[1Jumper10]

I tried searching but didn't find much. Has anyone incorporated some type of linear position feedback sensing in their router? If so, how did you do it? I used stepper motors for my router and was kicking around adding some type of positional feedback system. Ive had a couple times where I've lost steps on some operations mostly due to my learning curve and inexperience with machining. But it made me think about positional feedback and how its a better mousetrap. Anybody?

[alan_3301]

Not worth it for steppers. Work within the limits of the machine, is what everyone does.
The linear encoder can't really be used to increase the resolution of the machine, because of the stepper's fixed resolution.
It could be used for mapping your screw or drive system to be more accurate, but that will do nothing for stalling or losing steps.
At best it could be linked in the control to stop the system if the stepper loses position, to attempt to save the workpiece

[1Jumper10]

I was more interested in the ingenuity of others than in solving a problem i dont really have. Somewhere on the zone a while back, I stumbled across a post where the poster was describing how he had used a hall effect sensor to detect the passing of the teeth on his rack and pinion drive and using that as positional feedback. I thought that was pretty smart. It got me thinking about other methods of positional feedback. Not to increase resolution but to verify position. Im pretty sure there are optical scales that could be taped along an axis and then read by a sensor as the axis moved over it. Just wondering if its been done and how it was done.

[louieatienza]

In the linear and rotary motion section one ingenious individual was able to hack DRO scales to work as encoders for his servo system, and by the looks of the videos it seemed to work well. He wasn't really pushing the federate however so I don't know how reliable it may be at speed.

[UA_Iron]

Certain off the shelf drive controllers can servo a stepper motor and use an external linear encoder as the position commutation device (in addition to the rotary encoder closing the velocity loop located on the stepper).

In quantities you might be looking at 300-400 an axis for the stepper controller - add in the high cost of the linear encoder and it makes it not as feasible.