What Micro Machined Parts Cost and Why Inspection Is Half of It
Buyers new to micro machining are often surprised by the price of a part that weighs a fraction of a gram. The surprise usually comes from looking at material. In a micro part, material is almost irrelevant. The cost sits in setup, machine time and tools, plus the work needed to prove the part is right: inspection, deburring, cleaning and documentation. This guide breaks down a typical micro machining quote and shows which drawing and RFQ choices change it. It follows on from the guide on how micro parts are measured, because inspection is a large part of the answer.
Where the money goes in a micro part
The table shows a typical breakdown for a tight-tolerance micro part at prototype and at production quantities. The numbers are illustrative shares, not a price list.
| Cost element | Prototype, 20 pcs | Production, 5,000 pcs |
|---|---|---|
| Material, incl. bar remnant | 2 to 5 % | 5 to 10 % |
| Programming and setup | 35 to 50 % | 2 to 5 % |
| Machine time | 15 to 25 % | 40 to 55 % |
| Tooling and breakage | 5 to 10 % | 8 to 15 % |
| Inspection and reports | 15 to 25 % | 10 to 20 % |
| Deburring, cleaning, packing | 5 to 10 % | 8 to 15 % |
Illustrative ranges for a part with several ±0.005 mm features. Actual shares vary by shop, process and geometry.
Two things stand out. At prototype quantities, the job is mostly setup and inspection. At production quantities, machine time takes over, but inspection and handling stay significant because they scale with the number of parts.
Setup and programming
Micro parts take real engineering before the first chip. A Swiss-type lathe may need 15 to 20 tools loaded and adjusted, overlapping operations programmed and the first parts measured and corrected. A 5-axis micro mill needs fixtures that hold a 5 mm part without distorting it, tool length and runout checks and a warm-up routine.
Several hours to a full day of setup is normal. On 20 prototypes, that cost is spread over very few parts. That is why the same part may be quoted at a high unit price for 20 pieces and a small fraction of it for 5,000. Asking for quotes at two or three quantities, and stating your expected yearly volume, lets shops choose the right process.
Machine time and tool wear
Micro tools cut with chip loads of a few microns per tooth. Even at 40,000 rpm or more, material removal is slow. Harder or tougher materials such as titanium and 316L force lower speeds and more frequent tool changes, as described in the guide to micro machining materials.
Tool breakage is a hidden cost. A 0.2 mm drill that breaks inside a part usually scraps the part and stops the machine. Shops price that risk in, especially for deep small holes or sharp features. A drawing that avoids the riskiest features pays for itself in scrap rate.
Why inspection is half of it
On large parts, a few checks with standard gauges cover most tolerances. On micro parts with tight tolerances, every critical feature needs a method that can resolve about a micron, which means CMM, vision system or dedicated gauges in a controlled room.
| Inspection requirement | Typical time per part or lot | Effect on price |
|---|---|---|
| Visual and pass / fail gauging, sample | Seconds per part | Low |
| Critical features on CMM, sample per lot | 10 to 30 minutes per lot | Moderate |
| First article report, 30 to 50 dimensions | 2 to 6 hours once | High on prototypes |
| 100 % CMM on several features | Minutes per part | Very high on volume |
| Material certificates, CoC | Admin time per lot | Low to moderate |
Typical values for orientation, not a quote.
For a small prototype run with a full first article report and several ±0.005 mm features, the CMM time can match or exceed the machining time. That is where the title of this guide comes from. It is not overhead. It is what makes a ±0.005 mm tolerance real.
Deburring, cleaning and packaging
Burrs on micro parts cannot be removed with a file. Shops use hand deburring under a microscope, abrasive or vibratory methods with fine media, electrochemical deburring or thermal deburring. Each adds time or a subcontract step. Parts then need ultrasonic cleaning and careful drying, and many are packed individually in trays or tubes so they do not tangle, bend or get lost.
If your drawing does not state the edge condition, shops either quote the most careful method to be safe or the cheapest and risk rejection. Neither helps you compare quotes.
How quantity changes unit price
The shape of the cost curve depends on the process.
| Quantity | Typical best process | Unit price trend |
|---|---|---|
| 1 to 10 | Micro mill or CNC lathe | Highest, setup dominated |
| 10 to 500 | Micro mill or Swiss-type | Falling fast |
| 500 to 5,000 | Swiss-type or dedicated mill setup | Low, cycle time dominated |
| 5,000 + | Swiss-type, multi-part fixtures | Lowest, tooling and handling matter |
Typical patterns, not rules.
Hypothetical example: a titanium dental component, ⌀3 x 7 mm, with an internal thread and two ±0.005 mm diameters. At 10 pieces, a shop quotes mostly setup and a first article report. At 1,000 pieces, the unit price may be a small fraction of the prototype price, because the same setup and report are spread across a hundred times more parts. If the buyer had asked only for 10, the production price would never have been visible.
Drawing changes that lower the quote
Most savings come from the drawing, not from negotiation.
- Relax non-functional tolerances. Apply ±0.005 mm only to fits and datums. Use ISO 2768 or a general tolerance block for the rest.
- Add inside corner radii. Sharp internal corners force smaller tools or EDM.
- Limit depth of small features. Keep pockets to about 3 times the tool diameter and holes to about 10 times the drill diameter.
- Choose a free-machining grade where allowed. 303 instead of 316L, C36000 instead of copper, when function permits.
- Define the edge condition and how it is inspected. For example “no burrs visible at 10x”.
- Match documentation to risk. A full first article report on every revision of a non-critical prototype is expensive.
The guide to feature sizes and tolerances in micro milling and turning lists more design rules in detail.
Costs buyers often forget
Some costs do not appear as a line on the quote but still end up in the total cost of the part. They are worth checking before you compare prices.
- Engineering changes. A revision after setup means reprogramming, new tools and often a new first article report. On micro parts, a small drawing change can cost as much as the original setup.
- Secondary processes. Passivation, anodizing, electropolishing, heat treatment and coatings are often subcontracted. Each adds lead time, transport and handling risk for very small parts.
- Special packaging. Individual trays, cleanroom bags or tubes for pins cost money and space. Bulk packing is cheaper but may damage parts.
- Freight and duties. Micro parts are light, so air freight is affordable, but duties and brokerage apply to every shipment. Consolidating deliveries often saves more than a lower unit price.
- Incoming inspection at your site. If you must measure every lot again because the supplier’s reports cannot be trusted, that cost belongs to the supplier choice.
- Scrap and requalification. A cheaper shop that fails a lot costs you time, a new trial order and sometimes a delayed product launch.
| Hidden cost | Typical trigger | How to limit it |
|---|---|---|
| Re-setup and new first article report | Drawing revision after order | Freeze critical features before ordering volume |
| Subcontract finishing delays | Coating or passivation outside the shop | Ask who does it and add it to the lead time |
| Incoming inspection | Weak or missing supplier reports | Agree methods and report format up front |
| Requalification | Supplier change after problems | Run a trial order before committing volume |
Typical patterns for orientation, not a complete list.
When two quotes differ, check whether these items are included, excluded or simply not mentioned. The lowest unit price is not always the lowest cost per good part delivered.
RFQ details that make quotes comparable
When quotes for the same part vary by a factor of three, it is usually because shops assumed different things. Put these in the RFQ:
- STEP model and PDF drawing.
- Material grade and standard.
- Quantities at two or three levels plus yearly volume.
- Tightest tolerance and the inspection method you expect.
- Documentation required: first article report, CoC, material certificates.
- Edge condition, surface finish and any coating.
- Delivery terms, such as EXW from the shop or DDP.
The list above is expanded in the micro machining RFQ checklist. To go from cost drivers to sending an RFQ and comparing the answers, read our guide to the micro machining quote.
Micropartz is a matching service. We send one complete RFQ to up to 3 shops that fit your process, material and tolerances, and reply within 24 business hours. Buyers pay nothing and order directly from the shop. When your drawing is ready, send an RFQ. Typical tolerances for planning are on the tolerance and materials reference.
Frequently asked questions
Why is a tiny part so expensive when it uses almost no material?
Because the price is driven by machine time, setup, small tools that wear and break plus the time needed to measure, deburr, clean and pack parts you can barely see. Material is usually a small fraction of the total.
How much of a micro part's cost is inspection?
It varies with tolerances and documentation. For parts with several ±0.005 mm features and a full first article report, inspection time can equal machining time on the first lots. For loose-tolerance parts it is a small share.
What is the fastest way to lower a micro machining quote?
Review which tolerances really matter. Relaxing non-functional features to ±0.02 mm or a general tolerance class, adding inside corner radii and stating realistic quantities usually saves more than switching supplier.
Why do quotes for the same micro part vary so much?
Shops choose different processes (Swiss-type, CNC lathe, micro mill), assume different inspection effort and price risk differently when the RFQ is incomplete. A complete RFQ narrows the spread.
Reviewed against
- ISO 2768-1:1989, General tolerances for linear and angular dimensions
- ISO 286-1:2010, ISO code system for tolerances on linear sizes
- Wikipedia: Engineering tolerance
Numbers in this guide are typical values for orientation. The drawing, the material certificate and the matched shop set the real ones.
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