Cnc Software Question

[P90]

I'm a total noob at CNC. I've read through all the threads here and the one linked from here to the Gear page. I had some experience with AutoCAD at school years ago.

Is there a piece of software where I can layout on my home PC in 2-D the exact dimensions of what I need, then bring a file on a disk (CD) to a shop with a CNC, insert the disk and have it carve out what I need on a piece of lumber (which I would also supply). I would presume the most popular CNC's for this seem to be Haas or Fadal?

What software might allow me to layout the 2-D cuts at home, and bring the disk to a CNC shop?

[Reaper]

I don't know what software Haas or Fadal might be using to operate - they may just run off a straight *.nc file. The primary toolpath software that I've seen is Mastercam, but that's not really something you'd use at home (fairly expensive, and not very easy to use). I also think that Mastercam has to be configured to your particular machine's specs (ie, you need to know the right numbers to set up the tools before it lays down paths with them, or all your dimensions are going to be off).

Most of the toolpath software packages will also have 3-D positioning for the head of the cutting tool - it's not likely just going to punch out the outline in a clean sweep, especially on something as thick as a guitar, and is probably going to require a couple of passes.

You best bet? Use a CAD file, and let them convert it. If you know of a place, call and ask (heh, they'll for sure be the best source for answers to what you've just asked).

NB: my experience in this stuff is a few years out of practice, so if I've said anything wrong here, and stepped on my crank, please speak up.

[GuitarEng]

Most any CNC shop will be able to run toolpaths off of dwg or dxf files. I use Rhino CAD/CAM with my CNC machine and have been very happy with it (I use MasterCAM, Rhino, SolidWorks, and AutoCAD at my day job). I've found Rhino is better than AutoCAD for artistic designs...AutoCAD is more for the mechanical/architectural design. Rhino has great surfacing capabilities...I'll use this for doing carved surfaces like necks & bodies.

Haas and Fadal are both popular machines because they have decent spindle speeds (up to about 15,000 rpm), tool changers, and the accuracy of a low end metal working machine (they will generally hold .001"...which is very good for woodworking).

You could probably pick up a very basic CAD program at Best Buy or something for around $100 (I believe Rhino is about $600).

If you have a design (digital or not), I would be happy to work something out with you - just let me know.

I'm a total noob at CNC. I've read through all the threads here and the one linked from here to the Gear page. I had some experience with AutoCAD at school years ago.

Is there a piece of software where I can layout on my home PC in 2-D the exact dimensions of what I need, then bring a file on a disk (CD) to a shop with a CNC, insert the disk and have it carve out what I need on a piece of lumber (which I would also supply). I would presume the most popular CNC's for this seem to be Haas or Fadal?

What software might allow me to layout the 2-D cuts at home, and bring the disk to a CNC shop?

[P90]

Most any CNC shop will be able to run toolpaths off of dwg or dxf files.

Thanks! So what I need to do next is get a software app which will produce .dwg/.dxf files? Is AutoCAD a defacto standard? (You can get older versions of AutoCAD cheap on Ebay)

BTW, which Fadal/Hass machines are the most popular for luthery? What working envelope? I'm guessing the VMC2216 or VMC4020 for the Fadal or the VF1 or VF2 for the Haas?

http://www.fadal.com/?id=711

http://www.haascnc.com/VMC_MODEL_20IN.asp#VMCTreeModel

Edited March 20, 2007 by P90

[GuitarEng]

Yep, get something that will export dxf files. AutoCAD is not really a standard anymore...but their file format is a standard. Most engineering/design places are now using something like SolidWorks, SolidEdge, or AutoDesk Inventor. These are mid-level parametric modeling packages that work great for building parts & assemblies in 3D....cost on these is around $5000 per seat whereas I purchased Rhino & RhinoCAM together for $1600. MasterCAM is nice, but it also runs expensive...about $10k to start.

Fadal 4020's are a popular model, a lot of makers use these machines. They also have a 15,000 rpm spindle which helps when cutting inlay, etc. A fadal will run you about $85k. I think the real justification for a machine like a Fadal is the quantity of parts that you are running. If you are only making one or two guitars a day, a Fadal is a much bigger machine than you probably need. A good starter machine (such as a K2) is available for about 10% of the cost of a Fadal....you just have to take smaller passes with the smaller machine. (I have a K2 at home)

Let me know if I can help you out.

Most any CNC shop will be able to run toolpaths off of dwg or dxf files.

Thanks! So what I need to do next is get a software app which will produce .dwg/.dxf files? Is AutoCAD a defacto standard? (You can get older versions of AutoCAD cheap on Ebay)

BTW, which Fadal/Hass machines are the most popular for luthery? What working envelope? I'm guessing the VMC2216 or VMC4020 for the Fadal or the VF1 or VF2 for the Haas?

http://www.fadal.com/?id=711

http://www.haascnc.com/VMC_MODEL_20IN.asp#VMCTreeModel

[P90]

Thanks! I went to the K2 website and they seem to be marketing their KG-3925 toward luthiers. Here's a FAQ page with links to a video and software demo near the bottom:

http://www.k2cnc.com/FAQ_GuitarMaking.asp

Also - moderators - should this be moved to the tools & shoptalk forum? (I dont mind)

[GuitarEng]

Thanks! I went to the K2 website and they seem to be marketing their KG-3925 toward luthiers. Here's a FAQ page with links to a video and software demo near the bottom:

http://www.k2cnc.com/FAQ_GuitarMaking.asp

Also - moderators - should this be moved to the tools & shoptalk forum? (I dont mind)

That's the machine I have - I got it with the 8" Z and the limit switches. My only complaint is that they didn't provide hardly any info on the machine itself & basic operation. It wasn't hard to figure it out (I called them)...but it would have been nice to have something to go by!

[ToneMonkey]

I get some things laser cut occassionally and when I do, although they accept dxf and dwg files, they cannot accept drawings with splines on them. For the outline of a guitar body (resonator), I draw it with splines and then do as many arc's as it takes to go over the outline (which often helps to smooth everything out).

Not sure if CNC is the same, but it will be worth checking before giving them the drawings.

Kaj

[P90]

they cannot accept drawings with splines on them.

Tonemonkey - could you explain? Do you mean something like an LP carved top?

GuitarEng - where are you located?

Also (anyone) this is a good animated demo of Rhino:

http://www.k2cnc.com/videos/GuitarProjectw...thCallouts.html

Bottomline: if I were to invest in just *ONE* software package, would Rhino be the one? ...that would allow me to model the guitar AND then bring the dwg file (and the wood) to a shop w a K2/Haas/Fadal?

[Reaper]

they cannot accept drawings with splines on them.

Tonemonkey - could you explain? Do you mean something like an LP carved top?

GuitarEng - where are you located?

Also (anyone) this is a good animated demo of Rhino:

http://www.k2cnc.com/videos/GuitarProjectw...thCallouts.html

Bottomline: if I were to invest in just *ONE* software package, would Rhino be the one? ...that would allow me to model the guitar AND then bring the dwg file (and the wood) to a shop w a K2/Haas/Fadal?

I'll let GuitarEng answer that last one, but just my two cents on the CAD packages: SolidEdge is the standard CAD program at our school, and frankly, most mech-types curse it. I had to use it myself for the first-year drafting course, and I'm glad I don't have to go back to it ever again. It's a pain in the ass to use, and I found that it was generally weaker than some of its bretheren.

Not meaning to butt in, but WAY too many bad experiences with that program to be silent and still be able to maintain my conscience.

[GuitarEng]

they cannot accept drawings with splines on them.

Tonemonkey - could you explain? Do you mean something like an LP carved top?

GuitarEng - where are you located?

Also (anyone) this is a good animated demo of Rhino:

http://www.k2cnc.com/videos/GuitarProjectw...thCallouts.html

Bottomline: if I were to invest in just *ONE* software package, would Rhino be the one? ...that would allow me to model the guitar AND then bring the dwg file (and the wood) to a shop w a K2/Haas/Fadal?

Tonemonkey - most shops with decent software can handle just about any curve that you give them. Splines are a pretty basic drawing element for most CAD/CAM programs...I'm surprised to hear that they are giving you a hard time about that.

P90 - I'm in Maryland (I used to post under the name "TechArt", but I lost that login info!). A bit more on what TM was talking about...splines are 2D or 3D curves...if you were going to model a LP top, that would be done using surfaces (which are usually creating using a bunch of splines). Rhino is very capable of doing surfacing tasks like this...but surfacing is an art and it will probably not be a quick thing to learn.

I chose RhinoCAD & RhinoCAM as my software and couldn't be happier with it. I feel that it is by far the most competitive package out there.

I think the best way to get into CAD/CAM is to get into CAD first. You can only machine what you can draw...and even if you never grow to the point where you are ready to jump into CNC, CAD is an extremely useful design tool.

Here's a screenshot of a surface I setup to carve a carved back for an OM style acoustic that I have been working on occasionally (it's basically an archtop-type surface):

Here's a pic of the actual part, carved with that surface from Black Walnut..the outline is a bit rough because I bandsawed around the outside. After that, I glued it right to the kerfing and used the router to trim the back even with the sides (as you would normally do). I'm really happy with it, I think it's noticeably more comfortable than a regular acoustic back.

[GuitarEng]

I just saw the post about Solid Edge. I think that in the mid-level 3D CAD market - this means Solid Edge, Solid Works, and Inventor - SolidWorks is the best...and the other 2 are trailing. We use SW at work and it's a great package.

I gotta get my jabs in for Rhino though...Rhino does some surface stuff that SW just doesn't do. SW is a much more well rounded package, but Rhino is a fraction of the cost...

[Reaper]

I just saw the post about Solid Edge. I think that in the mid-level 3D CAD market - this means Solid Edge, Solid Works, and Inventor - SolidWorks is the best...and the other 2 are trailing. We use SW at work and it's a great package.

I gotta get my jabs in for Rhino though...Rhino does some surface stuff that SW just doesn't do. SW is a much more well rounded package, but Rhino is a fraction of the cost...

I don't know SW, so I'll defer to your judgment and experience on that.

In my experience, Inventor (which I used for three years of highschool), absolutely blows SE out of the water from an ease-of-use perspective. And FWIW, I know that I'm not alone on either of my opinions regarding SE and Inventor.

Punchline: use what makes you happy. While I can't speak for all programs out there, I would advise you to stay away from solid edge. And there lies my two cents.

[thegarehanman]

I love solidworks. It's very user friendly and like stated earlier, very well rounded. Like in any other program though, creating well knitted surfaces in it is a bit of an art.

[P90]

Another CAD software question - what grid dimensions are most commonly worked in?

For instance, fret slots are usually done in 100th's (IE: 6.397" for the 5th fret on a 25.5" scale) whereas the most common nut width is 1 11/16" which would imply working in 1/16ths or 1/32nds (1 11/16" converts to 1.6875").

So is 1/100ths or 1/32nds for the grid?

[GuitarEng]

The grid itself is inconsequential......when I'm laying out a part to show fret slots, or something like that, I'll draw the nut line and then use the offset command and then trim the slot lines to the edges of the neck. Most CAD systems allow you to enter coordinates/measurements so that you don't have to "eyeball" everything using grid & snap options. That would be a truly painful way to draw..!

Whatever software you buy should come with tutorials & a manual...if you are new to the software you could probably get a lot of mileage out of reading through that stuff.

Another CAD software question - what grid dimensions are most commonly worked in?

For instance, fret slots are usually done in 100th's (IE: 6.397" for the 5th fret on a 25.5" scale) whereas the most common nut width is 1 11/16" which would imply working in 1/16ths or 1/32nds (1 11/16" converts to 1.6875").

So is 1/100ths or 1/32nds for the grid?

[davee5]

Here's my experience, but note that with all of these programs if you're not stealing it, they're not cheap.

- SolidEdge: Cheap for schools so it was ubiquitous for a while. OK interface, crashes too easily, hard to get complex parts down easily.

- SolidWorks: Most user-friendly CAD package. Very powerful once you learn how to use it. Decent surfacing capabilities, not great for parametric based models if you need mathematical flexibility. This is my usual go-to. Built in FEA tools, decent drawing tool, and assemblies that can easily handle moving parts are all very nice and accessible features. Probably also has the easiest learning curve of most CAD packages.

- AutoDesk Inventor: CRAP. Sorry, but I hated it. Cheap, and more like a kid's drawing tool with it's snap-to-grid setup. Renders very well, but the drawing, modeling, and analysis tools are all very underpowered and not very versatile. The fastener library, though, is very nice.

- PRO/Engineer: Depends on what you're using. Wildfire is slick and tries very hard to keep the raw power of PRO/E while gainig a SW-like interface. Older versions are terrible from a UI perspective, but this is a very capable program. Very difficult to do surfacing work, but the parametric kernel makes for a very flexible model once you learn to set it up well.

- UniGraphics: Powerful tool, horrible interface. Unix based versions are the most common and the hardest to use to boot. I know some people who love this and can do great thigns with it, but these are invariably people whohave not used other packages much.

- Rhino: limited experience with this, but it seems to be more of a 3D modeler's program for making pretty swoopy surfaces than making precision engineered parts. There is a definite market for this, though, and guitars may overlap Rhino better than SW. That said, only real serious CAD monkeys can make SolidWorks do the surfaces that Rhino lets even rookies pull-off, so if you want to setup some surfacing for carvetops this is the easiest way to start.

- Cattia: heavily used in automotive, so it must have the chops. Only used it for a few hours, didn't feel super-simple to me, but half a day is not a reasonable amount of time for an evaluation.

As for grids, don't ever use grids for final layout so forget you even asked. You absolutely MUST use dimensions and constraints to fully define your parts if you want to have any kind of accuracy in the final product. That means if you use the grid for a quick layout immediately afterwards you use dimensions to set the actual down-to-the-thousandths spacing of your frets.

A quick note on CNC machine selection. Envelope will probably be the most relevant feature for you as accuracy and speed aren't nearly so critical in woodwork as they are in machining titanium and aluminum alloys for aerospace. HAAS and Fadal have a very strong presence in the job-shop market across the US, and seem to be in a lot of schools (excellent marketing) so many people are familiar with them, but widen your search and there are a significant number of VMC manufacturers to consider.

-Dave

[GuitarEng]

Hey Dave, cool site. I have a similar background & similar CAD experience (less UG & ProE). I have done a lot of CAD automation/Design Automation programming using VB, Delphi, and Lisp though - you can do some cool stuff if you get into that.

Very nice web layout as well, it has a great look to it.

I do have to take exception with your idea that Rhino is only good for making swoopy curvy things. It is especially good at this, but I feel it is as good as AutoCAD at the more mundane CAD tasks. With that said, it really doesn't compete at all with SE, SW, or Inventor as a solid modeler. Rhino simply calls watertight surfaces "solids". Yuck.

Here's my experience, but note that with all of these programs if you're not stealing it, they're not cheap.

- SolidEdge: Cheap for schools so it was ubiquitous for a while. OK interface, crashes too easily, hard to get complex parts down easily.

- SolidWorks: Most user-friendly CAD package. Very powerful once you learn how to use it. Decent surfacing capabilities, not great for parametric based models if you need mathematical flexibility. This is my usual go-to. Built in FEA tools, decent drawing tool, and assemblies that can easily handle moving parts are all very nice and accessible features. Probably also has the easiest learning curve of most CAD packages.

- AutoDesk Inventor: CRAP. Sorry, but I hated it. Cheap, and more like a kid's drawing tool with it's snap-to-grid setup. Renders very well, but the drawing, modeling, and analysis tools are all very underpowered and not very versatile. The fastener library, though, is very nice.

- PRO/Engineer: Depends on what you're using. Wildfire is slick and tries very hard to keep the raw power of PRO/E while gainig a SW-like interface. Older versions are terrible from a UI perspective, but this is a very capable program. Very difficult to do surfacing work, but the parametric kernel makes for a very flexible model once you learn to set it up well.

- UniGraphics: Powerful tool, horrible interface. Unix based versions are the most common and the hardest to use to boot. I know some people who love this and can do great thigns with it, but these are invariably people whohave not used other packages much.

- Rhino: limited experience with this, but it seems to be more of a 3D modeler's program for making pretty swoopy surfaces than making precision engineered parts. There is a definite market for this, though, and guitars may overlap Rhino better than SW. That said, only real serious CAD monkeys can make SolidWorks do the surfaces that Rhino lets even rookies pull-off, so if you want to setup some surfacing for carvetops this is the easiest way to start.

- Cattia: heavily used in automotive, so it must have the chops. Only used it for a few hours, didn't feel super-simple to me, but half a day is not a reasonable amount of time for an evaluation.

As for grids, don't ever use grids for final layout so forget you even asked. You absolutely MUST use dimensions and constraints to fully define your parts if you want to have any kind of accuracy in the final product. That means if you use the grid for a quick layout immediately afterwards you use dimensions to set the actual down-to-the-thousandths spacing of your frets.

A quick note on CNC machine selection. Envelope will probably be the most relevant feature for you as accuracy and speed aren't nearly so critical in woodwork as they are in machining titanium and aluminum alloys for aerospace. HAAS and Fadal have a very strong presence in the job-shop market across the US, and seem to be in a lot of schools (excellent marketing) so many people are familiar with them, but widen your search and there are a significant number of VMC manufacturers to consider.

-Dave

[P90]

I'm curious how one would do a Strat with a carved top (like an LP) on CNC. There are 3 things going on the top-side: the carved top, the perimeter edge rounding, and the forearm contour.

Would each be done in separate passes?

If so, I guess the carved top comes first, but which is done next? Rounding the perimiter edges and then the forearm contour? (or the forearm contour, then the rounded edges?)

[P90]

Just to give this a bump update. I was able to find a dirt-cheap v3.0 of Rhino on Ebay, and I've got the 2D shape down using polylines, no problem. All x and y axis so far.

Now where to even begin to shape a carved top onto the 2D outline I've got so far?

I can use Surface | Extrude curve | Straight to bring it into the z axis and give it thickness, but that's not really a carved top.

How to start to create something like the carved back in post #11? (obviously Rhino) What menu items?

[GuitarEng]

Cool, congrats on picking up a seat of Rhino.

I also have Rhino 3.0...

I'll reply first to your 2nd to last post: Once you have done all the surfacing, you program the CNC so that it cuts the whole thing all at once. You don't cut the arm carve, then the binding, then the rest...you cut it all at once using either a spiral toolpath or a simple back and forth toolpath (depending on the part and your CAM software).

With regard to how to model a carved top....I would recommend starting with a neck carve. Carved tops are definitely more difficult. In both cases, you will be using the following commands:

*surface from 2, 3, or 4 edges

*Lofts

*Surface from network curves

*Sweep 2 rail

*Patch surfaces

Each of these tools have their place. The general order of operations is to build a wireframe grid..and then to use those splines & curves to create your surfaces. Make sure when you do the grid that if you have two curves coming togethor, they are are tangent at a minimum...and preferrably curvature continuous.

I'd recommend reading the book and then doing a lot of playing...you will need to spend a good bit of time on this in order to get good at it. Good luck!

Just to give this a bump update. I was able to find a dirt-cheap v3.0 of Rhino on Ebay, and I've got the 2D shape down using polylines, no problem. All x and y axis so far.

Now where to even begin to shape a carved top onto the 2D outline I've got so far?

I can use Surface | Extrude curve | Straight to bring it into the z axis and give it thickness, but that's not really a carved top.

How to start to create something like the carved back in post #11? (obviously Rhino) What menu items?

[P90]

Thanks! So when building a wireframe grid, are you mainly starting with one curve, copying it to a nearby location, modifying it slightly, copy, modify, etc (using whatever top/front/right grid as necc) methodically until that wireframe is complete?

And what command did you mainly use in the pic in post #11 to surface the grid, networksrf? loft?