Shopbot as a shear strength measuring tool

[peter_hill]

I am wondering if I can possibly use my Shopbot to give a measure of relative shear strength of samples of wood by "driving" the x car through a small mounted test piece and monitoring the current to the x steppers as it does so. Can the control software be interrogated to determine the current drawn? If it does - how often does it sample it? Any advice as to whether this is possible would be much appreciated.

[Brady Watson]

Peter,
It would be easier to use a hydraulic press with PSI gauge than it would be to use the Bot for such a task. A standard PRT or PRS will only put out a max of 60-70 pounds of force, while a PRS Alpha with 7.2:1 gearboxes will put out about 150 pounds of force - not really the right tool for the job for a number of reasons. I am not aware of any provisions in the SB3 control software to monitor amperage. All of this is done in the stepper driver, and even if it could be accessed it would not give you reliable data. A hydraulic press & a video camera focused on the gauge will show max PSI achieved before the sample breaks...

-B

[beacon14]

You can get gauges with indicators that stay at the maximum value until reset - instead of the video camera