Buyer questions answered
Practical questions for specification and approval.
Each answer starts with the decision, then identifies the evidence or limitation that changes it.
Which results should be recorded during a weigh filler trial?
Record each consecutive net weight, the target setting, product and batch, pack tare method, hopper condition, operating rate, adjustments, stops, spills and incomplete discharges. A summary without the sequence can hide drift, refill effects or clusters of poor results.
Keep rejected or interrupted cycles in the trial record with a reason rather than deleting them. Note the reference scale used and whether weights were measured statically or by a downstream checkweigher. This allows the buyer to separate machine behaviour from the measurement method.
Why is one accurate fill not enough to prove performance?
One fill shows only that the machine produced one acceptable result. It does not show repeatability, drift, the effect of hopper refill, the behaviour of difficult particles or the time needed for the complete pack cycle. A useful trial therefore evaluates a consecutive series under representative operating conditions.
Selected results create an optimistic view. The sequence should include the start of the run, steady operation, a normal refill and any planned change in target or pack. If a result is excluded, the reason should be documented and agreed.
How do mean weight and standard deviation answer different questions?
Mean weight shows where the process is centred relative to the target or nominal quantity. Sample standard deviation describes how widely the consecutive results are spread around that mean. A high mean with a narrow spread may create avoidable giveaway, while a correctly centred mean with a wide spread may create under-target risk.
Minimum, maximum and range add context but are sensitive to the particular sample. The sequence plot is also useful because a single standard-deviation value may not reveal slow drift, alternating results or a step change after hopper refill.
How should product giveaway be compared?
For a defined sample, average giveaway is the mean net fill minus the chosen reference weight, multiplied by production volume when estimating mass over a run. Use the same reference and units for every candidate. Do not convert the result into cost unless the product cost basis is known and agreed.
A lower average fill is not automatically better if variation or under-target risk increases. Compare giveaway together with the distribution, reject policy and legal or customer requirements. The site’s giveaway calculator can help standardise the arithmetic without replacing a controlled quality assessment.
When should a weigh filler trial be repeated?
Repeat the trial when the product, pack, target, refill method, machine configuration or acceptance method changes materially, or when the original run did not reach stable representative conditions. A retest is also appropriate after corrective work that could affect the weighing or discharge path.
Do not combine unrelated runs into one distribution without identifying the change between them. If the machine is intended for several product families, retain a separate result set for each combination that changes flow, dose volume, fragility, dust or pack handling.
How should output and fill quality be reported together?
Report accepted finished packs per unit time alongside the corresponding weight distribution and operating conditions. A faster setting that produces more spills, rejected packs or unstable weights may not improve sellable output. The trial report should therefore connect rate, quality and operator workload.
State whether product refill, pack loading, closure handover and removal were included. If the trial uses an open test container instead of the real pack, label the result as a dosing test rather than a proven line-output figure.
