Yanxin, your coming right along............ makes me happy.

Brett

Brett,
Are you not hooked yet?  Guys, we need to team up on him

John, I have been hooked for a while.  A good friend of mine was one of the guys that helped Artcam with path generation for Lithophanes.  Loved the idea and now the availability of parts and information enabling us to use lasers really excites me.  I often wonder what will be next and find some others efforts truly inspiring.  Many of those others have posted in this thread.  Marcel Beaudry's tiny cubes in cubes and a host of others come to mind.  Tom Hubbin was working on 3d laser scanning before he passed.  In a world where most refuse to think for themselves in order to accomplish trivial things, I come here and see the exact opposite.  That is what I love.  People who push to be above average and refuse to let the standard deter them from accomplishing their goals.  Tweakie has always made my day in that respect.  So, will I ever get to play with lasers.......... no idea but if I live long enough I'll have at least one of everything. 

Brett

My congratulations Yanxin, this looks like you are well on your way to producing some stunning images. 

A really excellent job my friend. 

Tweakie.

Thanks, Tweakie, you are the one that always motivating me. A good start:)

  Yanxin, your coming right along............ makes me happy.

Brett

Thanks Bret, still a long way to go, those genius setup a really high standard, hard to keep up with:)

Yanxin,

Yes to Tweakie's comment - a really excellent beginning.  MDF burns dark, but your image shows very good image tonality.

The lines are something I also have a problem with.  Are you using 1/4-20 (or similar) lead screws?   That's what I believe is causing the lines, and I have just started building a small belt-drive machine to see if I can eliminate them.  Our friends who use ball screws don't have the lines.

John Champlain

Yes, I am using 1/2-13 lead screw, Y axis is not stainless steel lead screw, I have been planning to replace it and now I think it's time to do it, the other two are high quality stainless steel lead screws.  Maybe next build will be ball screws.

I reduced the power and bias current, de-focused the laser a little bit, burned another MDF, lines are still there, image is better but it's losing details at lighter color because of the lower bias current(I'll definitely implement your DAC circuit soon). Next will try de-focus more, reduce line spacing to see if I can make it better. Maybe it's the way this piece of MDF reacts with laser, will try one other type of wood too to see if lines are still there. I am having a lot of fun:)

See below picture. Sorry the MDF was a little dirty, some marks on it, looks like there are three flies on Dew's nose.

Yanxin
 

Lines are gone once I reduced the line spacing half, in order to retain all shades, I had to burn MDF darker, it's still burning, will take 4 hours to complete.

Yanxin

Lines are gone once I reduced the line spacing half, in order to retain all shades, I had to burn MDF darker, it's still burning, will take 4 hours to complete.

Yanxin

Too early to say that, it shows up as it burns more, sounds like the lead screw problem.

Yanxin,

I'm the one that developed/invented this process by varying the power to laser engrave 8bit shades and I do have to say, very good job!

Why don't you jump over to the Hobby CNC Art laser diode thread and post your results? This is a CO2 laser build thread that Tweakie started. Just a suggestion.

Jeff

Yanxin
[/quote]
Too early to say that, it shows up as it burns more, sounds like the lead screw problem.
[/quote]

Yanxin,
You might try to chase the threads of the lead screw with a sharp (new) thread die if you have one.  It might help. 

John Champlain