Here is a partial solution. It is an input filter that converts this input:
Code:
(dragknife test)
G21
G0 X10 Y10
F10
G91.1
G1 X10 Y -10
G1 X-10 Y-10
G1 X-10 Y10
G1 X10 Y10
G3 X10 Y -10 J-10
G3 X-10 Y-10 R10
G90.1
G3 X-10 Y10 I-10 J0
G2 X10 Y10 R20
M2
To this output
Which almost, but not quite, does what is needed.
The problem I am seeing is that whilst he angles of the starts and ends of arcs are correct, the tool won't necessarily turn the right direction to cut properly.
But I am going away for a week, so thought that it might be best to hand it over, in case you want to try to make the required changes.
It uses the normal atan2 convention where the +X direction is 0, +Y = 90, -X = 180/-180 and -Y = -90. Your A axis would need t change that.
A variable defined near the top allows for changing to use C for the tool rotation.
Edit the INI file [FILTER] section:
Code:
[FILTER]
PROGRAM_EXTENSION = .ngc G-code
ngc = /home/andypugh/linuxcnc/dragknife
Then save this code as "dragknife", make it executable and put it in the path defined above.
Code:
#! /usr/bin/python
import re
import sys
from math import *
import linuxcnc
# Change this to alter the rotary axis letter
L = "A"
infile = sys.argv[1]
f = open(infile, 'r')
G = -99999.0
X = 0.0
Y = 0.0
oldA = -99999.0
A = 0
A2 = 0
s = linuxcnc.stat()
s.poll()
if 901 in s.gcodes:
abs_centre = True
else:
abs_centre = False
oldX = X = s.position[0] + s.g92_offset[0] + s.g5x_offset[0]
oldY = Y = s.position[1] + s.g92_offset[1] + s.g5x_offset[1]
print("(Start X %f, Y %f)" %(oldX, oldY))
for line in f:
Xf = re.match(r".*X\s*([\d\.,\+\-]+)", line)
Yf = re.match(r".*Y\s*([\d\.,\+\-]+)", line)
If = re.match(r".*I\s*([\d\.,\+\-]+)", line)
Jf = re.match(r".*J\s*([\d\.,\+\-]+)", line)
Rf = re.match(r".*R\s*([\d\.,\+\-]+)", line)
Gf = re.match(r".*G\s*([\d\.,\+\-]+)", line)
I = 0
J = 0
if Xf:
oldX = X
X = float(Xf.group(1))
if Yf:
oldY = Y
Y = float(Yf.group(1))
if If:
I = float(If.group(1))
if Jf:
J = float(Jf.group(1))
if Rf:
R = float(Rf.group(1))
if Gf:
G = float(Gf.group(1))
if G == 90.1:
abs_centre = True
if G == 91.1:
abs_centre = False
if G == 0.0 or G == 1.0:
A = atan2(Y - oldY, X - oldX) * 180/pi
elif G == 2.0 or G == 3.0:
if Rf:
mid_x = (X + oldX) / 2.0;
mid_y = (Y + oldY) / 2.0;
l2 = sqrt((mid_x - X)**2 + (mid_y - Y)**2);
if ((G == 2) and (R > 0)) or ((G == 3) and (R < 0)):
theta = atan2((Y - oldY), (X - oldX)) - pi/2;
else:
theta = atan2((Y - oldY), (X - oldX)) + pi/2;
turn2 = asin(l2 / abs(R));
offset = abs(R) * cos(turn2);
X0 = mid_x + (offset * cos(theta));
Y0 = mid_y + (offset * sin(theta));
elif abs_centre:
X0 = I
Y0 = J
else:
X0 = oldX + I
Y0 = oldY + J
A = atan2(Y0 - oldY, X0 - oldX) * 180/pi
alpha = atan2(Y0 - Y, X0 - X) * 180/pi - A
if G == 2.0:
A = A + 90
A2 = A + alpha
else:
A = A - 90
A2 = A + alpha
if (Xf or Yf) and G == 0.0:
print("G0 %s%.2f" % (L, A))
print(line),
oldA = A
elif (Xf or Yf) and G == 1.0:
if oldA != A:
print("G0 %s%.2f" % (L, A))
if not Gf:
line = "G1 %s" % line
print(line),
oldA = A
elif (Xf or Yf) and G == 2 or G == 3:
if oldA != A:
print("G0 %s%.2f" % (L, A))
line = re.sub("\n", " %s%.2f" % (L, A2), line)
print(line)
oldA = A2
else:
print(line),
