Sensor quick mounting need help with ideas

[dejan95]

Hello everyone!

I'm having some trouble coming up with a good idea on how to make a quick mounting for a sensor. For every part that is beeing checked the sensor is mounted on screw head (DIN912). On one side of the screw head there is just few mm space (just for better understanding).
This is the senzor: (SYTRAN 3023A2 S/N 9847)

And this is the current design:

Current design is made with a magnet and this mounting part. The problem is that is not fixed hard enough and it rocks to much during testing.

Does anybody has any idea how could i make a fast mounting of the sensor on the screw head? I thought about a more powerful magnet but I'm not to keen on this idea. Maybe some sort of a
clamping sleeve?

Thank you guys in advance!

 

[rb1957]

glue ?

another day in paradise, or is paradise one day closer ?

 

[BrianE22]

Could the rocking be caused by non flat surfaces? Try a 3 point mount with the 3 legs spread far apart. Legs would have to have enough cross sectional area to pass the magnetic flux.

 

[EdStainless]

Better magnet and shorter base.
I have built ones 1" diam x 0.5" tall that required tools to remove the grip was so strong.
The magnet should not contact the surface, there should be pole pieces (either inner and outer or left and right) made of steel that can be ground flat for good contact.


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P.E. Metallurgy, consulting work welcomed

 

[stick1]

Proper mounting maximizes the undisturbed frequency range of the accelerometer response. When we need to mount an accelerometer to a screw or bolt, we replace the fastener with a hex head bolt that has had the top face of the bolt head machined so that it is flat (ideal = 0.0003 inch TIR) and has a good surface finish (ideal = 63 micro-inch). Then the accelerometer is bonded to the hex head bolt using Loctite 454 or Permabond 910 (both available from McMaster Carr). Another option is using double sided adhesive tape between the accelerometer and the bolt head. This is all provided that the bolt head is large enough to match up to the mounting surface area of the accelerometer. You don't want the accelerometer mounting surface overhanging and unsupported.

 

[IRstuff]

If you need strong magnets, ripping apart some rotating harddrives and grabbing the disk head actuator magnets would work REALLY well.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[BrianE22]

Is the screw on an existing product and not easy to change out? If not, then maybe get some special screws made with large, flat heads.

Beeswax used to be common for mounting accelerometers. I don't know if it still is.

 

[dejan95]

Thank you everyone for your help.

I now talked with our programmer to realise what the problem with current design was. As I said the problem was too much shaking of the sensor. When we used a clamp (that is seen in the above picture) the shaking was OK but there was conductivity between parts. So one part should probably be made out of plastic?

I'm attaching some more pictures for better understanding.

I thought about making one part plastic and otherwise making the same design. Does anybody have any better ideas?

 

[kjoiner]

What if you machined or 3D printed a sleeve similar to what you show above and then epoxy neodymium magnets into place. It looks like you already have some magnets in use. Also, is there some way to make use of the slot to mechanically fasten the sensor in place?

Kyle

 

[BrianE22]

So it's an electrical problem? I'd think connecting the product body to the accelerometer body with a low resistance wire would be the best way to handle that electrical noise. You might want to start a new thread in the electrical forums.

 

[EdStainless]

Do the magnets alternate polarity? Are they set into something non-magnetic? Is there a steel (magnetic) backing? Are the faces of the magnets flat within <0.001"? Has the bolt that you are mounting to had the top surface ground flat?

I don't like exposed magnet mounts because they are fragile and I can generate more force by using pole pieces.
There is no reason for this mount to more than 0.5" thick.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Strong]

The "sensor" is a triaxial accelerometer. I believe the name listed in OP is incorrect:

https://www.dytran.com/Model-3023A2-Triaxial-Accelerometer-P2392/

Mounting considerations:

https://www.dytran.com/images/artic...design_Proposal_Signed_8_19_16_ApexGlobal.pdf

Mounting Bases:

https://www.dytran.com/Adhesive/

https://www.dytran.com/Magnetic/

https://www.dytran.com/Isolated/

The mounting must be controlled for axis orientation and for frequency response. The magnet looks unusual (nonstandard or OEM stock) and was probably designed for a specific mounting situation, and not the way you are using it in the photos.

Typical mounting methods include using a metal disk base with stud attachment to accelerometer and with base attached to a flat surface with various adhesives. I have used petrowax, hot-melt glue sticks, 2-part epoxy, epoxy putty, dental cement, and super glue.

Avoid using a plastic base unless measuring only low frequencies and temperature is low.

What is your application such as motor/machine on manufacturing test stand, special R&D testing, or vibration surveys in a plant environment?

Walt