Piece size and shape
Use the largest, smallest and awkward pieces in the trial. Long or interlocking parts may bridge even when a small hand sample appears free flowing.
Product-path assessment
Hard components behave differently from food products even when they flow freely.
Fasteners, moulded parts, pellets and similar products can bounce, nest, overlap or strike contact surfaces repeatedly. A suitable machine must create controlled portions without jamming the feeder, damaging the component or allowing pieces to lodge in the outlet or pack opening.
Bounce and retained product
Hard pieces can rebound from steep surfaces or remain in corners. Observe the full discharge rather than relying only on the final weight reading.
Pack opening and support
The outlet must fit the container opening and the pack must be supported so the dose is not lost through movement, splash or rebound.
Technology route
Combination weighing is useful where multiple portions improve target selection.
A combination or multihead weigher can be appropriate when the product divides into repeatable portions and the target is best achieved by selecting several hoppers. A linear system may be simpler where output is lower and the product feeds predictably. The technology comparison guide explains the difference.
| Risk | What to inspect | Acceptance evidence |
|---|---|---|
| Nesting or bridging | Feed trays, hopper openings, chute transitions and outlet | No persistent blockage across representative pieces |
| Component damage | Drop height, collision points and sharp transitions | Before-and-after sample inspection and reject criteria |
| Wear or noise | Repeated impact on contact surfaces and support structure | Observed operation and maintenance plan for the real product |
| Pack loss | Opening size, pack support and discharge timing | Finished packs without spill or trapped product |
When weighing may not be enough
If the order requires an exact piece count rather than a controlled net weight, a dedicated counting or vision method may need to be considered. The acceptance requirement should make clear whether weight variation is acceptable and how under-count or over-count risk will be managed.
Cleaning and segregation
Non-food parts can carry oil, swarf, dust or mould-release residue. Define whether the machine is dedicated, how retained product is removed and how cross-contamination between component types will be prevented.
Sample trial
Test normal production pieces, not only a selected demonstration sample.
Provide a sample that includes the normal range of dimensions, finishes and batches. Record weights, output, blockages, damage, retained pieces and recovery after a stop. The test should use the actual pouch, jar, box or container opening where possible.
Application review
Send the component range, target weight and pack opening.
Lancing can review the sample and identify whether combination weighing, linear weighing or another handling method is the practical starting point.
Discuss the applicationBuyer questions
Frequently asked questions about this application.
Can screws and fasteners be filled by weight?
Yes, where the relationship between weight and acceptable quantity is suitable and the parts feed and discharge reliably. Exact-count requirements may need a counting method.
What samples should be supplied?
Supply the normal range of part sizes, finishes and batches, including pieces most likely to nest, bridge or bounce.
Can hard parts damage the machine?
Repeated impact can affect contact surfaces and noise, so product geometry, drop height and wear points should be reviewed during the trial.
Can the weigher feed a pouch machine?
It can be integrated where the pouch is confirmed open and ready before discharge and the outlet suits the pack opening.
Related guidance
All guides