Cutting donuts

[sintratech]

I have tried everything I can think of. I am cutting centering rings for model rockets. They resemble a donut I need to cut the center circle first then the outter circle or else it will throw the whole centering ring off the table . Does anyone know how to cut the inner circles before the outter circles? I am using autocad 2005 and Mach 3

[jonbell78]

you should be able to just swap the G code so you cut the inner first. You should be able to use a g code editor you do it, or just use a text editor.

[ger21]

You didn't say in the PM's, but I'm assuming you're using LazyCAM? Does LazyCAM let you specify cut order by layer? You could try ACE converter to create code. It's free, from www.dakeng.com If you put each circle on it's own layer you can specify cut order by layer. You can also buy a CAM program like SheetCAM.

[sintratech]

Im guessing its lazy cam? When I go to import DXF I click it and I have the option of a layer? I am really new to all this I dont know what im doing. In cad how do I select the thickness im going to cut or how do I do it in mach 3? I wish someone lived close and could come help me set everything up

[ger21]

In AutoCAD put each cut on it's own layer. Then you should be able to assign cutting depth and order by laer when you import the .dxf
What version of Mach3 are you using? Does it say import .dxf, or LazyCAM in the file menu?

[gmfoster]

Originally Posted by sintratech Im guessing its lazy cam? When I go to import DXF I click it and I have the option of a layer? I am really new to all this I dont know what im doing. In cad how do I select the thickness im going to cut or how do I do it in mach 3? I wish someone lived close and could come help me set everything up

There are probably a hundred ways to do this but one of the easier ways would to just draw one circle in your cad. Import it and make your cut, then scale the same circle and make your next cut.

Another way is to make two individual drawings of one circle each then cut the part as if it was two parts. Load and cut the drawing for the first circle then load and cut the second circle.

But it is pretty easy to select cutting paths and layers in lazy cam.

Have you taken the time to watch the videos that Art has set up on using it. They are pretty through.

Even just sitting and writing the Gcode for two circles direct in Gcode (handcoding) should be rather trival for such a simple part.

Another way is it sounds as of the gcode being generated is working you just need to change which circle is being cut first. Just take an editor and cut out your first circle and paste it after the code for your second circle.

Another way is to make each circle a seperate layer and go from there.

My suggustion is rather simple and that is
1. Watch Art's video's.
2. Study the gcode commands in general a little.
3. Look at the code you have and understand what it is doing on a line per line basis, At that point it will be trival to make your changes and you can probably do all this in less than 4 hours and the knowledge will stay with you for years.


If all else fails post your code here and someone will help you edit it.(Gcode)

Garry

[sintratech]

Hi guys thanks for your help. First Ger21 in file menu it says import dxf not lazycam. I can kinda get an idea what is being cut at what time by looking at lines being cut (gcode) Let me post my dxf file to you guys and maybe you can help me. I see I can delete lines 10-27,44-59, and 76-90 and it takes away the outter circle cutting. I even tried to save just inner circles as a single file and then have outter circles as second file but they didnt line up right. So let me post the dxf file then maybe you guys could help me edit it ?

[ger21]

When you import the .dxf, click on the layer button and you should be able to set the cutting order, if the rings are on different layers.

[sintratech]

I never have used layers before in autocad. I can redraw the circles. Can you tell me in detail how to use layers? I was looking in cad and I saw where I can change the colors of the layers but other than that I am not sure what to do?

[ger21]

Type "layer" in AutoCAD to get to the layer manager. Create new layers and name them accordingly. either change to the correct layer before drawing the new circles, or change the layer using the properties window for each circle. You can also change the objects layer by selecting it, and then choosing the layer you want it on in the Layer drop down list.

[gmfoster]

Deleted as duplicate

[gmfoster]

Originally Posted by sintratech I never have used layers before in autocad. I can redraw the circles. Can you tell me in detail how to use layers? I was looking in cad and I saw where I can change the colors of the layers but other than that I am not sure what to do?

I see that you are trying to cut several circles in one file. That will work but what I was thinking was that you were trying to do was start simple and build up yor knowledge.

I would draw one donut and get it to cut properly and build my knowledge from there. In fact thats the neat thing about this CNC you don't really need to draw all the circles you can just draw one then move your reference to cut all the additional one.

I ask again have you watched the videos for mach? Art has some very good ones and I think the one on Lazy cam is outstanding.

Layers is probably th easiest way to do this and you don't have to redraw. Just select either all the inner or all the outer and change the layer attribute for the ones you select. I don't have the funds for Auto Cad but I can do this even with my 15 dollar demo version of Vector..

Another trick a lot of people do with this kind of thing is to leave small tabs on the parts then break them out more or less like a plastic model kit.

Garry