An empty meeting-room table in Shenzhen with a laptop, a sample board in a tray and a notebook under a tall window

Contact · Shenzhen, UTC+8

Send us your spec

Send the file. You get a written technical assessment back, and the reply comes from an engineer, not a chatbot.

Written assessment FOB default Files read by an engineer

Email — fastest for files

eric@dfshk.cn

Phone & WhatsApp

+86 152 3512 7440

Where we are

Shenzhen, Guangdong, China

Working hours

Mon–Sat · UTC+8

01Start the file

One line is enough to open it.

Written technical assessmentReply from an engineer

A dimensioned technical drawing flat on a pale bench with a thin pen and folding dividers — Fig. A Gerber, BOM and the drawing are what the assessment is written from.

Recorded. An engineer will reply.

From eric@dfshk.cn. Reply to that message with the drawing attached.

02What to send us

Seven items turn a price into an assessment.

Gerber + BOM is enough to start

Technical drawings with digital calipers, a drafting triangle and machined sample parts on a pale bench — Board work Gerber or ODB++ with the fabrication drawing.

A production panel of identical green circuit boards held in a white inspection fixture — The BOM Manufacturer part numbers, and any part that is single-sourced.

A finished rack server power supply module with a perforated intake face and a gold edge connector — Finished product Enclosure, connectors, cable entry and the thermal path.

01 The file Gerber or ODB++, plus the fabrication drawing that decides everything downstream.

02 The BOM With manufacturer part numbers, and any part you know is single-sourced.

03 Stackup and finish Impedance targets, materials and surface finish you need.

04 Target class IPC-A-610 Class 2 or Class 3 — IPC puts that decision on you.

05 Quantities First order and annual, with the re-order pattern if you know it.

06 Target price The number you need to hit, and whether it is landed or FOB.

07 Destination market Country of import, so the compliance and tariff list is right the first time.

Adding the stackup and target class is what makes the assessment address the Class 3 cost step: 20–40% over Class 2 (industry guidance).

03What happens after you press send

Five steps, with the clock on each one.

Report in 24–48 h4 h expedited

A clipboard holding a blank ruled form with a pen and a teal sticky tab, photographed from above — Fig. B Open questions come back in writing.

A dimensioned engineering drawing sheet with a pencil and a pair of dividers laid over it — Fig. C The quotation names the site and the standards.

An open shipping container at a loading dock with unlabelled cartons stacked on a pallet inside — Fig. D The inspection report releases the balance.

Step 1 · one working day Acknowledgement From the engineer who will own the file — the same target one network site publishes.

Step 2 Written technical assessment Stackup and DFM review, class and its cost, BOM notes, compliance gaps, test plan, open questions.

Step 3 Quotation on FOB terms Naming the site that would build it and the standards it would be inspected against.

Step 4 · 24–48 h report Optional third-party testing The sample goes to SGS, TÜV, Intertek, Bureau Veritas or UL, reporting to you.

Step 5 · booked a week ahead Pre-shipment inspection AQL defaults critical 0, major 2.5, minor 4.0; 48 hours' notice to the factory.

04Who replies, and in what language

An engineer signs the answer.

Service line 4 of 6Service line 2 of 6

An engineer's hands at a bench under an inspection lamp, working on a board with tweezers beside an open laptop — Fig. E The report is signed by whoever read the file.

Two pairs of hands over a technical drawing, one pointing at a dimension with a pen — Fig. F The Chinese-language engineering thread happens on our side.

Technical The engineer who read it Name and date on the assessment; commercial terms ride with the same contact.

Factory side In Chinese, in writing Drawings, stackups, BOM queries and engineering change notices.

Not yet known Written as such You get "not verified yet" with the date it will be answered by.

The engineering & solutions team

05Book a factory visit instead

Two days in Shenzhen, hosted end to end.

Invitation letterVisa supportItinerary

A single visitor in a white coat walking the aisle of a bright assembly hall between rows of machines — Fig. G Partner sites matched to your product, added to the same week.

An SMT line seen down its length, pick-and-place machine and reflow oven with boards on the conveyor — Fig. H Our own PCB & PCBA factory: 45,000 m² in Bao'an, 500+ staff.

We arrange The whole week Invitation letter for the visa, itinerary, hosted tour, interpretation, meeting schedule.

We do not Stage a showroom No certificate walls, no factory signage, no certificate holder name, no showroom instead of a line.

One trip covers Backstop and source 24 partner sites across 5 capability groups can join the same itinerary.

China visit & factory tours Questions buyers ask us

06Start

A written technical assessment, not a price list.

Default term is FOB; FCA where the goods are stuffed inland. We do not quote EXW.

Recorded. An engineer will reply.

Written technical assessment, from eric@dfshk.cn.

The technical assessment service eric@dfshk.cn · +86 152 3512 7440