Direct answer
Difficult parts should be assessed by what they do together in bulk. Hooks and coils can tangle; cups and rings can nest; light plastics can cling through static; rubber can stick; oil can change friction; cosmetic surfaces can mark. The right route separates that behaviour without creating a new failure at the hand-off.
Observed behaviour comes before feeder choice
| Observed behaviour | Check first | Routes that may merit trial |
|---|---|---|
| Tangling or hooking | Interlocking geometry, wire ends, bulk depth, oil and loading method. | Controlled elevation, shallow bulk presentation, separation tooling or staged replenishment. |
| Nesting or stacking | Cup geometry, diameters, flexibility, vacuum effect and contact area. | Mechanical denesting, air assistance, controlled recirculation or alternative presentation. |
| Sticking or clinging | Static charge, tack, oil film, humidity, material pairing and contamination. | Surface change, ionisation where appropriate, controlled contact, flexible presentation or cleaning controls. |
| Overlap or doubles | Part thickness, track width, queue pressure, sensor position and escapement timing. | Singulation tooling, vision verification, queue control or revised final release. |
| Marking or damage | Drop height, contact points, recirculation, speed, finish and coating compatibility. | Gentler elevation, low-marking surfaces, fewer recirculations or non-contact verification. |
Springs and wire forms that hook together
Compression, extension and torsion springs can form temporary chains or knots when bulk depth, oil and handling motion encourage engagement. More agitation can make the problem worse. Review loading quantity, wire ends, free length, coil diameter and the most entangled credible condition.
See the dedicated Sortation Solutions application guidance for springs and wire forms.
Cups, washers and parts that nest or stack
Concave components may telescope; thin washers may overlap; mouldings can lock together through draft or surface contact. A trial should record how nests form, whether they separate repeatedly and whether the chosen rejection method damages or starves the feed path.
Tacky rubber, oily parts and static-prone plastics
O-rings, seals and soft components can roll, deform, overlap or stick to each other and the track. Lightweight mouldings may cling through static, while oil can either lubricate movement or create adhesion. Trial parts in the real production condition and define any cleaning, ionisation or surface-control assumptions.
Related application detail: O-rings, seals and gaskets and plastic moulded components.
Preventing cosmetic marking and damage
Map every contact point, drop, reject and recirculation. A surface that works for one finish may abrade, scuff or contaminate another. The acceptance method should inspect the agreed cosmetic zones after a production-representative run, not only the first few parts.
Supplier, batch, cavity and finish variation
A feeder proven on one easy sample can fail when flash, burr, mould release, material, coating or dimensions move within the normal production range. Include the worst credible supplier, tool cavity, batch and finish combination in the sample set and record which limits were actually tested.
Compare feeder routes with an agreed trial
Vibratory tooling, step feeding, centrifugal handling, flexible presentation and vision inspection solve different parts of the problem. The trial should define the accepted hand-off, sustained rate, allowed interventions, reject behaviour, surface condition and downstream call pattern.
Prepare the evidence with the component trial and FAT checklist, and size the demand using the rate and buffer planner.