Post on 18-Jan-2016
description
Finishing SLA
Priming SLA
It is advisable to spray a thin base-coat on the prototype part before sanding Give the part an even colour, reveal the
unevenness, holes, cracks and other surface defects which are difficult to spot
Act as a marker so that in subsequent sanding, it is easy to visualise which areas had been sanded
Reveal contaminations such as uncured resin on the part
Can Spray Demonstration
Sanding
Sandpaper is a form of paper where an abrasive material has been fixed to its surface; it is part of the "coated abrasives" family of abrasive products
Used to remove small amounts of material from surfaces, either to make them smoother (painting and wood finishing), to remove a layer of material (e.g. old paint), or sometimes to make the surface rougher (e.g. as a preparation to gluing)
Waterproof or wet/dry sandpapers use a resin bond and a waterproof backing
Adapted from: http://en.wikipedia.org/wiki/Sandpaper
Grit Size
Grit size refers to the size of the particles of abrading materials embedded in the sandpaper
ISO 6344 is an international standard covering the materials sizes and tests regarding sandpaper and other similar coated abrasives. It has three parts: ISO 6344-1:1998: Coated
abrasives, sizes and tests ISO 6344-2:1998: Macrogrit,
P12 to P220 ISO 6344-3:1998: Microgrit,
P240 to P2500
Grit Designation
ISO/FEPA Grit designation Average particle diameter
Material removal P60 0.269 mm
P80 0.201 mm
Sanding finishes P100 0.162 mm
P120 0.125 mm
Final sanding before painting P150 0.1 mm
P180 0.082 mm
P220 0.068 mm
Sanding finishes between paint coats P240 58.5 µm
P360 40.5 µm
P400 35 µm
P600 25.8 µm
P800 21.8 µm
Finishes before buffing
P1000 18.3 µm
P1200 15.3 µm
P1500 12.6 µm
Final sanding before buffing P2000 10.3 µm
P2500 8.4 µm
Material removal
Use #60 to #100 for material removal
Use a rigid sanding block whenever possible
Wrap the paper around half-round or round sanding-block to shape concave surfaces
Dry or wet sand Use the hand to feel the
surfaces
Face by faceFrom large face to smallFrom flat face to pronounceKeep small protrusion and fillets
untouched
Use chisels to clean negative sharp corners
Sanding finishes
Change to #200 - #400 paper
The base-coat will be removed gradually to reveal body material
The target is to ‘replace’ previous coarse sandpaper strokes with finer strokes
The progress will be fast at the beginning and will slow down when the surf
Progressive Sanding
A: Thoroughly sanded away all previous strokes
B: Leave a trace of previous strokes
C: Change sandpaper pre-maturely
D: Use finish sanding to ratify unevenness of C
A
B
C
D
Spray Painting
AdjustmentCleaning before sprayTypes of paintPaint mixingSequencing the strokesSpraying direction and movementCleaning after sprayDrying