Why a Machined Medical Component Costs What It Costs

September 21, 2026

Two shops quote the same drawing and come back 60 percent apart. Neither of them is wrong. They are quoting different amounts of work, because the drawing left room for that.

Here is what actually sits inside a medical machining quote, ordered roughly by how much of the gap each one explains.

Material and the certificate behind it

Implant grade bar is expensive, and the certificate is a large part of why.

Ti-6Al-4V ELI released to ASTM F136 carries controlled interstitial limits and a mill certificate that ties the bar to a heat. Commercial Grade 5 does not. Cobalt chrome to ASTM F1537 is bought in small traceable quantities from a short list of mills. Implant grade PEEK to ASTM F2026 is sold with a compliance history that general PEEK does not have.

On a small part in a small lot, bar cost can be a third of the quote. It is also the line you have the least control over, because the material is usually fixed by your regulatory file.

What you can change: nothing on an implant. On a non-patient-contacting part, ask whether the implant grade is actually required or whether it was copied across from another drawing.

Tool life

Titanium has low thermal conductivity, so the heat that would normally leave in the chip stays in the cutting edge. Cobalt chrome is simply hard. In both cases the tooling line on a medical quote can be larger than the machine time line.

This is why surface speed on titanium looks slow to anyone used to aluminium, and why a shop that quotes titanium like steel comes in cheap and then asks to renegotiate.

What you can change: internal corner radii. A 2 mm radius instead of a 1 mm radius lets the shop use a stiffer tool at a higher feed, and it often changes nothing functionally.

Tolerance and surface finish

A ±0.05 mm part and a ±0.005 mm part are different process routes, not the same route done more carefully. The tight one adds a finishing pass, an in-process check, probably a temperature-controlled inspection and often a scrap allowance.

Surface finish is worse, because below about Ra 0.4 micrometre on a bearing or mating face you are usually into polishing, and polishing is hand work. Hand work does not get cheaper with quantity.

What you can change: this is the biggest lever you have. Tolerance blocks get copied from drawing to drawing for years. Check the stack and loosen anything that is not carrying a function.

Documentation and validation

First article inspection against the drawing revision, a dimensional report, lot records, a certificate of conformity and, where the process needs it, IQ, OQ and PQ evidence.

These are real hours by a person who is not making parts. On a lot of 50 they can exceed the cutting time. On a lot of 5,000 they disappear into the noise, which is why medical quotes look so much worse at prototype quantity than in production.

What you can change: the number of separate revisions and lots. Every new revision is a new first article. Batching a year of releases against one revision is often the single cheapest thing a buyer can do.

Post-processing

Passivation to ASTM A967, electropolish to ASTM B912, titanium anodising, laser marking, cleaning and controlled packaging. Each is an operation, most involve a handoff, and every handoff adds days as well as cost.

Marking deserves its own note. A UDI mark that has to stay readable after passivation and several hundred autoclave cycles is a developed process, and on a loaded surface it also has to be placed where it does not start a crack.

What you can change: ask whether a treatment is on the drawing because the part needs it or because the template had it. Bead blast before passivation is frequently the second one.

Lot size and setup

Medical lots are often small and they repeat. Workholding that costs a day to build is expensive against 50 parts and cheap against 50 parts every quarter for four years.

What you can change: tell the supplier the annual quantity and the expected life of the part, not just this purchase order. A shop that knows the part repeats will invest in fixturing and price the repeat lots accordingly. A shop that thinks it is a one-off will not, and will quote the one-off price every time.

A worked way to use this

Before you send the next RFQ, go down the drawing and answer three questions.

Which tolerances are carrying a function, and which were inherited from a template?
Which surface treatments are required by the device file, and which are habit?
What is the realistic annual quantity, and does the supplier know it?

Buyers who answer those three before quoting usually find 10 to 20 percent without touching the material and without a regulatory change. Then send the drawing, and send the same drawing to every supplier so the quotes are actually comparable.

This post covers the drivers. The medical machining quote guide shows how they appear as lines on a quote and how to compare two quotes.

Frequently asked questions

Why is the same part twice the price from a medical supplier?

Usually the certificate and the records rather than the cutting. Traceable implant bar, a first article report, lot records and validated cleaning are real hours that a general shop does not quote because it does not do them.

Does the price per part drop much with quantity?

Setup and fixturing spread across the lot, so yes up to a point. Hand polishing, inspection per part and packaging do not spread at all, so a part dominated by those costs flattens out quickly.

Is it cheaper to loosen the tolerance or to change the material?

Loosening a tolerance you do not need is almost always the cheaper of the two, because material changes drag a regulatory file behind them. Check the tolerance stack before you touch the material.

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