Making laser lines darker.

[Steve Strassburg]

I have a project that is a very thin piece of veneer. I want to keep the lines dark and shallow. What would you suggest for settings.

[Tim Mellor]

Just for fun I dropped some scrap on my little 40W laser. 3mm Softwood based ply used in the photos. All Rasters at 400mm/s.

Top Left (partial) 8% single pass
Top Right 12% single pass
Lower right 8% double pass
Separated Tag 15% single pass (light is a bit deceiving it is darker than the 12% one)

If you want to try and reduce the smudging masking tape the surface and bump the power a touch to allow for it. This can be a pain as it then takes weeding and cleanup of the tape but generally is worth it IMO depending on the job.

Depth of the 15% engrave with verniers on it was in the region of 0.24-0.3mm.

Thoughts are a light multipass option is worth a go if you are not to worried about time. It is cleaner and 'seems' shallower. If you are wanting to do vector engraves then absolutely go light and consider rubbing them with pencil to darken or you will most likely cut through at typical speeds.

[Steve Strassburg]

Thanks for the info. Just got my laser and I am slowly learning.

[Tim Mellor]

Whatever you test or try good and bad KEEP RECORDS. I currently have a stash of various samples and tests of all sorts of materials from paper 10mm Ply/Timber and various Acrylics with scribbles on them for power and speeds.

At some stage these will get tabulated and if the Smoothieboard/Lightburn project works out then added to Lightburn's cut library which my current software/hardware doesn't allow.

Providing it is safe to cut try it

[Doug Fisher]

>>If you want to try and reduce the smudging masking tape the surface and bump the power a touch to allow for it.<<

If you are planning to seal the wood surface anyway, applying a coat or two of polyurethane before engraving is often all you need. The smoke just wipes off the polyurethane.

[sebastien laforet]

I have a project that is a very thin piece of veneer. I want to keep the lines dark and shallow. What would you suggest for settings.

there are many parameters you must try.

the dark is made when charring the wood. charring occurs with power AND duration (of the laser on the spot). you may have a lot of power, if the movement is fast enough the wood will be "vaporized" under the laser, but charring will NOT occur.

the focus is important : if the beam is very narrowly focused, chances are that the wood is vaporized, not "burnt". so, you can offset 1mm for example, which make the beam larger. the wood is then just heated by the laser, not instantly destroyed, and the charring occurs.

also, the nature of the wood/paper/cardboard/... is important : some tend to properly vaporize (leaving no or little "dark"), while others generate a lot of stain. i have a nice white cardboard which produces a awful lot of stain (probably due to the glue inside) : it is very easy to have very black engravings.

composite with glue generally generate more stain than "plain" wood.

for example, if you use laser-rubber (for making stamps), you will see the material is destroyed into a fine powder, which does not change color! you can engrave (=carve the form of the stamp) but not mark it!

the ONLY real way, is to make a test grid : you try to engrave the same (small) design many times.. on the horizontal you can play with power (10%, 15%, ..) and vertical you play with speed (150mm/s, 200, ...). at the end you can visually compare the result on the grid, and eventually adjust fine levels of power/speed once you have food a good enough spot.

if you plan to use masking tape to reduce cleaning, you have to do all the test with the masking tape. just 0.1 or 0.2mm of tape can dramatically change the output!

also, be extra careful for the horizontality of your table : just 1mm vertical offset can also change the output. once you have the correct setting, try it in each corner + center of your working space.

[Steve Strassburg]

Thanks for all the info. I made one mistake with all my testing. I didn't keep track of settings for all my tests. So, I broke rule #1. Oh well, live and learn.

[Doug Fisher]

I have started creating a Word document containing notes and results for each new type of laser cutting or engraving substrate I attempt. Include all settings tried, what worked and didn't work, plus a few succinct but sufficiently detailed comments why. It is so helpful when you come back a days, weeks or months later. To be efficient, I usually type in notes while the laser is cutting/engraving a test matrix or run of parts. It is just too easy to forget the important little nuances you learn during a testing session. Additionally, when I run across a helpful note in the forums that pertain to working with that substrate, I will cut and paste the text plus forum link into my Word document.

Save the file to a file folder in the cloud so that you can seamlessly access this information at your computer next to your laser, your main computer in your office, your laptop when you are visiting a fellow laser user or hackerspace, etc.

[Gene Uselman]

Whenever I work with a new material I try to do at least the cut and engrave files in the zip below. The files say Bodor 100W but they are not specific to any laser. These were adapted from Boss laser test files so that they would take up less space for keeping the samples. Delete any power levels that are over what your machine should safely use. You could write the speed, etc. so that you have a good record.

Cut-Engrave tests.jpg

Cut_Test_Files Bodor 100w.zip

[Pete Cyr]

I lacquer most of the stuff I laser and use brown liquid shoe polish to darken the lines.
After the board is lacquered it pretty much is impervious to the polish - -I use the KIWI in a bottle, dab and smear, wipe off