So then, how many 3D printing technologies are out there?
FDM – Strong functional parts that use thermoplastics. A molten bead of plastic is deposited like a glue gun layer upon layer. Great technology for working prototypes, jigs and fixtures and end use parts for small batch production
Polyjet – A UV cured resin that is very similar to inkjet technology. Microscopic droplets of the resin are deposited on the layer beneath it and a UV light immediately cures the resin. Polyjet is great for 3D printing where feature detail capture and aesthetics are important.
SLA – The grandfather of 3D printing, SLA uses a a vat of resin and a laser ‘dances’ over the meniscus layer of the vat solidifying the layer. The growing model then sinks into the vat and the next layer is 3D printed. Very good for feature detail but expensive to purchase and run. Quite a lot of 3D printing service bureaus have a SLA machine because of that.
SLS – Like SLA but it uses a powder, typically glass filled nylon that is sintered by the laser. The finished parts are enveloped into a cake of powder when the build is complete. It is then left to stabilise due to the heat and then all the parts are broken out of the ‘cake’ and then cleaned.
Powder by Z-corp – Again, another powder process however the powder is more of a chalk or starch and is very brittle. No Lasers are used so each layer is sprayed with a solidifier where required on the layer. Parts are still brittle so a further process is required coating the parts in a ‘super glue’ liquid.
DMLS – Metal Sintering is the latest and greatest Additive Manufacturing process very similar to SLS but it uses ‘talcum powder’ size particles of metal. Precious metals can be used also so its finding a home in bespoke jewellery but is not as yet being found in mainstream industry apart from research institutions.