A factory acceptance test is a commercial boundary, not an inspection
Money changes hands when a machine ships, and the acceptance test is where both sides agree on what “working” means. A circular knitting machine factory acceptance test supplier quote that treats testing as an afterthought hands the risk to the buyer. A quote that names the test protocol, the conditions and the evidence gives the buyer a document to sign against. The two look similar on price and behave very differently when a defect appears six months later.
The test happens before the machine leaves the factory. Nothing about it proves the machine will knit well in a humid mill on a dusty floor with a different yarn supplier. What it does prove is narrower and more useful: the machine is built to the agreed configuration, it runs at the agreed speed, its safety functions respond, and its documentation matches the build.
What a factory acceptance test proves, and what it does not
Factory acceptance testing confirms identity, configuration, function and documentation. It does not confirm long-term wear, local power quality, site humidity, operator skill or the fit of a future yarn. Buyers who expect a factory test to guarantee production performance are asking the wrong document to carry the risk.
Split the two stages in the quote. The factory acceptance test (FAT) verifies the machine as built and packed. The site acceptance test (SAT) verifies installation, utilities, grounding and a production trial at the destination. A supplier that quotes one combined “acceptance” line is usually hiding where the responsibility for rework sits. Two named stages with separate sign-off keep the responsibility visible.
Agree the test conditions before the machine is built
A test protocol written after the machine is finished tends to describe whatever the machine already does. Write the protocol into the purchase order. The quote should state the yarn to be used, the fabric structure, the gauge and diameter, the target speed, the run duration and the tolerance on each measured value.
Ambiguity hides in pleasant phrases. “Reasonable speed” and “good fabric” are not test conditions. A defensible protocol names the machine model and serial number, the exact yarn count and composition, the fabric structure, the speed setpoint in revolutions per minute, the run length and the acceptance range for each parameter. If the buyer cannot state the yarn, the supplier cannot state the result, and the test becomes a demonstration.
Machine identity and configuration freeze
Before the test starts, freeze the configuration. List the model, serial number, cylinder diameter, gauge, feeder count, feeder type, take-down system, controller revision, motor type and any option fitted for this order. Photograph the nameplate, the control cabinet, the feeder ring and the fabric take-down. The photograph set becomes the reference if a question arises after shipping.
Configuration drift is a quiet problem. A machine built with one controller firmware revision and shipped with another, or fitted with substitute parts because an original was out of stock, can pass a casual test and still differ from what the buyer agreed. A frozen configuration list makes that substitution visible and turns it into a decision instead of a surprise.
Reference benchmarks used during a factory test
The values below come from Aisunny’s published technical-specifications database. They are reference benchmarks for structuring a test discussion, not universal thresholds. The buyer and supplier must set the actual acceptance range for the specific machine and order.
| Reference benchmark | Published value | Typical use in a FAT protocol |
|---|---|---|
| Maximum speed factor | Up to 1200 (diameter in inches × RPM) | Frames the speed range to be tested and recorded |
| Energy efficiency | IE3 motors, 15–20% lower consumption | Basis for an optional power measurement |
| Noise level | < 80 dB at maximum operating speed | Comparable sound-pressure reference at the test position |
| Vibration control | Cast-iron base with dampening pads | Frame the vibration check method and location |
| Cylinder hardness | HRC 58–62 after induction hardening | Reference for a hardness spot-check on cylinder parts |
| Cylinder trick tolerance | ±0.01 mm | Dimensional reference for cylinder-related checks |
A number in a table is not an acceptance criterion until the two parties assign it to a test. Ask the supplier to convert each relevant benchmark into a measurable instruction: where to measure, with what instrument, at what speed, and what result passes. If the supplier cannot describe the method, the benchmark was decoration.
The FAT protocol as a buyer-facing table
Compare competing quotes by forcing each supplier onto the same rows. A short protocol that everyone answers beats a detailed protocol that only one supplier understands.
| Protocol item | What the quote should commit to | Evidence produced |
|---|---|---|
| Machine identity | Model, serial, configuration list | Signed configuration sheet |
| Test yarn and fabric | Yarn count, composition, structure | Yarn lot record and fabric sample |
| Speed test | Setpoint, hold time, stability | Speed and time log |
| Output check | Production rate over the run | Output record or counter log |
| Fabric quality | Defect limits and inspection method | Inspection report with the sample |
| Safety functions | Emergency stop, guards, interlocks | Signed function test list |
| Controls and alarms | Start, stop, alarm and fault response | Fault simulation record |
| Noise and vibration | Method, position, reading | Measurement record where agreed |
| Documentation | Manual, drawings, revision list | Document pack with revision |
| Punch list | Open items, owner, due date | Punch list with sign-off |
Safety, controls and alarms need observable tests
A safety function that is not tested is a claim. The FAT should exercise the emergency stop, the guard interlocks and the restart-prevention logic, and it should record the observed response, not the word “passed”. Where the machine includes an electronic control system, run a fault simulation and confirm that the alarm appears, the machine behaves as designed and the event is logged.
Test the control interface as a production tool. Confirm that the operator can recall a recipe, change a parameter within limits, and that the machine rejects an out-of-range entry. Confirm that a power interruption produces a defined state on restart. These checks cost an hour and prevent a week of confusion during commissioning.
Where the order includes a controller replacement or a drive change, the controller replacement compatibility quote checklist sets out the compatibility questions that a factory test should confirm before shipping. If a take-down system is part of the scope, the take-down roller retrofit cost checklist covers the drive, pressure and fabric-roll points to include.
Output and fabric evidence decide the argument
Speed alone proves little. The machine must produce fabric that meets the buyer’s quality expectation at that speed. Agree a defect inspection method before the test, whether that is a defined length inspected against a defect list, a set of limits on visible faults, or a comparison against an approved reference sample.
Keep samples. A signed fabric sample from the test, labelled with yarn lot, structure, speed and machine serial, settles most later disputes. Store it with the test record. A photograph of fabric on a screen is not a sample.
The documentation pack and the warranty start point
Acceptance and documentation travel together. The quote should state which documents ship with the machine and in which language: operating manual, maintenance schedule, electrical drawings, spare-parts list with part numbers, controller parameter backup and a troubleshooting guide. The spare-parts repairability and service handover documentation framework describes the records that keep a machine serviceable after the supplier’s engineer leaves.
Define when the warranty starts. Common options are on dispatch, on arrival, or on successful site acceptance. The choice matters. A warranty that starts on dispatch can expire before the machine is installed if shipping or customs delay the delivery. A warranty that starts on site acceptance ties the clock to the moment the machine is actually ready to run.
Punch list, site acceptance and handover
Finish the factory test with a punch list, not a handshake. Every open item gets an owner, a description and a due date. Minor items may ship, but each one should be logged and closed with evidence.
Site acceptance closes the loop. After installation, retest the safety functions, confirm utilities and grounding, run the agreed yarn and record the first production output. Only then should the final acceptance be signed. A handover pack that includes the configuration list, the test records, the fabric sample, the punch list and the document set gives the maintenance team a starting point instead of a mystery.
If the factory test is part of a larger purchase decision, the ITMA ASIA + CITME 2026 buyer checklist frames the supplier questions to ask before and during the November 2026 Shanghai exhibition, and a circular knitting spare parts RFQ template keeps the parts side of the same order structured.
Frequently Asked Questions
Q: Should the FAT and SAT be in the same quote line?
A: No. Keep them separate. The factory test verifies the machine as built, and the site test verifies installation and a production trial. Separate lines keep the responsibility for rework visible and prevent one stage from hiding behind the other.
Q: Who writes the test protocol, the buyer or the supplier?
A: The buyer should propose the protocol and the supplier should confirm feasibility. A supplier-written protocol describes what the machine already does. A buyer-written protocol states what the order requires. The negotiation between them is the useful part.
Q: Can a factory test guarantee production output in my mill?
A: No. It confirms the machine runs at the agreed speed and produces compliant fabric under the agreed conditions. Site humidity, power quality, operator skill and yarn variation all sit outside the factory test.
Q: What should happen if the machine fails a test item?
A: The item goes on the punch list with an owner and a due date. Major failures should block dispatch until corrected. Minor items may ship with a documented closure plan. Never accept “will fix on site” without a written owner and date.
Q: How long should a factory acceptance test run?
A: Long enough to reach the agreed speed and inspect a meaningful length of fabric, often several hours. The duration should be written into the protocol, not decided on the day. A ten-minute demonstration is not a fat.
Q: Does the warranty start at dispatch or acceptance?
A: Ask for it in writing. Starting at site acceptance protects the buyer when shipping or customs delays delivery. Starting at dispatch protects the supplier’s cash cycle. Both are negotiable, so make the choice explicit in the quote.
Q: What documents should ship with the machine?
A: At minimum an operating manual, maintenance schedule, electrical drawings, spare-parts list with part numbers, controller parameter backup and a troubleshooting guide, in a language the operators read.
Conclusion
A factory acceptance test turns a machine purchase into a set of checkable claims. Write the protocol into the order, freeze the configuration, test the safety and control functions with observable results, keep the fabric sample and the document pack, and split site acceptance from the factory stage. The quote should name all of it. A supplier who will not commit the test conditions in writing is telling you where the risk will land.
References
Confirms the official 20–24 November 2026 Shanghai dates that frame pre-event supplier comparison work.
Provides the official starting point for machinery compliance and conformity obligations referenced in acceptance planning.
Official legal text underpinning safety and documentation expectations for machinery placed on the EU market.
Defines terminology, principles and methodology for machinery risk assessment used to structure safety test items.
Reference for the quality-management framework a supplier cites when documenting inspection and test records.
June 2026 signal on mill investment in automation and commissioning-ready machinery.