Atfer Hbot, go to CoreXY.

When it come to the extruded parts, its $16 a meter here. That's for 1"x1" (25mm profiles)
Joining plates are $12ea
Corner brackets are $5ea.
Cap head screw and nut are $1ea.
and of course taxes on top of all that.
So as you can see, kinda outa range for almost anyone.

As for Misumi, I went through the website posted, and it seems Cnds are getting nailed well over $100 in shipping/brokerage fees.

I was thinking about the X axis... and I will take your advise and use 8mm for it.
But I will be using 12mm for Y and Z.

As for the MDF... you maybe right, but you maybe wrong
I have an idea that would keep it rigid enough for the job.
And if it fails, well, lesson learned, and will be about $15 in materials.

It's mostly awesome living on an island, but sometimes it really sucks.

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I think it will be possible to adapt the Y axis to 12mm, but it's probably difficult to keep the XY-block inside the frame, which is a requirement for me.
The extrusions I used are 20mm.
The Z-axis will be 12mm, so no problem here.

Hang on FreeCAD sources and STEP files will be available soon!
But now it's time to go to bed.

Please note:

THIS IS A WORK IN PROGRESS - IT IS NOT YET FINISHED.

Ouch, I ordered for M5. I need M5 for my other parts. Can I just change the hole size without affecting the entire design? Thinking I just can drill it ...

Quote
Mogal
When it come to the extruded parts, its $16 a meter here. That's for 1"x1" (25mm profiles)
...
It's mostly awesome living on an island, but sometimes it really sucks.

Mogal
Why not contact [www.itemamerica.com] (the original's us branch)
(At least in Germany) They are used to fulfill small orders for sample "Maschinenbaumuster"
(they may hope for the BIG production order though)

We here in europe also have several "compatible" sources...
afaik zelogik and jand bought from motedis
[www.youtube.com]
...cdn isn't listed but they have very reasonable shipping cost (no broker)
[www.motedis.com]
...and don't you complain about taxes ;-)
(we here in eu are above 20% - which they substract shipping to you)

JAN I forgot... your parts were printed in PLA - correct?

Sorry, I don't have the CAD/Rendering skills as some of you around here
But this should be enough to get the idea across...
I've built a small enclosure for my CNC electronics and it works very well.

Still working on this, but I'm sure this would work and be rigid enough for the build.
Think of it as a tongue and groove set-up. The upper and lower plates will be 3/4"
and the side plates will be 1/4" the Tongues slide through the upper and lower
plates, and will then be bolted into place.
Still working with the upper section (needs a lid) and need to get the smaller details worked in...

I know MDF isn't the most desirable material to work with, but its supper cheap.



thanks for the suggestions regarding the extruded parts... but I really don't think I could make it happen

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

@mogal:

Nice design for a MDF frame. It looks like you want to place the motors on the outside. How do you plan your belt path?
I think it should be possible to use the plastic parts. You can bolt the corner pieces on the downside of the upper plate just like you would in the profiles. On the inside of the frame.

@reinhold:

No, everything is printed in ABS?

Edited 1 time(s). Last edit at 03/29/2014 04:53PM by jand.

@mogol: Jand have all right and same question as jand, what's your plan for the belt path with motor outside...? MDF can't be bad, but on island I think you have some humidity, so dimensions change, so don't hesitate to paint or put some resin on it, or it's will be painful for Z calibration.(like first makerbot or first ultimaker on humide "ground/land")
The link with video you have posted for the protoforge 3d printer is an HBot, there my plan and Jand's fork is a CoreXY system, not exactly the same things. Hbot is more simple to design but you need really tight tolerance free linear mouvement (really expensive) or you will have many cantilever/backlash problem. And with CoreXY, design is more difficult to be done( but there it's not a problem, I have already "brainded", engineered that for the community ;-)), but you can use really cheap linear bearing (lm8uu or igus), but need more pulley and two belts instead of one longer belt.

So you just need to modify a little bit each corner (only for the beauty of the thing not for the functionnality) for filling the part missing where the extrusion profile goes.

Yes reinhold ! please don't complain with TAX mogal , here in Europe Tax is very expensive and always more or less 20%, and I don't think Europe is a small island...

Finally yes your design is really nice for mdf, maybe you don't need to make a big windows for each plate, close wall is better for keep heat inside for ABS printing.



@Jand: Be careful with nickname, for me it's zelogiK and it's not mogol but mogAl :-D, and sorry to don't have respond to you, don't have time for see your plans.
Have you enought info/photos for limit switch?



@Reinhold, Chain cable wasn't so cheap finally ... 12€ for 1meter on ebay, the next time I will print it, I have seen many on thingiverse yesterday...

Edited 3 time(s). Last edit at 03/29/2014 05:24PM by zelogik.

Quote
zelogik
@mogol: Jand have all right and same question as jand, what's your plan for the belt path with motor outside...? MDF can't be bad, but on island I think you have some humidity, so dimensions change, so don't hesitate to paint or put some resin on it, or it's will be painful for Z calibration.(like first makerbot or first ultimaker on humide "ground/land")
The link with video you have posted for the protoforge 3d printer is an HBot, there my plan and Jand's fork is a CoreXY system, not exactly the same things. Hbot is more simple to design but you need really tight tolerance free linear mouvement (really expensive) or you will have many cantilever/backlash problem. And with CoreXY, design is more difficult to be done( but there it's not a problem, I have already "brainded", engineered that for the community ;-)), but you can use really cheap linear bearing (lm8uu or igus), but need more pulley and two belts instead of one longer belt.

So you just need to modify a little bit each corner (only for the beauty of the thing not for the functionnality) for filling the part missing where the extrusion profile goes.

Yes reinhald ! please don't complain with TAX mogal , here in Europe Tax is very expensive and always more or less 20%, and I don't think Europe is a small island...

Finally yes your design is really nice for mdf, maybe you don't need to make a big windows for each plate, close wall is better for keep heat inside for ABS printing.



@Jand: Be careful with nickname, for me it's zelogiK and it's not mogol but mogAl :-D, and sorry to don't have respond to you, don't have time for see your plans.
Have you enought info/photos for limit switch?



@Reinhald, Chain cable wasn't so cheap finally ... 12€ for 1meter on ebay, the next time I will print it, I have seen many on thingiverse yesterday...

Ok, I will check better next time, but check your last post as well.
I checked a few of my posts, and it seems I misspelled your nickname almost consequently, sorry about that.

Edited 1 time(s). Last edit at 03/29/2014 05:11PM by jand.

@Jand: No problem at all

it's a joke but In french we have an expression for what I have done just now... : "Fait ce que je dis, pas ce que je fais...." take it's easy it's not again you at all :-D

Hum...
$3 x 20% = $3.60
$16 x 13% = $18.08
LOL nope, you still win!
Joking aside I know you guys have a hard time with the taxes, it really sucks!

-----

As for my design, its a work in progress.
I'm still thinking it through, and watching you guys.

I will have spaces for the belts to pass through on the upper surface...
I'll post more pics when I get it designed in.

I do know I wont be using the cantilever design,
I'll have one 12mm rod and a threaded rod on each side of the bed(Left/right)

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

$16/meter ... yes really expensive for that 20x20mm profile... maybe because it's metric no?

The cantilever problem I have said is for HBot printer (the video you have posted) and X & Y axis.

Look between Hbot and CoreXY comparative. Sorry I don't found good link I have read on the net with explanation between Hbot and CoreXY.
Good resume...

Edited 1 time(s). Last edit at 03/29/2014 05:56PM by zelogik.

Oh sorry...
I understand the 'racking' problems with the HBot design.
the twisting of the X/Y axis during movements...

What I do not like is the cantilever design of the Z Axis (Lifting/lowering the bed)
I don't like the drive mechanism being on one side (just seems lopsided and unsteady)
I prefer the bed to be supported on two sides (Seems more stable)

My ultimate goal is to have a design like this
(Although I'm going to go with a dual Bowden setup)

But it has been you guys here driving me forward with the build!

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I got a little more done.
Hope this explains what I'm doing.
Trying to maximize build volume.
(The top will be solid - I left it clear for clarity)

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

@mogal

Nice work, I think your frame will be rigid enough when made from MDF. The only thing are the legs. I am not sure 1/4 inch ( 6mm) will be strong enough.
And you may want to connect the vertical plates at a few places to make it more rigid although I am not sure it will be necessary.

In your drawing I only see lead screws not vertical rods. I assume it is not yet in the drawing, you will need then.

Yes i have already seen that printer, the problem for me with the X and Y axis is ...(I'm not a engineering expert in mechanical BUT... i just love logic and have some basic in mechanics ). You have a big moment between X carriage rod, and X carriage belt fixation (the distance is really important). I don't know if somebody can understand me.

You play with the gap of bearing/flex of rod/deformation of plastic part, each time you tight or pull the belt with that distance between belt and rod alignement.

Now look on my design (I don't say alls design that it's not mine are horrible of course ) but you can see that there is no moment at all between belt and rod, each time you pull/tight the belt, the rod is on the same axis than the belt.

For the cantilever design of Z. the first time I have seen that, i don't like at all.. but after tested that with printed Z axis i loved it. Have a look at Ultimaker and Makerbot, both of them use that design and don't have problem with that. You just need to put big rod 12mm minimum AND don't have big one printer, 300mm is near to the maximum of length.

Today is a big day for me. My first github repository, my first opensource project.

I gathered all the files for my variant of Zelogik's design and put is in github.
I put it online so you all can have a look at what I have been doing the last months.
I did not put th STL files online. I want people to have a look at the design first, instead of starting to print without checking.

All parts are designed in FreeCAD, each part in it own file. I also made an assembly, wich you can find in the file src/core-XY.FCStd.
I did not make the assembly in FreeCAD. I don't think FreeCAD (me?) is capable of doing that at the moment.
So I used ViaCAD for that. So I exported alle files to STEP format and inported it in ViaCAD and moved the parts around in there. The result is in src/core-XY.vc3. This was exported again to STEP format and inported in FreeCAD again.

I have one issue open. Zelogik released the files with a GPL license I think. I don't think that is a good license for an open source hardware project.
So I released the files with a "Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)" license which I think makes more sense.
I think I can do that, because in the files I released are no files from Zelogic repository.

I don't want to upset Zelogik. And I want to make clear that my variant is based on his excellent design.

So please correct me if I cannot do this, or maybe: Zelogik do you want to change the license to "CC BY-SA"? Then there is no issue.

You can find the files here

Just to be sure I mention it again here. This design is not yet finished.

Yes cc by-sa 4.0 is more appropriate for hardware. As i'm the only contributor of my design i will update the GPL for CC one today

Just check my nickname on your github :-)

Finally congratulation for your first open source projection

Before my post checked for your nickname, but I missed the most imported one. The Title!!
I updated it a minute ago.

jand!
Thank you for the ViaCAD models!
I've had ViaCAD for over 2 years and still can't model like that
(Although I don't really spend much time with it)

zelogik,
Yes I know what you mean, and see that now. I will take that into consideration.
I may just revert back to entirely your design, but just use the MDF framing...
I have a lathe and mill as well, maybe I will make some parts from aluminium as well
Now to come up with 15 & 21mm ball nose endmills!

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

I have been following zeologic's build since he started this thread as I am exploring the possibility of building a form of HBot. As I am not totally convinced that I inderstand what is meant by "racking" I thought that this thread was the best place to ask for clarification - my intuitive guess is that a carriage with a large distance between rails and a short distance between bearings on each rail will tend to judder if the force is applied to one side. If I am wrong please correct me.

Further information: I want to build my next printer (my 4th) with multiple extruders and am not a great fan of bowden tube systems. Since more than three extruders is likely to have more mass than most table/model combinations it seems that the best way to go is with the table moving in both X and Y axis, but it is still desirable to keep the moving mass as low as practicable. My thoughts as the rendering below. The Y carriage has been omitted for clarity; but both the toothed idler and the fixed end of the loop would be connected to this Y carriage.



If my understanding of the racking problem is correct then this should work well - but please advise me if I am wrong.

Mike

Quote
leadinglights
... not totally convinced that I inderstand what is meant by "racking" I thought that this thread was the best place ..

Mike

Mike
The best place to learn about the theory is actually by visiting the author:
Ilan E. Moyer core-xy theory (*)
The main difference between what's called an "H-Bot" and the "CORE-XY"
is that an (annoying) twisting force (=raking,scratching)
is eliminated by the core-xy arrangement.
The force is negligable on sturdy setups nevertheless
for a light,nimble,fast 3D-printer may prove problematic.

A scribble (Jack_n) will explain the twist in kiss form:


Joshua Vasquez does theory and implementation in a more detailed form:
A brief discussion on overcoming drawbacks in an H-Bot design
If I remember correctly he also has references to You Tube vid's where you can actually see the twist.

Sorry to say but I need your Y Plate before I can undoubtly identify your design.
(Edit: Forget it YOU do have a H-Bot design! Look at the X-ing that a CORE-XY makes!)

Reinhold
(*) here sure is the place for a great implementation by zelogik (and soon in printed form by Jand) - Thanks guys!

Edited 2 time(s). Last edit at 04/03/2014 08:35AM by Reinhold.

Thanks Reinhold,
The scribble from Jack_n confirms what I guessed but I will look up the other sources that you quoted. I think that the narrow cross form should not suffer from racking - the very short length of belt is the main reason that I went for this form although the geometry makes it difficult to get the best X and Y travel in a small overall footprint. I am still playing off various ways of minimising mass and getting best rigidity but it is starting to look like I can get 200mm of Y and Y travel with less than 1.5kg of moving mass. Compliance yet to be calculated but looking good.

Mike

Edit: having looked at the corexy.com theory page, the corexy may work well for me in it's original incarnation - without the cross being moved to one end. I think that using fishing line or steel cable would allow this - possibly even GT2 belt with a fet liberties on twisting it.

Edited 1 time(s). Last edit at 04/03/2014 09:15AM by leadinglights.

zelogik & jand

Hey Zelogik, the more I look over your design, the more I like it.
I think I'm going to forget my design for the time being, and build yours!
(with the help of jand's STLs for printing)

Ultimately, I'd like to know if either of you have made any more progress?
It'd be great to see a couple more video's of things in action, and something being printed!

Cheers,
and once again, thanks for a great design!

---

--------------------------------------------------------
Custom all metal CoreXY
- Duet 2 Wifi w/ PanelDue 7i
- 330mm x 360mm x 500mm
- 750w Silicon heater

Custom Mendel90
(Backup printer - Old reliable!) - Sold

@mogal Not much progress, just a few updates on github. I made a FreeCAD script to generate the STEP and STL files. I am working on the Z axis at the moment. I somehow thought it was wise to move the Z motor to the bottom of the frame, but it does mot make sense. So it's back at the top again. The Z nut holder is designed (but not yet in github) I am still waiting for the LM12UUs. They were send twice to me, but returned to sender, because my address was unknown. (???) I now ordered somewhere else.

I am moving slowly, but will get there eventually. So many things to do, so little time.

Not so much time for engineering now. it's just click on print when I need to print .

But i need to make more modifications for the full enclosure. The bowden is too long (>1 meter) . So I need to thinking a way for put extruder motor on the moving carriage for the first extruder, and keep the second extruder with bowden cable. Or remove the cable chain and make like all bowden 3d printer.

EDIT: Yes I have found some waves/artifacts when printing. You need really round pulley OR maybe it's the current on the motor. I need to investigate on it.

Edited 1 time(s). Last edit at 04/08/2014 03:47AM by zelogik.

Quote
zelogik
... So I need to thinking a way for put extruder motor on the moving carriage for the first extruder,

Hi Zelogik
I'm not sure that's a good idea (for your corexy) ;-)
My measured weight data:
240g Nema17_40mm (1.7A,40Ncm)
340g Nema17_48mm (2.5A,48Ncm)
360g Airtripper + Nema17_40mm
470g (my)allMetal DirectDrive 40Ncm

I've just seen this one video of your corexy ...
Now my x-carriage runs on a StarRexrothBosch linear rail (at almost 60cm height)
The extruder on x-carriage is that homebrew all Metal DD 40Ncm & is "pound"-ing
With a good "resonating slice" the thing almost starts to walk

@Jan (maybe) try ebay 390791182791 (10pcs 12.59€, ship from GB, 3 days)
Why does "stepper at bottom" not make sense?

@Zelogik: You obviously wanted all moving stuff in one layer (at top)...
But would you disagree with turning your z-axis 180° (upside down)?

@Reinhold, Even if I put the Z axis upside-down, I don't have more space.

I always looking for put extruder in another place. Maybe just on the top of the X and Y motor. So I can shorthen the bowden tube to 800mm, not so bad.

Need to redesign the cable carriage support, AHHHH the joy of development

SPECIAL NEWS ... It's too late for me... I don't want too rebuild my printer.

@Everybody but specialy for @Jand if the Z axis is not already done

The XY carriage is always amazing, I don't see many downside or problems since the first print(for me ...), don't need to change anything. But for the Zaxis, put on the opposite side of the X and Y motor and like Reinhold have said, the motor upside down, on the bottom.

So :
- You don't have to make brush on the Z axis for make a total air tight enclosure. You put all the Z axis on the "half full enclosure".
- You have PLENTY of space for put INSIDE the printer: power, raspberry, ramps, 2 geared extruder (wade extruder or metal planetary gear), fan, whatyouwant.

The only downside is:
- You lose a little ratio for the printing size... or solution, need to design the screw and rod really well and normally you have "just" 30mm of space + almost 30mm for the nozzle. (I really think it's not so difficult to design.)
- Cables for Zmotor and Heater Bed are longer... put bigger wire as solution.


What's you thing?

Finished the Z-axis yesterday. Today I started playing with the bed moving up and down. It runs very nice. I am very happy. I have not tried yet, but it should be easy to mount the motor at the bottom and the bearing at the top. It is also possible to mount the Z-nut unit upsidedown.

It is in Github now. Just did a quick test in CAD for a upsidedown Z-axis. Have a look in test folder. and please advice which way to go. It's not yet made, but I will make a bearing at the bottom (or top) to contraint the leadscrew.

@jand:

It looks to me like a jack screw is pressing the corner bracket against the extrusion, is that what the manufacturer recommends?.
The heads of the bolts are all flush, and that is confusing me, so I'm unsure of how the assembly is constructed.

Got a link.