What's the secret of belts running inside aluminum extrusions Hi everyone ! I'm currently building a crane style printer (a cetus ripoff to be completly honest)... cetus-3d-printer.jpg mod_embed_images_loadimage('d20d06ae492ce326eafa057d75b8cf72', '/forum/thumbcache/bd2/23a/c55/b4e/fea/563/4cd/a8d/94d/f5b/74_800x400.png', 'https://www.3drap.it/wp-content/uploads/cetus-3d-printer.jpg', 'https://reprap.org/forum/addon.php?1,module=embed_images,check_scaling=1,url=https%3A%2F%2Fwww.3drap.it%2Fwp-content%2Fuploads%2Fcetus-3d-printer.jpg', '', 835448, 800, 400, 'Loading image ...', false); I know this is a flawed design (I mean cantilever... come on !) but I really like the compactness and minimalism of the overall machine... Anyway... I find quite amazing the fact that They are able to run the belt inside the extrusion and yet, connecting it to an MGN12 carriage... I've looked again, and again, and I can't quite find the way they do it... So if you have a drawing, a link to a commercial product that does it... or a picture of your Cetus i would love it ! (I was wondering if they use some kind of crimping connector like these one [openbuildspartstore.com] ) https://reprap.org/forum/read.php?1,835448,835448#msg-835448 Fri, 12 Jun 2026 17:04:08 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,835448,836210#msg-836210 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,836210#msg-836210
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MatthewHall
Archiclem... I built a printer in the design style of a Cetus. Here's the link to the respective forum thread. While I didn't put all the belts inside the extrusions, this might help. If you have any questions just ask.

Yes I know, I've built and printed some of the part you designed, but I really like the idea of belts running inside aluminum extrusions :) And I nailed it this Weekend, I will post some pictures and design file soon... And i'm kind of going the "all metal way", using printed part only where I can't get metal to fit :)]]> Archiclem General Mon, 15 Oct 2018 03:11:28 -0400 https://reprap.org/forum/read.php?1,835448,836191#msg-836191 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,836191#msg-836191 link to the respective forum thread. While I didn't put all the belts inside the extrusions, this might help. If you have any questions just ask.]]> MatthewHall General Sun, 14 Oct 2018 20:21:46 -0400 https://reprap.org/forum/read.php?1,835448,835655#msg-835655 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835655#msg-835655 with something 40mm long and gt2 idler pulley with 3mm hole you could use 2 holes on the rail one through the idler & plastic, and another 3mm screw in next rail hole. or with the 5mm example the block could be held with just one screw if it was butted up against the 2020 so it wouldnt rotate plus belt keeping it secure too.
[attachment 107485 untitled.283.jpg]
[attachment 107486 untitled.284.jpg]]]> MechaBits General Sat, 06 Oct 2018 09:13:39 -0400 https://reprap.org/forum/read.php?1,835448,835647#msg-835647 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835647#msg-835647
So no one on this forum has a cetus to take a look at ? It's so sad that the price has gone up like that on those nice printer, otherwise I would have bought one just to see how it's made !]]> Archiclem General Sat, 06 Oct 2018 06:47:34 -0400 https://reprap.org/forum/read.php?1,835448,835617#msg-835617 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835617#msg-835617 I had the belt running in 3030 in this version, but have since changed the profile for something else.

So now I have to redo hotend part & idler as the clearance has changed.
]]> MechaBits General Fri, 05 Oct 2018 15:46:56 -0400 https://reprap.org/forum/read.php?1,835448,835611#msg-835611 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835611#msg-835611 www.youtube.com]
As long as the machining is light then 3D printers do a good job but not to be confused with for-real milling.

Mike

p.s., perhaps we have moved this thread a bit far from it's origin so maybe need to discuss the limits of 3D printer milling in a new thread.]]> leadinglights General Fri, 05 Oct 2018 14:16:42 -0400 https://reprap.org/forum/read.php?1,835448,835609#msg-835609 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835609#msg-835609 MechaBits General Fri, 05 Oct 2018 14:08:21 -0400 https://reprap.org/forum/read.php?1,835448,835603#msg-835603 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835603#msg-835603 @MechaBits. The tooth profile was surprisingly easy, it was milled on a 3D printer with a Proxxon hand tool.With the hex screws about two turns loose the belt could be pulled up like a zip tie (click click instead of ziiip) and the few mm of movement used to fine trim so that the belt had a pleasant twang.

Mike]]> leadinglights General Fri, 05 Oct 2018 12:28:36 -0400 https://reprap.org/forum/read.php?1,835448,835600#msg-835600 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835600#msg-835600 MechaBits General Fri, 05 Oct 2018 11:39:22 -0400 https://reprap.org/forum/read.php?1,835448,835590#msg-835590 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835590#msg-835590
Clamps are so simple and reliable, I can't imagine a situation in which I would use anything else, but who knows, maybe some day I'll have to glue a belt...]]> the_digital_dentist General Fri, 05 Oct 2018 10:20:22 -0400 https://reprap.org/forum/read.php?1,835448,835583#msg-835583 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835583#msg-835583
MechaBits, I am assuming you are commenting on my photo in a posting above so perhaps I should clarify. The two plates form part of the tensioning mechanism and have grooves machined into the surface to grip the belt teeth as shown in the photo below. One of the plates is slotted to allow it to be moved before locking in place.

[attachment 107444 Plates.jpg]

Mike]]> leadinglights General Fri, 05 Oct 2018 09:11:00 -0400 https://reprap.org/forum/read.php?1,835448,835582#msg-835582 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835582#msg-835582
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leadinglights
No problems, I have had no failures in the belts on three printers. As I said though, toothed belt materials vary and rubber impregnated with a solid lubricant is is likely to have different adhesion to plain rubber. I would add to your comment though about jigs: It is useful not only to have a good cutting jig, but also a good assembly jig, especially with CA as the parts should be presented without any sliding movement and maintained under pressure until the bond has formed.

Mike

Of course, I made these jigs to cut and assemble.

Now, here here he doesn't need all this as it is for closed loop belts. Someone just suggested to use this kind of belt when in fact it is not necessary.]]> MKSA General Fri, 05 Oct 2018 08:50:52 -0400 https://reprap.org/forum/read.php?1,835448,835579#msg-835579 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835579#msg-835579 MechaBits General Fri, 05 Oct 2018 08:30:10 -0400 https://reprap.org/forum/read.php?1,835448,835578#msg-835578 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835578#msg-835578
Mike]]> leadinglights General Fri, 05 Oct 2018 08:21:48 -0400 https://reprap.org/forum/read.php?1,835448,835577#msg-835577 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835577#msg-835577 There are other techniques but requiring accurate jigs to cut interlocking profiles.]]> MKSA General Fri, 05 Oct 2018 08:05:36 -0400 https://reprap.org/forum/read.php?1,835448,835571#msg-835571 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835571#msg-835571
I glue my belts in this manner to run the back side of the belt over the idler pulley. I have gone away from using the twisted belt method, prefering to have one glued joint with the other ends held in a toothed tension adjuster - also back to back

[attachment 107442 Beltjoin2.jpg]

Mike]]> leadinglights General Fri, 05 Oct 2018 06:38:05 -0400 https://reprap.org/forum/read.php?1,835448,835557#msg-835557 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835557#msg-835557 The trick is to properly prepare the end and of course for a belt you don't glue end to end like an Oring !
CA is really good on rubber. Of course not for PU belt !]]> MKSA General Fri, 05 Oct 2018 02:07:17 -0400 https://reprap.org/forum/read.php?1,835448,835552#msg-835552 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835552#msg-835552 Trakyan General Thu, 04 Oct 2018 22:40:11 -0400 https://reprap.org/forum/read.php?1,835448,835531#msg-835531 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835531#msg-835531 etfrench General Thu, 04 Oct 2018 16:51:20 -0400 https://reprap.org/forum/read.php?1,835448,835483#msg-835483 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835483#msg-835483
I used this for the Z axis in UMMD and for the magnet carriage in a sand table:



No twisting needed. When you twist belts you may have problems with them riding on pulley flanges.
]]> the_digital_dentist General Thu, 04 Oct 2018 06:54:40 -0400 https://reprap.org/forum/read.php?1,835448,835476#msg-835476 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835476#msg-835476
There's plenty of room in the channel for the belt and a locking piece. The channel is 5.1mm wide, so the belt will need to be smaller than that if you want it to ride at the top of channel. You could also mill or file the channel wider to take 6mm belt (Wood routers and tablesaws handle aluminum fine, just noisy and a little more dangerous. Aluminum needs to more securely held than wood). If the belt is at the top of the channel, the locking piece can be 4+mm thick. If the belt will ride entirely in the channel, the locking piece would be 2+mm thick. The locking piece can be as long as the carriage, and that should be enough to secure the ends of an open loop belt. Personally, I'd use a closed loop belt.

p.s. I'm pretty sure 20x20 extrusion isn't going to be rigid enough.]]> etfrench General Thu, 04 Oct 2018 04:31:16 -0400 https://reprap.org/forum/read.php?1,835448,835469#msg-835469 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835469#msg-835469
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o_lampe
[attachment 107420 twisted-belt-M3.JPG]

Maybe this design of my 'compact carrier' helps understanding? It is designed for 'Bosch slot5' extrusions and works surprisingly well on my Delta. They are made of PETG, which allows me to tighten the belt without breaking the clamping part.

[attachment 107421 twistedbelt.jpg]

@o_lampe To connect open belt together in a 'twisted' fashion, I simply CA-glued them. That's strong enough, but only works on straights. No bending allowed.

this is very interesting indeed, but I have to questions, why would you need to twist the belt ? Is the friction not a problem ? What about the wear over time ? I never considered the fact that it could be a sliding part rather than a free "floating" connector.

@MKSA Yes that kind of what I have in mind, but I can't find a correct dimension piece of metal... I could try to fold one myself but that's another story...]]> Archiclem General Thu, 04 Oct 2018 03:17:14 -0400 https://reprap.org/forum/read.php?1,835448,835466#msg-835466 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835466#msg-835466 MKSA General Thu, 04 Oct 2018 02:21:39 -0400 https://reprap.org/forum/read.php?1,835448,835463#msg-835463 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835463#msg-835463
Maybe this design of my 'compact carrier' helps understanding? It is designed for 'Bosch slot5' extrusions and works surprisingly well on my Delta. They are made of PETG, which allows me to tighten the belt without breaking the clamping part.

[attachment 107421 twistedbelt.jpg]

To connect open belt together in a 'twisted' fashion, I simply CA-glued them. That's strong enough, but only works on straights. No bending allowed.]]> o_lampe General Thu, 04 Oct 2018 00:28:31 -0400 https://reprap.org/forum/read.php?1,835448,835459#msg-835459 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835459#msg-835459


@Etfrench (are you french ? cause I surely am...) It's the motedis I type extrusion from here [www.motedis.fr]

They give an STP file... For the moment I havn't been able to crack down this particular matter, for obvious reasons, the rail must be 90° from the running belt... Anyway the space inside the extrusion is verry small, and you have to solve the open loop problem here too.]]> Archiclem General Wed, 03 Oct 2018 20:01:17 -0400 https://reprap.org/forum/read.php?1,835448,835458#msg-835458 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835458#msg-835458
p.s. What extrusion are you using? Can you provide a 3d model of the extrusion?]]> etfrench General Wed, 03 Oct 2018 19:09:30 -0400 https://reprap.org/forum/read.php?1,835448,835457#msg-835457 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835457#msg-835457
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Archiclem
I know this is a flawed design (I mean cantilever... come on !) but I really like the compactness and minimalism of the overall machine...

There's absolutely nothing wrong with a cantilevered design as long as, like anything else, it is designed properly.]]> LoboCNC General Wed, 03 Oct 2018 18:48:03 -0400 https://reprap.org/forum/read.php?1,835448,835452#msg-835452 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835452#msg-835452
I've tried many design and the "clamping the belt" part is always the problem, too big for being a 3D printed part inside an extrusion (especially if you use open belt, because you have to overcome the tensioning forces that tends to rip your connector apart !)...

I've spotted this design [www.thingiverse.com] but it does not fit into my aluminium extrusion... And I was wondering how a commercial printer did it !

I don't know if that's more clear...]]> Archiclem General Wed, 03 Oct 2018 17:57:56 -0400 https://reprap.org/forum/read.php?1,835448,835451#msg-835451 Re: What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835451#msg-835451 the_digital_dentist General Wed, 03 Oct 2018 17:25:44 -0400 https://reprap.org/forum/read.php?1,835448,835448#msg-835448 What's the secret of belts running inside aluminum extrusions https://reprap.org/forum/read.php?1,835448,835448#msg-835448 Hi everyone !

I'm currently building a crane style printer (a cetus ripoff to be completly honest)...



I know this is a flawed design (I mean cantilever... come on !) but I really like the compactness and minimalism of the overall machine...

Anyway... I find quite amazing the fact that They are able to run the belt inside the extrusion and yet, connecting it to an MGN12 carriage... I've looked again, and again, and I can't quite find the way they do it... So if you have a drawing, a link to a commercial product that does it... or a picture of your Cetus i would love it !

(I was wondering if they use some kind of crimping connector like these one [openbuildspartstore.com] )
]]> Archiclem General Wed, 03 Oct 2018 16:58:10 -0400