Why and when using step 1/16, 32, etc ?
why using low amp or hi amp?
All step motor turn 200 1.8degre?
Which axis requide the higher nema?
The way i see that, i présumé to used the higher step revolution with the higher amp will be perform at max?

i know it is a lot of question and i présumé a lot of cnc fan will appreciate a explication

thanks

michel

Hi Michel,

Gecko explains it all far better than I can  http://www.geckodrive.com/support.html/

Tweakie.

Michel,
Like Tweakie said, read all the info on the Gecko site and more!

Let's rephrase your questions for an understanding that a system is designed to accomplish what "YOU" want to do with it!

The major components of a stepper system for any axis are:
- Motor, motor drive, components of the axis ( screw, bearings, etc), power supply. All must satisfy the
  desired operation of the cnc machine and are interelated.
- The axis must be capable of a desired acceleration, velocity, accuracy, and have the power to do the  task.

So these questions should be answered to evaluate a desired system:  

1.What will the cnc machine be used for now and in the future?
2.What will be machined?
3.What is a desired accuracy for what will be machined?
4.What min and max velocity of the axis is desired?
5.How much weight will be on the axis AND consider how efficient the axis may be?

If you answer the above you have a starting point to evaluate, if not, everything else doesn't matter!

RICH

Thks. Ok i did read Geckodrive. to answer the 5 questions.
1: wood, harwood, plastic, soft aluminium, carving, letter, machine small part
3; well, as much is possible to have a verygood finish
4: as fast is possible, i will adjust myself to it
5:z axis has a leadscrew 5\8'', and spindel 1500w
I bought a old cnc china machine 2005. 3 motors nema23, new powersupply, new mach3 USB controller,
Machine work well, but it seam to lose step on zaxis when i carve 2.5D. So my idéal is to upgrade motor and stepdriver.
Is it a good ideal?
Thks again, i really appreciate your help

Before upgrading, do the research to see if your current equipment is setup to run at its optimal condition - things like PSU voltage, drive voltage, acceleration and speed settings etc.

Might save some cash

old cnc china machine 2005

Post info on the machine. Picture, info on exactly what you bought.
Need a link to the manuals for it. Motor info and leadscrew info also required
aloong with any gear reduction, etc.

seam to lose step on zaxis when i carve 2.5D

Steppers either run just fine or skip. Skipping / looseing steps can usualy be heard and the affect of the skip can vary.
You need to tune the steppers, by trial and error, to find the max velocity
and acceleration that can used and then set the tuning,say 30 % below that value
Some % below max because you need some headroom for reliability.
Since torque decreases with stepper rpm the acceleration is obviously affected.
What you want is "power". The stepper is rated for a max amp and voltage. As the voltage goes up you will get more axis velocity, but the stepper may be of high inductance and thus the velocity becomes lmited, but the torque increases. I
wouldn't buy a stepper if it dosen't come with a motor curve and be carefull on the voltage the motor curve was create at.Of course you know all this if read the info on the Gecko site. Just remember that all this is interrelated along with
the actual hardware ie; screw , any gear reduction, just what part of the available power is being applied for axis movement only.
 
I think your problem is that the Z stepper, or maybe even the other axes don't
have the torque to accelerate the axis for the small moves being done at ( motor rpm) feedrates in the code. Of course you some control over the gcode depending on what / how a program is used to generate the gcode. Small axis moves at some feedrate ( even slow feedrates ) can cause skipping as the accelration could be almost instant in time and the axis system must be capable of providing for it.

Post the info requested and we'll see where this goes.

RICH

Ok and thks . When i tune the Z axis with mach3, i ask the stopper to move 1 inch and it move 1 inch, so it gave me a nice curve . so i figure i am ok with it, and it should move properly. Is it ok the way i did it?
Also when you say tuning 30% below, is it the value on z Axis ? or is it the value i gave in the toolpath vacarme?

Is it a good idéal if i change on motorstepper value now is 10, what will be practical action will cause if i switch at let say 32?
or should i do try each microstepr till it seam ok? 2-4-8-16-32-64-128-256-5-10-25-50-125-250?
Also a stepmotor is built 1.8degre 200step. so it can not give a nice cutting curve, for that reason we used a stopper contrôler with many range 2-4-8-16-32-etc for having more angle and more stepcutting ?  is it ok what i say?

Remember i want to do the right thing ans also understanding why i am doing this or this.

thks to you

michel

Is it a good idéal if i change on motorstepper value now is 10, what will be practical action will cause if i switch at let say 32?

Hi Michel,

As Gecko explains in their information base (as previously linked) anything over 10 is a total waste of time.

Tweakie.

Michel,

Also a stepmotor is built 1.8degre 200step. so it can not give a nice cutting curve, for that reason we used a stopper contrôler with many range 2-4-8-16-32-etc for having more angle and more stepcutting ?  is it ok what i say?

No, there is more to it than that, go back and STUDY what is on the Gecko site.

Micro stepping is just rotating the rotor a fraction of a full step and thus
how accurately it can position is limited by all the components of the axis.
Say the axis steps per unit are 20000. Then the theoretical resolution of that axis is 1/20000=0.00005" but doubt very much if you will achive that. If you want to increase the position accuracy then use gearing or a 400 step stepper
for a given screw. Remember that "all components" of the axis system must satisfy the accuracy desired.Also remember that velocity and torque will be affected.

So try jogging the axis in 0.0001" increments and see what the DRO is saying as compared to actual measurement of the move.

On the practical side.........
1.Make sure the steps per unit are correct for the longest possible axis move.
  Make sure any backlash was removed before using the axis calibration feature.
2.Now tune the axis by setting the velocity at say 10 and an accel of 1.
  - just double each value until the axis skips
  - then reduce the values by say 30% ie; if it skipped at say 100 ipm then reduce      velocity to 70 and accel to 7 and refine
  That wil get a reasonable setting for the axis and can refine with experience
  when running or testing doing different tasks.

Also when you say tuning 30% below, is it the value on z Axis ? or is it the value i gave in the toolpath vacarme?

Answer is in above

Remember i want to do the right thing ans also understanding why i am doing this or this.

Understand, but you need to learn more on your owne. Books have been written on the stepper.
  

RICH

Rich your genius...lo......now i can visualy what a stepdriver is doing, how is works.. thanks for your time and your talent to teach and simplify.  I do not know if that will fixe my little problem, but i will work on it this week and try it... So till that done, have a good weekend.


thks   Michel