to smooth the slightly grainy surface for aesthetic or functional reasons. Can be achieved with light sanding or vibratory polishing with a ceramic media. Chemical Smoothing / Coating Vapour smoothing is available for sealing and smoothing nylon surfaces. Colouring Often dyed using proprietary technology for consistent colour replication. Otherwise painted after priming; surface must be cleaned thoroughly. Gloss / Matte Control Surface is typically matte; a glossy finish can be achieved with coatings or polishing.

Step 4

Curing / Heat Treatment

UV / Thermal Curing Non-applicable. Annealing / Stress Relief Non-applicable.

Step 5

Assembly and Functional Finishing

Gluing or Bonding Cyanoacrylate (superglue) or epoxy works well with SLS nylon. Drilling / Tapping / CNC Common for adding precision holes or mechanical features. Inserts / Fasteners Threaded inserts can be heat-set or press-fitted post-print.

Step 6

Special Treatments

Infiltration / Sealing – Parts are occasionally sealed with epoxy or resin to reduce porosity. Functional Coatings Anti-bacterial, hydrophobic, or conductive coatings can be applied depending on the application.