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gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: CybrSage

If you are near a Lowes or Home Depot, the smallest size black ties are a great fit.

Probably where I got these. They've been in the tool chest for at least 10 years, maybe closer to 20. Joys of having to buy a bag of 100 when all you needed was 2 or something 😆 

MMU tips and troubleshooting
Posted : 01/08/2019 6:21 pm
CybrSage liked
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

Yeah, mine has a lot less hours on it. I've split the workload between it, and two other printers, for PLA. I'm sort of retrofitting the A8 to do some PETG stuff right now, so it's offline. Heated bed needed a lil more oomph than it could deliver. Also using a bigger power supply on the A8.

I've not had many jam issues, but...I also don't use HTPLA, which I hear jams like crazy.

Posted : 01/08/2019 6:22 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S

This wasn't HTPLA. It was actually the silver PLA that Prusa used to sell before starting Prusament. I was doing near continuous multi-day 0.05 layer prints for about 30 days straight. Finally on my last plate it got about 30% through and jammed up good. Went through 4 attempts until I now don't have enough of the filament to finish it. I was able to run the print fine with a different PLA though using the same gcode. So whenever I get back to that project I have to throw about 120 hours of printing out and redo it since I'm not paying $12-15 for shipping on a $25 spool of filament.

Then after that frustration I spent 3 weeks getting my first multi-color MMU print to come out. I've been a bit off of printing since then and the printer now sits idle more than not. I've partnered with another forum member to work on a purge bucket and that has me excited about printing again (just in time for it to jam and screw up the extruder 🙄).

MMU tips and troubleshooting
Posted : 01/08/2019 6:35 pm
Casey liked
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

Yeah, I certainly did not expect them to melt, coming from Prusa themselves.

Posted : 01/08/2019 6:41 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat

This wasn't HTPLA. It was actually the silver PLA that Prusa used to sell before starting Prusament.

That silver PLA was one of my favorites, actually. I do remember having to run that stuff a wee bit hotter than profile for good results. Then again, I was on a copper block and nozzle.

Posted : 01/08/2019 6:43 pm
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

This purge bucket tou mention sounds interesting.

Posted : 01/08/2019 6:44 pm
vintagepc liked
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat

I've partnered with another forum member to work on a purge bucket and that has me excited about printing again (just in time for it to jam and screw up the extruder 🙄).

So on this purge bucket, e3D had tried to do a purge vacuum. Then there's one with a brush that the nozzle goes across (though Nozzle-X's warranty forbids wire brushing due to the coating).

I'm working on ideas to put other super-hard coatings on nozzles with someone, but gotta get him some nozzles to test with.

Posted : 01/08/2019 6:50 pm
vintagepc
(@vintagepc)
Member
RE: I challenge Prusa to use MMU2S
Posted by: CybrSage

This purge bucket tou mention sounds interesting.

https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2

Still very much a WIP, but getting there.

Posted : 01/08/2019 6:51 pm
CybrSage and gnat liked
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O
Posted by: gnat

This wasn't HTPLA. It was actually the silver PLA that Prusa used to sell before starting Prusament.

That silver PLA was one of my favorites, actually. I do remember having to run that stuff a wee bit hotter than profile for good results. Then again, I was on a copper block and nozzle.

😒 The block I ordered for my rebuild this weekend is a copper one... I thought it was supposed to warm a bit faster and hold the heat better than the aluminum block...

Yeah I loved that color and can't find an alternative that (otherwise) prints as nice and looks as good. PushPlastics has a silver that is close, but not a match so I'm given that a try. I'm hopeful since the sell .5kg master spools in a good range of colors and they are more local than going over the ocean.

MMU tips and troubleshooting
Posted : 01/08/2019 7:00 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: vintagepc
Posted by: CybrSage

This purge bucket tou mention sounds interesting.

https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2

Still very much a WIP, but getting there.

Specifically here is a 3DBenchy test and purge comparison: https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket/tool/3DBenchy

Please no laughing at the Python code. It was a brute force approach to the POC. I really am a professional programmer that writes far better code 😆 

MMU tips and troubleshooting
Posted : 01/08/2019 7:03 pm
CybrSage liked
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat
Posted by: Casey/NZ2O
Posted by: gnat

This wasn't HTPLA. It was actually the silver PLA that Prusa used to sell before starting Prusament.

That silver PLA was one of my favorites, actually. I do remember having to run that stuff a wee bit hotter than profile for good results. Then again, I was on a copper block and nozzle.

😒 The block I ordered for my rebuild this weekend is a copper one... I thought it was supposed to warm a bit faster and hold the heat better than the aluminum block...

Yeah I loved that color and can't find an alternative that (otherwise) prints as nice and looks as good. PushPlastics has a silver that is close, but not a match so I'm given that a try. I'm hopeful since the sell .5kg master spools in a good range of colors and they are more local than going over the ocean.

Warm faster, nope, hold heat, yep, ish. Depends on your feed rate. I think the only way to get around that is a Volcano, probably. Tempting...

I've started to get really happy about the Silk gold/blue/silver/copper etc colors.

Posted : 01/08/2019 7:08 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat

https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2

Still very much a WIP, but getting there.

Specifically here is a 3DBenchy test and purge comparison: https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket/tool/3DBenchy

Please no laughing at the Python code. It was a brute force approach to the POC. I really am a professional programmer that writes far better code 😆 

Hehe, I write no python. So there's that.
I'm an amateur programmer, formally trained in COBOL 2000 with a COBOL 85 compiler, and I have  to tell professional programmers how to do SQL things. 😉 Not a fan of outsourced app dev right now. (shhhhh!)

I might give that a try sometime, for kicks... once the dust/mayhem settles...

Posted : 01/08/2019 7:11 pm
vintagepc
(@vintagepc)
Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O
Posted by: gnat

https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2

Still very much a WIP, but getting there.

Specifically here is a 3DBenchy test and purge comparison: https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket/tool/3DBenchy

Please no laughing at the Python code. It was a brute force approach to the POC. I really am a professional programmer that writes far better code 😆 

Hehe, I write no python. So there's that.
I'm an amateur programmer, formally trained in COBOL 2000 with a COBOL 85 compiler, and I have  to tell professional programmers how to do SQL things. 😉 Not a fan of outsourced app dev right now. (shhhhh!)

I might give that a try sometime, for kicks... once the dust/mayhem settles...

More testers always welcome! 🙂

Posted : 01/08/2019 7:20 pm
Casey and CybrSage liked
bobstro
(@bobstro)
Illustrious Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O

[...] Kinda wondering though, how come we had Prusa blaming enclosures on the other issue with hot fins, yet they had someone developing an enclosure with lack tables. Makes one think "hmmmmm"

Side diversion: I think that was a case of "let's do something fun" turning into "oh, didn't think they'd do THAT with it." IIRC the Lack blog article landed in April 2018 and response was huge. Lots of attention and everybody seemed to be building one, including non-Prusa owners. Then the (then) record temps of summer hit and reality met PLA. I was a bit surprised when a guy from Singapore mentioned that room temps in his home are regularly 40C. In fairness, I do see some enclosure-related heat issues discussed in PLA discussions with other printers. I suspect Prusa regrets that blog post now. They do seem to have updated it with some PLA temp warnings.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 01/08/2019 7:47 pm
Casey liked
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O
Posted by: gnat

https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2

Still very much a WIP, but getting there.

Specifically here is a 3DBenchy test and purge comparison: https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket/tool/3DBenchy

Please no laughing at the Python code. It was a brute force approach to the POC. I really am a professional programmer that writes far better code 😆 

Hehe, I write no python. So there's that.
I'm an amateur programmer, formally trained in COBOL 2000 with a COBOL 85 compiler, and I have  to tell professional programmers how to do SQL things. 😉 Not a fan of outsourced app dev right now. (shhhhh!)

I might give that a try sometime, for kicks... once the dust/mayhem settles...

For the record, I despise Python. For writing it for so long, however, my Perl skills have gotten too rusty and Python is far easier to hack through a PoC like this than Go which is what I've started writing the real tool in.

MMU tips and troubleshooting
Posted : 01/08/2019 7:51 pm
Casey liked
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

Other than freeing the space lost to the wipe tower, does the bucket do anything else for you?

Posted : 01/08/2019 8:01 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: CybrSage

Other than freeing the space lost to the wipe tower, does the bucket do anything else for you?

A lot depends on the object being printed. There is a lot of printing to the tower that is simply maintaining the tower for when a color change is needed. That eats both time and material and we can easily remove that from the gcode. So, for example, if you have a 40mm tall print and the first tool change isn't until say 38mm, you have 37.xmm of tower that is pure waste. In both filament and time. Thus we see for my Benchy test that we cut the purge volume by more than half (we everything is tweaked out correctly and there is no bleed I expect it will probably be closer to half).

Similar to the outgoing filament, there is extra filament being laid down on the tower after the actual purge volume has been completed, so that is some more time/material that can be saved.

Because we aren't building to the tower, that should also help us save time as well. This was shown in early testing of a 8mm tall object with one tool change at 4mm. The print time went from 13 minutes to 9 minutes. This did not play out with Benchy where we actually added 2.5 hours (9 vs 6.5 hours), but I believe that is still just a matter of tuning the travel and extruder speeds.

MMU tips and troubleshooting
Posted : 01/08/2019 8:17 pm
Casey and CybrSage liked
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

Gack!  You are right!  I had not thought about that!  Nice!  I am going to keep my eyes on this.  Once I get the MMU2 working mostly flawlessly, I will smile, nod my head, and dive into this, which will most likely cause me problems.  🙂

Why sit on my laurels with a fine tuned machine when I can tinker with it and make it troublesome again?

Posted : 01/08/2019 8:19 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S

Actually @vintagepc came up with a great design on the bucket so that you don't have to modify anything. You remove your right Z stop so you can lift the guide rod, slide the bucket mechanism up to the Z carriage, screw it on with a built in compression mount that uses an open area on the carriage, slide the rod back down, and reinstall the Z stop. Done with the printer on and steppers engaged you don't even need to recalibrate. Then after promptly breaking my bucket he came up with a modification to allow for changing the bucket without having to remove the whole mechanism.

Better still, as long as you have the spring/rubberband installed to pull it back out of the way, you can do normal printing just fine.

Interestingly the BigBrain3D bucket appears to have a similar design where it hangs off the Z carriage out of the way when not in use. That is supposed to be showing up on Thingiverse at some point, but we're still waiting...

MMU tips and troubleshooting
Posted : 01/08/2019 8:37 pm
Nikolai
(@nikolai)
Noble Member
RE: I challenge Prusa to use MMU2S

My biggest concern is adding more complexity to already pretty complex system make it less reliable. The current tower solution is more or less fool proof. Yes, it eats some time and a little bit filament but you don't have to change anything special in Slicer or gcode. I'm just using my regular MMU work flow.

I remember 3DP Noob tried that concept and it didn't look like a perfect solution to this problem.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 01/08/2019 9:36 pm
CybrSage liked
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