Direct Answer
A factory acceptance test is where a buyer stops purchasing a specification and starts purchasing a machine. Run the equipment for a sustained, witnessed period at the contracted speed, on the buyer's own board or cup stock, and record output, waste, stoppage time and dimensional quality against limits agreed before the deposit. A test that only watches the machine move is entertainment. A test that produces signed raw data, a documented material balance and a punch list is protection. The protocol belongs in the purchase contract, not in an email the week before the visit, because that is the difference between an observation and a remedy. Buyers who write pass and fail thresholds first, and refuse to sign off until the punch list closes, avoid the expensive halfway service: a machine that arrives complete but not capable.
Opening Hook
The machine looked flawless on the video call, and on the day of the visit it ran for forty minutes at a comfortable speed and produced perfect cups. Three weeks after installation, at contract speed on the buyer's own stock, the sealing station began rejecting one cup in nine and the maintenance team had no baseline to argue from. The supplier had done nothing dishonest; nobody had written down what "capable" meant. The fix is cheap and unglamorous: define the test before the deposit, run it on your own material, log the numbers, and hold the balance payment until the punch list closes. At yoco-group, we hand buyers the test protocol at quotation stage because a machine is only as good as the evidence that ships with it.
What the Factory Acceptance Test Actually Decides
The FAT decides one question: can this machine make the agreed product at the agreed rate, repeatably, on the material the buyer will actually use.
| Test question | What it looks like in practice | Evidence produced |
|---|---|---|
| Capability | Sustained run at contract speed on buyer material | Timed output, waste count |
| Quality | Dimensions and sealing integrity sampled across the run | Measurement log, sample parts |
| Stability | Stoppage and adjustment events logged by cause | Downtime log with timestamps |
| Changeover | One size or format change performed by supplier staff | Changeover time record |
| Safety | Guards, interlocks and emergency stop demonstrated | Signed safety check sheet |
Notice that none of these entries is "the machine started". A capability test without a stopwatch and a waste bin is a demonstration. The distinction matters commercially because payments are usually staged, and the FAT normally releases the final pre-shipment instalment. If the buyer has not defined "pass", the supplier is entitled to interpret it, and the interpretation will be generous. Writing the thresholds into the contract converts a subjective impression into an objective event that either happened or did not.
Writing the Protocol Before the Deposit
The protocol is a short document, and its brevity is a feature. Five clauses carry most of the value.
| Protocol clause | What to specify | Why it matters |
|---|---|---|
| Material | Exact board or cup stock grade, gsm, supplier | The machine is validated on what you will run |
| Duration and speed | Minutes of continuous run at stated speed | Prevents a short, gentle demonstration |
| Measurements | Output, waste percentage, key dimensions, seal test | Creates comparable numbers |
| Acceptance thresholds | Pass limits written as numbers | Removes interpretation |
| Failure remedy | Rework, retest or payment consequence | Gives the clause teeth |
Buyers who have never written such a protocol can borrow the discipline from standard work practice: define the work, define the normal condition, then define the deviation. The Lean Enterprise Institute's standard work resources describe exactly that logic, and it transfers cleanly to a machinery acceptance clause, because a test is standard work applied to a supplier's floor rather than yours. The cost of writing it is an afternoon. The cost of omitting it surfaces months later as a capacity shortfall nobody can prove.
Data: ISO publishes machinery safety and quality management standards, including the ISO 9001 quality management family and the ISO 12100 machinery risk assessment framework, which define how equipment conformity and process control are documented.
Judgment: Tie the acceptance test to a documented standard rather than a verbal expectation, because conformity language gives the buyer a defensible vocabulary when a machine underperforms after shipment.
Source: ISO — Machinery Safety and Quality Management Standards (2024)
The Running Test: Materials, Output and Quality Sampling
The running test is the core of the FAT, and it should be long enough to expose thermal drift, wear-in and sealing variation.
| Sampling point | Time in run | What to record |
|---|---|---|
| Start-up | First 5 minutes | Reject rate during warm-up |
| Early steady state | Minutes 10–20 | Output per minute, dimensions |
| Mid run | Middle third | Seal strength samples, appearance |
| Late run | Final third | Drift in dimensions and rejects |
| Shutdown | End of run | Purge waste, restart behaviour |
Two practices separate a useful test from a useless one. The first is running on the buyer's material rather than the supplier's showroom stock, because board stiffness, moisture content and coating differ enough to change forming behaviour. The second is sampling across the run rather than at the end, because a machine can hold tolerance for ten minutes and drift by minute forty. Buyers should bring their own measuring instruments and their own stopwatch, and should be willing to write down numbers that contradict a comfortable narrative.
Where the buyer's product is a formed paper article, the same discipline appears in machine performance measurement, and it connects directly to how the line is later benchmarked in production. Buyers who want the full framework can read our guide to OEE on paper cup lines, which explains how availability, performance and quality losses are separated once the machine is in service.
Documents and Data You Should Not Leave Without
A machine ships with metal, and it should also ship with a file. The file is what a warranty discussion runs on.
| Document | Purpose | Check before signing |
|---|---|---|
| Signed FAT report with raw data | Baseline for future performance claims | Numbers match the log you kept |
| Declaration of conformity | Placing on market in the destination region | Correct legal entity and machine model |
| Electrical and pneumatic drawings | Maintenance and future modification | Revision number and date present |
| Spare parts list with part numbers | Procurement and interchangeability | Covers wear parts and proprietary items |
| Operation and maintenance manuals | Training and safe operation | In the buyer's language |
| Component test certificates | Pressure vessels, safety devices | Where the component class requires it |
The conformity document deserves emphasis because it is market-specific. A machine bound for a market with a mandatory machinery safety regime is placed on the market under that regime's rules, and the documentation is part of the product, not an optional extra. Buyers should ask which conformity route the supplier follows, what the declaration covers, and who signs it, and should compare that answer with the destination market's requirements before the machine is crated.
Data: UL Solutions provides product safety certification and testing services used across industrial equipment categories, documenting that a given product has been evaluated against defined safety requirements.
Judgment: Ask what has been evaluated and by whom rather than accepting a logo, because the scope of a safety evaluation is as important as its existence when the machine is installed in a regulated workplace.
Source: UL Solutions — Product Safety Certification and Testing Services (2025)
Safety Demonstration and Guarding at FAT
Safety checks are cheap to perform at the supplier's works and expensive to discover at commissioning.
| Safety item | What the test should show |
|---|---|
| Fixed guarding | Guards present, tool-fixed, not removable by hand |
| Interlocked doors | Machine stops when guard is opened |
| Emergency stop | Verified from each operator position |
| Reset behaviour | Restart requires deliberate action |
| Hot surfaces and pinch points | Labelled and shielded |
| Lockout provision | Isolation points identifiable and accessible |
The sequence matters: demonstrate the guard, then open it while the machine runs, then confirm the motion stops and does not restart on closing alone. A guard that is present but not interlocked satisfies a photograph and fails a workplace inspection. Buyers should record the check on the same sheet as the running test so the two are tied together, and should photograph nameplate data, guard positions and the emergency stop layout. Those photographs are the fastest way to settle a later question about what was actually delivered.
Data: The U.S. Occupational Safety and Health Administration maintains machine guarding requirements and guidance describing how moving machine parts must be protected to prevent operator injury.
Judgment: Treat guarding as a verifiable test item with a photographic record, because retrofitting interlocked guarding after installation costs more than confirming it before shipment.
Source: U.S. Occupational Safety and Health Administration — Machine Guarding and Workplace Safety (2025)
The Punch List and How It Protects the Balance Payment
A punch list is the mechanism that turns observations into obligations, and it works only if it is written and signed before the buyer leaves.
| Punch list element | Wording that works | Wording that fails |
|---|---|---|
| Defect | "Sealing station rejects 11% on 210 gsm board at 90 rpm" | "sealing not good" |
| Threshold | "Rejects below 3% sustained for 60 minutes" | "should be better" |
| Action | "Supplier to replace heating element and retest" | "supplier to look at it" |
| Owner and date | Named engineer, calendar date | "soon" |
| Evidence of closure | Retest report signed by both parties | Verbal confirmation |
The commercial logic is straightforward: the final instalment is the buyer's last leverage, and a punch list with a retest condition holds it in place. Two further rules keep the list honest. First, close items on evidence, not on promises, and refuse to accept photographs as substitutes for a retest where the defect is performance-based. Second, keep the same list through to site acceptance, so the commissioning visit starts from the open items rather than from a blank page. Our installation and commissioning checklist carries this logic forward to the buyer's own floor.
Data: ASTM International publishes mechanical testing and specification standards that give suppliers and buyers a shared vocabulary for describing test methods, tolerances and acceptance conditions.
Judgment: Write acceptance criteria in the vocabulary of a published test method where one exists, because shared method language removes the ambiguity that turns a defect claim into a negotiation.
Source: ASTM International — Mechanical Testing and Specification Standards (2024)
The Bottom Line
Agree the test before the deposit, run it on your own material at contract speed, log the numbers yourself, capture the conformity and parts documents, and hold the balance payment against a signed punch list. A factory acceptance test is not a courtesy visit; it is the buyer's only chance to test the machine while the money still talks.