Lost Steps How does it Happen?

[High Seas]

SO how can you loose steps? I'm trying to catalog most sensable reasons here. (Sorry, using stepper motors vice servos - is just too obvious) Is it:
SOFTWARE:
Velocity set to high?
Acceleration too high?
Wrong voltage - too high/too low?
Too many z axis movements?
Hi Active vs Active Low on Step or Direction?
[More specifics added from the Balsaman; "Having the axis step pin set for active high when it should be low or low when it should be high can cause the stepper to loose one step per move."]
Step Spacing - too short/long?
Feedrate too high?
No "buffer" between pc and controller? [Is this what is meant by "drip-fed?"]
WIRING:
Wired step and direction backwards?
EMI through unshielded cables?
PARTS:
Power supply - not enough "grunt?"
Bad motor(s)?
Software stepping to fast for controller?
PC not fast enough for software?
Using Bipolar motors on Unipolar controller?
Router generating EMI?
Power supply unshielded?
MECHANICAL
System set up so the motors have to "pull against weight thats close to the max of motor?
Controller won't drive router through material at set feed rate?
Binding - threaded rod hangs up in home made bearings?
Binding - rails not parallel?
Machine crooked - rails not perpendicular?

Is the best way to know if the steps are lost -- squares are "bent?" Can this tell you which axis is loosing steps? Example: if the square slopes to higher x values as Y increases, are you loosing x steps? (On return to home after run: x not 0, but y=0.)
If these are the most obvious set of possibilities - is it trial and error to fix - or does someone have an idea of the first ones to elminate or add some other, less common ones?
Thanks heaps!
Jim

[thuffner3]

Thanks for all the possible scenerio's.

For my machine I'd be apt to believe it was PC to controller.
I have been using KCAM with little to no problems when I completely minimize every window and close up the laptop.
Just let the computer run it's course.

TurboCNC does a fine job, this possible PC to controller issue would be me and the configuration.

Let's hope the more experienced people can add some insight.

Peace
Neil