Checkweigher Requirements in a Food Production Line: When Is One Mandatory?

A checkweigher weighs every pack as it moves and rejects any outside the limits. On many sites installing one is not a suggestion but a requirement, yet that requirement does not come from a single source and its roots are worth understanding.

Four sources of the requirement

• Net-quantity regulation: prepackaged goods must deliver the declared quantity. Common reference rules (such as EU Directive 76/211/EEC or OIML R 87, which many countries follow) set the average content and the permitted shortfall of individual packs. In Iran, legal metrology and labelling requirements are set per product group by the relevant authorities; check the legal reference for your own product.
• Customer and retail demands: retail chains and export customers usually ask for documented weight control when assessing suppliers.
• Quality standards: standards such as BRCGS and IFS contain clauses on quantity and weight control and on calibration of measuring equipment. A checkweigher is the usual way a packing line answers them.
• The cost of giveaway: if the filler is set well above the label weight to be safe, the difference on every pack becomes a heavy cost at volume. Accurate measurement lets you bring the average close to the permitted weight.

Which lines need one?

Wherever product is sold in discrete packs with a declared weight: pouches and bags, tubs, cartons, vacuum packs, cans and plastic containers. Bulk product weighed by a hopper or silo does not need one. If product is portioned before packing by a multihead or volumetric filler, the checkweigher is the final verification after it.

Records an auditor expects

• a weight-control procedure: permitted range, sampling frequency and responsible person
• test records using reference weights or reference packs at the start of shift and at product changeover
• calibration certificates for the scale and the reference weights
• statistical weight reports (mean, standard deviation, number rejected)
• corrective action when the mean drifts out of range, such as re-adjusting the filler

A decision checklist

Before buying, answer these: does your pack carry a declared weight? Does a customer or standard require weight records? Does your filler show a visible spread between packs? What are your line speed and pack weight? A yes to the first two usually means a checkweigher is part of your line's requirements. For site conditions, see technical requirements for checkweigher installation.

Related articles

• Industrial Checkweigher (Product Weight Measuring Machine)
• Checkweigher and Metal Detector Placement on a Packing Line
• How to Choose an Industrial Checkweigher: Weight, Speed, Accuracy and Reject System

Conclusion

A checkweigher protects you from complaints and penalties and also reduces giveaway cost. Send us your pack and line-speed details and we will propose a suitable configuration. For choosing a model, read how to choose an industrial checkweigher.