Solutions

The challenge

A spring cannot be checked on dimensions alone. What determines its function is the force it develops at a given length, or the change in that force between two working positions. Two springs with rigorously identical dimensions can show very different rates depending on the heat treatment applied, the wire grade used or the quality of stress relieving, which means that dimensional inspection, however well executed, guarantees nothing about behaviour in service.

Conventional methods therefore impose an uncomfortable compromise. A laboratory bench offers the accuracy required but remains slow, costly and far from the production line, which restricts inspection to a few parts per batch. A manual check at the workstation, by contrast, is quick but depends entirely on the operator's technique and judgement, with no record and no possibility of statistical monitoring.

The solution

The METRO F2 and F3 displays measure force and position at the same time, so the load is recorded at exactly the required length rather than at an approximate position estimated by the operator.

You program a complete inspection sequence: load to the first length, record the force, continue to the second length, record again, then calculate the spring rate automatically. Conformity is assessed without intervention, with an immediate visual verdict on screen and an audible alarm whenever tolerances are exceeded.

Statistics built up across the batch finally give an overall view of production, making it possible to see a drift developing gradually and to correct the process before it produces parts outside tolerance.

The benefit for the customer

Inspection moves out of the laboratory and onto the shop floor, at a pace compatible with production. Sorting becomes objective and repeatable, whoever is at the workstation. Above all, the speed of the check allows a far higher inspection frequency, turning an occasional verification into genuine process control.