One Machine, Five Operators, Zero Overtime

A contract packaging facility in Shenzhen ran two single-head forming machines producing rigid phone boxes — 180×90×50mm, 40,000 units per day. Each machine needed one operator to load blanks, one to unload and inspect, plus a floater covering breaks. Five people total per shift, two shifts. Ten operators. Monthly labor cost: roughly 65,000 RMB all-in.

They replaced both single-head machines with one Zray ZC-D900 double-head high-speed forming system. Same production floor footprint — 4.2m × 2.8m. Staffing dropped to one operator feeding both magazine feeders and one inspector at the shared discharge conveyor. Four people total across two shifts. Labor cost: 26,000 RMB. Annual savings: 468,000 RMB, against a machine cost of roughly 380,000 RMB. Payback in under 10 months, before factoring in the 18% throughput increase from eliminating inter-machine transfer time.

What “Double-Head” Actually Means in Practice

A double-head forming machine runs two independent forming stations fed by a single blank-feeding system. Both stations share the main frame, vacuum system, glue application unit, and PLC controller — but each has its own forming plunger, folding rails, pressing station, and discharge path.

The two heads operate on alternating cycles. While Head A is pressing a formed carton, Head B is picking the next blank. This staggered timing eliminates the idle window that a single-head machine spends on the return stroke. Result: effective throughput of 50–65 cartons per minute on standard sizes, versus 30–38 on a single-head machine. It’s not quite 2× speed because the shared feeder and discharge systems create a bottleneck at very high speeds, but it’s a solid 60–70% throughput gain with zero additional labor.

The Labor Math, Line by Line

Traditional single-head setup for 40,000 units/day:

| Role | People/Shift | Shifts | Total |
|——|————-|——–|——-|
| Magazine loader | 1 | 2 | 2 |
| Machine operator | 1 | 2 | 2 |
| Discharge/inspection | 1 | 2 | 2 |
| Floater/QC | 1 | 2 | 2 |
| Supervisor (shared) | 0.5 | 2 | 1 |
| Total | | | 9 |

Double-head setup for same volume:

| Role | People/Shift | Shifts | Total |
|——|————-|——–|——-|
| Magazine loader (feeds both heads) | 1 | 2 | 2 |
| Discharge inspection | 1 | 2 | 2 |
| Supervisor (shared) | 0.25 | 2 | 0.5 |
| Total | | | 4.5 |

The machine operator role disappears because the double-head system’s PLC handles forming synchronization, glue registration, and jam detection automatically. The ZC-D900’s control panel lets one person monitor both heads from a single touchscreen.

When Double-Head Doesn’t Make Sense

Double-head machines cost roughly 65–80% more than equivalent single-head machines. If your daily volume is under 15,000 units, the labor savings won’t justify the capital cost. Run the breakeven:

• Single-head machine: 220,000 RMB, needs 3 operators/shift, 40 cartons/min
• Double-head machine: 380,000 RMB, needs 1.5 operators/shift, 65 cartons/min
• Labor cost: 6,500 RMB/month per operator

At 15,000 units/day, a single-head machine runs 6.25 hours per shift. A double-head runs 3.85 hours. The labor saving is 1.5 operators × 6,500 RMB × 2 shifts = 19,500 RMB/month, or 234,000 RMB/year. The 160,000 RMB price premium pays back in about 8 months. Below 15,000 units/day, the payback stretches past 18 months, and you’re better off optimizing your single-head operation.

The Hidden Saving: Changeover Labor

Single-head machines running multiple SKUs need the operator to stop production, adjust forming rails and glue parameters, test-run 5–10 cartons, and restart. A 6-SKU day means 5 changeovers, roughly 3 hours of operator time.

The ZC-D900 stores 20 parameter sets in the PLC. The operator selects a SKU number on the touchscreen, and servo motors reposition the forming rails, glue rollers, and pressing plate to the stored positions. Changeover drops to 6–8 minutes, mostly spent verifying the first-off carton. Over a month of multi-SKU production, that’s 40–50 operator-hours saved — roughly half a person’s full-time equivalent.

If your plant runs a single carton SKU 24/7, buy a single-head machine and invest the savings elsewhere. If you run multiple SKUs above 15,000 units/day, the double-head system’s labor math is hard to argue against.