Since McWire now has own forum and the Wiki (http://www.reprap.org/bin/view/Main/McWireCartesianBot_1_0 ) has stuff dating back to September... I wanted to report my own recent observations and questions. Having seen a working McWire work in progress, I am excited and intend to build both Darwin and McWire RepStrap.

When I was in NYC last week with Zach, he indicated that he still needed to test the version 1.2 printed laser-cut acrylic parts. He had one set, but is very busy working on the new electronics firmware (Arduino). Zach indicated tome that the previous Laser Cut design (he was working on) didn't properly account for the optical end-stops flags and some other optimizations. I know Zach also indicated that some of the metal support parts had changed.

I'm not sure who besides Zach and Bre on testing/proving this new McWire 1.2 design - but as of yet, I don't think a working one [reflecting the 2007-12-12 SVN drawings] has been assembled. Anyone have info to share otherwise?


My personal observation on "versions"
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I wanted to comment an observation I have on how version numbers are being used in the RepRap project. Coming from other Open Source projects, some people (like me) might assume version "1.0" means "ready for assembly".

What I seem to observe on RepRap is that "version 1.0" is just to distinguish from "version 1.1" and the > 1.0 does NOT indicate things are proven or tested. In other words, some other open source software projects would probably call this "version 0.1" instead of "1.0".

I say this strictly to help eliminate possible confusion, don't consider it a suggestion or criticism.


Brief History
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Version 1.0 [really Alpha?] - Zach has this assembled in NYC and posted photos ( [flickr.com] ) in September 2007.

Version 1.1 [really Beta?] - Bre Pettis featured on Make 2007-11-23. ( [blog.makezine.com] )

Version 1.2 [Release candidate?] - Zach put the revised drawing files in subversion on 2007-12-12 and had a set printed - but Zach is very busy right now and they have not yet been tested/assembled.


Asking for
================
I'm sure I'm not the only one who is at least looking to order parts or do the "scavenger hunt" on the new design.

1. Please let us know if parts.reprap.org version 1.2 BOM is tested/assembled. So far, has anyone done this?

2. The 2007-12-12 drawings for laser cut parts are in the subversion server ( [svn.reprap.org] ) but not yet assembled and proven. Can someone speak up if they have actually tested these out (real parts)?


If anyone knows of activity on these two or has updates to share, please post!

Zach has indicated he intends to organize a group purchase of the laser cut acrylic parts in January; please speak up if anyone is ahead of that. I don't have experience to convert the files or organize cutting myself, but I'm willing to help in other ways.

Edited 3 time(s). Last edit at 12/27/2007 11:23AM by RoundSparrow.

Hey,

Well, I'm really not a fan of v0.x numbering systems. The v1.0 design technically does work, it just requires a bit of fudging to work. The v1.1 was better, and then Bre came up with some great ideas that were put into v1.2.

I'll be assembling, testing, documenting, and proving the v1.2 design when i get back in january. once that is done, then we'll be ready to go and i'll get that bulk order of lasercut parts for people.

the changes are rather small from release to release. the main way the system works has not changed, rather its things like endstop flag placement, etc that are being tweaked to create a design that is easily assembled and *just works*.

also, i created these designs so let me answer your questions:

1. not yet, but it is highly likely it will work. these are incremental upgrades from previous working designs. the parts from the bill of materials are not going to change. the only thing that will is the lasercut parts design which is also ready to go.

2. not tested yet, but they will be once i get back to NYC. rest assured that i'll be documenting the crap out of stuff once i get to it =)

Zach, is there some kind of ETA on these laser-cut parts. I haven't lost faith ... just trying to help out here. Does it make sense that we try to organize a group purchase on our own?

hey,

there are 2 things:

1. the RRRF is under capitalized. all the money is in PCBs and stepper motors at the time, so yes a group purchase is a good idea.

2. i havent assembled the newest version yet. i should be able to get to that this weekend, as i have a 3 day weekend.

Anyone out there tested the version 1.2 prints to help out. Never hurts to have a second set.

Watching your original video on first set you had cut back in October, I know the guy doing the cutting used Corel Draw and had to tweak the prints. Anyone have some help on this?

Also looking for some idea on what price seems fair. i know here in Houston we probably need at least 3 sets... so probably thinking like 5 or 8 sets for the first run.

Yo.

The Corel Draw stuff we figured out pretty easily, its not a problem.

As far as price... it depends on how I get them done.

If I do it through Phil, then it will be cheaper, but the only color will be clear, and I wont be able to get the vertical base in 1/2" thick acrylic, instead there will be 2 * 1/4" thick sheets. Also, its just a single dude doing it, so leadtimes could become an issue if we get lots of people wanting them. This is sort of a bummer. I think he quoted me something like $75/set.

If I get it done through Pololu, then it will be a bit more expensive, but we will be able to get exactly the pieces cut we need (1/2" thick vertical base!) We will also be able to get really good looking colors. I think the quote I got last time was like $100/set.

Thats about all I know right now.

Do they have to be laser cut or is just regular machining good enough?

---

Jay

Jay,

That's all I did for mine. I actually used hand tools to cut all of mine and drilled things with a cordless drill. I made the holes over sized so that I would have adjustment room to make up for my crappy fabrication skills. Worked out well. I have a flat, parallel set of stages that look like shit but function well.

Demented

So if that's good enough, isn't it cheaper to get the parts machined instead of laser cut? I'm not making a seedling, but I'm just thinking about how to reduce cost.

---

Jay

I'm not sure which is cheaper. Machined would definitely work. I find lasercutting to be an easier route.

Ok then. This summer I'm planning on making a cnc-router, and I could probably devote some time to making these pieces. No guarantees or promises, but I think that I'd be able to help with the manufacturing of the sets. That would be in 6-months or so though. Anyways, if it would help just tell me and I'll try to bump up my construction date.

---

Jay

I also thought of using those clip-boards that are acrylic. Not very thick but should work and would cut down cost even more.

For that matter, why acrylic? Just use MDF or plywood or whatever you have to hand. That would cut down costs even further. Most people--I think--have scraps of this sort available to them.

Demented

exactly... if you're making the stages by hand, you can use any flat, 1/4" thick material.

So I'm a little bit confused about the proper thickness of the acrylic pieces?

1/2" or 1/4"? Or does it vary by part?

Thanks,
Ben

most of the pieces should be 1/4" thick. there is one piece that should be 1/2" thick which is the 'vertical base' part.

I just bought some 1/2" for a good price on ebay. Since it's only 9" wide and 48 long it's cheaper then a 18" x 18" square piece.

Here's the link:

1/2" acrylic scrap piece

$7.25 for a piece of 9" x 48".