The Ceramic RFQ Checklist: 10 Things to Send a Technical Ceramic Manufacturer

The 10-point checklist

Copy this into your own enquiry template.

1. Material grade — with impurity limits, not just a name

"Alumina" is not a specification. Write "Alumina, Al2O3 ≥ 99.7%, Na2O ≤ 0.05%, Fe2O3 ≤ 0.03%". If you do not know which grade you need, say what the part does and let the manufacturer recommend. Our purity guide explains what the numbers control.

2. A drawing or 3D model

PDF drawing, STEP file, or both. A photo and a description work for simple shapes, but anything with a tolerance needs geometry. If the part already exists as a physical sample, say so — reverse engineering is routine, and it is usually worth sending the sample.

3. Critical tolerances — marked as critical

This is the single highest-value item on the list. A drawing where every dimension is ±0.01 mm costs far more than the same part where three functional dimensions are tight and the rest are reference. Grinding time is the dominant cost in most ceramic parts, and grinding time follows tolerance.

4. Surface finish requirements, per face

Finish is specified per surface, not per part. A sealing face at Ra 0.2 µm and a mounting boss at Ra 3.2 µm belong on the same drawing. As with tolerance, over-specifying finish everywhere is the most common way to pay too much.

5. Quantities — first order and annual

Give both: the quantity you want now (which may be a prototype) and the annual volume you expect. Tooling amortisation and process setup are fixed costs, so the annual figure changes the unit price dramatically. A supplier who only sees a quantity of five will quote as if it is a one-off.

6. Operating environment

Temperature range, medium (plasma chemistry, acid, slurry, DI water, air), load type (static, impact, bending, thermal cycling), electrical duty and expected service life. This is the information that lets a supplier say "you actually need a different grade" — which is worth more than a fast quote.

7. Documentation requirements

State up front whether you need a certificate of analysis, a dimensional inspection report, material traceability, a first-article inspection report, or third-party testing. These are easy to build into the process at quotation and expensive to add after the parts are made.

8. Cleaning and packaging

Does the part go into a cleanroom? Is it vacuum-facing? Can it ship in standard foam-packed cartons, or does it need cleanroom-compatible double bagging with a defined cleaning route? Contamination introduced in packaging is indistinguishable from contamination generated by the part in service.

9. Delivery date and destination

Give the date you need the parts in hand, not the date you would like them shipped, and give the destination country and city. For export orders, Incoterms and any certification requirements (for example CE or RoHS declarations) should be stated at enquiry stage.

10. Target price or budget, if you have one

Many buyers withhold this. It is usually a mistake. If your target is far below what the part can be made for, better to find that out in an hour and discuss design changes than after a week of quoting. Suppliers routinely propose a cheaper route — a different grade, a relaxed tolerance, a revised feature — when they know the constraint.

A bad enquiry and a good one, side by side

Enquiry that will produce a slow, vague answer:

Hi, we need some ceramic insulator rings, around 80 mm diameter, quantity 100. Please quote.

Problems: no grade, no drawing, no thickness or tolerance, no application, no environment, no delivery, no documentation. Any answer would be a guess.

Same request, properly written:

We need 100 pcs of an insulating ring for an RF plasma chamber, annual volume approximately 400 pcs. Material: alumina, Al2O3 ≥ 99.7%, low alkali. Outside diameter 80.0 ±0.05 mm, inside diameter 60.0 ±0.05 mm, thickness 6.0 ±0.02 mm, flatness on both faces 20 µm, edges radiused. Surface finish Ra ≤ 0.8 µm on both faces. Environment: fluorine-based plasma, up to 250 °C, RF insulating duty. We need certificate of analysis per lot and a dimensional report on the first article. Cleanroom-compatible packaging required. Target delivery 6 weeks to Rotterdam. Please also advise if a different alumina grade would extend life in this chemistry.

The second enquiry is not much longer. It is quotable today, and it invites technical input rather than a number.

What to expect on lead time

Realistic figures for custom technical ceramic parts:

• Quotation: 1–2 working days for a complete enquiry. Same-day is achievable when the drawing is clear.
• First article, simple geometry in alumina: typically 3–5 weeks.
• First article, complex geometry or SiC/AlN: typically 5–8 weeks, longer if new tooling is needed.
• Repeat order, established part: typically 2–4 weeks.

Two things stretch these numbers: a drawing that changes after tooling has started, and documentation requirements added after production. Both are avoidable at the enquiry stage.

What you should get back

A good response to a complete enquiry includes:

1. A unit price with quantity breaks, and a clear statement of what is included.
2. A lead time in weeks from drawing approval, not from the date of the email.
3. Any technical comment — grade recommendation, manufacturability warnings, suggested tolerance relaxations.
4. Tooling or setup charges itemised separately, so you can see what a repeat order will cost.
5. A quotation validity period, which for technical ceramics usually reflects raw material price movement.

If you get none of that, you are probably talking to a trader rather than a factory.

Five questions worth asking a new ceramic supplier

• Do you press and sinter in-house, or only machine? A machine-only supplier cannot control density, grain size or purity, and cannot help you when a part fails.
• Where is grinding done? In-house diamond grinding means dimensional problems are caught before shipping, not after.
• Can I see a certificate of analysis on finished parts? Powder certification is not enough; contamination can enter during milling and firing.
• Who is my technical contact? You want an engineer, not a sales inbox.
• What happens when a part is out of tolerance? The answer tells you how the relationship will go.

Send us your enquiry

Dolphin Advanced Ceramic manufactures high-purity alumina, aluminum nitride, zirconia and silicon carbide components in Zibo, Shandong, with powder formulation, pressing, sintering, diamond grinding and metallization all in-house. We reply to complete enquiries within 24 hours, Monday to Saturday.

Use the RFQ form, email dolphintec@aliyun.com, or send a drawing directly on WhatsApp to +86 133 8643 4414. Drawings and NDAs are handled confidentially.

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