Machine repeatability
Can the configured machine deliver a consistent sequence with the defined product, settings, head and pack?
Measurement and acceptance
How should paste filling accuracy and fill weight be verified?
Define accuracy as a test method, not an unsupported percentage. State the product, temperature, target quantity, container, tare, sample sequence, machine settings and acceptance rule. A volumetric filler can be checked by mass, but density and temperature must be considered when mass is used to assess a volume dose.
Direct answer
A meaningful accuracy statement identifies what was filled, how it was measured and when the samples were taken.
Machine repeatability, process capability and legal packaged-goods compliance are related but different questions. A factory trial can show how a configured filler performs under stated conditions; the packer remains responsible for the production checking system, suitable measuring equipment, records and any legal obligations that apply to the finished goods.
Production control
Can the site detect drift, correct settings and release packs under normal batch, operator and environmental variation?
Pack compliance
Does the finished packing and checking system meet the applicable quantity, equipment and record requirements?
Test definition
Record the conditions that can change the result.
| Test input | What to record | Why it matters |
|---|---|---|
| Product condition | Batch, temperature, mixing history, aeration, settling and particle distribution. | Viscosity, density and chamber refill can change during the run. |
| Target and method | Nominal quantity, whether the machine doses by volume or another method, and whether checks are by mass, volume or level. | The measurement must represent the production requirement. |
| Container and tare | Container lot, empty-pack weight method, closure or lid inclusion and balance resolution. | Variable tare can hide or exaggerate fill variation. |
| Machine identity | Machine, dosing module, head, valve, nozzle, recipe and relevant utility settings. | Results are not transferable to an unidentified configuration. |
| Sample sequence | Priming, start-up, consecutive steady-state packs, planned pauses and end-of-batch samples. | Drift and restart behaviour may not appear in isolated samples. |
| Acceptance rule | Sample count, limits, actions on failure and who approves the result. | A result cannot be judged consistently without a pre-agreed rule. |
Volumetric dose checked by mass
When can weighing be used to verify a volumetric paste fill?
Mass checks are often practical, but the conversion between volume and mass depends on product density. If temperature, aeration, composition or settling changes density, a stable weight does not necessarily prove a stable volume and vice versa. Record the density basis and product condition used for any conversion.
Use the existing viscous-product accuracy guide for sequential checks and the sample trial guide for representative product conditions.
Tare control
Do not let empty-pack variation become a filler problem.
- Use an agreed tare method for the actual container lot.
- Confirm whether caps, lids or inserts are included in the check.
- Use measuring equipment suitable for the quantity and decision being made.
- Record units, resolution and calibration or verification status as required by the site system.
- Separate gross, tare and net values in the production record.
Controlled sequence
A practical paste filling verification sequence.
- Approve the protocol: define product, pack, target, method, sample count and limits before the run.
- Check the measuring system: confirm the scale or other equipment is suitable for the intended decision and the tare method is controlled.
- Record setup: identify the machine, head, product path, settings, utilities and product condition.
- Sample consecutively: include start-up, steady operation, restarts and the hardest normal condition rather than selecting only good-looking packs.
- Investigate patterns: compare heads, time order, hopper level, temperature and pauses before changing a general setting.
- Retest after correction: document the action and collect a fresh sequence under the same approved conditions.
UK packaged-goods boundary
The machine trial does not replace the packer’s legal quantity-control system.
UK Government guidance explains the minimum and average systems for packaged goods and the associated checking responsibilities. It also states that equipment used to weigh or measure packaged goods must be suitable and that records are required in defined circumstances. Review the current packaged-goods guidance and equipment and records guidance, then obtain application-specific advice from Trading Standards where required.
Need the filler and verification method reviewed together?
Send the product, target quantity, pack, proposed check method, sample expectation and target accepted output. Lancing can define what the machine trial can prove and what remains part of your site control system.
Buyer questions
Common questions about paste filling accuracy.
How many samples are needed to prove paste filling accuracy?
There is no universal sample count for every purpose. The protocol should reflect the decision being made, the number of heads, expected variation, run length and applicable quality or legal requirements. Consecutive samples are more informative than isolated selected packs.
Why can paste fill quantity drift during a run?
Possible causes include product temperature, aeration, settling, hopper level, incomplete chamber refill, valve leakage, seal wear, utility changes and container tare. Record the sequence and operating conditions before adjusting the whole machine.
When should a checkweigher or weight-feedback system be considered?
Consider it when every pack needs an automatic weight decision, when trend feedback is part of the control strategy, or when the line needs automated reject handling. The weighing range, pack stability, line speed and legal-metrology duty must be specified separately.
Can one accuracy percentage be applied to every product and fill size?
No. A percentage without product, quantity, dosing module, machine configuration, sample method and test conditions is not a complete claim. Request evidence for the actual application and intended acceptance method.