RepRap: The Story So Far

When my father and I first embarked on our RepRap journey, there wasn’t a single one in the world that had actually printed anything. Forget cutting edge, this was bleeding edge technology.

Fast forward roughly 5 years: there are working RepRaps all over the world, and we are finally on the brink of joining this club. In the coming weeks I plan to record our experience of “the home-straight”, but first here is a quick summary of how we got here.

Summer 2006: Le Darwin

We first got out hands dirty with the Darwin machine. Dad had discovered the RepRap project through work, and asked if I fancied building one. I’d had a great time previously building a robot from the Real Robots Magazine, one of those “subscribe and get a new part each week” deals, and so agreed straight away. Deciding to focus first on the electronics, we put together our bill of materials and ordered the components. Their arrival coincided with a family holiday to France – what perfect timing, we could assemble the boards without the distraction of any work. This lead to a last minute panic at the airport security checks, where I realised I might have a tough time explaining the electronics in my hand baggage, should the security officers decide to take an interest. Thankfully though, I passed through security without incident.

Building the electronic in France posed other problems, for instance where to buy a USB to Serial cable from? And for that matter, what would it be called in French?  For the most part though we made good progress, completing the boards up to the first or second round of testing. Not bad for two weeks! However progress slowed substantially when we returned home, inevitably. Then before we knew it, I was off to university and so the project was put on the back-burner. I had grand hopes of continuing the build at uni, but it soon became apparent that was unrealistic.

Spring 2010: Darwin Take 2

Back at home after graduating and without a job, Dad decides we should revive the Darwin project. In the intervening period however, the RepRap project has moved on to RepRap mark 2 aka Mendel. After digging out the old instructions for the Darwin electronics and trying in vain to get them working with the new host software, the resounding advice from the RepRap community is to scrap Darwin and start again on the new and improved Mendel.

Summer 2010: Mendel

Here commenceth the Mendel build. The mechanical construction went by without much incident, and we ordered Techzone G3 electronics from across The Pond. We expected the electronics to need assembly and ordered the components too, but were surprised to find them fully assembled. As it turned out this was at the expense of the thick sheet we had also ordered, however having seen the size of the components to surface solder this was probably a blessing in disguise! A quick search on eBay and the thick sheet was on its way.

We had a few false starts with the electronics. On testing the stepper motor driver boards did not all appear to be working – one of them in particular would not turn the motors. This was actually due to the potentiometer being set too low, so simple but took us long enough to figure out.

The biggest issue we had was with the extruder. When we had bought the plastic parts for our Mendel the extruder design, now deprecated, required a splined motor shaft. In the absence of tools to do this ourselves, we ordered a gear wheel to grip the filament. But try as we might, it would not grip enough to print. By this time there were several alternative geared extruder designs around that were being used with success. We plucked for Wade’s extruder, and quickly established that hobbing a bolt yourself is quite tricky! We managed one that worked OK, but have since replaced it with one from GRRF, where we also got our insulated nichrome wire.

2011: The Year Of Printing

Our Mendel is extruding plastic, so onto the (hopefully) last challenge before successful printing – software calibration. More on our experiences with this to follow!

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