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What Cleanroom Machining Actually Requires

September 21, 2026

Cleanroom machining is mostly a misnomer. Very little semiconductor hardware is cut inside a classified space. The part is machined in a normal shop, and what makes it a cleanroom part is everything that happens after the last chip falls.

That is the part buyers underquote and shops underprice.

The process chain, step by step

Deburring and edge treatment. A burr is a particle waiting for a vibration. On wafer handling hardware, edge quality is a functional spec, not a cosmetic one. This is hand work, it takes time and it is the step most often dropped when a shop is behind schedule.

Degreasing. Cutting oil, way lube and fingerprints all have to come off before any finishing step. Ultrasonic cleaning with the right chemistry and a controlled rinse is normal. Tap water rinse and shop air is not.

Finishing. Hard anodize, electropolish and passivation change the surface the process sees. They are almost always done outside the machine shop, which means the part travels, gets handled and comes back needing another clean.

Final cleaning. After finishing, not before. Anything done before the last handling step is decoration.

Drying and packing. Filtered air or a controlled oven, then double bagging with the inner bag sealed in a clean area. The outer bag is removed at the airlock and the inner bag goes in. That is the whole point of double bagging, and it only works if the shop understands why.

Documentation. Material certificate, dimensional report, finish certificate and a packing note that states what was done. Without the paper, the part is not qualified, whatever it measures.

What the classes mean

ISO 14644-1 defines air cleanliness classes by particle count per cubic metre. Class 5 allows dramatically fewer particles than Class 7, and each step down costs real money in air handling, gowning and discipline. The standard describes the room, not your part. See the ISO 14644-1 standard for the definitions.

Where buyers go wrong is copying a class number onto a drawing for a part that is cleaned and bagged in one place and unbagged in another. What you usually want to specify is the cleaning and packing procedure plus an acceptance test, not the class of a room your part passes through for twenty minutes.

What it does to the price

The cost sits in four places:

  • Hand deburring and edge work, per part, every part
  • Cleaning chemistry, consumables and the labour around them
  • Packing materials and the clean space to pack in
  • Inspection and paperwork, which grows with the number of reports you ask for

On a large frame the premium is a small percentage. On a small wafer handling part it can be more than the machining. That is not a shop trying it on. It is where the hours go.

How to specify it so the quote is real

State these five things and the quotes you get back become comparable:

  1. Where the part is used and what it touches
  2. The finish and which surfaces it applies to, with masking called out
  3. The cleaning level and the packing method, in words
  4. The certificates and reports you require
  5. The acceptance test, if you run one

Leave any of them out and each shop fills the gap with its own assumption. The cheapest quote is then simply the shop that assumed the least work, which is the one you do not want.

Sourcing this kind of part in Vietnam adds one more question, which is who does the finishing and how far the part has to travel to get there. That is covered in the buyer checklist for semiconductor parts.

Have a drawing with a cleanliness requirement on it? Send the RFQ and we will match it with shops that can describe their process, not just quote it.

Frequently asked questions

Does the part have to be machined inside a cleanroom?

Usually not. Most machined semiconductor hardware is cut in a normal shop, then cleaned, inspected and packed under controlled conditions. Machining inside a classified area is reserved for a narrow set of parts, and it is far more expensive.

What is a realistic cost premium?

It depends on size, material and finish, so treat any single number with suspicion. The premium is labour and consumables for deburring, cleaning and packing, plus inspection time. On small parts it can exceed the machining cost itself.

How do I specify cleanliness without over specifying?

Say what the part touches and where it goes, then state a packing level and an acceptance test you will actually run. A particle count you never measure only adds price. A clear handling and packing note changes how the part is made.

Need a quote for this part?

Send the drawing. We match you with up to 3 shops in Vietnam and reply within 24 business hours.

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More on process

All guides and the sourcing glossary.