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Author Topic: New to CNC and built my own CNC but now come the questions  (Read 1245 times)

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Re: New to CNC and built my own CNC but now come the questions
« Reply #20 on: April 07, 2019, 02:39:31 AM »
Hi,
are your steppers direct coupled to the ballscrews?
What microstepping regime have you got your drivers set to?

Craig
My wife left with my best friend...
     and I miss him!
Re: New to CNC and built my own CNC but now come the questions
« Reply #21 on: April 07, 2019, 02:58:43 AM »
I have motors connected directly to Ball screws. I have settings set sw 1 ON sw2 ON sw3 OFF, sw4 I left off and then I thought I needed to set sw 5 6 7 8 25600 not sure where I read something about that so OFF OFF OFF ON for SW5 thru 8.
Re: New to CNC and built my own CNC but now come the questions
« Reply #22 on: April 07, 2019, 03:15:31 AM »
Hi,

Quote
I have settings set sw 1 ON sw2 ON sw3 OFF, sw4 I left off and then I thought I needed to set sw 5 6 7 8 25600 not sure where I read something about that so OFF OFF OFF ON for SW5 thru 8.

That does not mean that much to me, these are your stepper drivers, you have them in front of you. You have to use the
driver instructions to determine what that means.

If your microstepping regime is 25600 steps/rev its unrealistic.

You need to set the switches for 8 microsteps per full step or 1600 steps/rev. Note that 4, 8, 16 or even 32 microsteps
per fullstep would be adequate. Adjust the following calculation to suit if you choose other than 8 microsteps.

I assume because you have metric ballscrews that your native units are mm?

Then you steps per unit, which you put in the motor tuning page would be:

1600 (steps/rev)/5 (mm/rev)=320 steps per unit

I would set, as a preliminary estimate, a max velocity of 500 rpm or 500 X 5 =2500 mm/min
I would set, as a preliminary estimate, a max acceleration of 500 mm/sec2

Craig
My wife left with my best friend...
     and I miss him!
Re: New to CNC and built my own CNC but now come the questions
« Reply #23 on: April 07, 2019, 03:27:50 AM »
Well Craig you have giving me a starting place and just think I thought I had a little grasp on this area and now realizing I need bunches of help. I will go in and check and I am sure I used inches.

Thanks again for coming through for me, Tim
Re: New to CNC and built my own CNC but now come the questions
« Reply #24 on: April 07, 2019, 04:12:18 AM »
Hi,
if you are using metric ballscrews then why use inches?

If the calculation is done in inches:

1600 (steps/rev) / (5/25.4)= 8128 steps per unit (in inches)

Craig
My wife left with my best friend...
     and I miss him!
Re: New to CNC and built my own CNC but now come the questions
« Reply #25 on: April 07, 2019, 02:00:04 PM »
 Well I am obviously a bear of small brain, now that you put it that way makes very good sense :) ! I am heading out to do the settings in few minutes and will post a update, mucho thanks
Tim
Re: New to CNC and built my own CNC but now come the questions
« Reply #26 on: April 07, 2019, 06:47:16 PM »
 Howdy Craig, after re reading many times this bear of small brain understood, I always get mixed up when taking about Stepper motor which is used many times to say stepper drivers. Anyway I made the adjustments and the machine came to life. I am sure I will be doing some fine tuning but its works and I owe you a BIG Thanks!! attached is a picture of my SAW 1st test cut

Thanks sooooo much!

Tim
Re: New to CNC and built my own CNC but now come the questions
« Reply #27 on: April 07, 2019, 06:57:04 PM »
Hi,
kool. CNC is one big learning curve.

Craig
My wife left with my best friend...
     and I miss him!

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Re: New to CNC and built my own CNC but now come the questions
« Reply #28 on: April 07, 2019, 07:37:27 PM »
Very nice construction, congratulations on a job well done.
However I do see one problem. There are 3 power supplies with fans in the bottom area. I hope you have a plan for filtering the sawdust out of their cooling air.

Offline reuelt

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Re: New to CNC and built my own CNC but now come the questions
« Reply #29 on: April 07, 2019, 09:46:49 PM »
Congratulations for nice construction.
Your ESS, motors and drivers etc are well PREPARED for a future much larger table possibly with wide movable gantry so that heavy 8'x4' or 10'x5' plywood and long hardwood (for huge sign) could remain stationary.
For a large table, consider tensioned "bicycle chain" type design for the x-axis (the longest axis) instead of a ball-screw and BACKLASH will be then mechanically zero and you can even move the gantry easily by just pushing when the motor is off instead of having to slowly turn/crank the ballscrew.



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