Student Material 001: Post-Processing Workflow Quick Reference
Material ID: U2M4-MAT-001
Purpose: Quick reference guide for the complete resin print post-processing workflow
Format: Step-by-step workflow, timing charts, and troubleshooting guide
Updated: 2026-03-19
Complete Post-Processing Workflow
PRINT COMPLETE
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1. DRIP (2-3 min) — Let excess resin drip back into vat
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2. WASH STAGE 1 — Dirty IPA bath, 2-3 min, gentle agitation
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3. WASH STAGE 2 — Clean IPA bath, 2-3 min, gentle agitation
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4. DRY — Blot with paper towel + compressed air for crevices, 10-30 min air dry
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5. REMOVE SUPPORTS — Flush cutters, green state is easier
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6. UV POST-CURE — 405nm UV + heat (60°C), 5-15 min per resin type
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7. SAND — Progressive grits: 320 → 400 → 600 → 800 → 1000 → 1500
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8. FILL — UV spot filler for holes, CA glue for gaps
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9. PRIME — Spray filler primer, 2 light coats
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10. FINISH — Paint, clear coat, or leave primed
Wash Timing Guide
| Total Wash Time |
Result |
Recommendation |
| < 2 min |
Under-washed — tacky, resin residue |
Too short |
| 3-4 min |
Adequate for small, simple parts |
Minimum |
| 4-6 min |
Optimal for most parts |
RECOMMENDED |
| 6-8 min |
Acceptable for large/complex parts |
OK but monitor |
| 8-10 min |
Risk zone — possible surface softening |
Maximum |
| > 10 min |
Over-washed — whitening, cracking, warping |
TOO LONG |
UV Post-Cure Time by Resin Type
| Resin |
UV Only (20°C) |
UV + Heat (60°C) |
Signs of Completion |
| Standard |
8-15 min |
5-10 min |
Hard, non-tacky, slight color shift |
| Tough/ABS-like |
10-20 min |
8-15 min |
Firm, slightly less flexible than green state |
| Flexible |
15-25 min |
10-20 min |
Resilient, springs back from flex |
| Water-Washable |
5-10 min |
3-8 min |
Hard, non-tacky |
| Castable |
10-15 min |
8-12 min |
Hard, clean surface |
| High-Temp |
15-30 min |
Must use 60°C |
Very rigid, full hardness |
Warning: Do NOT exceed 2x the recommended time — over-curing causes brittleness and yellowing
Sanding Grit Progression
| Step |
Grit |
Method |
Purpose |
Time/Area |
| 1 |
320 |
Dry |
Remove support nubs and major marks |
30-60 sec |
| 2 |
400 |
Dry |
Smooth 320 scratches, blend transitions |
30-60 sec |
| 3 |
600 |
Dry or Wet |
Fine smoothing |
30 sec |
| 4 |
800 |
Wet |
Pre-finish smoothing |
30 sec |
| 5 |
1000 |
Wet |
Final smoothing for primer |
20 sec |
| 6 |
1500 |
Wet |
Polishing (for glossy/clear parts) |
20 sec |
Tip: Never skip more than one grit step — jumping from 320 to 800 leaves deep scratches
Spot Repair Guide
| Defect |
Repair Method |
Tools Needed |
| Support nub (raised) |
Flush cut then sand |
Flush cutters, 320-800 sandpaper |
| Support pit (concave) |
Fill with UV resin, cure, sand |
UV spot filler, UV flashlight, 800 sandpaper |
| Small hole/void |
CA glue fill, sand |
Superglue + accelerator, 600 sandpaper |
| Large surface defect |
Automotive spot putty, sand |
Spot putty, 400-800 sandpaper |
| Layer line visible |
Sand through progression |
400-1500 grit sandpaper |
| Crack |
CA glue into crack, sand |
Thin CA glue, 600-800 sandpaper |
| Broken piece |
CA glue bond, fill gaps |
Thick CA glue, accelerator, spot filler |
IPA Bath Maintenance Schedule
| Indicator |
Action |
| Dirty bath visibly cloudy/dark |
Replace with fresh IPA |
| Clean bath becoming cloudy |
Promote to "dirty" bath, replace with fresh |
| IPA not cleaning effectively |
Concentration has dropped — replace |
| After 20-40 small prints |
Replace both baths |
| Recycling used IPA |
UV expose → filter → reuse as dirty bath |
Post-Processing Troubleshooting
| Problem |
Cause |
Solution |
| Tacky surface after curing |
Under-washed or under-cured |
Re-wash in fresh IPA 2 min, then cure again |
| White/cloudy surface |
Over-washed (IPA penetration) |
Brief 30-sec re-soak in IPA, dry, cure; or sand 800+ grit |
| Part warped after curing |
Uneven heating, over-curing |
Cure with turntable; reduce cure time |
| Yellowing after curing |
Over-cured or UV degradation |
Reduce cure time; use UV-stable clear coat |
| Supports hard to remove |
Part was cured before removal |
Remove supports before post-curing next time |
| Part brittle/cracking |
Over-cured or wrong resin type |
Reduce cure time; switch to tough resin for functional parts |
| Surface rough after sanding |
Started with too-coarse grit |
Re-sand starting at 400 grit, progress to 1500 |
| Primer not adhering |
Surface contamination (IPA, skin oil) |
Wipe with IPA, let dry, re-prime |
Waste Disposal Summary
| Waste |
Disposal |
| Used IPA (dirty) |
UV cure → filter → solvent waste or recycle |
| Wash water (water-washable resin) |
UV cure dissolved resin → filter → drain |
| Paper towels with resin |
UV cure 10 min → regular waste |
| Sanding dust (cured resin) |
Regular waste (fully polymerized) |
| Cut supports (cured) |
Regular waste |
| Empty IPA containers |
Ventilate, then recycle |
| Spray primer cans |
Hazardous waste / aerosol recycling |
Last Updated: 2026-03-19