The Factory Acceptance Test You Cannot Attend

A food packaging company in Santiago, Chile ordered a ZF-420D in Q4 2024. Their engineering team had planned to send two technicians to the Zray factory in Dongguan for the FAT. Two weeks before the visit, visa delays made the trip impossible. The machine was due to ship in 21 days. Missing the FAT meant delaying shipment by six weeks or verifying the machine remotely.

We ran that remote FAT over three days using live video, real-time PLC data via VPN, and third-party dimensional inspection. The machine shipped on schedule. Six months later, the Santiago plant reports 97.2% OEE — higher than the 95% contractual target.

What a Proper FAT Covers

A Factory Acceptance Test is not a demonstration — it is contractual verification that the machine meets purchase order specifications before shipment. Skipping FAT means discovering non-conformances after the machine has crossed an ocean and been installed.

A standard Zray FAT covers five verification categories:

1. Dimensional and Build Verification. Confirm the machine matches the approved layout drawing and the contract technical appendix. Verify every specified component: servo motors (Siemens 1FL6 series), PLC (Siemens S7-1200), HMI (Siemens KTP700 Basic), glue system (Nordson ProBlue), pneumatics (SMC cylinder models), and all safety devices. Walk around with the component list in hand. Do not assume — check. We have caught incorrect pneumatic cylinder strokes during remote FATs where wrong models were installed during assembly.

2. Dry Cycle Test. Run at 100% rated speed without cardboard or glue for 30 uninterrupted minutes. Monitor servo current on the PLC data mirror — all axes should stay below 80% of rated current with no load. Listen through the live audio feed for any irregular mechanical impact or scraping. Verify that every pneumatic actuator completes its full stroke within the allotted cycle window. Any servo fault or pneumatic timeout during the dry cycle is a fail.

3. Production Test. Run 500+ cartons with the buyer’s actual cardboard and glue, at 80% of rated speed for the buyer’s carton design. Reject rate must stay below the contractual limit — typically 2% for standard straight-wall cartons, 3% for designs with tight corner radii or multi-panel construction. The camera stays fixed on the ejection conveyor; the buyer counts rejects alongside the Zray operator.

4. Dimensional Accuracy. Pull 50 cartons at random intervals from the production run. Measure length, width, and height at panel center with a calibrated digital caliper (resolution 0.01 mm). Tolerance: ±0.5 mm from specification for standard cartons. Crease fold angle: 90° ±1° measured with a digital angle gauge. Glue seam width and position measured and recorded. All 50 data points go into the shared spreadsheet in real time.

5. Safety Verification. Actuate every E-stop while the machine runs at production speed — each must stop all motion within 0.5 seconds, confirmed by PLC timestamp. Interrupt the safety light curtain — the machine must stop, not merely pause. Open the control cabinet door — the interlock must kill main power. Record all safety test moments as video frame grabs for the FAT report.

Running the Remote FAT: Equipment and Setup

The Zray factory preparation for a remote FAT includes:

• Three fixed IP cameras. Camera 1: wide shot of the complete machine from operator side. Camera 2: tight close-up on the forming station, capturing blank feed, folding, and glue application in a single frame. Camera 3: ejection conveyor showing each finished carton. All stream to a private feed with access control. Minimum: 1080p at 30 fps, latency under 2 seconds. The buyer can request the operator reposition Camera 2 to inspect any station.
• PLC data mirror. A secure VPN tunnel connects the Siemens S7-1200 PLC to a laptop running TIA Portal with screen sharing. The buyer views real-time diagnostics: servo torque, cycle time per station, glue pump pressure, error log with timestamps. Read-only — verification, not remote control. VPN connectivity is tested 48 hours before the FAT.
• Calibrated measuring station. A dedicated bench with proper lighting. A digital caliper (0.01 mm resolution, calibration certificate visible in frame) measures each of the 50 sample cartons. Every measurement is called out and simultaneously entered into a shared spreadsheet the buyer sees updating in real time.

The Buyer’s Checklist

• Ship 1,000 test blanks to Zray at least 10 days before the FAT date, with a dimensional drawing showing tolerances.
• Assign one engineer to monitor the live stream full-time. This person notes anomalies and nothing else.
• Prepare a punch list template: item number, description, severity (critical/major/minor), resolution.
• Record the entire video feed as evidence.
• Align time zones: overlap at least 4 working hours between Zray (UTC+8) and your team.

After the Remote FAT

The FAT report is issued within 24 hours: signed punch list, 50-carton measurement data, dry cycle PLC log (CSV), and video frame grabs of safety tests. This report becomes part of the shipment documentation.

The Santiago remote FAT identified two non-conformances: a KTP700 HMI substituted with a KTP400 without approval, and glue bead width of 1.8 mm against a 1.5 mm maximum. Both were corrected before shipment. Without the remote FAT, the HMI substitution would have been discovered only at installation — with no practical remedy short of air-freighting a replacement.