The Print Comes Off the Plate Wet, Sticky and Not Yet Finished
LCD resin printing has a reputation problem: people judge it by the printer. In reality, most “failed” resin prints did not fail in the vat — they failed at the wash-and-cure bench. A sharp 16K panel will happily hand you a part with beautiful detail, and that part will still turn soft, cloudy or dimensionally wrong if the post-processing is rushed. This guide covers the workflow that converts a raw, dripping print into a stable, finished piece.
Why Post-Processing Decides the Outcome
After printing, the surface of your part is coated in uncured resin. Left alone, that residue continues to cure unevenly under ambient light, fills fine detail, and can cause skin irritation on handling. The job of post-processing is threefold:
- Remove excess liquid resin before it cures in the wrong places.
- Clean the surfaces and internal channels so no trapped resin remains.
- Cure the part fully and evenly so it reaches its final mechanical properties.
Skip any one of these and the part under-performs — no matter how good the exposure was.
Step 1 — Let It Drain, Don't Drip Everywhere
When the build plate lifts, hold it over the vat for a moment and let the bulk of the resin run back. Then remove the part with a scraper and set it on a drip tray. Two minutes here saves you a much messier first wash.
Practical notes:
- Work in nitrile gloves and eye protection — uncured resin is a sensitiser.
- Remove supports before curing. Cured supports snap and can tear surface detail; green (uncured) supports cut cleanly with flush cutters.
- Keep a dedicated tray so drips don't contaminate your bench.
Step 2 — Wash in Two Stages
One dirty jar is the most common mistake. Use two containers:
| Stage | Purpose | Time (typical) |
|---|---|---|
| Wash 1 (dirty) | Strip the bulk residue | 2–4 min |
| Wash 2 (clean) | Final rinse of all surfaces | 1–3 min |
IPA (isopropyl alcohol) around 95%+ is the standard. Agitate gently or use a wash station; excessive time or vigorous brushing can dull fine detail and soften thin features. For hollow parts, flush the interior through the drain holes — this is non-negotiable.
Water-washable resins exist and skip the alcohol, but check the manufacturer's guidance; they still benefit from a clean second rinse.
Step 3 — Dry Completely Before Curing
Residual alcohol trapped in crevices will flash, cloud the surface, or leave white residue. Blow the part dry with compressed air or let it air-dry fully. If the surface still looks wet, it is not ready for the cure chamber.
Step 4 — Cure Evenly, Not Forever
Under-curing leaves a part soft and dimensionally unstable; over-curing makes it brittle and can warp thin sections. A rotating cure station with the correct wavelength (typically 405 nm) gives even coverage.
| Part type | Typical cure | Watch out for |
|---|---|---|
| Small miniatures | 2–4 min | Over-curing fine tips |
| Medium functional parts | 4–8 min | Uneven coverage on one side |
| Hollow / thick walls | 8–15 min, rotate | Trapped resin inside |
Always check the resin datasheet first — the right window depends on the material, not the machine.
Matching Resin to the Job
Post-processing can only reveal the quality a resin already has. For predictable results and easy calibration, a dependable baseline photopolymer such as ANTINSKY Standard Resin 1KG is the sensible starting point. When a model lives or dies on fine detail — miniatures, jewellery masters, intricate miniatures — reach for ANTINSKY Standard Lite Resin, which cleans and cures into a crisp surface. For parts that will be handled, dropped or assembled, a tougher formulation such as ABS-Like Resin holds up better than a brittle standard grade.
Common Post-Processing Faults and Their Causes
| Symptom | Likely cause | Fix |
|---|---|---|
| Cloudy / white surface | Resin residue cured on the part | Longer second wash; dry fully |
| Sticky after curing | Under-cure or inhibitor layer | Extend cure; ensure rotation |
| Lost fine detail | Over-washing / over-brushing | Shorter wash; gentler agitation |
| Warping after cure | Over-cure on thin walls | Reduce time; support while curing |
| Cracks later | Trapped resin in hollow part | Drain holes + internal flush |
A Workflow Worth Repeating
- Drain over the vat, then remove the part.
- Cut supports while green.
- Wash in two stages; flush hollow interiors.
- Dry completely — air or compressed air.
- Cure on a rotating station for the datasheet's window.
- Inspect, then finish or assemble.
Do this consistently and your “success rate” will rise without touching a single exposure setting. Sharp hardware plus disciplined post-processing is what actually produces a finished resin part — not the pixel count alone.
Find the resins referenced above, plus films and wash-and-cure accessories, at innostation3d.com.