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LDmicro Forum - CNC router (question for David R)

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CNC router (question for David R) (by Max)
Hi David,

In the following thread
http://www.cq.cx/ladder-forum.pl?action=viewthread&parent=427
you said that you build a controller using a 877 and Ldmicro...

What is your maximum step frequency ?

Is it possible for your to share you schematics and code ?

If anyone else have experience with that kind of stuff, please share it here

Thanks
Fri Dec 17 2010, 12:40:48
(no subject) (by David R)
Hi Max I am not sure what the frequency is, but my machine runs at 1000mm/min using 5mm pitch ball screw and halve stepping on the motor ( making 400 steps per rotation 16mm/sec 3.3 rot/sec *400 =1.333Khz????????????.

I don't have any schematics for the controller but I can sketch something up for you, The only thing important about the controller is S/R latch used on the step input signal to ensure the pic does not miss A pulse.

I used A pic but next time I would use A atmega32
and build A individual controller for each axis.

I will post my code and more info in A couple of days.

Regards
David.
Fri Dec 17 2010, 23:33:06
(no subject) (by Max)
Thank you very much for your reply, I'm impatient to see you work !
Sat Dec 18 2010, 09:32:29
(no subject) (by David R)
HI Max here is the code for the mill.
I will get the circuit to you tomorrow
David
Thu Dec 23 2010, 03:52:33, download attachment mill_controller.ld
(no subject) (by Max)
Hi David,
Don't forget to post your schematics...

Thanks
Sat Jan 22 2011, 10:36:43
(no subject) (by David R)
Sorry Max I don't have any schematics, I need to draw then as the circuit is on prototype board.
I will draw A simple schematic on paper and scan and post for you to day.
Sat Jan 22 2011, 14:38:24
(no subject) (by David R)
Hi Max here is A schematic it is not the mill but it is close,
if you look at the steeper motor driver and the SR latch inputs

Regards
David.
Tue Jan 25 2011, 03:50:01, download attachment stepper.JPG
(no subject) (by Max)
Thanks David for sharing this

I wondering why do you want to use an Atmega 32 rather than a PIC and build 3 separate controller... is it to be able to speed up your scantime, from .2 ms to .1 ms ?

By the way, what is the torque of your stepper and what kind of stuff are you milling ?

Thanks
Sat Jan 29 2011, 12:53:19
(no subject) (by David R)
Hi Max yes the reason is scan time, just because you set .2ms scan time if the program is big the processor can't scan it that quick!
The interesting thing is the stepper motor is a bit like a speaker, it has a note and when you add or remove program it is quite surprising how much that note changes.

The stepper motors are keling Technology Kl32H276-30-8B
the supply is 12 volts from the PC power supply (I am weighting for the backlash from everybody regarding that) but it has been running for about 2 years with no problem!.

I mill PCB's and Al or steel The limiting factor is the torque of the High Speed Spindle, it is designed to run 24000 rpm,
But by using A good quality VSD I run as low as 500 rpm wile still maintaining good cutting torque, but in steel it has trouble turning much more than 1/4" cutter.
Mon Jan 31 2011, 01:56:35
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