Slicing File Format Issues

[Brady Watson]

Ed,
If your desire is to have 'hollow' models cut on the bot, then the 3D file will need to be offset to the inside of the outer skin in order to achieve this. You should be able to do this easy enough in Cobalt, although there can be more to it than meets the eye - like stitching up the edges where the front meets the back side skin etc. Since you are working with solids, this should be a much easier task than attempting to do this with meshes.

With a properly offset model, Cut3D will respect the void center sections, like the hollow part of the turbine housing etc. Right now, your models are like a veil draped over 3D points. You need to determine the inner geometry of your parts and in conjunction with the outer skin, join them together to create the hollow model.

Your model looks like it is on the right track, however - you have some more work to do, if you want a hollow model off of the CNC. Offset what you have & double check the new dimensions. There is always more than one way to skin a cat...or a plane - for instance, you could section up the parts in CAD, then take a cross section & 2 rails and sweep each section around to create a hollow closed shape. If you know your material thickness, then you can omit slicing altogether in Cut3D, and just prepare models of an appropriate thickness & pull them in one at a time to toolpath. There are other ways as well...

Also, keep in mind that Cut3D is a very basic 3D CAM program that gives you limited control over toolpaths. There are other CAM packages out there that would yield higher quality 3D cuts and more control over the process as a whole.

-B

[Flite-Metal]

Brady,

As stateed, these drawings were done as surfaces, not solids. I need to revert them to solids with AV software using the
solids/surfaces tools to extend the surface to a solid per the AV documentation.

This appears to be a straight forward conversion which is a standard function of AV's drawing and editing baseline product.
AV told me all their products use the same drawing and editing core functionality and tools.

So, I have the original .ar files for my fuselage, inboard, outboard nacelles, and the rear sheath containing the rear turret.

All of these are surfaces. Surfaces do have an X, Y, Z defining their shapes to the "thickness" of the surface. Therefore
the surfaces to solids functions of the software to fill the interor of shape to a solid.

I only have a Cobalt Share program and the demo version of Argon. Both permit opening, viewing, editing...but no saving
to a new file name when edited.

Tom Willis says Cut3d will mill the outside surfaces when sliced and not the interior space if we do nothing at all and simply
mill what we have now.

If that fails, I need someone's assistance to up-convert our surfaces to a solid.

Cut3d will do what we need done. That is the easy part for the future when we have nothing but solid geometry instead
of surfaces we have now. Interior of our shapes will be hot wired to retain greatest strength.

[tomwillis]

Ed - first let me say - I am no expert on Cut3d. Brady is correct - Cut3d is limited in it's tool pathing. Cut3d will still treat your hollow sections as hollow in the exhaust sections - as shown in those pics. It may get you close to where you need to go....but after reviewing this to get a model trust worthy of flying - you most likely will need the interior dimensions...so it's not just a 'skin and remodel it accordingly. One section of this mesh protrudes right beyond the edge into the btm - as if the CAD designer just dropped it in. My guess is - it would need a fillet taper where it meets the other part of the model.
tom

[Flite-Metal]

Somehow in my attempt to keep my Q & A simple without baggage outside the scope of our current milling issue, I have lost creditability in that you guys don't seem to understand this is not our first rodeo...

Everything relative to this entire project has already been engineered. All we are in need of is milling some sections to make it less labor intensive to achieve the detail of compound and convex shapes and replicate the effort for multiples of the same items required... There are two 1:8.7669 airframes with one of the two created so it can replicate two different airframes...

The entire mechanical functionality of this project is based on an inner truss with a pair of internal truss attached internally to permit all stresses and mechanical functions to be strong and endure the stresses of flight.

The Dow High Load 60 Styrofoam shape which "replicates" the Boeing B-47 Stratojet is a facade with virtually no function except to endure abuse of flying and handling. I have been making these using hot wiring of individual sections from nose to tail for twenty plus years. Doing in CNC is faster and less expensive with greater accuracy.

To achieve this I have gathered well over 30 gig of documentation including multiple view artist renderings since there are only two Boeing engineered drawings in existance. When this project began three and one half years ago there were fewer than 10 Google returns from a search. Today there are well over a thousand as a result of the spiders we put into motion doing online research. We have over 100 million online references to our project. Many of the returns found are explicitly ours. This is not unusal as that is how web bots function in search engines and one search engine to another.

We have everything engineered from landing gear to articulated rear cannon to four flying radar seeking drones which are released from one config of this airframe. Another does a lofted release of an atomic bomb with parachute delay of its delivery to target while the airframe escapes the blast wave.

Competing in FAI F4C is a tuff task. Of the USA entries we have seen only a few earn as close to 13th or 15th place since 1981. My desire is to effect change to that.

That's a short hand tour of our two 1:8.7669 Boeing B-47 airframes with three different configurations:

[Flite-Metal]

Here are the three configs of our B-47's.

Because the original files were generated in Ashlar-Vellum as surfaces instead of solids, I am going to see if the surface thickening
to a solid editing function will provide a cure to what has haunted this project since the originals arrive here...two months ago. We
have been met with constant contradition since they arrived. Tom Willis told me about the Surface to Solid editing function so we
are going to the gentleman working with us at Ashlar-Vellum to order the retiree version of the software. We were planning to add
this later as every $ spent outside of planned elements puts us at a disadvantage down stream.

[Flite-Metal]

I appreciate everyone's contributions and feedback. This project is literally weeks from completion given we can mill a few parts to
eliminate having to do it the old fashion way. One would imagine this would have been simpler...it isn't folks, it isn't as this witnesses
as my second session within ShopBot's forum.

Mr. Zellmer at ShopBot is working with me to resolve an easier to digest pathway using Cut3d to negate having to go to the moon
to get across the street.

Thanks for the help guys.

Geez, would certainly be nice if the editor would stay functional instead of shutting down after ten minutes. Makes detailed text and
examples difficult to manage.