You level the build plate, dial in exposure and press print — then an hour later the part is lying in the vat. For many resin newcomers, this is the moment that feels most mysterious. In most cases the culprit is not exposure or leveling at all: it is suction force.
What Suction Force Is
Every time an LCD printer pulls the build plate up, the cured layer has to detach from the FEP film at the bottom of the vat. That release creates a vacuum-like peel force. The larger the cross-sectional area of the part in the XY plane, the more surface sticks to the film, and the stronger the pull — to the point where the model can tear off the build plate or the supports snap.
The three forces working against you
- Peel force — the pull to detach each layer from the FEP.
- Gravity — the weight of the part and plate resisting the upward stroke.
- Adhesion to plate — how well the first few layers are bonded to the build plate.
Success is simply keeping adhesion stronger than peel force at every moment of the print.
Managing Suction with the Slice File
1. Tilt the part to reduce cross-section
This is the single most effective fix. Tilting a flat object 10–20° means each layer covers a much smaller area, so peel force stays low the whole way up. Flat-first orientation is the classic beginner mistake.
| Orientation | Layer cross-section | Suction risk |
|---|---|---|
| Flat (0°) | Large | High |
| Tilted (15°) | Small – medium | Low |
| Vertical thin | Very small | Very low |
2. Use a raft or stronger base
Adding a raft spreads the load across a wide, flat base that bonds firmly to the plate. Burn-in layers (the first 4–6) exposed for several seconds each give the base a strong grip. Many profiles use a burn-in exposure 6–10× the normal layer time precisely to win this battle.
3. Add supports at the edge, not just the bottom
Supports act like stakes holding the part in place. Placing heavier supports at the widest, heaviest points — often the lower corners — anchors the part against suction, while lighter supports at the top are easier to remove cleanly.
4. Lower lift speed at the start
Slower initial lift speed gives the film time to peel gently instead of snapping. Many users drop the first few layers' lift speed to 40–60 mm/min and only then ramp up. Combined with a slightly higher lift height, this dramatically reduces release stress.
A Quick Pre-Print Checklist
- Part tilted 10–20° to keep cross-section small.
- Raft enabled for wide or heavy models.
- Burn-in layers at 4–6 with strong exposure.
- Edge supports anchoring the widest section.
- Initial lift speed lowered, lift height adequate.
Getting these five points right will eliminate most "fallen part in the vat" prints. Of course, a consistent, calibrated resin helps too — a reliable standard resin with predictable behaviour is worth its weight in failed prints avoided. InnoStation 3D carries ANTINSKY Standard Resin for dependable everyday printing and the Standard Lite Resin where slightly lower viscosity and detail-friendly layers help. Both are tuned to work cleanly with the checklist above.