Etching Glass

[Howley]

I have attemped to etch glass using a vcarve bit at 20,000 RPMs at .005 to .0025 depth. I've got mixed results from cracking the glass to ruff edges.
Also because I'm dealing with such small amounts of depth, any differences in the table or material cause the bit either go to deep or miss the surface all together.

Any Comments?

I'm assuming I should just purchase the diamond drag bit with the spring loaded tip from our friends at shopbot?

Does anybody have experience with any other bits?

Thanks in advance for any input!!!

John

[curtiss]

I placed the glass on some "can cooler" foam at each corner that allowed some vertical movement.

Just used 2x tape / not a lot of side to side pressure with this, worked pretty well.

[ssflyer]

I've never tried with anything but a diamond drag bit. I've had great results, including text down to about 0.01" tall!

[Brady Watson]

You need more RPM than your spindle is capable of delivering...Look into a TurboCarver or similar that spins 400,000 RPM. It uses diamond tooling & can drill a hole in a light bulb, egg or whatever without cracking it. I would still advise using water as a coolant if you intend to profile cut.

-B

[Xray]

Yep, drag bits work great on glass - Not all that visible though unless it has some type of backing or edge lighting.

[gene]

go to the legacy woodworking site . They have a post on doing glass etching on a cnc , i think that i saw it on you tube . I will try to find it and post a link

[gene]

Go to you tube and type in legacy glass etching and it should pop up

[Howley]

Thanks for all the input!!
I will probably order the drag bit from Shopbot.

[Howley]

If I zero out this bit to the surface, and the bit is spring loaded, what is a good depth of cut to start out with?

I understand it depends on the material, but say I'm etching a glass mirror, in vcarve pro what might be a good depth to start at to get the spring under compression?

:rolleyes:

[Brady Watson]

If I zero out this bit to the surface, and the bit is spring loaded, what is a good depth of cut to start out with?

I understand it depends on the material, but say I'm etching a glass mirror, in vcarve pro what might be a good depth to start at to get the spring under compression?

First, flatten that spoilboard...then read the distructions: RE (http://www.widgetworksunlimited.com/CNC_Diamond_Drag_Engraving_Bit_p/cnc-dmnd_engrv-250.htm)



CNC Machine Diamond Drag Engraving in 3 Easy Steps


STEP 1: Create your CAD/CAM file (G-Code) using the same software and methods used to create standard 2-D cut files. (Detailed instructions on creating cut files, including recommended feed / speed rates, are included with the bit.)

STEP 2: Secure your part to the spoilboard with vacuum pressure, clamps, screws, double-sided tape, etc. Insert the CNC Diamond Drag Engraving Bit in your 1/2" collet (router/mill) or mounting bracket (plasma torch) and set your bit height / Z = 0 level.

STEP 3: Run your cut file to engrave your part. The spring-loaded, "floating head" style bit applies constant pressure on the diamond tip. As your CNC machine drags the diamond tip against your part, it creates very precise, permanently engraved lines on the part's surface.

-B

[Xray]

.008 or so depth works for me, I then lower it until it slightly compresses and zero it there. No matter if you use high pressure or low you are going to get a scratch in hard material, which is just what you want ,,, And the difference is not all that perceptible.
There is also an adjustment on most of these to vary how easily in compresses, I set it about mid way and haven't had the need to readjust in 100's of etchings.
[BTW, I wouldn't pay near that much for one of these, this one is the same from what I can tell for half the price]
http://www.ebay.com/itm/1-4-DIA-DIAMOND-DRAG-ENGRAVING-BIT-STAINLESS-BODY-TAIG-SHERLINE-CNC-MINI-MILL-/281252869899?pt=LH_DefaultDomain_0&hash=item417bfa370b

Not trying to cut anyones sales, and if the widget model offers advantages over this one, feel free to point them out. Near as I can tell, the only difference is the spring pressure can be adjusted on the widget model with the tool in the collet I think, one I listed above needs to be out. Almost a non factor, as this doesn't need to be adjusted much, if any.
No, I am not the ebay seller, and yes I use this one and highly recommend it. Would also recommend buying a spare tip at time of purchase, $20 I believe.

Here are a couple I recently cut in plexi giving an idea of some of the detail these are capable of

http://www.camheads.org/attachment.php?attachmentid=7120&d=1387078532

http://www.camheads.org/attachment.php?attachmentid=5336&d=1365305552

[bcondon]

Sandblast?