Why tooling work is moving to Vietnam — and what the supply base still cannot do

Vietnam did not set out to build a tool and die industry. It got one as a side effect of two decades of electronics assembly and injection moulding: when you run thousands of moulds, you eventually need people who can repair and then build them locally.

That base is now real enough to be worth sourcing from. It is also uneven, and the gap between the good shops and the rest is wider than in more mature markets.

What is genuinely there

Mould and die work at scale. Binh Duong, Dong Nai, Hai Phong and the Hanoi industrial belt have a substantial population of shops doing injection mould bases, cavity and core plates, stamping dies and progressive tooling. Much of it grew up supplying Japanese and Korean manufacturers, which brought their drawing standards and their quality expectations with them.

Material availability. The grades that matter are stocked domestically — P20/1.2311, 1.2738, H13/SKD61, D2/SKD11, S50C, 4140. Service centres in Ho Chi Minh City and Hanoi carry common sections. This matters more than it sounds: a grade that is in stock ships this week, a grade that has to be imported takes four to six. Naming acceptable grade equivalents is the difference.

Wire EDM and sinker EDM capacity. Widely available and competitively priced, because die repair demanded it.

Heat treatment. Commercial vacuum heat treatment exists, concentrated around the major industrial zones. Quality varies considerably and this is worth checking specifically.

Cost position. Machining labour runs meaningfully below coastal China and well below Japan, Korea or the EU. The gap has narrowed but it has not closed.

What is thinner than the marketing suggests

True hard milling capability. Plenty of shops own machining centres that could hard mill. Fewer have the shrink-fit holders, the CBN grades, the dry-cutting practice and the temperature control to do it reliably at 58-62 HRC. This is the capability that has to be verified rather than assumed — see the eight vetting questions.

Precision grinding. Jig grinding and high-precision surface grinding are genuinely scarce. A part needing 0.002 mm flatness or a jig-ground bore position may have to go to one of a small number of shops, with the lead time that implies.

Metrology at the tight end. CMMs are common. CMMs in temperature-controlled rooms, with calibrated scales and a dedicated operator, are less common. For ±0.005 mm work this is a real constraint and the first thing to ask about.

Surface integrity awareness. Nital etch for thermal damage, residual stress control, controlled tool change intervals on finishing passes — this is mature practice in aerospace supply chains and much less established here. If your part is fatigue critical, specify it explicitly rather than assuming it. See white layer.

Large sections. Very large blocks — 500 mm and up — are less commonly stocked and fewer machines have the envelope and the rigidity for them at hardness.

What has actually changed recently

Three things, all supply-side rather than demand-side:

Supply chain diversification. Buyers who previously single-sourced tooling from China have been adding a second source. Vietnam is the nearest alternative with a comparable industrial culture and similar logistics.

The electronics build-out. Large-scale electronics investment brought precision tooling demand with it, and that demand pulled local capability upward. Shops that were doing rough die repair five years ago are doing cavity work now.

Engineer availability. Vietnamese technical universities produce a steady supply of mechanical engineers, and enough of them have worked inside Japanese and Korean manufacturing operations to have absorbed those process standards.

How to source it without getting burned

Verify hard machining capability specifically. Do not accept “we do CNC machining” as an answer to “can you finish at 60 HRC”. They are different claims.

Be explicit about the things that are less standard here. Inspection temperature, surface integrity requirements, heat treat certification, datum re-establishment after heat treat. In a mature aerospace supply chain these are assumed. Here, write them down.

Ask where heat treatment goes. Most shops outsource it. Which heat treater, vacuum or atmosphere, and do they get a certificate back? A shop that manages its heat treater is different from a shop that just ships parts across town.

Allow the grade substitution. The single biggest lever on lead time.

Start with a trial part. Not a full tool. One representative component with a real tolerance on it. It costs a few hundred dollars and tells you more than any audit.

Be realistic about communication. Written English is generally workable for technical detail; a complex design discussion on a call is harder. Send drawings, send models, put requirements in writing, and expect written answers.

Where it fits

For production tooling at moderate to high precision — mould plates, cavity and core blocks, stamping dies, wear components, die sets — Vietnam is competitive on cost and increasingly competitive on capability.

For ultra-precision work, jig-ground components, or anything requiring aerospace-grade process documentation, the supply base is thin and you will pay for the few shops that can do it, if you find them.

Knowing which of those your part is saves a lot of time. Send the drawing with the tolerance and the application, and the answer usually comes back in the same day.