Guide

How do you move CNC machining, die casting and stamping from China to Vietnam with one managed partner?

Short answer

A managed partner is a company that takes the drawing, the purchase order and the inspection plan for a part and places each process at a plant it qualifies and manages, so the buyer deals with one party instead of one supplier per process. Short answer: move the program part number by part number, not all at once. Hand the managed partner one complete RFQ package per part, settle tooling before anything is cut, qualify each part with a first article and a pilot lot, and keep the China source shipping until parts from Vietnam have passed the same inspection plan. Every quote should name the production site and the country of origin for each step.

By Saola Manufacturing engineering team · Published November 7, 2026 · Updated November 7, 2026

This page covers a program that mixes processes: machined parts, die castings, stampings and finishes bought from China today. For a die-cast part alone, see the die casting alternative to China guide; for a machined part moving from a domestic job shop, see transferring machined part production overseas.

On this page

Who is this guide written for?

It is written for a purchasing or supplier-quality engineer at a mid-sized equipment maker who buys a family of custom metal parts from several China suppliers and wants that family made in Vietnam without adding several new suppliers to manage.

A typical program looks like this: a turned brass or steel fitting from one China machine shop, an aluminum housing from a China die caster that also drills and taps it, a stamped steel bracket from a third supplier, and plating or powder coat arranged by whichever supplier ships last. Each supplier has its own quote, its own purchase order and its own inspection report, and the buyer is the only party that sees all of them.

Moving that program to Vietnam raises a choice that a single-process move does not. You can find a direct supplier in Vietnam for each process, hand the whole family to a sourcing agent, or give it to one managed partner that runs part of the work at its own lead plant and places the rest at partner plants it manages. This guide compares those routes honestly, including where one managed partner is the wrong answer.

When does one managed partner beat several direct suppliers?

When the parts in the family pass through more than one process, and the handoffs between processes are where your rejects come from today. It loses when one process dominates the family and you have the staff to manage that supplier directly.

One managed partner tends to win when:

Parts cross process boundaries. A casting that has to be machined and then coated, or a stamping that needs a tapped hole and a plated finish, moves between plants. Someone has to define the condition each part is handed over in, and inspect it at the handoff. With direct suppliers, that someone is you.
You want one answer for a reject. When a bore is out of position on a coated casting, separate suppliers can each point at the other step. A partner holding the whole purchase order has to find the cause and fix it.
Your team cannot visit several plants. Qualifying, auditing and following up a machine shop, a die caster, a stamper and a finisher in a new country is real work. A managed partner does that work, and your audit effort goes into the partner and the production sites its quotes name.
The family is many low-drama part numbers. Brackets, bushings, covers and fittings at steady annual volumes are easier to move as one package than as a dozen separate supplier hunts.

Several direct suppliers tend to win when:

One process is most of the spend. If the family is mostly die castings, a direct relationship with a die caster gives you the tool shop's engineers on the phone and no middle margin on the largest share of cost. The one-supplier die casting and machining guide sets out that trade-off for castings.
You already have people in the region. A buyer with its own supplier-quality engineers in Vietnam can manage handoffs directly, and the partner's coordination is then cost without much benefit.
You need the named plant on your approved supplier list. Some quality systems require the actual producing plant, not the partner, to be the approved supplier. Check that before you choose a route.

How do one managed partner, direct suppliers and a sourcing agent compare?

They differ in who holds the purchase order, who actually runs the processes and who answers for a reject. The table describes the three buying models in general, not any named company.

The sourcing-agent column means an agent that runs no plant of its own and passes orders to third-party plants. Many agents do good work; the point is where accountability sits, not the quality of any one firm.

One managed partner vs separate direct suppliers vs a sourcing agent with no plant of its own · general buying models, not named companies; origin row per 19 CFR 134.1 (eCFR, 2026)
Question	One managed partner	Separate direct suppliers	Sourcing agent (no plant of its own)
Who holds the drawing and the purchase order	The partner, for every process on the part	Each supplier, for its own step	The agent, or the plant directly, depending on the contract
Who runs the processes	Some at the partner's lead plant, the rest at partner plants it manages	Each supplier runs its own process	Third-party plants; the agent runs none
Handoffs between processes	Defined and inspected by the partner	Defined by the buyer; parts may move between suppliers	Coordinated by the agent's staff
Who answers for a dimensional reject	The partner, whichever step caused it	The buyer has to trace which step caused it	The agent, backed only by its contracts with the plants
Direct contact with the die caster or stamper	Through the partner	Yes	Usually through the agent
Margin between you and the plant	On the steps it places with partner plants	None	On every step, as a fee or markup
Engineering on the floor	At its own lead plant for its own process; at partner plants for the rest	Each supplier's own	Depends on the agent's engineers
Production site disclosed	Should be named on every quote, with country of origin	Known, since you buy from the plant	Varies; ask for it in writing
Country of origin	Where the last substantial transformation happens	Same rule	Same rule
Suppliers you qualify and audit	The partner, plus the plants it names	Every supplier	The agent, and the plants if it discloses them

What runs at Saola's lead CNC plant, and what goes to managed partner plants?

CNC turning and CNC milling run at Saola's lead CNC plant in Vietnam. Die casting, stamping, surface finishing and the other processes go to partner plants Saola manages, and the quote names each production site and the country of origin.

The lead CNC plant has 12 machining centers and 9 CNC lathes, as listed on the CNC milling and CNC turning pages. That is where machined parts are made, and where castings and stampings come for their machined features when a part needs them.

Saola does not own a foundry or a stamping line. Die casting, stamping and surface finishing are done by partner plants that Saola manages. Partner plants are not named on this site, but every quote names where each step of your part is made and the resulting country of origin. A part made outside Vietnam is not Vietnamese origin, and it is never presented as such.

In practice, for a mixed program that means:

Turned and milled parts are machined at the lead CNC plant.
Die castings are cast at a managed partner plant, then machined at the lead CNC plant where the drawing calls for machined faces, bores or threads.
Stampings are made at a managed partner plant, with any secondary machining routed as the quote states.
Finishes such as anodizing, zinc plating and powder coat are applied at managed finishing plants.
Inspection and the paperwork (first-article report, lot records, origin file) come back to you from Saola under one purchase order per part number, as listed on the quality page.

Certification status, stated plainly: ISO 9001 is not held yet; certification is in progress.

Should you transfer the China tooling or build new tools?

Decide per tool, after you know who owns it, what condition it is in and whether the receiving plant can run it. Transfer saves tool cost but brings the old tool's wear and the old supplier's cooperation into your schedule.

Die-casting dies and progressive stamping dies are the expensive items in a mixed program, and they are often the reason a move stalls. Start by getting ownership in writing: a tooling invoice you paid is not always proof of title, and some China contracts let the supplier keep the tool until a final balance is settled. The tooling ownership guide lists the terms to check.

Then judge each tool on its own:

Transfer when the tool is in good condition with plenty of life left, the drawing has not changed, and the outgoing supplier will release it with its maintenance records. The receiving plant still has to confirm that the tool fits its machines before anyone ships it.
Build new when the tool is near the end of its life, needs a design change, is held back by the old supplier, or was built for a machine the receiving plant does not run. New tooling also lets you fix features that have caused trouble in the past.
Machining fixtures are usually cheaper to rebuild than to ship, and a new fixture designed around the lead plant's machines is often the cleaner choice.

One customs point applies either way. If you supply a die or mold to the new source free or below cost, it is an assist, and its value belongs in the customs value of the imported parts (19 CFR 152.102). Tell your customs broker before the first entry.

What goes in the RFQ package for a multi-process part?

Everything each process needs, plus what defines the handoff between processes. A package that only works for machining will come back with questions on the casting, the stamping or the finish.

Current drawing and 3D model for every part number, at the revision you actually buy to, with a STEP file where you have one. The RFQ package guide covers the general list.
As-cast and as-stamped condition. If the drawing only shows the finished part, mark which faces are machined after casting, and what machining stock the casting carries.
Material as received, not only as drawn. If the drawing says one alloy and your China supplier has been shipping an equivalent, say which one you want matched.
Finish callouts with the standard, type and class, color references, masking and whether dimensions apply before or after the finish.
Annual volume and release pattern per part number, and whether volumes are firm or forecast.
Tooling status for each tool: owned or not, transfer or new, and its condition if you know it.
Inspection expectations: critical features, the first-article format you want and any PPAP-style submission. The PPAP guide explains which level is worth asking for.
Retained reference parts and recent inspection reports from the China supplier, so differences can be traced to the old source or the new one.
Your HTS code for each part, so the quote can note the origin of each step against it.

Ask for the quote to come back with the production site and country of origin for each step, the tooling plan, and the inspection plan. If a quote cannot tell you where your part will be cast or stamped, you cannot judge it.

How do you qualify the Vietnam source without stopping China supply?

Qualify one part number at a time with a first article and a pilot lot, and keep the China source shipping until the Vietnam parts have passed the same inspection plan. Release volume only in writing, on a date everyone knows.

Pick the first parts. Start with part numbers that represent each process but are not your most critical. A machined part, one casting and one stamping make a better first wave than ten machined parts.
First article. Every toleranced dimension is measured on the first piece off new or transferred tooling, not only the features marked critical, and compared with your retained parts. The first article guide lists what the report should contain.
Requalify the finish. A new finishing line is a new process, even to the same callout. Approve color and appearance on physical samples.
Pilot lot. Run a small production lot through the full routing and inspect it at your dock as you would a normal lot. A first article proves the tool; a pilot lot proves the process holds over a run.
Build the origin file. Keep the routing showing where each step happens, with material sources. Under 19 CFR 134.1, origin follows the country where the article is manufactured and later work must be a substantial transformation to move it, so a China casting that is only machined or coated in Vietnam may not become Vietnamese. The casting and machining origin guide covers that question.
Consider a binding ruling for your highest-exposure parts. CBP generally rules only on prospective transactions (19 CFR 177.1), so request it before the first shipment; see how to request a binding ruling.
Overlap the sources. Size your last orders with the China supplier to cover qualification plus a failed first article. For tools that are being transferred, that bridge stock has to be built before the tool leaves. The dual sourcing guide covers whether to keep both sources running for good.

Duty is part of the business case, not this checklist. The tariffs and origin page and the transshipment guide cover the current rules; compare landed cost on your own HTS code with your broker.

Who does this fit, and who should look elsewhere?

It fits recurring production of custom metal parts at annual volumes from a few thousand into the hundreds of thousands per part number. It does not fit prototypes, one-off builds or programs that need a supplier with a registered quality system today.

Tooling and qualification are paid back over production volume, so the case is strongest for steady, repeat part numbers: fittings, housings, brackets, bushings and covers for industrial equipment. A program that is mostly prototypes is better served by a local shop close to your engineers.

Look elsewhere, or keep a direct supplier, if:

your quality system requires suppliers registered to ISO 9001 now (Saola's certification is in progress, not held yet);
you need the producing plant named as the approved supplier on your list, and cannot accept the partner as the supplier of record;
the family is almost all one process and you have the people to run that supplier directly;
you need aerospace or medical-device regulatory scope, which Saola does not offer.

To vet any Vietnam supplier, partner or plant, the supplier vetting guide lists what to ask for and what to check on a visit.

Frequently asked

Does Saola do its own die casting or stamping?

No. CNC turning and milling run at Saola's lead CNC plant. Die casting, stamping and finishing are done at partner plants Saola manages, and the quote names each production site and the country of origin.

Are the partner plants named?

Not on this site. Each quote states where every step of your part is made and the country of origin, and you can set out your audit requirements in the RFQ.

Can we move only part of the program?

Yes. Many buyers start with the machined parts and one or two castings or stampings, and keep the rest with their current suppliers until the first wave is qualified.

Should we stop buying from China once the first article passes?

Not yet. A first article proves the tool, not the process over a run. Keep the China source shipping until a pilot lot has passed the same inspection plan, then release volume in writing.

Is a managed partner more expensive than buying direct?

It can be on the steps it places with partner plants, because the coordination and inspection are part of the price. Whether that costs more overall depends on what your team spends today managing handoffs, rejects and several suppliers.

Sources

19 CFR 134.1, Definitions (country of origin), Electronic Code of Federal Regulations, accessed November 2026
19 CFR 152.102, Definitions (assist), Code of Federal Regulations, via Cornell LII, accessed November 2026
19 CFR 177.1, General ruling practice and definitions, Code of Federal Regulations, via Cornell LII, accessed November 2026