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### Author Topic: LCAM Processing of polylines from DXF  (Read 3026 times)

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#### pchumphry

• 13
##### LCAM Processing of polylines from DXF
« on: June 19, 2008, 03:11:38 PM »
Sometime LCAM generates quite  efficient  G code when processing a polyline (Only a single Z movement at the start/end of the polyline- the Polyline is treated as a single chain.)
Other times the G code generated is very inefficient, The Z axis goes up and down like  a Yo-yo back  to the release plane between every component part of the  polyline, and the polyline  is treated as multiple ( often tens of) separate chains.

As in each cast the polyline consists only of arcs and straight line segments, what then is the difference that triggers the different behaviour by LCAM?

Is there anyway of ensuring LCAM treats a polyline as a single chain? is it a function of the complexity of the polyline?

#### da21

• 87
##### Re: LCAM Processing of polylines from DXF
« Reply #1 on: June 19, 2008, 05:32:01 PM »
chances are if you look very closely at the polyline and zoom in ,  you'll find breaks or lines crossing a small amount at a corner etc  , polylines need to be one complete line , you need to make sure the polyline is clean and tidy etc

Dave

#### pchumphry

• 13
##### Re: LCAM Processing of polylines from DXF
« Reply #2 on: June 20, 2008, 08:08:03 AM »
Dave,

My drawing program (Turbocad 12v5) checks and will not let you create a polyline if segments overlap/don't join in its view. (I do not know to what precision it does this check.)

However I have found the solution!

LCAM autocean/loading options were set to a connecting line tolerance of .001 units (Which are mm in my case). This is well above any practical machining precision of my equipment. Setting this figure to .01 units meant Lcam saw the polyline as single chain at last. Will save a bit of wear and tear on the Z axis.

Best  regards

Pete

#### Hood

• 25,835
• Carnoustie, Scotland
##### Re: LCAM Processing of polylines from DXF
« Reply #3 on: June 20, 2008, 08:34:45 AM »
Thanks for posting the cure, it will help others in the future if they have the same problem.
Hood

#### da21

• 87
##### Re: LCAM Processing of polylines from DXF
« Reply #4 on: June 20, 2008, 01:57:40 PM »
Glad you found it Pete , this effect happens with any cad program if your not careful , guess how i found out ! ha ha

Dave