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Hi All,

I'm going to get my hands on a small CNC machine soon, so I'm trying to get up to speed. I'm new to CNC, but I was a software developer for many years so I'm not entirely non-technical. ;->

At present I'm doing custom inlay on guitars for a local guitar builder, so once I get the machine up and running I'd like to cut some inlays from shell, wood, metal and other materials and rout the cavities. I do have many years of 3D modelling experience but only on Lightwave3D. I know how to make purdy near-photorealistic (and mostly useless) images.

Since I haven't even seen the machine yet, I'm concentrating on understanding the general software requirements.

I know I need some sort of CAD package to make my models for 3D stuff. Maybe I can convert Lightwave output, but I'd eventually like to move to something like Rhino. Though perhaps there's a way to use DXF's exported out of Adobe Illustrator for 2D things like inlays?

I have no idea what to get for a CAM program or machine controller. Does anyone have any suggestions for software to get up and running doing inlays? I'll save the 3D stuff for later. Though I guess a radiused fretboard cavity is actually 3D.

I'd also love to hear anyone's experiences cutting inlays, particularly dealing with shell.

Thanks,
Athena

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For doing inlay on fretboards, there are a number of packages that can do that - certainly Rhino or Solidworks on the modeling side - but these packages are very expensive -

If you go the Solidworks path, you would be well advised to pick up the videos that CyborgCNC has on his site. He walks you through the inlay process step by step, both designing in Solidworks, and also machining with Mastercam...

Another, less expensive, option is VCarve Pro, with Cut3D. You can check these out, along with a gallery of what folks have done with them, on http://www.vectric.com

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Mitch

Checked out your website Athena, and that is some amazing work there. Have you displayed at Healdsburg before? I saw some beautiful inlayed banjos there that looked like yours.

As far as doing 2d inlays, even Vectrics lowend Cut2D will do this with some manipulation. Using your Dxf files and importing them. This will allow you to make the intricate drawings which Cut2D cannot do. as far as manipulating the cuts. You more or less use the pocketing toolpath for the cutout and outside profile toolpath for the inlay. Where you make changes is in your tools.

What that means is to trick the software to make tool compensation in diameter. If I use a 1/8" endmill for the pocket. It's diameter is 0.125, now for the inlay profile I will set the tool diameter for 0.122, while still using the 0.125 endmill for the cut, The software will compensate for the 0.122 and the toolpath will be for that diameter to cut the profile. This makes the 0.125 bit take off 0.003 more material. I always test the fit and make adjustments to this as different materials seem to make this change by 0.001 +/-

As far as controller software, Mach3 is what most people use. There is also EMC2 which is freeware and runs on Linux. As well as Quantum which is a freeware of Mach3 so to speak. It was a Beta version that was never released but it does work well.

As you can see there are many ways to get where you want to go. some just require a different mindset.

Mike

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I'm outside looking in, just farther from the window than most.

I've been talking to the builder about Rhino for a long time. Telling him to expect the financial hit should he go CNC because I wasn't going to make CAD models in Lightwave. I think his son is the most excited about it. He's about to take shop class this year and is already asking for the educational version as a birthday present. Hopefully I'll get to check it out and make sure it feels good to me. Then I'll be confident enough to insist that this is what we must buy and that it's something we won't outgrow.

If he takes his version and disappears into youthful geek heaven, then there's always the demo version. I'll have to focus on evaluating it within the 30 days. Not horrible but I'll probably have to do that with CAM and machine software too.

I'll check out the Vectrix stuff. Solidworks I know is out of price range for now.

Thanks,
...Ath

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No, I've never been to Healdsburg. In fact I was really bummed about missing it this year, but I had just moved to Calfornia and had no spare time to deal with it. You're thinking of the great Renee Karnes

http://www.banjosbyrenee.com/

I'm honored to be confused with her but I'm relatively new at this and she's of the greats.

Thanks for the compliment though!
...Ath

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I have heard Mach3 mentioned a lot over the years and suspected it was what most people used, but my last research was a while ago. Good to know there's some freeware though as it might be a good idea to see if this thing will do anything useful first before investing in software.

Thanks SO much for the bit about tricking the software! That makes sense. I read something yesterday on the CNCZone that concerned me:

" I am trying to use Mach3 to do inlay. I imported a dxf file into lazycam and was able to generate code to cut the outline of the object, but cant figure out how to generate the code to pocket cut the material in the middle of the object where the inlay piece will go. Will Mach3 / Lazy cam do this?

No, but I think the soon to be released Pro version might. You might want to look at http://www.sheetcam.com"

If you can cut an inlay piece, why can't you cut the pocket or at least fool it into doing so? I do this by hand already. I even design a small offset into my routing patterns already. I know I have to watch the radius of my end mill with respect to the tightest inside curve. The web is cornucopia of information - some of it might only lead me down the garden path and it's hard to tell ahead of time.

Though I can't remember the last time I used a 1/8". I end up doing very small/fine things. I've already scoped out the PreciseBits website. They have some info on cutting shell, feeds and speeds,etc. And, thankfully, how to help with runout on routers. I like their idea of precision collets. I've read it's best to have some fancy high speed spindle for shell cutting, but that's not going to happen right away. If this thing has a Dremel, it goes in the trash. I know lots of people do wonderful things with them, but I'm not a Dremel grrl. I'll look into getting a small router/laminate trimmer and the new collet. The builder might even have a spare one I can use.

Thanks again for your help!
...Ath

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I understand about the 1/8", the same applies to smaller cutters as well. Just was an example. As far as your concern about M3 and Lazycam. Mach3 is the controller software. Lazycam is a freeware Cam program and has it's limitations. So the Mach3 will work with MANY Cam programs,as well as manual Gcode input, or Gcode typed in Notepad and saved as a txt file, so this should not be a concern . Most of the problems I see with M3 is setup problems for people. The most common problem is toolpath interpretation is in arcs or circles and not setting the config on M3 to allow incremental IJK mode.

Hope this helps.

Mike

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I'm outside looking in, just farther from the window than most.

Yes, it does help! It was unclear from this person's post and the answer. It sounded like he was saying Mach3 couldn't do it which really confused me! Though one would think that Lazycam could be cajoled into it, but perhaps I'm missing some key point that's different about routing pockets vs. cutting inlays?

I was also hoping to use the thing to radius fretboards (if it turns out to be wide enough), cut slots and even mill my stock down to thickness.

>or Gcode typed in Notepad and saved as a txt file

That IS going to happen...LOL. I'm an old assembler programmer who gets very frustrated when high level software won't do what I want it to. I should download a good Gcode reference right away.

Thanks!
...Ath

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First off: VERY impressive work. I don't think I can say that any more clearly. The artwork is done beautifully, material selection is spot on, and your pockets are some of the nicest I've seen done by hand!

Mach3's job is just to tell motors to move X turns left or X turns right, then tell you where it thinks it told the CNC to go, nothing more. Any limitations on the sort of machine motion that can be generated are a function of your CAM software, which decides what turns Mach tells the motors to make

G-Code is a very simple interpreted language, it's little more than a list of X,Y,Z coordinates for the machine to move through with some simple machine functions (spindle on off, coolant on off, etc), a couple methods of motion (arc, linear, helical), and occasionally some macro or transformation ability (eg: scaling the part up, loops, gotos, cutter compensation, etc). If you can think in 3D then G-Code will be second nature in no time.

I started out in 3D with Lightwave 4 or 5, I forget which, many years ago. A lot of the functions of mesh modelers carry over to NURBS modelers (extrusions, booleans, scaling, and all that), but it is a paradigm shift in that meshes can be manipulated much more directly without creating 'kinks' or 'cracks' in the surface. For non-parametric 2D work and fully 3D NURBS surfacing, Rhino has no peers, but it does cost most of a thousand dollars and the better part of users will never use half the power it has under the hood. For parametric 3D work, Solidworks is definitely the reigning champ, but if you don't need parametrics then it's a big price jump! I can't recommend a 'lowest-end' 2D modeler that I believe is adequate, but for combined 2D and 3D work the best bang for your buck is Moi3D at $200. It is fully file-format compatible with Rhino, has a large subset of the functionality, and is actually coded by the guy who originally coded Rhino for McNeel.

Inlays are one solid contour, run at various depths. Cutting a pocket requires the software to offset the cutter from the outside cut multiple times, making sure these overlap, so that it can hollow out the entire area of the pocket. So one requires just following a line, while the other requires generating paths algorithmically.

Using the CNC to mill stock to thickness is quite nice as you can jog it down in tiny increments and, if your stock is firmly supported, you can be sure the cut surface is more or less dead flat. If you understand arcs in G-code then you can manually code a program to cut radii and slots pretty easily, and it's nice to be able to cut blind slots to hide those fret ends!

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Thanks so much for the compliments! It means a lot especially coming from you. Yeah, I've lurked here a bit and already checked out your website. That piece on your front page (and your avatar) totally blew my mind when I first saw it.

It's cool to hear you started in Lightwave too. I got a plugin to output .stl files for it but I have no idea if it actually works.
I've being eyeing Rhino for a while and hearing great things about it. I barely understand parametrics so I'm guessing they won't be a big help to me. Interesting about Moi3D. I've never heard of it. I'll have to check that out in detail.


Wow. And I thought I'd have to program the toolpath to do what I do manually - run around the perimeter then hog out the inside. I didn't expect anything to be generated algorithmically.

Thanks SO much for all the great info!

...Ath

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Wow - that is some nice inlay work! With an eye for design like you have + CNC, it will be really interesting to see what you come up with next...keep us posted!

I don't have experience with Moi3D, but I'm sure that if Bob says it is good, then it is..

I use Rhino and RhinoCAM with my K2 CNC and couldn't be more pleased with this system. There is really no need to use SolidWorks or MasterCAM, especially for inlay. I think Rhino is a better tool than SolidWorks for inlay design...it's a bit more artistically inclined than SW.

Trev

edit: here's a link to a couple of screenshots showing some CAD work for a marlin inlay that I did awhile ago:
viewtopic.php?f=10106&t=24906&p=336924&hilit=marlin#p336924

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+1 for MoI3D and "thanks" to Bob for the original recommendation. I've spent some time with Rhino and honestly there's something about the interface that literally gives me a headache if I work with it for more than an hour. Now I just use it to analyze models that I made in MoI. Rhino will give you a free demo (your choice of something like 1 month unlimited use or ~25 saved files). If you choose the saved files version you can use features in it indefinitely - you just have to be judicious with what you save. I use Aspire Cut 2D and Cut 3D Cam programs which are available in a Shopbot package. They're very good, but don't have the flexibility of the more expensive Cam programs. One trick I've learned is to model inlays and pockets separately in MoI then have the Cam program convert both models into G code. Cam programs will allow you to shrink or enlarge a model (to create a slightly larger pocket), but I've found I get much better results with two separate models. Oh - and like has been said before, beautiful inlay work and I can't wait to see what you do with a cnc machine.

Bob

Thanks Trev!

I already checked out that thread when it was first posted and saved your feed, speed and tooling info in my CNC notes file. Cool Marlin! Being Maryland-born your past work history did not go unnoticed. I still have a Cu24 20th Anni I haven't been able to part with.

Great to hear another vote for Rhino. I'm still SO up in the air about the CAM side of things. There are so many options from freeware to megapayware with people loving and hating them all.

...Ath

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Thanks!

I do need to check out the Rhino demo. Though I fear I may have downloaded it a year or two ago and just never got around to playing with it due to one crisis or another. I wonder if they'll let me have another.

I know what you mean about the interfaces. I'm a long time Lightwaver and I tried to use 3DS one day and couldn't deal with it. It was awful, alien, non-sensical. It was a LONG time ago and Max is much better, I hear. But I should find out if Rhino makes me break out in hives...LOL. MoI3D might be a better option for someone has spent quite a bit of time as a user interface designer.

I kind of imagined doing separate inlay and pocket models... probably just because I don't trust high level stuff. ;-> It's good to hear someone actually does that.

...Ath

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Well the machine is here in the woodshop next door and it turns out not to be a small CNC router but indeed, a mill. It's a Taig Micro Mill, which does have a very good rep for what it is. According to Taig Tools it's not their controller box, so perhaps it was DIY CNC job.

Pics here: http://home.comcast.net/~ath3na/Taig.html

I'm curious if anyone here uses a similar machine for any lutherial tasks or knows anyone who does? Bob, sorry you don't really count because your mill is so darned big (and cool and powerful and boy I'd love to have one but could never afford even the support). ;-> Though while the limitations of a small mill may not apply - the issue of using a metalhead device for wood certainly does, so I'd love to hear your thoughts anyway.

It appears the X travel is either 9.5" or 12" which is not long enough to rout a set of fretmarkers. It'll be ok for headplates, 12th fret inlays and other smaller items I guess. It should be able to cut inlays but I'm concerned about the slow r's: Either 5k or 10k max rpm. It was good seeing Trev cutting shell with 25k and not the 60k I've heard recommended.

But this is a metal mill, and I know that metal cutting speeds are usually slower. I know even the band saws run slower. I hear wood wants high rpms and shell even higher. I don't know about you guys, but I feel like I don't actually "cut" the shell, I merely grind it away...LOL. It has zero malleability. Metal, on the other hand, I charge right through. Those jeweler's blades were designed originally to cut metal, after all.

I guess we could possibly prototype an aluminum bridge on it. The builder might do a one-off 7 string version of his bridge he wouldn't want to order in bulk, like the others. I could think of lots of things I'd like to mill. But I'm not a metalhead at all and I'm surrounded by woodheads (maybe I need to come up with some new terms...LOL). I've gotten used to calling my bits "end mills" from hanging around my metalhead brother, but that's about it. ;->

I've got a lot of learning to do.

...Ath

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I'd say get a higher speed subspindle for cutting shell, those little cutters do not like low RPMs at all. I had to finish up some shell cutting without my turbine once, and it wasn't pretty. 25K is adequate, 65K is the usual, and 90K works awesome but the bearings on those turbines cook really quickly compared to the 65K ones.

So far as the machine goes, shell uses very low feed rates so I doubt you'd ever need more feed than the machine has. If there's backlash in the way they've CNCed it, then you'll want to get a handle on that, but otherwise I don't think you'll have any problem with the hardware. You can do longer pieces than the process area if you're really clever with your fixture designs and setups.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

It's not actually my machine. From what I can tell the guy probably only had about $1000 - $1200 in it before he passed away. It ended up in the shop of a local acoustic builder. He wants me to get it up and running to do his headplate inlays, maybe some bridges, etc. Then I can do whatever I want with it for the rest of the time. I didn't realize it was a micro metal mill until we went to pick it up.

I'm willing to put a small amount of money into portable things like Mach3 that'll I need on any machine. I'd LOVE to have a high speed spindle, but all the ones I've seen are pretty expensive. More than the cost of the basic machine. I'll see how it runs when I get the new belt. If I can get it running and milling lower speed materials, then maybe I'll consider hopping it up.

Grizzly still sells that $23 "Micro Air Grinder" that's 56k rpm. I know some people are hand routing shell with them (not me - I use a Foredom TX). I'm in a seriously cash-poor situation right now but even I'd like to put a little more $ in it just for my personal confidence in the tool. ;->

Is there such a thing as a low-cost high speed spindle?


I was wondering about this! Particularly for routing non-contiguous things like fretmarkers. I'd love to be able to rout a set fretmarkers for the electric builder in whose shop this thing is currently living. He was the one who orchestrated the deal to get me to work on this machine in the first place. If I actually get it doing anything useful for me, I do owe him something.

Thanks,
...Ath

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I have a copy of Rhino back in the states that you would be welcome to once I return home. I have no use for it anymore as I no longer own a PC. My biggest complaint with Rhino is that it doesn't work on a Mac without running bootcamp, which in turn would open it up to all of the wonderful viral vulnerabilities that PCs come with. I have a ton of graphic imaging software and files on my computer and the proposition of losing any of it to bootcamp is not worth the price I paid for Rhino.

I think it's still in my office, but it could be in storage. I won't be back in the states until sometime at the end of summer though. If I am not mistaken, it came with 2 software keys and I only used one. If you come up with another option, don't hesitate to use it. I just thought I would throw it out there as a possible solution.

Wow, that's great!

I was just looking at Cut2D and wondering how long I could hold out with that importing Illustrator files. Maybe until the end of summer. Though a lot depends on what the machine ends up being able to do.

I so know what you mean! I was bummed that Rhino was PC only. There was supposedly some R&D effort to get a Mac version going but I think it stalled. The bugginess of Lightwave for the Mac makes me leary anymore. It's really sad because the PC version was rock solid.

I have an old Quad G5 with a 30" Cinema display that I got in trade for doing some 3D scientific illustration. It's not even connected to the internet right now. I use the PC mostly for e-mail, web surfing, playing mp3s, etc. I do some user interface design so it's nice to have a more "normal" machine with a smaller monitor. I realize that I'd have to run Rhino on it. It might force me to finally upgrade the poor thing.

Thanks!
...Ath

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I don't know what your PC specs are, but if it is dated at all, you will likely need an upgrade. I used Rhino on PC and Mac. Get this, my most recent college added a Mac lab specifically for running graphics programs. Next door and across the hall they have PC labs. I took a 3D class and what do they use? Rhino. Where do they decide to hold the class? Mac lab. Brilliant right? So they ran bootcamp on every computer. Crashed and ruined nearly every one of them. So they upgraded to intel based Macs, which worked, but would constantly freeze. My PC laptop didn't fare much better and it was brand new. Rhino is a good program but you have to the power to run it, else it's worthless.

Meanwhile I was wondering why they didn't just use Maya??? Sure, it lacks the precision of Rhino but we didn't need precision for our purposes anyways (animation). Better yet if they wanted to use Rhino so badly, why didn't they just use the lab across the hall?

Unfortunately the gene pool is getting shallow.

The PC meets their min requirements. It runs PS 7 and an older version of Lightwave ok. It just takes forever for decent sized radiosity renders. It won't have to do anything like deal with my models of entire finished guitars...LOL. Hopefully one little part at a time won't kill it - else it's upgrade time.

I have never trusted those simulators. Not using Maya for animation is really silly!

...Ath

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I just emailed someone from my office to see if they can find it. I really have no recollection of where it is. Hopefully they can find it.

Weeeehoooo!

I'm dreaming of bridge designs as we speak. That's ultimately what this thing is going to be best at. Prototyping small parts. I've seen a couple people mill wood with it. No shell so far. If I get the 4th axis working (and afford software to drive it) I could make some nice knobs.

I've also seen the cutting head replaced with something like a laminate trimmer in several cases. One guy used a Bosch Colt. 35k rpms and a little over a $100. Not bad. PreciseBits even has a precision collet for it -I do worry about runout on those things. It's not a continuous duty unit and even the guy on the web pointed out that he has no idea how long the thing will last. But if I can make a mount for it, it might help me get my feet wet milling shell.

Not that I don't have a butt load of other materials, but I don't know if they'll be better or worse. I've seen a lot of guys milling delrin and wax. But so far no suggested feeds and speed for recon stone, Corian, acrylics, etc. Hey... I wonder if it could cut real stone. I've got some nice thin stone slabs I've wanted to use for a few small accents. It's too heavy to cover a fretboard with, I know. But damned tedious to cut with one of those diamond jeweler's saw blades. Maybe I can get a diamond bit. Time to cruise Ganoskin and such and see if anyone has any tips. I seem to remember the speeds on the little bandsaws for that being slow - like a metal saw. I'd need to use coolant, I know.

Yes, my mind is racing!

...Ath

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I do not know about the Bosch unit, but the Porter Cable laminate trimmer (about the same price) is a popular choice for a small/first spindle. On my first CNC machine, I was running the thing for hours, and never had a hiccup. In fact, it is still running!

Bear in mind, they do spin at high RPMs and those things are LOUD!! You can get a variable speed controller for it (cheap at any woodwork shop) and that will give you more flexibility over speeds and feeds, and if slower, tame the sound a bit...

Run out on the unit was not bad, but a better collet will certainly help...

I would also imagine that you have plans for a VERY good dust collection systems, as abolone dust is something you do not want in your lungs!

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