I did all my laser cutting at TechShop San Francisco. It was my first attempt and 2 of the 3 boxes that I made worked out but one broke when I tried to bend the lid into place. I tried 3mm MDF, aromatic cedar "laser wood" from www.laserbits.com and birch "laser wood" from the same. The MDF cut and bent perfectly; the cedar burned quite a lot in the cutting (more on that later); the birch cut well but it was too thick to bend.
[Update] I've now improved the design (pictured) and it works perfectly with birch as well as the other woods. See the final step for the updated design files.
- ~3mm laser ply or MDF.
- 6 x 10mm M2 screws and nuts.
- 1 x wireless sensor node (mine is my own design but a friend of mine has written up a very similar one, from which mine is derived)
- 1 x laser cutter, I used a 60W Epilog Helix.
Step 1: Designing the box
Here's how I built up the design (sorry for the lack of screenshots of the working):
- Set the file to be 24inches x 18inches, which is the bed size of the laser cutter I was working with.
- In File > properties add a 1mm grid. (I prefer to work in metric
- Draw a 6 cm square for the base. I didn't worry about details like the screw slots at this stage.
- Draw half-circle for one side and extend down from the ends 1cm to give a flat portion; close the base.
- Calculate the required length for the top = PI * 3 + 2 cm = 11.5cm
- Create a rectangle of that length and 6cm tall.
- Using the grid snap, draw one copy of the living hinge pattern.
- Clone the pattern along the length of the lid.
- Using the path editing tool, refine the shapes, drawing in the pegs and T-slots for the screws. I used a 1mm grid for 90% of the work. For precise pieces like the T-slots, I selected nodes that needed to be "off grid" and manually entered the coordinates.
- Using the grid, draw in 2mm circles for the screw holes. For the antenna hole, I used the snap toolbar to turn on snap to cusp and snap to centre and then let the centre of the circle snap tot he end of the line. Then I used the path tool to edit the line to remove overlap.
- Finally, I added some rounder rectangles to the end piece for air holes and cloned the end piece.
- I was planning to cut different types of wood that have slightly different thicknesses and I didn't want to have to alter the design for each type so I made the pegs stick out past the end of the slots and curved the ends. On a thinner material, they stick out a bit further but no matter.
- I made made the pegs slightly wider than the holes (by 0.2mm) in the design to account for the kerf of the laser beam.