Official way to qualify as a "RepStrap"

Good morning!

As mentioned in another thread (see [forums.reprap.org]) I am close to finish my work on a "RepStrap" built from FischerTechnik parts (and only a few other elements) - next week, I plan to set up the tool chain which will eventually allow to print "arbitrary" models.

My question is now: what is the official way to "qualify" as a "RepStrap"?

My FTIStrap already meets most of the project goals:

* "The RepStrap should be buildable by somebody with no special knowledge or expertise"

This requirement is definitely fulfilled: you build it from FischerTechnik parts, no soldering is required (just use FischerTechnik interfaces), you only have to disassemble a hot-melt gun and build a housing for it from balsa wood

* "The RepStrap should only require a minimum of tools and those that are needed must be readily available around the world and be low cost"

At least, a sharp knife is required, a small saw would be better, though - but no other tools.

For several reasons, the "FTIStrap" might be more interesting for people living in Germany - thus, I would like to reduce the requirement "around the world" to "in Germany". But there, building it from FischerTechnik parts (which may later be disassembled again, and used for other models) might be a real alternative...

* "All construction materials must be common materials that can be sourced locally in the majority of the world at low cost"

FischerTechnik parts may be ordered online, the hot-melt gun and the glue sticks as well, balsa wood is available in model stores and the glass plate in many supermarkets.

* "The RepStrap must be able to produce a 100% complete RepRap"

How will I have to proove that? Will I have to print all parts and send it to Mr. Bowyer? Or will I have to bild a RepRap and send a foto in?

Additionally, I will also have to prepare instructions how to build the "FTIStrap" - I am working on that now.

Thanks in advance for any information.

Edited 1 time(s). Last edit at 10/02/2008 03:01AM by Andreas Rozek.

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Kind regards,

Andreas Rozek

I don't think there is anything as formal in the RepRap project as official qualification. I am sure if you make the parts for a RepRap with it and post pictures we will all believe you.

HydraRaptor has made all the parts for a Darwin, so I would definitely claim it to be a RepStrap, but it doesn't meet many of the goals you mention. The main thing is that it bootstraps you into the project. Once enough people are able to make parts for others so that Darwin parts are readily and cheaply available, RepStraps become largely irrelevant.

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[www.hydraraptor.blogspot.com]

I think that the main criteria for a Repstrap is that it bootstraps you into being able to build a self-replicating machine, not that it enables you to necessarily build a Darwin and join the main development stream of the project.

if you look right at the bottom of the reprap.org home page you will find a Glossary section, which says:-

RepRap - n. any free rapid prototyping machine that can manufacture a significant fraction of its own parts; v.t. (in lower case: to reprap) to make something in a RepRap machine.

RepStrap - n. any free rapid prototyping machine that doesn't make its own parts, but is intended to make parts for a RepRap.

reprapper - n. a person engaged in making or using RepRaps or RepStraps.

reprapable - adj. capable of being made in a RepRap machine.

... then it's the same again (remember some old discussions) with a homebrewed CNC-mill: - this definition classifies this CNC-mill as RepRap, because i can make most mechanical parts for a new one and the PCB's (what's more, then Darwin is capable to do!) and need only the mill-head, the stepper-motors, some linear bearings and the electronic components ...

Viktor

I doubt that every homebrew cnc-mill can replicate it's structural parts.
I think maybe 10-20% of homebrewed mills are capable of millig the material they're made of.

milling aluminium is not as easy as it may sound
And that "cantrememberwhatsitsname" hdpe-made cnc mill that appears on ebay every once in a while will surely mill hdpe, but it's not able to mill parts large enough to selfreplicate

'sid

davidgoodenough Wrote:
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>
> RepStrap - n. any free rapid prototyping machine
> that doesn't make its own parts, but is intended
> to make parts for a RepRap.
>
Yeah, that was my understanding. The new builders wiki that Adrian just set up, though, modifies that a bit...

"A RepStrap is a homebuilt 3-axis positioning system used as a 'bootstrap' machine to fabricate a Darwin RepRap 3D Printer."

I don't know if that focussing in on Repstraps are supposed to only make a Darwin is going to be the new dogma or not. I'm making inquiries, because if that is the new reality I've no place here.

Well a repstrap is to make the parts for a reprap, later that millenium a mendel, but for now a darwin

And if it can make a darwin, it can make almost everything that is not larger than the largest part of the darwin, not? (and some parts that are)

If it can do more than that like hydraraptor is capable of some serious milling, and it appears your tommelise, too

that's truely a benefit, but not necessary for the goal of a repstrap, is it?
Otherwise darwin wouldn't be a repstrap but a reprap, and that's where we'll run into some troubles with definitions

Andreas, you tried printing any thermoplast yet? or still "just" hotmeltglue?
I doubt that hotmelt is strong enough for building a working darwin (sorry forrest, for most of us darwin is the first goal to attain, beyond that there are no limits though )

'sid

@Forest

Bah! Don't be so melodramatic...you belong here cause you make suggestion and ideas that contribute to the main project even if the machine you are working on gets "defined" out of being a repstrap.

Demented

Oops,

I did not imagine starting a discussion about definitions...

To my current understanding, it will be sufficient to print the "plastic" parts of a Darwin to "qualify" as a "RepStrap" - ok, I will try that next week (if time allows)

Sid: don't underestimate the stability of hot-glue if you use enough material (i.e. make the walls thick enough). One of my first 3D prints accidentially used far too much material - but turned out to be really stable.

I will give it a try, at least - let's see how the result behaves!

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Kind regards,

Andreas Rozek

Forrest Higgs Wrote:
-------------------------------------------------------
>
> "A RepStrap is a homebuilt 3-axis positioning
> system used as a 'bootstrap' machine to fabricate
> a Darwin RepRap 3D Printer."
>
> I don't know if that focussing in on Repstraps are
> supposed to only make a Darwin is going to be the
> new dogma or not. I'm making inquiries, because
> if that is the new reality I've no place here.
>

Whew! That inclusion of Darwin into the definition was an typo by Adrian. He's fixed that.

Demented Chihuahua Wrote:
-------------------------------------------------------
> @Forest
>
> Bah! Don't be so melodramatic...you belong here
> cause you make suggestion and ideas that
> contribute to the main project even if the machine
> you are working on gets "defined" out of being a
> repstrap.
>

If things go right Tommelise 2.0 will be milling or extruding most of the parts, including the stepper motors and PCB's, for Tommelise 3.0.

The FTIStrap Doesn't need to produce ALL the parts for a darwin to be EXTREMELY usful as a repstrap. If the hot-glue is an issue for most of the parts, that's still OK. As long as it can print out the parts for an extruder, and they work well enough when made out of hot glue. Then you mount your new darwin MK II extruder on your FTIStrap frame, and print out the rest of your darwin...

I'm of the opinion that it's unlikely to be unsuccessful. Though some minor redesign of the extruder parts MAY be needed. They're overbuilt, so even that seems unlikely.

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--
I'm building it with Baling Wire

It's really great that someone is building a RepStrap from Fischer Technik. I just got my 8 boxes or so of it from the basement as my some is becoming of FT age. I've built tons of useful gadgets with FT in the past.

I quick search revealed to my great surprise and pleasure that it is possible to custom-order specific parts, and that they are reasonably priced, even though minimum order amounts apply. I was indeed considering building a RepStrap out of it. Or at least a 2d plotter as a start and to hook up to the Arduino electronics.

If we can get a FT repstrap together, and that should be doable, we could buy parts in bulk and repackage them as individual sets. Many FT parts are made out of ABS, which should be reprapable.

Please post as soon as you've got any plans or partially built things.

-Geert

Geert,

I *have* already built a RepStrap from FischerTechnik parts and it is working quite well using hot glue and a conventional hot-melt gun - see thread [forums.reprap.org] for some pictures.

However, work on documentation and software had to be put on hold for a while because of other business activities. Hopefully, I will be able to continue working on it in the next few days.

Just watch this thread or the one I mentioned above.