Marco Jonsson Project 2: Laser Cutter

Process:

 I decided to make something a little unconventional for my laser cutter project. I lost my glasses case a few months ago and wanted to replace it, but felt that a rectangular prism wouldn't make a good fit. I elected to make a "living hinge" box from a single piece of wood with two small wall cutouts. I am notoriously bad at press fitting parts together, so I wanted to minimize that as much as possible. I learned the method from two different tutorials, with the links provided below.

https://www.youtube.com/watch?v=qLjHWRs-iiI&t=1622s

https://www.youtube.com/watch?v=nt-44j15xeI

 

To begin with, I made a few sketches around the rough shape of an eyeglasses fusion360 file to get a rough feel for the dimensions. I then worked on correctly constraining the wall geometries like shown below. 

I then extruded these into wall segments that I anchored down. It was here that I used the Fusion360 Sheet Metal tool. This section of the software allows you to create "flanges" which can be folded and unfolded when given a rigid plane to rotate around. This was essential to make the folding face for a complete fusion file as well as the DXF files. After some very laborious parameter declarations (see below) and some math to make sure my cuts were correctly spaced to provide the minimum curvature radius for the wood, I was able to import a DXF of a leaf design to mockup the final design.

 

 With the lattice of cuts for the hinge complete, I was able to extrude a 0-thickness surface, then "thicken" it to use it as a cutting body for the base piece. It looks like the picture below right before the cutting operation.

After this operation is done, a bunch of tweaking of components and sketches went into making sure the teeth fit snugly, and the piece would fold on itself correctly. There was a lot I learned about the rule specifications you make in fusion for the "sheet metal" procedures. One of the biggest things was that if you have the incorrect minimum radius of curvature for the material, you end up with edges that aren't flush.

The finalized cut design looks like the following screenshot. I included both the unfolded and folded views.

The final steps of assembly were adding the DXF facial profile sketches to Adobe Illustrator, adding my name tag on the back, and cutting! It came out really well! I had very few joints to press together with a bit of wood glue, and with the use of a few magnets, created a sealing clasp for the case. I included a few pictures of the final result below in the Results !

Result: If you check out my fusion folder, you can see there was more than one iteration of the hinge layout. My final design had literally hundreds of bodies within each subcomponent that made good fusion practices like use of the timeline essential to keep working. I think the final file took me over 8 hours to produce, but the result was worth it! The only disappointment was that some of the cuts were narrow enough to leave a slight burn mark on the slats. If I were to do this again, I might make the spacing marginally larger to allow for a little bit more cooling area for the laser. I gained some very useful knowledge of how to maneuver far more complicated fusion models throughout this process, and learned the importance of isolating separate components to make mistake editing easier. Final Result photos below!

FUSION TIP: If the line you want to select is hidden behind another line, click and hold to pop open a menu showing all the lines your mouse is hovering over. This reduced some major headaches regarding clicking through various layers of sketch lines.

Reflection: Modeling these files was insanely time consuming. I think I may have gone a little overboard on the model complexity, but at the same time I wanted to make something I would be willing to use. Part of my personality requires that if I'm going to do something, that I go all in. This weekend was pretty tough, and I was bummed out about how behind schedule I got with the fabrication, but I'm proud of how well the final result came out, and that the assembly process was so much easier thanks to the extremely over-engineered design :) In the future, I could redo the same process much faster now that I understand the general structure of the living hinge cutting layout, and the functionality of the Sheet Metal Tool in Fusion360. I am probably going to make a few more of these now that the models are made to give away as gifts to family members