STEREOLITHOGRAPHY  SLA

Sterolithograpgy or SLA is one of the oldest 3D-Printing or Additive Manufacturing process.
A UV-laser beam cures the liquid photosensitive Epoxy resin layer by layer. After 1 layer is cured the build platform lowers down into the resin tank by 0.1mm or the layer thickness that is prepared for the build. This process can build as many parts that can fit on the platform so no stacking is possible.

Advantages:
Accurate
Smooth surface
Large sizes without warping
Very detailed parts & features
Easy to finish for painting
Can be used for funstional test
Can be used for and end products

Disadvantages:
Supports neccesary
Unpainted UV-Yellowing occurs
Standard Epoxy resins have low HDT
Always needs finishing after curing
No living hinges possible

VRT SLA-Machines and Resins
Dimension: 450x450x400
Material: VRT-Clear
suitable for: Transparent parts and Lost Metal Castings ( best burn out resin)

Dimension: 600x600x450 
Material: VRT-Somos-GP-Plus 
suitable for: Rigid and strong parts in yellow/white color

Dimension: 850x850x500 
Material: VRT-White
suitable for: Flexible functional parts in yellow/white color. Good for snap-fingers

Dimension: 1000x1000x600 
Material: VRT-Somos Ledo 
suitable for: Flexible and durable parts for Rapid Manufacturing of small series

Mechanical properties at a glance:

Material: Tensile Strength at break ASTM D638
Color:
Clear 45-60
Yellow/White 40
Off-White 30
White 50

Material: Elongation at Break ASTM D638
Color:
Clear 11-20% 
Yellow/White 6-9% 
Off-White 12-20% 
White 11%

Material: Flexular Strength ASTM D638-
Color:
Clear 78-83 Mpa 
Yellow/White 67Mpa
Off-White 69-74 Mpa 
White 50Mpa

Material: IZOD Impact ( Notched) ASTM D256
Color:
Clear 38-48 J/ cm 
Yellow/White 23-29 J/cm 
Off-White 58-70 J/m 
White 36 KJ/m

Material: HDT at 0.455 Mpa ASTM D648
Color:
Clear 52 °C
Yellow/White 46 °C 
Off-White 52 °C
White 58 °C