Reverse engineering

Send the part. We work backwards from it.

If the CAD does not exist — because the part came from a supplier who disappeared, or from a machine nobody supports anymore — a physical sample is a perfectly good starting point. It just has to survive the trip and clear customs without being held.

What actually happens

Four steps, in order. Step one is the only one that needs anything from you beyond an email.

You email first, then ship

Tell us what the part does, what it mates with, and the material if you know it. We reply with the address confirmation and any customs wording your carrier will ask for. Shipping without that email is how parcels sit in a warehouse for three weeks.

We photograph and measure what arrived

Photographs before anything is touched, dimensions recorded, condition noted. If the part arrives damaged we tell you and photograph that too, before we decide whether it is still usable.

Scan, then model

The part is scanned or measured feature by feature, and rebuilt as a CAD model. You get the model or a drawing to check before anything is machined — this is the step where a wrong assumption about a thread or a radius gets caught for free.

Quote, first article, batch

The quote follows the model, not the other way round. Then one first article for your approval, then the batch. If the part turns out to be unmakable in the material you wanted, you hear it at this step instead of after a run.

Ship-to address

Print this block and put it inside the parcel as well as on the outside. Print styles are set up for this page — use your browser's print command and you get the card without the navigation.

Sample receiving

YOUR NAME
ProtoBridge

FULL STREET ADDRESS
DISTRICT, CITY
PROVINCE POSTAL CODE
China

Tel: PHONE — must accept international parcels
Email: engineering@YOUR DOMAIN

Phone number matters. Chinese customs and couriers call the receiver. A number that nobody answers is the most common reason a sample is returned to sender.

Sample parcel with customs form beside a worn part and caliper

Customs wording that avoids a held parcel

Copy this onto the customs declaration. It is ordinary practice for samples, and it is what the carrier expects to see.

Description: "Customer sample for inspection — no commercial value."

Declared value: a nominal value, stated honestly. Do not declare zero — a zero-value declaration gets questioned, and an under-declared parcel gets held or fined.

Include inside the parcel: the drawing if you have one, or a one-page note saying what the part does, what it mates with, the material if known, and the quantity you expect to order. That note is often more useful than the drawing.

Situation	What to write
Broken or worn part	"Worn sample part for reverse engineering — no commercial value." Add a note on which surfaces are worn versus original.
Competitor's part you want matched	Same wording. No brand names in the description; the brand goes in your email, not on the customs form.
Several small parts	"Assorted sample parts for inspection — no commercial value." List each one on the packing list with a rough description.
Hazardous material	Tell us before shipping. Magnets, powders and some ceramics have carrier restrictions by air.

What happens to your part

People get attached to the only sample they have. Fair enough — here are the rules.

Returned on request: Yes, at your cost, and we will tell you the shipping cost before sending it back.
Damaged or destroyed: Some parts have to be sectioned to measure an internal feature. If that is likely, we ask first — and we photograph the part before and after, so you can see exactly what was done.
Kept for repeat orders: We keep the sample and the model together so a second order does not restart from zero. Ask us to return it and we will.
Confidentiality: A physical sample is treated the same as a drawing. See NDA & IP.
Cost: You pay the outbound shipping to us. The scan, the model and the DFM review are free — they are how we earn the quote.

Email before you ship.

One line is enough: what the part does, roughly how many you need, and when you need them. We will reply with the address confirmation and anything your carrier will ask for.

Email us before shipping

Or put the whole request in the quote form — eight fields, no account.