Another 3 Axis Position System for a RepStrap

no, the text is not necessary... it is just identification text for each piece.

right now it says stuff like this:

"X Stage"
McWire Cartesian Bot v1.0
www.RepRap.org

it could be shortened to:

X Stage - MCB v.10
www.reprap.org

or simply assign each part a number/letter, and then have the main reprap text only one one part. once we get to the point of getting them manufactured, then we can get different cost estimates and such, and decide what the best route is. i'd like to strike the best balance between cost and ease of assembly.

i got some pieces with size 7 writing, size 4 writing, and size 2 writing... if the small writing is easy to read, perhaps i'll just make all the writing that small.

also, once we get a design ready for prime time, we can get cost estimates from a bunch of different places, and go with the cheapest one. i'm posting the files i sent to pololu in case anyone wants to get an estimate.

Nice work Zach!
It's great to see how you made this new technology blend into RepRap so fast!
Hats off!

Looks good, and those component costs look about right.

Is the text silk screened on or do they laser that too? Either way, I'm looking forward to seeing the pics when it comes in.

What's the plan for mounting all the right-angle components? (motors, interrupter blade, z-axis rollers)

>
> Is the text silk screened on or do they laser that
> too? Either way, I'm looking forward to seeing
> the pics when it comes in.

laser etched. depending on the price... i may just make stickers and put stickers on each part. i really really like the idea of laser etching the text though. we'll see how it turns out.

> What's the plan for mounting all the right-angle
> components? (motors, interrupter blade, z-axis
> rollers)

(most of this stuff is exactly off the guys site)

motors: we'll use 90deg angle iron or aluminum. drill holes in that, mount it to the motor, then position motor and mount that to the frame. i'll be creating printable templates for it as well.

interrupter blade: example: the y switch is on the x stage, and above it, on the y stage, there is a slot. my plan was to use some sort of thin, sturdy material (aluminum foil, etc). cut a flag out of that, put it through the gap, bend the edge over onto the y platform, and tape it into place. thats also how all the other ones are done as well.

z axis rollers: the rollers to keep the stage up to the z axis are screwed into the vertical base.

there will be a small amount of minor modifications and drilling that need to be done to the parts, but nothing major. a couple holes will need to be drilled for the z axis rollers, depending on how the heights work out, 5-10 of the lasercut holes may need to be countersunk (super easy). the motor mounts will need to be cut and drilled from either angle iron or aluminum. also, the steel base will need to have some holes drilled in it. finally, the aluminum rails will need to be cut to length, and drilled.

all of these things are something you can do with a hacksaw and a drill (or ideally, a drill press). also, i will be creating printable templates, which will eliminate the need for precision measuring. as long as the templates are applied correctly, then you simply cut where it shows, and you drill where it says drill. yay!

Any idea on the over all lengths of the XYZ axis travel? I looked at the McWire site for this info but didn't see it. Also, just a thought but I would replace the metal pipe caps with rubber pipe caps just for looks and probably much cheaper too.

ZachHoeken Wrote:
-------------------------------------------------------
> laser etched. depending on the price... i may
> just make stickers and put stickers on each part.
> i really really like the idea of laser etching the
> text though. we'll see how it turns out.

cool, no reason not to make it look nice. If someone wants it cheap and ugly, they can use the templates and make it themselves.

> motors: we'll use 90deg angle iron or aluminum.
> drill holes in that, mount it to the motor, then
> position motor and mount that to the frame. i'll
> be creating printable templates for it as well.

Should work well. I used two angle brackets for each. They needed a little drilling/chopping too, but it works.

So... a few more things I've discovered: The way I built it, it's not something you want to take apart & put together too many times. I used nuts & bolts, with the nut on the bottom, so whenever you need to screw something down, you need to get a wrench or pair of pliers down below to keep the nut from spinning. It's just an annoyance, but you can probably avoid it pretty easily. The one that bothered me the most was the Y-motor mount. I ended up installing T-nuts in the bottom of the X stage, so you can just screw the motor down from the top. With acrylic, you might be able to thread the holes themselves. I rebuilt the roller arms so they're threaded, which works pretty well. I still haven't settled on anything for the drive nut mounts. It would be nice to be able to remove them from the top so you don't have to drive it off the end of the threaded rod before removing the stage.

Richard wrote:
> Any idea on the over all lengths of the XYZ axis travel? I looked at the
> McWire site for this info but didn't see it. Also, just a thought but I
> would replace the metal pipe caps with rubber pipe caps just for looks
> and probably much cheaper too.

I haven't measured mine, but I followed his plan fairly carefully and wound up with at least 6" x 4" x 4". It looks like Zach's design is going to be bigger.

One thing to consider is the pipe caps do serve to level it out. The elbows and T on the back of the frame stick down maybe 1/4" below the rest of the pipe. Matching caps on the front will level it out. If you use something thinner, you may need to add some sort of feet under the front to compensate (a bolt with a few washers would do). I've been thinking of putting three adjustable feet on mine anyway.

That reminds me, one thing McWire did but didn't mention was he cut off most of one side of the U channel on the bottom of the X stage so it would clear the cap. I was too lazy to do this, so I just mounted the bottom rails a full 3/4" in from the pipe cap. From the plans, that looks like what you're going to do too. If you're making up parts kits, you could replace the two rails on the bottom with L-channel and reclaim that 3/4" (and maybe save a buck or two).

Hi,

I was also inspired by this design... however, I wanted to use it essentialy to cut porex (foam) a3 sized sheets, so that keeping with the original desing would require a 4xA3 XY plane, which is way too large for my place, so I am working on an alternative design in which it is the head the one that moves (simmilar to tommelise, maybe!). I will keep you posted.

Then, at this point, I have a problem... I thouhgt of using Reprap stepper controllers and comms to drive it, but I haven't found details on how to drive the motors using these controllers, other than using the Reprap suite... are there any lower level details or libraries on this already somewhere, or do I have to go through the source code of Reprap to find out (not that I mind, it is only that I am not that proficient in Java!)

Thanks

Hello, all!

Just a note to mention that I found my way to RepRap via the McGuire Instructable and I've been closely watching developments around here since.

I am completely *ecstatic* about the prospect of a dual RepRap/Mill that could be built in the garage for around $500.00! I teach art and design at university, and building a machine like this (+ producing work after) would make for an absolutely stellar 16-week workshop--just so all the complexity can be tamed enough so as to not frighten smart, energetic but not especially technical people.

Also, I make small sculptures via SLA and ZCorp's 3D printing as part of my own art practice, and being able to work on hardware I could build myself is philosophically highly compelling.

Anyhow, I just wanted to offer a little encouragement and to let you know I have already set aside some money for when a kit-of-parts becomes available.

Cheers,
Chad

Just thought I'd share a photo of my progress with the McWire design:



Nothing's wired up yet, and the extruder isn't done

Looks really good :-) Is that based off Zach's drawings, or just off the original instructable? Also, what are you using for motors?

-Thomee-

That's based off the original instructions. I've been trading tips with Zach, but I didn't realize he posted drawings. I should have been following this thread more closely!

I used the same motors that Zach's using, from Automation Direct.

Is there any progress on this design? Im looking really forward for any news.

Zach: how your design are progress?

I wanna buy one from this kit...

hey khiraly,

i ordered the first-run lasercut parts a couple weeks ago, and they are here now. i started work on it this weekend, but i forgot to order some parts. i did do the first stage assembly. once my parts get here (tomorrow hopefully) then i'll do the rest of the assembly.

i have noticed some design flaws, which i plan on fixing for a v1.1 release. you'll probably want to order a set of those. nothing major.

* the x/y stages were oriented strangely,
* the y stage was too big,
* depending on how tight things are, i may switch to 1" x 1" channel

also, i'm thinking about switching to a spring tensioned skate bearing design, but i'll probably hold off on that until v1.2 or v1.3. i'd like to test it in the real world before i integrate it into the next version. my idea is to have two skate bearings on arms on the inside (instead of one like currently) they would point toward the outside of the stage, and then a spring would pull them together, keeping the stage tight against the aluminum channel. along with that, i'm thinking about replacing the exterior channel that acts as a bearing with two roller bearings. i'll experiment with this and let you guys know how it goes.

look for the new version of the stuff later this week.

Thanks for the updates, Zach! I am really excited to hear about your progress.

Cheers!

> i ordered the first-run lasercut parts a couple weeks ago, and they are here now. i started work on it this weekend, but i forgot to order some parts. i did do the first stage assembly. once my parts get here (tomorrow hopefully) then i'll do the rest of the assembly.

OMG! Please take photos (lot of photos) and post on the main blog or here. A photo is more than thousand of word...

>skate bearings
is it the standard 608 bearings?

>spring tensioned skate bearing design
Cant imagine it (maybe my english skill), would you brother to explain it with some image/photos?

To summerize up:
Is it possible to order from Hungary? (pololu isnt it?)
Does the small text (also cheaper) works? (human readable)
Does the design are based on pipes also? (or do you modified it?)
I want to use the machine for pcb milling and paper milling (puzzle) and architecture modelling (it is like paper milling)

What I would like:
- the pipe design kits (all parts, ready to assembly)
- pcb kit
- stepper motors

Is it possible Zach, that I pay the whole thing to you, and you send me in one packet to Hungary? Or do I put a lot of work (ordering, packaging) to you?
Im not familiar with all of this sites (and dont know how is it working to Hungary)...

khiraly Wrote:
-------------------------------------------------------
> > i ordered the first-run lasercut parts a couple
> weeks ago, and they are here now. i started work
> on it this weekend, but i forgot to order some
> parts. i did do the first stage assembly. once my
> parts get here (tomorrow hopefully) then i'll do
> the rest of the assembly.
>
> OMG! Please take photos (lot of photos) and post
> on the main blog or here. A photo is more than
> thousand of word...

oops, i must have forgotten the link: [flickr.com]

>
> >skate bearings
> is it the standard 608 bearings?

exactly.

> >spring tensioned skate bearing design
> Cant imagine it (maybe my english skill), would
> you brother to explain it with some
> image/photos?

I'll try. It helps if you understand the current bearing arm setup. Right now there is one bearing on an arm that keeps the stage pressed up against the rail. you can see the pictures of that on the original McWire design.

I'm proposing to add a second arm that is angled the opposite direction, and to add a spring that pulls them together. Also, it would replace the second aluminum rail that is attached to the stage and moves with two 608 bearings.

I've made a crude drawing and attached it to this post.

> To summerize up:
> Is it possible to order from Hungary? (pololu isnt
> it?)
> Does the small text (also cheaper) works? (human
> readable)
> Does the design are based on pipes also? (or do
> you modified it?)
> I want to use the machine for pcb milling and
> paper milling (puzzle) and architecture modelling
> (it is like paper milling)


Well, I dont know if Pololu will ship to Hungary, but when I do my next order, I can order an extra one for you, and then ship it to you. I think I'd like to do one more round of lasercut parts before I offer this as a general kit for people.

The small text is actually very readable, and I'll change all the text to this smaller text. It should make the kits a bit cheaper.

The design is still based on pipes. The stages and such are lasercut acrylic, and the rails are aluminum. I'm thinking that this is going to be really awesome.

> What I would like:
> - the pipe design kits (all parts, ready to
> assembly)

i'm contemplating whether to drill the steel myself, or to offer the pipes + sticker templates as a kit. i need to find out how hard this is to do. i also might just make the pipes into its own separate kit.

> - pcb kit

yup, we already sell this, although we dont supply any of the parts. i'm looking into how to do that. i just dont have enough time to make all the part kits myself while leaving time to do fun research as well.

> - stepper motors

yup, i'm planning on stocking them on the store soon. i'll post when i have more info.

> Is it possible Zach, that I pay the whole thing to
> you, and you send me in one packet to Hungary? Or
> do I put a lot of work (ordering, packaging) to
> you?
> Im not familiar with all of this sites (and dont
> know how is it working to Hungary)...

yeah, as long as its something i sell via the RRRF store, anything you order will get shipped out in the same package. i can definitely ship to Hungary, so thats not a problem.

keep checking the thread. hopefully i'll have some cool progress to report in the next few weeks.

oops! i forgot to attach the file, here it is.

I'd be happy to be a guinea pig for the second round of laser cut parts. Are you taking volunteers?

-Thomee-

ZachHoeken Wrote:
> > - stepper motors
>
> yup, i'm planning on stocking them on the store
> soon. i'll post when i have more info.

Make sure they turn fast enough before you buy a bunch of them. I remember EricM had some problems getting his steppers going fast enough to keep up with the extruder's slowest speed. With 20 threads/inch, you need to do 787 steps/sec to move 5mm/sec, many motors become very weak at that speed (using our current drive electronics). I don't know what the magic minimum x/y speed is, but I'm sure someone around here does.

Thomee Wrote:
-------------------------------------------------------
> I'd be happy to be a guinea pig for the second
> round of laser cut parts. Are you taking
> volunteers?
>
> -Thomee-

sure, i'll make a new thread when i'm ready to move to round 2 of the design. if we order more than 1 set of parts, it gets cheaper as well.

i've got a bunch of improvements / fixes in the pipe for it. some really nifty things too.

for example: since we're using aluminum channel, and the inside width is 1/2" we can use 5/16" bolts (with 1/2" wide nuts) to fasten it to the plexiglass. the nut goes inside the channel, where it is trapped, then you simply screw the bolt in from the other side. i'm going to re-drill a couple holes on my current version and use this new method just to check it out in real life before i make the change in the design. also, i'll be specifying flat head machine screws that once you drill out the mounting head, will be flush against the acrylic, leaving you with a very nice setup, and it also helps with some of the crowding issues we have inside the guts. also, M8 nuts/bolts are almost an exact match for 5/16" !!!

emf Wrote:
-------------------------------------------------------
> ZachHoeken Wrote:
> > > - stepper motors
> >
> > yup, i'm planning on stocking them on the store
> > soon. i'll post when i have more info.
>
> Make sure they turn fast enough before you buy a
> bunch of them. I remember EricM had some problems
> getting his steppers going fast enough to keep up
> with the extruder's slowest speed. With 20
> threads/inch, you need to do 787 steps/sec to move
> 5mm/sec, many motors become very weak at that
> speed (using our current drive electronics). I
> don't know what the magic minimum x/y speed is,
> but I'm sure someone around here does.

definitely. i'm not planning on stocking motors until i've personally tested them and gotten them to work. i got a couple that work okay with the current reprap electronics, but they stutter. although i think this is a problem with the stepper drivers and not the motors themselves. (see: arduino as an alternative comms board thread)

Oh, also... last night I made it into the lab, and did the 2nd stage assembly. it went very well!

I used print-out templates with drill marks for the aluminum channels, and it worked great. you have to be careful in a few areas (cutting the sticker, placing the sticker, and drilling on the mark) but it eliminates the need for measuring which is always awesome. i'm not exactly the best craftsman, but all my holes came out very precisely, and everything was very easy to assemble. i definitely consider the templates a success.

what is left to do:

* sand/polish aluminum rails
* hook up the bearing arms
* hook up drive thread
* attach motors
* figure out how to best handle the z axis stuff. i have a few ideas on that.

Okay, you've really got me salivating with these build reports! More pictures when you get a chance, please!

Stuttering steppers? Since the Nanotec models are dual shaft, try attaching a flywheel. It helps the telescope makers keep their systems moving smoothly. Doesn't seem to affect accuracy too much but it DOES affect top end useful speed.

(Addendum)

Whoops, forgot to mention it increases top end useful speed.

Edited 1 time(s). Last edit at 09/26/2007 02:19PM by SOI Sentinel.

apophene Wrote:
-------------------------------------------------------
> Okay, you've really got me salivating with these
> build reports! More pictures when you get a
> chance, please!

okay, more pics in the flickr gallery above.

SOI Sentinel Wrote:
-------------------------------------------------------
> Stuttering steppers? Since the Nanotec models are
> dual shaft, try attaching a flywheel. It helps
> the telescope makers keep their systems moving
> smoothly. Doesn't seem to affect accuracy too
> much but it DOES affect top end useful speed.
>
> (Addendum)
>
> Whoops, forgot to mention it increases top end
> useful speed.

well, i'm not using the Nanotec steppers. they're too expensive for me. I'm using some Surestep motors, and i dont think they're particularly matched for the reprap electronics. with the v1.2.x stepper controller boards, the L298 are driven directly from the PIC, so my guess is that the software is not driving them optimally. once i get a better motor driver, that problem should solve itself.

Some questions...

Will this design work with the existing RepRap software? I.e. is it just a matter of changing a few configuration options somewhere?

Are the files/design released under the GPL?

Will you be adding support for two extruders side by side? Or is that not how the support extruder is supposed to be used?

Andy

Andy Wrote:
-------------------------------------------------------
> Some questions...
>
> Will this design work with the existing RepRap
> software? I.e. is it just a matter of changing a
> few configuration options somewhere?

yes, it will be compatible with reprap electronics / software. from an electronics/software standpoint its still a 3 axis cartesian robot, with an extruder (and eventually support extruder). you will have to set parameters in the host software to specify the working area, how large a step moves your axis, etc, but that is relatively easy.

> Are the files/design released under the GPL?

absolutely! they're currently stored in RepRap's subversion repository in my playground folder.

> Will you be adding support for two extruders side
> by side? Or is that not how the support extruder
> is supposed to be used?

yeah, eventually. you could either: mount both extruders side by side on the mounting plate, or make individual plates for toolheads that can be easily swapped.

to start, i'm going to make it a drawing bot, and then move up to extruding. gotta start with the basics. =)

>> >spring tensioned skate bearing design
>> Cant imagine it (maybe my english skill), would
>> you brother to explain it with some
>> image/photos?winking smiley

>I'll try. It helps if you understand the current bearing arm setup. Right now there is one
>bearing on an arm that keeps the stage pressed up against the rail. you can see the pictures of
>that on the original McWire design.

>I'm proposing to add a second arm that is angled the opposite direction, and to add a spring
> that pulls them together. Also, it would replace the second aluminum rail that is attached to
> the stage and moves with two 608 bearings.

>I've made a crude drawing and attached it to this post.

Ok, I understand now. Im favor of this modification I find it more durable as the old one.
In the old design, the second aluminum rail will wear more quickly.

> Well, I dont know if Pololu will ship to Hungary, but when I do my next order, I can order an
> extra one for you, and then ship it to you. I think I'd like to do one more round of lasercut
> parts before I offer this as a general kit for people.

I would really appreciate it!

(I have read the international shipping information on pololu website. Basically I need to contact them and tell my address and what I would like to bux, and they will write me back with the chipping charges. An important factor is the duties is my responsabilities (need to be clear with my local law), so the duties depends normally the value of the packet.
To summerize up, it sound rather complicated.)

>The small text is actually very readable, and I'll change all the text to this smaller text. It
> should make the kits a bit cheaper.

By the way. I have a small idea about the texts. We could assign a letter-number combination to each part, and it would be a direct link to the web. Im thinking something like that:
McWire design, Y stage -> mc-3 and the link would be: objects.reprap.org/mc-3
Similar in the darwing design:
Corner bracket -> d-23 -> [objects.reprap.org]

It would help the identification.

> The design is still based on pipes. The stages and such are lasercut acrylic, and the rails are
> aluminum. I'm thinking that this is going to be really awesome.

Yes, definitely it will be awesome !

> i'm contemplating whether to drill the steel myself, or to offer the pipes + sticker templates
> as a kit. i need to find out how hard this is to do. i also might just make the pipes into its
> own separate kit.

Sometimes metal drilling can be hard, and require a variable speed drilling machine. (the cheapest models are usually two speeds). So Im in favor of predrilled pipes...

>> - stepper motors

>yup, i'm planning on stocking them on the store soon. i'll post when i have more info.

thanks.

>yeah, as long as its something i sell via the RRRF store, anything you order will get shipped
> out in the same package. i can definitely ship to Hungary, so thats not a problem.

Super. Are you located in the US?

>keep checking the thread. hopefully i'll have some cool progress to report in the next few weeks.

Im constantly checking it.


Thank you for your positive reply.

>
> > Well, I dont know if Pololu will ship to
> Hungary, but when I do my next order, I can order
> an
> > extra one for you, and then ship it to you. I
> think I'd like to do one more round of lasercut
> > parts before I offer this as a general kit for
> people.
>
> I would really appreciate it!
>
> (I have read the international shipping
> information on pololu website. Basically I need to
> contact them and tell my address and what I would
> like to bux, and they will write me back with the
> chipping charges. An important factor is the
> duties is my responsabilities (need to be clear
> with my local law), so the duties depends normally
> the value of the packet.
> To summerize up, it sound rather complicated.)

yup, i'll ship it out to you with a super-low research valuation. researchers shouldn't have to pay duties!!!

> >The small text is actually very readable, and
> I'll change all the text to this smaller text. It
> > should make the kits a bit cheaper.
>
> By the way. I have a small idea about the texts.
> We could assign a letter-number combination to
> each part, and it would be a direct link to the
> web. Im thinking something like that:
> McWire design, Y stage -> mc-3 and the link would
> be: objects.reprap.org/mc-3
> Similar in the darwing design:
> Corner bracket -> d-23 ->
> [objects.reprap.org]

Yeah, I definitely want the parts to be identifiable, and make it easy to look up on the web. I'd like to keep the english version of the name on the part, with a url for more info, as well as the version of the main module being built. Example:

"X Stage"
McWire Cartesian Bot v1.0
[foo.reprap.org]

or something like that. as long as the text stays small, it really doesnt add much to the cost, and the extra readability is definitely worth it.

> > i'm contemplating whether to drill the steel
> myself, or to offer the pipes + sticker templates
> > as a kit. i need to find out how hard this is to
> do. i also might just make the pipes into its
> > own separate kit.
>
> Sometimes metal drilling can be hard, and require
> a variable speed drilling machine. (the cheapest
> models are usually two speeds). So Im in favor of
> predrilled pipes...

i drilled the pipes last week on my cheapo $80 drill press and it went fine. i used a sharp bit, multi-purpose oil, and a slow speed (not sure what speed to use) it went really well. i will definitely consider offering a pipe kit for those who dont wish to take on the challenge. keep in mind that shipping metal pipes overseas is going to be rather expensive....

> >yeah, as long as its something i sell via the
> RRRF store, anything you order will get shipped
> > out in the same package. i can definitely ship
> to Hungary, so thats not a problem.
>
> Super. Are you located in the US?

yup, New York City, USA!

> Thank you for your positive reply.

you're welcome! your interest in this is a good motivation.