Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: bryson on November 20, 2009, 03:29:15 PM

Title: creating small circles
Post by: bryson on November 20, 2009, 03:29:15 PM
Hi all,

I wanted to know what the smallest circle mach3 can make. 

I used the command below and it made a circle of about 2" in diameter.

G02 I0 J.03

I need the circle to be .060" in diameter(.030" Radius).

my default units are inches.

Is there any setting that i can change to make the circle as small as i would like?

Thanks,

-Bryson
Title: Re: creating small circles
Post by: HimyKabibble on November 20, 2009, 03:49:11 PM
In Config->GeneralConfig, do you have I,J set to incremental?

Regards,
Ray L.
Title: Re: creating small circles
Post by: rrc1962 on November 20, 2009, 04:33:06 PM
I have no idea how to hand code that circle, but my CAM produces this for a .060 circle with no tool offset.

G1 X-0.0300 Y0.0000 Z0.0000 F120.0
G2 X0.0000 Y0.0300 I0.0300 J0.0000
G2 X0.0300 Y0.0000 I0.0000 J-0.0300
G2 X0.0000 Y-0.0300 I-0.0300 J-0.0000
G2 X-0.0300 Y0.0000 I-0.0000 J0.0300
Title: Re: creating small circles
Post by: bryson on November 20, 2009, 05:16:41 PM
great! that worked out fine.

now i have a new delemma.

I have the spindle output hooked up to a pnematic air gun that dispenses glue.  The glue is going to form the .060" diameter circle.  the problem is the blasted spindle dwell.  When the M3 is called out, the glue comes out for .5 seconds and then does the circle and then comes out another .5 seconds after the circle is done.

Is there any way to make the glue start and stop exactly when i want it to?

thanks,

Bryson
Title: Re: creating small circles
Post by: RICH on November 20, 2009, 05:19:36 PM
"I wanted to know what the smallest circle mach3 can make."

I think it depends on what your machine can do so you can tell that it is a circle.

RICH
Title: Re: creating small circles
Post by: RICH on November 20, 2009, 05:27:52 PM
Maybe you need to review how you are doing the glue dispensing as a syringe pump comes to mind.
RICH
Title: Re: creating small circles
Post by: bryson on November 20, 2009, 05:37:13 PM
We have a syringe hooked up to a nuematic air machine and an air compressor.  The Syringe is fastened to the XY machine.

On a standard circle,  the code is like this

Y0 X0
M3 (glue turns on for .5 sec and piles glue up)
G02 I0 J-.03 F100 (glue dispenses in a circle)
M5 (glue is on for .5 sec, glue piles up and then glue shuts off)
Y1 (moves 1 inch to next circle)
M00


Is there anyway to make the glue start the instant the circle is being formed and stop the exact instant the circle is finished?
Title: Re: creating small circles
Post by: Hood on November 20, 2009, 07:12:50 PM
There is an M10 and M11 function in Mach which I believe can be used and has very little delay. I dont know how it works or how to use it but if you do a search you should find some info. If I recall the guy that seems to have got it working just said to PM him for info rather than post it on the forum, so you might have to do that.
Hood
Title: Re: creating small circles
Post by: rrc1962 on November 20, 2009, 11:54:47 PM
If I were after a more exact dispensing method, I'd probably use a screw driven syringe rather than air pressure.  You'd have far more control with a screw driven dispenser.  You could drive a screw syringe with a rotary axis.
Title: Re: creating small circles
Post by: Tweakie.CNC on November 21, 2009, 04:52:32 AM
Quote
I have the spindle output hooked up to a pneumatic air gun that dispenses glue.  The glue is going to form the .060" diameter circle.  the problem is the blasted spindle dwell.  When the M3 is called out, the glue comes out for .5 seconds and then does the circle and then comes out another .5 seconds after the circle is done.

You could reduce the delay from your 500mS to 210mS quite simply by setting mist coolant (M7) to the same output# as your spindle (under ports & pins/spindle setup) and setting the delay as zero then with a GCode editor modify your code to block replace the M3 command with M7.
I wonder, would this be a large enough saving in execution time ?.

Tweakie.
Title: Re: creating small circles
Post by: bryson on November 23, 2009, 02:26:59 PM
thanks for the M7 directions.  I did help a bit with the delay.  Im still looking for no delay after axis movement..

Anybody else have any suggestions?
Title: Re: creating small circles
Post by: stirling on November 23, 2009, 03:12:21 PM
try replacing doSpinCW() with activateSignal(OUTPUT1) in M3 and doSpinStop() with deactivateSignal(OUTPUT1) in M5. This got both down to around 0.1 secs for me. Then if you like make M1000.m1s and M1001.m1s (or whatever free numbers you like better) with activateSignal(OUTPUT3) and deactivateSignal(OUTPUT3). Obviously you'll need to change your pin to Output3 in ports n pins and call M1000 and M1001 instead of M3 and M5. This got the delays down to around 0.05 secs on my system. Though why different M numbers and output 3 should be faster than M3/M5 and output 1 (especially on the same pin!!!) I don't know.

Hope this helps

Ian