Agree the boundary
State whether the test covers only the filler discharge or the complete line through capping, labelling, inspection or packing.
FAT and SAT decision criteria
What Is a Good Pack in Filling Machine Acceptance?
A good pack is a finished container that meets every agreed acceptance condition, not merely one with the correct fill quantity. The definition can include quantity, neck and exterior cleanliness, container condition, closure or downstream acceptance, coding or labelling where in scope, and traceable handling of rejects. It should be written before the test so output is measured as accepted packs rather than every cycle the filler attempts.
Define pass and reject conditions
A line-output test is meaningful only when everybody counts the same result.
Use observable conditions and identify which machine or process owns each reject.
| Acceptance area | Example decision question | Evidence |
|---|---|---|
| Filled quantity | Does the pack meet the agreed measurement and tolerance method? | Individual results linked to time, filling head and recipe. |
| Neck and exterior cleanliness | Is product absent from surfaces that affect closure, label or presentation? | Visual inspection under an agreed sampling method. |
| Container condition | Is the pack upright, undamaged and free from deformation caused by handling? | Reject record and photographs where a recurring mechanism needs investigation. |
| Downstream acceptance | Does the pack transfer, cap, code, inspect and label correctly where those operations are in scope? | Finished-pack result and fault/reject log across the agreed line boundary. |
| Traceability | Can an outlier or reject be linked to its sequence, head and operating event? | Time-stamped record, batch reference and machine observations. |
| Restart behaviour | Are packs after a normal stop, refill or changeover accepted under the agreed rule? | Separate start/restart samples rather than hiding them in the steady-run average. |
Count good output, not attempted cycles
A machine can cycle quickly while producing fewer accepted packs.
Separate planned stops, machine faults, upstream starvation, downstream blockage and quality rejects.
Agree the sample rule
Define whether every pack is inspected or whether a sampling plan applies, and how an unmeasured pack contributes to output.
Record rejects by cause
A single reject total hides whether the problem is quantity, drip, container handling, closure, label or another interface.
Retain event context
Record normal operator actions, refills, stops and recovery so the result shows sustainable production rather than an ideal uninterrupted window.
Clear answers
Questions buyers ask about this subject
The answer depends on the product, pack and operating conditions, so the relevant variables should be recorded rather than assumed.
Who should define a good pack before FAT?
The buyer should define the required finished-pack result with input from production, quality and engineering, while the supplier confirms what can be demonstrated within the agreed machine and test scope. The definition should be approved before FAT samples are run so acceptance does not change after the results are visible.
Is a pack good if the fill quantity is correct but the neck is wet?
Not when a clean neck is part of the agreed pack requirement or when the wet surface can affect capping, sealing, labelling, hygiene or presentation. Quantity and cleanliness are separate acceptance conditions. The test should record the wet-neck reject and investigate nozzle shut-off, container position, product behaviour and transfer rather than counting it as good output.
How should start-up and restart packs be treated?
Start-up and restart packs should be identified and assessed under a rule agreed before testing. They may be included, sampled separately or treated as controlled process waste, depending on the requirement. Hiding them by beginning the timed run only after perfect steady operation can overstate the production result and leave recovery behaviour untested.
What sample size should be used for acceptance?
The sample size should be agreed for the project and linked to the decision being made, the number of filling heads, the run duration, the expected sources of variation and the measurement effort. There is no defensible universal number for every filler. The plan should include enough sequential data to identify head differences, drift and event-related outliers.
How should rejected packs be recorded during an output test?
Record each reject with time or sequence, filling head where applicable, reject reason and the event around it. Separate quantity, drip, foam, container, closure and downstream causes. This allows accepted output to be calculated and prevents an upstream starvation event from being confused with a metering fault or a quality reject.
Continue your specification
Related liquid filling guidance
Use the next guide that matches the unresolved part of the application.
FAT and SAT acceptance
Plan staged evidence for the configured machine and installed line.
Output and speed guide
Measure sustainable accepted production rather than isolated cycles.
Accuracy guide
Define the quantity test and interpret bias, variation and outliers.
Discuss the application with Lancing
Send the product, container, target quantity and production context so the filling method and trial scope can be reviewed.