To price a resin print, cost the plate first and then split it between the parts on it. Machine time on DLP and MSLA printers depends on layer count, so on the tallest part, not on how many parts share the plate. Resin is the part volume plus supports and waste. On small parts, labour for washing, curing, support removal and inspection is usually the largest line, and tank film and LCD screens wear out at a rate you can put a number on.
Key points
- On DLP and MSLA, plate time is set by layer count; on laser SLA it also grows with the area scanned per layer.
- Resin cost is part volume (or hollowed volume) plus support struts and raft, plus waste.
- Wash, cure and support removal are labour, priced per plate and per part, and are never optional.
- Tank film and LCD screens are consumables with a life in layers or hours; charge them per job.
- Hollowing cuts resin sharply but needs drain holes and file preparation.
- A single small part on its own plate costs several times its share of a full plate.
How is resin print time worked out?
There are two families of vat machines, and they time differently.
DLP and MSLA (LCD). A projector or a masked LCD screen exposes the whole layer at once. Each layer costs an exposure time plus the time to lift the build plate, peel from the film and come back down. The first few “bottom” layers get a much longer exposure so the part sticks to the plate. So the plate time is roughly:
bottom layers × (bottom exposure + lift) + other layers × (exposure + lift)
The number of layers is the height of the tallest part divided by the layer height. Putting more parts on the plate at the same height adds almost nothing. That is the source of the classic resin pricing error, which our post resin printing is a labour business describes: the machine is cheap per part, so the cost hides elsewhere.
Laser SLA. A laser traces each cross-section, then the machine recoats. Time per layer grows with the area to be scanned, so on a laser machine more parts per plate does add time. Price laser SLA by scanned area per layer plus recoat time per layer.
How should the plate time be split between parts? On a masked or DLP machine the simplest fair rule is an equal share per part, or a share by footprint when parts differ a lot in size. A tall part that sets the plate height can reasonably pay a larger share, because it is the reason the plate takes as long as it does. On a laser machine, share by scanned volume instead, since that is what the laser spends its time on.
If you run DLP or MSLA, height is the variable to watch. Orienting a part at an angle, which resin usually needs for clean supports, increases its height and therefore its time.
How much resin does a part use?
Resin consumed is the part’s volume, plus the support struts, plus any raft, multiplied by one plus your waste allowance. A solid part uses its full mesh volume, unlike FDM where infill keeps material low.
| Component | How to estimate | Typical behaviour |
|---|---|---|
| Part | Mesh volume, or the shell volume if hollowed | Dominates for solid parts |
| Support structures | Supported envelope × a strut fraction | Often a few per cent of the envelope; calibrate it |
| Raft | Footprint × raft thickness | Small, fixed per part |
| Waste | A percentage on top | Resin left on parts, in the vat and on the plate |
Hollowing changes the first row the most. A large solid figure might need several times the resin of the same figure hollowed with a 2 mm wall. Hollowing needs at least one drain hole, usually two, and a check that no sealed cavity holds liquid resin: a trapped volume is a defect, not a saving. Wall limits for hollow parts are in our guide to minimum wall thickness.
Where does the labour go?
Resin post-processing is not optional, and it is skilled work. Split it into per-plate and per-part minutes:
| Activity | Charged per | Notes |
|---|---|---|
| File preparation, orientation, supports | Job or model | Longer for hollowed parts with drain holes |
| Plate set-up and clean-up | Plate | Resin top-up, vat check, plate scraping |
| Washing | Plate | Usually two baths; solvent is a consumable |
| Curing | Plate | UV and heat; machine time on the curing station |
| Part removal | Part | High-risk for delicate parts |
| Support removal and touch-up | Part | Scales with the number of support touch points |
| Inspection and packing | Part |
Support removal scales with how many touch points the part has, which you can estimate from its overhangs. Finishing beyond that, such as sanding, priming or a clear coat, belongs in surface finish options as buyer choices with their own minutes.
What consumables wear out?
- Tank film (FEP, nFEP, PFA). It wears with every peel. Treat it as a cost per layer: film price divided by the layers it lasts.
- LCD screen. On masked printers the screen is a wear part with a life in exposure hours. Treat it as a cost per hour of printing.
- Solvent. Isopropyl alcohol or a dedicated wash liquid, consumed by volume and costly to dispose of.
- Gloves, wipes, filters. Small per job, but real over a year.
Your own records of how many layers a film lasts and how many hours a screen lasts are the best source. A consumable with a known life is easier to price than a vague overhead percentage.
A worked example: a plate of twelve parts
Worked example: twelve small parts on one MSLA plate (example figures)
Plate: 40 mm tallest part at 0.05 mm layers = 800 layers. 6 bottom layers at 30 s exposure + 6 s lift; 794 normal layers at 2.5 s exposure + 6 s lift + 0.5 s light-off = 9 s.
| Line | Calculation | Amount |
|---|---|---|
| Plate time | 6 × 36 s + 794 × 9 s = 7,362 s | 2.05 h |
| Machine time | 2.045 h × €2.50/h | €5.11 |
| Resin | 12 × (8.0 ml part + 1.5 ml supports) × 1.05 waste = 119.7 ml × €60.00/l | €7.18 |
| Tank film | €15.00 ÷ 20,000 layers × 800 layers | €0.60 |
| LCD screen | €80.00 ÷ 2,000 h × 2.045 h | €0.08 |
| Labour per plate | 20 min set-up, wash, cure, clean-up | |
| Labour per part | 12 × 6 min removal, supports, inspection = 72 min | |
| Labour | 92 min × €32.00/h | €49.07 |
| Solvent, gloves, wipes | Per plate | €1.50 |
| Plate cost | €5.11 + €7.18 + €0.60 + €0.08 + €49.07 + €1.50 | €63.54 |
| Cost per part | €63.54 ÷ 12 | €5.30 |
Labour is €49.07 of €63.54, about 77 % of the plate. The machine is under a tenth.
Now print one of those parts on its own. Machine time, film and screen are the same (€5.11, €0.60, €0.08), resin falls to €0.60, labour falls to 26 minutes (€13.87) and consumables stay at €1.50. The single part costs €21.76, about four times its €5.30 share of a full plate. That is the arithmetic behind a resin minimum order value, and behind quoting a lead time that lets you batch small orders onto shared plates.
How should you set resin prices?
- Cost the plate, then share it. Machine time by plate, divided by parts or by footprint share.
- Put labour in minutes per activity, not as a percentage of machine time.
- Charge consumables by life: film per layer, screen per hour, solvent per wash.
- Make hollowing a visible option with its own preparation charge, and block quotes with trapped resin.
- Decide how you treat single parts: either a minimum per order, or a price that assumes a shared plate with a longer lead time.
The full cost structure that these lines fit into is in how to calculate 3D printing cost. If you are weighing resin against other processes for a part, FDM vs SLA vs SLS compares them on tolerance, finish, strength and cost, and print farm pricing covers how plate labour shapes the hourly rate when you run many machines.
Quotometry prices SLA, DLP and LCD resin with this structure: layer-based plate time per machine type, resin with supports and hollowing, tank and screen wear, and labour per plate and per part. The resin process page shows the settings a shop configures.
Questions people ask
Why does a full plate of resin parts take the same time as one part?
On a masked printer (MSLA or LCD) and on DLP, each layer is exposed all at once, whatever is on it. Time depends on the number of layers, so on the height of the tallest part, plus the lift and retract between layers. Adding parts at the same height adds almost no time. Laser SLA is different: the laser traces each cross-section, so more area per layer means more time.
How much resin do supports use?
Less than their envelope suggests, because a support structure is mostly empty space with thin struts. A few per cent of the supported envelope is a common starting assumption, but it varies a lot with support density, tip size and raft settings. Weigh a few supported prints before and after support removal and use your own figure.
Should wash and cure be an option the buyer can skip?
No. An unwashed or uncured resin part is sticky, weaker than it should be and unpleasant to handle. Wash and cure are part of making the part, so include them in every price. Offer further finishing, such as sanding, priming or clear coating, as options with their own minutes.
Is hollowing worth offering to buyers?
For larger parts, yes. A hollowed part uses a fraction of the resin of a solid one and is lighter. It needs drain holes so uncured resin can escape, and someone has to place them and check the file, so charge for that preparation. Never hollow a part without drain holes: trapped resin can crack the part later.
Quotometry prices every part from your own machines and rates, on your website, in seconds.