Messages

11

General Mach Discussion / Re: Lathe control panel

« on: November 27, 2008, 01:54:04 PM »

Looks good!
what MPG did you use? I think I've read somewhere that 500 cpr are recommended if your trying to achieve manual control through the MPG.  That'll be another project - to get the feel of a manual handwheel....

12

General Mach Discussion / Lathe control panel

« on: November 27, 2008, 08:25:05 AM »

Greetings all,

I've just about finished the retrofit of a Denford ORAC to MACH3 control and updated electronics. I'm trying to find some inspiration for a layout of a 'manual' control panel, similar to the Harrison Alph330. I've spent a few days trawling these forums in the hope of finding a photo or two, but no luck. And the annoying thing is, I'm sure I've come across this information before, thinking 'I'll remember where I found that' Doh!

Does anyone have a link to such a resource?

Many thanks,
Frogeye

13

General Mach Discussion / Re: Rapids change spindle speed

« on: November 09, 2008, 12:57:42 PM »

Hi Roy,

I was talking to a guy at Newton Tessla here in the UK when making the purchasing decision for the Mitsubishi inverter..... He had experience of the brown & pestall and said that it didn't have a linear output and that it was all a bit of a fudge.  So it seems probable that you have found the limits of this VFD.  In comparison, I find that the speed on my setup is about +- 20 rpm throughout the speed range, as measured by a mechanical tacho.
Paul

14

General Mach Discussion / Re: Rapids change spindle speed

« on: November 01, 2008, 02:23:39 PM »

Thanks for your help Hood, it pointed me in the right direction 

Update......
Spent the afternoon trying to nail this.  Was able to try a different turn profile (xml file) and this did not exhibit the problem. After that, it was a case of comparing the two.  The parameter that was causing the problem (in this case) was found in Ports & Pins, Motor Outputs. Spindle dir lowactive was on and turning it off cured the problem. Just needed to tweak the motor tuning to get the right voltage out of the C11G.

Though why this caused the problem in the first place, I would love to know!

Cheers,
Paul

15

General Mach Discussion / Re: Rapids change spindle speed

« on: November 01, 2008, 09:46:19 AM »

OK, a bit more information

Tried increasing pule width for spindle to 5mS. Needed to tweak the pot on the C11G up a tad to get full output, but other than that, no improvement.
I have noticed that this phenomenon is very controlled.
Spindle running at 800 rpm,  output to VFD from breakout board 4.00v, jog Z at 10% and speed and output from BB increase by 10%. This is so for other jog values up the maximum spindle speed of 2000 rpm. 

I've just tried this on the x axis, and the results are exactly the same. Does anyone else see this 'problem'... Is it the way MACH is designed to work??

Any suggestions gratefully received..as always

16

General Mach Discussion / Re: Rapids change spindle speed

« on: November 01, 2008, 05:33:01 AM »

Hi Hood,
I'm using MACH ver 3.041 and spindle control is via a C11G breakout board and Mitsubishi FR-D720S inverter.  If memory serves, the pulse width for the spindle is currently 1, so I'll try that first.
Many thanks,
Paul

17

General Mach Discussion / Rapids change spindle speed

« on: October 31, 2008, 07:06:40 PM »

Hi All,
I've recently retrofitted an ORAC lathe with new electronics, running it with MACH3. I'm pretty much there - turned a great 90deg radius! but....
I've noticed that with the spindle running, rapid jogging the Z axis causes the spindle to speed up. It slows to its original speed when you stop jogging. Now while not a major problem, this also shows when thread cutting, which may be the reason I've failed to cut anything like a clean thread.
I'm sure it's a configuration problem, though I've not found it. Turning CV on/off does not have an effect.
Any pointers gratefully received!
Paul

18

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: October 07, 2008, 01:36:30 PM »

Hello all,
My name is Paul and I'm fairly new to CNC. My current project is a Denford ORAC retrofit. So far I have fitted all the new hardware (C11G breakout board, Mitsubishi D720S inverter and MSD980 stepper drives from Motion control products.  The other night I managed to calibrate the X and Z axis  a real sense of achievement!! Now all that's left is to sort out the spindle control and find the reason for pesky, false, limit switch errors.