Custom CNC machining cost is driven by machine time, and machine time is driven by how much metal or plastic has to be removed, how accurately, and how many times the part has to be re-fixtured. Material is usually the second-largest line and rarely the largest. A useful rule of thumb for 2026: a simple part machined from aluminium in one setup lands between $5 and $50 per unit at volume; a medium-complexity part between $30 and $150; and a tight-tolerance part with multiple setups or secondary finishing between $100 and $1,000 or more. Prototype quantities are governed almost entirely by setup, not by material.
Key takeaways
- Machine time is the dominant cost driver, then material, then finishing. Setup dominates at prototype quantities.
- Quoted price falls steeply from 1 to 10 parts, then flattens. The second 100 parts are much cheaper than the first.
- Tolerance is the most expensive thing you can specify carelessly: blanket tight tolerances can double a quote for no functional gain.
- Five-axis capability removes setups and often costs less overall than a cheaper three-axis route with more fixturing.
- Above a few thousand parts, you should be comparing against injection molding, not against another machine shop.
In this guide
- 1. The five cost drivers
- 2. Indicative 2026 price ranges
- 3. How quantity changes the price
- 4. Material: what actually costs money
- 5. Tolerance, finish and the over-specification trap
- 6. How to get an accurate quote
- 7. When machining stops being the right process
- 8. How we quote machining work
1. The five cost drivers
Machine time
Machining cost is hours on a machine multiplied by the shop rate for that machine. Everything else in this list changes the number of hours. Removing a lot of material from a hard alloy with small tools on a light machine takes longer than the same geometry in aluminium on a rigid one, and the price follows.
Setup and fixturing
Every time a part has to be turned over or moved to a new fixture, someone has to indicate it in, and accuracy suffers as well as cost. Parts designed to be machined from two or three sides cost far less than parts that need five. At prototype quantities, setup is the whole quote.
Material
Aluminium is inexpensive and machines fast. Stainless and tool steels are slower to cut on top of being dearer per kilogram. Engineering plastics are cheap per kilogram but prone to moving and melting, so they take careful feeds and often need a stress-relief step. Material typically accounts for 15–30% of a total machining cost, more on small simple parts and less on complex ones.
Tolerance and inspection
A general tolerance of ±0.05–0.1 mm costs nothing extra. Precision work at ±0.005 mm requires light finishing passes, temperature control and CMM verification, and commands a real premium. Specifying precision across a whole drawing is the most common way a buyer overpays.
Secondary operations and finishing
Anodising, plating, heat treatment, bead blasting, laser marking and engraving are subcontracted or performed as separate operations, each with its own minimum charge. On a small batch, a $50 minimum anodising charge can be a large share of the unit price.
2. Indicative 2026 price ranges
These figures describe machined parts from common materials at normal commercial tolerances. Treat them as a budgeting anchor, not a quotation.
| Part type | Typical unit price at volume | What drives it |
|---|---|---|
| Simple part, single setup, aluminium | $5–$50 | Cycle time and material |
| Medium complexity, two to three setups | $30–$150 | Setup count and feature count |
| Complex precision part, tight tolerances | $100–$1,000+ | Finishing passes, inspection, scrap risk |
| Prototype batch of 1–10 parts | $150–$800 total | Programming and setup, largely fixed |
| Stainless or tool steel equivalent | 2–4× the aluminium price | Cutting speed and tool wear |
| Engineering plastics, tight tolerance | 1.5–3× the aluminium price | Fixturing, stress relief, careful feeds |
3. How quantity changes the price
The unit price curve is steep at the start and nearly flat at the end. Going from 1 part to 10 spreads the programming and first-article inspection over ten parts. Going from 100 to 1,000 spreads the fixture and the process tuning. Going from 1,000 to 10,000 mostly just consumes machine time, so the saving per part becomes small.
Three practical consequences:
- Always quote two quantities. Asking for 10 and 100 on the same RFQ tells you where the setup cost sits and often reveals that a larger batch is barely more expensive.
- Do not assume a big batch is cheap. Machining never reaches the unit costs of a moulded part, because the machine time never goes away.
- Consider a bridge batch. If the design may change, buy the quantity that covers validation and early sales, then move to tooling once it is frozen.
4. Material: what actually costs money
Three things make a material expensive to machine, and the purchase price is only the first:
- Machinability. Aluminium 6061 cuts freely. Stainless 316 work-hardens and needs gentler parameters. Tool steels are hard on tooling.
- Stock form. Plate, bar and near-net-shape blanks change both the price per kilogram and how much has to be removed. Buying a size that is close to the finished envelope is often the single biggest saving available.
- Stability. Some plastics and thin sections move after machining unless they are rough-machined, stress-relieved and finished in a second pass. That costs a second setup.
5. Tolerance, finish and the over-specification trap
A drawing with ±0.005 mm in the title block and nothing marked in the body is a signal that no one has decided which dimensions actually matter. The fix costs nothing and saves real money: tolerance the critical features, mark the rest as general, and say what the part has to do.
Surface finish behaves the same way. An Ra 1.6 µm machined finish is standard. Requiring Ra 0.4 µm means a separate finishing pass or a different process, and on a sealing face that may be justified while on a bracket it is pure waste.
6. How to get an accurate quote
Send a package, not a question. A quote that comes back in an hour from a one-line email is a guess, and it will change.
- 3D model in STEP or IGES, plus a 2D drawing for the tolerances and datum scheme.
- Material and grade, named exactly, including any condition such as T6 temper or hardened state.
- Critical tolerances flagged feature by feature, with the rest declared general.
- Surface finish and any secondary operations, with the areas they apply to.
- Quantity — give two, plus the annual volume if the part is going into a product.
- Function in one sentence. What the part does often lets a supplier suggest a cheaper route.
7. When machining stops being the right process
Machining is economical because it needs no tool. That same virtue sets its ceiling: every part carries its own machine time, so unit cost never falls to the level of a moulded part. Once annual volume is in the thousands for a small part, or the low hundreds for a simple one, price the injection option as well. The comparison is not machining versus a competing machine shop — it is machining versus tooling plus a low unit cost, amortised over the volume.
We cover that trade-off in detail in Injection Molding vs 3D Printing vs CNC Machining, and the tooling side in How Much Does a Plastic Injection Mold Cost?.
8. How we quote machining work
Our answer: we are a mould-making shop, so machining is our core competence rather than a side line. Our toolroom runs 13 CNC machining centres with travels up to 1,600 mm, six EDM machines including Sodick mirror-finish and twin-head units, three wire EDMs and five surface grinders — the same equipment that cuts our cavity blocks. We machine critical mould dimensions to ±0.005 mm, and a tool built to that accuracy holds ±0.01 mm on critical moulded dimensions, subject to the resin and the part geometry. Machined parts are checked on our CMM and shipped with a dimensional report. We make molds in-house and run trials and production through vetted partner factories, so if your volume eventually justifies a tool rather than machined parts, we can quote both against the same model instead of losing the job.
Related guides in this series
This article is part of our Injection Molding Processes Compared — a full walkthrough of the topic with the numbers and checklists behind each decision.
- Precision Machining vs CNC Machining: What’s the Difference?
- Injection Molding vs 3D Printing vs CNC Machining: Which Manufacturing Process Should You Choose?
- Low Volume Injection Molding: A Complete Guide to Small Batch Production
- 5 Key Factors That Affect Injection Mold Cost: Complete Pricing Guide
Get an engineering answer, not a sales pitch
Send us the model, the drawing and two quantities. We will come back with an itemised machining quote and, if the volume justifies it, an alternative tooling route priced against the same file. Talk to a manufacturing engineer.