7 mistakes that erode margin in CNC quotes
Margin isn't lost on the shop floor: it's lost at your desk, when you prepare the quote. Here are the 7 mistakes we see most often — and how to eliminate them.
1. Hourly rates frozen for 5 years
Energy, labor and machines have gone up; your hourly rate hasn't. If you don't recalculate your hourly cost at least once a year, every quote starts with a 10-20% margin already eroded without anyone noticing.
2. Setup not allocated (or badly allocated)
Forgetting setup time on a small batch is the classic mistake that turns a single piece into a loss. The opposite is equally damaging: spreading 90 minutes of setup over a repeat batch that now takes 20 minutes to set up means uncompetitive quotes and lost orders.
3. Tolerances and finishes skimmed over
A missed H7, an Ra 0.8 assumed to be Ra 3.2, a 0.02 concentricity ignored: during production, extra passes emerge, external grinding, CMM inspections. But you've already signed the price. Systematic drawing review (or AI analysis) is the cheapest insurance there is.
4. Blank weight estimated by eye
On C40 the mistake is forgivable, on stainless less so, on titanium or Inconel it's a bloodbath: 1 kg difference on an Inconel blank is €60 lost per piece. The blank must be calculated from actual starting dimensions, with correct stock allowances — not 'by feel'.
5. Tooling considered 'free'
On tough materials, tool consumption represents 5-15% of part cost. Not putting it in the quote means giving it away. You need a tool cost per operation, calibrated to the material: the same insert that does 400 parts in aluminum does 40 in stainless and 8 in nickel alloy.
6. Single price instead of volume-based pricing
Quoting a single price for a single quantity produces two kinds of damage: on small batches you risk being below cost (setup!), on large batches you leave orders on the table that you would have won with a volume discount. A 5-tier price list (1/10/50/100/500) captures both situations with the same quoting effort.
7. No comparison between quoted and actual
The mistake that contains all the others: never measuring the variance between estimated and actual times. Without this feedback, the same mistakes repeat on every quote for years. Just the machine times from the CNC (or a stopwatch) and a monthly comparison are enough to discover patterns: 'on stainless parts I always underestimate by 20%'.
MachinePilot closes this loop automatically: you import actual Time Studies (Excel/CSV or CNC export), the system compares estimate and actual and recalibrates the parameters of YOUR machines. After a few weeks the estimate converges to ±8% accuracy — and every quote shows the real margin per operation before sending.