Hello and newbie question.

Hey all, first post!

Have been lurking for a week or so and have to say i love the whole idea behind this project, it's like magic, both the creating things out of thin air aspect and the opensource side of things too, spot on!

So i looked around and saw all the kit's for sale, but i love a challenging project so i'm gonna attempt to build one, not an expert in any field, but i can be kinda handy.

Ultimately i would like to end up with a mendel, so will need to do a repstrap first and reuse some parts to make a mendel.... can i use Mcwire motors in a mendel by altering the mounts or vicea versa, or will i need two sets of motors? or is there a better way i have not come across yet?

Looking forward to passing on my first set of printed parts.

Mendel uses Nema 17 motors (and has mounts that will accept Nema 14 as well), and I believe that the McWire uses Nema 23; you should verify that though, as I haven't built a Mcwire, only Darwins and half a Mendel so far.

One thing to keep in mind though - screw driven stages are quite slow compared to belt driven stages. On my Darwin (Nema 23 motors), I run about 16 mm/s, mostly due to extruder limitations, and it takes me about a week of printing time (real time is about 4x more for me) to print a set of Darwin parts. Most of the Mcwire's I've read about top out at around 4 mm/s of head speed, which means you're looking at about a month of printing time, running the Mcwire 24/7, to print out a Darwin. It's possible, but I'm not sure anyone has actually printed out a complete Darwin on a McWire yet.

My printed belt driven Darwin seems to run ok at 45 mm/s, and I'm just working on a faster extruder to keep up with it; I hope to cut the build time down to a couple days. However, in reality, I think Nophead has the record for build time, and it took him at least two weeks, extruding at around 16 mm/s and moving a bit faster when not extruding.

So, if you've got lots of free time, go for it, but don't expect it to be quick!

Wade

Wade Wrote:
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> However, in reality, I
> think Nophead has the record for build time, and
> it took him at least two weeks, extruding at
> around 16 mm/s and moving a bit faster when not
> extruding.

That would mean that printing a Darwin requires 19 kilometers of extruder head travel and presumably close to that much filament right?

Reprobate Wrote:
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> Hey all, first post!
>
>
> Ultimately i would like to end up with a mendel,
> so will need to do a repstrap first and reuse some
> parts to make a mendel.... can i use Mcwire motors
> in a mendel by altering the mounts or vicea versa,
> or will i need two sets of motors? or is there a
> better way i have not come across yet?
>
> Looking forward to passing on my first set of
> printed parts.


why build a RepStrap, unless you're into robotics like me and want that extra challenge, there surely will be someone around that can print parts out for you.

I have seent he Mendel up close and personal, and it looks a lot better compared to MakerBot with a bigger build volume

Thanks all for replies

Although i do have pleanty enough spare time, that does seem painfully slow, perhaps i'll look into repstrapping a mendel.... main thing was i hoped to avoid purchasing the motors twice as it's a fair chunk of the cost... but the mcwire design seemed more achievable (without the help of rapid prototyping)

I don't know anyone who can print parts for me, but i do have an interest in robotics and pretty much anything technical in nature.... to quote something i read on these forums "it's for the journey more so than the destination"

One thing is for sure, it's gonna be a real time sponge

Sorry to go a little off topic

wade said
My printed belt driven Darwin seems to run ok at 45 mm/s, and I'm just working on a faster extruder to keep up with it; I hope to cut the build time down to a couple days. However, in reality, I think Nophead has the record for build time, and it took him at least two weeks, extruding at around 16 mm/s and moving a bit faster when not extruding.

I am still culibrating my dawrin reprap and so very intersted in speed.
My MK4 maker bot extruder and V2 bit's from bytes reprap are running at 40 mm/s
Am I going too fast. I mean it seems to work fine but I don't want to break it.

Stephen

I am building a McWire - with NEMA 17s. BUT I haven't tried them out yet, as I haven't got to the connecting them up point. Nearly there, but then I thought that a couple of months ago. Unfortunately, I have had to put it all away, probably until after Christmas now.
You can see my blog of progress (see below), which may hold a few useful tips on the McWire. Check out others' blogs, too. I found that most helpful.

And yes, it sinks time. But is good fun! (I started back at Easter.... and was hoping to have finished before October, ha! some hope!)

Good luck and have fun with yours, and let us know how you get on.

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Hazel

[copycatbot.blogspot.com]

i dont know if anyone has tried to do a belt drive mcwire yet but ive thought about it a litte and believe it would be posible

I noticed something strange with the speed when I switched from the Gen 2 firmware to the 5D firmware. When I was using the Gen 2 firmware, I could run up to 50 mm/s with no problems. If I pushed it to 55 mm/s, the Y-axis would occasionally skip and I would get messed up builds. After I switched to the 5D firmware, 50 mm/s didn't work at all. I ended up slowing it down all the way to 25 mm/s. Anything above 30 mm/s would cause the y-axis to skip.

A part that took about 40 minutes to print with the gen 2 firmware set to 50 mm/s took about 40 minutes to print with the 5D firmware set to 25 mm/s.

The flowrate/feedrate ratio had to be twice as large on the 5D firmware.

So, at least one firmware is off by a factor of two and we might be comparing apples to oranges here.

We should compare the predicted time by Skeinforge to the actual time to print something to try and figure this one out.

MotorAssist Wrote:
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> I am building a McWire - with NEMA 17s.

Thanks Hazel, this is what i was (badly) trying to convey with my original post... using nema 17's instead of 23's, with the mcwire design.
I believe from my reading thus far, that the electronic side of things will be fine, so long as the stepping is 1.8 degrees, the sticking point may be a lack of torque though....... would this be correct?
Had a look at your blog, i'm sure it will be very helpful to me as it's just what i had in mind. Thanks for the links.

Edited 1 time(s). Last edit at 11/20/2009 07:00PM by Reprobate.

I asked this, too, before I started. The general opinion was that NEMA 17s will be fine for the McWire, but not strong enough (torque too low, or borderline) for the Darwin. The Mendel uses NEMA 14s.

Hazel.

Excellent, thanks. I guess i didn't search hard enough then if it's been discussed before.
According to the mendel documentation, you can use 17's or 14's, which means it could take the 17's from your Mcwire when building your mendel, think this is the path i will take, wish me luck, i'll need it! :p

I have Nema17 fuly working in a 3D cnc BodgeIt version of the Mcwire. It has only run for a few hours at a time. The much heaveyer Repstrap Bertha using Nema 23 steppers has run continuesly for several days without problem.

I have two Darwins mechanicaly built with Nema17 steppers one with roller bearings and drive belt one with nylon bearings and belt. I have not connected a full set of controll hardware to test but from my previouse experience with the Nema 17's. I dont think there will be a much of a problem usng them.

The main problem with Darwin is getting true alignment.
I made a measureing template to cut the threaded bar to size and to position the nuts joining parts on the bars a simpler aplication of the pull your self together Bot idea from Zack.

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Bodge It [reprap.org]
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BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]