How the cost of a CNC job is worked out
- Material: the price of a sheet or board divided by how many parts you nest on it. A $45 sheet of plywood that yields 8 signs is $5.63 a sign.
- Bit wear: bits wear out much faster than the machine, so they get their own line. A $30 end mill that lasts 15 cutting hours costs $2 an hour, so 6 minutes of cutting costs $0.20. Add a row for each bit the job uses.
- Machine time: the minutes your CAM estimates, at the machine's cost per hour: its price plus spoilboards, belts and spindle work over its life, divided by the hours it will run.
- Electricity: the spindle and machine's average draw, at your price per kWh.
- Setup: CAM work, fixturing and test cuts happen once per job and are spread across the parts, which is what makes a quantity discount real rather than a guess.
- Hands-on time: loading, tabs, sanding and finishing per part, at your hourly rate.
- Failure allowance: material, bit wear, machine time and power a scrapped part still uses.
Pricing CNC work
The suggested prices are margins after fees, solved directly so the fees can't eat the profit you aimed for. Many shops also quote with a rate card, materials at a multiple plus machine time at a shop rate. The true cost here tells you whether a rate card actually makes money on a given job.
Profit per machine hour
Machine time is what a CNC shop sells. Profit per machine hour shows which parts earn the most for the time they keep the spindle turning.