some engraving attempts with the 10watt+ laser

Im using a 10watt+ endurance laser on a Lulzbot TAZ5. After i installed and was able to make the laser work, i started experimenting with lightburn settings and tried to engrave an image on a MDF board. At the beginning i was not getting the results that i wanted, i tried several set ups but none of them gave me the result i was looking for.

these are just a few examples of many failed engravings with grayscale (art by arthur de pins)

As a starting point i was using some of the settings other users were using in their machines, but i was not getting what i wanted, therefore i decided to approach this from a simpler perspective. The purpose of this was to understand how the gray scale works with the laser.

I created a simple gradient without blending the different tones of gray, this way i was able to identify where the laser had to increase or reduce its power (i was worry that my laser was only burning at one constant intensity). knowing that white is 0% and black is 100% (or the value used as max power) i only used 10 different tones from white to black, so i can divide the % max power by 10 and know more less which intensity is each gray.

left one is 0-100% max power, right one 0-50%, both done at 2000 mm/m

Something that i discovered is that when the max power is not at 100% the grayscale is less evident, i’m guessing its because it has a shorter range in between grays to work with. This creates a small issue because if the engraving has to be done on a thin material, the 100% max power is going to cut the material instead of just engraving it, something to consider when deciding to engrave thin materials.

I decided to leave the max power to 100% and play only with the speeds (the mdf is 20mm thick, so i didn’t worry about the laser cutting through the material). DPI is set to 50 so each line is separated from each other to avoid the burning to become a big spot. Angle is 0º so the line is parallel to the gradient.

I found out that my first mistake was that i was using the laser at a higher speed, even though many other users were getting good results going faster. After engraving at 5 different speeds and comparing the results, was time to change the angle of the scans, that way the laser had to change intensity during each scan.

I used the same power, DPI and speeds as my test before, but changed the angle to 90º, this way the laser had to go perpendicular to the gradient and during each scan change its intensity. the photos don’t show fine details of the engravings but the first tests were more successful. In both tests the speeds between 1000-1500 seem to work better. I still don’t know how to avoid the darker burn when the laser finishes a pass and starts the new one (the darker edge).

Rarely the gray scale is going to be this simple therefore i decided to engrave an image. Knowing now that the speeds were too fast for my set up, i applied the speeds that worked better in the last couple tests. I chose an image that had fewer white spots so the laser had to be “on” most of the time.

I made this image a few years back for a skate board design

I grabbed the original image, then converted it to grayscale and finally to bitmap. In my very first attempts i discovered that to get better results using other setting than grayscale in lightburn, the image has to be converted to bitmap.

Did a couple of tests at 1000mm/m and 1500 mm/m but the gray scale still was not as i wanted to be, so i decided to try the jarvis setting on lightburn to compare both. I liked it better than the grayscale, i decided to do more tests with it and with other settings in lightburn.

the one on the left is jarvis, on the middle is dither and on the right is newsprint. I liked the aesthetics of these last ones.

Until i find a result that i like with the grayscale setting, i’m going to use jarvis or newsprint.

Installing and running a 10watt+ endurance laser

As a digital fabricator and jeweler for the past five years, i had never really worked with laser engraving or ever liked the burn edges aesthetic. I had read about these diode lasers and decided to try it out of curiosity. I was impressed with the capabilities of the endurance lasers, specially the ability to engrave metals, which was the main reason i purchased one. I also had never had to deal with DIY machines or had to mess with coding and programing.

I have a Lulzbot TAZ5 and a SharkHD CNC machine, so before receiving the laser i had to decide which machine i was going to use for the laser. The shark had the appealing of the working bed size but was a little bit more complicated to install the laser (i got that impression after reading the endurance laser facebook group and their blog on their website). Then again, never had to deal with DIY machines and their programing so it might be just me. So i decided that i was going to use the TAZ5. I read the instructions on the endurance laser web site (instructions here!) looked easy, printed the part that i thought I was going to need to mount the laser to the extruder but i was wrong.

mounting the laser to the printer

When i received the laser i realized that the 10watt+ laser was bigger than the one in the instructions -way bigger, and installing it with the extruder might be too heavy for the TAZ5. so I grab the .stl file of the extruder base and modified to fit the laser.

the left one is the original base for the extruder, the top one is the piece from the instructions i thought i was going to use, right one is my simple adaptation
back of the laser, it uses 3M screws
had to use some nuts to compensate for the nuts on the laser
the laser mounted to the base, the screws had to be flush with the back so it can fit on the printer

Following the instructions i was happy to learn that my printer already had the firmware needed for the laser to work, so i didn’t have to modify anything. The installation process was very simple (i linked the instructions above), connected the red and black wire and basically i was done. I put the laser on the printer, and without realizing it before, i positioned the laser on the base exactly where the laser would not obstruct the hole for the screw that goes to the printer mount (pic below), happy accident!!

turning it on for the first time

So after checking everything was connected and ready to go, all excited i turned on the printer and…

i panicked for a little bit, then i started searching for the reason why this happened and found out that the printer (because of the firmware or something else, still don’t know exactly what) does not work if there is no extruder installed. I didn’t want to put the extruder on because of the weight, so i started searching how to modified the firmware or any code to make the printer work without the extruder, didn’t find anything. After a couple days without finding a solution and got close to giving up, i remembered that i had an old extruder that a couple years ago i had ruined while trying to modify it. Without removing the laser i connected the extruder and sure enough, the printer worked, repetier recognized the laser and was able to move the XYZ axes of the printer. but again i didn’t want to put the extruder on, so i started cutting parts of the extruder (keeping in mind that the error was the temperature on the extruder: E1 Err: MINTEMP) and just left the temperature sensors connected.

these cables are not connected to the laser, just to the printer

Not only did this helped bypass the error and make the printer work, but because of this, when i want to 3D print something i just need to swap the extruder or the laser, no need to flash the firmware every time or change anything else. I know this is not a real solution, because not everyone have a spare extruder that they can dismantle, but in my particular case, it worked.

focusing

According to this video, the distance to focus the laser is between 2cm to 10cm, but recommends to be at 7.5cm, i put the laser around that height from the table and tried to focus, but silly me, i did it in top of the glass bed of the printer and burned it.

So i got an aluminum plate to cover the bed and attached it to the printer with a couple binder clips, also i created a file where the laser only traces a line along the X axis, and put a tape on the plate so i know how to align my material and it can be square with the laser.

air assist

I did a little research about the air assist, and how it is supposed to work and found out that the air must hit where the laser is burning to help keep the cuts clean and to “increase” the power of the laser. At the height that i have the laser the little copper tube was not pointing to the end of the laser beam, but a little above it, so i made a tube trying to mimic the one in this video where it explains the air assist (hoping it has the same result in the diode laser). I 3D printed it, then attached it to the lens.

When i turned on the pump it was really quiet. but when i attached the plastic hose provided in the kit, it started making a loud noise, i guess because of how small the diameter of the hose is. so i put a slight bigger hose and the noise was reduced.

hose comparison

safety

As for safety measurements, i installed a duct fan in top of the enclosure i made for the printer, printed a 4 in duct intake from thingiverse, and put some duct that for now goes to the outside by the door (i hope i can later make a hole in the wall and install it properly) .

I purchased a couple of 24×12 laser shielding acrylics from J Tech Photonics, they claim that this acrylic will filtrate from 250nm to 520nm. I made a couple doors to close the enclosure, this way the duct fan would work better and the fumes would go to the outside and no inside my workshop and it will protect my eyes.

software

As software goes, i follow the recommendations of some of the other endurance lasers users and installed inkscape and the endurance laser extension, but had some problems with it and after a few days without any answer, i decided to move onto lightburn, and i was able to start engraving, i’m still trying to figure it out how the laser works and all the parameters that i need to set depending on the material and what i want to engrave. but so far, i got the best results if the image is converted to bitmap and using the “jarvis” setting on lightburn, if i try to use the gray scaling even at 5% max power i get burned images and not a good gray scaling.

these are just a few tests i did on MDF, after several failed attempts to get the grayscale going, i change the image (in red circle, artist shane hunt the other image is by arthur de pins) converted it to bitmap and use the jarvis setting on lightburn, got a good result.

I’m still testing the grayscale and learning more about the laser, but for now i think i can say that i’m really happy with it. my only complain is that the fan that is attached to the laser has its blades exposed, which caused me to break a couple blades by accident. I’ve seen other photos of other 10watt+ lasers and the fans’ blades are not as exposed, so i just have to be more careful with it.