Differences in technologies and materials

Selective Laser Sintering


Selective laser sintering (SLS) is a rapid prototyping technique that uses a laser likely CO2 laser as the power source to sinter powdered material namely polyamide and polystyrene powders, aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.

In SLS technique nylon(namely polyamide and polystyrene) is used as build material. In this technique, the build material will be in powder state. This powder is fused selectively by a laser according to the data given at the time of design.

Stereolithography (SLA) is also known as optical fabrication , is a form of 3D printing technology which is used for preparing a prototype in a layer by layer fashion using photochemical processes by which light causes chemical monomers and oligomers to cross-link together to form polymers. Those polymers then make up the body of a three-dimensional solid.

In SLA technique photo polymer resin(namely clear resin , castable resin, standard resin) is used as build material. In this technique, the build material will be in liquid state. This resin is cured,layer by layer accordingly by the laser that is beamed.

Differences in Properties

Property Selective Laser Sintering Stereolithography
Build/Bed volume 200x250x330 mm 145x145x175 mm
Layer Thickness 0.06mm to 0.12mm 0.05mm to 0.15mm
Accuracy ±100microns ±50microns
Minimum Wall Thickness 1mm 5mm
Laser Type UV laser beam Co2 laser
Sensitivity Long exposure to UV light damages the object  High Brittleness
Surface Finish Very Rough Surface Finish  Smooth Surface Finish
Build material Powdered nylon Resin(namely PA2200) Liquid Photo-Polymers,Photo-sensitive resins
Post Processing Dusting and possible Sanding  UV baking and removing support structures
Applications  Functional prototypes,short run,bridge or custom manufacturing Patterns, molds,dental and jewellery applications

Sample parts

Selectively Laser Sintering


SLS(on left) vs SLA(on right)


Which technology is cost effective when compared between SLS and SLA

Comparatively SLS will be low cost because of the price of  build material and post processing techniques.

In which technology better surface finish is achieved SLS or SLA

In SLA technology we will achieve better surface finish because of  build material properties, output will be like moulded plastic part

In order to achieve toughness, which technology is preferred either SLS or SLA

SLS will be preferred because the build materials are typically nylon and hence tougher than average SLA resins

In which technology we can get clear prototype

SLS has no chance to get clear output , whereas in SLA some resins are translucent and some are clear. To get clarity, you will need to polish the build part

Which technology is used for fabrication of hollow parts in 3d printing

SLS is used for manufacturing of hollow parts as there is no support generation required whereas in SLA support generation is a mandatory step, which will be tough to remove supports during post processing, in case of hollow parts

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