Engraving test file

[Graham Taylor]

I've had my Trotec for a couple of months now and have been using it mainly for cutting our own stencils and a few signs from acrylic and MDF. However, I've had a few enquiries about doing some engraving so I now seriously need to start to get my head around the engraving side and will be testing out some new materials - anodised aluminium, some fancy wood (not just MDF or ply) and some granite.

With this in mind do you guys have a standard test file that you use when trying to get the optimum power/speed settings for a engraving onto a new material? If so, what do you include in it?

I was thinking of a couple of different fonts at different sizes, various line weights and shapes and a couple of images - is this about right or total over kill? Do you guys just use an image that you know works well on most materials and a couple of line weights?

I am assuming that it is individual choice etc, and that there isnt an industry standard file due to the amount of different machines and materials available.

As usual, thanks for any help and advice given.

Cheers,

Graham

[Keith Winter]

I normally just make a small 1x1" or 2x2" snipet of what I'll be engraving to minimize waste, testing it over and over until I get the settings right.

[Keith Colson]

Engraving can get quite tricky on wood if you want some really nice results. e.g. typically I engrave wood 8mm out of focus and slow speed to get a really nice dark burn. But you can only do this if the artwork does not have fine detail. Also some engraves require shading which makes things fun too. You just need to get a few materials and have a play. Most machines let you tune out the backlash on the belts if you need precision engraving too. I like to engrave very small concentric circles to test that.

Settings change things a lot, here are some things to consider
Speed - slower gets more burn
Power - sets your depth
Tuning - compensates for backlash
Focus needs good calibration for fine work.
Focus - out of focus for extra burn and hides raster lines
Resolution - higher resolution = slower engrave, higher price
Nozzle - some engraving requires the nozzle be removed
Masking - some engravings need to be clean so the work needs to be masked.

Lots of stuff to work out. I document my successes so I can repeat them with little effort. Basically your test pattern will be different for what you are trying to tune.

Cheers
Keith

[Graham Taylor]

Thanks gents, it seems that I have a lot to think about and practice

[Frank barry]

Graham
Keep it simple to start with as its best take each step and learn as you go

good luck Frank

[Mike Null]

When you're testing fonts be sure to test a few script fonts. They tend to be more bothersome than standard fonts because of the fine lines. When you test the script fonts vary the dpi to see which works best.

[Scott Shepherd]

Just remember, you can change the power and speed when it's running, so pick a starting place, as it's engraving, keep changing it until it's where you want, then save those to the material settings (it's a save icon next to the power setting boxes).

[Mike Audleman]

I have a few test files. All of these test files are stored in my laser's memory.

1. Line Power
This prints a 2" x 3" "card" that has cut lines stepping from 10% to 100% in 10% steps with the speed set to default so it can be controlled by the panel. This is used to find the power and speed combo on a new material that will do a clean cut. I can run it right from the printer panel and since the speed is controlled by the panel, its universal.

2. Line Speed
Identical to #1 except that the speeds are stepped from 10-100, and a second one stepped from 100-200 both stepped by 10mm/s. The power is set to default so its panel controlled. Same use as #1.

3. Dot Line Power
Same as #1 but the lines are dotted. Used to test perforations on a new material.

4. Raster Power
This prints a 2" x 3" card that has small boxes stepped in power from 10 to 100% with the speed set to default. This is used on a new material to test engrave depths or ability to remove anodizing/coating.

5. Raster Font
This prints "Wolfie" out in raster mode on a a 2" x 3" card. Speed is stepped from 100 to 300 in 50mm/s steps on one and 300 to 500 (max speed on my laser) on the second. Power controlled by panel. Used to see how deep fonts will engrave or how well it removes anodizing/coating. I usually use this after #4 gets me in the ballpark.

6. Raster Font 2
Prints "Wolfie" in raster mode. Both speed and power are controlled by panel. Used to fine tune after #4 and #5 above.

When I get a new material, I usually run these test cards on it. Obviously only the ones that are appropriate, like cut tests on aluminum are skipped. On the back I write the material (if its not obvious) as well as any default panel settings (ie speed for #1 or power for #2). The cards are cut out (when possible, ie not so much for aluminum but fine for wood/plastics) and have a small hole in one corner so I can clip them to a keychain I keep near the laser as a reference book. I usually run the tests twice, once with masking tape, once with a clear coat paint or nothing depending on which is most applicable to the material.

[Jiten Patel]

I did not know that Scott - what do you do, simply change the figures for both rastering and cutting on the fly?

[Mike Audleman]

I did not know that Scott - what do you do, simply change the figures for both rastering and cutting on the fly?

Yes. You can press the pause button, alter the power or speed and then press resume. Mine reverts to the previous settings after its done so write down or remember what you changed it to.

I used to use that method but I found it better to spend a few minutes printing out test cards for reference. gets me pretty close to start with. Each image rasters a bit different but I don't do much with images. Most of my stuff is font, text or vector shaped based instead of photographic.

[Scott Shepherd]

I did not know that Scott - what do you do, simply change the figures for both rastering and cutting on the fly?

Jit, you don't have to hit pause. See the graphic below. Unfortunately, it only works for red and black (don't get me started, I asked for that to work for all colors 2 years ago...) , but all you do is go to this area, enter your new settings, hit the enter button or tab over to the next location. If you see it's cutting good there, then just hit the disc button on the right and it'll save those settings to that material.

Click on this image to enlarge it.
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[Mike Audleman]

Scott, some printers won't accept changes to settings while they are running a job. Mine won't. At least I have never gotten it to do so. It does fine if I press pause, change, and then un-pause.

[Scott Shepherd]

I understand Mike, but Graham was asking about it on his Trotec, so I wanted to make sure he knew that it was possible. Most people don't even know you can change things on the fly, so that's why I brought it up.

[Keith Winter]

Mike to clarify this is Job Control exclusive to Trotec Scott is talking about. Your software will be different. OP Graham appears to have a Trotec so he should have it.

[Dee Gallo]

Graham, to answer your original question, I use a couple of test files when I try out a new substrate. This combines a photo and some text (usually the settings). This accomplishes two things: I have a record of what worked (or failed) and eliminates the variable of using different photos so you know what to expect. These samples, along with my notebook full of settings collected over the years, keep me from having to rely on my memory or wasting a lot of time testing settings. The materials you see here are ivory piano key, cast acrylic, coil stock (similar to anodized alum), LaserTile, rosewood piano finish.

When I first started out 10 years ago, this procedure was very helpful. I still refer to my notebook and update it continuously as new materials are introduced. It's also helpful to write your settings on the document itself (outside the printing area).

Hope this helps, dee

[Bill George]

My ULS came with a section in the Owners manual with about 20 pages or so of suggested settings for materials. I have found it be very close. I have it printed out and in the shop, when I cut or engrave something and it needs noted it gets penciled in.

[Roy Sanders]

Okay this was a very helpful one for a new laser user. My Nice-Cut midi laser doesn't have a memory, I wonder if I anymore too. One post talked a bit about focus. is there a way to focus the laser head? or is the focus all in the software. I use CorelDraw x6 and LaserDraw for the machine controls

Thank you

Roy

[Mike Audleman]

Okay this was a very helpful one for a new laser user. My Nice-Cut midi laser doesn't have a memory, I wonder if I anymore too. One post talked a bit about focus. is there a way to focus the laser head? or is the focus all in the software. I use CorelDraw x6 and LaserDraw for the machine controls

Thank you

Roy

I don't know your specific laser, but in general, when we talk about focus, its the focus of the laser beam. This is, for most lasers anyway, controlled by the distance between the surface you are etching/cutting and the lens in the tube. You normally set this by adjusting your Z axis which is usually the bed height. I am sure as a kid you played with a magnifying glass with paper and the sun. Remember how you had to find the right height off the paper for it to burn a fine line? Thats what we are doing with the laser. It has a specific distance from the lens where its at its finest focus point. That is the height above the material you generally set the laser to.

The exception is that sometimes its actually good to adjust the height so its slightly out of focus. This produces a softer spot rather than a fine dot. Great for softening out engraved images and softening font edges. Not so good for cutting in general though.

If your laser has a software controlled bed height (z-axis) then, yes its set in the software. If you have to turn a crank to raise or lower the bed, then no, its done on the machine manually by turning the knob.