Ok so I'm brand new to sketchUcam so bare with me. I'm also using a mac but it all seems to be going well.

I'm getting my CNC machine in the next week or so, and just playing round with designs nd the plugin.

I understand most of it (I think!) but one thing I do need to get is how to cut a dome shaped object like the one attached.

I saw a video of a wing being done which did horizontal passes that resulted in a stepped pattern on the wing, this basically took most of the material off, just leaving a bit left for a radius pass to make it a lovely smooth curve.

As you can see, nicely new to this, so I will greatly appreciate all help. Oh and as a result, use small words

 

Let's say that your dome is 2" diameter and that your bit is 1/8". Draw a square the size of your diameter, 2", plus a border of your bit diameter on the top and on the bottom, 1/8 +1/8 = 1/4. Add about an 1/8" and you have a square of 2.375x2.375. Make sure the square's left bottom corner is on the zero point of the axis' view. Put the dome in the center of the square, check the 3D option and the multipass option in the parameter window and you are set to go!

small enough words?

 

Almost

Thanks a million, it did definitely help. Although I got a bit confused about the square thing, not sure what its meant to do? Is it a 3d square or does the 3d dome sit on top of it?

I'm going to ask for a bit more help though, and you'll see my novice abilities come through now!

So the piece above, lets say has a max height of 30mm. It is 300mm long and 200mm deep with the lowest point of the curve 15mm below the top.

Lets say I've made it in these dimensions, and am happy it may be a bit smaller due to the bit diameter. It is sitting happily in the safe area box, with one corner happily at the 0 point of all axis.

Is there any chance you could go step by step what to do with the plugin to get it to generate the gcode?

Such as "Click outside cut, then click the edges, then click the pocket tool (just as an example here) and click the top side of the piece..."
You can see how lost I am now!

I don't see an option for multi pass, just a field for the depth...

Also, sketch up seems to hang when I generate the geode now that 3d is selected... I'm on a mac, will have access to a pc soon

 

I don't have a Mac, I have a PC, so that I can't tell you what to do with a Mac. I heard that there are problem with the parameter box displaying correctly with the Mac but if you have the 3d option checked I think you should be able to see the multipass option too. It's just about the 3d option.

Look at the attached .skp file. It has the dome that you've mentioned with the dimensions you posted above. You can see the square that I was talking about. The square is flat, not 3d.

 

Good point, swarfer, totally forgot to mention it.

 

Nice one! Swarfer thanks for that, very helpful.

So I draw this dome for example, with the flat square (or in this case rectangle) below it. Then choose my parameters, including multi pass and 3d and then hit generate Gcode?

No need for any cutting tools?

You guys are brilliant, I really do appreciate the help

 

Ok so it turns out Sketchup looks like it hangs when its generating the code. Takes a while which confused me.

Have a look at the code, pretty much the only Y coordinates are 5 and 205....

Is this correct? I assume its just travelling out from the front to the back repeatedly as it moves gradually down the x axis?

 

I gave it a look, and it is a clean cut path of what looks like the top surface of a simple wing. The rapids are below the surface of the cut though. If you have an overhead gantry cutter, make sure you check "overhead gantry'' in the parameters box. If you have a PP1 or PP MKII you would get a concave cut, if you have a PPIII or an overhead gantry cutter you would get what appears to be a proper top surface of a wing right up the very end where the cutter would dip below the surface and cut a deep trench diagonally from the upper right of the finished part back to where the cut started.

As far as Sketchup hanging up, 3D routing generates huge cut files, that might take anywhere from many seconds to a couple of minutes to calculate.

 

Ye it's an overhead gantry, will check if it's selected.
I presume selecting OHG will stop that trench being cut?