madCAM for Luthery (guitar building)

[Rodent]

I recently deployed madCAM as part of my overall CAD/CAM strategy for a new K2 CNC system. I have to say that, with the exception of one workflow, the entire process was rather intuitive and relatively pain free ... and once I discovered how to perform that non-intuitive workflow, the entire process is rather easy and straight forward


I model my design in RhinoCAD



select the tools and define their paths with madCAM



and then post the gcode. Mach3 utilizes the posted gcode files to drive the CNC just like it should




and the end result is a roughed guitar body that's ready to be finessed by hand into a playable work of art



all the best,

R

[ger21]

Very nice 1st post. Welcome the the Zone.

[svenakela]

What was the workflow you had problems with?
Either there might be an explanation or it could be a request for change if we ask for it. Enlighten me!

[Rodent]

The madCAM workflow for defining the tool paths on the forearm and gut-cuts are significantly different than the workflow used by VisualMILL/RhinoCAM. During my 30-day eval period I dropped a quick note to Joakim requesting advice on how to perform this operation, and received a nicely detailed reply the following day

I wouldn't call it a bug, just a workflow difference in how the two CAM tools define a surface region to be machined

- in madCAM I need to include the contour surface as part of my solid model, and include a contour curve for the boundary I want to cut inside of. it's easy to extract a border from the feature face

- in the other tool, only the surface face is needed

since I prefer to model my part definitions as solids, I prefer the madCAM workflow over the other method

all the best,

R

[svenakela]

R,
If you mean that you must select the boundary (Region curve) with the model, you don't have to. You can, but you can make the region on the fly when or if you need it.
As long as you get a process that is fine for your work, then it's all ok I believe.

[CbrViking]

Can you walk us through how you develop your model in Rhino in order to use MadCAM? I start with outlines generated in Autocad, import them into Rhino, offset them, generate the pockets and such, and make surfaces rather than solids. What's more efficient?

[svenakela]

Originally Posted by CbrViking Can you walk us through how you develop your model in Rhino in order to use MadCAM? I start with outlines generated in Autocad, import them into Rhino, offset them, generate the pockets and such, and make surfaces rather than solids. What's more efficient?

Was that a question to me or to Rodent?
if it was for me - I always keep my models as solids, even when I create surfaces I remake the solid to include that particular surface. With a solid you have better control of the "model body", analysis tools etc.

rhino:soliddiscussion · McNeel Wiki

The good thing with Rhino though, is that any object is accepted at the same time. You can have a solid, polygon and a loose surface together. It's very handy if you want to block a toolpath from an area to stretch out a temporary surface for example.

[Rodent]

almost all of the MadCAM toolpaths can be generated from 2D curves in this design, the exceptions being

- the top side forearm contour
- the rear side gut-cut
- the rear side heel contour (where the neck is bolted on)

I create an extruded solid from the body contour, create the 3D surface for each of the contours above, trim the body solid with the contour surface, join it all back together into a closed volume, and then generate an outline curve for the contour face.

in MadCAM, select the body solid as your material, select the tool, and then select the contour as your machined area limitation boundary.

depending on the surface contour and your material offset preferences, you may be able to skip one of the two roughing steps (i.e. go right from roughing to machining the final surface)

make sense?


svenakela - it would be interesting to learn if you have any suggestions on simplifying this workflow

all the best,

R

[CbrViking]

Thanks guys - I'll try and figure out what you said... Sorry, I'm a total newbie to both Rhino and MadCAM.

[Rodent]

Originally Posted by CbrViking Thanks guys - I'll try and figure out what you said... Sorry, I'm a total newbie to both Rhino and MadCAM.

if you already know AutoCAD, take the time to organize your layers well before migrating your work to Rhino. if you need to do any clean-up in Rhino once you data is there, take the time to do so before you go any further

I'm a novice Rhino user from the viewpoint of total hours used .... but I have been a CATIA consultant for over 10 years, and have used several other CAD packages the past 20 years. all of my composites and advanced surfacing activities provide me the foundation to know what I need to do ... then it's a simple matter of learning the workflows for a particular CAD or CAM package.

having tidy work habits that include regular backups will also go a long ways towards making your life with any CAD or CAM package easier.

all the best,

R

[svenakela]

As a note for Rodent, you cut mostly in soft materials so you can go from roughing to a fine pass. For example Z-leveling is very important if you cut in metal and next tool is prone to snapping (small, long, ball etc), the Z-level path makes next cutter work with constant depth. If you go from roughing directly to a fine path a similar tool will snap right away.
When working in soft materials though, there's not a problem if the cutting depth varies.

[CbrViking]

Svenakela - that's great advice. I do mostly wood routing, but I do have a design for a guitar bridge in aluminum that I will eventually get to.

Rodent - I recently discovered layers in Rhino and they help a lot! I use them all the time in Autocad, so it was nice to see them in Rhino.