Long distance inductives keep the sensor out of harm’s way

When a manufacturer of automotive switches which need to ensure the presence of a metal washer in its assembly, it turned to Contrinex.

The assembly of electrical switches includes a dark metal, wave-shaped washer which ensures a tight mechanical switching action and well-sealed switch assembly. The assembly of the switches is fully-automated and the typical automotive industry quality expectation is that parts are 100% verified.

There is a need therefore to ensure that no switch can be assembled without the washer - The presence of the washer needs to be checked immediately after it is inserted and before the switch assembly continues to the next stage, rejecting the part, or suspending the entire production process.

The switches are small because they are used in vehicles, and therefore the automated assembly line to manufacture them is intricate with lots of moving parts and limited space to accommodate sensors. The uneven surface and dark colour of the wave-shaped washer and the congested area within the assembly line made it difficult for detection with a photoelectric sensor, whilst detecting the metallic washer using an inductive sensor was more flexible.

The washer is inserted early in the assembly of the switch, at the third station of 15. To guarantee the quality of the assembled switch, the presence of the wave washer is checked before the workpiece passes to the next assembly station.

Space within the machinery is very limited, and whilst an inductive offers flexibility with its location, a sensor not larger than M18 was desired. Because of the large number and speed of moving parts within the system, it was considered wise to mount the inductive sensor at a safe distance from the moving workpiece assembly.

A Contrinex ‘500 Series’ inductive sensor is used because of its long sensing range and its ability to reliably sense the small amount of metal within the wavy washer. The patented Condist technology is designed to provide excellent sensing stability against environmental influences, especially temperature change, which enables in this instance a non-embeddable M18 sensor with a 20mm sensing distance.

The sensor looks down at the workpiece carriers and semi-assembled switches as they pass below on an automatic conveyor line. If the sensor detects a missing washer, the control system activates a solenoid to prevent the workpiece carrier advancing to the next station, whilst an alarm is sounded to alert the operator.

Being able to locate the inductive sensor well away from moving parts protects it from mechanical damage and avoids a frequent cause of downtime. Its excellent reliability ensures end-product quality and eliminates a potential source of customer complaints.

Contrinex - PLUS Automation

Lyth Farm
Lyth Lane

0121 5822258



More news
Farnell, NXP and Doulos present new Industry 4.0 webinar
Farnell has announced the launch a new global webinar covering ‘Automation and Edge AI for Industry 4.0’ in partnership with the Element14 Community, NXP and Doulos on Wednesday 24 August.
Needle valves receive ISO 15848-1 Class C low emissions certification
Parker Hannifin is unveiling a series of valves tested to ISO 15848-1 Class C, a standard that sets out the measurement, test and qualification procedures for fugitive emissions from industrial valves.
Thorite offers same-day hydraulic hose assembly service
Air and fluid power specialist Thorite has launched a same-day hydraulic hose assembly service to help customers reduce downtime and control costs.
Festo demonstrates bioreactor for large-scale photosynthesis of algae
Festo presented the PhotoBionicCell research project at the Hannover Fair – a bioreactor that enables the efficient and large-scale photosynthesis of algae.
Actuator increases accuracy and productivity of bagging machine
When end users of a precision bagging machine started using economical bags with inconsistent sizes, this impacted accuracy and productivity of the bulk bagging process.
World’s first e-chain made of 100% recycled material
Conserving resources and extending the product life cycle are the objectives of the new Igus cradle-chain E2.1.CG, which the company says saves 28% CO2 versus current e-chain production.
Siemens Congleton factory accelerates towards net zero goal
Siemens’ Congleton factory is on track to achieve carbon neutrality this year – eight years ahead of its original target.
Full speed ahead for a custom conversion
A vision for a customised camper van led Leigh McCarron to Minitec UK. Working together to Leigh realise his dream, Minitec advised on the choice of profile that would turn an old transporter vehicle into a customised ‘king of the road’ camper van.
Inductive sensors prove a ‘jack of all trades’ in bridge construction
When a specialist assembler of prefabricated bridges needed a rugged sensor for position sensing on its hydraulic cylinders, it turned to Contrinex.
Digital tools to support engineering design
Nowadays in engineering, digital tools are an essential part of a design engineer’s daily life and any tools that are available freely are naturally an added bonus.

Login / Sign up