eShapeoko recomented microsteps and steps/mm for accuracy

Talk about all things CNC
Post Reply
Georgei
Posts: 148
Joined: Mon Dec 22, 2014 11:22 pm
Location: UK

eShapeoko recomented microsteps and steps/mm for accuracy

Post by Georgei » Sun Jan 25, 2015 2:10 pm

Hi everyone,

My motors are Nema17 (high torque) and they have 1.8 degrees step (200 steps/ rev).
The controller I am using can go up to 1/16th micro-stepping.
The belt in x,y is MXL with a pitch of 0.08" or 2.032mm and 18teeth pulleys.
In z is a TR8x2 lead screw with 2mm/rev pitch.

Can anyone suggest what micro-stepping and steps/unit (in my case steps/mm) will give the best performance for high accuracy (inlays).

Any suggestion are welcome.

George

akhlut
Posts: 304
Joined: Wed Mar 27, 2013 1:16 am

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by akhlut » Sun Jan 25, 2015 2:37 pm

If your steppers are rated at 5%, then 1/8 step. Anything above this is phantom resolution.

43.788 for X and Y

800 for Z

http://nathan7.eu/stuff/RepRapCalculato ... rStuffSPMB

Georgei
Posts: 148
Joined: Mon Dec 22, 2014 11:22 pm
Location: UK

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by Georgei » Sun Jan 25, 2015 3:43 pm

akhlut wrote:If your steppers are rated at 5%
I suppose the 5% is the error of the motors. Is this percent per revolution or per 1.8 degrees step?

George

akhlut
Posts: 304
Joined: Wed Mar 27, 2013 1:16 am

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by akhlut » Sun Jan 25, 2015 6:22 pm

A step motor is a mechanical device that is manufactured to a certain tolerance. Typically a standard motor has a tolerance of +/- 5% non accumulative error regarding the location of any given step. This means that any step on a typical 200 step per revolution motor will be within a 0.18-degree error range. Stated otherwise, the motor can accurately resolve 2000 radial locations.

Source

Georgei
Posts: 148
Joined: Mon Dec 22, 2014 11:22 pm
Location: UK

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by Georgei » Sun Jan 25, 2015 9:04 pm

That is exactly the settings I have right now.

What will be the recommended max values for velocity and acceleration for these values?

George

Gadgetman!
Posts: 1061
Joined: Sun Aug 25, 2013 12:44 pm
Location: Norway
Contact:

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by Gadgetman! » Sun Jan 25, 2015 9:22 pm

That depends entirely on the stiffness of your machine and the components you've used...

Can you list what you have, possibly with a picture if you've done something not entirely stock, and possibly what kind of accuracy you're getting now?
(with feeds and speeds, material, endmill and all that)
Weird guy...
Shapeoko 2014F: 1000mm X/Y, 300W Quiet Cut spindle, Arduino Uno/G-shield and GRBL 0.9i
15x30 drag chains, custom spindle mount, 9mm belts, 8mm endplates, 6mm motor plates.

Georgei
Posts: 148
Joined: Mon Dec 22, 2014 11:22 pm
Location: UK

Re: eShapeoko recomented microsteps and steps/mm for accurac

Post by Georgei » Sun Jan 25, 2015 9:38 pm

The machine will be an eShapeoko 500x500 with double rail on the x axis.
Obviously I haven't got the machine yet but I am setting up all the electronics (programs settings motors etc).

The machine will be used mostly for engraving and for inlays (luthiers inlays) in hard wood.

I am not looking for the feed rates for cutting but for the maximum safe speed for rapids (if the term is correct meaning moving fast without cutting).

George

Post Reply