MK3S part melted  

RE: MK3S part melted

Thanks. That was just the info I wanted on the x-carriage.

ABS gives you a fighting chance, but it is messed up that the R4 extruder configuration can much damage itself so badly.

BTW, your picts actually are correct AR when viewed on my phone, but not my laptop. This new forum is cleverly messing it up on the fly.

RE: MK3S part melted

I have news from Prusa Customer Support:

They are aware of the problems and are working on fixing them.  A rework should be available in a week or two.

Well that sounds rather promising to me. We will see!

RE: MK3S part melted

Awesome... They kept saying "it will be a long time, it's low priority" to me earlier. I guess the wheels had to squeak loud enough, and in great enough numbers.

RE: MK3S part melted

That's good news indeed.

Let's hope that they catch this occasion and also introduce the fixed filament path and a couple other upgrades since they have a new revision in the barrel.

I still wish they would print the more critical parts of the extruder in ABS at least, but i realize that keeping a part of their farm at 40-50C might be a hindrance. The fan shroud is already in ABS but i guess they can get away with printing such a small piece at the usual 35-40C they use in the farm.

RE: MK3S part melted

Well....I just got off of chat support after another 3 hours... of troubleshooting, doing backflips, etc..... about the melty part, the mmu2 issues... Feels like we danced around the topic I was really wanting to get addressed... that being, getting ONE print out of this thing. Not even multi-material. Just...one... little... print.

The guy working with me suddenly said "Ok my shift's over," tosses me to someone, and the chat is immediately DUMPED in the middle of sending pictures the previous guy asked for.

It has been 3 weeks since I've had this thing work as intended, thanks to the MMU2S downgrade. My Anet A8, AND the 2012 Makerfarm i3v that I took in for repair BOTH work better than this $800+300 Original PRUSA, which is supposedly the "God of Printers."

I'm really starting to lose it with this crap. It's not [solved] at this point. I guarantee you one thing. This is the last Original Prusa anything that I buy. It'll be cheap Chinese crap or bust. At least I would be able to print...something... even if it is just a waving cat!

RE: MK3S part melted

Is there any preventative measures I can take to avoid this? Would putting a thermal tape around it help avoid such issue?

RE: MK3S part melted

A lot of the melt issue is probably due to radiative heating. You may do better with a silicon sock installed. That would reduce the IR emission rate, improve hotend thermal efficiency, and be easier to clean. Get the pro version, but cut out enough so more of the nozzle tip is exposed. The regular version gathers too much plastic at the heater cartridge mounting screw head.

I would recommend using a silicone sock even if your printer isn't Droopy McDroopButt. If you are printing hotter materials than PETG, plan on making your own socks using high temp silicone. The E3D socks rapidly harden and become crumbly at high temps.

Tip: use a piece of beading wire as a garter belt around sock to keep it from drooping into prints.

RE: MK3S part melted

Yeah I'm huge a sock fan, but I keep havin em Droopy McDroopButt right off the block. LOL...
I've heard use a metal twistytie to hold it on, and while that works, I kinda wish there was a better solution to hold it on.

Edit: Beading wire! That is a great/easier idea! Thank you for that.

RE: MK3S part melted

 I'm worried to print on my MK3S to avoid such a mess..... 

What if  I apply normal silicone around that area, would it help?

RE: MK3S part melted

I don't have a pic,  but I think what he's saying is use it like a belt (pants/trousers), across the top of the sock, once it's installed.

However... be careful to not short out the heater cartridge/thermistor wires. I'd recommend having the printer fully powered down if you choose to do that.

RE: MK3S part melted

the e3d silicon socks have tiny molded ears that catch the top of the heater block , as they get older they tend to get looser, so the fix is to add a small wire horizontally around the sock/heatblock to retain the sock

RE: MK3S part melted

I think I posted this to another thread, but I've been running with a sock from day one and there was some pretty severe meltage on my R4 extruder. Not just the common fins, but also the extruder main carriage and the rear part of the extruder body, in some quite beefy areas. No structural issues but it was pretty globby and had flowed a bit. 

I'm actually running a custom molded sock that fits better than the official E3d and doesn't droop. 

RE: MK3S part melted

Are we talking about silicon socks that droop or actual MK3S part that is melting? I'm getting confused now...

RE: MK3S part melted

Both. The official E3d socks don't stay on very well, but there is also melting of the extruder plastic. Socks can help (which prompted a discussion on how to keep them on properly) but I've observed the contrary in my own experience.

RE: MK3S part melted

Ugh! That's a lot of melting - even with the help of a silicone sock.

Definitive solution seems to be a Prusa R4 extruder re-design or a completely different extruder.

RE: MK3S part melted

Indeed. I even had melting on the ABS fan (very minor, but there). Nothing as bad on the R3.

I noticed because I was building a skelestruder and was recovering parts from the old pieces.

RE: MK3S part melted

I was having High Temp PETG melt into a "raindrop".... after changing parts to CF Nylon, I've had no issues FWIW

RE: MK3S part melted

A beautiful filament. E3D had it on sale last week, unfortunately only in white

RE: MK3S part melted

I had this same problem about a week ago (posted in another topic).  My PINDA probe actually broke off!  There was evidence that heat stress caused the plastic to weaken and break over time.  I have printed mostly PLA since buying my Mk3S kit in early March but have more recently printed with PETG, ABS once some time ago and have heated up the hotend a number of times to remove jams and clogs.  I currently have my PINDA held in place with Gorilla glue temporarily until I get around to disassembling the extruder and replacing the broken part.  The printer works OK otherwise.  I think this part should either be designed different or made with a more heat resistant material.

RE: MK3S part melted

Having this issue also - having trouble with PLA prints not staying on the bed and noticed the pinda was tilting slightly to the right. Seems that the holder is bowing slightly. I print a lot of HIPS, NGEN, XT and Polymaker PC but do use an e3d sock on copper block. Find that the only fix for now is to reseat the sensor as best it will go and recalibrate. I'm reprinting the extruder in Polymaker PC Max.....