Filament and resin consumption, print queues, printer capacity, and post-processing.
How the work runs
Filament or resin is consumed by weight, printers are the capacity constraint, and jobs queue. A print farm's economics live in grams per part, failure rate, and how much of the day the machines are running. Post-processing (supports, sanding, painting, assembly) is often more labour than the printing, and is the step most likely to be missing from a costing model.
What makes or breaks it
- Material consumed by weight, not by spool. Costing a part at 'one spool' is useless. You need grams, and you need the leftover on the spool tracked.
- Printer capacity and job queueing. Which machine, for how long, and what it displaces. This is your real constraint.
- Failure and reprint rates in the cost. If eight percent of prints fail, the successful ones cost more than the model says. Systems that ignore this over-report your margin.
- Post-processing as tracked labour. The finishing steps are usually where the hours go.
Where people get caught out
Using a general inventory tool that has no concept of consuming material by weight. You end up maintaining a parallel spreadsheet, which defeats the purpose of buying software at all.