Transparent material, which will be both scratch-proof and break-proof?

CuriousOne

Hello.

I have certain electronic gift idea, for which I need to have custom front panel, which will be transparent - to allow leds to see trough, and to be scratch proof (from daily abuse, nothing specific) and drop proof at same time. I've searched a lot but, nothing good comes up.

Even the "scratch-proof" lexan is actually quite scratchy. But provides nice resistane to drops, hits, etc. Tempered glass has excellent scratch-proof characteristics, but is very prone to shattering. I've heard once, that there's special material, in which, ultra thin layer of glass is adhered to polycarbonate base, so it works nicely against drops and scratches. But I forgotten the name, maybe anyone remembers?

Phil Pilgrim (PhiPi)

What about automobile safety glass? It's a glass/plastic/glass laminate.

-Phil

T Chap

I have been down this road, so much time trying to solve this problem. Anti-scratch, mar resistant, etc polycarbonate was never great, but glass is a chore. I ended up making a submerged jig for a cnc machine and routed glass panels, including drill holes, slots in the glass. Nothing beats the look of glass silk screened from the rear with enamel graphics. Use a 3m double sided tape to attach the glass to another substrate, then find a way to protect the edges and you will have a robust faceplate that looks great. There are companies that make faceplates but in small quantities they are very expensive.

http://nameplatesforindustry.com/faceplates-overlays/

For prototyping, I would work with one side mar resistant polycarb, refine the back side silk screen process, and see if you can work with that for a while. Machining the glass is a beast to master and get set up for, and forget finding someone to make glass panels for you with nice edge detail, only a cnc will route and bevel small panels since the larger machines require typically a 12" side for polishing. If the edges can be hidden under a material, glass becomes very simple to use. But if the edges must be exposed and look nice, that is a big investment to tackle.

Duane Degn

Is Gorilla Glass is what you're trying to remember?

I'm not sure if they sell it in small lots.

max72

If you only need leds to be seen trough,what about a 3d printed panel with pla?
You can have clear and translucent types.
A fablab or similar close could help printing them. If the parts are small/thin they can be reasonably cheap.
You could also couple laser cut wood with small 3d printed clear inserts to keep cost low...
Massimo

W9GFO

I do a lot of laser cutting of acrylic for salt water aquariums. The stuff they supply me with is very strong, high quality material. I forget what it is called but it is better than the standard cast acrylic. Extruded acrylic is terribly brittle, the difference in cast acrylic and extruded acrylic is so much that they should not share a common name. Anyway, acrylic is more scratch resistant than polycarbonate. If you get cast acrylic, it is quite strong too - not as tough as polycarbonate but much stronger than you might expect if your experience with acrylic is based upon cheap box store extruded stuff.

Duane Degn

I haven't tried these but they look promising.

Acrylite Resist 65
Polycarbonate Abrasive Resistant

They sell 4" x 4" samples for $2.

GordonMcComb

What you want is a hard silicone coating over polycarbonate. Machine the polycarbonate in the normal manner (you can also laser it, but you will need to clean up the edges), then do the coating. It's the same type of coating used for eye wear and automotive applications. Only glass will have a higher scratch resistance, but machining glass is not a simple process.

Finding someone to do the coating could be a trick, unless you know someone that works at an optics outfit. Some optometrists have the equipment in their offices, or they farm it out to a local business. Otherwise you start getting into some real money going to a specialty industrial source that can be quite costly.

Phil Pilgrim (PhiPi)

McMaster-Carr sells Gorilla Glass in small pieces, but it's breathtakingly expensive.

-Phil

W9GFO

GordonMcComb wrote: »

What you want is a hard silicone coating over polycarbonate.

Ahem, silicon not silicone... unless there is a type of silicone that I am not aware of. Not that there aren't thing that I am not aware of, I am sure there are many...

W9GFO

Hmmm, these guys call it hard silicone too,,,

http://www.exxene.com/core-products/hardcoats/

I am so confused. I found another place that talks about hard silicone. Seems like an oxymoron to me. How can silicone be hard???

GordonMcComb

As noted, it is a thin-film application of a silicone-based polymer. Been around for a few decades. "Hard" is a misnomer.It doesn't work by making a hard protective shell, per se, but literally lubricating the surface. The lubrication prevents one surface from gouging into the other. Think Slip-and-Slide versus just plowing directly into the neighbor's lawn. (Years ago, when everyone only saw in black and white, Mr. Wizard showed a little diagram of something similar, using -- I recall -- vegetable oil).

The polycarb Duane noted might also do the trick, though I'm not familiar with the properties of the 3M coating used:

http://www.tapplastics.com/product/plastics/cut_to_size_plastic/polycarbonate_sheets_ar/517

The Tap page has a spec sheet showing the abrasion resistance is just slightly less than tempered glass, but far more impact resistant than glass. A 4" square sample only costs $2. Worth a shot.

CuriousOne

I have roland EGX-350 engraver, with diamond cutter for glass, but I need to modify construction to make submersible jig. I'm using it for engraving on glass and it works just fine. However, the glass is fragile. Regarding the scratch-proof lexan/polycarbonate, I've did a quick test - put couple of samples on keychain, and took it into my pocket for daily abuse. After a week or so, it was full of small scratches, which make it look very ugly. I'm also very sceptical about gorilla glass - I've seen many many gorilla glass covered smartphone screens shattered...

Phil Pilgrim (PhiPi)

Mail-order laminated safety glass:

http://www.dullesglassandmirror.com/laminated-glass.asp

-Phil

T Chap

Here is an early version of a submerged glass holder when I was trying to figure it out. This one used a vacuum that connected with a tube to the center section. The glass sat on top of a rubber seal, the vacuum held the raw glass in place that I had pre cut to be 1/16" larger on all sides. I had the CNC route off 1/16" on each side to create a perfect rectangle. After several passes to cut the sides, the last pass would drop the tool down to do the bevel on the top side edge. After this version, I changed to a version that had a glass suction cup mounted inside the jig, you would place the glass on the surface, then pump the button and tighten it up. This was much better than dealing with the vacuum process which was a hassle on a lot of levels. The problem with a smaller piece of glass is how are you going to hold it in place if you need to route all 4 sides?

Machining glass requires 100% flood at the cutting tool contacting the glass. Even 1 second without flood and the tool melts.

Here is the router I used, it will cut the glass and put a bevel if you need it.

http://www.crlaurence.com/crlapps/showline/offerpage.aspx?Productid=11890&GroupID=5763&History=39324:386:5739:5758&ModelID=5763

http://www.crlaurence.com/crlapps/showline/offerpage.aspx?ProductID=2880&GroupID=1581&History=39324:1220:1551:1554&ModelID=1581&pom=0

Mark_T

W9GFO wrote: »

Hmmm, these guys call it hard silicone too,,,

http://www.exxene.com/core-products/hardcoats/

I am so confused. I found another place that talks about hard silicone. Seems like an oxymoron to me. How can silicone be hard???

When its a cross-linked polymer I expect. That's the difference between silicone oils and silicone resins I think. Adding silica
nano-particles might be possible I'd have thought.

The ultimate abrasion resistance tough glass is sapphire glass (Al2O3), used in expensive watches/phones I believe. Not cheap.

GordonMcComb

It sounds like you've answered your own question. If the coated polycarbonate won't work, that leaves a thick enough glass that won't shatter. If someone will be "playing" with this novelty, it must be safety glass, which then makes it far less impact resistant. You cannot risk having it break into shards. Whether or not a laminated (polycarbonate/glass) substrate will work depends on the type of abuse you expect. There's a difference in durability between dropping and mere daily handling.

If you find a suitable substrate that does what you're calling for be sure to tell Apple, Samsung, and all the other cell phone makers. They'll want to know about it!

T Chap

I once had conversations with the guy that makes glass surfaces for a lot of motorola phones. He described the layers to me but I don't remember the exact makeup. It was multiple layers of thin material that had to meet a shatter proof criteria. Glass, polycarb, etc. He wanted quantities of 1 million minimum.

erco

Nary a mention of transparent aluminum thus far!

http://en.wikipedia.org/wiki/Transparent_aluminum#Transparent_aluminum

GordonMcComb

T Chap wrote: »

It was multiple layers of thin material that had to meet a shatter proof criteria.

They still will break. They just won't shatter into pieces of sharp glass in someone's back pocket.

W9GFO

I had to put clear packing tape over my son's iPhone to keep the little slivers of glass from coming off, doesn't seem all that safe but he refuses to get the glass replaced.

CuriousOne

Device I want to make, should have a poshy look, while being durable, in terms that it wont get ugly scratches and wear to extent that it will loose its poshy look. The size will be about like iphone, main frame will be made from rose wood, with real gold inserts and all that beauty should be sandwitched into high class transparent material.

Lawson

CuriousOne wrote: »

Device I want to make, should have a poshy look, while being durable, in terms that it wont get ugly scratches and wear to extent that it will loose its poshy look. The size will be about like iphone, main frame will be made from rose wood, with real gold inserts and all that beauty should be sandwitched into high class transparent material.

If the transparent material has to survive keys in someone's pocket, I think a Saphire wafer or window is one of the few things that will survive. Should be able to score and crack a wafer to size, then finish with diamond abrasives. Might also see if you can get a Diamond Like Coating (DLC) on tempered glass. If the DLC is thick enough, it should be (nearly) impervious to scratches. (point contact stresses are highest just under the surface. If the hard coating doesn't extend past this zone, it won't prevent scratches well. I.e. Aluminum Vs Hard-anodized Aluminum)

Marty

Too_Many_Tools

Ever consider gutting a cell phone and using it for a enclosure?

CuriousOne

Yes.

Since it needs machined to specific shape, and phone screens/cases are multi-layer/multi-process devices, attemt to machine them causes jaggy edges, separated layers and other unusable results.