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Skin surface cut section leads to problem in CAM
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Hello I'm construction a wing. And i use skin surface to 'cut' the foils i need. The cuted foils outline consists of a lot of tiny lines. I used connect curves in order to get one line. Then i export it to dxf and generate the NC file with Cut2D. When i start my mill it still has all the tiny lines and it cuts along this tiny lines. Which means stop and go for my mill. this is not good for my mill and it is time consuming. So my question is. Is there an other way to get rid of this tiny lines or what else can i do to convert the these lines in to one line. I also tried right mouse click, change object type but with the same result.
Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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Workaround with Qcad
I think i found a workaround with QCad. I've imported the dxf to QCad, modified the lines to a polyline and stored it as dxf. Than i generated the G-code and it was half the lines with the QCad dxf (600 instead of 1200).
the pity is i quit QCad 2 years ago for ViaCAD. :-)
Edited by user Tuesday, October 14, 2014 8:02:52 AM(UTC)
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Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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Originally Posted by: martinwh99 Workaround with Qcad I think i found a workaround with QCad. I've imported the dxf to QCad, modified the lines to a polyline and stored it as dxf. Than i generated the G-code and it was half the lines with the QCad dxf (600 instead of 1200). the pity is i quit QCad 2 years ago for ViaCAD. :-)
You can change the lines to polyline or another type using change object type command under edit.
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Would it be possible to post one of the sections? Also, what version of DXF are you exporting as?
Tim
Edited by user Tuesday, October 14, 2014 10:28:33 AM(UTC)
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Tim Olson IMSI Design/Encore
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Tim It would be awesome to get that composite curve integrated for things like this among others that have been discussed in the past. Thanks Jason
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>:>It would be awesome to get that composite curve integrated for things like this among others that have been discussed in the past. Yes understand. For this instance I think the OP should be able to use existing tools to create a single polyline for DXF export. A polyline comes in as a single entity into AutoCAD. Tim
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>>>>>> Yes understand. For this instance I think the OP should be able to use existing tools to create a single polyline for DXF export. A polyline comes in as a single entity into AutoCAD.<<<<<<< Tim Yes a polyline comes in as a single entity composed of many little line segments. The cam software then has to stop start or change acceleration at each point on each small segment. So the less small segements the better. It's much better to have small fitted arcs than a bunch of little line segements. A almost straight line can have 5-10 segements when it's a polyline. In these cases the geometry from splines and polylines I would draw over top fitting 3 point arcs and delete all the small lines/ polylines. Then the cam profile is smooth and faster. In a lot of cases normal longer lines and or arcs and circles can take the place of all the little line segements in a polyline. Thanks Jason
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>>It's much better to have small fitted arcs than a bunch of little line segements. Does the Arc : Arcs from Curve help? This will convert a polyline into arc segments. Tim
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Sorry that it took so long for my answer. But here are my files i did some test with.
The vcp file contains a foil with some 243 control point spline. It was generated from a skin surface with cut section. If i do a select chain and change type to polylines i have 243 polylines. I've tried DXF exports with R12 and R14 both with the same result. I also tried with dwg export same result.
The txt file is the G-code file
Edited by user Monday, December 15, 2014 4:54:39 AM(UTC)
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File Attachment(s):
PS-3mm-1.vcp
(276kb) downloaded 17 time(s). PS-3mm-1.txt
(32kb) downloaded 6 time(s). PS-3mm-1.dxf
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Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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I've been playing around and what i found is if i first convert the lines to polylines, then i do join Curves on these polylines, will give me an NC file with 2000 lines instead of 30000. So i will see this week how my CNC behaves with this file. @Tim This is a funny function the Arcs from Curve. If i want to do a puzzle one day out of my drawings. I will try this one. :-) No sorry that did not serve my needs.
Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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I've done the CNC cut and it is still the same. A lot of tiny steps and the machine slows down with this stop and go. Unfortunately this is 70% of the cad work i'm doing, - making some cut section from skins and cut them on my cnc mill. Attached is the file i have been working on.
A college of mine uses rhino i think and he has no problem at all using the same (Cut2d) tool for generating the nc file. So, what am i doing wrong? Can someone please help me? Or am i using the wrong cad tool for this stuff? That would be hard, because i spend now 2 years learning and working with ViaCAD.
I have a 3d file generated from a dxf export for milling, i hope this will work. I'll try it within the next week.
File Attachment(s):
Ps-3mm.dxf
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I imported the dxf and the whole profile of one of the pieces is coming as one line when in fact you have vertical lines, horizontal lines, and curves making the profile. I've seen that before which is caused by the program that exported it. One way to fix it is to break the profile and convert the curves to interpolate splines. If the exporting program can export .iges, you can have the original approach when you made the profile. Obviously, you didn't design it with tiny tiny lines but the exporter is doing it that way when doing a curved line and moreover doing the entire profile as one line. Maybe Tim has another suggestion.
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Originally Posted by: martinwh99 I've done the CNC cut and it is still the same. A lot of tiny steps and the machine slows down with this stop and go. Unfortunately this is 70% of the cad work i'm doing, - making some cut section from skins and cut them on my cnc mill. Attached is the file i have been working on. I have a 3d file generated from a dxf export for milling, i hope this will work. I'll try it within the next week.
Martin
Use the arcs from curves tool on the splines before anything else. Select the tool and hold down shift and select a bunch of splines one by one and it will create a arc fit to those splines. So pick 20-30 at a time to get smooth arcs. The key is to select several with the shift key vs selecting all the lines and splines. You can set the tolerance in the top before using the tool.
The Cnc equipment used circular interpertation on arc so it slows acceleration but doesn't stop like on lines. Line are stop start end points. So even if you have 20 some arcs and a few lines in the linear areas l after changing all the splines it should cut ok
Regards
Jason
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Hello
I made some test with exports and generating g-code. Here is what i have done. I' have copied a part of my drawing, just one line part.
1. Export and generate g-code (1_test_unchanged)
2. draw an interpolated spline over the original, Export and generate g-code (2_test_manInterpolySpline)
3. take the original and done a join curve, and generate g-code (3_test_joincurve)
4. take the result from 3 and did a change object to interpol. Spline (4_interpolSpline)
The result for me is disappointing they are all the same except number 2.
Unfortunately i did not find the arcs from curves tool so i could not try this one.
What else can i do?
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tests.zip
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Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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Martin The arc from curve tool is in the arc toolbar last tool. This tool will give you what you need. Regards Jason
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Originally Posted by: Guest Martin The arc from curve tool is in the arc toolbar last tool. This tool will give you what you need.
Thanks Jason i think this helped see the g-code file. On the weekend i will try this with milling. once again thanks allot.
File Attachment(s):
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Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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The way things are sounding to me, Check the direction of the lines(splines). I'm going to assume the cnc program is for "hobby"- that is, it's not running on a Mazak 250,000buck machine correct? Captain Canardly>johnny
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Second try but this time with an elevator mold. Thanks to PowerPack simplify profile function and the help of Tim. The new mold i want to mill has only 15600 lines and this one is bigger than the former one. With in a fortnight i will mill this one. Will see if there are still so many stop and go's
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Martin Krueger ViaCAD ProV9, Cut2D, Cut3D _myMill self made CNC milling-machine
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