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Two visitors walking away from the camera down the centre aisle of an assembly hall, rows of SMT machines and component reels on both sides

Resources · engineering note · visiting China

Your first factory
visit in Shenzhen.

What two days should cover, the records worth asking for, and what to look at that a factory cannot stage for you.

Book a factory visit China visit & factory tours
Sites in two days
2
Realistic in Bao'an; Dongguan means the traffic sets the agenda
Notice a factory needs
48h
Book about a week ahead; the written report follows in 24 to 48 hours
An audited man-day costs
$220+
A quality-system audit runs to about $458 per man-day
Fly into
SZX
Hong Kong adds a border crossing that can cost a morning

01Scope of the trip

Two days buys three things. It does not buy a qualification.

1 or 2 sites1 working sessionQualification continues after you fly

Plan the visit as the middle of a supplier qualification, not the end of it.

What two days gives you, and what it cannot
ItemWhat two days gives youWhat it cannot
Production sitesOne or two real sites, walked end to endA complete capacity picture
Process routeAn interrogation of how the route is controlledA supplier qualification
Your specificationA working session with the engineers who build itA signed-off design review

Scroll the table sideways

Three long rows of identical placement machines seen from a raised viewpoint on a pale factory floor
Fig. 01You are there to read the process, not to duplicate a paid audit.
A wide assembly hall with machine lines on the left, a magnifier workstation behind glass and carts of parts in the centre
Fig. 02An auditor photographs this. You are there to interpret it.
An empty industrial hall with a teal guide line running to a closed roller door and a bare concrete floor
Fig. 03An empty hall is not evidence. Ask what is running today, and why.

Schedule the way inspectors do: 48 hours' notice to the factory, booked about a week ahead.

02The two-day itinerary

A two-day shape that fits Bao'an.

Day 1 · one siteDay 2 · one siteWrap-up before the airport

One site per half-day, plus travel. Two districts and a working session in one afternoon is a traffic problem.

A sample two-day itinerary
WhenWhat happensWhy it is there
Day 1, 09:00Site one: incoming goods, SMT, testStart at the front of the material flow
Day 1, 13:30Line walk with the process engineerAsk the questions on the floor
Day 1, 16:00Working session on your specificationThe engineers who will build it
Day 2, 09:00Site two: the alternative process routeCompare two answers to one question
Day 2, 13:30Records review: calibration, SPC, CAPARead the documents, not the wall
Day 2, 16:00Wrap-up and the assessment scopeAgree what arrives after you fly

Scroll the table sideways

An empty service corridor with pipework overhead, pale walls and a teal line running down the sealed floor to a closed door
Fig. 04Travel time is real time: Bao'an to Dongguan is one to two hours on paper.
Two people at a white table reading a dimensioned drawing, one holding a pen over the sheet
Fig. 05The afternoon session is where the visit earns its cost. Bring the open decision.
Two people in dark work jackets reading a printed sheet over a bench with a machined housing and a wrench
Fig. 06Close the day on paper: what was agreed, who owns it, and by when.

03Before you fly

Send the record request list in advance.

CalibrationSPCCAPAFirst articleScope statement

Records pulled in advance are evidence. Records hunted while you wait are a performance.

A clipboard holding a blank ruled grid with empty tick boxes, a rolled drawing, a black pen and a green clip beside it
Fig. 07Send the list, then read the answers against the documents in the room.
01 The core four Calibration records for every gauge, SPC data for three months, CAPA closures for two quarters, first-article reports.
02 Add these too Incoming inspection for a month, the subcontracted-process list with names, reflow profile records, AOI and SPI program revisions.
03 Ask for scope, not a picture The certificate with its scope statement and site address, not an image of a certificate. Verification is a step, not a favour.
04 Read the scope against the site A certificate is issued per legal entity and per scope. A different address does not cover the line in front of you.
05 Ask who signs the declaration Get the name on the visit — the same anchor you would check from your desk.
A closed grey notebook with a fountain pen and a brass rule lying beside it on a white surface
Fig. 08Bring your own pack: drawing, BOM, acceptance class, volumes, target market.
A dimensioned drawing, a populated green circuit board, a sealed bag of fasteners and a dark ring binder laid out on a pale bench
Fig. 09The records you asked for should be waiting on the table, not fetched while you sit.
A dimensioned engineering drawing on a pale sheet with a mechanical pencil and a pair of dividers beside it
Fig. 10Your own drawing, marked up on site, is worth more than a photograph of a machine.

04What cannot be staged

What a factory cannot stage for you.

Line balanceWIP ageingESDCalibrationAOI and X-ray

Anything on a wall is a claim. Anything in a binder with a date, a signature and a number is evidence.

What to look at, what to ask for, and what it tells you
What you look atWhat to ask forWhat it actually tells you
Line balanceHow many lines are running today, with a product on themRunning count is capacity; installed count is spending
WIP ageingThe route card on the oldest unit on the floorQueues build where the process is not controlled
ESD disciplineThe wrist-strap and heel-strap test log, with datesA daily routine, not a poster
CalibrationThe sticker, then the certificate behind itFive minutes is a process; an hour is a folder
AOI and X-rayThe program revision, its owner, and the reaction to an excursionA named owner is control

Scroll the table sideways

Rows of component reels feeding a line of placement machines receding down a bright assembly hall
Fig. 11Installed machines are easy to show. Ask how many are running, with what on them.
A green production panel on a conveyor entering a placement machine, with a reflow oven and two operators in the background
Fig. 12The oldest unit on the floor dates the queue better than any dashboard.
Two hands measuring a machined part with a digital caliper above a blank inspection checklist, a bagged sample and a white glove
Fig. 13The sticker first, then the certificate behind it. Time how long it takes to arrive.
A gloved hand holding a polished cross-section of a multilayer board under magnification, the plated barrel and copper layers in focus
Fig. 14Cross-sections are how a plated barrel is judged, and they take a coupon and a laboratory.

IPC-A-610J section 1.1 excludes cross-sectional and X-ray criteria. BGA void acceptance points to IPC-7095 and your own specification.

05Ask to see

Ask to see, not to be told.

SPC chartCAPA closureFirst articleMES walk-through

Five records separate a working system from a well-kept folder.

A fan of blank checklist sheets with empty tick boxes beside a pen, reading glasses and a small green circuit board in a tray
Fig. 15Read one record end to end. A sample that stops at "action taken" is not closed.
01 The SPC chart, with its limits Ask what happened at the last out-of-control point. A chart with no excursion is a chart nobody uses.
02 A CAPA record, read end to end Non-conformance, root cause, corrective action, and the verification that the action worked.
03 A first-article report with numbers Check which inspection class is printed on it, and whether that class matches your purchase order.
04 An MES walk-through Pick a serial number, follow it back to the reflow profile and the material lot, then forward to the box.
Two hands in white sleeves working on a green circuit board with tweezers under a magnifier lamp, six connector samples laid out below
Fig. 16Ask which class the first article was inspected to, and whether it matches your PO.
The locking bars and hinges of a closed container door with a teal seal through the handle and a document pouch
Fig. 17Traceability that stops at the SMT line is a software purchase, not a practice.
Two machined metal fittings and a drilled block on a pale bench above two blank sheets of paper and a pen
Fig. 18Numbers on the report, not ticks in the boxes. Ask to see the measured values.

06On the floor

Questions that produce answers.

Running linesAOI ownerMinimum componentFirst-pass yieldSubcontracting

Five questions, and what a real answer sounds like.

Q1 How many lines are running today? Not installed — running, with a product on them.
Q2 Who owns the AOI program revision? A revision number and a named owner. "The machine does it" means nobody does.
Q3 What is the minimum component, on which machine? Capability belongs to a machine and a nozzle set, not to the building.
Q4 What was last month's first-pass yield? Ask to see the source, not the summary. Published network figures reach 99.7%.
Q5 Which steps do you subcontract, and to whom? The answer defines your real supply chain and your real risk surface.
A test rack of finished TFT and OLED display modules in a bright inspection room, every screen lit to the same flat grey field
Fig. 19A test station in use looks different from a test station on a tour.
A production panel of twenty identical green circuit boards held in a pale inspection fixture
Fig. 20Minimum component size belongs to a machine and a nozzle set.
A magnified cross-section of a multilayer board showing alternating copper and dielectric layers and a plated through-hole barrel
Fig. 21What AOI cannot see is the reason a cross-section ends up in the report.

07The certificate

The certificate on the wall is not the answer.

12 / 24 list ISO 900115 / 24 RoHS15 / 24 CE2 list none

ISO 9001 certifies a management system. It contains no product parameter and certifies no output.

Two people at a bench under a lamp, one holding a board up to the light while the other writes on a drawing, calipers and tools laid out
Fig. 22Watch the system produce things: minutes, findings, non-conformance records, closure evidence.
01 What it certifies Document control, internal audit, management review, corrective action, continual improvement.
02 The honest sentence Holds an ISO 9001 quality management system certification — not a claim that the parts are good.
03 Three questions it cannot answer When was the last internal audit, who ran it, and what did it find? Then the last management review.
04 Counterfeits are a live probability A 2019 Business Horizons study, from interviews with 40 senior quality managers, found fake ISO 9001 certificates widespread in China.
A microscope objective, a sealed bag of teal desiccant beads with a blank label, and a plain white box on a pale bench
Fig. 23A scope that names another address does not cover the line in front of you.
A dimensioned technical drawing on a white sheet with a black pencil and a pair of dividers beside it
Fig. 24Certification names and standard codes are what you verify — never a holder name or a number.
Four identical green circuit boards standing in a black tray beside a small hinged enclosure, a white box and a blank tag
Fig. 25The visit's job is to check the system produces records, not to admire the frame.

Of the 24 partner sites, 12 list ISO 9001 among their certifications and 15 list RoHS, measured on 13 September 2026.

The trading company holds no citable certificate of its own, and no holder name or certificate number appears on this site.

08Reading the report

How to read an inspection report.

General level IICritical 0Major 2.5Minor 4.0

AQL decides the sample size. The checklist decides what counts as a defect. You need both.

General inspection level II — sample size and accept / reject
Lot sizeSampleAQL 2.5AQL 4.0
151–280322 / 33 / 4
281–500503 / 45 / 6
501–1,200805 / 67 / 8
1,201–3,2001257 / 810 / 11
3,201–10,00020010 / 1114 / 15

Scroll the table sideways

01 Read the reading A lot of 2,000 draws 125 pieces; at AQL 2.5, seven defectives pass and eight fail.
02 Defect classes Critical zero, major 2.5, minor 4.0 by default. Electronics and safety-related categories should be tightened to 1.0.
03 The report is a deliverable Standard 24 to 48 hours, expedited to four. Plan the release of the balance against it.
04 Who pays the inspector The buyer pays the inspection company directly. That independence is the point of the report.
Three open power supplies standing in front of three open cartons with a clipboard and a pair of white gloves
Fig. 26A report that stops at "pass" is a summary. The measurements are the report.
A test bench with an oscilloscope, a bench power supply with coloured terminals and a small board on a dark mat under a lamp
Fig. 27Functional test is defined by your specification, not by the inspector's judgement.
A dimensioned drawing squared to the frame with a digital caliper, a set square and three machined sample parts
Fig. 28The checklist defines defects. Without it, the AQL number means nothing.
A populated green circuit board on a pale bench beside a digital caliper and a strip of screw terminals
Fig. 29Measured values, not verdicts. Ask for the numbers behind a pass.

09The trip, and the way home

Practical terms, and what you bring home.

Fly to SZXOne site per half-dayDebrief the same evening

The three lists a two-day visit produces diverge quickly: what you saw, what you were shown, what you were told.

Two rack-mount units standing in front of an open wooden crate with white foam blocking and a document on the lid
Fig. 30What goes home in the case: samples, a golden sample, marked-up drawings, a written assessment.
01 Fly to SZX If the sites are in Bao'an, the airport is inside the district; Hong Kong adds a border crossing.
02 Get the itinerary in writing Addresses, contact names and mobile numbers, confirmed the day before.
03 Debrief the same evening Write three lists while the day is fresh: seen, shown, and told but not shown.
04 Bring home the evidence Samples and a signed golden sample, the drawings you marked up, and a written assessment with a date on it.
05 Language Bring an engineer who speaks the language of the line, or use ours.
A four-shelf rack unit, two machined quick disconnects, a sealed enclosure, a small panel and a coiled security cable in one row
Fig. 31A golden sample is signed and dated by both sides, and it is what the production run is compared against.
A warehouse aisle between tall racking loaded with palletised cartons, a teal guide line running down the floor
Fig. 32The written assessment is the deliverable. A verbal impression does not survive the flight home.
Two slim rack-mount units standing side by side on a pale floor, photographed square to the camera
Fig. 33A sample unit travels home in the case. The paperwork travels by email.

10Hosted

How a hosted visit works.

Invitation letterItineraryVisa supportEngineering interpretationTours

Invitation letter, itinerary, visa support, engineering interpretation, and the sites that match your product.

A white meeting table with two chairs, a closed laptop, a small circuit board in a tray and a notebook beside a tall window
Fig. 34A working session at the end of each day, not a presentation at the start.
01 Invitation letter Issued with the dates, the host entity and the purpose of the visit, before you book flights.
02 Itinerary Which sites, in which order, with travel time between them.
03 Visa support Document preparation and the paperwork trail, so the application is complete the first time.
04 Interpretation, by engineers Your drawings and engineering changes carried in Chinese by engineers, not by a translation app.
05 Factory tours The network sites that match your product, plus our own PCB and PCBA factory in Bao'an — 45,000 m², 500+ staff.
A foggy aerial view along an industrial waterfront with low warehouse roofs, a road and port cranes in the distance
Fig. 35The district sets the schedule. Sites in one district fit one day.
Two workers in blue overalls loading a palletised carton into a container at a warehouse bay
Fig. 36End the tour where your order leaves, and ask who signs the export declaration.
Sites you would walk
EMS-DisplayEMS EyewearSaturn PCBAWhale PCBAUppcbaKingdta

11Start

Book the visit.

Tell us the product and the decision you want to make. We will build the two days around it.

Recorded. An engineer will reply.

Written technical assessment, from eric@dfshk.cn.

Book a factory visit Our own PCB & PCBA factory eric@dfshk.cn · +86 152 3512 7440