Building a Kossel: Need advice on final parts

Hi!

I'm a Industrial Product Design student who has been looking into the RepRap scene for about a month now as I want my very own printer. I have experience with printing, but obviously not with making one myself. I've been doing research on a few different RepRap printers and I've decided to go for a Kossel cause of it's speed, which would be useful for rapid prototyping, and it's high quality prints. However, none of the existing Kossel kits that are out there on the market, appeal to me due to my limited price budget (maximum of about 600 EUR) or just not satisfied with the specifications of the kit. As a result, I've been working on my own (rather extensive?) part list for a few weeks now, with the goal to achieve the highest quality prints and the biggest print surface for about 600 EUR.

Right now, I've settled on a Duet board with nema 17 stepper motors with a stepping angle of 0.9° (running at 24V), a heated bed, auto calibration and most likely an E3D V6 hotend and V-Rollers for the linear motion. The remaining parts that I haven't decided on yet, are the extruder, the size of the aluminum extrusions, the rod ends for the carbon fiber rods and the print surface.

The current list of possibilities are the following:

Aluminum Extrusions:

• Robotdigg 2020 XL kit (3x 750mm for vertical, 9x 360 mm for horizontal) (are these compatible with V-Rollers?)
• 3x 1000 mm V-Slot 2040 (vertical) and 9x Misumi 500 mm 2020 (horizontal) (

Extruder:

• Delta Sextruder
• Flex3Drive
• Vaeder V-Struder
• 3Dator Bowden extruder
• Titan Extruder
• Wade's Geared Extruder

Carbon fiber rods (also depends on length of the extrusions)

• Traxxas rod ends
• Hayden's Magnetic rod ends

The full list of the part list are available on the following spreadsheet: [docs.google.com]

The cost for the preferred 500x1000 builds with magnetic rods is 488,16 EUR without shipping, printed parts and fans. I assume along with the shipping costs to Belgium (which are probably the next things I'm going to add to the spreadsheet) and the printed parts, the price will be bumped up significantly and I really want to keep the price below the 600 EUR. I'd like to add that I have acces to my school's Fablab incase I need to make a part myself. Feel free to give me your input on the choices I've made, the current choices I still have to make and maybe even alternatives to some of the current options I've found.

Edited 1 time(s). Last edit at 01/26/2017 04:27PM by Riggi.

Given your budget, in your position I think I'd buy the Robotdigg 2020 kit less electronics and hot end, and add the Duet electronics and E3D hot end. The Robotdigg vertices and carriages work very well - I use them on my 1m high 2020 delta. I don't know how good the Robotdigg rails are because I haven't trîed them.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

That is another possibility indeed. I'll do some searching to see if the Robotdigg rails are good enough or not and assemble a list for all the Robotdigg parts without the electronics and hotend. Do you happen to know wether or not the Robotdigg extruded profiles work with V-rollers or are the linear rails in general better than the V-rollers? I've read a lot of mixed thoughts about V-rollers so far.

too expansive
you will have huge duty taxes!!
it s cheaper to build yourself and you should read dc42 blog
i learn a lot with his blog!

Yeah it is possible that the Robotdigg one will end up expensive. I think that building one myself would indeed be the cheaper solution if taxes and shipping don't make it too expensive. I've checked the DC42 blog before, but I'll check it again.

all parts that you need are in europeen union and for the others you will never had duty taxes because it s small parts
extrusion is cheap on montedis shop (you will have less than 60euro with shipping cost for a complet kit..)

That's true. I'll look around where I can get the parts in the EU as it would probably be cheaper.

Thanks for the suggestion!

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Riggi
That is another possibility indeed. I'll do some searching to see if the Robotdigg rails are good enough or not and assemble a list for all the Robotdigg parts without the electronics and hotend. Do you happen to know wether or not the Robotdigg extruded profiles work with V-rollers or are the linear rails in general better than the V-rollers? I've read a lot of mixed thoughts about V-rollers so far.

The general opinion seems to be that good-quality linear rails are best, but good-quality wheeled carriages beat poor-quality linear rails. My delta is working well using wheeled carriages on ordinary (not V-slot) 2020 extrusion, but I'll probably try linear rails at some point.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
Riggi
That's true. I'll look around where I can get the parts in the EU as it would probably be cheaper.

Thanks for the suggestion!

The most expensive parts are the Robotdigg vertices. IMO these are also some of the most important parts to have. I recommend their carriages with integral belt tension adjustment too.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Okay thanks dc42! I'll see if I can get my hands on some good linear rails instead then.

I've also found an alternative to the Robotdigg vertices, which are these metal brackets [www.amazon.com]. Do you think they offer the same stability to the build like the Robotdigg ones? The robotdigg carriages really look like a clean solution for an open belt but are they really that much better compared to the 3D printed variants?

Just to throw in my two pennies worth - I have not encountered "bad" linear rails. Some Chinese ones arrive and are a bit notchy at first. Remove the carriage, over a tray to catch the bearings. Then degrease the rail and carriages, paying attention to the slots on the sides of the rail where the bearings run. Regrease them with lithium grease or similar and plenty in the carriages too. Now check the bearings visually discard any obviously wrong sized ones, (the MGN-12H bearings are 2.35mm approx. but you have to buy them as imperial they are 3/32inch) and replace them leaving a gap of one bearing. Reattach the carriages they should slide smoothly. Don't mix carriages keep the same one with the rail it came with (or at least mark them so if you do decide to swap them around to see if they run smoother you can go back).

This might sound like a lot of hassle but the cost differential is huge.A Japanese rail would be £150 but works beautfully out of the box, a chinese one £20 needs a bit of tweaking. I have three printers running with these Chinese rails and they are extremely successful. My large kossel calibrates to 0.02mm deviation.The other option is to see if you can salvage a high quality rail from somewhere, if you can that's great but I could only find one nearby vendor with a 3m rail and one carriage so I'd have had to buy two genuine carriages.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

[docs.google.com]

look this for the best linear guide(industrial quality)

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Riggi
Okay thanks dc42! I'll see if I can get my hands on some good linear rails instead then.

I've also found an alternative to the Robotdigg vertices, which are these metal brackets [www.amazon.com]. Do you think they offer the same stability to the build like the Robotdigg ones? The robotdigg carriages really look like a clean solution for an open belt but are they really that much better compared to the 3D printed variants?

this vertice are not available for eur country..
does this version inclued Top Idler ?
[www.robotdigg.com]

where we can buy this idller in spare parts?i can t arrive to find them..

Alright it's good to know that even the cheaper linear rails do work as well after some greasing, thanks! Does anyone know if the linear rails make a lot of noise or are they relatively quiet?

I don't seem to have acces to the google document so I can't check it out titeuf007. Yeah the vertices aren't available through amazon, but apparently you can contact the guy who made them here in the deltabots group discussion [groups.google.com]

I don't think the idlers are included with the robotdigg vertices but I'm not sure about it.

The rails do not make any noise at all that I can hear, with Duetwifi and high microstepping, I can hear my hotend fan more than any other component.

Titeuf007

Couple of things strike me about your build list:

E3d v6 direct - you will surely want a bowden version, even if you use flying extruder there is still a bowden tube. Plus if you buy bowden and go direct no problem.

The brackets I bought which were the Chinese copies of robotdigg, had idlers for 6mm belts with them.

The horizontals at the base 6x 2020 works as it leaves you a 20mm gap for wiring etc...
For the top horizontals given your printer's size I would buy 2040's.

Igus rails are probably very nice but I've not come across many people using them on 3d printers, and they will have more friction when starting from stopped than versions with ball bearings.

Edited 1 time(s). Last edit at 01/28/2017 07:22AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Looks like they reduced the price of the aluminium vertices, which is good. Time to upgrade my 2020 printer to 2040 I think!

When I bought my 2020 corners from Robotdigg, the idlers were included. However, they are smooth idlers, and toothed ones would be better.

I used 2060 extrusion for 2 sides of the bottom triangle for extra rigidity. The third side is 2 x 2020 so that I can fit the mains inlet connector, SD card slot etc. See [www.thingiverse.com].

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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DjDemonD
The rails do not make any noise at all that I can hear, with Duetwifi and high microstepping, I can hear my hotend fan more than any other component.

Titeuf007

Couple of things strike me about your build list:

E3d v6 direct - you will surely want a bowden version, even if you use flying extruder there is still a bowden tube. Plus if you buy bowden and go direct no problem.

The brackets I bought which were the Chinese copies of robotdigg, had idlers for 6mm belts with them.

The horizontals at the base 6x 2020 works as it leaves you a 20mm gap for wiring etc...
For the top horizontals given your printer's size I would buy 2040's.

Igus rails are probably very nice but I've not come across many people using them on 3d printers, and they will have more friction when starting from stopped than versions with ball bearings.

it s just that no people know them
[www.igus.be]

it s industrial grade quality
a complet set cost 100euro vs 60usd(without taxes and shipping cost) for chinese...
djdemond: if i understand:
i need to order 3 vertical 2040
6 2020 for the horizontal base
and 3 2040 for the top?what kind of screw do i need for 2040?

for the extrusor i don t know yet what i want and what is the best for this size...if someone has an advice

Okay it's good to hear that they barely make any noise. The 3D printer would be put in my room and I wouldn't want it to be very noisy all the time.

And oh so that's why you have so many different extrusions in your part list dc42. When I went over it, I was confused as to why you had that many different sizes of extrusions. It all makes sense now and it's pretty neat! Also, at what kind of size would you recommend 2040 extrusions over 2020 extrusions for the vertical extrusions? The Robotdigg XL vertical extrusions are only 2020 and are 750mm long and I'm not sure if they'll be sturdy enough.

I run a 20mm nema 17 motor with e3d titan (1.75mm filament but this goes without saying these days) no issue and the whole assembly weighs just 290g. I have mine as a flying setup.

I think David makes a good point that 2 of the lower horizontals can be 2060 which would increase rigidity of the frame.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Just be careful with the RobotDigg toothed idlers. I bought 4, and one had so much runout it was completely unusable. You could see that the hole was offcentre just by looking at it. Maybe the intern was drilling the holes that day.

Buy a few more than you need.

The smooth idlers are okay for a large printer. If the noise or theoretical reduction in accuracy of the teeth on the smooth idler bothers you; you wouldn't necessarily have to have your endstops right up to the idlers, so you could twist the belts and run them back side onto the smooth idlers (having 700mm of build height is great but realistically your almost never going to use it, and even then 690mm is still plenty for example).

Be interested to see how the igus rails work I did consider them but decided against.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
Riggi
Okay it's good to hear that they barely make any noise. The 3D printer would be put in my room and I wouldn't want it to be very noisy all the time.

And oh so that's why you have so many different extrusions in your part list dc42. When I went over it, I was confused as to why you had that many different sizes of extrusions. It all makes sense now and it's pretty neat! Also, at what kind of size would you recommend 2040 extrusions over 2020 extrusions for the vertical extrusions? The Robotdigg XL vertical extrusions are only 2020 and are 750mm long and I'm not sure if they'll be sturdy enough.

When I build my delta, Robotdigg only sold the 2020 vertices. If I was starting now, I would use 2040 because the extra cost is small. I haven't had any issues that I can blame on using 2020 instead of 2040.

Edited 1 time(s). Last edit at 01/28/2017 10:36AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

Quote
Riggi
Okay it's good to hear that they barely make any noise. The 3D printer would be put in my room and I wouldn't want it to be very noisy all the time.

And oh so that's why you have so many different extrusions in your part list dc42. When I went over it, I was confused as to why you had that many different sizes of extrusions. It all makes sense now and it's pretty neat! Also, at what kind of size would you recommend 2040 extrusions over 2020 extrusions for the vertical extrusions? The Robotdigg XL vertical extrusions are only 2020 and are 750mm long and I'm not sure if they'll be sturdy enough.

When I build my delta, Robotdigg only sold the 2020 vertices. If I was starting now, I would use 2040 because the extra cost is small. I haven't had any issues that I can blame on using 2020 instead of 2040.

great to hear
what do you recommand for belt? does it better to use 9mm widh instead 6mm belt?
for large delta i will be more logical to use larger belt..but perhaps it s not true

do you think it s good calculator
[docs.google.com]

Edited 1 time(s). Last edit at 01/28/2017 10:51AM by titeuf007.

Okay thanks for the warning on the idlers nebbian!

Yeah I suppose the rigidity would be great indeed with 2 2060 horizontal extrusions DjDemonD. I have seen your flying extruder on thingiverse. It looks really nice, but the only thing that worries me with a flying extruder, is that the extruder can be swinging around a lot when it moves quickly. Does it bother you that it can move this freely or aren't you worried at all about using a flying extruder?

Good to hear that you didn't have any issues with using 2020 over 2040 extrusions David. I'll see how big I can go with my limited budget I suppose. I have calculated how much it would cost on average to buy the Robotdigg parts without the electronics and the hotend and buy a duet and E3D V6 along with a titan extruder, and the pricetag was actually doable (about 570 EUR with most of the shipping costs and taxes).

I'm still rather picky about the carbon fiber rod ends. I've read some mixed results about magnetic joints in general, but actually quite a lot of good stuff about Hayden's magnetic joints. Sadly they are quite expensive and I don't think they will fit on the Robotdigg carriages. I've read on your blog David that you're using Igus joints over the Traxxass joints. Are they a big improvement over the Traxxas joints or do you think it's better to go for a different kind of joint?

Flying extruder is a no-brainer. If you put slight downward tension on it with the bowden tube it wobbles less. Nebbian came up with a shock absorber design which works better on larger printers where the elastic element has to be much longer.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I've just checked out the damper design from Nebbian and wow this is a really nice design. The flying extruder barely wiggle at all, compared to a flying extruder without dampers. I'm pretty sure I'll go for a flying extruder now!

I was thinking of using rc car shocks there is a 170mm version available.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Quote
Riggi
I'm still rather picky about the carbon fiber rod ends. I've read some mixed results about magnetic joints in general, but actually quite a lot of good stuff about Hayden's magnetic joints. Sadly they are quite expensive and I don't think they will fit on the Robotdigg carriages. I've read on your blog David that you're using Igus joints over the Traxxass joints. Are they a big improvement over the Traxxas joints or do you think it's better to go for a different kind of joint?

Traxxas joints are easier to use than Igus. However, some of mine had a little play in them. So I recommend getting 2 packs of 12 joints, assembling them all using the hot/cold method, then pick 12 joints with no play to make into rods. Make the rods one by one, on the same jig. Even using slow-set epoxy, you can turn around 6 rods in 2 days.

I have a set of Haydn's rods on order. I plan to use them with a PCB effector and PCB carriage adapters that I am developing jointly with T3P3, that will work with my Robotdigg carriages. I'm toying woith the idea of upgrading to 2040 extrusions and linear rails at the same time. But right now it's Chinese New Year, so Robotdigg are not shipping and my PCBs are held up.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

RC Car shock dampers would also do the trick I suppose!

You would have to write quite a big upgrade blog if you switch to Haydn's rods, 2040 extrusions and linear rails. You have piqued my interest more with these PCB effector and carriage you're developing with T3P3 though! I'm curious as to what those will be like and what they'll do. Isn't there a possibility that the "PCB effector" could be damaged cause of the heat the hot end is generating?

Indeed with the Chinese New Year a lot is on hold right now. I was hoping to get all my parts together so that I have everything till the end of the exams (which would be wednesday) but the exams have put me on hold more than the Chinese New Year has.

Also someone over at the deltabots group recommended an alternative that I should consider picking up the BI V2.5 frame someone is selling over there. They appear to be very sturdy, so I suppose this could be the replacement for the metal corners from Robotdigg, but first I need to know what is in this frame exactly because he is selling it for $250. Now I wait till I get some more information about this frame. Does anyone happen to have any experience with these BI V2.5 delta printers?

Those Amazon corners can be a pain in the Axxx to assemble and are in no way as good as the Robotdigg ones that is why my big delta still isn't finished.

I would go for the Robotdigg corners and match them with OpenBuilds Extrusion which is proper Vee-Slot stuff if you are going to use rollers or stick with Motedis for std extrusion if using Linear Rails.

I can also recomend Haydn's Mag ball rods especially if you opt for the optional Delrin ends.

Doug