how bout an auto tab feature?

 

Mark, that's really cool! Thanks for experimenting, you've shown everyone what can be achieved, it's just very time consuming at the moment. I've created similar gcode, but i've not actually cut any pockets yet. Your photos show just how accurate the pockets could be.

I used the offset tool when I was doing my tests and found that it struggles with certain shapes (in SU6 anyway). The latest idea that i'm playing with is shown below. This path was created by drawing a shape, then drawing a horizontal line above the shape and duplicating it over the top of the shape multiple times. I then intersected the lines and the shape, then deleted lines to produce the zig-zag path.

I figured that if pockets were created like this then there wouldn't be any 'travelling' involved like there is when using the offset method. The problem I have now is that the zig-zag path is made of segmented lines rather than a single continuous line. I've been looking for Ruby scripts which will convert the path to a continuous line, and I think 'closeopens.rb' from Smustard might work. The trouble is that there are several similar scripts available and they all cost $20 each. I tried Weld.rb but that didn't work.

If anyone knows how to convert a series of broken lines into a continuous line (that the centerline tool will follow sequentially) then I think we will have a solution.

Si. Attached files

 

Another neat idea would be a direct draw feature, or convert line to cut.
This would be handy in making line cuts for things like templates, or line type text.

This should be easy, as I know you can modify the g-code after it's auto drawn, just make a way to manually put it down / direct covert w/ out offset.

 

I did have a line around the perimeter of the pocket like you suggest, but I removed it so you could see the zig-zag pattern. I was also spacing the lines at half the diameter of the bit. It's good to know we're both approching the idea the same way .
If you have any of the 'Cad cleanup' scripts from smustard that you could test on a similar series of segmented lines then that would be great.

A feature i'd like to see in the future is an option to change tools (bits) during a cutting operation. For example, use a 1/16th bit to cut detailed parts, a 1/8th bit for cutting larger parts and pockets, and maybe a swap to a standard drill bit for drilling operations. It's possible to do this at the moment, but it requires generating and loading different gcode files for each different bit size.

 

The basic idea would be to make a single line cut, or the ability to draw the exact path you want the bit to take.

This could kill two birds with one stone, because if you could also control the depth of cut you could also draw the pocket cut area as you want it cut, as shown above (but not using the centerline tool).

 

tvcasualty, I think I follow what you mean. If for instance the centerline tool let you choose a depth as a measurement rather than a percentage of the material thickness, then you could choose a centerline depth of 8mm if you were using 6mm foam which would produce a cut. In effect a centerline with a depth of >100%.

 

Mark, I'll have a look at the 'repair broken lines' script, i'd forgotten about that one. I know what you mean about Christmas, i'm in exactly the same postion. I may take a gamble and try the closeopens script though.
From the script description : 'The two closest open segments will be joined with a new line segment. Then, the next two closest lines will be joined with a line segment, and so on until no more open segments can be joined.'
This sounds like it joins the lines sequentially, which might produce the toolpath that i'm trying to achieve.
I think this is the kind of algorithm that the centerline tool needs to use to optimize the gcode it creates.

The tool changing idea is not really important, It was just an idea I thought i'd throw out there. I think I can do it manually at the moment by pausing Mach, clicking the 'home printer' button, jogging the Dremel manually and then clicking the 'send printer home' button once i've changed the tool and then clicking 'print'. The only problem is stopping the gcode in the right place. Do you know if there is a 'stop' or 'pause' command that can be inserted manually into the gcode?

 

Ok, I think i've found a workaround for producing a decent 'pocket toolpath'.

Using the same 'intersect' method I mentioned earlier to create a toolpath manually, If you select all the lines and keep applying the weld.rb script, eventually you get a sequential path. I tried a few different pocket shapes and they all varied in the number of times the script needed applying. I've made a custom hotkey now so that the script is appied when I press W on my keyboard. Once the line is sequential you can click on it with the centerline tool and the whole path turns green (rather than just a segment of it).

Here's the toolpath for a random shape I drew to test the theory.

Attached files

 

The peck drilling option would be great.


Being able to specify a cutting order would be a nice feature to add.

 

Mark, i've not tried cutting a pocket yet, it was about 2am when I finally figured out how to do it. I didn't think the family would appreciate me running the Phlatty at that time in the morning. I'll give it a shot later today and see what happens.

Another process i've looked into is 'part nesting optimization'. This is where the computer analyzes the groups of parts within the safe cutting area and automatically rearranges them to fit within the area to produce as little waste as possible. There are complex dedicated programs such as 'ProNest' which is used in the sheet-metal cutting industry, and certain CAD software such as TouchCAD that is specifically designed for unfolding 3D models and producing nests. Again, this would be great see as an option in the future but i'm just posting my thoughts and throwing ideas out there at the moment.

Si.

 

I've been playing with the centerline tool tonight and got some results that i'm really happy with. I've used the methods I mentioned earlier in this thread to pocket and centerline some 6mm depron.

My first test was great apart from the fact I didn't realise that text would need to be mirrored before generating the gcode

Anyway, here are some photos of my results. I used the standard 1/8" bit and ran the phlatty at 40ipm on both the x and y axes. The first test (not mirrored) took just over 7mins to process. The 2nd test which was a file containing the 2 mirrored layouts took 11mins 19secs.





If anyone's interested in seeing the Sketchup or Gcode files then let me know and i'll upload them.

Cheers,
Si.

 

I would like to see them

 

Me too, "milling" a depron airframe is something that I am very interested in doing, (after I get my phlatbonz kit and assemble it).
Dave