SBAL-V auto duct line replaces 10-operator manual workshop in Ho Chi Minh City

The buyer and the situation before the line

The buyer is a mid-size HVAC duct fabrication workshop in Ho Chi Minh City supplying rectangular ductwork to commercial mechanical contractors across southern Vietnam — office towers, hotels, shopping centres and the early waves of data-centre fit-out work that arrived in the Vietnamese market between 2021 and 2023. The business had grown from a single-operator hand-forming shop in the early 2010s into a ten-operator workshop running traditional sheet shears, bar folders, lockformers and drive cleat machines in a sequence of independent stations. Output was roughly 350–400 m² of finished duct per day when everything went well, which was most days but not every day. The workshop owner had been thinking about automation for three years — what finally pushed the decision was a mechanical contractor on a large hotel project who quoted a weekly duct delivery volume that the hand-forming workshop could not meet without either hiring five more operators or turning the contract down.

Why the workshop chose the SBAL-V over a mid-range line

The buyer evaluated three options: a local semi-automatic line from a Vietnamese equipment supplier, an SBAL-III from SBKJ, and an SBAL-V from SBKJ. The local line was the cheapest at roughly 60% of the SBAL-V price but had no integrated Pittsburgh lockformer and a weaker CNC control, which meant the workshop would still need two hand-forming operators downstream for seam assembly. The SBAL-III was priced in the middle and would have met the current workload comfortably at around 1,200 m²/day, but the buyer was concerned about the headroom in front of a rising market. The SBAL-V was the most expensive but had enough rated throughput (2,500 m²/day) that the workshop could absorb the hotel contract, take on a second mechanical contractor the following year, and still not be capacity-constrained. The decision to step up one model was the single most important decision the buyer made — by the end of year one the workshop was running at roughly half of the SBAL-V's rated throughput and had already stopped taking calls from contractors they could not previously service.

The machine configuration

The machine selected was an SBAL-V-1250U with the following specification:

• Coil width: up to 1,250 mm (the U version)
• Material: galvanised steel GI 0.5–1.0 mm
• Seam: integrated Pittsburgh lock forming, with S-cleat and drive cleat options
• Target output: 1,200 m²/day on a single shift at the buyer's site; 2,500 m²/day rated on two shifts
• Control: Siemens PLC with 10-inch HMI, Vietnamese and English language packs
• Power: 380V 3-phase 50Hz (matching Vietnamese mains supply)
• Options: TDF flange forming in-line, beading and notching, integrated decoiler with electric braking

Two decisions are worth calling out. First, the buyer chose the 1,250 mm coil width rather than the smaller 1,000 mm version because roughly 15% of the buyer's contracts specified duct that exceeded what a 1,000 mm line could produce in a single seam — giving up those contracts was not commercially acceptable, so the extra coil-width capability paid for itself within six months. Second, the buyer opted for the integrated TDF flange module rather than a standalone TDF machine downstream; this was marginal on a line throughput basis but eliminated one handling step and one operator from the downstream assembly station.

Installation timeline — 58 days from order confirmation

The timeline below is drawn from the SBKJ project file and cross-checked against the buyer's own commissioning report.

• Day 0 — order confirmation. Deposit received, SBKJ Jiangyin factory scheduled the build slot.
• Day 0–28 — factory build. Structural steel, sub-assembly, electrical cabinet, and integration completed in the Jiangyin factory on the standard SBAL-V build schedule.
• Day 29–35 — in-house test bay. Full machine run-up and no-load test using SBKJ stock coil.
• Day 36 — factory acceptance test (FAT). The buyer sent their workshop manager to the Jiangyin factory. The machine ran the full SBAL-V cycle on the buyer's nominated coil gauge (0.8 mm GI) and the FAT report was signed. Final payment released.
• Day 37–45 — packing and dispatch. Machine crated, loaded into a 40-foot high-cube container, and trucked to Shanghai port.
• Day 46–52 — sea freight. Shanghai to Ho Chi Minh City Cat Lai port (standard 6-day transit on this route).
• Day 53–58 — on-site commissioning and training. SBKJ commissioning engineer flew to Ho Chi Minh City. The machine was lifted into the workshop, levelled, connected to the 380V supply, fired up, calibrated against the buyer's first contract coil, and the three nominated operators were trained on the HMI, the daily maintenance routine, and the changeover procedure. The machine produced its first saleable duct on day 57 and ran at full production on day 58.

First-year results — before and after

The buyer ran the SBAL-V for twelve months before agreeing to share the results for this case study. The numbers below come from the buyer's own production log and cost accounting, not from SBKJ measurements.

• Daily output: 350–400 m² (before) → 1,100–1,350 m² (after). Roughly a 3x lift on a single shift.
• Operators on the duct production station: 10 (before) → 3 (after). The seven operators freed up were reallocated to the install-team side of the business — the buyer's install crews were the bottleneck once the production line stopped being the bottleneck.
• Rework rate: ~5.5% (before) → ~0.8% (after). The hand-forming station was producing about 20 m² of rework per day; the SBAL-V is producing about 10 m² of rework per day at three times the output.
• Scrap rate: ~5.8% (before) → ~1.2% (after). Scrap is down because the CNC dimension setting eliminates the measurement errors the hand-forming station was making on odd-size runs.
• Tolerance: ±3–5 mm (before) → ±0.5–1.0 mm (after). Mechanical contractors started specifying tighter tolerances on their contracts once the buyer could demonstrate the SBAL-V capability.
• Changeover time between jobs: 15–25 min (before) → 3–8 min (after). The CNC program library on the HMI eliminated manual re-setting of the forming stations.

Challenges encountered

The project was not entirely frictionless and it would be dishonest to pretend otherwise. Three specific challenges came up.

First, the workshop electrical supply was weaker than expected. The nominal 380V supply sagged to roughly 360V during the peak daytime load — the SBAL-V would still run but the main motor was drawing slightly more current than ideal. The fix was an isolating transformer installed by a local electrician in the first week of operation. SBKJ should have asked for a voltage stability measurement as part of the pre-install questionnaire and has added that step to the pre-install checklist for Southeast Asia deliveries.

Second, the Vietnamese operator training took longer than expected. The three operators the buyer nominated were experienced hand-formers but had never worked with a CNC control before. SBKJ's standard five-day training programme was enough for the basics but the operators needed a further three weeks of hand-holding over video call from the Jiangyin engineer to become fully self-sufficient on changeover and fault diagnosis. SBKJ has since added a structured 30-day post-commissioning video support programme to its Southeast Asia deliveries.

Third, the buyer's first coil batch from a new local supplier had inconsistent surface oil, which caused the Pittsburgh lockformer to slip on roughly 2% of the early panels. The fix was a temporary change of coil supplier while the original supplier's oil application was corrected. This had nothing to do with the SBKJ machine but it was a surprise to the buyer and is worth mentioning because every new line starts with a coil supply quality baseline that the buyer cannot completely control.

What this case means for similar buyers

A workshop running 350–400 m²/day with ten operators is at almost exactly the point where an auto duct line stops being a luxury and starts paying for itself within the first year. The buyer in this case study had already crossed that threshold and had been operating past it for roughly two years before the hotel contract forced the decision — had they automated twelve months earlier they would have captured an additional year of margin expansion. If you recognise your own workshop in this description, the honest conversation with SBKJ is not about whether to automate but about which model is the right fit for your throughput profile and your market headroom. The auto duct line choosing guide walks through the specific questions an SBKJ engineer will ask you.

One more observation: the buyer in this case chose the SBAL-V rather than the SBAL-III specifically for the market headroom. That decision cost them about 25% more capital upfront and returned within roughly eight months of full production. In a growing market the cost of being capacity-constrained is almost always higher than the cost of buying one size up — if you are debating SBAL-V vs SBAL-III, read the SBAL-V vs SBAL-III comparison and think carefully about whether your market is growing or steady.

Related resources

• SBAL-V product page — full specification for the machine described in this case study
• How to choose an auto duct production line — the decision framework SBKJ engineers use with buyers
• SBAL-V vs SBAL-III line comparison — capacity, cost and headroom
• Southeast Asia regional page — LC payment terms, port logistics and voltage
• Quality control page — ISO 9001:2015 procedure and FAT procedure

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