Table-top tensile tester 4

[14years]

Hello,

I'm trying to find or build a small table-top tensile tester. Neither of the grips can be stationary-- both must move outward from a center point, i.e. driven by the same screw. It must also have load measurement. The specifications beyond this are not important, as it will serve as a demo device for our product and the specimen will be designed to match. Any ideas as to where I should start? Thanks!

David

 

[Sparweb]

You could try using a couple of round bars as slides for each grip, and a turnbuckle to push them apart...
What kind of ideas do you have?

Steven Fahey, CET

 

[Barry1961]

A variation on the turnbuckle would be to couple a left hand and right hand threaded rod then spin the rod. I have done this often with acme screws to provide adjustment for fixtures. You could use a load cell to measure force. Oversize the drive motor to overcome the static friction of the two nuts.

You could also do the above with ball screws and measure the force with the drive motor torque if using a servo.

You could also use a high reduction gear motor and a chain or polychain with one gripper attached to either side on the belt, top and return.

You could use a double rack and pinion.

You could use a double crank.

How much force, stroke, accuracy and money?

Barry1961

 

[geoffthehammer]

There is a bench top tensile tester called a Hounsfield Tensometer now manufactured by Monsanto. Try a web search on Hounsfield-Tensometer

 

[geoffthehammer]

Also do a search on Monsanto Tensometer

 

[14years]

Thanks for the replies.

Budget is $3,000. Accuracy is not important. Force is probably no more than 5 lbs.

Are there any turnbuckles designed to be motor-driven, i.e. outside of the Home Depot variety? This sounds like the simplest solution, but after searching I'm not coming up with any good options.

The double rack might also be promising. I'll start looking into that. I'm not sure we'll have money left over for ballscrews after the motor and controller-- if we can even afford those. Any speficic brand name or product recommendations? Thanks again.

 

[limct]

Any reason why can't you have one grip stationary? this will make the equipment less complicated. The budget of $3,000 could be too tight for a double movable grips.

Best regards,
ct

 

[14years]

It does kind of butt heads with our budget (at this point I don't even know if this is doable at all), but it is a requirement-- we work with digital imaging, and need to track a viewing area centered about one point on the surface of the tensile specimen.

 

[ARenko]

Here are a couple, but with only one grip moving. Why do you need both grips moving? Maybe they can make one with both grips moving. There's lots of others like these used in the geomembrane industry for field testing.

http://www.demtech.com/modules.php?name=Products&func=protester

http://www.columbineint.com/prod_disp.php?id=55

 

[ARenko]

Sorry, just noticed your answer on the two grips moving.