New builder in

Hi Reprappers!

I'm about to embark on building a repstrap. Since I already got an Arduino (a farewell present from my former colleges), I figure I will start with the software, then get a stepper motor controlled, then delve into the frame. I have plenty of programming experience, but very little mechanical experience, so I'll probably pop up with stupid questions fairly often

Right now I'm leaning towards doing the McWire design, using khiraly's metric conversion at [forums.reprap.org] (while I know how to divide by 2.54 (or 25.37), I doubt Danish hardware stores sell nuts and bolts in inch-sizes). I like the openness of the McWire design, and it seems quite a lot sturdier than the RepRap-like designs like Ponoko.

But first, off to read a lot!

-Lars Clausen

larsrc Wrote:
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>
> I like the openness of the McWire
> design, and it seems quite a lot sturdier than the
> RepRap-like designs like Ponoko.
>
It's also a LOT slower because you are using high resolution stepper motors to drive pretty fine pitched lead screws rather than belts like Darwin uses. Mind, it's a LOT cheaper than Darwin at present.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

The cheapness is also a factor, for sure. And once I have it running, I can look at builder a RepRap proper if the speed annoys me.

I'm not into this for the replication so much as for other things I could make: cake decoration, lens hoods, boxes for other electronics projects, and all manner of other bits and pieces that I come up with randomly. But if replicating seems like a good idea once the first one is up, I'll do it.

-Lars Clausen

The speed will annoy you a lot. If reports I hear are correct, it can only do a few mm/sec. While that's fine for milling steel, it will take you months to FDM print anything useful at that rate.

All the same, good luck! There are a lot of McWires getting built.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Wow, I hadn't really considered the speed factor of belts vs. screw drive. I know that standard CNC mills use ball screws and can move at a really surprising clip- upwards of 50 mm/sec. what kind of speed are the belt driven repraps capable of?

The belts will get the 30+ mm/sec sorts of speeds. I don't think that the Arduino-based stepper driver that we use with Darwin are sophisticated enough to get those kinds of speeds with lead screws. That's just my impression, mind. I know that Viktor is working with Arduino-based Darwin drivers on a McWire just now. You should keep in contact with him to see what his experience is.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Hi Forrest,

Forrest Higgs Wrote:
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>... I know that Viktor is working with Arduino-based
> Darwin drivers on a McWire just now ...

... hmmm ... i didn't know that

I'm repstrapping with a reworked gantry-style CNC-mill with ballscrews and 40mm/sec at halfstep and with noncartesian parallelkinematic mechanics with higer resolutions (drivers with 1/8 or 1/256 microstepping with 10 kHz max. stepping rate)

Maybe you've pointing towards Vik?

Viktor

Sorry, viktor. I misunderstood what you were doing.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison