Can a checkweigher automatically correct a volumetric filler?

A checkweigher inspects mass after filling. A volumetric filler meters a defined volume during the dose. Connecting them creates a control loop only when an agreed quantity change can be commanded, applied and acknowledged. A checkweigher display, reject signal or network connection alone does not provide that capability.

A mechanically adjusted piston filler may need operator adjustment or an engineered upgrade. Do not assume an HMI-controlled model accepts external dose commands. Ask Lancing to review the actual controller and supplier interface documentation alongside the automatic filling-line configuration.

Why can a bottle be heavier without containing more liquid?

Gross bottle weight includes the container and any closure or label already fitted. Changes in those components can move the measured weight without changing the liquid dose. Product density also affects the relationship between mass and volume. Check tare variation, the measurement point and product conditions before interpreting a weight trend as a volumetric-filler error.

Use the weight-to-volume verification method where density is known under the relevant conditions. For packs declared by weight, agree a net-quantity method. For packs declared by volume, agree how volume is established. A feedback target and a legal acceptance rule are not automatically the same setting.

Will feedback make every fill more repeatable?

Feedback can address a persistent change in the process average; it does not necessarily reduce the spread of individual fills. Air in the product, variable feed, worn parts or intermittent nozzle behaviour need their own investigation. Moving the target repeatedly in response to isolated outliers can make a stable process less stable.

Mettler-Toledo’s checkweighing guidance distinguishes tare variation from the filler’s contribution to the distribution. Record the mean and the spread separately using the accuracy and repeatability guide. Reject handling should continue independently of whether a result is eligible to influence a correction.

Why must the controller wait after changing the fill setting?

Packs already travelling between the filler and checkweigher were produced at the old setting. Their weights cannot demonstrate the effect of a new correction. Feedback needs a defined delay or tracked pack count before it evaluates the next adjustment; otherwise the controller may continue correcting a change that has not yet reached the scale.

Include conveyors, capper delays and accumulation in that assessment. A fixed delay that works during uninterrupted production may be wrong after a stoppage. Manufacturer feedback-control guidance explains the need to allow a setting change to take effect before sending another correction.

Can the checkweigher correct one weak filling head?

Head-specific correction requires reliable association between each weighed pack and its filling head. A merged conveyor stream does not automatically retain that identity. Establish pack order or another validated tracking method, including removed bottles, gaps and restart conditions. Without dependable attribution, review the heads separately rather than assigning an aggregate error to one head.

Use the multi-head assessment procedure before designing individual corrections. A common offset may hide one high head and one low head even when the overall mean appears acceptable.

A useful factory acceptance test follows controlled changes through the whole chain: measured pack, trend decision, command, acknowledgement and subsequent packs. Keep an independent reference check. Separate an advisory-only trial from an automatic-control trial so the evidence shows which function actually operated.

• Compare accepted results before and after a deliberately bounded, authorised setting change.
• Challenge missing or duplicated pack identity, conveyor stops and accumulation changes.
• Verify that recipe mismatch and stale or invalid data do not silently drive new corrections.
• Check that rejected packs are managed as specified even when their weights are excluded from correction logic.
• Record who can enable feedback, change limits and restore the previous approved recipe.

Does automatic filler feedback prove packaged-goods compliance?

Automatic feedback alone does not prove packaged-goods compliance. The applicable quantity system, checking equipment, sampling or inspection method, limits and records still need to be appropriate. A displayed average does not establish that every applicable requirement has been met. Confirm the actual product and packing method with the responsible quality team and, where needed, Trading Standards.

See GOV.UK guidance on packaged goods. This page is a control-system specification guide, not a legal certification or a claim that a particular Lancing model already has feedback functionality.

Send the filler and checkweigher identities, container/tare information, product density conditions, layout, controller interface and required quantity-checking method. Use the FAT and SAT checklist to agree what must be demonstrated.