[Dan.antes]

I need someone to clue me in. I have a Paoloni wood shaper that the spindle up and down universal joint broke. I think I would like to replace it with a small servo or stepper that would allow me to postion the spindle height digitally. Is there someone that can recommend a small motor that I can attach to the existing 3/8" shaft that spins the pinion gear that turns the lead screw. Also I guess I would need a PLC and a readout. What would be the considerations in this modification? How hard would a PLC be to program to manage this application? Please make product suggestions and any other information that may be pertinent. Thanks

[Al_The_Man]

Assuming it does not have a motor at present, then you would need to to a couple of test to find out the torque needed to position the motor, If you are just moving to a fixed position, you do not need to factor in accel/decel rates so measuring the break away torque should put you in the ball park.
The method of control would be decided by what level of proficiency you may have as to programming different methods, it can be done with a stand alone system such as PLC as they have stepper and servo option output cards, you would need a small 2 line display/keypad for operator entry, Maple Systems make a variety of these for most makes of PLC's.
Al.

[Dan.antes]

Al,


Would a torque wrench attached to the worm gear shaft give me a reading of the torque it takes to turn the shaft? I am thinking the torque is fairly low since the worm gear to pinion to lead screw set up seems to be about 10:1 reduction already. With a PLC can I use a dial indicator to measure actual spindle travel and then program the PLC to match that or do I need to know the actual gearing ratio of the worm,pinion,lead screw? Can you suggest a few web links to look at parts? Here are a couple of pictures of the shaft end of the worm gear and the lead screw. Sorry pictures are rotated counter clockwise. Thanks

[Al_The_Man]

You can make an informed reading using a sensitive torque wrench.
If you do not need to position by numeric command, you can use a simple analogue pot or digital step direction module.
A servo drive will give you encoder feedback where you can put a digital readout on if this is precise enough.
Another option is to fit a brake so whenever the spindle is in position the brake is engaged and the servo turned off.
Some of the cheapest ways for stand alone applications like this is Automation Direct,
http://www.automationdirect.com/adc/...Motion_Control , they supply PLC's, displays, servo's etc.
A lot depends on how much sophistication is required for the type of control you are looking for.
Al.