How we hold every build to the unit you signed
Quality starts in the schematic and ends with a batch that matches your golden sample. Our engineers design for test, the Shenzhen factory runs the inspection, and each batch is held to the unit you signed. Engineered in San Francisco. Prototype builds, DFM and mass production in our own factory in Shenzhen.
What holds production to the design?
A signed reference unit and a written record. After DVT and PVT you sign the golden sample, and the record lists the design revision, the BOM, the firmware release, the measured values and the cosmetic limits. Every production batch is compared with it, and any drift goes to an engineer, as the questions below explain.
The cosmetic limits are judged under set light at a set distance, so two inspectors reach the same answer. Both parties keep the sign-off record. When the design changes after sign-off, the new build is measured against the old reference and a new golden sample is signed. See how a golden sample is defined and signed.
How does quality change from a demo build to production?
The checks grow with the stakes. A demo build gets inspection and a functional check so it works on the day you show it. EVT and DVT add test results and a validation report. PVT runs on production fixtures. Production batches are compared with the golden sample, and their inspection and test results come to you.
This is why the test plan starts during the DFM review, not at the end of the line. Test points, fixture access and the test images for the line are designed while the board can still change.
Certificates held by the Shenzhen factory, and one standard
| Certificate | Scope | What it means for your product |
|---|---|---|
| ISO 9001 | Quality management | The base of the quality system. It governs process control, traceability and corrective action across the factory, from the first review of your files to shipment. |
| ISO 13485 | Medical device quality | Covers design, production and traceability for medical devices. The factory builds medical devices, and exoskeletons and rehab devices, under it. The FDA path for a medical product runs with your regulatory team. |
| IATF 16949 | Automotive quality | Adds defect prevention and the reduction of variation to ISO 9001. Automotive and EV parts are built under it. |
| AS9100 | Aerospace quality | Adds traceability, risk management and configuration control. Aerospace and drone parts are built under it. |
| ISO 14001 | Environmental management | Controls waste, emissions and resource use in the factory. |
| IPC-A-610 Class 2 and 3 | Assembly workmanship (a standard, not a certificate) | Operators and inspectors are trained to both classes. Class 2 fits most commercial products. Class 3 is for products where a field failure costs most, and boards are built to it on request. |
The quality process, stage by stage
1. Design for quality. Our engineers run a DFM review that covers assembly and test as well as manufacture. Parts availability and alternates are checked before the schematic is drawn. Firmware engineers review the schematic before layout starts. A second engineer checks every schematic and layout (power tree, footprints, connector pinouts, parts against the BOM) before delivery. See DFM services.
2. Supplier quality. Parts come from a network of 350 audited suppliers. A supplier quality team qualifies and audits them, keeps a preferred vendor list and reviews their performance.
3. Incoming quality control. No part enters a line without a check. The IQC team uses LCR meters, XRF analyzers for RoHS and digital microscopes. Critical parts are checked one by one; others are sampled to AQL.
4. In-process control. AOI runs after paste printing and after reflow. X-ray checks BGA and other hidden joints on the advanced route. Assembly steps that need clean conditions run in the Shenzhen factory's ISO 7 clean room. First-article inspection runs on every new production run, and SPC charts track process stability as it runs.
5. Final quality assurance. In-circuit and functional tests run on fixtures built for your product, then a final visual check against the cosmetic limits. Packaging and labels are checked for safe transit.
6. Traceability. The MES links each serial number to its parts, process steps and test results. Firmware test results are kept per unit, by serial number. That record drives root-cause work when something fails.
What do you receive at each stage gate?
A written report and something you can test. The DFM review ends with a findings report and changed files. EVT and DVT deliver units with test results and a validation report. PVT delivers units with the test plan and the fixture definitions. Each production batch comes with inspection and test results against the golden sample.
Test and validation lab
The lab runs the tests below on your units and writes the results into the stage report.
| Test | What it finds |
|---|---|
| AOI | Missing parts, wrong polarity and solder bridges |
| X-ray (2D and 3D) | Faults in joints the eye cannot see, such as BGA and QFN, on the advanced route |
| In-circuit test | Shorts, opens and wrong part values, on a bed-of-nails fixture |
| Functional test | Function against the specification, on fixtures built for your product; 30+ ICT/FCT test stations run in the factory |
| Environmental stress screening | Latent defects, brought out by thermal cycling and vibration |
| RF test | Radio performance; shielded setups check and calibrate Wi-Fi, Bluetooth, cellular and GPS |
| Gage R&R | Whether the test equipment measures what it should |
| Failure analysis | Root cause, by cross-sectioning, microscopes and solderability tests |
Who does the quality work?
Engineers and inspectors, each with a clear role. Design engineers build testability into the schematic and layout. Test engineers write the test plan and the test images for the line. Quality engineers run incoming, in-process and final inspection, and they compare each batch with the golden sample.
Supplier quality engineers audit the parts network, and operators and inspectors are trained to IPC-A-610. The same people who signed off your PVT build look at your production data, so a problem is read by someone who knows how the product should behave.
Quality controls by type of work
PCB and PCBA. 3D solder paste inspection checks volume, height and alignment before placement. AOI runs after reflow on every board, and X-ray checks BGA, QFN and hidden-joint packages on the advanced route. In-circuit test finds wrong values, shorts and opens. First-article inspection compares the first production unit with the design, and SPC tracks reflow profiles, paste volume and placement.
Custom parts. A CMM measures critical dimensions to ±0.005 mm. Cavity pressure monitoring confirms the scientific molding settings. Each batch comes with material certificates and test reports, and a profilometer measures surface roughness. Cpk studies on critical dimensions come before production release, and PPAP documentation covers automotive and other high-reliability parts.
NPI and production. Each stage gate has entry and exit criteria and ends with a written report. The DFM review is repeated before DVT and before tooling. Production test fixtures are built before PVT, and at PVT the ICT/FCT stations run the production test firmware. After golden sample sign-off, each batch is compared with it. Engineering change orders carry an impact assessment, and quarterly yield reviews, 8D corrective actions and Pareto analysis drive improvement.
Production units ship with debug ports locked. Read how a build moves into volume in transfer to production, or see the testing and inspection service.
Quality in four facts
IPC-A-610 Class 3 is the workmanship standard assemblies are built and inspected to on request. ISO 9001 is the certified system behind process control, traceability and corrective action. SPI and AOI run on every board: paste inspection before reflow, optical inspection after it. The free engineering review means an engineer checks the exact files and revision you submitted before any payment.
Questions about quality
Which certificates does the Shenzhen factory hold?
ISO 9001, ISO 13485, IATF 16949, AS9100 and ISO 14001. They cover medical devices and rehab devices under ISO 13485, automotive and EV parts under IATF 16949, and aerospace and drone parts under AS9100. Assemblies are built to IPC-A-610 Class 3 on request.
What happens when a batch does not match the golden sample?
The batch stops at the comparison. An engineer reviews the drift, finds the cause in the process or the parts, and fixes it before the next batch runs. You receive the inspection and test results for every batch, so you see what was found and what changed.
Can I audit the factory?
Yes. Ask for the quality manual, or arrange a remote or in-person audit with an engineer. The factory tour shows what each station does, so you can plan the audit around the stations your product uses. We sign your NDA before the first call.
Do you support a medical certification path?
Yes, as a path. The factory builds medical devices under ISO 13485, and DVT delivers units for the certification path with a validation report. Your regulatory team runs the FDA path. We make no claim about approval; that decision belongs to the regulator.
Talk to us about your quality plan
Send your test requirements or a product specification. An engineer replies with the inspection and test plan that fits it. See medical device engineering and automotive engineering.