Feeding technology

Feeding means bringing parts from a stock to a station in such a way that they can be processed there without searching: singly, in the right orientation, at the right time. It comprises storing, orienting, separating and metering.

For small parts this is done by vibratory feeders, step feeders and magazines. For large and heavy parts, feeding mainly means presentation: in containers, on pallets, in racks or on workpiece carriers.

A part whose position is known can be picked up in one movement with a simple gripper. A part lying anyhow in a container first has to be found, cleared and turned. That effort arises anew for every single part.

It is therefore worth preserving the order a part already had when it was made. Throwing parts into a mesh box after the press destroys position information that has to be recovered at the next station with time, effort or machine vision.

A hand-guided device forgives disorder – the operator sees where the part lies. Even so, presentation determines whether the device keeps the cycle.

When a handling device is felt to be too slow, the cause often lies not in the device but in the feeding. The operator re-grips, turns the part by hand, waits for the container change or walks round the pallet.

Anyone planning a workstation therefore treats feeding, device and set-down as one system. The cheapest improvement is often not a technical one: a different container, a layer pad with moulded nests, a lift table under the pallet.