DOMS — Precision CNC Machined Components
Aluminum & steel CNC turning / milling — approx. 30% cost reduction, Section 301 tariffs eliminated
Section 301 Tariff Impact — Before Vietnam Transition
DOMS was purchasing precision CNC machined components from a Chinese supplier subject to 25% Section 301 tariffs under HTS Chapter 84. Vietnam-origin machined parts carry $0 Section 301 tariff — a structural cost advantage that doesn't change with trade negotiations.
About DOMS
DOMS is a U.S.-based industrial manufacturing company sourcing custom precision machined components for its product lines. Led by President Greg L. Wilhite, DOMS needed a reliable offshore manufacturing partner that could match the quality and tolerances of their existing China supply chain — without the tariff burden. After working with Dewin to qualify an audited Vietnam factory, Greg summed it up simply:
"You and the Dewin team are very thoughtful!! It is a joy to do business with you."
— Greg L. Wilhite, President, DOMS
The Challenge
DOMS was sourcing a family of precision-machined aluminum and steel components from a Zhejiang, China supplier. The parts — CNC-turned shafts, milled housings, and drilled flanges — required tight tolerances (±0.01 mm on critical mating surfaces) and consistent surface finishes (Ra 1.6 μm). Quality was adequate, but with 25% Section 301 tariffs (HTS Ch. 84 machinery components), landed cost had become unsustainable.
The added tariff cost represented a significant drag on product margins. DOMS needed a qualified alternative that could hold the same tolerances, accept the same drawings, and deliver without quality regression — with a path to first samples in under 6 weeks.
Why Vietnam?
Vietnam's precision machining sector has grown substantially over the past decade, with many factories running modern Mazak, DMG Mori, and Doosan CNC centers alongside in-house CMM inspection. Our audited network of 60+ CNC factories means we can match virtually any tolerance class or material combination to a qualified supplier.
1. Drawing Review & Factory Matching
Dewin's Vietnam engineering team reviewed DOMS's drawing package. The component family included:
- • CNC-turned precision shafts — 6061-T6 aluminum, tolerances to ±0.01 mm on journals
- • Milled housings — 1045 steel, with tapped holes, reamed bore, and 6-axis feature requirements
- • Drilled and tapped flanges — A2 stainless, surface finish Ra 1.6 μm on sealing faces
- • Surface treatment: hard anodize on aluminum parts; black oxide on steel parts
We shortlisted three Vietnam factories from our audited network with documented experience in multi-material CNC machining and in-house CMM inspection capability — a prerequisite for FAI/PPAP-level documentation that precision industrial customers typically require.
2. On-Site Dolphin Audit
Our on-ground team conducted a 50-point Dolphin audit at the selected facility. Key findings:
- • Machining equipment: 6 Mazak Nexus CNC turning centers + 4 Haas VF-2 vertical machining centers — appropriate for the full component family
- • Inspection: Mitutoyo Crysta-Apex CMM (3-axis, 0.3 μm volumetric accuracy), 2D VMM for secondary checks, full calibration records on file
- • Surface finishing: In-house hard anodize tank (6061/6063 aluminum, 15–25 μm Type III) and black oxide line — no sub-contract delay
- • Quality system: ISO 9001:2015 — certificate verified on-site. FAI reports and PPAP Level 2 documentation available
- • Traceability: Material certs supplied per batch (mill test reports), barcoded work orders, digital inspection records
The factory scored 85/100 on our QCLDM Dolphin audit — a strong result for a precision CNC facility of this size. We presented the full audit report to DOMS before commitment.
3. Sample Production & First Article Inspection
Dewin coordinated the first article production run — 5 pieces of each component — and conducted our own on-site FAI before any samples were shipped to DOMS:
- • All critical dimensions checked on CMM and reported in a full balloon-dimensioned FAI report
- • Surface finish verified with Mitutoyo SJ-210 profilometer on sealing faces
- • Anodize thickness and adhesion tested per MIL-A-8625 Type III acceptance criteria
- • Material certs reviewed and archived; CoC issued by factory
First-article samples arrived at DOMS's facility in 5 weeks from project kick-off. DOMS approved all components on first submission — no dimensional deviations, no rework.
4. Cost Breakdown — Before vs. After
| Cost Element | China Supplier | Vietnam Supplier | Change |
|---|---|---|---|
| Factory Unit Price (FOB) | index: 100 | index: ~82 | −18% |
| Section 301 Tariff (25% on HTS Ch.84) | +25% | $0 | −25 pts |
| Ocean Freight (per shipment) | comparable | comparable | neutral |
| Est. Landed Cost vs China Baseline | 125 (incl. tariff) | ~88 | approx. −30% |
Index-based comparison (China baseline = 100 pre-tariff). Actual savings vary by part geometry, material, and volume. Est. based on typical CNC machined components transitioning from China+25% Section 301 to Vietnam ($0 Section 301).
5. Ongoing Production & Oversight
After first-article approval, Dewin manages ongoing production oversight for DOMS: pre-shipment inspection on every batch (dimensional sampling per AQL 2.5, Level II), photo documentation of each shipment, and monthly factory visits by our Vietnam team. Certificate of Origin documentation for Vietnam-origin goods is provided with every shipment for U.S. Customs clearance — a critical document for maintaining $0 Section 301 status.
Results Summary
"You and the Dewin team are very thoughtful!! It is a joy to do business with you."
— Greg L. Wilhite, President, DOMS