Written by Nick Biederman
I have owned and worked with several laser cutters over the last few years. It started with a Full Spectrum Laser at Cincinnati’s public library. Next I bought a K40 laser which lasted about a year before the tube died. When I moved to Columbus I started using the Trotec and Rabbit lasers at The Idea Foundry, and currently teach orientation classes on their Rabbit laser. Most recently I purchased a generic 50 watt laser. All of these lasers are CO2 lasers ranging from 40 to 120 watts. But I’ve never worked with anything like the TwoTrees TOTEM S diode laser.
Diode lasers are very different from CO2 lasers. Instead of having a glass laser tube that generates a beam which is reflected by mirrors to a cutting head and focused by a lens, diode lasers have the laser source mounted directly on the cutting head. Think of them as high-power laser pointers on CNC Etch-a-Sketchs. The power measurement for diode lasers is different too. Diode lasers are measured by the amount of power consumed, while CO2 lasers are measured by the amount of power produced. This makes it difficult to compare the output of diode and CO2 lasers. While the TOTEM S is listed as a 40 watt laser, it features a class IIIb laser source.
This puts the power output in the 5-499 milliwatt range.
The TOTEM S uses a Class IIIb laser source, putting its power output in the 5-499 milliwatt range.
Class IIIb lasers pose a significant eye hazard. Direct or reflected exposure to the beam of light from a IIIb laser can quickly blind you. Longer exposure to diffuse reflections (such as the laser dot on a piece of material being engraved) can also cause eye injury. For this reason, Twotrees includes a pair of green protective glasses and a shield that should be mounted to the laser source. For more information on class IIIb lasers and their potential hazards, check out this page from lasersafetyfacts.com.
A pair of green safety glasses and a red plastic guard are included to help mitigate the danger of the laser.
The TOTEM S laser comes disassembled. Everything is neatly packaged and clearly labeled. Assembly is a straightforward aluminum extrusion and T-nut affair. If you’ve assembled a 3D printer like the Creality Ender series you’re already familiar with the construction. Assembly took me about an hour. The instructions, while mostly pictographic, were easy to follow and understand. The clear labeling and organization of all the parts made it easy to find the components needed for each step.
Everything is well packed and nicely organized, ensuring nothing gets damaged and parts are easy to find when needed.
The TOTEM S works with two different control softwares: laserGRBL and Lightburn. LaserGRBL is free and open source, while Lightburn requires a license. The license is $60, and comes with a year of upgrades. After a year you can continue using Lightburn, but will not be able to update the software. You have the option of renewing your license for $30, which will provide another year of updates. I chose not to renew my license when it expired about 2 years ago, and I don’t feel like I am missing anything. (We’ll get more into laser software next week). I used Lightburn for my first few cuts.
Lightburn and LaserGRBL can both be used to control the laser. I prefer Lightburn.
One problem I quickly discovered is the lack of ventilation. Without an enclosure it’s difficult to exhaust smoke out of the room the laser is running in. I wound up putting mine in a closet with a window and used a fan to vent the room outside. I did some engraving tests, including this whitetail buck. It’s about 3.5” square, and was engraved at 200mm/sec and 100% power. The results are exceptional. The engraving is dark and the lines are crisp.
One of my first real engraving tests produced this very sharp image.
With the success I had on the engraving tests I decided to try cutting some 3mm birch plywood. This presented another issue. Without something underneath the material, the laser will damage the surface it’s sitting on. In my case, that’s the floor of my closet. To combat this, I put the laser on a piece of ¾” thick plywood. Cutting was very slow and charred the front, back, and edges of the plywood being cut. It took 6 passes at 4mm/sec and 100% power or 12 passes at 10 mm/sec and 100% power to cut through 3mm plywood.
The first test cuts were less than stellar. These ½” squares were slow to cut and show lots of charring on the edges, front, and back.
Compared to the engraving tests, the first cut tests were disappointing. However, the material is directly in contact with my protective plywood. This results in some burning on the back of the material and reduces the efficacy of the laser. Many laser cutters use a honeycomb table to help resolve this. Twotrees offers a honeycomb bed specifically for the TOTEM S. I don't have one, so I decided to take the honeycomb from my CO2 laser and run some more test cuts. I also found higher speed and more passes helped reduce charring. The living hinge below was cut in 14 passes at 8mm/sec and 100% power. It’s about 3” square and took just over an hour to cut.
This “living hinge” was made by cutting a series of lines to create a flexible portion of plywood
The TOTEM S laser’s performance surprised me. I’ve always viewed diode lasers as toys, good for engraving and cutting thin materials like paper or cardboard but not up to the task of processing wood, acrylic, or other materials. While the TOTEM S took significantly longer to produce the same results as my 50 watt CO2 laser, it’s definitely capable of processing thin plywood. Unlike a CO2 laser, the TOTEM S does not require an air compressor for air assist or a water pump to cool the tube. This makes the TOTEM S significantly quieter, and I don’t find it distracting to have it running in the same room. There’s no mirrors to align or lenses to clean. It’s much smaller than the most compact CO2 lasers, and has an excellent footprint to cutting area ratio. These features, combined with the low price point, make the TOTEM S a compelling option for hobbyists looking to get into laser cutting or engraving.
But we’re not done with the TOTEM S yet – we have a full month of TOTEM S reviews, comparisons, and use tips coming up!
More TOTEM S guides:
Using LightBurn with the TOTEM S laser
I didn't even realize we sold something like this, so I'm intrigued to see what else we have on the TOTEM S this month.
Submit photos and a description of your PC to our build showcase
See other custom PC builds and get some ideas for what can be done
Services starting at $149.99