So I am planning on building one of these wonder machines in near future and I just wanted to hear if anybody
has got one.
I also post this because I think this machine is incredible for robot making, and I havent seen anyone mention it, so I just want to put it out there :)
It seems that there aren’t many RepRaps being made for sale (not enough cheap RepRap parts, anyway) – but that might change in the future. I was wondering if it’d be possible to make a RepRap extruder using a hot glue gun nozzle, or an actual built-to-spec RepRap extruder nozzle, a length of nichrome wire, and a thermocouple. Anyway, best of luck! There are some 3-axis CNC machines around on this site that could be used with a RepRap extruder to bootstrap some Mendel parts…
I’m building one too! I’m going to build the repstrap “seedling” and then possibly upgrade to mendel. Currently I’m working more on the hardware - just got my stepper motors today (for 95 cents each!). The extruder seems like it’ll be the hardest part; the electronics seem easy but expensive. I think some folks here have got circuit board printing machines, maybe we could get them to make the motor drivers?
it also seems like it could be a great community thing - we could print gears and gearboxes, for example, or wheels or even robot chasses.
I’d expect there would be more interest in a kit than just the PCBs – I’d wonder whether there was a preferred configuration, since any set of adequate stepper drivers would be able to drive the 3-axis positioning part of the machine. For example, a HobbyCNC board could work, or any of the RepRap stepper drivers (that’s what I’m using), or a set of SparkFun EasyDrivers (current control up to 750mA). The cost of $15/pc for the EasyDrivers matches about what a RepRap Driver kit would cost and it’d be assembled already.
Is RepRap pedigree important to folks? I mean, if the drivers work but it isn’t a RepRap driver, is it still okay?
If folks aren’t 100% happy with something, they probably won’t buy it.
-John
ps - estimated prices, not including shipping:
$50-$60 USD for 4-axis stepper drivers (3-axis machine, plus a driver for the extruder)
$36-$60 USD for 4x NEMA-17 15ohm/coil or 35ohm/coil steppers
$0-$10 USD 4x Motor couplings (polymorph) – DIY or specify size of lead screw – node/15354
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$90-$140 USD Motors and Drivers (doesn’t include Arduino/Sanguino or extruder temperature-control electronics)
I’ve recently gotten a Makerbot – because it’s just not easy to find Mendel parts in the wild (the printed parts that is). Estimates I’ve seen all tend towards 90 hours to print a full set of Mendel parts (not counting failed prints) – that’s a lot of printer time, and a lot of operator time. I find with my Makerbot I am babysitting about 1/4-1/3 of it’s runtime, and after 5-6 weeks of printing I’m just getting to the point where about 75% of my prints are successful. Someday I do hope to print a Mendel on my Makerbot, mainly for the increased build area – but it’ll pretty much take a month or more of time to print all those parts and assemble/tune the new Mendel.
A 3D printer is an amazing tool, but do realize this is all still very bleeding edge, it’s not plug and play, it’ll take a number of hours to assemble, and much more time to tune, and learn the tools required. Even then, expect to want to hack and extend it to do things it currently doesn’t that you desire.
I think the whole point of reprap is that you can make it out of generic parts. I don’t think pedigree is important, just that people want to make sure other people are using the same things as them so they can get help if they need it. And i think the extruder motor does not need to be a stepper (I think servos or even plain dc work fine? but I think DC motors can be sloppy).
I don’t know if you would want to include the stepper motors in that kit though - it’s easy to scrap them or buy them secondhand (I got them 95 cents a piece).
I’m also planning out a picaxe-14m-based motor controller that seems to be feasible (and cheap), but I will have to see if there are enough outputs for the optical endstop (but there should be). Or I might just buy the reprap controllers (if they’re ever in stock) to simplify things.
I guess what I’m saying is that there are a lot of non-obvious ways to save.
And it was hard and so worth it. Its up now the in the “Something Else” section, look for “Nord”. I think that the build time for other parts is greatly reduced on a Mendel than a Makerbot, but the Makerbot kit is way easier to get a hold of at this point.
So far I found a good deal on the nut and bolts and rod locally, but had to order online for electronics and bearings. If I built another one, I would concentrate on sourcing the electronics in a more DIY fashion, as I bought Makerbot electronics.
Concerning the printable pieces, the Reprap forum has some links to people that have made them out of wood, and carving/milling seems to be the quickest way to get going.
I’m drawing a grid tonight on my Mendel in order to tune its scaling. Soon I might be able to provide some parts for other Let’s Make Robots members. Maybe if we team up then we can proliferate these cool machines even quicker!
I’ll need to resource some ABS plastic, but I was planning on paying the bot minimum wage (locally ~$7) per hour for his services. Other than that, just tell me what type of extruder that you would like, and I’ll skein it and quote you. If this offer sounds reasonable to you, we can do it!
