Rugged CoreXY

To be fair, when I looked up their indiegogo the claims for milling were very modest, targeting "Balsa, Foam, light wood". I guess that might work on an FDM motion platform, but it's not what I tend to think of when someone says milling

Don't like the jukebox look cosmetically, but quite a few similarities in my gantry design here.

[www.kickstarter.com]

On that printer the idlers on the Y axis are cantilevered. That is, they are not supported from both top an bottom. You see the screw comes through what looks like a 5mm plate and that and the clamping should hold the idlers in place.

I have come to believe that The Digital Dentist is right in his proposal where he supports all the idlers both top and bottom. It does make installation a bit more of a pain because you can't slip on the belts from on-top, but I believe it is the right thing and something I will myself be doing on all future builds.

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LarsK
On that printer the idlers on the Y axis are cantilevered. That is, they are not supported from both top an bottom. You see the screw comes through what looks like a 5mm plate and that and the clamping should hold the idlers in place.

I have come to believe that The Digital Dentist is right in his proposal where he supports all the idlers both top and bottom. It does make installation a bit more of a pain because you can't slip on the belts from on-top, but I believe it is the right thing and something I will myself be doing on all future builds.

Yes I did notice it was cantilevered, on a big plate too.

I also noticed the print fans blowing all over the hot end with no ducts of any sort.

Yes I'll be making a yoke of sorts for top/bottom support of all idlers. They're in thin ally too.

Edited 1 time(s). Last edit at 06/17/2016 07:54AM by hobbymods.

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LarsK
On that printer the idlers on the Y axis are cantilevered. That is, they are not supported from both top an bottom. You see the screw comes through what looks like a 5mm plate and that and the clamping should hold the idlers in place.

Got the belt teeth against a plain idler too ( just an observation).

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hobbymods
Don't like the jukebox look cosmetically, but quite a few similarities in my gantry design here.

[www.kickstarter.com]

Their goal is $84k and they're trying to develop a whole range of printers up to $7k? Hmmm.....

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

If their pitch is to be believed, the printers are already developed and tested. Looks like they want the cash to boot-strap the initial manufacturing costs. Can't help thinking that 7k euros is a pretty steep price tag. Hope those things are close to perfection. On the plus side, their example pom print is impressive - I'm nowhere with pom yet, need to get the enclosure done.

Their pitch really had little to be believed....

There was some guitar, some trendy european yuppies philosophizing about art and it's look and a whole bunch of general wankery, but hardly a spec or detail on the machine.

I think there was some awesome fabrication and potential there, but plenty of weak spots engineered into it and it seems a lack of priorities and direction.

Really seemed strange, but I was surprised to see my (or their lol) sheet metal/precision rail design concept there.

It just lacked the "rugged" bit.

Looks like I've missed a lot of discussion on these CoreXY machines, how come they get their own section and arent in the extruded alu section?

I bought a display case made of mostly 3030 extrusion for £23, so I now have 12x400mm pieces 4x2m 90deg curved sections
and 4 other pieces which are 30x60x400 'I' shape(like serif or V-slot) so if I dont build a 6ft machine, (as Z might need to be cable driven) I might be able to use these extra pieces as runners/guides for the bed, I have 3x330 linear rails, so almost ideal to fit in the 400mm envelope.(or maybe i'll get some more?) Plus it came with all the connectors. the 6030 'I' pieces could also be used to on the base section to give a little extra room underneath.

Is anyone here using the slots in the profile for mounting posts(shoulder bolts) for the bearings/pulleys, or is everyone using printed parts or metal plates to house the bearings/pulleys. (or are most trying to keep these areas unobstructed so its easier to enclose)

Also what about alternate belt arrangement, I'm thinking of a C shape for the Y(even if it means splitting into 3 belts), 3 corners of frame,
and a T shape for the X, 2 corners and the end of X, hopefully the two paths can be split, one on top of frame one underneath the top profiles. But maybe the problem with this arrangement would be the X trying to twist?

Also why is the ultimaker method of XY not being used, is CoreXY easier, or any better?(edit: read a little more MIT)
& another thing I've been thinking of a way to decouple Znut from the actual bed or X axis in other configs...
So far I have the 10.2mm brass nut end going into a larger 11mm brass/bronze bushing, with a thrust bearing sitting on the 22mm part of the brass nut....only problem so far is the standard 8mm brass nut for the leadscrew has the 4 holes for the 3mm bolts so the thrust bearing has to sit ontop of those bolts, but with a little redesign of the nut it could be improved...or perhaps with a little extra thought another solution to decouple the rotation/wobble, so the Z only does lift.

Anyone seen any other solutions? (edit: read a little more Mark One has the T shape and stiff X)

Horid Henry, campaign doesnt seem to be gaining much traction.

Edited 5 time(s). Last edit at 06/21/2016 09:31AM by MechaBits.

If doing stacked pulleys you could do like I just mocked up in this photo:

[goo.gl]

Depending on your profile the hole may be 6mm or bigger and then it may be strong enough to cantilever

I don't think you can get it strong enough with just a bolt in a drop in nut and the bearings on that bolt.

I have something similar on the end of my X arm on another printer, the bolt stays in place under tension and is easy to adjust tension but I haven't run it for any length of time, and could always be helped with other nuts either side in the trough.

Edited 1 time(s). Last edit at 06/21/2016 10:19AM by MechaBits.

I've been a bit slack, and also incurred the wrath of the "minister for finance" (and war....she has 2 portfolios) after she saw the bill for 3x 600mm ballscrews and all these other bits.

Here's a beginning of an extruder mount arrangement that incorporates the precision carriage, Bondtech extruder and genuine E3DV6 hot end with shroud/fan.

Horrible crap brown filament I use for prototyping until the roll is gone, but you get the picture.







Obviously I won't be using wood screws, and I'll turn the stepper motor plug to the same side as the fan cable, as well as a ptfe tube and cable guide. Little things like that.

Out of money for now, but will send a DXF drawing of the gantry plates to the water jet cutter.

Won't be able to buy my linear rails for a little while though.

Wow, those printed parts you have are so nice. I have seen a lot of printed parts on these forums, and it is usually only when people really really try hard they can make something like that... And you just made it for trial assembling...


The brown part that holds the fan, how did you print that? Support material? I am afraid that it will crack because you have the layers going in that direction and a thin square area where it comes out. Are you running high infill or what are your thoughts about that?

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LarsK
Wow, those printed parts you have are so nice. I have seen a lot of printed parts on these forums, and it is usually only when people really really try hard they can make something like that... And you just made it for trial assembling...


The brown part that holds the fan, how did you print that? Support material? I am afraid that it will crack because you have the layers going in that direction and a thin square area where it comes out. Are you running high infill or what are your thoughts about that?

Thank you.

That part won't crack, even in the cheap ABS I'm using there, and definitely not in PC or carbon fiber filament.

That's actually a medium quality print on high speed and 0.3mm layers and light infill.

The finished part will be in 0.2mm and medium infill.

I'm thinking a plug of some sort might be nice on the extruder mount.

I've got plenty of space out the back to extend the brown plate where it bolts onto the yellow faux linear carriage and fit a panel mount plug of sorts.

Even as I type this I see an issue if I solder them all into the back of a plug and then need to change a fan or something.

There are 10 wires shown, and there'll be 2 more for the print cooling fans. 12 wires.

I've worked with deautz and Cannon plugs in the past.

Any suggestions? I really hate seeing printers with a mess of wires floating all around the hot end.

A DB-15 is readily available
(the kind used for VGA connector on computer)



But a DB-25 may be better and use multi-pins
to carry high current of heater



All kinds of breakout boards for there connectors

High current for the hotend heater is definitely an issue with those connectors, easiest solution is indeed to bunch up multiple of them, although it could still slowly fail, when the connection isn't the best.
I had a double Molex KK connection (rated for 4A per pin, so 8A total) fail with 3A load, because the connections slowly degraded and it resulted in burnt plastic around it.
Positive thing about the D-SUB connectors of course is that they're lockable with the screws.

Edited 4 time(s). Last edit at 07/01/2016 03:54AM by Mikk36.

Something like this could be maybe a bit overkill, but looking at the list of prices it wasn't that bad compared to normal D-SUB connectors (assuming a selection of branded connectors, not noname ones).
[www.distrelec.biz]
[www.distrelec.biz]

More options here (active selection 2 high-current, 15 lower-current): [www.distrelec.biz]

For a one-off connection I don't find that too expensive.

Edited 1 time(s). Last edit at 07/01/2016 04:11AM by Mikk36.

Cheers guys.

Might be a bit like overdoing it, but I will at least not have crazy cables everywhere even without a plug.

Just "cooking" up a new extruder mount with fan shrouds and a cable tie fixing point.

I get how the plug works on that, but what cable will you use with that?

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LarsK
I get how the plug works on that, but what cable will you use with that?

Not sure.

Looking at it and many other printers, a big plug on the extruder just isn't feasible and would cause issues with simple repairs like changing a fan.

I'll just look at a neat way to anchor the conduit or cable chain so it's not a big mess.

Quite happy with the whole thing now.

A few little tweaks and cable routing mounts and it should be quite acceptable.

I'm really stuck for any spending at the moment, so things like this are cheap to do.

Going for a serious wooden look...







Edited 1 time(s). Last edit at 07/01/2016 07:36PM by hobbymods.

Have you checked to see if any air comes out of the fan nozzles? Axial fans don't work worth a damn against any sort of back pressure, and such nozzles create back pressure.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
Have you checked to see if any air comes out of the fan nozzles? Axial fans don't work worth a damn against any sort of back pressure, and such nozzles create back pressure.

Not yet, just a mockup that's similar to the Zortrax twin fan mod.

The shroud bolts on separate to the rest so I can try a blower fan as well....I'm assuming that's a better option?

To be honest I'd have an easier time fitting twin 40x40x20 fans to this shroud than trying to fit one of those snail shaped blowers...I'll do some testing and see what works when I'm closer to done.

Edited 1 time(s). Last edit at 07/02/2016 01:59AM by hobbymods.

Hey,

Looks really nice but seems a lot of work if you don't do pla printing. You for example said those parts you printed for the mock up is abs?

Are all those fans just for pla or is there something about printing I am completely oblivious to?

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LarsK
Hey,

Looks really nice but seems a lot of work if you don't do pla printing. You for example said those parts you printed for the mock up is abs?

Are all those fans just for pla or is there something about printing I am completely oblivious to?

Maybe....I like to use 20% fan for ABS printing as well. Helps with support removal and no noticeable loss of strength in the parts. Little nicer edges and definition in the parts as well (IMO).

The only reason these parts are being made in ABS is that I have an old roll of brown that's been laying around for 2 years. I've got a roll of odd PLA I'll probably use next if this roll runs out.

I wouldn't go to all this trouble to build a printer without a print cooling fan, as I plan to use various materials, not just ABS

Interesting.

I really only have experience with ABS. I never got into PLA. Giving up all the advantages of ABS just because PLA is easier and faster just seems wrong. Some time back a guy printing Nylon threw that exact same argument in my head

That said, my experience is that even an open window putting a breeze on the print can give radical different results. A continuous thin wall with some widths and heights is only possible if I reduce the speed to prevent putting too much material before the material has cooled down and settled.

For me the next step in 3d printing is making a heated enclosure to avoid those problems. Heating enclosure as a temperature regulated space that can reach above 60C.

Now you come an tell me you put 20% fresh air blowing on the print and you haven't with one word mentioned heated enclosure even as you talk about exotic materials I have yet to even see real life.


What is your thoughts about that? You haven't even mentioned putting enclosure on the printer?

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LarsK
Interesting.

I really only have experience with ABS. I never got into PLA. Giving up all the advantages of ABS just because PLA is easier and faster just seems wrong. Some time back a guy printing Nylon threw that exact same argument in my head

That said, my experience is that even an open window putting a breeze on the print can give radical different results. A continuous thin wall with some widths and heights is only possible if I reduce the speed to prevent putting too much material before the material has cooled down and settled.

For me the next step in 3d printing is making a heated enclosure to avoid those problems. Heating enclosure as a temperature regulated space that can reach above 60C.

Now you come an tell me you put 20% fresh air blowing on the print and you haven't with one word mentioned heated enclosure even as you talk about exotic materials I have yet to even see real life.


What is your thoughts about that? You haven't even mentioned putting enclosure on the printer?

I dont recall mentioning "exotic" filaments but can share my experiences with enclosures.

I simply dont print without an enclosure, and this printer will be fully enclosed.

I dont bother heating as well, I just rely on the heat generated by the printer itself to warm the enclosure to a nice 40-50 deg C.

I do use an exhaust fan with carbon filter on my existing printers, which I generally set at 45 for abs and 30 for pla.

That will probably trigger a bunch of opinions, but that's just the way I do it, not the only way. I do get quite reasonable print quality I like to think.

I tend to just aim for a stable temp throughout the print, and to stop drafts affecting the process as you have noticed yourself.

In winter my garage is down around 10deg C, at which point abs printing becomes difficult.

I heat my printer's enclosure the same way. It just happens to get to 45-50C from the bed heater. I discovered that when it was in my cold basement this winter it didn't quite get warm enough, so I plan to add a supplemental heater. I'll probably use the smoothieboard controller to regulate the enclosure temperature using an unused thermistor input and MOSFET output to switch the heater on and off.

I am designing and building a coreXY machine right now and like my other machine, it is being designed to be enclosed/heated from the start.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

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the_digital_dentist
I heat my printer's enclosure the same way. It just happens to get to 45-50C from the bed heater. I discovered that when it was in my cold basement this winter it didn't quite get warm enough, so I plan to add a supplemental heater. I'll probably use the smoothieboard controller to regulate the enclosure temperature using an unused thermistor input and MOSFET output to switch the heater on and off.

I am designing and building a coreXY machine right now and like my other machine, it is being designed to be enclosed/heated from the start.

While I wasn't planning to go as far as heating the thing, I have also considered using the board to control an exhaust fan.