[rbreman88125]

I am new to cnc but have been a bench jeweler making hand made wax models since 1989 .I bought the Roland jwx 30 because it was touted as easy and made for the jeweler as opposed to a machine you needed to adapt.My problem is this,I cannot find clear information ,if it exists,in creating jewelry and small scale sculpture on this or any other small machine.I would love to find some definitive information on feed rates,cutting depths for different bits and why without wasting any more time or wax and not damaging my machine.I also would love to know cutting strategies for undercut pieces or deep cut pieces where a bit might have trouble reaching,etc.Any materials,books,online classes that pertain to jewelry or problems dealing with intricate pieces.I will be in your debt and if youre in the area i would buy you a steak dinner with top shelf liquor LOL!Just saying i will be very relieved to find some info...thanks Rich Berman

[awerby]

The JWX-30 is capable of fast and accurate carving in wax and other soft materials, and it comes with a very capable suite of software.

I am new to cnc but have been a bench jeweler making hand made wax models since 1989 .

[That should be a big help; some people with no understanding of what good jewelry models entail design things in CAD that don't really work in the real world.]

I bought the Roland jwx 30 because it was touted as easy and made for the jeweler as opposed to a machine you needed to adapt.My problem is this,I cannot find clear information ,if it exists,in creating jewelry and small scale sculpture on this or any other small machine.I would love to find some definitive information on feed rates,cutting depths for different bits and why without wasting any more time or wax and not damaging my machine.

[Fortunately wax is pretty cheap, at least in the sizes you're using, and you're unlikely to damage the machine (unless you get really frustrated). Wax cutting can be done at a fairly high rate of speed, but that goes down with the size of cutter you're using. The basic rule is that the tool has to remove enough material at each revolution to clear the path for its advance. So if your tool removes .003" of material per flute, and it has two flutes, then you can advance .006" per revolution. If your spindle is running at 10,000 RPM, that works out to 60 inches per minute. The rule of thumb for depth of cut is not to go deeper than half the diameter of the tool at a time.]

I also would love to know cutting strategies for undercut pieces or deep cut pieces where a bit might have trouble reaching,etc.

[Your machine can only cut the areas that it can reach with a tool. It's possible to design parts that it cannot completely cut, if they are unreachable. If those undercuts are important to your design, cut what you can on the machine, and go in afterwards and scoop out the undercuts by hand; it's still easier than carving the whole thing by hand. For deep areas, you can adopt the same strategy, or use a longer tool. Straight endmills tend to be very short in the small diameter sizes; to work around that, you might try a tapered tool, which is stronger since the smallest diameter is just at the end. Bits and Bits Engraving Cutters | End Mills | Tools for Milling Wax is a source for these. Another company, Precisebits, offers "deep reach" carbide tools which you might find useful. There's also a more in-depth discussion of the feedrate issue on the Precisebits site:

Calibrating Feeds and Speeds with Carbide Microtools ]


Any materials,books,online classes that pertain to jewelry or problems dealing with intricate pieces.I will be in your debt and if youre in the area i would buy you a steak dinner with top shelf liquor LOL!Just saying i will be very relieved to find some info...thanks Rich Berman

[Mmm - that sounds good; are you anywhere near Oakland California? Id suggest starting with relatively simple pieces, until you're more confident of the process and results, and working up to more complex ones. As well as this forum, there's also a couple devoted to CNC jewelry specifically that you might check out: 3dcadjewelry Forum and Jewelry CAD CAM Forum for 3D Wax Mill .]

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[rbreman88125]

your answers were very helpful ,thanks!The piece I was trying to cut was a 4 prong box for a huge emerald cut stone and top and bottom milling had to be broken into many steps because of the tapering inward of the prongs and the depth of the piece.I was trying to cut top and bottom with a rotary hub on the bottom center to finish on the rotary tip.seemed simple but it was not.my first try wasnt broken into different areas and the mill simply took off the prongs and the top rail.At this point i went in and assigned more roughing to cut the inside of the setting and then another step for the areas around the outside but i think i was making it too difficult and i overtaxed my system..out of memory?how would you go about milling such a beast ?

[awerby]

it's pretty difficult to tell you how to go about cutting it. But your machine shouldn't have cut off part of your part. I'm not sure why it would have done that, but you may have set up a machining region that didn't include the prongs, so they were ignored.

In general, if it's not possible to cut a part in rotary mode, you can try cutting it in indexing mode, which is when you move the rotary to a certain position and leave it fixed there while you run a 3-axis toolpath in a certain area. It sounds like that might be what you're doing, but it's hard to say without getting into all the details. What sort of computer are you doing your CAM on? It's less common to run out of memory these days, since RAM has gotten so cheap. Was this a really huge part file?

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software