Author: John Smith, Applications Engineer at Shanyo, 6 years on snap dome programs for consumer and automotive customers.
Last spring we shipped a 420,000-piece run of 12 mm round domes to a California startup launching a smart-thermostat line. The first two samples passed every check. By the third mass-production lot, their QC rejected 11% because actuation force had drifted from 280 g to 330 g. Their buyer came back frustrated - the previous supplier had quoted ±15% tolerance on a datasheet, then silently shipped ±30% parts.
That story is the reason I wrote this checklist. If you are buying metal dome switches for the first (or fifth) time from China, the spec sheet is where deals are won or lost. This guide distils the RFQ clauses, factory-audit questions and acceptance tests we actually run at Shanyo on 60 million domes a year - so you can specify the part once and not argue about it at incoming inspection.
1. Pin down what you are buying: bare domes, arrays, or die-cut modules
Buyers new to the category often confuse three products that look identical in a photo but carry very different price and risk profiles.
- Bare snap domes are loose stamped discs, 0.08–0.15 mm thick, packed on tape or in trays. You (or your PCB assembler) must pick-and-place them. Cheapest per piece, but assembly yield is on you.
- Dome sheet arrays are multiple domes pre-laminated onto a PET or PI carrier with adhesive backing. The operator peels the liner and stamps the whole array down in one shot. This is what 80% of remote-control, TV and smart-home buyers actually want.
- Die-cut modules add a gasket, spacer layer, or graphic overlay on top. Used in sealed keypads, medical devices and outdoor controls.
If a supplier quotes you "$0.02 per dome" but your line expects an array, you will quietly add $0.12 of labour per keypad. State the form factor in your very first email.
2. The eight specifications that must be on your RFQ
A Chinese sales engineer can quote you in ten minutes if you hand them these eight numbers. If they come back with a price but skip two or three, treat that as a yellow flag.
Material. SUS301 (full hard) is the default for 90% of designs. SUS304 is used when you need better corrosion resistance but accept a softer click. Reputable mills issue a material test certificate - ask for it.
Actuation force and tolerance. Tell them the target force in grams (typical 100 g–600 g) and the tolerance you can live with. Consumer electronics usually accept ±15%; automotive and medical demand ±10% or tighter. On our automotive line we hold ±10 g, measured on a probe stand at 1 mm/s.
Click ratio. This is (peak force − return force) ÷ peak force. Below 30% the key feels mushy; above 60% it feels harsh and fatiguing. For TV remotes we recommend 40–50%; for steering-wheel switches, 35–45%.
Lifespan. Cheap domes die at 100,000 actuations; standard consumer-grade runs 500,000; automotive-grade is 1,000,000–3,000,000 cycles. The published number must come with a test report, not a datasheet promise.
Dome geometry. Round (3 mm to 20 mm), triangular, oval, four-leaf clover. Size drives the PCB land pattern - lock it early.
Plating and contact finish. Unplated SUS is fine for most consumer uses. Gold plating on the contact spot is for low-signal medical or aerospace work. Nickel underplate with a tin flash is the automotive workhorse. Ask specifically for salt-spray hours - our marine-grade plating runs 500 hours neutral salt spray without red rust.
Operating temperature. -20 °C to +70 °C is consumer grade. Under-hood automotive asks for -40 °C to +85 °C. If your product sits in a car cup holder in a Phoenix summer, specify -40 °C cold-curve testing.
Mounting. Adhesive backing (3M 467 or equivalent), PET carrier, or direct integration onto an FPC flexible circuit. Each changes price and assembly process.
Author: John Smith, Applications Engineer at Shanyo, 6 years on snap dome programs for consumer and automotive customers.
Last spring we shipped a 420,000-piece run of 12 mm round domes to a California startup launching a smart-thermostat line. The first two samples passed every check. By the third mass-production lot, their QC rejected 11% because actuation force had drifted from 280 g to 330 g. Their buyer came back frustrated - the previous supplier had quoted ±15% tolerance on a datasheet, then silently shipped ±30% parts.
That story is the reason I wrote this checklist. If you are buying metal dome switches for the first (or fifth) time from China, the spec sheet is where deals are won or lost. This guide distils the RFQ clauses, factory-audit questions and acceptance tests we actually run at Shanyo on 60 million domes a year - so you can specify the part once and not argue about it at incoming inspection.
1. Pin down what you are buying: bare domes, arrays, or die-cut modules
Buyers new to the category often confuse three products that look identical in a photo but carry very different price and risk profiles.
- Bare snap domes are loose stamped discs, 0.08–0.15 mm thick, packed on tape or in trays. You (or your PCB assembler) must pick-and-place them. Cheapest per piece, but assembly yield is on you.
- Dome sheet arrays are multiple domes pre-laminated onto a PET or PI carrier with adhesive backing. The operator peels the liner and stamps the whole array down in one shot. This is what 80% of remote-control, TV and smart-home buyers actually want.
- Die-cut modules add a gasket, spacer layer, or graphic overlay on top. Used in sealed keypads, medical devices and outdoor controls.
If a supplier quotes you "$0.02 per dome" but your line expects an array, you will quietly add $0.12 of labour per keypad. State the form factor in your very first email.
2. The eight specifications that must be on your RFQ
A Chinese sales engineer can quote you in ten minutes if you hand them these eight numbers. If they come back with a price but skip two or three, treat that as a yellow flag.
Material. SUS301 (full hard) is the default for 90% of designs. SUS304 is used when you need better corrosion resistance but accept a softer click. Reputable mills issue a material test certificate - ask for it.
Actuation force and tolerance. Tell them the target force in grams (typical 100 g–600 g) and the tolerance you can live with. Consumer electronics usually accept ±15%; automotive and medical demand ±10% or tighter. On our automotive line we hold ±10 g, measured on a probe stand at 1 mm/s.
Click ratio. This is (peak force − return force) ÷ peak force. Below 30% the key feels mushy; above 60% it feels harsh and fatiguing. For TV remotes we recommend 40–50%; for steering-wheel switches, 35–45%.
Lifespan. Cheap domes die at 100,000 actuations; standard consumer-grade runs 500,000; automotive-grade is 1,000,000–3,000,000 cycles. The published number must come with a test report, not a datasheet promise.
Dome geometry. Round (3 mm to 20 mm), triangular, oval, four-leaf clover. Size drives the PCB land pattern - lock it early.
Plating and contact finish. Unplated SUS is fine for most consumer uses. Gold plating on the contact spot is for low-signal medical or aerospace work. Nickel underplate with a tin flash is the automotive workhorse. Ask specifically for salt-spray hours - our marine-grade plating runs 500 hours neutral salt spray without red rust.
Operating temperature. -20 °C to +70 °C is consumer grade. Under-hood automotive asks for -40 °C to +85 °C. If your product sits in a car cup holder in a Phoenix summer, specify -40 °C cold-curve testing.
Mounting. Adhesive backing (3M 467 or equivalent), PET carrier, or direct integration onto an FPC flexible circuit. Each changes price and assembly process.
3. MOQ, sampling and lead time: what "factory price" really means
A common frustration for first-time buyers: the website advertises "factory direct" but the MOQ is 50,000 pieces and the quote expires in 90 days. Realistic numbers from our shop floor:
| Item | Typical range | Shanyo standard |
|---|---|---|
| Sample lead time | 5–10 working days | 48 hours for standard geometries |
| Sample cost | $30–$100 per part | Free for standard shapes, freight collected |
| Mass-production MOQ | 10,000–50,000 pcs | 5,000 pcs for standard domes |
| Mass-production lead time | 15–30 days | 7–15 days, 60M pcs/year capacity |
| Tooling cost | $200–$800 per custom shape | Waived on repeat orders over 200k pcs |
If a supplier quotes lead times under 7 days for a custom dome with no tooling charge, ask how they will stamp a new geometry without a die. The honest answer is "we use an existing blank and edit the tool" - fine for prototyping, not for a 500k-piece program.
4. Certifications that separate factories from trading companies
Anyone can print ISO9001 on a website. The certifications that matter depend on your market.
- Consumer electronics (remotes, wearables, gamepads): ISO9001 + RoHS + REACH. Ask for the material test reports from the latest lot, not just the certificate.
- Automotive: IATF 16949. More importantly, ask whether they can ship a PPAP package (PSW, PFMEA, control plan, force-curve SPC data). We ship PPAP on every automotive metal dome order; trading houses usually cannot.
- Medical: ISO 13485 or at minimum a Class 100k cleanroom lamination line. Our cleanroom came online this year specifically for medical-dome-array programs.
- Marine / outdoor: 500-hour salt-spray report, UV exposure data if the dome sits under a clear overlay.
One audit trick: ask for a short video of the force-curve tester running on your part. Real factories have the equipment on the floor; traders will promise it "tomorrow".
5. Seven red flags in supplier communications
After 22 years in this industry, patterns repeat. Walk away or push back hard when you see any of these:
- No force-curve data on the technical drawing. A snap dome without a force-displacement curve is a paperweight you are betting a product on.
- "Tolerance ±20%" offered casually. On a 280 g dome, ±20% means the user feels 224 g on one key and 336 g on the next. That is a warranty return waiting to happen.
- They cannot name their steel mill. SUS301 from a Tier-1 Japanese or Korean mill behaves differently from unknown Chinese strip.
- No second production site. We run lines in China and Vietnam. If your supplier is single-site and a port strike or power outage hits, your launch date floats with it.
- Refusal to put lifetime testing in writing. "1 million cycles typical" on a datasheet is not the same as "we will test 3 batches at 1M cycles and send the report".
- No English-speaking engineer on the call. You will end up negotiating critical tolerance through a salesperson who interprets drawings as a hobby.
- Pricing 30–40% below market. At dome volumes, the steel and stamping-die cost floor is real. A quote well below it usually means swapped material or skipped plating.
6. How Shanyo stacks up on this checklist
We built this guide the way we run our own shop. When you send an RFQ to Shanyo, here is what comes back within 24 hours:
- A force-curve graph on your exact geometry, measured on our probe stand - not a guess.
- A tolerance table with three options: ±15% consumer, ±10% industrial, ±5% automotive.
- The material test certificate for the steel lot we would use.
- Sample lead time in writing: 48 hours for standard round domes, 5 working days for custom shapes.
- Confirmation of IATF 16949, ISO 9001 and RoHS, with the actual certificate PDFs attached.
We are not the cheapest quote you will get. We are the quote where incoming inspection does not become a weekly fire drill.
The bottom line
Buying metal domes from China is not a sourcing problem, it is a specification problem. Spend the first hour of your next RFQ locking material, force, click ratio, lifespan, plating and tolerance. Then ask the supplier to prove each one with data, not marketing words. Do that and the 420,000-piece thermostat story at the top of this article will not be yours.
Ready to start your next program? Send us your drawing, a sample part, or even just a sketch of the keypad. Our engineers will send back a force-curve proposal and a free sample within 48 hours - no minimum order for standard shapes.
John Smith is an applications engineer at Qingdao Shanyo Precision Electronic Technology Co., Ltd., a metal dome manufacturer in Qingdao, China, shipping 60 million domes a year to consumer, automotive and medical customers worldwide.
3. MOQ, sampling and lead time: what "factory price" really means
A common frustration for first-time buyers: the website advertises "factory direct" but the MOQ is 50,000 pieces and the quote expires in 90 days. Realistic numbers from our shop floor:
| Item | Typical range | Shanyo standard |
|---|---|---|
| Sample lead time | 5–10 working days | 48 hours for standard geometries |
| Sample cost | $30–$100 per part | Free for standard shapes, freight collected |
| Mass-production MOQ | 10,000–50,000 pcs | 5,000 pcs for standard domes |
| Mass-production lead time | 15–30 days | 7–15 days, 60M pcs/year capacity |
| Tooling cost | $200–$800 per custom shape | Waived on repeat orders over 200k pcs |
If a supplier quotes lead times under 7 days for a custom dome with no tooling charge, ask how they will stamp a new geometry without a die. The honest answer is "we use an existing blank and edit the tool" - fine for prototyping, not for a 500k-piece program.
4. Certifications that separate factories from trading companies
Anyone can print ISO9001 on a website. The certifications that matter depend on your market.
- Consumer electronics (remotes, wearables, gamepads): ISO9001 + RoHS + REACH. Ask for the material test reports from the latest lot, not just the certificate.
- Automotive: IATF 16949. More importantly, ask whether they can ship a PPAP package (PSW, PFMEA, control plan, force-curve SPC data). We ship PPAP on every automotive metal dome order; trading houses usually cannot.
- Medical: ISO 13485 or at minimum a Class 100k cleanroom lamination line. Our cleanroom came online this year specifically for medical-dome-array programs.
- Marine / outdoor: 500-hour salt-spray report, UV exposure data if the dome sits under a clear overlay.
One audit trick: ask for a short video of the force-curve tester running on your part. Real factories have the equipment on the floor; traders will promise it "tomorrow".
5. Seven red flags in supplier communications
After 22 years in this industry, patterns repeat. Walk away or push back hard when you see any of these:
- No force-curve data on the technical drawing. A snap dome without a force-displacement curve is a paperweight you are betting a product on.
- "Tolerance ±20%" offered casually. On a 280 g dome, ±20% means the user feels 224 g on one key and 336 g on the next. That is a warranty return waiting to happen.
- They cannot name their steel mill. SUS301 from a Tier-1 Japanese or Korean mill behaves differently from unknown Chinese strip.
- No second production site. We run lines in China and Vietnam. If your supplier is single-site and a port strike or power outage hits, your launch date floats with it.
- Refusal to put lifetime testing in writing. "1 million cycles typical" on a datasheet is not the same as "we will test 3 batches at 1M cycles and send the report".
- No English-speaking engineer on the call. You will end up negotiating critical tolerance through a salesperson who interprets drawings as a hobby.
- Pricing 30–40% below market. At dome volumes, the steel and stamping-die cost floor is real. A quote well below it usually means swapped material or skipped plating.
6. How Shanyo stacks up on this checklist
We built this guide the way we run our own shop. When you send an RFQ to Shanyo, here is what comes back within 24 hours:
- A force-curve graph on your exact geometry, measured on our probe stand - not a guess.
- A tolerance table with three options: ±15% consumer, ±10% industrial, ±5% automotive.
- The material test certificate for the steel lot we would use.
- Sample lead time in writing: 48 hours for standard round domes, 5 working days for custom shapes.
- Confirmation of IATF 16949, ISO 9001 and RoHS, with the actual certificate PDFs attached.
We are not the cheapest quote you will get. We are the quote where incoming inspection does not become a weekly fire drill.
The bottom line
Buying metal domes from China is not a sourcing problem, it is a specification problem. Spend the first hour of your next RFQ locking material, force, click ratio, lifespan, plating and tolerance. Then ask the supplier to prove each one with data, not marketing words. Do that and the 420,000-piece thermostat story at the top of this article will not be yours.
Ready to start your next program? Send us your drawing, a sample part, or even just a sketch of the keypad. Our engineers will send back a force-curve proposal and a free sample within 48 hours - no minimum order for standard shapes.
John Smith is an applications engineer at Qingdao Shanyo Precision Electronic Technology Co., Ltd., a metal dome manufacturer in Qingdao, China, shipping 60 million domes a year to consumer, automotive and medical customers worldwide.
