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I want to buy a CNC within the next few years. It seems to me I would start by learning to use CAD software then CAM and machine. I know very little about computers but have a good amount of experience with the mechanical end of CNC in a factory setting.
I am wondering if there is a good software to help with learning CAD basics. Thanks.
                                      

If you're doing 2D or 2.5D machining, I think any vector-based drawing program will give you most of the early instruction. If you can draw in vectors then doing up a CAD for a 2D shape or elevations is pretty quick in any commercial CAD software.

As for 3D, that's a whole different ball game. If you're serious about doing 3D parts (ie: want to do them well) then the programs I've found work best are Pro/Engineer and Rhino for modeling. OneCNC also looks like it has a nice modeler in it, although I haven't tried it.

OneCNC and Pro/E are hybrid CAD/CAM systems and they're both very heavy on your wallet. Rhino is much less expensive. For what it's worth, I find Rhino just as capable for making models as Pro/Engineer for most things and much faster in nearly all cases. Rhino files can be imported into every CAM software of worth, usually directly.

My advice, if you're looking at learning to do 3D, is to get Rhino, work your way through the training manuals (they're thick and very comprehensive), and make use of the free support on their newsgroup (it's beyond great). Do that and you're on your way.

There are some plugins for Rhino that do CAM, and they do a pretty decent job. They're called RhinoCAM and MadCAM. RhinoCAM is made by the Visual Mill people and is essentially Visual Mill lite. From looking at both, and reading the reviews, MadCAM seems like a better package. MadCAM (as such software goes) is also pretty inexpensive. ob.com usually has the best prices on Rhino and it's plugins.

One you've got the 3D down, toolpathing and machining (ie: fixturing) are a whole other bag of worms...

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Thanks for the information, I will start looking for a 2d tutorial program.
I have been reading about Shopbot but have noticed some other brands mentioned here. I am wondering is one brand vs. another more proprietary with hardware and software. Making it less open to choosing what tooling and software is used? Shopbot seems nice for a novice because it is sold as one package.Mike Fleck38865.7665162037

As a rule you'll never have to worry about using any software with any hardware. Every hardware company I've ever seen has either has posts for their proprietary controller in all the software or uses a stock controller with a post (like WinCNC, which many companies use as their controller)

Shopbots are alright depending on what you want to do with your CNC. Generally, I wouldn't want to run hardwood on them and you won't be running their software if you get into any 3D carving. The things they don't have which you get in a higher end system are precision and rigidity (so your parts might not be as reliably repeatable and high feeds really won't work as the vibration will lead to a poor finish).

Once you look at getting a spindle and a solid table the cost difference between a shopbot and a much better machine is really low. A shopbot compares really poorly against a Larken or a Precix for cost/value IMO.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I agree on Rhino, I've done standard cad work for a while but switching to 3D was a bigger jump than I thought. However Rhino is reasonably priced, has a good support base, technical support is free through email (I found an oddity in one of the commands and they were very knowledgeable about how to work around it). AND they offer reasonbly priced training classes, I'm doing one in seattle in July...

I have Rhino Cam but have not used it yet, I cannot stand their security model, they use a dongle so you can only run it on one computer at a time. If you remove the dongle while it's running you get an endless stream of warning boxes . Outside of that it seems fine.

Now Bob has me wondering if I made the right choice on getting my K2 CNC, I looked at shopbot a while ago and was not all that impressed. But I've never heard of Larken or Precix ....

-Paul-

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-Paul-

Patriot Guitars

Dongles are definitely not my thing, as well. It takes -no- effort to grab an illegal copy of RhinoCAM or about any popular engineering CAD/CAM software so alienating your customers with this sort of thing is unnecessary. I don't need that hanging out of the back of my laptop so I can run toolpaths.

As for the router, there are a -lot- of options on those K2s. From looking at their site for a couple minutes it looks like you can get everything from a strictly hobby level machine up to a welded machine with a Colombo ATC and servos from them. When looking at a CNC all you can really rely on is seeing the machine in action cutting your part, talking to customers, and doing your homework on components. Even things like ballscrews, which have become sort of the 'buzzword' for a lot of sub-industrial CNCs lately come in grades ranging from aerospace-precise to cast ballscrews that are less accurate than a halfway-good rack and pinion.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

K2 had good tolerances when I did my research and they where priced about the same as ShopBot all told (in fact a little cheaper), they were super helpful in getting me setup with the right machine (the KG-3925 model), with my setup I got upgraded X&Y ball screws (.001) tolerance and and upgraded 5" Z ball screws (.001) tolerance.

I also got the slotted top and the clamp setup for it, a dust hood and the collet for a porter cable router. I chose porter cable because I've always had good experiences with their machines. One of the techs there told me that in a small shop like mine I should really consider building a whole cage to surround the unit to keep the noise and dust down, still not sure about that.

I've got Rhino down fairly well, still struggle with it but at least I can do things now. I may have to do something about Rhino-cam, I need to spend some more time with it before I make a final decision.

The good news is the machine will be shipped out on the 19th, just in time for the shop to be ready to accept it.

Mike I wouldn't worry about the software, make sure you get the best machine you can for the money, I have yet to find one that can't read GCode. I got Rhino and Rhino Cam because it did everything I wanted and had great support.

Cheers

-Paul-

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-Paul-

Patriot Guitars

Yeah, it sounds like you've got the right basic setup. You can always upgrade to a spindle later without much fuss, but the basic table needs to be set up right. With a decent ballscrew system the table is probably more accurate than the router.

It's definitely in a different league than a shopbot so it sounds like you made a good choice. Their prices on smaller machines seem really good.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

So here is where my in-experience comes in, what is a spindle? and why is it better?

One of the issues with CNC when your starting out is just the overwhelming amount of technical information you need to absorb to get going, it's not for the light hearted. It's a simple process in theory, but in practice there's a lot you need to know to be successful.

Mike's original question about the software is one that I struggled with for weeks before I finally made my decision. K2 suggested that I get Rhino, but I didn't take their word I did my own research and found that a lot of companies are using it and the company has good word of mouth support. I have so far found it to be a really good package for doing 3D. The fact that their suggestions agreed with my findings raised my confidence in them even higher.

That reminds me Mike, you can download a fully working demo version of Rhino, it comes with some tutorials (the ones in the manual are better) but it's a great way to get a jump start on using it.

Cheers

-Paul-

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-Paul-

Patriot Guitars

Mike,

You can save a bundle on software if you or your spouse are either teacher, faculty, or students. My wife bought a copy of Rhino at academic pricing, around $150.00 new.

As for machines, I did a half a year of research. I ended up purchasing a used techno table with new hardware. K-2 looked very good as well.

Shop bot was another story. A good friend is using one in CA making electric Bass guitars. After a year + of use, he regretted it because of repeatability issues and problems with the spindle jumping and the depth of cut changing when a chip would get caught between the carraige wheels and the rail.

Good luck and enjoy the ride...

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Paul Bordeaux
http://www.bordeauxinlay.com

The important (well, the ones I can remember) differences between a spindle and a router:

The short story is that they're higher precision/durability and are made specifically for production machining. The specifics are:

-Spindles are -not- hand tools in any way, they're made for use in automated or at least fixed machines and are optimized as such.

-Spindles generally come in horsepower ratings from 3-10 on the sub/light-industrial type machines. Torque is optimal at some speed but they are accurately variable over a range. In general torque=max torque*rpm/max rpm so if you're going 1/2 speed on a 7HP spindle you get about 3HP of torque. You can get spindles geared differently (so they can be optimized for max torque at 10K, 20K, 30K etc)

-Spindles have better bearings in them which are meant to handle the extreme sideloads of machining, the bearings take a really long time to wear out even in production environments

-Spindles have next to no bit runout whereas a router often has quite a bit (excuse the pun). So they cut cleaner, leave a better finish, and wear out/break bits less. Micro-size bits (for inlay, engraving) are very likely to break in a router because the runout is a significant proportion of their diameter.

-Spindles are built for continuous use, so they won't be subject to thermal wear (overheating) during long machining.

There are also some fancier options available in spindles like automatic tool changers and quick change systems. The downside, of course, is in the price difference. A spindle is going to run you about 3K and things really start moving up (automatic toolchangers are about 10K)

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

As for Rhino: You can get Rhino and MadCAM both at educational pricing for <400 combined on ob.com. The Rhino license says that it's perfectly fine/legal to use Rhino bought on an education license for a business as long as only the purchaser is using it. I'm not sure about the MadCAM agreement but I would assume it's similar.

I'm in the fortunate situation of being a graduate student right now so this sort of thing's definitely helping me out. OneCNC also has a big student/educational discount and others probably do as well.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I have a customer who teaches Autocad and has offered to help me using Autocad. I have not seen Autocad metioned here. Is that because it is very expensive compared to other programs that will do the the work or is not a good program for guitar designing? Mike Fleck38869.1046875

It is very expensive, and extremely overpriced IMO, compared to the other solutions. It's adequate to do 2D design work but not 3D. Also, AutoCAD with 3D (not the 2D only version which is still expensive) costs more than most full 2D/3D CAD/CAM solutions out there!

I'm going to go out on a limb (well, not really) and say that the only reason AutoCAD is still around is because it became an industry standard and used some shifty tactics to quash competitors in earlier days.

So, in short, AC isn't what you're looking for and the only reason I'd ever willingly use it is if a company hired me specifically to use AC (if they just wanted AutoCAD files then I'd do them in a different program and export them). That being said, I do know how to use it pretty well and have designed some guitars in it but it is -not- in any way worth it, I'd only consider it for 2D if it were free and I'd never consider it for 3D.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

To begin with, I don't use cad constantly in my job. I started out with a Mac and MacDraft a long time ago. Then we switched to PC's and started to use AutoCad. I found the transition difficult, as MacDraft was a simple program to use. I eventually got to a point where I could work with ACad pretty well. Then we switched to Acad LT. which is a more modern 2d version. This has worked out well for me. At home I have Bobcad V17 and V20 which I purchased recently. The CAD capabilities in Bobcad drive me nuts, because they aren't like ACAD at all. I now draw in ACad and create the Gcode in Bobcad. That works out pretty well.