Official Luthiers Forum!
http://mowrystrings.luthiersforum.com/forum/

Getting into CNC, suggestions appreciated
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10106&t=41865		 Page 1 of 2
Author:  Kelby [ Tue Nov 05, 2013 5:17 pm ]
Post subject:  Getting into CNC, suggestions appreciated
I'm thinking about taking the plunge into CNC. I'm building archtops these days, and I would use it for inlay, fingerboards, rough carving plates/f-holes, etc., and I might make some signs on the side.

Laguna is running a special on their IQ HHC. Does anyone have experience with this machine or have suggestions? I like the fact that it comes with a 3HP water cooled spindle, as that presumably helps keep the noise down. I would like a turnkey system.

As for software, it sounds like Rhino and Aspire are popular, and that Aspire has less of a learning curve. I would appreciate thoughts and suggestions on the software side as well.

Thanks.
Author:  Andy Birko [ Tue Nov 05, 2013 5:45 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
I don't have any direct experience with Aspire but I don't think it's going to do what you're looking for in terms of arch tops. Aspire is more of a 3D art type of package where you can import 3D relief type of stuff. It will do a great job with inlay though. Again, with no direct experience I'm only guessing but, you probably could have someone make your archtop model and import it into Aspire to create toolpaths etc.

Aspire is fantastic for inlay and 2D work though. I use Vcarve Pro for inlay and other simple 2D work and its tools for messing with vectors are really top notch. Vcarve is like Aspire light.
Author:  Andy Birko [ Tue Nov 05, 2013 5:47 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Oh, and the common recommendation is to download demo versions of the CAD/CAM software and see if you can draw your parts. Modeling an arch top is not trivial to get it the way you want it. If you can't draw your parts in CAD, you can't get the machine to make them.
Author:  ballbanjos [ Tue Nov 05, 2013 6:46 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
I don't know anything about the Laguna machine, but like Andy I use VCarve Pro for 2D stuff--for inlays, flat fingerboards and all kinds of other stuff (including signs), it's a great tool. I use Rhino/MadCAM for doing archtop plates, necks, radiused fingerboards and other 3D stuff. But there's definitely a longer learning curve doing 3D than 2D.

I got some videos on modeling archtop plates using Rhino that were very helpful. I got mine from luthiertool.com, since they were Rhino centric. Neither necks nor archtop plates are super-easy to model in CAD, but with practice it's not bad.

I guess that the bottom line for me on CAD/CNC is that it's a great tool, but just like with hand building it takes practice and experience to develop the skills needed to make it worthwhile. A lot of folks look at CNC and think of it in terms of putting in wood and getting out guitars. Once you have your models and toolpaths tweaked and working, that is somewhat true. But, the work that goes into building those models and toolpaths isn't insignificant. I can definitely build an instrument completely by hand much quicker than I can build the first one using CAD and CNC. It's the ones after the first one where you can start to see some return on investment.

My personal approach with CNC is that I use it where I previously used a shaper or a router--I use it for roughing things out (although I do have to admit that the rough out is pretty close to ready to sand and finish). But it doesn't replace the things I've always done by hand. I still like to do all of the final carving on everything by hand. I still like to do any fancy carving there might be to do by hand, and still do all of my engraving by hand (as well as much of my inlay work). That's the stuff that really differentiates the small shop handmade instruments from the mass produced, and even though CNC certainly can give you the potential to mass produce (and through the CAD process gives plenty of creative opportunity as well), it can also be used as a modern replacement for machine assistance that many of us have used on handmade instruments for years. Oh yeah--it also keeps your fingers far from sometimes scary shaper cutters! There's fun and creative satisfaction to be found in the CAD/CNC side, but I still have a personal need to do lots of hand work--I just prefer it to be the finer level stuff instead of the hogging off material stuff.

Dave
Author:  Kelby [ Tue Nov 05, 2013 7:08 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Andy and Dave, thank you!

I appreciate that it's going to take me some time to get my modeling skills and files in order, and that I'll keep building the old fashioned way while I figure the CAD/CNC side of it out. Dave, I also appreciate what you're saying about continuing to do the fine carving by hand. I do see CNC as primarily the way to get things roughed in. With that said, it will clearly open some doors on the inlay side. My eyes just aren't good enough to route those cavities as precisely as I once could!

I was leaning toward Rhino, and based on your comments, that's probably the direction I'll go.

As for the machine, I understand that you can't speak to the Laguna, but tell me this: Do you use a tool changer? If not, how much do you miss it? If so, has it made much of a difference? I don't believe you can mount an ATC to the Laguna, so I would have to go with something like the Stinger if I wanted to upgrade to an ATC down the road. But the pricing on the Stinger is quite a bit higher, especially after an upgrade to a substantial spindle, so I would prefer to invest smaller for now unless something like the ATC is likely to be extremely valuable to me.
Author:  ballbanjos [ Tue Nov 05, 2013 8:12 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
I don't use a tool changer, and actually for the volume of work that I'll ever be doing with the CNC I don't feel any need for one. If I was really ripping out huge numbers of instruments, it might be different. But given that my whole thing goes back to the handwork and basically doing one instrument at a time, cutting out maybe 15 minutes or less of time from my overall time to build is completely insignificant. If you're Martin or Taylor or some big time production company like those, yeah a tool changer would make a big difference. Even if you're producing single parts in quantity, it would be a big deal. But if you're a small shop turning out a small number of instruments I think a tool changer would be an unnecessary luxury....

Dave
Author:  Kelby [ Tue Nov 05, 2013 8:36 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Thanks, Dave! That's what I suspected, but I would have hated to invest in a system and then learned that I was missing something important.
Author:  RandK [ Tue Nov 05, 2013 10:18 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
I've not seen a Laguna but it's a Chinese machine perhaps with some custom specs. I wouldn't buy one without getting some basic specs like repeatability (or accuracy), speeds and feeds, motor/drive specs and a manual. Some of the Chinese HHC's are metric only, they don't do basic things like use the feed rates in the G-code and of course are Chinglish. I think I would invest in a cheap flight to look at them first. I'd want to know what kind of support you get from them or if you are ever going to be waiting for parts or help from China.

Others in this class are the Camaster Stinger (also on sale), maybe the K2CNC, and the Shopsabre R&P drive machines but they are all going to be more than $5500 but will have better specs.
Author:  Kelby [ Wed Nov 06, 2013 12:39 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Thanks, Rand! Those are good questions, and I've got some of the info, but I'll get the rest. One more question: when you say that some HHC's are metric only, does that mean that I have to do my CAD work in metric? That won't work at all!
Author:  ballbanjos [ Wed Nov 06, 2013 6:09 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Here's a link that goes into some of the apparent issues with the Laguna, including the metric only issue:

http://www.sawmillcreek.org/showthread.php?193856-Initial-Laguna-IQ-HHC-Review
Author:  RandK [ Wed Nov 06, 2013 9:40 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
That review was a little ugly but it seems like it is working OK. I was wrong about the feed rates from G-code. Spindle speed via g-code is something I live without but definitely nice to have. It sounds like metric only on the HHC but that's a big one to find out if it requires metric posting of the g-code. I don't think I'd want to design in imperial units and do cam in metric -- too prone for errors. That review was from a year ago so maybe the product has improved. Get and check references, preferably a luthier.
Author:  Kelby [ Wed Nov 06, 2013 11:46 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Thanks, guys. I had seen that review. Some of the info in it is inconsistent with what Laguna is telling me -- for example, Laguna has verified that the machine does allow spindle speed control via g-code. I'm not sure who is mistaken on that issue, but I'll keep digging into it. The metric thing concerns me, and I'll get some info on that as well.
Author:  Kevin Waldron [ Wed Nov 06, 2013 12:01 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kelby,

We have a little different take than Dave...... we wouldn't consider a machine without tool changer.

Take something as simple as a fret board ....takes at least two tools.... better probably with three tools..... One to surface the board, One to cut the slots , and One to cut the board to your size requirements. If your going to be doing necks...... a ball nose tool will cut the basic neck but it want cut the peghead, and probably not the truss slot. If your going to be cutting body molds..... we use a V-tool to mark various lines and text, we use a drill for location holes, sometimes we have to use two size end mills. If your going to be cutting archtop plates you will need at least one ball nose mill and probably two, small end mill for the f-holes, end mill for plate cut out and possibly a drill tool.

This is just my two cents.

Blessings,

Kevin
Author:  Kelby [ Wed Nov 06, 2013 12:46 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kevin, those are very helpful thoughts. I'm also going to look at some machines that would offer an easy upgrade to a tool changer down the road.
Author:  ballbanjos [ Wed Nov 06, 2013 1:14 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kevin is definitely right in what he says regarding the various tools needed. My cheapo alternative has been to run half a dozen or more similar pieces in a batch. First I'll run all of the pieces using the first tool, then I run them again using the second tool, etc. Everything is indexed, so it's quick and easy to change out work pieces. I don't have to re-zero in between pieces (only between tools), etc.

On things like banjo fingerboards, I can run a bunch of fingerboards to a certain stage--say, surfaced, slotted and profiled--and then store them until I'm about to use them. This would involve 3 tools on 3 separate runs on a bunch of indexed fingerboards. Then, depending on the order, I'd re-mount the board to cut inlay pockets to order, scoop the fingerboard if desired, etc. For doing things this way, the tool changer wouldn't really buy me anything, but if your production involves doing one piece (or group of pieces if the machine is big enough--mine isn't) from start to finish, then doing the next piece, a tool changer would undoubtedly help.

Just a couple of different ways of getting to the same end point.

Dave
Author:  Andy Birko [ Wed Nov 06, 2013 2:14 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kelby wrote:
Kevin, those are very helpful thoughts. I'm also going to look at some machines that would offer an easy upgrade to a tool changer down the road.


I'm not sure there's such a thing as an "easy" upgrade to an ATC unfortunately. ATC's run anywhere from about $3 to $10k depending on what you're looking for.

I've been recommending this for ages now but my buddy Ger has a screenset for Mach 3 that makes manual tool changes very painless: http://home.comcast.net/~cncwoodworker/2010.html

Although you still have to be around to change tools, it's simply a matter of putting the tool in the collet, pressing cycle start and walking away. This is about as painless as it gets for manual tool changes.
Author:  Kelby [ Wed Nov 06, 2013 4:32 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Thanks, guys!

I've gotten some more information from Laguna -- (1) repeatability and positioning is +/- .002, (2) they confirmed again that HHC controller can control both feed rate and spindle speed through G-Code (either in the software or as raw G-Code), and (3) HHC is metric only.

Should the last item concern me? I build guitars in inches, not centimeters. Laguna tells me that I can design in inches, and the post-processor will translate it to metric for the machine. Is it as simple as they're making it sound? Suppose I use Rhino plus RhinoCAM, and I design an arched plate in inches using Rhino and then set the toolpaths in RhinoCAM. Where exactly does the file get converted into metric, and will it require any effort on my part? Sorry for being so clueless about all of this. Unfortunately, I think a lot of this will make more sense to me once I start using CNC, but I can't start using it until I have it, and I can't have it until it makes more sense to me, and so on . . . .
Author:  ballbanjos [ Wed Nov 06, 2013 5:36 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kelby wrote:
Suppose I use Rhino plus RhinoCAM, and I design an arched plate in inches using Rhino and then set the toolpaths in RhinoCAM. Where exactly does the file get converted into metric, and will it require any effort on my part?


When you create a new file in Rhino, you specify whether it is measured in metric or inches. Anything you design will be in whichever measurement system you chose. When it comes to the CAM side of things, I use MadCAM but I assume RhinoCAM is the same way--it follows the CAD model, and when you choose a post processor to output the G Code, you select either millimeters or inches--there are different post processors that you use to match whatever your Rhino drawing was using. It's no big deal at all--no conversion involved, at least on my machine using Gecko drives and Mach3.

<EDIT>

I hadn't looked at how the HHC works on the Laguna. Looks to me like that might be of some concern if it's metric only. With Mach3, it's not an issue. I've never tried to use a metric post processor as a converter from inches to millimeters. Guess I spoke up too soon! Sorry 'bout that.

</EDIT>

My CNC machine is all metric (metric ball screws, etc.), but I work in inches. It's completely transparent.

Dave
Author:  Kelby [ Wed Nov 06, 2013 8:50 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Dave, thanks, although I have to confess that the Edit tags on your post confuse me as to what part was the original thinking, and what part came last. Do you mean to suggest that you thought it would be OK, but then realized maybe it will be a problem? Or the other way around?
Author:  turmite [ Thu Nov 07, 2013 3:24 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Guys maybe I am reading this wrong, but if the Laguna machine is what he wants, would it be simplest to model the parts in Rhino in inches, then just let Rhino do the math to convert it to mm. Then use Madcam :mrgreen: to cam the model in mm and your problem is solved.

On the other hand, if I were looking, I would be looking another direction than a Chinese built machine that is dedicated to mm!

Mike
Author:  ballbanjos [ Thu Nov 07, 2013 6:06 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Sorry for the confusion--I was obviously the most confused! I think Turmite nailed it though--I hadn't realized that the Laguna machine ran off of the dedicated HHC--I was still thinking Mach, where it would be no issue.....

Dave
Author:  Kelby [ Thu Nov 07, 2013 10:42 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Thanks. Dave and Mike!

I'm definitely looking at other options as well. Laguna's price is hard to beat, and they are local, and they have been pretty responsive with me. (Getting a quote out of some of the other manufacturers has been a challenge!) But the Laguna machine also has some limitations. I'll see where (and whether) the other quotes come in.
Author:  David Malicky [ Thu Nov 07, 2013 9:13 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Kelby wrote:
I'm definitely looking at other options as well. Laguna's price is hard to beat, and they are local, and they have been pretty responsive with me. (Getting a quote out of some of the other manufacturers has been a challenge!) But the Laguna machine also has some limitations. I'll see where (and whether) the other quotes come in.

Historically, Laguna has had very responsive sales staff and unresponsive service. Maybe that's different now--I don't know.
Velox http://www.veloxcnc.com/ makes similar machines as the Laguna. I think they are a spin-off from K2, which has a reasonably good service reputation.
I would investigate whether the Laguna, Velox, or another machine is good enough to do fine inlay. 0.002" repeatability is rather high, but probably typical in the <$5k price range for this size machine. Cutting the size down to 2'x2' or less may help.
I wouldn't let the spindle drive the machine decision -- those are easy to replace, and you'll probably want an air spindle for inlay.
We have a K2 3925G without a tool changer, and use the same method as Dave when making parts that need multiple tools.
Author:  npalen [ Thu Nov 07, 2013 11:08 pm ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Something to keep in mind if you are concerned about the learning curve associated with 3D CAD: Hand carved parts such as the arched plates can be digitized on the CNC machine and reproduced in Gcode format. Digitizing does take time but it only needs to be done once and there is something to be said for reproducing hand carved work, with its irregularities, rather than computer generated shapes. I've done it both ways and either one works.
Author:  Kelby [ Fri Nov 08, 2013 1:08 am ]
Post subject:  Re: Getting into CNC, suggestions appreciated
Very helpful advice, guys!

David, I've had several Laguna tools, and they've treated me well both before and after sale. I'm not worried about that part of it.

The Velox machine is nice.

On the repeatabiliy issue, does .002 sound too high for inlay? I have to confess that, for my hand-cut inlay, I would love that kind of accuracy! I note that the spec for your K2 is .001, although it's not clear what router/spindle that spec is for. Do you think the difference between .002 and .001 is enough to be a concern? .002 sounds pretty good to me, but I have no experience with all of this.

Thanks again!
Page 1 of 2 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/