The 'Strap...

Going all the way back to the beginning i'd say I've been interested in the whole idea of 3d printing (and more importantly the reprap) for some time. However, for about the last year i've started being interested in building and owning one. So for about that long i've been hanging out on the IRC channel just watching what goes on.

Being an engineer of course the first thing I thought was "im going to build one of my own design" which is something alot of people must think (when considering the types that the reprap will attract). Having watched it all for about a year and been designing my own for about that long (well, about 4 different models so far) was a good way of actually avoiding buying and building.

Eventually though (bout 4 months now) i finally decided to take the plunge. But decided to build something that wasnt too different to an M90 (a design that is inherently easy to 'Strap). I bought an extruder and hot end and was planning on building the rest from what I either had in the house or I could get at the local hardware store.

So what parts did I have available, here's the list:

1. Rods (smooth and threaded M8's) from the hardware store.
2. An old ATMEL CPU.
3. Some little metal brackets (also from the local hardware store).
4. Stepper motors and pulleys (from various old printers and computer parts).
5. Cotton String (oh yes).
6. Some bearings (from a local hobby store, lm8uu's and 608 bearings)
7. Control line from printers (instead of timing belts).
8. Power Supply (std atx computer PSU).
9. Everything else from wood (including carriages and mounts), cut myself from MDF (12mm, 6mm) and plywood.

Well, it didnt really turn out that way. The ATMEL controller just didnt have everything I needed to control a stepper (plus my knowledge of electronics is rather week) and i had a hardware failure. What I did end up building was by replacing some of the above with this:

1. Printrboard controller (mildly regret getting this rather then RAMPS).
2. Propper NEMA17 Steppers, T5 pulley's and timing belts (from a local store).
3. Propper X Carriage printed parts (Thanks Greg Frost) for a standard Mendel 90.
4. A Standard MK2 Heatbed (which i actually dont use)

So here's how that all came together:

Yes, alot of my printer is held together with cotton string (though it has been treated to be VERY taught and strong) at this point and you'll notice that initially i was printing without the z-plane connected (added the z-plane after the second print). The little metal bits that everything is sitting on are little cheap brackets from a local hardware store. I also (initially) used a Mendel 90 Vertical Z axis (which wasn't a good choice). Please do laugh if you wish, however one of my first high-res prints (at 0.1mm layer heights) was this (it was about my 8th print):

The full image is available on the thingiverse item from the same object, and a link to my dropbox high-res image for the same object. Not bad for an 8th print? Thanks to the guys on the reprap irc channel and just sitting on there, while reading the reprap forums and pages that my printer worked quite well from day 1. But lets go back to my first prints:

So theres a few issues there but the sizing was correct (second one was stopped mid way as I realised i forgot to actually push a new firmware onto the thing), but thankfully they were easily solved (literally minutes), attached my z-plane properly and here was my third print (this was actually at 0.1mm layer height):

The damage on that print comes from the fact i couldn't actually take it off the bed (blue masking tape that point). Now my fourth (at 0.2mm layer height):

Im pretty proud of the fact that my printer worked so well and from the beginning, and that i could solve my own issues pretty easily. But moving on...

The only problem I had that took me a while to solve was a lack of a working bed. I'd either get prints not sticking, or prints I could not remove. Im printing with PLA, I have a heatbed, i tried kapton tape, blue masking tape, and many many other suggestions i'd read here and there... none worked... The thing that solved this for me was switching off the heatbed and printing onto diluted PVA directly on the glass. Havent had any issues (with the bed) since then, and heres a video showing a PVA bed:

My final objective is to get here (my PJRun design - not complete as of this post):

But I have some objectives for my design:

1. Better bearing clip designs (im not liking clips-ins and cable tie mounts which are fairly heavily used on many models - including the M90).
2. Portability - it'll fold down easily
3. Open Design - its on github
4. Remote extruder motor (not on the Moving portion of the X carriage)
5. Better X-Carriage design (slimmer and will use a counterweight ultimately)

But to get there, I have a few steps first. To begin with, Im replacing the 'strap part of my rap with printed parts (that i've designed myself - see the temporary directory in github for those parts). I'll start documenting those in the next bog posts and show how this then comes together. The bits from my design are also viewable here, on my website (thanks thingiverse for their thingiviewer code).

At this point, i have also published a few of my own designs to thingiverse, my printrboard box and my LM8UU Y-Axis bearing mounts. My next blog post will be all about my software world (and how i live on the linux desktop with a 3d printer).