Hi All,

I'm searching for a proximity sensor capable of detecting the compression of a spring metal, which is situated within a plastic enclosure. However, I require the sensor to be positioned outside the enclosure while still being able to detect the metal through the plastic. i need a sensor effectively detect metal beyond the plastic barrier.

Please see the attachment.

I have tried inductive and capacitance proximity sensors but no success

Thank you

 

What material is the spring made of?

I'm imagining the spring is coiled, and something either compresses it or releases it (allows it to expand)?

How is the spring compressed or released? What is the material the is doing the compressing or the releasing?

Are you trying to detect the presence of a spring with the position of the switch (such as when it's released and expands), or an "absence" of the spring (such as when it is compressed below the face of the switch) inside the switch?

Are you sure the switch is in the correct position? (Sorry; I have to ask.)

Have you spoked with proximity switch vendors or manufacturers, or are you just trying to find one on the World Wide Web to purchase? Because many sensor suppliers represent multiple manufacturers and a good salesperson (ideally, an application engineer) would be able to, with the information above, be able to recommend a switch or possible even recommend another vendor/manufacturer you can try.

One last thing, some proximity switches have high leakage currents which can make it appear as if there is metal near the face of the switch at all times, because some monitors (PLCs, PACs) have to have a lower leakage current to sense the presence or absence of metal.

 

An application engineer that sells these products should be able to help you, otherwise please provide more details: Are you after a digital signal to indicate the spring is compressed or and analog signal to indicate the degree of compression? What is the distance from outside of the plastic enclosure to the spring? What are the dimensions of the spring when compressed and uncompressed? What is the location of the spring when uncompressed, is it near the switch? Probably easier to provide a drawing showing the different states you are trying to detect.

 

Hi All,

I'm searching for a proximity sensor capable of detecting the compression of a spring metal, which is situated within a plastic enclosure. However, I require the sensor to be positioned outside the enclosure while still being able to detect the metal through the plastic. i need a sensor effectively detect metal beyond the plastic barrier.

Please see the attachment.

I have tried inductive and capacitance proximity sensors but no success

Thank you

Please Feel free to sens your application to me at Balluff Inc, Attn: Thurston Horton 8125 Holton Drive Florence KY 41042 Testing in our Application Lab is free and will be tested the same day.
Thanks Thurston Horton Technical Service Manager 800-543-8390

 

Hi All,

I'm searching for a proximity sensor capable of detecting the compression of a spring metal, which is situated within a plastic enclosure. However, I require the sensor to be positioned outside the enclosure while still being able to detect the metal through the plastic. i need a sensor effectively detect metal beyond the plastic barrier.

Please see the attachment.

I have tried inductive and capacitance proximity sensors but no success

Thank you

Hi Majj_23

You did not specify your problem statement fully.
What is the material inside(Ferromagnetic ?),
How far is the distance travelled ?
What is the accuracy required ?
Minimum and max acceptable tolerance values ?

Assuming you are OK with few MM of tolerance, you may use any linear Encoder.
If its a harsh environment, then you may use a linear resolver.

The above are under the assumption:
1.) you have a PLC kind of intelligent device to handle such inputs.
2.) You can have a mechanical link for the sensor.

If non contact type required try using ultra sonic sensors. But they are not that much accurate .
Alternatively you may use a strain gauge as well - provided you know the character of the spring under test.