Will modifying a Load Cell affect its accuracy?

Thread Starter

UtahSlacker

Joined Jan 13, 2019
2
Load-Cell.jpg

Hello.

I'd like to modify a crane scale as attached to suit my purpose.
Will cutting the ends off and drilling holes in the load cell affect its accuracy?

Hopefully I added the photo correctly...

Thanks,

JJ
 

Alec_t

Joined Sep 17, 2013
10,597
Won't changing the geometry of the cell affect the gauge constant? Doubtless re-calibration would overcome that.
If the cell's resistive element is in a zig-zag form, chopping off the ends may remove its connections.
 

Reloadron

Joined Jan 15, 2015
4,701
Will cutting the ends off and drilling holes in the load cell affect its accuracy?
I am going to vote a strong yes, it will have a strong effect on the load cell accuracy. Here is why I am thinking yes. My guess is that under the white blob is a strain gauge. I can show you numerous examples. That strain gauge is designed to work with the surface it is mounted to when a load is applied in a certain manner the pictured mounting is stressed. That stress causes the resistance of the strain gauge to change ever so slightly. The gauge itself is part of a balanced bridge so as strain or force be it tension or compression the bridge becomes unbalanced creating a small voltage change. Everything depends or hinges on that frame the strain gauge is mounted on. Altering the mounting frame in any way will sort of upset the apple cart. The strain gauge in this case looks to be mounted on a beam, the placement of the strain gauge (white blob) is critical to how much strain the beam will exhibit when a force is applied to a given point on the beam. So if we alter the beam making it shorter or even longer the resulting output will change.

That would be my guess and I would not alter the beam in any way. Doing so would require a complete new calibration curve. The beam mentions 300 Kg so I assume that is the full scale load the beam and subsequent system is designed around. I have no clue what the numbers would do if you alter the beam.

Load cells come in many configurations so you may do better trying to find another load cell which will have a better fit in your intended application.

Just My Take...
Ron
 

Thread Starter

UtahSlacker

Joined Jan 13, 2019
2
Thanks for the input everyone!

I'm wanting to use an all the existing internals (load cell, pcb, digital display, battery, wiring etc.) from a crane scale, as that would be the quickest / cheapest way to go to try an idea - So no ability to recalibrate / program anything in any way.

It would be mounted in tension from the four holes.

My hunch is the same as the consensus so far.

There's one way to find out for sure... : )

JJ
 

LesJones

Joined Jan 8, 2017
2,417
Using a two hole fixing at each end could apply a bending force instead of just a tension force with the original single hole each end. That is in addition to the reasons already mentioned.

Les.
 
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