Guides / Process

Wafer Handling Parts: Why Edge Quality Beats Tolerance

September 21, 2026

On most machined parts, a burr is a cosmetic problem. On a wafer handling part it is a particle source sitting directly above the product. That single difference reorders everything about how these parts are quoted, made and inspected.

What actually matters

Edge and surface condition. Every edge that faces the wafer, and every surface that gas flows across, has to be free of loose material. This is hand and process work, it is slow and it is the first thing a shop under schedule pressure cuts.

Stiffness and flatness under load. A blade deflects with the wafer on it. The number that matters is the position of the wafer when loaded, not the flatness of the blade on a granite plate.

Thermal behaviour. Parts that move hot wafers change dimension. Aluminum moves more than ceramic. If the handoff position drifts with temperature, the material choice is the cause.

Static. Insulating materials hold charge, and charge attracts particles and can damage devices. Where that matters, static dissipative material or a conductive coating is specified, which is covered in ESD materials and coatings.

Material choices in plain terms

Material	Why it is chosen	What it costs you
Aluminum 6061 with hard coat	Light, cheap, fast, easy to modify	Softer, wears, moves with temperature
Stainless 316L	Stiff, corrosion resistant, cleans well	Heavy for a moving arm
PEEK and static dissipative grades	Non marking, insulating or ESD safe	Moves with heat and moisture, needs careful fixturing
Alumina and silicon carbide	Stiff, stable, low particle	Ground not milled, long lead time, few suppliers locally

What to put on the drawing

The edge condition, with a size and a method, plus a sample requirement on the first article
Surface finish with the surfaces named, not a blanket note
Flatness with the datum scheme and the condition, free state or constrained
Handling and packing, including whether the part may be touched with bare gloves at any point
Cleaning level and the certificate you require

The specification that fails most often is the one that says nothing about edges and then rejects the part for particles. Say what you want measured, and how.

Inspection that means something

A CMM report proves the geometry. It says nothing about particles. For handling hardware the useful additions are a visual inspection at a stated magnification and light level, a tape or wipe test where your process uses one and a photograph of the packed part so you can see how it left. None of that is exotic, and all of it has to be agreed before the order, because each item costs time.

If you are sourcing handling hardware and want it quoted by shops that understand edge work rather than just hole positions, send the RFQ with the edge and cleanliness requirements written down.

Frequently asked questions

Aluminum, ceramic or silicon carbide for a blade?

Aluminum for cost, weight and general handling. Ceramic and silicon carbide where stiffness, temperature or particle performance justify the price and the longer lead time. A machined aluminum blade with a hard coat covers a large share of handling hardware.

What flatness is realistic on a long thin blade?

It depends on thickness, length and how the part is fixtured and stress relieved. A long thin part will move when it is unclamped, so the achievable number is a conversation with the shop, not a value copied from another drawing.

How do I stop a supplier from polishing away my edge break?

Specify the edge condition explicitly, with a size and a method and require a sample for approval on the first article. Words like smooth and deburred mean different things in different shops.

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