By Tim Bancroft
I needed to build a modular baseboard for a model railway, to replace previous attempts
- Around 1200 x 600mm
- Ability to be dismantled and moved by one person
- Made out of wood
- Simple construction
- Repeatable & easy to manufacture
- Contains all necessary electronics / point motors etc.
- Not too expensive
Build / Design Log
After being inducted to use the Trotec Speedy 300 at South London Makerspace, I had the ability to precisely cut wood. I thought this would be a good excuse to design and build such a module.
I had not used any CAD programs before, so looked at what was free. All programs had a rather large learning curve but I chose SketchUp. After what seemed like an age trying to figure out how to get SketchUp to play ball I started to figure it out. The laser cutter has a bed of 726 x 432mm so to make 1200mm long sections there will need to be a join. Also one of the main sizes that laser Plywood comes in in 400 x 600mm.
The first bit to design was the end wall. This needs to mate up against another unit so is (like all the parts) symmetrical.
Then the side walls: Since each board will need four sides, I needed a method of joining them. I went for a dovetail arrangement (the top board also spanned the join to give more reinforcement).
Much like drawing an owl, the design was then complete.
I needed to get a 2D SVG out of SketchUp. I used the modified FlightsOfIdeas plug-in to do this, which can be found at github and installed manually into SketchUp.
This meant that I had a number of SVG files for each component. I placed these flat and merged them to maximise the usage of the laser ply in Inkscape.
This meant that out of 11-12 400x600mm boards i could make two 1200 x 600mm baseboards.
Once I had the SVG files, they were sent to the laser cutter. This is done simply by pressing Control + P and choosing the laser cutter as a printer.
You have to go through some set up: Thickness of material, speed and number of cuts etc. After sending all of these to the printer, the parts were cut.
Unfortunately I did not get any videos / images of the laser cutter cutting, however here are the results of the cut parts put together to test the fit.
Once all the parts had been completed, the modules were glued and left to go off. A completed baseboard can be seen below.
Both units are 1.2m long by 0.6m wide. The dovetail joints are reinforced with a wood square glued behind it.
The underside of the baseboard was designed to hold all of the electronic modules. Some of these were installed along with the USB / to MERG CBus control module.
The baseboards fit well together and were much more precise then my previous attempts. It took a little while to get the tolerances correct, as you have to take into account the kerf of the laser cutting beam. SketchUp has quite a steep learning curve but I found it great for visualising the parts and how they would all fit together.
The next design will need a curved section so this should be an interesting challenge.