Re: Printing Flexible Material with the MM is it posible
Hey Mohammad, what is the shore hardness of the TPU you are using, i had success with 98A and 95A no issues at all.
Also filament quality may cause issues like these. If the filament is not well extruded its diameter can vary a lot more than the specs and that does cause this type of jamming.
Peter
The shore hardness is 95A
https://www.sainsmart.com/sainsmart-1-75mm-1kg-2-2lb-flexible-tpu-series-filament-for-3d-printers-reprap.html
The filament looked very wavy to me though....
Maybe not all the sainsmart TPU filaments are created equal after all!
Also, is there a way to verify the settings I am using with slic3r multi material?
Re: Printing Flexible Material with the MM is it posible
Hey Mohammad, what is the shore hardness of the TPU you are using, i had success with 98A and 95A no issues at all.
Also filament quality may cause issues like these. If the filament is not well extruded its diameter can vary a lot more than the specs and that does cause this type of jamming.
Peter
The shore hardness is 95A
https://www.sainsmart.com/sainsmart-1-75mm-1kg-2-2lb-flexible-tpu-series-filament-for-3d-printers-reprap.html
The filament looked very wavy to me though....
Maybe not all the sainsmart TPU filaments are created equal after all!
Also, is there a way to verify the settings I am using with slic3r multi material?
Wow, if that is how the filament came off the roll, I would send it back.
One thing I noticed, if you use the latest slicer, check the retraction speed when printing flex. its the only speed thats set on the printer tab in slic3r and does not change when you select the flex material and print settings.
You probably need to change and save the printer config retraction speed down from the 80mm/s down to something reasonable.
Re: Printing Flexible Material with the MM is it posible
Yeah - i can confirm that Sainsmart TPU works great on the MM, printing together with ABS & PETG. Just slow down as usual with TPU. Just some stringing on first try because too less retraction (quickly modified the PLA defaults)
It would be great to see a preset made by the Pro´s in Slic3r 😉
To be able to select different printing speeds in Slic3r would speed up printing this combination a lot. Is it possible to put something like -50% speed on extruder 3 or per material in the settings?
Best
Christian
Would you mind listing your retraction settings and anything else you modified from the PLA profile? We've been playing with Sainsmart TPU for almost a week and are about to remove the MM upgrade so we can get back to printing (which was working fine before the MM conversion). Way too much stringing, which seems to be related to the poor retraction control of the Bowden system.
Re: Printing Flexible Material with the MM is it posible
I, too, am having loads of issues trying to get TPU to print with multiple colors.
Current attempt, three colors: Black (Hatchbox TPU), White and Red (Saint - TPU)
Issue: None of the filaments coming out of nozzle during prep phase of the print, or at anyu point thereafter (one color Might come out initially). After print is cancelled, one of the three colors seems to be suck in the nozzle (wont retract), as the other colors cannot be made to extrude through the end. Other colors come out with clean tips (they never reached the heating element). This reasoning is pure speculation.
I have tried nozzle temps of both 230 and 205 (both worked prior to the MMU upgrade). Limited movement speed to 15 mm/s and 20 mm/s, initial layer width at 150%, retract speed at 40 - 50 mm/s, retract length from 0.5 to 4mm.
If I just load one extruder with TPU and keep feeding it, it will eventually exit the nozzle. But once I have more than one color going on....it just gets stuck and nothing extrudes. Totally at a loss...mostly because there are so many different opinions on what settings work.
WOuld preally like to hear from Prusa regarding the settings they tested, assuming they got it to work with multiple TPU filaments.
Re: Printing Flexible Material with the MM is it posible
So, to what value can I reduce the length of the retraction?
Normal value for the MM is 4mm
Re: Printing Flexible Material with the MM is it posible
Just a thought here, it appears as if a few people have had success with TPU, I myself am not one of them. Was thinking about a potential way of maybe mounting a 5th extruder beneath the y splitter on the X-axis giving the system 2 points of contact which would both increase retraction capabilities of all filaments and make utilizing flexible materials much easier. I have noticed that overall, exotic materials are much harder to convince the printer to print with because the force at the nozzle is much less than it was when the extruder was directly above the nozzle.
Another fix may be to engineer up some mounting brackets and take one of the 4 existing extruders and mount it directly on top of the Y-splitter so that that one extruder can be used for all the filaments that have a hard time being pushed through the long tubing.
I personally like the first Idea of adding a 5th extruder that handles each material after the Y-splitter, allowing the other extruders to work in conjunction with it, basically making the material in the tubing slightly in tension instead of compression, giving control of the material back to the extruder at the very top of the nozzle and only using the other 4 extruders to push the material down to the 5th extruder between tool changes.
Re: Printing Flexible Material with the MM is it posible
Hello, Has anyone tried printing in Ecoflex PLA and soft PLA with MM?
http://makergeeks.blogspot.mx/2013/10/flexible-3d-printer-filament-now-in.html
Re: Printing Flexible Material with the MM is it posible
I wonder how hard it would be to add multiple extruders to the MK3? When I was looking at the MMU I thought it would be four feeders pushing to four extruders, but found I was wrong.
Today when I was researching dual-extruder systems I came across a link from E3D about their "Kraken quad extruder". It would be great if the Prusa team could integrate this into an upgrade, their MMU would work perfect to feed it.
Re: Printing Flexible Material with the MM is it posible
I'll chime in here with my experiences testing out various flexible filaments. In general anything softer than 95A seems to be too difficult to print with using the stock MK2/MMU bowden setup. I won't really post exact print speeds yet or anything because I'm constantly changing things depending on the model.
1. I find printing HOT seems to be the biggest determining factor against fighting jams. I'll sometimes even go 10C hotter than spec'd just because of the difference it makes.
2. Loosen the idle screws. If they are too tight it tends to deform the filament which causes it to under-extrude a bit.
3. Slow down the retraction speeds. I usually use something between 20-30mm/s. I've gotten some filament grinding with this too high.
4. Bridging speed of 1mm/s works miracles. Haven't needed support material so far.
What filaments do work?
nGen_FLEX (95A)
This stuff has the best look & feel by far and extrudes great but the biggest issue currently is getting it to stick to the build plate especially with thermal variance stress throughout the model. I ordered some Buildtak that should be arriving next thursday so I'm far from done with this material.
Generic Flexible PLA unknown hardness
https://filaments.ca/collections/1-75mm-3d-filaments/products/flexible-pla-filament-black-1-75mm
Inter-layer adhesion leaves something to be desired but the great thing about it is combines well with standard PLA for composite material builds.
What doesn't work (All of these have failed because they wind around the extruder gear)
-Generic TPE 90A
-Ninjaflex
I'll likely keep adding to this list as I test more materials and post pictures to go with it. I plan on testing Ninjaflex's Semiflex and Cheetah materials next.
Re: Printing Flexible Material with the MM is it posible
Hello,
I improved my extruder body of MK2 MM.
I am able to print of flex material ( TPE88 - RubberJet ) without stuck issues during the retraction or removing filament.
Change is that I prolonged the tubes up to extruder gears. Flexi filament has no chance to go between the gears
Re: Printing Flexible Material with the MM is it posible
Hi Martin,
Could you upload the STL file for this upgrade as I am having similar problems with flex on my Mk2S MM and would like to print flex, it worked before I fitted the MM kit and really don't want to remove it just to print flex again.
Many thanks,
Graeme