Laser cutting of plywood

First, not so much about a specific design, but about laser cutting in general.

❗ Note: what follows is a mix of theory and personal insights.
To jump straight to the design → scroll down. ⏩

Earlier, I was actively into laser cutting until I got a 3D printer. At that time, CO2 gas lasers were popular. I built my own laser cutter, with a working area of 900mm x 600mm and a power of 40W. The laser tube was chosen not based on budget but on length. For example, an 80W laser has a tube length of 1600mm, but later they started making them shorter—the length was compensated by increasing the diameter.

A bit of boring but simplified theory: Such lasers require high voltage, and the tube itself needs circulating coolant. Before the laser hits the material, it reflects 3 times (not counting reflections inside the tube itself) off mirrors and passes through a focusing lens on the carriage. Each mirror was mounted on its own moving axis (except the first one). All optics and belts require regular cleaning. Solid-state lasers (which are now widely used) eliminate this optics since the laser is directly on the carriage—a big advantage. However, fumes remain an issue in both cases, so good ventilation is necessary.

Now, back to 3D printing. When Bambu Lab entered the market with their 3D printers, they greatly simplified the 3D printing process. New users no longer needed prior experience or had to perform lab-like calibration tasks — it’s like replacing chemistry class 🤓 flasks and reagents with a simple ‘press the button’ manual 🙌.

I think those who worked with lasers before were a bit confused by Bambu's H2D announcement, which includes a laser version. Laser engraving/cutting is a rather messy process compared to 3D printing, and as you understand, the mechanical components and work chamber are shared between both functions in this model. I'm sure this printer has many cool laser-related features, but so far I don't see a 'convenience revolution' - the target audience is enthusiasts.

If people build 3D printing farms from printers, that won’t work with the H2D laser. The working area is the key here. Six 30mm x 30mm plywood sheets, as suggested by Bambu, are like six 30g PLA spools for 3D printing. For example, usually for my needs, I bought a dozen 3mm plywood sheets sized 1525x1525 mm.

If you're not familiar with this technology, be prepared for post-processing of the model. There's no equivalent of 'print-in-place' like in 3D printing (let alone an analog of 'flexible') when it comes to laser cutting—unless you count engraving on an existing object.

By the way, about plywood quality—the info you can read in Bambu’s documentation isn’t just marketing (if you’re interested, you can look up plywood grades and classes). If you cheap out on plywood quality, you’ll make up for it with wasted time and frustration during cutting.

I have several laser cutting designs I want to publish. In my archive, I found a design that I'm adapting for 3D printing later. Conversely, I have a 3D model for printing that can be adapted for laser cutting.

I wanted to cut this design on my Snapmaker 2.0, but my version has just a 1.6W laser 🕯️. You could theoretically cut plywood with it, but it would take many passes - questionable 'advertising' of the machine's capabilities 😂.

⏩ Let's start with a simple design - Heart Box 💗

https://makerworld.com/en/models/1496230-heart-box#profileId-1566795

By the way, the flexible wall design elements actually migrated to 3D printing from laser cutting technology.

For this project, you'll need a 3mm thick plywood sheet.

As you can see here, the lines are grouped by different colors: some indicate engraving, others cutting.

Laser engraving takes longer than laser cutting. However, when compared to 3D printing, it's still a relatively fast process overall.

Now you have the remaining warm parts 🔥

Use PVA glue to assemble them 💧.

Start with the lid. Glue the small heart on the back side; the outer part (a separate component) will act as a template for this step.

Next, assemble the box itself. 
Connect the 4 parts together as shown below, 

and carefully insert the resulting "wings" so the heart doesn't fly away 💓.

If desired, clamp the assembly with a clamp and let it dry.

The walls maintain strength when bent along their intended plane, but avoid stretching or twisting them.

After the glue dries, you can sand down the slightly protruding parts with sandpaper—ideally using a power tool. Then, finish with a finer grit. The main thing is not to overdo it and avoid sanding off the engraving.

Once the surface is smooth enough for your liking, apply wax to enhance the wood grain and darken the engraving. I chose quite dark wax - could have taken a lighter one.

After this, you can polish the surface again to achieve a pleasant shine 🌟

🍬🍬🍬

Originally, the design used four 5×1 mm magnets, but in this case I decided to simplify things and removed them.

As you can see, there’s a lot of post-processing here, but without it your construction won’t look attractive.

Many laser cutting projects are appearing now, but these designs are very familiar to me. Perhaps someone will come up with something fresh and original. Most likely, Makerworld will introduce software to generate laser cutting patterns from 3D models. We might see combined 3D printing + laser cutting/engraving solutions.