Trotec high quality engraving

[Jarami Reid]

Hi folks,

high quality engraving mode giving me headaches here. I'm engraving an anodized aluminum book cover placement matters, consistent mark matters, can't figure out how to get both.

putting a line on either side of the engraving is not gonna work cause the graphic is in the middle of the piece. I don't want the graphic distorted either.

I have a 60 watt laser, anyone with good trotec settings for black anodized aluminum out there? don't have a test piece so any suggestions appreciated, to eliminate some of the risk.

[Dee Gallo]

Jarami,

To register the book cover and design:

1. Place a book sized box with 1 point line over the design and position it so your design is where you want it on the book. Then just fill the box with white and what's underneath will not print.
2. Print the outline of the book on a piece of paper larger than the book cover, using low power/fast speed (such as 20 power/100 sp or whatever relates to Trotec). You can tape it down if you're nervous about the paper moving)
3. Place the book on the outline, re-focus and print ... AFTER you have deleted the white box!

To be extra safe, put some tape over the book and run the job 20 power/100 speed to check for perfect placement. If you are happy with it, run it again full power(without removing the tape). I don't have a 60w or a Trotec, so I can't help you on settings.

cheers, dee

[Richard Rumancik]

Jarami, sometimes I use aluminum foil tape with PS adhesive to protect areas NOT to be engraved. You can also place a piece of masking tape overtop of that, so that you can plot a registration or test mark if needed. By using aluminum tape, even if you make a mistake on power settings the laser cannot penetrate it. Home Depot has 2" wide, not sure where I got the 1" tape. It is usually used for sealing ducts but there may be other applications.

[Jarami Reid]

Hi Dee, Richard,

thanks for the responses.

I should better explain my problem. Trotec has a setting called "high quality engraving" it prevents your mark or engraving from inconsistencies within your mark or engrave. With a word such as "lawyer" the top of the "l" and the bottom of they "y" appear different if your laser only travels to the extent of the mark your making. High quality engraving forces the laser to travel the complete job width regardless of what is actually being marked.

the problem is that High quality engraving distorts your image so your output is not precise. I'm wondering if anyone has a workaround for this problem. I charge based on time - so forcing the laser to travel the complete length of the book by placing lines outside of the cover area may not be the best solution.

[Randy Digby]

I have a Trotec Speedy 100 and engrave many anodized aluminum parts daily. For my 30 watt machine, I run at 100% power, 50% speed at 500 dpi. I do not have to use high quality engraving on the dark anodized parts. In the past I ran some 12" x 16" parts that had vertical lines and the part had text next to the lines in some places and if I did not use high quality, the vertical line would engrave a little differently when there was text on the same engraving position as the line (not sure that makes sense) and the head would have to move a different distance, so I'm familiar with what you are talking about. When I do use high quality, I have never seen any inconsistencies in the engraving. Perhaps you could post a pic of your problem. If you want to talk, PM me and I'll send you back my toll free number.

[Mike Null]

The problem is not likely the HQE mode on your Trotec and in no way does it distort the drawing. It simply moves the carriage completely across the x axis regardless of the size of the engraving. I do not use it as it slows you down considerably.

I am much more inclined to think that your work is moving on the table.

[Jarami Reid]

Hi Randy,

I'm pretty sure you familiar with what I'm talking about. Across the width (x axis) of your engraving do you ever get variation in engraving quality - at the edges of you graphic? If not, I think you may have solved one of my problems. Based on your speed settings (yes i know your machine is different wattage) I think I should be engraving at slower speeds.

I think if you look closely you will notice that the graphics you engrave in high quality mode are slightly out of position?

Hi Mike,

In short - you are mistaken. HQE mode does distort you graphic and on large pieces it is quite noticeable.

[Richard Rumancik]

From your first post it sounded like you wanted to put a line on either side of the graphic to make it plot better. The foil tape idea was just to prevent the vertical boundary line from etching.

The HQE mode sounds like a brute-force method that was developed to solve some motion control issue. By going full width for each pass they guarantee constant velocity and acceleration for each line of the engraving. But to engrave over all that white space is sure to add a lot of time to the job. It is not really a very good solution. However, if it still causes distortion problems something is seriously wrong.

Have you talked to Trotec about it? Can you post an example of the distortion you are referring to?

[Jarami Reid]

Richard - I understand now, you are a lifesaver. Your solution might not solve the Trotec HQE problem, but it will certainly work for this application.

Posting an example is more explanation than needed - In high quality mode the graphic shifts usually in the direction of down and to the right and is slightly squashed along the x-axis. If you ar trying to centre a graphic and your borders are close to your graphic it is noticeable.

I have talked to trotec about it - the conversation is recorded in Sawmill Creeks forum archives.

[Jarami Reid]

The forum detailing my conversation with trotec about can be found if you search -
Trotec raster engraving problems

[Jarami Reid]

Richard,

just wanted to give a sincere thank you. I just re-read your first reply and realize that I should have been able to understand what you were talking about.

So thanks for keeping an eye on the thread and helping a fellow engraver out.

[Mike Null]

Jarami

If your machine distorts the drawing in the HQE mode then the problem is with your machine not with the function. Mine does not distort anything.

If your issue is that you are trying to engrave something against the left ruler and it's fading then slow it down or move the drawing to the right.

When you say "distort" that is different than a ramp up issue and a picture would be helpful.

[Jarami Reid]

Mike check the forum thread that I mentioned in my previous post - there you will see Jon Colley from Trotec Canada talking about this issue. ? .

to test this - take a scrap piece of wood, use a file with a square centred in a circle. Score the circle and engrave the square. now don't move the piece of wood, change your settings to HQE mode and do the same job in the same position.

You are right, I have two different issues a ramp up issue and a distort issue - I need to solve both. HQE would solve the ramp up issue but it creates the distortion issue.

. . . funny how some aluminum tape can solve a problem that a $X0,000 piece of machinery can't! lol.

[Mike Null]

Jarami

I checked the thread and now remember it. I respect Jon's remarks but I still say I didn't get distortion. Of course, as soon as I realized how long it was taking I switched off HQE, never to use it again.

In both posts you were the OP and photos were requested so far you have posted no photos in either thread. They would be very helpful to the folks who are trying to assist you.

[Jarami Reid]

In all politeness Mike,

photo's take time, I don't have an accurate sample on hand, and Richard (on just the second response to my query) solved my problem without a photo.

Have you ran that test yet?

[Mike Null]

Jarami

Thanks for fixing the sig.

I am not going to run the test as I don't use the feature. When I did use it it was for rastering and I noticed no distortion.

[Richard Rumancik]

Jarami, glad to hear the vertical line/alum tape solution will work in this instance. The vertical line solution has been around for a while, but if the lines end up way off the part it adds too much job time. The alum tape just allows one to keep the lines a reasonable distance away from the graphic. Just be careful when doing it . . .

I took a look at the old thread (03-15-2010). I am a bit bothered by (Trotec rep) Jon Colley's explanation about how the word "lawyer" won't engrave properly because of the fact the "l" sticks up above the rest of the characters. To me, the motion control algorithm should accommodate any width of graphic, as that is what the y-axis overtravel is for. It allows for a ramp-up distance so the carriage is at full speed when it hits the first pixel of the "l". So if the ramp up distance is .50" it should overtravel .50, accelerate to max velocity, image the row of pixels for the "l", then ramp down over .50", reverse, and repeat. This should occur regardless of how wide the graphic is at that particular raster line.

Large ramp-up distances are generally bad, as they steal from the maximum available engraving area, and add time. I know some manufacturers have tried to develop motion control algorithms to lay down dots during the ramping period to decrease overtravel. I say, "good luck with that". I'll believe it when I see it. It is hard enough to get a good-quality image when you are in the constant-velocity mode.

But I just get this feeling that there is a bit of an issue with the ramping in the Trotec if it can't plot the word "lawyer" without having problems on the "l" and "y". The HQE option really is not a solution to the problem.

For problem graphics, I can visualize a driver mode whereby you tell the laser to increase overtravel (say from .50" to 1.0"). In effect, it would add an "envelope" around the graphic, but not a full rectangle. This added ramp distance would give the carriage a bit more time to stabilize before it started rastering. It would take a little more time to engrave. But it would not be plotting miles of blank area like HQE does, (and the way ULS does with their "frame rasters" solution, as I understand it.) The "cost" of the extended overtravel mode would be slight increase in time and a reduction in available raster area on the table. Both may be tolerable compromises. Any laser manufacturers want to add this option? It should be a piece of cake to incorporate.

BTW, the vertical line solution is really a poor solution too, as it also forces a lot of white space to be "engraved".

I am having difficulty understanding how the word "distortion" is being used in these 2 threads. In the first thread it seemed evident that there was misalignment between HQE graphics and associated vector pattern. But misalignment and distortion mean two different things to me. So I'm still confused as to what "distortion" is in this context. Jarami, can you please clarify? Do you mean a HQE image will plot in a different spot than a regular image? I would not call that distortion error; I would call it an origin error or alignment error.

[Jarami Reid]

Hey Richard,

When I get a picture of this I'll pm you.

For now I'll say that yes there is an alignment error, but what I've also noticed with larger graphics is that there is also a distortion that takes place. The distortion is almost like an inverse fish eye effect - if that makes sense?

I know this because of multiple botched jobs - in one instance I engraved (in HQE mode) 28 precut, 1" delrin circles with a company logo. I had them set in a row and the middle circles had the logo in the middle but slightly high - the circles to the left ruler had the logos high and to the right, the circles to the right ruler had the logos high and to the left.

I'm not a total noob so pointing out that there could be other variables at play is going to be counter productive!

I've worked hard to get precise and accurate results with my machine, and to eliminate as many variables as possible.

I think it is more a distortion error as opposed to misalignment -and I think like Jon says with larger tables such as mine it is more apparent. For the time being I'm happy to use the aluminum tape, the slight increase in total time/cost makes up for the added trouble of setting the job up.

In Trotecs defense HQE graphics always look really good, and in those instances where the distortion won't be noticed or can be compensated for, I've used it to create some of my most awesome engravings!

[Richard Rumancik]

Jarami - post the picture here - lots of other people want to see it too. That's a really odd situation you are seeing. It's hard to visualize what might be going on to cause that.