Banding on solid black fills.

[Dan Kozakewycz]

I am having issues with vertical banding when engraving anodised aluminium. Initially I noticed this when trying to engrave a photograph but have now discovered it to be an issue on black vector fills, which rules out artwork as the cause of the problem.

Here is the banding under the loupe

http://img.photobucket.com/albums/v314/Quicksilver4000/Black%20Art%20Graphics/6B0E7DA2-1BCC-4CBB-9C49-9B6370F7A6C8_zpssqib4e00.jpg

I engraved the same black filled square twice, one above the other but slightly displaced in the X axis. The banding appeared in the same location on the X axis, which again rules out the artwork and points to an issue with the laser, at certain points on high power settings the dot size appears to be fluctuating.

I know from searching this forum that these issues are rarely solved but I was hoping that having ruled out the artwork, there might be a narrower band of possible causes for the issue?

Cheers

Dan

[Michael Hunter]

Unless the bearings and belts on your machine are supernaturally perfect, there is likely to be some oscillation of the lens holder following each change in direction.
You might be able to prove whether this is happening to you by doing a wide engraving, rather than the tiny square.

Fixes are :
Use a higher resolution.
If already at the highest resolution, slightly de-focus so that the beam is a bit wider.

[Dan Kozakewycz]

It will do it on wide engravings too. The photo I was doing was A3 size and the banding was noticeable in the lighter areas.

I will give a higher resolution a go, hopefully that will fix it.

[Scott Shepherd]

Dan, can you report your settings? DPI sent over as, speed/power/ppi, all the settings in your "advanced" settings.

[Dan Hintz]

Looks like the dot size is fluctuating on initial entry into a line (getting the tube to start lasing is not fast enough), so you may need to turn up the tickle a tad... you can see that every other line is leaving an entry mark, which says the end of the line is still at the same power as the middle, but the beginning isn't up to full power.

Second, it looks like you're getting full coverage (so dpi is good), but that also looks like bare aluminum... until you post your power, I'm going to guess you have your power way too high and you're completely blowing away the oxide layer down to bare metal.

[Dan Kozakewycz]

Hi Dan

I know you're an advocate of using low power on anodised aluminium, but I did a test ramping down the power from 100% and 70-100% produced much the same response, 40-70% produced varying (darkening) shades of silver and anything below 40% produced absolutely no mark whatsoever. This material needs quite a lot of power to produce a decent mark I have found, your recommended settings of 20P/100S did not work at all. Perhaps you're basing that on a much more powerful laser?

I also tried 100% and decreasing the speed, which again didn't produce much difference!

Good analysis though, I hadn't noticed the entry points. How do I adjust tickle settings in JC 10.3?

[Dan Kozakewycz]

Scott, settings were 333dpi, 100P/100S, DPI 1000, correction 20.

[Ross Moshinsky]

Increase to 500 DPI. Speed up the laser 5%.

[Dan Kozakewycz]

How do you mean, it's already at 100%?

[Ross Moshinsky]

How do you mean, it's already at 100%?

It's a rule of thumb. If you can't speed up, then you use less power. Same idea.

[Dan Hintz]

Hi Dan

I know you're an advocate of using low power on anodised aluminium, but I did a test ramping down the power from 100% and 70-100% produced much the same response, 40-70% produced varying (darkening) shades of silver and anything below 40% produced absolutely no mark whatsoever. This material needs quite a lot of power to produce a decent mark I have found, your recommended settings of 20P/100S did not work at all. Perhaps you're basing that on a much more powerful laser?

I also tried 100% and decreasing the speed, which again didn't produce much difference!

Good analysis though, I hadn't noticed the entry points. How do I adjust tickle settings in JC 10.3?

I never provided you with any initial settings, so I'm not sure where you got the 20P/100S settings from (it's what I used on my ULS with a cartridge measuring 70W+)... if you pulled those from another thread, then I based those settings upon the power of the system used in that thread (probably mine). We don't know what machine you have (and therefore the max raster speed) or what power cartridge you're working with, so we can't suggest appropriate power/speed settings. If you're working with a 140ips Trotec Speedy with a 60W cartridge, I'd suggest something in the area of 40P/100S.

You're at 333dpi, which has significant overlap on a 2" lens and should be okay for simple shapes like the square, but for high-definition images I'll typically use 500 dpi (or thereabouts).

[Scott Shepherd]

Scott, settings were 333dpi, 100P/100S, DPI 1000, correction 20.

Correct should be at zero for rastering. I'd also do the 500 dpi. Your wattage is a little less than ours, so I'd guess that you'd be at 500dpi, 70% power, 100% speed, and 1000 PPI.

Correction used to be for vector only, so there was a default value in that field. In 10.2, they made it have an impact on rastering, and it's generally a value you want at 0, unless you are having specific issues where you need to bump it up, but I'd start at 0.

Don't worry about the tickle for now. Let's get you engraving with the right settings before you start messing with anything else.

[Dan Kozakewycz]

The correction factor was actually set by the Trotec engineer when he was here setting it up. In honesty, I don't know what it does, but as he recommended it, I have left it as is!

[Dan Kozakewycz]

Sorry, I picked up 20P/100S from another thread, yes. Mine is a 40w Speedy 100 (180cm/s maximum speed I think).

[Scott Shepherd]

The correction factor was actually set by the Trotec engineer when he was here setting it up. In honesty, I don't know what it does, but as he recommended it, I have left it as is!

Dan, the correction factor had a change come to it, so what used to be right is now wrong. Please change it and start there. You should NOT be starting with any value in the correction for rastering. Vectoring? Yes. Rastering? No. It WILL cause engraving quality issues if you have it set too high (or anything at all in some cases).

Please try it at 0 and if you believe it makes something worse, then simply change it back. Or, better yet, copy that material, name it something else like "experimenting" and then change it to zero in that one so you can always go back to what he set it at.

This change causes me headaches. With a value in there, it can mess up how text (or anything else) engraves and since it defaulted with a value in it (which it did nothing in the past), now it's default is set to a value, so it messes things up by DEFAULT. They need to change that default value to zero since they changed it's function. It's a bug, in my opinion, that needs to be corrected.

[Brian R Cain]

I was told by a ULS technical guy who knew his stuff that banding on anodised aluminium is caused by the beam reflecting back and causing interfernce. Most noticeable when engraving large areas. The suggestion was made that to overcome this, slightly angle the workpiece. Probably a few sheets of paper under one side would be enough. I have to say I didn't follow this up at the time so can't speak with any authority about it, however in a different instance there was a machine we had that was exclusively being used for vector marking steel using HPDFO where it developed a random fault and occasionally during a job would stop marking. I eventually tracked the problem down to the lens coating being damaged by spatter off the material. A new lens cured the problem and I can only conclued that reflections from the material would occasionally be sufficiently out of phase to reduce the beam power.

As someone said earlier, this issue crops up from time to time without an adequate resolution, so it might be worth trying what the ULS guy suggested.

[Dan Hintz]

I was told by a ULS technical guy who knew his stuff that banding on anodised aluminium is caused by the beam reflecting back and causing interfernce. Most noticeable when engraving large areas. The suggestion was made that to overcome this, slightly angle the workpiece. Probably a few sheets of paper under one side would be enough. I have to say I didn't follow this up at the time so can't speak with any authority about it, however in a different instance there was a machine we had that was exclusively being used for vector marking steel using HPDFO where it developed a random fault and occasionally during a job would stop marking. I eventually tracked the problem down to the lens coating being damaged by spatter off the material. A new lens cured the problem and I can only conclued that reflections from the material would occasionally be sufficiently out of phase to reduce the beam power.

As someone said earlier, this issue crops up from time to time without an adequate resolution, so it might be worth trying what the ULS guy suggested.

While it sounds all "scientificy", there so much more going on that this would be lost in the noise (and I have lost my faith in anyone working for a laser manufacturer that calls themselves a technical person). Consider this... a few pieces of paper on one end would be a few hundred micrometers. I guarantee the tables on a 24x36 machine are not ground to micrometer-level accuracy to make those pieces of paper amount to a hill of beans. If it mattered, the interference would then vary many many times over a large piece (considering the wavelength of a CO2 laser is 10 micrometers and you're varying the height from 0 at one end to hundreds of micrometers at the other), so you get waves of interference over the entire item. Then try and keep the items moving all over the place within that same micrometer-level accuracy... mirrors, lenses, axes, etc. You can practically see them shudder around as the carriage zips back and forth.

No, I can't believe interference has anything whatsoever to do with problems like this...

[Scott Shepherd]

Any luck Dan? Just as a point of reference, the correction on rastering increases the power at the ends of engraving to compensate for the slow down and ramp up of the stroke. That would mean a value of 20 would put more power at the left and right edge, and leave less power in the middle, which is where you are having the issue (the middle not engraving as thoroughly as the ends). That's why I'm telling you to change that value to zero. It essentially over powers the edges a little to compensate for the ramp up and down in speed. It's not needed often and I'd guess it'd almost never be something you'd use on things like anodized aluminum, but I suppose some circumstance could show up that would need it, but in general, that's not needed on anodized aluminum.

Having a value in that field can make things like smaller text look fat on the ends of travel and the text in the center will look sharp and crisp.

It's a feature that's rarely used for me and it's one of those features you shouldn't use unless you're having issues that require it to correct the issue.

[Brian R Cain]

While it sounds all "scientificy", there so much more going on that this would be lost in the noise (and I have lost my faith in anyone working for a laser manufacturer that calls themselves a technical person). Consider this... a few pieces of paper on one end would be a few hundred micrometers. I guarantee the tables on a 24x36 machine are not ground to micrometer-level accuracy to make those pieces of paper amount to a hill of beans. If it mattered, the interference would then vary many many times over a large piece (considering the wavelength of a CO2 laser is 10 micrometers and you're varying the height from 0 at one end to hundreds of micrometers at the other), so you get waves of interference over the entire item. Then try and keep the items moving all over the place within that same micrometer-level accuracy... mirrors, lenses, axes, etc. You can practically see them shudder around as the carriage zips back and forth.

No, I can't believe interference has anything whatsoever to do with problems like this...

I hear where you're coming from, Dan, but something is physically causing it and it isn't unique to any particular laser. The regularity of the banding reminds me of the sound you get when plucking a pair of strings on a 12 string guitar when they're not quite in tune. I'm refering to the lower-pitched wow-wow-wow noise they make on top of the tone the stings make. If you looked at the signal from these on an osciloscope, what do you think you'd see? Something similar to the banding?

Whilst I appreciate that the technical guys laser manufacturers employ will sometimes be evasive of telling the truth about issues with the machines, and it isn't something unique to the world of lasers, the guy I spoke to was as straight as a die and would answer my questions honestly or say he frankly didn't know just then, but would find out. Never had him fail me.

His suggestion of angling the work to avoid the issue made sense. The bit about the paper was mine, hoping to avoid discussions about focus and so on. The bottom line though is there has to be a rational explanation to the matter and this was the best I've heard.

[Richard Rumancik]

In the initial post, Dan Kozakewycz called the problem he was having as "vertical banding". When we talk about banding it usually refers to horizontal streaks which appear lighter. I don't know if there is an official name for vertical streaks but I suppose "vertical banding" is as good as any for the moment - but people should not confuse the two phenomena.

Brian, was the ULS rep talking about vertical banding or horizontal banding when he made those comments? If someone says banding without qualification I would automatically think "horizontal".

Dan K, I would suggest that you look at mechanical reasons for the vertical streaks. That would include belt tension, bearings, debris on the rails, debris stuck in toothed pulleys or belts, a bad x motor bearing, loose pulley, loose optic . . . maybe others?

It is possible that you might be able to hide some of the problem (if you can't find a mechanical source) by changing your solid black fill to something slightly less e.g. 90% black or 95% black. This will cause a few black specs to appear in the solid white areas of the aluminum, but that probably would not be an issue if it reduces the vertical streaks. I can't say it is the ultimate solution as I suspect a mechanical issue, but it might alleviate the immediate problem.

[Dan Kozakewycz]

Hi Richard.

The machine is virtually brand new, it's probably got less than 10 hours use on it since the Trotec engineer was here setting it all up, and most of that time has been on anodised aluminium so very low output in terms of debris etc.

The banding still appears even on heavily dithered light grey fills! :(

At the moment my best fix when it is an issue is to increase DPI and defocus the lens to overlap the lines. Still some slight banding noticeable but only close up.

[Scott Shepherd]

The banding still appears even on heavily dithered light grey fills! :(

At the moment my best fix when it is an issue is to increase DPI and defocus the lens to overlap the lines. Still some slight banding noticeable but only close up.

Dan, have you tried it with the correction changed? Also, please post your settings. We can't help you without knowing that information.

[Dan Kozakewycz]

I've been to busy have a play with the correction and check the banding again the last few days.

At the moment, I've kept the correction the same at 20 as I know it produces nice results on my own products and being mostly line artwork, any banding is not an issue.

When I get some time I will try changing the correction and see if that fixes it.

I'll make sure I post settings on any further questions. I think (without being at the laser) the settings for this were in the region of 80-100P/90-100S and 1000 PPI. I was varying the power and speed and they didn't have much effect.

[Scott Shepherd]

Note- you already posted the settings, I forgot you did that.

I'd be in the 500 DPI, 70-80% power (for your machine), 100% speed, 500 PPI, Correction 0, High Quality On.

[Dan Kozakewycz]

OK just got these two, both 65P/100S, 1000PPI 600DPI and HQ, but the whiter one is 0 correction and the golder one with banding is with correction at 20.

http://img.photobucket.com/albums/v314/Quicksilver4000/BF4F442A-42B2-45DD-8392-79DDD7FF8AE8_zpsnn6js4bj.jpg

I'm pleased with the difference, thanks for the tip on that one!

I was under the assumption that correction only affected the accelerating and decelerating parts of the motion. Perhaps it is changing it's rate of velocity over a longer distance than I am expecting?

[Dan Hintz]

I hear where you're coming from, Dan, but something is physically causing it and it isn't unique to any particular laser. The regularity of the banding reminds me of the sound you get when plucking a pair of strings on a 12 string guitar when they're not quite in tune. I'm refering to the lower-pitched wow-wow-wow noise they make on top of the tone the stings make. If you looked at the signal from these on an osciloscope, what do you think you'd see? Something similar to the banding?

Whilst I appreciate that the technical guys laser manufacturers employ will sometimes be evasive of telling the truth about issues with the machines, and it isn't something unique to the world of lasers, the guy I spoke to was as straight as a die and would answer my questions honestly or say he frankly didn't know just then, but would find out. Never had him fail me.

His suggestion of angling the work to avoid the issue made sense. The bit about the paper was mine, hoping to avoid discussions about focus and so on. The bottom line though is there has to be a rational explanation to the matter and this was the best I've heard.

Banding can be easily created... engrave a 501-pixel wide image at into a box 1" wide using 500dpi. That'll create one gradual band across the entire image (though you'd likely never see it). Now start increasing the image width pixel by pixel, engraving at 500dpi... every time you hit a specific resonant frequency, you'll see very distinct banding, increasing in number. the bands will fade in and out as you get closer/farther away from that resonance. There's no mystery behind creating banding, the pain is figuring out what is creating the resonance... usually it's a function of some software resonance (like mentioned above or hitting the "beat frequency" of the laser's pulse versus the pixel data) or hardware resonance (movement speed makes a mirror wobble, etc.).

The disappearance of the banding when Dan set the Correction parameter to 0 says it was a software resonance (or software/firmware, if one wants to get particular).

[Scott Shepherd]

OK just got these two, both 65P/100S, 1000PPI 600DPI and HQ, but the whiter one is 0 correction and the golder one with banding is with correction at 20.

I'm pleased with the difference, thanks for the tip on that one!

I was under the assumption that correction only affected the accelerating and decelerating parts of the motion. Perhaps it is changing it's rate of velocity over a longer distance than I am expecting?

Dan, I don't think they like my explanation of what it does, but in my opinion, the correction doesn't change the velocity, it just bumps up the power at the ends of the engraving. What you were seeing is a variation of the power in a small area, where the power is up on the ends, down in the middle, which causes the banding issue. It's really irritating that they have a default value of 10 in there. That default is the default when the correction only controlled corner speed adjustments and it's right for the default to be 10. However, in v 10.2, they change it to have two different functions. One function for vector, one for raster.

I took some time and dialed in a material I was engraving a lot of small text on. I think it was 150-200 of them on a sheet and the text was small. I got it all dialed in and the text was really sharp. Then I did a job like it but a slightly different material, so I wanted to use the same settings. I did it manually but didn't pick up on the fact that the correction was at 10. I engraved a whole sheet and noticed it looked decent, but not as sharp as the last job. It racked my brain for a while and then I noticed it was on 10. I changed it to zero and it got better.

It's just a really bad setting to have set at 10 as default.

Glad you got the issue resolved to your satisfaction.

[Michael Reilly]

I don't know about a change to correction, but my understanding of it was that it was a minimum power threshold. Whether 20 meant it could drop no more than 20% from the setting you are engraving at, or whether 20% was the lowest it could go, I never could determine. It exists because some materials have a threshold at which the material shows a mark. Glass is one, if it doesn't get a minimum amount of power, it won't register at all. But as the laser speeds up and slows down at the beginning and end of each pass, it varies the power to compensate for the change in speed. In those materials, this can lead to losing the edges of your image as the power drops below the threshold. But it can have the opposite effect too, if 20% shows more of a mark than 10%, then when it slows to a point where it would be 10%, it's overheating that area. It sounds like that's what was happening here.

You can also get patterns when using stochastic screening like Stucki, Floyd-steinberg, etc. I don't think those were options for Trotec though. But since they're mathematical random pattern generators, the patterns will repeat. On my Epilog I used to use Stucki all the time, but when I complained about the patterning to Epilog support, they explained that it shouldn't be used unless it's a photo or something with a lot of tonal variation, otherwise such patterns will appear. When I was trained at Vytek, they explained that even in photos, things like faces have similar tones and can show patterning and the solution is to add some noise to the image to break up the pattern (in PhotoGrav.)

Another thing is what Dan was talking about with dot overlap. While it seems like higher resolution is always better, some materials don't benefit from it and it can actually hurt it. If you're trying to do a photo that is composed of dots, the image is produced from the pattern of dots vs no dots. The average spot size for a laser with a 2-2.5" lens is 0.005". If we divide that into 1", that tells us that at 200 dpi, we'd have a row of dots that touch but don't overlap each other. In that case, we could tell if a dot was omitted. But if we double that to 400dpi, now we've packed twice as many dots in and that means they're overlapping 50% with their neighbor. Now if we omit a dot, it's really difficult to tell. So engraving fine text at high resolutions can be beneficial because those close overlapping dots can better fill out the solid letter forms, but if we're looking for detail in a photograph, higher resolution isn't necessarily better.

[Dave Sheldrake]

I was told by a ULS technical guy who knew his stuff that banding on anodised aluminium is caused by the beam reflecting back and causing interfernce.

What the guy is on about is Interposed Phase Stack Cancellation, *technically possible* but VERY hard to do even when working with lab equipment let alone a basically junky laser machine, to try and transpose phases in a lab has to take into account vibration from rooms several yards away when somebody shuts a door let alone when you have a moving gantry running over a workpiece that varies in thickness and distance from the focal point. You are dealing with wavelength distances that on a flat unsupported sheet would be affected by gravity let alone something like a laser machine.

My take? the guy has read the paper "Phase Cancellation Principles" by Prof R G Crooks and is spouting out what he has read in an effort to seem technically proficient to somebody that doesn't understand what they are being told. To anybody that does...it comes across as random rubbish.

Remember an "Expert" only has to know 15% more than the person they are talking to

cheers

Dave

[Dan Kozakewycz]

I think I've managed to get rid of this issue now, at least on the solid fills.

Solution was to turn down the X axis acceleration in the service settings from 9 to 4. This improved the mid section banding but increased it towards the outer edges, so a tweak the correction setting back to 15 saw that evened out. Interestingly, the correction value changed the hue of the entire area, making all of it slightly less white.

Downside is that it's slowed the engraving speed down considerably, but I guess that's a trade off that will need to be made when this level of uniformity is required, but at least solid fills now come out perfect. There does still seem to be some feint banding on photo engraving, but that can be tuned out with a slight defocus.

[Scott Shepherd]

Dan, I'm not convinced you're getting the best advice there. If you're up for it, I'd be happy to try and help you resolve it if you're willing to try some things. Just let me know and we'll take this offline. There is ZERO reason to have to slow that machine down to get solid engraving. If so, then something's wrong with it. That is not normal.

[Michael Reilly]

If you engrave a filled square at 125dpi you will get gaps between the lines. Look at the edges of the box, do the lines line up vertically? Basically you're looking to see if the lines created traveling left to right are in the same position as those created with traveling back the opposite way. Different companies have different names for this, but on Trotec, it's controlled by K1 and Overtook. The manual suggests you engrave a series of rectangles that are spaced across the table and then adjust K1 until all of them are off by roughly the same amount, then use Overtook to adjust them into alignment. So K1 appears to relate to the timing/acceleration and overtook seems to be an offset. Overtook allows you to create different settings for different speeds.

On our current Vytek machine, this is referred to as biDir or bi-directional compensation. I can confirm that it does vary by speed and there is a way to try to put a multiplier in so it can scale the offset as you go faster, but in our case, it's not linear so we just adjust that value as needed when we engrave at different speeds.

While it seems likely that we had a lemon (as most Trotec owners don't have nearly the problems we did, and our machine did travel to multiple tradeshows before we got it), we did have an issue where we could no longer get our K1 set to a useful value. I did find that adjusting the acceleration value made a difference, but as you said, it slowed things considerably. Here is the results of that test:
http://trotecfrustrations.tumblr.com/post/58716173992/it-was-suggested-that-we-should-reduce-the-tickle

The other thing we were getting that we couldn't get an answer to was this, which is extreme but may be similar to the banding you're getting?
http://trotecfrustrations.tumblr.com/post/57226186862/this-is-a-problem-that-i-have-seen-in-my-epilog

The changes seemed to coincide with variations in the amount of engraved vs not engraved areas across the page. So like at the top of the letter "n" when it transitioned from just two vertical bars to the horizontal portion... we'd see a change in the appearance. As I say in my post, this happened on Epilog too, but to much less of a degree. My theory is that it relates to how lasers build power and consume it, and it's up to the software to manage it. We haven't noticed it on our Vytek so apparently it can be addressed in engineering.

[Dan Hintz]

If you engrave a filled square at 125dpi you will get gaps between the lines. Look at the edges of the box, do the lines line up vertically? Basically you're looking to see if the lines created traveling left to right are in the same position as those created with traveling back the opposite way. Different companies have different names for this, but on Trotec, it's controlled by K1 and Overtook. The manual suggests you engrave a series of rectangles that are spaced across the table and then adjust K1 until all of them are off by roughly the same amount, then use Overtook to adjust them into alignment. So K1 appears to relate to the timing/acceleration and overtook seems to be an offset. Overtook allows you to create different settings for different speeds.

If one assumes Trotec is using the universal language of math when describing their system, then K1 would be the overall amplifier gain for their PID control loop (spent a LOT of time tuning those bad boys). Too much gain and you get over shoot, too little and you get undershoot.

[Dan Kozakewycz]

Dan, I'm not convinced you're getting the best advice there. If you're up for it, I'd be happy to try and help you resolve it if you're willing to try some things. Just let me know and we'll take this offline. There is ZERO reason to have to slow that machine down to get solid engraving. If so, then something's wrong with it. That is not normal.

No, I didn't think it was right, maybe there's a better solution but this was the only one I could find given my limited knowledge of the machine and software!

Happy to follow some instructions and see if we can get better results or diagnose a problem, let me know how.

[john passek]

Dan K
I have a speedy 100 60 watt and the default in my correction is 10.
The default setting for Anodized set by the technician is 100 Pwr ,70 Spd ,800 DPI, correction 10. Though I have yet to do very much anodized material these settings seem to work well.
I only post this to give you another set of perameters to think about. Some may think these are way out of the norm and they could very well be right.
Hope you get it figured out and post what results work for you in the end.

[Dan Kozakewycz]

Hi John

Those settings see the anodising completely blasted away on mine, it's not a good finish. I run 65P/100S at 500dpi for my usual work, which is mostly line art (custom technical drawings) so banding is rarely an issue. It's the couple of times I have tried photo engraving on AA (something I am hoping to do more of if I can market it) that the banding becomes an obvious issue.

Here's the test piece I made whilst tuning the settings:

http://img.photobucket.com/albums/v314/Quicksilver4000/Black%20Art%20Graphics/90093F65-9850-456B-A2DA-ECAA8F8A8D8E_zpsrvuigwr6.jpg

Started off at the top with the heavy banding in the middle. I tweaked acceleration (not speed) rate and correction as I moved down the bands and eventually got to the bottom setting, this was the same power/speed settings but with acceleration at 4 instead of 9 default and correction at 50. Not entirely sure it needs to be that high but it was getting late, I had a good result and I left it.

Eventually it put out this using the above settings and a 2mm defocus.

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xap1/t31.0-8/10504808_339481836218419_722511817466821009_o.jpg

https://scontent-a-lhr.xx.fbcdn.net/hphotos-xpa1/t31.0-8/10457681_339481846218418_4836351706465161921_o.jpg

Which I was pleased with, but it does leave me scratching my head over the wonky settings needed to achieve it.

[john passek]

Dan K.
That's great that you're getting it dialed in. Those are looking nice.
I haven't done enough AA to say I have good results yet, I too want to experiment with Photos on different materials so I'll be watching your posts to see how you progress.
I have found that there is a difference in settings between my Epilog and the speedy, I guess because the speedy is faster.

[Kevin Gregerson]

I think the correction piece the above gentleman are talking about is essentially the same as tuning is on the ULS or alignment on the printers checking density and straightness. Basically the process is to find out which produces the best lines etc for your material. It's kind of a pain on equipment that doesn't have any sort of tuning wizard for this type of thing. But it's still possible to do via the process described earlier while still keeping your speed up.

-Kevin

[Scott Shepherd]

The correction isn't like the Image Enhancements on the ULS, it is like the tuning for the "tuning wizard" they use now. But there is no ability to tune each individual material like you can with the Universal through "Image Enhancement" (which I love, by the way). However, Trotec does something differently because you don't run across the need to change things like the Contrast and Density available on the ULS. I don't know what they do to make it not need or have those things, but they do it. I engrave incredibly small, detailed text at 100% speed and it just nails it perfectly. There is no need to tune each material, there's just one master level of tuning and that's it.