In-line Checkweigher

Short answer: An in-line checkweigher weighs every pack as it moves along the line and rejects any pack outside the weight limits you set. The configuration depends on the pack weight range, the accuracy required at your line speed and how packs arrive from the packing machine.

How it works

Packs arrive from the packer onto an infeed belt that sets the spacing between them. Each pack then passes across a weighing belt mounted on a load cell. The controller filters out vibration and belt movement, calculates the pack weight and compares it with the limits for the active recipe. Good packs continue on the outfeed belt. Packs that are underweight or overweight are removed by an air blast, pusher, flap or drop-down belt, usually into a lockable reject bin. Results are counted and can be stored or sent to a plant system.

The weigher is set up per product with its target weight, limits and pack length. A zero check between packs compensates for crumbs or dust on the belt, and a regular test with reference weights confirms the reading. Statistics such as average weight and standard deviation help you see whether the filler upstream is drifting before packs start failing.

Which configuration fits

Form	Suits	Watch out for
Single lane	Bags, pouches, trays, cartons	Packs must be evenly spaced
Multi-lane	Small sachets, stick packs, multi-lane packers	More complex setup and rejection
Combined with metal detector	Short lines, one-stop end-of-line inspection	Both units share downtime for service

Line layout matters: vibration from nearby machines and air drafts affect weighing, so the checkweigher needs a stable floor position.

What we need from you to quote

• Pack type, dimensions and weight range
• Weight limits and required accuracy
• Target speed in packs per minute
• Spacing and orientation of packs from the packer
• Reject method, confirmation and data recording requirements
• Whether a metal detector is to be combined
• Power, compressed air and cleaning method

Where it sits in a line

The checkweigher typically follows a VFFS packaging machine, premade pouch packing machine, tray sealer or liquid filling machine. It is often paired with a food metal detector and can send weight trends back to a multihead weigher upstream.