An LCD resin printer has an unusual property: on a masked machine, print time depends almost entirely on the number of layers and hardly at all on how much is in each one. One part or a full plate of parts takes nearly the same time.
This is wonderful for throughput and dangerous for pricing, because it means the machine is not where the cost is.
Where the cost actually is
Take the plate out. Drain it. Wash the parts - twice, in alcohol that is now dirtier. Dry them. Remove them from the plate, which for a delicate part is the highest-risk moment in the whole process. Remove supports, and then remove the little marks the supports left. Post-cure. Inspect. Bag.
On a small resin part this is fifteen to thirty minutes of skilled hands against forty minutes of machine time that would have happened anyway. If you price resin like you price FDM - mostly machine hours - you will quote a plate of thirty small parts at almost the price of one, which is roughly a factor of thirty wrong in the direction that hurts.
So price the labour by activity
Not as a percentage. As minutes, per activity, at the rate of whoever does that activity:
- plate preparation and file preparation, per job;
- part removal, per part;
- support removal, per part - and this one scales with how much support the part needs, which you can estimate from its overhangs;
- washing and curing, which is partly per batch and partly per part;
- inspection and packing, per part.
The person doing final inspection and the person pulling supports are usually not on the same rate. Model that.
The consumables nobody counts
Resin is obvious. What gets forgotten:
- Isopropyl alcohol, which is consumed per wash and which you eventually pay to dispose of.
- The FEP or nFEP film in the tank, which has a lifetime measured in print hours and is a real per-job cost.
- The LCD panel itself on a masked machine, which is a wear item with a known hour rating.
- Gloves, which sounds trivial until you count a year of them.
Model these as consumables with a lifetime, not as a vague overhead percentage. Then you can see which of your jobs are actually eating them.
Supports are resin, and resin is not cheap
The support envelope is not solid - only a few per cent of it actually cures. But “a few per cent” of a large support structure on an expensive engineering resin is a real number, and it is one of those coefficients that varies enormously with your support settings. It is worth calibrating rather than assuming.
Hollowing changes everything, so offer it deliberately
A hollow part with drain holes uses a fraction of the resin of a solid one. If you offer hollowing, the price difference should be visible to the buyer immediately, because it is the single biggest lever they have. And you should charge for preparing the file, because somebody has to place the drain holes and check that resin can actually get out.
Which brings us to the failure mode: a sealed cavity with no drain hole traps liquid resin that you will never recover, and produces a part that fails later. That is a DFM check, and it should block the quote, not the shipment.
Quotometry prices every part from your own machines and rates, on your website, in seconds.