Machsupport Forum

General CNC Chat => Show"N"Tell ( What you have made with your CNC machine.) => Topic started by: PicengraverToo on January 29, 2013, 07:09:04 AM

Title: Mirror Lasering With Shades
Post by: PicengraverToo on January 29, 2013, 07:09:04 AM

Hi everyone,

I laser engraved on the back of a mirror by varying the laser diodes power using an US Digital absolute analog shaft encoder timing belted to my Z axis stepper motor. The 0-5V from the encoder is fed into analog modulated laser diode driver to vary the laser's intensity. This process does not require any special laser engraving software, so a rotary engraving image program will work with my process, but I prefer PicEngrave Pro 4 to generate the inverted Lithophane G-code.

The image is not dithered B&W like a normal laser engraving process, but brought into PEP4 as the original after doing some simple editing like gamma adjustment and sharpening. The Z axis depth of cut code slightly rotates the encoder which powers the laser diode up and down based on shading of the image.

The first picture is the back of the mirror after the shade engraving process which looks like a photo negative. When lighted from the back, it looks like the original photo as shown in the second picture. The third picture is showing it viewed from the front without any back lighting.

I have been using this greyscale laser engraving process to create shades for quite some time now on wood.

https://www.youtube.com/watch?v=8xGYtpW00I8 (https://www.youtube.com/watch?v=8xGYtpW00I8)

Thanks to forum member Picengraver showing us his laser engraved mirrors in the thread he started, has opened up a new way for me to create art with his software. Thanks John!

Jeff

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on January 29, 2013, 07:29:16 AM

I did this one yesterday and it's back lit.

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Tweakie.CNC on January 29, 2013, 08:43:15 AM

As always, excellent work Jeff - they have really come out well.  8)

Tweakie.

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on January 29, 2013, 12:27:54 PM

Thank you very much Tweakie!

Title: Re: Mirror Lasering With Shades
Post by: Picengraver on January 29, 2013, 07:10:17 PM

Excellent work, Jeff.

All, it is important to note that Jeff is the inventor and developer of the gray scale image engraving process using an analog controlled (not TTL) laser diode.  He has freely shared his methods with all who have expressed interest.  Larger CO2 lasers do not seem capable of reproducing an image with the same high quality that Jeff is achieving.

For those of you who have an interest, more may be read here: http://hobbycncart.com/forum/63-151-3

John Champlain 

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on January 30, 2013, 07:46:07 AM

Thank you for your kind words John!

I do have to say, excellent image to g-code creation software to you!!

A little detail of the laser diode I am using, it's a 445nm 1W with a 3 element AR coated focusing lens. I able to focus the beam down to .007" and when I engrave Birch Ply, I use a .008" pixel resolution (stepover) and can run at 50IPM.

I use a 3.33 ratio from the stepper motor to the MA3 shaft encoder and since my Z axis screw being a 2.5MM pitch (.0984") then dividing that by 3.33 gave me .0295" to work with on the 0-5V range on the encoder without changing any steps to the motor. I start out at Z-.0038" for Z zero (just before it starts to burn the wood) This is almost 1V to the modulation input on the laser driver. I set PEP4 to cut at Z-.0255" depth, that gives me 255 .0001" incremental moves (theoretical shades) from white to black. This also gives me a .0002" safety below full depth before the encoder will jump back to 0V. My Z axis only moves half the total g-code travel since it's a 2-1 ratio from the stepper to the screw and does not effect the focus of the beam.

Mirrors are harder to burn so the starting zero point is Z-.0095" more then I used for the Birch Ply, about 2V to the driver. I have PEP4 go Z-.016" more for full power. I can run these at 40IPM with a .007" pixel resolution. I found out that full power to the back of a Dollar Tree mirror it turns white. I'm loosing shades with this setting, but how many shades are there from white to mirror anyway?

Thanks again to John, I am really excited about laser engraving mirrors. I have done several Lithophanes in Corian in the past and never got the detail like I am getting with laser engraving on a mirror. Besides, Lithophanes don't look the same when back lit or not like the mirror does, which is a really cool effect in itself.

Jeff

 

Title: Re: Mirror Lasering With Shades
Post by: Ya-Nvr-No on January 30, 2013, 09:45:56 AM

I think all three of you guys are doing some great work. Always follow your threads. Thanks for posting.

Title: Re: Mirror Lasering With Shades
Post by: Dan13 on January 30, 2013, 12:23:49 PM

Wow! I didn't realise lasering a mirror could yield such beautiful results. And your way to control the laser power is brilliant!

Thanks for sharing.

Dan

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on January 30, 2013, 04:40:01 PM

Thank you very much, Craig & Dan!

It's been a very gratifying project and adventure. 8)

Jeff

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on February 11, 2013, 09:12:56 AM

My Laser diode is my brush and PicEngrave Pro 4 is my paint. Tried some white artist canvas using TTL and the texture sure gave it a real nice effect. Sprayed some clear protective finish on it also.

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on February 11, 2013, 09:24:04 AM

Outstanding Jeff!   :)

Brett

Title: Re: Mirror Lasering With Shades
Post by: Tweakie.CNC on February 11, 2013, 10:59:00 AM

Brilliant work indeed.  8)

Tweakie.

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on February 11, 2013, 11:03:03 AM

Thanks Brett and Tweakie.

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Picengraver on February 11, 2013, 01:35:33 PM

"white artist canvas"

Fantastic.  Good going, Jeff.  Another brilliant innovation from you.  You continue to push the state of the art even higher.

John

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on February 11, 2013, 05:09:34 PM

Thanks for the compliment and the paint to do it with John.  ;D

Title: Re: Mirror Lasering With Shades
Post by: Picengraver on February 20, 2013, 01:20:05 PM

Used the artist canvas that Jeff discovered to laser this one.  Clear lacquer spray for protection.  Size 6 x 8 inches.

Thanks Jeff.

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on February 20, 2013, 01:54:55 PM

Very Nice! 

Brett

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on February 20, 2013, 10:08:48 PM

Very nice John,

That came out very good. Looks like you varied the power instead of pulsing. I tried to use analog modulation on the artist canvas and just could not get it to come out that good. Please give us details on your settings.

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Picengraver on February 20, 2013, 11:42:24 PM

Thanks Jeff,
I used .007" resolution at 35ipm, max. power, and laser output setting.  I was also careful to not wipe off the burn residue before spraying on a light coat of clear lacquer.

I think a lot depends on the original image.  I'm still trying to get a handle on that aspect; I just don't post my failures  :D

John

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on February 21, 2013, 07:25:53 AM

Thanks John,

That's one thing I did not try (laser output setting) and I was not patient enough to run them at a lower feedrate.  ::) They came out OK, but was to light. Nothing good enough to brag about yet. I'm looking into a 10W laser to mount on the new build. It's a rack and pinion servo system and can run at 525IPM max with the 48V power supply I used.

Jeff 

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on March 29, 2013, 10:43:05 AM

Edited the g-code produced by PicEngrave Pro and converted all Z axis negative moves to positive feedrate instead. Ran my laser at full power and just varied the feedrate up and down to get shades on this mirror. Used Lithophane code and the lightest areas were ran at 25IPM and darkest areas were 65IPM and all feedrates in between gave it the rest of the shades in the engraving. The image is back-lit.

Title: Re: Mirror Lasering With Shades
Post by: Tweakie.CNC on March 29, 2013, 12:46:25 PM

That is quite amazing Jeff - excellent work indeed.  8)

Tweakie.

Title: Re: Mirror Lasering With Shades
Post by: Ya-Nvr-No on March 29, 2013, 12:50:08 PM

Almost looks 3D, nice job Jeff.

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on March 29, 2013, 01:23:07 PM

Very Nice Jeff!     You fellas make  me want a laser even worser!  ;D

Disclaimer!

Warning!!! These stunts are performed by professionals, please do not try this at home!!  ;D

Just wondering, has anyone tried the back side of a mirror?  Would it burn the coating off and leave it just glass?  Would it reflect and burn the shop down?  Would it leave the areas black and maybe you could wash off the coating and get some really neat effects?  I emphasise back side here and that may be a no no.   Maybe it wont work with real mirrors but would with black paint on a piece of glass?  

Brett

Title: Re: Mirror Lasering With Shades
Post by: Overloaded on March 29, 2013, 01:30:59 PM

That certainly is an awesome piece of work !
Thanks for your contribution,
Russ

Title: Re: Mirror Lasering With Shades
Post by: Overloaded on March 29, 2013, 01:34:29 PM

.... I meant Jeff's SHIP.

(your post is some nice work also Brett) ;D

Russ :)

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on March 29, 2013, 01:44:53 PM

 ;D  I try!

Brett

Title: Re: Mirror Lasering With Shades
Post by: Tweakie.CNC on March 29, 2013, 01:49:17 PM

Quote

Just wondering, has anyone tried the back side of a mirror?  Would it burn the coating off and leave it just glass?  Would it reflect and burn the shop down?  Would it leave the areas black and maybe you could wash off the coating and get some really neat effects?  I emphasise back side here and that may be a no no.   Maybe it wont work with real mirrors but would with black paint on a piece of glass?  

Brett

Doe - That is done on the back side of a mirror.  ;D

Tweakie.

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on March 29, 2013, 02:06:15 PM

 ;D  Yeah, I would think suggesting the front side would be a really bad joke, kind of hated to post it TBH but just had to know.....  

How did it turn out?  I have probably seen it already but I'm afraid I'm loosing my grip!  ;D

You guys have done some absolutely inspiring work......  makes my jaw drop.....  :)

Brett

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on March 29, 2013, 02:12:26 PM

Thanks everyone.

Brett, like Tweakie said, that mirror was lasered from the back side. The image was flipped (mirrored) then the black areas in the original image had a deeper depth of cut in Z before I edited it to a feedrate. The slower the feed the whiter it is on the front because it burns the coating off. The faster the feed, the darker it is on the front and leaves the reflection. Did not have to do any scrubbing, just sprayed a very lite coat of clear paint to protect the back from getting rubbed off from touching it.

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on March 29, 2013, 02:19:16 PM

Well Jeff, it is simply amazing............  what does it look like with the back light on and off? 

Brett

Title: Re: Mirror Lasering With Shades
Post by: Tweakie.CNC on March 29, 2013, 02:20:43 PM

Brett,

There are more examples of Jeff and John's excellent work with mirrors in this thread http://hobbycncart.com/forum/63-151-19

Tweakie.

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on March 29, 2013, 02:36:31 PM

Thanks Tweakie,

I was about to post that link.

Brett, they pretty much look the same with or without the back light which is a really neat effect. John (Picengraver) is the one that got me started lasering mirrors. His program works excellent for all kinds of engraving including using laser diodes.

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on March 29, 2013, 03:21:14 PM

Very nice work there too Tweakie...........  I'm fond of the girl and the motorcycle.  ;D

I bet the lighting makes them even cooler.......  you fellas Rock!

Got to go do some wireing now.........

Brett

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on April 06, 2013, 03:48:41 PM

Quote from: Chaoticone on March 29, 2013, 03:21:14 PM

Very nice work there too Tweakie...........  I'm fond of the girl and the motorcycle.  ;D

Brett

Brett,

FYI, Tweakie does not do any laser engravings with a diode. I did the mirror laser engraving of the girl with the motorcycle. ;)

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on April 06, 2013, 04:33:42 PM

Yup, I saw that Jeff.........I like your avatar too.  It's my fault as I was rushed and throwing it out there in short hand.  I was telling Tweakie there is a lot of nice work over on that site too and that I really like the one you did of the girl with the motorcycle.  Almost made me float a valve.  ;D
Brett

Title: Re: Mirror Lasering With Shades
Post by: Overloaded on April 06, 2013, 06:30:17 PM

Quote from: Tweakie.CNC on March 29, 2013, 02:20:43 PM

There are more examples of Jeff and John's excellent work with mirrors in this thread http://hobbycncart.com/forum/63-151-19

Tweakie.

Man, that is some keen work Jeff ! Thanks for the link Tweakie.
Btw, that is one foxy motor bike ! (I had a couple valves flutter too Brett) :)

Russ

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on April 06, 2013, 06:56:15 PM

Thanks guys,

Here is an angel to look over you two.  ;D

Jeff

Title: Re: Mirror Lasering With Shades
Post by: Overloaded on April 06, 2013, 07:25:59 PM

Ahhhhh ... my guardian angel.
Always wondered what she looked like.
Good to know my imagination wasn't too far off.
Thanks Jeff,
Russ

Title: Re: Mirror Lasering With Shades
Post by: Chaoticone on April 06, 2013, 07:47:11 PM

Well, I sure do feel better........ almost good enough to try to clear the pond on a motorcycle again just so I can see her close up.  I'd play dead until she gave me mouth to mouth for at least 5 minutes.  ;D

Very good job Jeff.......... the laser work looks pretty good too.  :D

Brett

Title: Re: Mirror Lasering With Shades
Post by: budman68 on April 08, 2013, 08:14:04 PM

wow............makes me want to just quit and sell all my stuff. Absolutely incredible work there.

I was going to post a little job I completed today, and ran into this thread and decided against it now......lol!

Thanks,
Dave

Title: Re: Mirror Lasering With Shades
Post by: PicengraverToo on April 09, 2013, 01:58:31 PM

Thank you very much Dave,

This is just a hobby for me and I have allot of fun making them. Thanks to Google images, the subject matter is endless.  ;D

Jeff

Title: Re: Mirror Lasering With Shades
Post by: budman68 on April 09, 2013, 02:51:29 PM

Yes, while the imaging may be free, it's your talent of putting it all together,  ;)

Dave