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# simple parallel finish toolpath example
# Anders Wallin 2014-02-23
import time
from opencamlib import ocl, camvtk
import ngc_writer # G-code output is produced by this module
# create a simple "Zig" pattern where we cut only in one direction.
# the first line is at ymin
# the last line is at ymax
def YdirectionZigPath(xmin,xmax,ymin,ymax,Ny):
paths = []
dy = float(ymax-ymin)/(Ny-1) # the y step-over
for n in range(0,Ny):
path = ocl.Path()
y = ymin+n*dy # current y-coordinate
if (n==Ny-1):
assert( y==ymax)
elif (n==0):
assert( y==ymin)
p1 = ocl.Point(xmin,y,0) # start-point of line
p2 = ocl.Point(xmax,y,0) # end-point of line
l = ocl.Line(p1,p2) # line-object
path.append( l ) # add the line to the path
paths.append(path)
return paths
# run the actual drop-cutter algorithm
def adaptive_path_drop_cutter(surface, cutter, paths):
apdc = ocl.AdaptivePathDropCutter()
apdc.setSTL(surface)
apdc.setCutter(cutter)
apdc.setSampling(0.04) # maximum sampling or "step-forward" distance
# should be set so that we don't loose any detail of the STL model
# i.e. this number should be similar or smaller than the smallest triangle
apdc.setMinSampling(0.01) # minimum sampling or step-forward distance
# the algorithm subdivides "steep" portions of the toolpath
# until we reach this limit.
# 0.0008
cl_paths=[]
n_points=0
for path in paths:
apdc.setPath( path )
apdc.run()
cl_points = apdc.getCLPoints()
n_points = n_points + len( cl_points )
cl_paths.append( apdc.getCLPoints() )
return (cl_paths, n_points)
# this could be any source of triangles
# as long as it produces an ocl.STLSurf() we can work with
def STLSurfaceSource(filename):
stl = camvtk.STLSurf(filename)
polydata = stl.src.GetOutput()
s = ocl.STLSurf()
camvtk.vtkPolyData2OCLSTL(polydata, s)
return s
# filter a single path
def filter_path(path,tol):
f = ocl.LineCLFilter()
f.setTolerance(tol)
for p in path:
p2 = ocl.CLPoint(p.x,p.y,p.z)
f.addCLPoint(p2)
f.run()
return f.getCLPoints()
# to reduce the G-code size we filter here. (this is not strictly required and could be omitted)
# we could potentially detect G2/G3 arcs here, if there was a filter for that.
# idea:
# if a path in the raw toolpath has three points (p1,p2,p3)
# and point p2 lies within tolerance of the straight line p1-p3
# then we simplify the path to (p1,p3)
def filterCLPaths(cl_paths, tolerance=0.001):
cl_filtered_paths = []
t_before = time.time()
n_filtered=0
for cl_path in cl_paths:
cl_filtered = filter_path(cl_path,tol)
n_filtered = n_filtered + len(cl_filtered)
cl_filtered_paths.append(cl_filtered)
return (cl_filtered_paths, n_filtered)
# this uses ngc_writer and writes G-code to stdout or a file
def write_zig_gcode_file(filename, n_triangles, t1,n1,tol,t2,n2, toolpath):
ngc_writer.clearance_height= 5 # XY rapids at this height
ngc_writer.feed_height = 3 # use z plunge-feed below this height
ngc_writer.feed = 200 # feedrate
ngc_writer.plunge_feed = 100 # plunge feedrate
ngc_writer.metric = False # metric/inch flag
ngc_writer.comment( " OpenCAMLib %s" % ocl.version() ) # git version-tag
# it is probably useful to include this in all g-code output, so that bugs/problems can be tracked
ngc_writer.comment( " STL surface: %s" % filename )
ngc_writer.comment( " triangles: %d" % n_triangles )
ngc_writer.comment( " OpenCAMLib::AdaptivePathDropCutter run took %.2f s" % t1 )
ngc_writer.comment( " got %d raw CL-points " % n1 )
ngc_writer.comment( " filtering to tolerance %.4f " % ( tol ) )
ngc_writer.comment( " got %d filtered CL-points. Filter done in %.3f s " % ( n2 , t2 ) )
ngc_writer.preamble()
# a "Zig" or one-way parallel finish path
# 1) lift to clearance height
# 2) XY rapid to start of path
# 3) plunge to correct z-depth
# 4) feed along path until end
for path in toolpath:
ngc_writer.pen_up()
first_pt = path[0]
ngc_writer.xy_rapid_to( first_pt.x, first_pt.y )
ngc_writer.pen_down( first_pt.z )
for p in path[1:]:
ngc_writer.line_to(p.x,p.y,p.z)
ngc_writer.postamble() # end of program
def vtk_visualize_parallel_finish_zig(stlfile, toolpaths):
myscreen = camvtk.VTKScreen()
stl = camvtk.STLSurf(stlfile)
myscreen.addActor(stl)
stl.SetSurface() # try also SetWireframe()
stl.SetColor(camvtk.cyan)
myscreen.camera.SetPosition(15, 13, 7)
myscreen.camera.SetFocalPoint(5, 5, 0)
rapid_height= 5 # XY rapids at this height
feed_height = 3
rapidColor = camvtk.pink
XYrapidColor = camvtk.green
plungeColor = camvtk.red
feedColor = camvtk.yellow
# zig path algorithm:
# 1) lift to clearance height
# 2) XY rapid to start of path
# 3) plunge to correct z-depth
# 4) feed along path until end
pos = ocl.Point(0,0,0) # keep track of the current position of the tool
first = True
for path in toolpaths:
first_pt = path[0]
if (first == True): # green sphere at path start
myscreen.addActor( camvtk.Sphere(center=(first_pt.x,first_pt.y,rapid_height) , radius=0.1, color=camvtk.green) )
pos = ocl.Point(first_pt.x,first_pt.y,first_pt.z) # at start of program, assume we have already a rapid move here
first = False
else: # not the very first move
# retract up to rapid_height
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,pos.z),p2=(pos.x,pos.y,feed_height),color=plungeColor) )
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,feed_height),p2=(pos.x,pos.y,rapid_height),color=rapidColor) )
# XY rapid into position
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,rapid_height),p2=( first_pt.x,first_pt.y,rapid_height),color=XYrapidColor) )
pos = ocl.Point(first_pt.x,first_pt.y,first_pt.z)
# rapid down to the feed_height
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,rapid_height),p2=(pos.x,pos.y,feed_height),color=rapidColor) )
# feed down to CL
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,feed_height),p2=(pos.x,pos.y,pos.z),color=plungeColor) )
# feed along the path
for p in path[1:]:
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,pos.z),p2=(p.x,p.y,p.z),color=feedColor) )
pos = ocl.Point(p.x,p.y,p.z)
# END retract up to rapid_height
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,pos.z),p2=(pos.x,pos.y,feed_height),color=plungeColor) )
myscreen.addActor( camvtk.Line(p1=( pos.x,pos.y,feed_height),p2=(pos.x,pos.y,rapid_height),color=rapidColor) )
myscreen.addActor( camvtk.Sphere(center=(pos.x,pos.y,rapid_height) , radius=0.1, color=camvtk.red) )
camvtk.drawArrows(myscreen,center=(-0.5,-0.5,-0.5)) # XYZ coordinate arrows
camvtk.drawOCLtext(myscreen)
myscreen.render()
myscreen.iren.Start()
if __name__ == "__main__":
stlfile = "../../../stl/gnu_tux_mod.stl"
surface = STLSurfaceSource(stlfile)
# choose a cutter for the operation:
# http://www.anderswallin.net/2011/08/opencamlib-cutter-shapes/
diameter=0.25
length=5
#cutter = ocl.BallCutter(diameter, length)
cutter = ocl.CylCutter(diameter, length)
#corner_radius = 0.05
#cutter = ocl.BullCutter(diameter, corner_radius, length)
#angle = math.pi/4
#cutter = ocl.ConeCutter(diameter, angle, length)
#cutter = cutter.offsetCutter( 0.4 )
# toolpath is contained in this simple box
ymin=0
ymax=12
xmin=0
xmax=10
Ny=40 # number of lines in the y-direction
paths = YdirectionZigPath(xmin,xmax,ymin,ymax,Ny)
# now project onto the STL surface
t_before = time.time()
(raw_toolpath, n_raw) = adaptive_path_drop_cutter(surface,cutter,paths)
t1 = time.time()
# filter raw toolpath to reduce size
tol = 0.001
(toolpaths, n_filtered) = filterCLPaths(raw_toolpath, tolerance=0.001)
t2 = time.time()-t_before
# output a g-code file
write_zig_gcode_file( stlfile, surface.size() , t1, n_raw ,tol,t2,n_filtered, toolpaths )
# and/or visualize with VTK
vtk_visualize_parallel_finish_zig(stlfile, toolpaths)
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