Arbor Press force measurement... 1

[heathenx]

i am looking for a way to measure the force it takes to "light press" fit several small parts into one another. we typically use 1/2 ton arbor presses. that should give you an idea of the smallness our our products.

basically, i want to squeeze a plastic post into a plastic hole and i want to know how much force it takes to do it. i think a "load cell" of some kind could be used but i treading on new territory. any simpler methods?

thank-you,

 

[CESSNA1]

HEATHENX: A load cell sounds good to me. Put it between the arbor and the piece and record the data. You could also do the calculation, butit is subject to error. It depends on what kind of accuracy you want. If you use a load cell make sure you do many trials to get a good representation on the data. You may also want to mount a dial indicator to measure movement then you can plot force vs. depth.

Regards
Dave

 

[plasgears]

A spring array with known constants could yield deflection info, which leads to force. Place the springs under the platten. For four springs: K (four springs) = 4K (single). Place the indicator so that it measures deflection of the springs.

 

[heathenx]

i wonder if there is a "quick and dirty" method with maybe a dial indicator and gram scale....hmmm....

 

[bobc]

on larger applications, we sometimes use a hydraulic jack with the plunger extended and a suitable pressure gauge in the fluid entry port. with all the air purged you can expect a fairly accurate gauge reading which can be then converted to "tonnage". i believe these are also commercially available.
possibly one could be rigged for a cylinder small enough for your need.

 

[Steelforbrains]

Could you monitor the pressure going to your cylinder? Apply the pressure slowly and when the pressure peaks then you are applying maximum force. If you know the bore size of your cylinder then it is a simple calculation.
Force = Pressure x Area
The area would be the cross sectional area of your bore
Area=(pi*d^2)/4

So if you have a three inch bore and you apply 200 psi to it, then the force is:
Force= (200)(3.14*3^2)/4 = 1413 lbf