Full Version: Anodized Aluminum
From: Ken D. (KDEVORY) [#1]
4 Apr 2005
To: ALL
Photo settings I'm playing with:
Photoshop
Adjust until photo looks best
(edited to add: convert to grayscale and invert)
Driver
Speed = 80
Power = 15 (Material sensitive to small changes)
LPI = 500 (-5), PPI=1,000 (versa default)
Mode = 3D
Laser
Lens = 1.5"
ULS Versa 40W (60ips rated speed)
I liked 3D mode the most. The drivers halftone setting also works well. The drivers error diffusion setting works if the grayscale histogram is adjusted to the dark half. (After inverting for output, scale to the range 127-255)
I was testing these settings on the 2"x3.5" pieces available from Laserbits. On the white (engraved) areas I'm getting uniform bands appearing at a 45* angle. It doesn't matter if I'm using 3D mode, halftone, or error diffusion.
EDITED: 5 Apr 2005 by KDEVORY
From: Rodney Gold (RODNEY_GOLD) [#2]
4 Apr 2005
To: Ken D. (KDEVORY) [#1] 5 Apr 2005
Surely 3d mode varies the power according to the shade of grey?
Thats the way it works on mine. In essence you arent really getting constant power. However if you have converted the pic to a halftone image in software , you would have converted to plain black and white (same should apply in the driver - it would just be variably spaced and placed black dots to fool the eye as to being a shade of grey) and thus whatever setting you have used for black would be the default.
Try defocus the lens or use a 2" , if you are using the driver to do the 1/2 toning , try the software , try rotating the image and see if the banding rotates. Try different speeds when engraving. Check your power coming to the laser , make sure its clean and smoothed.
(lots of laser problems are a result of power fluctuations etc)
Do you have Photograv?
Regards
Rodney
From: Ken D. (KDEVORY) [#3]
5 Apr 2005
To: Rodney Gold (RODNEY_GOLD) [#2] 5 Apr 2005
I have the laser plugged into an APC Line-R 1200 to regulate the incoming power.
The banding appeared with two different photos, and my grayscale test. (adjacent blocks of gray from black to white)
Yes 3D mode varies the power according to the shade of gray. In my limited testing it gave the best results.
The banding appeared using 3D mode and the drivers "error diffusion" and "halftone" settings. Three mutually exclusive settings for handling a grayscale image.
My two thoughts were fluctuations in the lasers output, or fluctuations in the aluminum's anodized coating. For now I'm leaning toward the substrate.
From: Harvey only (HARVEY-ONLY) [#4]
5 Apr 2005
To: Ken D. (KDEVORY) [#3] 5 Apr 2005
I have seen that in an apparent wiggle line going down the piece. I have reduced it significantly by blasting with about 1.5 times the needed power and brightening the final image by 20%. This gives more power per spot but smaller spots. I have found that 'halftone' works best on the ULS drivers and my system. Error diffusion is nearly as good but does not seem to have the sharpness. I do pictures on a 1x2 item, usually faces. Very demanding work for anodize.
From: Ken D. (KDEVORY) [#5]
5 Apr 2005
To: Harvey only (HARVEY-ONLY) [#4] 5 Apr 2005
Have you tried using the driver's 3D setting?
This is probably a good reason for me to revisit the other two methods you mentioned. If only time were unlimited.
What LPI are you using?
From: Harvey only (HARVEY-ONLY) [#6]
5 Apr 2005
To: Ken D. (KDEVORY) [#5] 5 Apr 2005
Never tried the setting. I just basically blast away and compensate the image prior to sending it. That eliminates most of the variance of the anodize. I began with a setting for blue, red, and then black & others. Blue needed the most power, red the next and the rest less. Blasting away not only works for all colors, but eliminates many imperfections in the anodize.
From: Sei (SEIMA) [#7]
12 Apr 2005
To: Ken D. (KDEVORY) [#1] 12 Apr 2005
Sounds like dirt or wear to the belts, bearings, and/or idlers on both axis to me. Causes a bit of distortion in the laser path, varying where the beam hits the material slightly.
How long since you replaced these parts?
Sei
From: Harvey only (HARVEY-ONLY) [#8]
12 Apr 2005
To: Ken D. (KDEVORY) [#5] 12 Apr 2005
Some questions that just appeared in my brain.
Is the pattern the same in more than one piece? If yes, does it change if you change the placement of the piece? Retest it, let's say starting at 6" margin on the left and 6" margin on the top. That puts the mechanical in a very different position. Same exact results=imaging/software/tube. Different results=probably mechanical problems.
From: Ken D. (KDEVORY) [#9]
12 Apr 2005
To: Harvey only (HARVEY-ONLY) [#8] 12 Apr 2005
Sei & Harvey,
More then one piece, Yes, but all the same material from the same bag.
I'll see if it shows up on other items/materials/lots.
Yes, it shows up on different test pieces that I was moving along the x axis. (each test was done adjacent to the previous in Corel.) I made my way across the top row, stopped before starting the next row.
I got the laser the end of last summer. Its not too old. And I'd say the use has been light. The bearings look good. They're spring loaded on the Versa so they should work even with wear. (which I don't see.)
The dots don't appear to be out of place when viewed under magnification, and aside from the superimposed 45* lines the image appears good.
From: Harvey only (HARVEY-ONLY) [#10]
12 Apr 2005
To: Ken D. (KDEVORY) [#9] 12 Apr 2005
Turn the piece at a 45* angle and see if the lines look the same. It sure will say if it is the material, a big possibility.
From: Ken D. (KDEVORY) [#11]
12 Apr 2005
To: Harvey only (HARVEY-ONLY) [#10] 12 Apr 2005
Now why didn't I think of that... :-)
I'll let you know how it goes...
From: LaZerDude (C_BURKE) [#12]
12 Apr 2005
To: Ken D. (KDEVORY) [#11] 13 Apr 2005
Ken,
Could you post a picture of what you are doing so we can SEE the problem?
My limited experience doesn't allow me to offer any suggestions, but I would like to learn vicariously through your project. :)
Thanks
From: Ken D. (KDEVORY) [#13]
13 Apr 2005
To: LaZerDude (C_BURKE) [#12] 13 Apr 2005
OK here it is. How can I not reciprocate when I'm learning so much vicariously through your projects.
This is a composite. the middle photo is pasted from another photo taken from the back of the same piece. All photos were engraved at the same size, approximately 1"x1.4". (My photo did not capture all the detail in the picture on the right.)
I think it was Harvey that suggested engraving a block in the corner then rotating the piece 90* and engrave block in new corner. I have not tried that yet, but now suspect it will show the laser as the problem. - There are some pieces I engraved portrait others landscape; they all have the same angle. I will confirm by doing both on the same piece.
To moderators: When saving the image, Photoshop said it should be below 50K, it turned out a little more. I didn't want to risk loosing the detail of the 45* bands. (cropped, resized, black&white) I also wanted to show the 3 variations referenced in an earlier post.
From: laserman (MIKEMAC) [#14]
13 Apr 2005
To: Ken D. (KDEVORY) [#13] 13 Apr 2005
Ken,
Looking at these pictures it looks to me to be mechanical. The possibilities are belt tension and or a bad bearing. I will try to find the instructions on how to tension the belt and e-mail them to you.
I would try this first to see if it changes anything.
I can not find your e-mail Add please let me know and I will send you a pdf on instructions for belt tensioning.
EDITED: 13 Apr 2005 by MIKEMAC
From: Ken D. (KDEVORY) [#15]
13 Apr 2005
To: laserman (MIKEMAC) [#14] 13 Apr 2005
I'll send you an email with all my contact information.
I believe I have the service procedures for the versa on CD rom. I believe they cover the "how to" details of the various adjustments, I'll need to check. I don't think they cover troubleshooting. How do I know which belt/axis/bearing I should be checking? What am I looking for?
Thanks
EDITED: 13 Apr 2005 by KDEVORY
From: laserman (MIKEMAC) [#16]
13 Apr 2005
To: Ken D. (KDEVORY) [#15] 13 Apr 2005
From: Ken D. (KDEVORY) [#17]
13 Apr 2005
To: laserman (MIKEMAC) [#16] 13 Apr 2005
I got the PDF. I was surprised by your comment to try loosening it first. I need to dig myself out of piles of papers before I can do anything with the laser. (its under several piles.)
From: laserman (MIKEMAC) [#18]
13 Apr 2005
To: Ken D. (KDEVORY) [#17] 14 Apr 2005
Ken,
I think you would be surprised what belt tension can do, The reason to loosen first is to see if it makes a difference. You can always put it back the same way if it does not correct the problem.
You won't have to loosen it much to see a difference. Let me know what happens.
From: Ken D. (KDEVORY) [#19]
16 Apr 2005
To: laserman (MIKEMAC) [#18] 18 Apr 2005
Mike,
Looks like I solved the problem. You were correct with the x belt, but it wasn't the tension.
I always try to keep the optics and bearings clean, I tend to be a little more lenient with the belt. (Its much more time consuming.) Prior to the anodized, I was working with wood. The belt still had a whiteish film on it. I figured the wood dust isn't too abrasive relative to many other materials: stone, glass...
I just took the time to really clean it. The diagonal stripes went away. Amazing.
What is the easiest way to clean the Versa's belt? I used denatured alcohol on Q-tips. (It took several.)
From: laserman (MIKEMAC) [#20]
18 Apr 2005
To: Ken D. (KDEVORY) [#19] 19 Apr 2005
Ken,
I would just use an old soft toothbrush with the alcohol It should work fine for that.
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