Helical milling with a diagonal repeat ?

Hi

I'm not able to get to my workshop to test it, so there may be a stupid error in it, but this is a simple example of what I am trying to explain.
Also shows that using labels makes it all much more readable.

Unless you want to re-use code with different files, the sub routine is most easily located at the foot of the same file, rather than a separate file.

Once you have your head around this, you can make the sub routine do your helical mill and use the loop in the main section to move between hole positions.

;;**********************************************************************************************

(Mill diagonal series of holes at X20 Y20 offsets from corner of workpiece)

G17 G21 G40 G49 G54 G80 G90 G94

(global labels have leading underscore)
#<_Holes> = 5
#<_Counter> = 0
#<_X_offset> = 20
#<_Y_offset> = 20
#<_TopZ> = 5
#<_BottomZ> = -10
#<_Feed> = 200
#<_Z_Feed> = 20

G28
M3 S600
M7
(position over corner)
G00 X0 Y0 Z20
G00 Z#<_TopZ>

O100 WHILE[#<_Counter> LT #<_Holes>]
G91
G00 X#<_X_offset> Y#<_Y_offset>
G90
O101 CALL
#<_Counter> = [#<_Counter> + 1]
ENDWHILE

G28
M5
M9
M30
M2

;;*************************************************************************************************

O101 sub
(Local sub so uses the global parameters)
G01 Z#<_BottomZ> F#<_Z_Feed>
G00 Z#<_TopZ>
O101 endsub

hope this helps
regards

ArcEye

As a first step to enlightenment, I turned your code example(many thanks) into a file "example.ngc" and placed in my emc2/nc folder, the idea being to get a look at it in 3d as well as reading the code.
Then I loaded AXIS sim, and opened the file, but it gives me an error "unable to open file <101>.
I have an idea that the call file needs to be loaded separately, also into the nc folder, but I'm not sure if this is so, or the details of how to do it.
Can you put me right on this ?
Many thanks
John

Thanks John. Once I'd got the file named correctly it worked fine.

Thanks ArcEye. I now have another bit of coding I can start to use.

And thanks to Andy for getting the ball rolling.

Regards,
John

Hi all,

I've just tried out the sub routine for a spiral (posted by Andy) and it seems to generate a perfect spiral for the most part, but the first 1/4 of a circle pass and the last passes at the bottom of the hole are slightly elliptical. Do you have any idea why and how to correct this? My G-code arc fu is weak!

Thanks,
Ed

Interesting - it's certainly doing something odd, there's a definite difference between the radius of the spiral and the radius of the start/stop points. It shows it in axis too when run, I set up the sub routine file then called it using the command entry in axis, this gave me a little test spiral but definitely not quite what I expected!

Thanks,
Ed

I don't suppose you've got a lathe, Andy? I could stop all these circular shenanegans if I could find someone who'd be willing to run a few passes on a little alu part!

Well, I was just considering purchasing this: www.ebay.co.uk/itm/190756617817 to do what amounts to about 10 seconds work for a CNC lathe.

I have a little threaded part with an internal bore, this needs to be enlarged to be a snug fit onto a tube. If you'd like a small job of this ilk, name a price and I'm sure we can work something out! Thanks

Ed