A RepRap is Born

This page is a blog of my first RepRap build, made over a period of about seven months. If you don't know what a RepRap is then head over to reprap.org, basically it's a machine capable of printing 3D objects; including many of the parts needed to build itself.

February 2012

Second complete set of RepRap parts

Last weekend I switched back to red plastic and printed another set of parts for a mini-Prusa. This set is considerably better quality so I've decided to build my second RepRap using these instead:

Earlier in the week I assembled the basic frame, the following photo of it sitting next to its parent shows how much smaller it is:

Also on the table in that photo are new pieces for a Mendel x-carriage which I printed last night, I've been experiencing a number of problems with the Mendel including bad back-lash that I'm having difficulties getting rid of. I suspect the culprit is the original x-carriage pieces which are heavy, inflexible and somewhat warped. Hopefully these replacements will go a way towards continuing to improve the quality of my prints.

I also spent some time this week packing mini-Prusa pieces onto 150x150mm plates i.e. the size of its own print area. Turns out you only need 2 plates to print all pieces for both a mini-Prusa and a NEMA 14 extruder:

What I'm left with now is a complete set of teal-coloured RP parts, plus numerous spares in red and green. It's not the best quality set in the world, so I wouldn't feel comfortable about trying to sell them, but functionally they should work fine. If anyone has any suggestions as to what I should do with them then I'm all ears.

First complete set of RepRap parts

They're not the prettiest pieces in the world but my Mendel has achieved a new milestone by printing a complete set of parts for a whole new machine:

The target machine is a much smaller mini-Prusa, but it's a complete set none-the-less. Unfortunately the teal plastic I used turned out to be a poor choice and the quality of the prints suffered greatly as a result; I suspect the coloring agent wasn't mixed with the original PLA properly because the extruder kept spitting out large globs of teal-colored liquid that dried to a crusty, flaky mess. In any case with a bit of clean up they should be good enough to use, and if any aren't then I can always print out replacements for them. The only parts I wasn't able to print were the two pulleys; the quality just wasn't good enough, so I picked out a few earlier prints that I did in green.

Studding is cut, nuts and bolts have all been built, and bearings are on their way from China. I'm ready to begin...

Heat bed woes

This past weekend was another RepRap Users Group meeting, there was a great turn-out this time round and I got to meet a lot of new faces. I had my 4-month old son with me (get him into RepRap early, I say) and no car, so I wasn't able to take my machine along, but it was a good chance to see so many other people's builds.

With regards to my own build, my prints this week began exhibiting warping along the bottom few layers and "wavy" edges, as shown in the following photo:

To cut a long story short it turns out both my heat bed and extruder were running about 20 degrees too hot, and I was also extruding plastic about 40% too fast. The nozzle was basically pushing plastic down into the lower layers and causing them to bulge out. The following shows prints of the same piece before and after calibration:

In other news I've started work on my second RepRap, this time I'm making a "Mini Prusa". Prusa is a simplified version of the Mendle I built, and local RepRapper Auzze has designed a 25% scaled-down version which I saw over the weekend and instantly decided I had to have. Rod, studdings, nuts and bolts were purchased this morning, printing of the RP parts begins tomorrow. My obsession with RepRap has entered a new phase...

New extruder and heat bed

This week was spent outfitting the printer with the new extruder. The Herringbone extruder was quite a finicky device to build in the end. It's considerably more difficult to mount than the other two extruders I built, but the results have been well worth it by way of better quality prints:

(And yes, it works!)

I also finished the heat bed and mounted that to the Y axis:

Now that I have a heat-bed I've had another attempt at printing ABS plastic which is supposed to be stronger than PLA. Unfortunately results haven't been promising so far. In the following photo the first piece is one I printed a few months ago in PLA, the next two are versions I printed this week in PLA (the shiny side was in contact with the heatbed glass) and the last piece was one I also printed this week in ABS:

I haven't calibrated the RepRap for ABS yet but even so it seems to extrude "blobby", has more trouble sticking to the bed and just doesn't produce good results. Of more concern is the fact that it jammed my extruder....again! ABS is normally quite soft but when it's heated and cools down it seems to go very hard. This seems to have happened in the PTFE liner in my heater nozzle, and since the drive bolt couldn't push the filement through it proceeded to tear it to shreds:

For the time being I think I'll stick to PLA and maybe give ABS another go with my next machine. My next task is to finish off calibration and then start work on printing the parts for a whole new RepRap. Exactly what I do with those parts, I haven't yet decided...

Printer upgrades

The past two weeks have been spent making some upgrades for my printer. First up, I've finished the Herringbone extruder (designed by rys-jones). I haven't had a chance to test it yet, that'll happen over the next couple of days, but so far it's looking good. It incorporates a number of things from other extruders including prime-numbered herringbone gears, support for an Adrian's hot-end (and also the J-Head which I'm using) and the Wades hobbed drive bolt.

I also made an "Open X" carriage (designed by Buback) which unfortunately turned out to be incompatible with the Herringbone extruder. It's a great design though so I'm planning to modify it and see if I can get the two to fit together:

Finally, I've done some initial tests of my heat-bed, which was designed thanks to some tips from Auzze. Using only a top sheet of aluminium I'm able to maintain 75 degrees C, certainly hot enough to print PLA and hot enough to print ABS according to some. I'm planning to attach a single-sided PCB to the bottom, the fiberglass should provide insulation and help bump the temperature up to over 100 degrees which I can then program my Repic electronics to control with a thermistor:

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