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We want to carve pearl shell. (We live near a pearl oyster farm.) The shell is somewhat uneven. We have a small laser engraving business but the laser barely marks the shell. Does anyone have any suggestions for a small CNC machine that we could use for this purpose? (FWIW, we know CorelDraw quite well but have used real CAD software only a very little bit.) Shipping weight to Fiji also is a concern. (We pay duty and VAT on the shipping costs as well as the cost of the machine.)
I would look at zenbot to start. : http://www.zenbotcnc.com
and: http://www.probotix.com/FireBall_v90_cnc_router_kit/
Also, sounds silly, but eBay sometimes has a good selection of smaller units. Another option is the DIY route, but in this case prob not the best route.
Now, I don't have any shells near me so I am unsure just how uneven they are but you might be OK with out going through many steps to compensate for the curvature of the shell.
Try CNCzone.com, those guys will help you.
Also, there are lots of open source free CAM, CAD, and machine controllers. They are a good start before you decide to purchase a program.
When looking at small CNC routers, just remember Buyer Beware! It is common practice to price these machines incomplete. The Probitix in the link is a good example, but not the only company to do this. Without the "options" the machine is incomplete and will not run! Its like buying a new car only to find out the price did not include an engine, transmission or tires!
Be sure you know exactly what will be needed in order to use the machine, and if any included software is demo or Linux based. Nothing wrong with Linux, if you know Linux.
cnczone is a treasure chest of good information.
John
i have a friend in australia who is a good cnc source, in that part of the world the 0609 quick cnc is a good little router, (the only chinese router i ever truley admired) i have his email if you want you can pm me
jim mcgrew
You might want to look at the Stinger from Camaster. It is a small routing machine, that might be what you need. And with the Aspire software you could try something like this. The Aspire software has a function where you can cut a machining path along a 3-d surface.Quote:
Originally Posted by John Noell
Since this is more for fun than any hope of serious income (this is a small island) I was hoping to get by with something less expensive than the Stinger with Aspire. (And my wife is EXPECTING me to come in a lower price point. :)) Adding in the 3d modeling software to the cost of the machine plus gcode software makes this an expensive hobby!
i spent 6 years in the virgin islands and the canary's even though we were closer to the mainland it still is a long way to the cookie jar!! i can understand
jim
I bought a Zenbot several months ago and have been very happy with it. I use Corel to do layouts and SheetCam to generate toolpaths. Zenbot uses Mach as a controller which is easy to learn for simple stuff plus there is a huge on-line community you can bug for answers to problems. Sheetcam is very simple to learn and use and is great for 2 and 2.5 D jobs - it costs < $200 (actually 110 UK pounds).
The real issue with CNC carving on shell is the location of the surface to machine. You have a limited wall thickness and VERY irregular surface. Your CAD work will have to be on a curved surface, and breakout will be a problem. I suppose with laser scanning, you could do this, but that sure won't be cheap. I thought about fine sandblasting, but getting a mask to stick on that surface won't be easy either. I'd say that despite the natural beauty, this would be one tough cookie to work on.
Richard, that is exactly my concern. I understand that some emgravers (Signature 8080+) can handle irregular surfaces for engraving, but AFAIK they don't have any way to "engrave" to various depths, which a CNC could do. Well, if the CNC doesn't work on pearl shell I can always find other ways to play with it. :) :)
You will probably find lots of other ways to play with it. My only advice is buy good software, and get the most machine that you can afford. A machine by itself or with limited software is next to useless. The rest is what the operator can do with the machine, and software. Good software will let you do far more things than you can imagine with little frustration.Quote:
Originally Posted by John Noell
Regarding buying the best machine you can afford. One you have had it and have gotten over the initial learning curve you will realize far more things that you could do than what you could before you bought it.
Hi,
I don't see this as a 3D application. I believe it is 2D with a really warped surface...
What I mean by this is I think the best way to approach a project like this is to probe the object to be engraved and generate a Z axis map of the surface. You could then generate GCODE based on the deviation from a flat Z according to XY position as probed. This is how I ultimately plan to implement guitar fingerboard engraving.
-James Leonard
Since the curvature of the shell is realtively small it might be possible to use a spring loaded engraving tool or holder - http://www.2linc.com/engraving.htm. I haven't used one but have looked at them several times. You can also get holders in which you could possibly put a very stiff steel brush. It might mark the sheel enough to be visible without shattering or penetrating it.
I don't know if a diamond drag bit would work on it but it will engrave granite and glass.
I know pretty much nothing about diamond drag but guessed that it would not give me the depth I want. I can do shallow engraving with my laser. We make very detailed coconut shell jewelry and would love to be able to copy some of those designs into pearl shell.