Wednesday, 7 September 2011

Finishing the Main Build – the X-Carriage and Print Bed

Installing the X-Carriage went pretty much without a hitch. Pretty well all of the steps described in the Visual Guide http://garyhodgson.com/reprap/prusa-mendel-visual-instructions/ (i.e. installing the pulley on the motor, installing the motor, installing the PLA bushings and the X-Carriage, and installing the belt) were repeats of steps encountered earlier in the build process, so no new problems to resolve here. Again, the PLA bushings were initially very tight, but freed up quite quickly with a bit of oil, and sliding them along the X-Axis a few times.

I then installed my Wade’s Extruder http://julianh72.blogspot.com/2011/08/wading-in-wades-geared-extruder.html complete with Hot End http://julianh72.blogspot.com/2011/08/my-parts-list-hot-end.html  onto the X-Carriage – as much to give it all a safe place to live as anything.

I’m still waiting (and waiting … and waiting …) for my RAMPS kit to arrive, so I fitted the upper print bed plate at this time as well – again, to get as much done as possible now, and to keep all of the parts together. Again, no real dramas here, apart from the issue of limited Y-Axis travel that I discovered earlier in the build http://julianh72.blogspot.com/2011/08/assembling-y-is-there-always-something.html . The method of mounting the top plate on the bottom plate with 4 screws and 4 springs works well – it allows easy alignment of the top plate for horizontality in both X and Y directions, while holding the plate firmly in position when you have the alignment just right.

So – there we have it! The structural / mechanical build is now complete, but until I get my electronics assembled, it’s all show and no go!

I’m actually very pleased with how it’s all gone so far. The machine looks and feels really solid, and while it looks like it has been designed by an engineer who knows what they are doing, it also has the distinct “look and feel” of a back-yard shed home-brew project. (Somehow, you can tell this wasn’t bought in a high-street electrical appliance shop!) I’m really pleased that I went for the “source from multiple vendors” option – it kept my costs down, and I had to resolve a few design and fabrication issues along the way – all part of the learning process. More importantly, I know intimately how my machine is built and how it all goes together, which I suspect will prove to be vital when it comes time to commission, fine-tune, and maintain the printer in operation.

All of the motions seem smooth enough to me, and the forces involved in moving the components around don’t seem excessive, but I have no experience with a 3D printer or with these motors, so I just don’t know yet if it is even capable of moving, let alone how precise and repeatable the motions will prove to be.

I have developed quite an affection for my machine (is this sounding a bit too weird?) – I’ll have to give it (her?) a name. (Well, if Sebastian Vettel can give his Red Bull Formula 1 cars names like “Kinky Kylie” …. ) Suggestions, anyone?