Cutting (gorilla) glass

[tALSit de CoD]

Hey peeps!

I need to cut some glass to form a window for a project of mine, and I would like some advice.

I've bought some iphone screens, and am going to try to cut them to size.

I contacted Corning (the original inventor/manufacturer) and also one of their distributors, and they both claim that gorilla glass can't be cut after its treatment, it will just shatter. While I would tend to believe them for mass manufacturing, something tells me that they are just trying to push their custom service, along with quality and yield guarantees.

So I want to try cutting my own. I was going to try using a scribe and then just snapping it. But then I read that some manufacturers use a CO2 laser to "trigger controlled thermal cleaving (CTC)", and then they snap it. But they don't state laser power or whether there's any surface treatment or anything else.

Has anyone tried anything similar?

Hints and tips most welcome!

// tal...@talsit.org
// +81 90 6736 1127

[Terry Dawson]

Talsit,

I have no experience with it at all but it struck me as an interesting question. In the process of doing some reading about it I turned up this reference which seems relevant to your question: http://www.lia.org/blog/2012/02/laser-glass-machining-for-consumer-electronic-devices/

regards

Terry

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[tALSit de CoD]

Hey, yes, that's the link I quoted from. They quote power/etc for direct abalation, but not for scoring.

// talsit.org

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[Terry Dawson]

I see. I assume direct ablation is not an option.

That article suggests they had difficulty cutting without cracking, even with direct ablation.

Corning might not be lying :-)

Terry

[tALSit de CoD]

But they may just have low-yields, which is not desirable for production, but for me, that i need 5-10, it should be fine.

// talsit.org

// +81 90 6736 1127

[Tim]

Regular class can be cut by heating it then half submerging it in water. It often (sometimes?) cracks neatly along the water line.

Gorilla glass may behave the same?

Tim.

[Cody Sheridan]

Gorilla glass is toughened glass as I understand it, and toughened glass CAN NOT be cut.

I believe ada tried engraving a phone screen and it cracked?

Regular float glass can be easily cut by scoring it with a glass cutter then snapping it, they cost about $5 on ebay for a good one lol (ok maybe like $10 I dunno).

Kind Regards

Cody Sheridan
Waverton NSW 2060

President - Marine Aquarium Society of Sydney

Marine Aquarium Societies of Australia

www.codysheridan.webs.com

[tALSit de CoD]

It has to be 1mm thick maximum, and relatively tough.

// talsit.org

// +81 90 6736 1127

[Cody Sheridan]

Smallest I can see on the sydney glass website is 2mm, I am sure they can toughen that. Maybe contact a few glass places and see if they can get 1mm and toughen it for you. Have you considered acrylic?

[tALSit de CoD]

I'm currently using polycarbonate, and cutting it by hand - I just want something more ... scratch-free!

// talsit.org

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[Arik Baratz]

Perhaps you can take regular glass, cut to size/shape, then send it off for tempering?

-- Arik

[Cody Sheridan]

That is what I recommended above, the only issue is getting 1mm glass

[Arik Baratz]

Sorry, missed that message...

-- Arik

[tALSit de CoD]

So, I went ahead and tried it, and documented it, you know, science and all, photos below.

First cut was pretty nice actually, worked well. The edge is crappy as hell, but I don't care, it's going to be siliconed up or something. It just scored it, and then a light snap broke off quite nicely. But I thought that maybe I used too much power, since snapping it was super easy. So I took the power down, and then the next edge was very hard to snap. So I tried with more power...........

Yeah, about that.

The glass started cracking along the edge of the score, quite slowly. You could hear a crack every 2-4 seconds along with a new "X" along the score. So I left it there for about 4 minutes until practically the entire line was covered in "X"'s. I don't have any eye protection at the lab right now (yeah yeah, I know, I know!) so I grabbed a cloth, and with my back turned and eyes closed I opened the laser and covered the glass so I could take it out without risking permanent eye damage.

So I consider this to be a partial success, the success being that I cut glass along the lines I wanted, but the partial because I never want to look at this particular piece of glass with unprotected eyes (*).

Photos, video:

https://www.dropbox.com/sh/tdbg7ihtvmauaym/KvhwQLMiko

(*) The main reason I don't want to risk it is because I don't enough about how this glass works, and, also, because of this: http://www.youtube.com/watch?v=xe-f4gokRBs

// talsit.org

// +81 90 6736 1127

[Cody Sheridan]

good to know what happens :)

[Nick Johnson]

That sounds like pretty much what I'd expect from tempered glass. It should be safe to look at, because the whole point of tempering glass is to cause it to be less dangerous if it shatters - it tends to shatter into small cubes rather than jagged fragments.

-Nick

[tALSit de CoD]

Follow up, for, you know, science!

So after my failure (yeah, calling it a failure now, since I have no usable windows), I decided to try again, but this time, I bought myself a proper glass cutter (rated for 1-3mm thick glass, perfect), and tried again. After a couple of quick google searches on how best to cut glass (clean surface, cutting oil, rubber-backed-non-slip ruler, GOGGLES!), I gave it a go, and I'm pretty happy with the result:

https://www.dropbox.com/s/wk2autajt09ptxb/2014-02-21%2013.03.49.jpg

I peeled on side of the iphone screen protective film, oiled it up, and scored that. I had to run the cutter twice, I don't know why, but the first it leaves kinda like a tiny scratch, and the second time, the actual score. Then turn the glass over, and tap through the protective film on the scored area, and ... more or less a clean cut! As you can see from the photo, there are tiny fragments that break off, and the cut is not ultra clean, but that's good enough for me. The window will be going into a little recess in my box, with the edge nowhere near where it can be touched.

I will be doing some "strength tests" with that particular piece, as in, dropping it onto hard surfaces, taping it with plastics, dropping screws onto it - typical usage scenarios, things I expect it to survive from.

// talsit.org

// +81 90 6736 1127

[Terry Dawson]

Talsit,

I've done some lead-glass/lead-light windowing and that's not quite as clean, but pretty close to what you'd expect from normal glass from a oiled cutting wheel.

I'll be interested to hear the results of your stress testing.

regards

Terry