3D printing with Projection Micro Stereolithography (PµSL) 

What is Projection Micro Stereolithography (PµSL) prototyping?

Projection Micro Stereolithography (PµSL) 3D printers build parts by curing photopolymer resins with light. In some ways the technology is similar to conventional stereolithography (SLA) and Digital Light Projection (DLP) but there are also significant differences. Parts are characterised by high accuracy, extremely fine detail and exceptionally smooth surfaces.

What is the PµSL build process?

PµSL builds parts, layer by layer, by curing a liquid photopolymer resin with ultraviolet light. In common with DLP, PµSL cures an area of resin with a single flash, rather than using a point of laser light as in SLA. However, the optics used in PµSL enable far higher resolution to be achieved than with DLP.

PµSL builds larger parts by moving the bed in the XY plane, so wider areas are cured with multiple projections of light. In contrast, DLP uses optics to extend the spread of the projected light, which comes at the expense of resolution.

The first cured layer is supported by the machine’s bed, then the bed is lowered into the resin bath by a distance equal to the layer thickness. Each subsequent layer is fused to – and supported by – the preceding layer. PµSL is normally used for building small parts, so the resin’s buoyancy means support structures are seldom necessary.

When the part is fully built, the bed rises out of the resin bath so the part can be removed, cleaned and any additional finishing processes carried out.