PDA

View Full Version : G12/13 making large circles rather than helix



forhire
02-25-2014, 10:53 PM
Hi Scott,

My helix is appearing as a large circle rather than a small corkscrew that I'd expect. I've looked at G130.PRG and I'm confused. Either I'm using the wrong one or I need to re-write the one I'm using. This is a snippit of the code I'm playing with.



G0X-0.3915Y0.2498
G1Z0.025F1.
G0R0.015I-0.4065J0.25A147.4389Z0.025
G13A504.Z-0.0625F2.
G3X-0.4215I-0.4065J0.25K-0.0625
X-0.3915I-0.4065J0.25K-0.0625


The control is a Bridgeport DX-32 and this is the syntax from the manual.


G0(G1)R__I__J__A__Z__ (F__) ;Move to Helix Start Point
G12(G13)A__Z__F__ ;Do Helix

G1 is the G-Code for XYZ Linear Interpolation (Feed);
G12 is the G-Code for Helical Interpolation in a Clockwise Direction (CW);
G13 is the G-Code for Helical Interpolation in a CounterClockwise Direction (CCW);
A__ is Polar Angular Motion defined in terms of the total number of degrees of
helical travel (for G12 & G13 only). This is an “unsigned” incremental value;
Z__ is the absolute depth of travel;
F__ is the Feedrate;
R__ is the Arc Radius; and
I__, J__ are the X & Y distances (respectively).


Thanks in advance.

225714

MetLHead
02-27-2014, 06:08 PM
The G12, G13 that comes with NCPlot is a simple circle macro which is based on another control. These macros would need to be updated to simulate your helix cycle.

Thanks,
Scott

forhire
02-27-2014, 09:01 PM
The G12, G13 that comes with NCPlot is a simple circle macro which is based on another control. These macros would need to be updated to simulate your helix cycle.

Understood. I've looked at the macros and read in the help but I'm stumped as to read the correct values. I image the macro would write a series of circles.

Here's a simpler threadmill example with the G13 replaced with G3.


N110 G0 Z-0.5333
N120 G1 R0.040039 I0. J0. A0. F5.0
N130 G13 A360. Z-0.477781 F5.0
N140 G1 X0.0000 Y0.0000


And with with the G13 replaced with G3... this renders correctly. ;)


N110 G0 Z-0.5333
N120 G1 X-0.040039 Y0. F5.0
N130 G3 X-0.040039 Y0. I0. J0. Z-0.477781
N140 G1 X0.0000 Y0.0000


I've played around with this a bit and it would appear that I'd need to evaluate both the the G13 (N130) line and the prior line G1 (N120) that sets up the start point. If I can figure out how to get the R, I, J, A values from the first line and the A, Z values from the second it would be fairly easy to make the macro. I'd also need to know the current Z (N110) I suppose. Obviously this is an overly simplified example as I'm not taking into account starting at any angle other than zero.

Can you point me in the direction to get started?