[LHC]

Hi folks -
Joined the forum here a day or so ago and have not gotten much work done at my desk since

Has anyone come across a version of these mdf cnc machines that have been set up for scoring glass? My fiance and I are into stained glass projects lately and I was thinking, that a gadget that would be able to score the lines from a pattern would be slick. The catch would be that the scoring head would have to remain tangential to the curve and although I see that the mach software supports this, I have not seen anyone that has come up with a motorized head to swivel the cutter.

Anyway, if anyone knows where I might go to see some ideas/options, that would be great.

Cheers,
Lewis

[ShayArnett]

I saw some machines for cutting cardboard/foam/neoprene etc that use a tangential knife... keep the tangential part and substitute the scoring blade and your good to go

[LHC]

I saw some machines for cutting cardboard/foam/neoprene etc that use a tangential knife... keep the tangential part and substitute the scoring blade and your good to go

I've been searching for some home-brew versions like this but haven't come across anything yet. Another idea that I had was to use an air cylinder for the Z axis to raise/lower the cutter assy. That way, you can asjust the scoring pressure and also take care of different types of glass that have a non uniform surface. Blindly lowering the scoring cutter to a certain depth will not work.

[phillby]

Just a thought, What about spring loading the cutter?

[hugo carradini]

I all sow run a stained glass studio and would be really interested in learning more about these possibility.
Thanks for any help.
Hugo Carradini

www.vitrales.com.ve

[LHC]

Just a thought, What about spring loading the cutter?

I thought about that, and it would probably work but I think you'd need a way to "tweak" the tension of the spring to fine tune and the "down/up" movement might be a little abrupt - i.e. you don't want to have the cutter come crashing down too hard - after all - you are landing on glass

The beauty of the air cylinder would be that you could easily adjust the pressure with a small regulator, as well as controlling the speed of decent/rise with a needle valve. The compressed air approach would be more cash than a spring, but I think it's far more "controllable". Not to mention the wow factor would be just huge with the "hissing" of the cylinder as the cutting head was moved up and down - haha

Looks like we have a few more souls interested in this as well as myself - hopefully we can collectively come up with some ideas.

Cheers,
Lewis

[svon89]

Some time ago I read somewhere.... I looked it up I couldn't take not remembering.
Would something like this work with a glass cutting wheel?
http://www.cuttingedgecnc.com/vinyl.htm
Check out the blade holder take 5
Stephen

[Graham S]

I like the air cylinder idea, you could make it two stage, apply low pressure for tool down, apply higher pressure for scoring force. Use high pressure for retract.

I saw some automated glass cutting on "how its made", the machine pulled a diamond scribe across the glass and then went around with a little blowtorch, the thermal shock finished the cut. Very nice!

It shouldn't be too difficult to make a spring loaded or air loaded scoring tool. I'm sure you could even make a CNC blow torch if you wanted.

Graham

[greybeard]

The diamond point glass cutter that I use for manual cutting is pivoted, with the point about 1mm trailing the pivot. I would think that the accuracy of this would be more than sufficient for it to be used to score the patterns without any mods.
Mind you, I've not cut a rough surfaced glass. Are both sides uneven ?

[LHC]

The most common cutters (at least around here) that I have seen are carbide wheels in a little metal holder that pivots about 30 degrees each way in the end of the handle (barrel). The metal pivot and wheel can be separated from the cutter handle and re-mounted into a custom machined mount on a CNC machine easy enough, but using it like a drag knife and not a true tangential axis controlled cutter is something that I am not sure if it will work or not. If it did, it would certainly simplify the mechanism. Might have to tinker a bit and test it.

The two stage force and blowtorch ideas are excellent ones. I never tried thermally shocking the glass to separate it, and as soon as I get home tonight I'm going to be digging out the propane torch and some scrap glass to try that out.

The unevenness of the glass is not that severe - and there is usually one side that is a "smooth" side per se to cut. But it is "wavy" on some types of glass - hence the need for some "springy" force to apply the cutting wheel onto the glass and follow the hills and valleys. If I had to guess I would say that worst case would be 0.025-0.035" unevenness - at least on the type of glass that I have used.

The more I think about this project the keener I am getting - guess I'm no different than all of you fellows !!

[buscht]

I've been thinking about a different approach for stained glass.
I think Gryphon makes a glass cutting bandsaw. I would like to put a X-Y CNC table on the front and simply move the glass around the blade. The advantages would be that intricate shapes would be easy to do.
I've never used this bandsaw so I don't know if it would work, but I've hooked this setup to my scrollsaw and it works pretty good.
Trent

[LHC]

I've been thinking about a different approach for stained glass.
I think Gryphon makes a glass cutting bandsaw. I would like to put a X-Y CNC table on the front and simply move the glass around the blade. The advantages would be that intricate shapes would be easy to do.
I've never used this bandsaw so I don't know if it would work, but I've hooked this setup to my scrollsaw and it works pretty good.
Trent

Interesting idea. I have not used a glass saw but have seen them in action. I am thinking they might be painfully slow - even for the hobbiest. The instructor was using one at the place my fiance and I took our begineer class at, and while it looked slick and would make cuts that could never be done by scoring, it did seem very slow.

I was going to try the blow torch / thermal shock technique at the house last night when I got home as a technique to separate already scored glass, but could not find the torch! Might have to go buy one today just to see if it works on the art glass that we use.

Have you got any pics of your scroll saw cnc set-up? I'd be interested to see it.

Cheers,
Lewis

[keithorr]

I put a home made toolholder into a 1/2 inch collet on my cnc router. Same as a previous post, the pivot point was just ahead of the following wheel. The tool would pivot in the holder like a caster wheel. I was cutting a lot of circles. I did have to manually edit the G02 values to get the offset figured out for the following wheel. The cutting pressure was from the spring built into the Toyo cutter, which was bastardized to make the unit. I used a TC-10 wheel that I also use by hand for following patterns.

[LHC]

I put a home made toolholder into a 1/2 inch collet on my cnc router. Same as a previous post, the pivot point was just ahead of the following wheel. The tool would pivot in the holder like a caster wheel. I was cutting a lot of circles. I did have to manually edit the G02 values to get the offset figured out for the following wheel. The cutting pressure was from the spring built into the Toyo cutter, which was bastardized to make the unit. I used a TC-10 wheel that I also use by hand for following patterns.

Thanks for the input. It's encouraging to hear that there are people that have gotten this to work. Is the CNC router a DIY machine, and do you remember how fast you were moving the cutter across the glass?

[Graham S]

If you want to do tangential control then Mach3 has it built in I think.

[diarmaid]

Hi LHC. This may or may not be useful but have a look at this thread re. Laser for glass engraving.http://www.cnczone.com/forums/showthread.php?t=20332

Im sure a powerful enough laser cnc would be useful for cutting aswell but Im not sure what your budget is or requirements are.
Look at sidi-steves info and pics for the little IE300 engraver. Im new to all this but its fairly cheap as retail cnc lasers go ($999). Also on page two I have a .jpg pic posted that steves engraving on a glass pane to let me see how it looks with this machine.

[buscht]

Lewis, here is a picture of my CNC scrollsaw. You can't see it in this picture, but there is another linear rail on the other side of the machine. I have 2 rails in the Y axis and one rail in the X. It cuts about 4-5" per minute through 1" material.
That sounds slow, but you can do other things while its cutting and you can count on the dimensions being consistantly accurate.
It just 2 axis. I had a 3 axis Xylotex card that I blew up one of the axis, but it works perfectly for this application.
I'm pretty sure that something like this would work for small stained glass pieces, under 12" x 12" (300mm x 300mm) but again, I don't know how well the glass cutting saw works.
Trent

[PBMech]

We specialize in glass processing equipment. It would not be difficult to produce a CNC contour scorer. We have produced CNC linear scoring tables and scoring/breaking machines.

Paul Brake
PBMech Consulting
[email protected]

[awerby]

In the case of a knife, which has a certain directionality, I can see it, but for a diamond point which can cut in any direction it seems like something that wouldn't be needed. More useful, I'd think, would be a spring-loaded head to hold the scoring tool, so it wouldn't hit the glass too hard on the descent, and could accomodate slight variations in glass thickness. Most of us here could probably make something like that in our shops, but here's something that might work off the shelf: http://www.2linc.com/glass_engraving.htm

Andrew Werby
www.computersculpture.com

[amplexus]

I'd use a spring loaded diamond cutter with a conventional stepper to drive the z axis, it should give you finer control than a pneumatic cyl. Air regulators tend to creep but a good pressure sensor and a pid loop could be done. A pinpoint torch should give you good fracture control.
Amplexus