Hello,

I am currently working on seats for the automotive industry and I would like to detect the presence of a small plastic joint automatically. When this small joint is not present, another part of the mechanism is able to move a few millimeters. I thought of using a proximity sensor with contact to measure the position of this part with the joint and set it as a reference. Then, for each test, the part can be pushed from the opposite side of the sensor by a spring and the difference between the measure and the reference can be calculated.

Do such sensors exist? Is there another solution?

Thanks.

Vianney
 

There are lots of options; it's just a question of what accuracy do you actually need, and how much are you willing to pay.  One option is a laser rangefinder:
https://www.mysick.com/eCat.aspx?go=FinderSearch&;Cat=Gus&At=Fa&Cult=English&FamilyID=380&Category=Produktfinder&Selections=44127

This has the advantage of being tolerant of most material or surface properties.

TTFN
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Actually, I would like something really precise (to measure about 1mm), the probleme is that the object that moves is really thin (cf picture). Do you think a laser rangefinder could work? I also thought of a microswitch.

And I would prefer something not too expensive but that is not the most important.

Thanks.

• http://files.engineering.com/getfile.aspx?folder=19c13f6c-f0c0-493f-a30f-cf

No, don't use a microswitch unless robustness issues force you there.

I strongly suggest you get a sample into a lab and measure the force vs deflection curve with and without the missing part. Then decide on an appropriate pass fail criteria.

 

Cheers

Greg Locock


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Laser is light, so if it reflects, and is not transparent, there is no issue.

The Sick laser has resolution down to 0.05 mm

TTFN
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