Factory Acceptance Test (FAT) for Bagging and Palletizing Lines: A Practical Pre-Shipment Checklist

The most expensive problems on a new packaging line are almost never discovered at the factory - they are discovered three months later, on your floor, with your product in the hopper and your customers waiting. A factory acceptance test is the cheapest insurance against that outcome. Done properly, a FAT proves that a fully automatic bagging machine, its closing station and the downstream column palletizer actually run together at your tonnage, with your bags and your material, before anything is crated. This article sets out what to prepare, what to witness, and what to record before you sign the release.

What a FAT Is - and What It Is Not

A FAT is a witnessed run of the complete line at the manufacturer's works, against acceptance criteria agreed in advance. It is not a demonstration reel, and it is not the same as site acceptance testing (SAT), which happens after installation. The FAT proves the machines work; the SAT proves they work in your building with your utilities, your operators and your upstream supply. Both matter, but the FAT is where design and build errors are still cheap to fix.

Prepare Before You Travel

A FAT fails for logistical reasons more often than for mechanical ones. Agree the following in writing at least two weeks ahead:

• Test material: your actual product, in sufficient quantity for a continuous run. Running a substitute granule hides bridging, dust and weighing behaviour that will appear on day one at your plant.
• Consumables: your real bags, liners, pallets, stretch film and labels - including the pallet size and quality grade you will actually receive, not a premium sample.
• Acceptance criteria: target bags per hour, weighing tolerance, reject rate, bag closing integrity, pallet height and layer pattern.
• Utilities: available power, compressed air volume and pressure at the test bay, and whether these match your site.
• Duration: a short burst tells you little. Insist on a sustained run long enough to expose heat, drift and jamming behaviour.

Mechanical and Running Checks

Watch the line as a system rather than as separate machines. Feed should be stable from the surge hopper into the weigher; the bag magazine should present bags without double picks or mis-feeds; filling, closing and discharge should stay synchronised at the quoted rate; and the palletizer should build layers without gaps, overhang or bag deformation. If the line includes a bagging carousel, a bag attacher or a tubular reel bagging machine, run those stations at full speed too - they are frequent bottlenecks that only appear under load. For jumbo bag formats, the same discipline applies to a FIBC packing machine, where filling, liner handling and densification interact.

Weighing Accuracy: Test It Properly

Weighing is the criterion most often measured badly. Do not accept a single reading. Take a statistically meaningful sample of bags across the run - including the first bags after startup and the bags produced immediately after a pause - and weigh them on a calibrated check scale. Record the mean, the spread and the number of bags outside tolerance. Then repeat after a deliberate restart, because drift after stop-start is the failure mode that costs real money in giveaway. If your line uses net weighing, gross weighing or a combination, the method and the tolerance should be stated in the contract, and you can read more about the trade-offs in our guide to bagging weighing accuracy.

Bag Closing and Seal Integrity

A perfectly weighed bag that opens in transit is a claim waiting to happen. Inspect closed bags from the run: stitch density and thread tension on sewn closures, seam temperature and consistency on heat-sealed or pinch-top closures, and the absence of product in the seal area - trapped dust is the most common cause of weak seals. Drop-test a sample of filled bags from a realistic height and inspect the closure afterwards. If the line uses a automatic sewing machine, confirm that the closing station keeps pace with the filler rather than being bypassed during the demonstration.

Palletizing and Load Stability

Pallets fail in two ways: they fall apart in the truck, or they arrive leaning. Verify the layer pattern against the agreed drawing, check overhang and interlock, confirm pallet and slip-sheet handling, and inspect stack squareness at full height. If the line feeds a stretch wrapper or a truck loading system such as an automatic truck loading robot, run that interface as well - the pallet handover is where many end-of-line problems originate.

Controls, Safety and Documentation

Confirm that every emergency stop, guard interlock and light curtain actually stops the line, that the HMI alarms are labelled correctly, and that the recipe structure lets your operators change bag size or target weight without a programmer. Ask for the electrical and pneumatic drawings, the spare parts list with lead times, the maintenance schedule and the operator manual in your language. Finally, witness a full changeover: if switching bag size takes longer than the quoted figure, that is a design issue worth raising now rather than after installation.

Sign-Off: Record Everything

End the FAT with a written punch list. Every item should have an owner, a fix and a date, and anything that cannot be fixed before shipment should be tied to a retention payment or a defined post-installation commitment. Photograph the running line, keep the sample bags and the weighbridge records, and file them with the contract. When the equipment arrives, that file is what turns an argument into a straightforward task list.

Plan Your FAT With Us

Recens runs witnessed factory acceptance tests on complete bagging and palletizing lines with the customer's own product and packaging, and we publish the acceptance criteria before the run rather than after it. If you are specifying a new line, we will help you write the criteria and the punch list so the test proves something.

WhatsApp: +86 150 3816 6007 - send your product, bag format and target capacity and we will reply with a specification and budget price.

WhatsApp: +86 150 3816 6007 - planning a new packaging line? Share your layout and daily tonnage and we will suggest a complete bagging, closing and palletizing configuration.