What Does CNC Milling Cost? The Cost Drivers Explained Honestly
Knowledge · CNC machining
What makes up the price of a milled part?
Five blocks with very different weights per order. Programming (drawing review, CAM program, tooling selection) occurs once per part. Set-up (fixtures, tool measurement, zero point, first article) occurs once per order. Runtime is the actual cutting time per piece. Add material including cut-off and waste, and inspection with optional reports. On a one-off, programming and set-up often make up half to two thirds of the price; only in series does the ratio tip towards runtime.
Why does the hourly rate alone say so little?
Because it prices only one of the five blocks and says nothing about efficiency. A shop with a modern machining centre and a sound clamping concept can deliver cheaper at a higher rate than a low-cost supplier who sets up twice as long, clamps twice and reworks the first article. Only complete prices for defined parts are comparable, never rates. On large parts, experience and metrology additionally decide the scrap risk; see machining large parts.
Which cost drivers does the buyer control?
| Cost driver | Effect on price | Your lever |
|---|---|---|
| Tight tolerances without function | extra machining and measuring steps | ISO 2768-m as default, fits only with reason |
| Sharp internal corners | special processes such as EDM | allow internal radii from R4 |
| Exotic materials | procurement time, minimum quantities | prefer S235/S355, 1.4301, standard aluminium |
| Unfavourable raw sizes | material and cutting time | design to common plate and bar sizes |
| Quantity 1 despite foreseeable demand | set-up block carried by one part | order spare demand at the same time |
| Fine surfaces everywhere | extra finishing passes | surface specs only on functional faces |
How strongly does quantity push the unit price?
Substantially, without any discount from the manufacturer. A worked example: 2 hours programming and set-up, 20 minutes runtime per part. The single piece carries 2 hours 20 minutes; at 5 parts it is 44 minutes each, at 20 parts 26 minutes. The unit price more than halves purely through distribution of the fixed block. The most useful buyer question is not “any movement on price?” but “what does it cost if we take five?”.
What belongs in an enquiry for a reliable quote?
PDF drawing, STEP model, material, quantity, tolerance and surface requirements, required documentation and delivery date. The more complete the package, the less safety margin sits in the quote, because every uncertainty gets priced. A call before design release is the cheapest consulting appointment there is.
Frequently asked questions
What does a CNC milling hour cost?
It varies with machine size, region and automation; small 3-axis machines sit well below large machining centres for multi-metre parts. Only the complete price per part is meaningful, because programming and set-up overshadow the rate.
Why is the first part so expensive and the second so cheap?
Because programming, set-up and first-article inspection occur only once. The second part essentially costs runtime and material.
Is comparing quotes by hourly rate useful?
No. Compare complete prices for a defined part including all secondary services. A low rate with long machining time is dearer than a higher rate with efficient production.
How can design reduce costs?
Four levers: tolerances only with function, generous internal radii, standard materials and common raw sizes. Together they regularly save a double-digit percentage.