CNC Cost Driver Checker
Answer eight questions about your part and see what is actually driving its cost — and what you could change to bring it down. This is the same design-for-manufacture thinking we apply free with every enquiry, made self-serve. It deliberately doesn't quote you a price: an honest number needs your drawing. No sign-up.
The single tightest callout, not the general note.
Leave at 3.2 if as-machined is fine.
e.g. a 40 mm deep, 20 mm wide pocket = 2.
0 = sharp internal corner.
What actually makes a CNC part expensive
Machining cost is mostly time on the machine plus setups plus anything that is not cutting — inspection, secondary processes, and scrap risk. Almost every expensive part is expensive for one of a small number of reasons, and most of them are decided at the design stage rather than the quoting stage.
Tolerances are the classic. A tolerance tighter than the general class has to be produced and proven — slower passes, more careful setups, more inspection, and a real scrap risk if it drifts. That is entirely justified on a bearing fit and entirely wasted on a clearance hole. The most common saving we find in a DFM review is simply tolerances that were tightened by habit rather than by function.
Deep pockets and small internal radii are the next. A pocket deeper than about 3–4× its width forces a long, slender cutter that chatters, so feeds drop and cycle time climbs. Small internal corner radii force a small cutter for the whole pocket, not just the corners — increasing a 2 mm internal radius to 5 mm can transform the cycle time. Note that a truly sharp internal corner is impossible to mill at all: a round cutter always leaves a radius. If you genuinely need a sharp corner, that means EDM or a corner relief, and it is worth designing in deliberately rather than discovering at quotation.
Setups matter more than people expect. Every time a part is re-fixtured, someone is paid to do it and a tolerance stack-up is introduced. A part machinable from one or two sides is meaningfully cheaper than the same part needing five. This is exactly what 5-axis machining addresses — the DN Solutions DVF 5000 produces complex geometry complete in a single setup, removing both the labour and the stack-up.
Material and quantity close it out. Machinability is a cost multiplier: brass and aluminium cut fast, titanium and nickel superalloys punish tooling and demand conservative parameters. And quantity amortises setup — the first part carries all the programming and fixturing, so unit price falls steeply from one-off to batch. If you are prototyping now but will produce later, tell us; we will program with that in mind.
CNC machining cost — FAQ
What makes a CNC machined part expensive?
Mostly machine time, number of setups, and non-cutting work like inspection and secondary processes. The biggest design-side drivers are tolerances tighter than needed, deep pockets, small internal corner radii, thin walls, many faces requiring re-fixturing, and hard-to-machine materials.
How can I reduce CNC machining costs?
Loosen tolerances that do not need to be tight, increase internal corner radii, avoid pockets deeper than about 3–4x their width, reduce the number of faces needing machining, choose a more machinable grade where the application allows, and order in batches to amortise setup. A free DFM review will identify which of these actually apply to your part.
Why do tight tolerances cost more?
A tight tolerance must be both produced and proven. That means slower cutting passes, more careful setups, additional inspection, and a genuine scrap risk if the process drifts. Our standard is ±0.010 mm (ISO 2768-f); tighter is achievable on critical features but should be specified only where it is functionally needed.
Can CNC machining produce sharp internal corners?
No — a rotating cutter is round, so it always leaves a corner radius. Sharp internal corners require EDM or a designed-in corner relief. If your design shows a sharp internal corner, it will be queried at quotation, so it is worth deciding deliberately what you want there.
Does quantity reduce the price per part?
Significantly. Programming, fixturing and first-article inspection are largely fixed costs carried by the first part, so unit price drops steeply from one-off to batch. We have no minimum order — single prototypes are welcome — but if you expect to produce later, tell us and we will program accordingly.
Do you offer a DFM review?
Yes, free with every enquiry. We identify cost drivers and tolerance risks before a single tool is touched, and we would rather tell you the cheaper option than quietly machine the expensive one. Send a PDF drawing or CAD file for a same-day quote.
Send Your Drawing for a Same-Day Quote
Talk directly to the engineers who will machine your parts — no account managers, no trading-company markups. Complimentary DFM review with every enquiry.