Facet Machine

[jhwatts]

I am seriously thinking about trying to automate my facet machine. It doesn’t have to completely facet a stone from start to finish. I would like automating it as much as possible. Has any thought about the possibility of CNC retrofitting a facet machine. Any thoughts. It would really be nice if I could do something with GemCad and convert it to G code. Sounds insane but I bet it would be a fun project not to mention very profitable. People buy cut gemstones like crazy.

[mxtras]

We are definately going to need pics for this thread.....

I have no idea what a facet machine looks like and I have been around machines most of my life. I have a feeling I am not alone - I might be wrong.

We definately need to see this machine with a brief (or detailed) description of the operation and process.

Scott

[jhwatts]

I have a Mark IV found at this link.
http://www.gravescompany.com/facetin...ting%20Machine

A crash course in gem cutting can be found here
http://www.rockhounds.com/rockshop/g...ns/index.shtml

I have a small machine shop (lathe, mill, etc.) so I can make my own equipment and mods.

Any thoughts?

[mxtras]

Neat! Thanks for the education.

It seems very possible to automate the equipment, sure. But since I have never faceted a stone I have no idea what portion is art and what portion is automatable.

Automating the positioners would not be terribly difficult - it would be a task, but because the thing is relatively small it would likely be easier and less expensive than building a cutting machine that has to move a 500 pound gantry. I think you would want to use very accurate components and designs with zero backlash and high tolerances since any backlash or inaccuracies would likely be highly visibile at the intersections of the facets, etc.

Looks like a very cool trade/hobby to know.

[rustyolddo]

Jarvis Tool actually made a CNC Facetron faceting machine

http://www.facetron.com/index.html

They used to have a few pics on the website but nothing anymore, I'm sure some googling would turn it up.

Also for you DIY'ers, there are some plans to build your own faceting machine which would be a good project:

http://www.gearloose.com/newgem.html

[ViperTX]

I suspect that the reason CNC is not used in the facetting of gemstones has alot to do with the use of dops and how the gemstone is attached to the dop....I think that slight bit of inaccuracy in attaching the gemstone to the dop to facet the table and then transfering the gemstone to facet the underside is the primary reason CNC is not used in facet machines.

[rustyolddo]

Originally Posted by ViperTX I suspect that the reason CNC is not used in the facetting of gemstones has alot to do with the use of dops and how the gemstone is attached to the dop....I think that slight bit of inaccuracy in attaching the gemstone to the dop to facet the table and then transfering the gemstone to facet the underside is the primary reason CNC is not used in facet machines.

No, that's not a valid reason. When you attach the rough to the dop, you just get it close for cutting the pavilion. Upon transfering to cut the crown & table you can pick up some inaccuracy in the transfer if you aren't careful.

CNC would be ideal for faceting & prepolish but for the final polish, it will have to be done by hand in most cases. A number of facetable materials have different crystal planes and it's common for some facets to polish easier than others and that's where you have to have human interaction.

Faceting gets pretty mundane & monotinous especially getting to the pre-polish stage. CNC would be nice for that.

[Geof]

Rustyoldo has it right; it is monotonous and the final details do need human intervention. I think the biggest users of automated facetting processes are the Ekati and Diavik diamond mines in Canada's Northwest Territories.

[jhwatts]

I new it would be seriously difficult to automate the process from start to finish. My thoughts was to automate the preform steps and also if I could automate the facet cutting and ultra-laping. Then do the transfer and do the same on the opposite side. Mainly automate the indexing for the facets(single axis).

[Marc Soren]

Well, it got me started thinking about faceting again....but making very small gems hasn't been introduced into my blood yet....how about much larger ? We did make a sphere machine and we also worked out a method of going through the various stages of grit without grit, (up to 10,000 or so, and in about 1/4 the time...from 1" stone spheres to basket ball size.....)

And the reason we did not go larger is because we put it on the same table as a home brewed lap table, made from a chipper anvil....so we can now make and use up to 16 inch flat laps instead of chipping trees and petrified trees look really cool polished out.

LARGER GEMS...THAT has our interest....we would like to be able to facet much larger material than is usually associated with jewelery....We have enough room to brew and attach a big arm....just got too carried away with other stuff....so it got sentenced to the dungeon of CNC parts and supplies.

My question has to do with holding stones (semi-precious, jaspers, agates, jades, and so forth) onto the large spinning lap....

1. since we would be creating REALLY LARGE "facet jewels", could not the process be automated and using vacuum instead of DOP?

2. Using larger facets (pardon incorrect use of lapidary lingo here) and perhaps vacuum, could most stones be faceted without DOP (would not need the precsion, right?) but also by USING TWO OR AT THE MOST THREE MOUNTINGS VIA VACUUM CLAMPING?

NO DOP...JUST TURN UP THE "VACUUM CLAMP" ON THE ARM.....and use one of the adapted arm designs to be built using existing CNC machine tools, and so forth???

gadz...just what we need....more unfinished projects in the dark closet of machine tool mystery parts....

POSSIBLE? or just wheel the sphere machine/monster lap machine into the closet again??? (hmmmm....better make a couple more spheres while it is out...no takers out there for trading laser for driver development, etc.)

Marc and boyz....
still holding out for a laser swap....it really works!!!

[jhwatts]

Who is we to start with? I suppose you could use a vacume to hold the stone. You could lap oneside by hand to start with and vacume to that side. How large a stone are we talking? Could you post a few pics of the sphere machine? I would like to see it. I have always wanted a sphere machine.

[MIKE JEFFERS]

saw this & thought of you
http://www.theengineer.co.uk/Article...e+the+rest.htm
mike