PRUSA edition heat break easily jam/clog with PLA  

RE: PRUSA edition heat break easily jam/clog with PLA

Posted by: karldavy149

i know he credits others but that doesnt stop the fanbois thinking he invented it ...

We get people who've purchased a "Prusa" clone coming in here asking for help. That's not fanbois. That's other firms using misleading advertising. How you think that's a Prusa failing is beyond me.

and agree what he does, does push the boundaries of 3d printing he takes other peoples ideas mixes and blends enhances them into his own product... t

While contributing vast amounts of intellectual property to the public domain. That is how open source works. It is not a vow of poverty. If you listen to his interviews, he frequently credits others and the community for their input. That is how open source is supposed to work, and why it does work as a development model. Everybody gains. 

That is also one of the reasons we have the "clicking extruder" they try to much to soon

The "clicking extruder" problem is hardly unique to Prusa printers. Go hang out in the support groups for other printers and you'll quickly see that it's a problem common to any air-cooled hotend design, particularly when used in hot environments. That is why E3D makes a water cooled solution. If you exceed the ambient operating temperatures for any FFF printer design, or if you exceed the volumetric flow rate for any hotend design, you will get skips and jams.

[...] the case i3 mega flawless printing with tmc 2130 drivers installed total cost 1/3 of prusa ender 3 flawless printing with mainboard and driver upgrade total cost 1/3 of prusa chiron flawless printing with driver updates total cost 1/2 prusa but double the print size u see where im going with this ! they are "clones" with less but u get more because u dont have the hassle of all these systems and hardware communicating with each other that create potential issues

Do you mean the AnyCubic I3 Mega? The one based on the Prusa I3 design? Support groups for any printer are going to be filled with problem reports. That's their purpose.

There's nothing wrong with the i3 Mega. I've looked at it for a 2nd printer. It's foolish to suggest that users of that printer don't experience problems though. If it suits your needs, go for it. Just don't expect it to be somehow immune to issues.

RE: PRUSA edition heat break easily jam/clog with PLA

I think I solved my issue : after a chat with the support they told me to put thermal paste on the heatbreak, never tried that because I thought there already was.

Turn out I was right there was already thermal paste, still I cleaned it, removed the old paste, applied a generous portion of the new thermal paste.

Also, all my ptfe tube provided by Prusa were al bit weared (because of multiple clog) so I made a new one.

After assembling everything, the nozzle is now closer to the heatblock and the heatbreak further away. I had to do a pid autotune and lower the print fan because of a thermal runaway (I think I need a silicon condom (don't remember the term 🙂 for the hotend.

But I was able to print almost all day yesterday without any problem.

RE: PRUSA edition heat break easily jam/clog with PLA

I think the assembled hotends already have thermal paste in them, but that can and does break down over time.  I've ordered a whole new hotend for mine as I found issues with it, besides a broken heater cartridge cable, the heater block was loose and it would have been next to impossible to remove the broken cable as mentioned above without breaking the thermistor wire etc., so one might as well start new instead of buying individual parts LOL.  I will also be using a silicone sock on the heater block too for temperature stabilization and to keep melted plastic off of it.  Using heat shrink wrap on the wires close to the heater block also works great too..protects the wires and melted filament doesn't stick to the rubber 🙂  I've also heard that using a small amount of oil, such as vegetable oil inside the hotend helps alleviate jams too but I've never tried this.  I guess only a very minute amount is needed by putting a tiny drop on a sponge or paper towel and running filament through the oiled part to lubricate the inside of the hotend.

RE: PRUSA edition heat break easily jam/clog with PLA

I've owned or used 3 i3mega printers from Anycubic and have had MANY problems with those.  I've also had issues with my Prusa MK3s printer too.  Some of those issues came because I was and am still learning about 3D printers and have made mistakes, other issues were with the printers themselves.  Some people use Anycubic printers and think they are great.  A friend and former co-worker of mine who is very seasoned with 3D printers and even builds his own, recommended the Anycubic to me because they are more affordable and are OK for a first printer.  My last Anycubic printer went in the garbage about a month ago LOL, now I continue to use and routinely repair my Prusa printer.  All 3D printers and users who use them have issues...it's part of the game.  You generally get what you pay for.  Prusa is good value for their price point.

RE: PRUSA edition heat break easily jam/clog with PLA

And I also must add to the pool of people affected with constant jams.

Trying to print 18cm statue divided in 3 parts (legs, torso, head+shoulders), using 0.25 nozzle and 0.1 layer height with azure Prusament PLA.

As I was able to successfully print legs which took around 10 hours, then torso requiring around 40+ hours is impossible to print due to constant jams ending with perforated layers (underextrusion) or complete jam resulting in printing nothing in air. Of course with extruder clicking.

Just moment ago must stop the print after 30 hours on 32mm height.

Examining the failed print I noticed that underextrusion happened two times already, around 4 and 9mm, but printer somehow managed to go through it and print correctly after the partial jams without problems until now when it stuck completely. It was forth attempt to print that part.

Reading various advises and topics on forums I make sure that nozzle is correctly installed, hotend cleaned, PTFE tube changed to new one, motor gear correctly placed and installed, idler gear tension set not too loose, not too tight, inspected volume flow in the Slic3r to not exceed V6 hotend capabilities, slow down the speed, tested various temperatures of the nozzle, to finally put a fan on the extruder motor which seems to get too hot after many hours of printing. But despite everything, and motor being only slightly warmer than ambient temperatures thanks to 24V fan borrowed from some laser printer, jams still happen.

I've read about people complaining on heat affecting their printers when there is full blown summer on north half of the world, but in my country, and room where printer work, temperature do not exceed 23-24 degrees from some time. So for now, only things I didn't tried yet is changing the thermal paste, play with de-retraction speeds and change the heatbreak many people mentioned here. And count that some of the proposed resolutions will work before the deadline.

RE: PRUSA edition heat break easily jam/clog with PLA

have you tried slicing with reduced retraction? say 0.4mm?

regards Joan

RE: PRUSA edition heat break easily jam/clog with PLA

Posted by: krystian.k

 So for now, only things I didn't tried yet is changing the thermal paste, play with de-retraction speeds and change the heatbreak many people mentioned here. And count that some of the proposed resolutions will work before the deadline.

Before changing the heatbreak I would recommend putting new thermal paste, this is quick and cheap.

Also make sure the nozzle is as close as possible to the heatblock (without touching it). After reassembling mine hotend was closer about a millimeter.Heatbreak threads are poping out just a little bit from the heatblock.

Also I found a post on Reddit where people fixed jams by replacing the noctua fan by a MF40100V1-G99-A

RE: PRUSA edition heat break easily jam/clog with PLA

Posted by: Robert

I think the assembled hotends already have thermal paste in them, but that can and does break down over time.  .

Yes the hotend already have thermal paste. My printer is 1 month old ...

RE: PRUSA edition heat break easily jam/clog with PLA

Hello, I have my printer since may. From the beginning I have the same problems with PLA. I tried a cooler for the extruder, different filaments, etc. PETG and ABS do not cause any problems, PLA and TPU more or less depending on the grade. I split my Hotend lately. It was noticeable that the PTFE tube losen again and again, so I set up a collet. But even this did not last the PTFE tube permanently. So I exchange this. But only after I exchanged the Heatbraek, the PLA filament could be printed, which caused problems from the beginning. I hope that stays that way.

I think it's a pity that Prusa apparently conceals this problem and does not fix it. Not everyone combs PETG or ABS printing ?! I hope they learn from it and fix it at least in future versions, even if current buyers will not be satisfied with it.

RE: PRUSA edition heat break easily jam/clog with PLA

Posted by: joan.t

have you tried slicing with reduced retraction? say 0.4mm?

Joan, have you tried reducing de-retraction speeds?

I'm finding I can get away with significantly reduce retraction distances (0.2-0.4mm) and z-hop with minimal stringing with retract at 50mm/s and de-retract at 25mm/s. Makes sense. If the retraction can pull a bit of molten stuff up enough to reduce pressure in the nozzle, then slamming that same molten stuff back in is likely to encounter the non-Newtonian characteristics of the hot filament.

RE: PRUSA edition heat break easily jam/clog with PLA

Is this what we would need to order to replace the problematic heat break: E3D v6 Heat Break - 1.75mm?

From MatterHackers it is under $15, free shipping. Seems like cheap insurance.

RE: PRUSA edition heat break easily jam/clog with PLA

I ordered this directly from E3D

V6 Heat Break

SKU: V6-175-BREAK

Input Diameter

1.75mm

https://e3d-online.com/v6-heat-break

RE: PRUSA edition heat break easily jam/clog with PLA

To sum up the heatbreak/ptfe tube recommendation, what should be used for both?  It appears it should be the normal E3D heatbreak, but what size of PTFE Tube?  4mm OD / 2mm ID?

RE: PRUSA edition heat break easily jam/clog with PLA

I used the original PTFE tubing that came with spare parts in my Prusa printer

but I added a collet clip because previously loosened the ptfe tube

RE: PRUSA edition heat break easily jam/clog with PLA

I have a MK2.5S that was the result of upgrading the MK2 through several iterations.  I could print most PLA filaments but when I tried to print Multi Media via MMU2S, I would get a MMU2 feed error.  In reality the problem was the tip formed during a previous unload would not pass the 2.0mm section of the heat break downstream of the PTFE liner.  In each case the tip was slightly greater than 2mm.  

Because of the origin of the printer (MK2) the heat break was a standard E3d and did not have the step to 2.2mm that is the case of the MK3.  However the PTFE tube which lined the cold part of the heat break measured slightly larger than 2.0mm.  I don't know the exact amount the ID exceeded 2mm but a 2mm drill bit was noticeably loose in the tube.  Prusa stipulates the use of PTFE tubes with 2mm ID and 4mm OD when manufacturing the liners.  I cannot say with certainly the the incident liner was not manufactured by me but I don't recall changing the tube.  Further causing me to believe the liner tube was OEM is the fact the exterior chamfer was more rounded than is the case for the ones that I make with a cutter.  In any event I replaced the heat break with a new one sourced from E3D and used a liner made from a PTFE tube with an ID of 1.9mm.

After the above changes I can print the 5 color MMU2 test without any failures.  This test has 120 tool changes. 

The resulting filament tips measure 1.9mm-1.95mm consistently so they easily pass through the 2mm section of the heat break.  This same fix should also work on the MK3 but I do not have a MK3 to perform a test.

RE: PRUSA edition heat break easily jam/clog with PLA

Just to add some information, I at first thought the jams where caused my a to hot extrude motor. But the hot motor only contributes to the actual problem decribed here (the 2.2mm to 2mm narrowing in the heatbreak).  I came to the same conclusion over a long span on time and reading a lot on internet.

Here is a thread I was active in describing the same problem (with lots of pictures) what we through at first was related to the extruder motor being to cause of PLA jams : https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-general-discussion-announcements-and-releases/extruder-motor-getting-too-hot/paged/4/#post-107234

I understand you can swap out the Prusa special heatbreak for the origenal E3D heatbreak (only 2mm bore and not 2.2 to 2mm). But what it adviced for people who have an MMU and hot summer day's and still want to 3D print? Anyone experienced with using the 2mm bore heatbreak with MMU? Or is this 2.2mm really needed? Are there other options beside installing an personal airco onto you 3D print enclosure? XD

RE: PRUSA edition heat break easily jam/clog with PLA

@wouter-h3

Hi Wouter

 I have 2 mk3's

One has a mmu the other doesnt

 Both work with the standard prusa heatbreak. 

I generally reduce pla retraction to 0.4mm and just print... tpu gets 0.0 retraction and 0.0 z lift,

Petg gets 0.4 retraction  and a light barrier of finger grease. To reduce adhesion. 

There are many interracting factors that either work together or work against each other. 

Ttpically people new to 3d printing have more issues than old hands. Often thw difference is patience and a litte finesse...

I also have a mk2 prusa with mmuV1. That gave me loads of issues to begin  with.  Then they brought out the new heatbreak andproblems reduced...

People often jump  on changing things too soon...  ymmv

Good luck. Joan

RE: PRUSA edition heat break easily jam/clog with PLA

@wouter-h3

Hi,

In my case just replacing the thermal paste solve my issue. Also, after re-assembling my nozzle was closer to the heatblock and consequently the heatblock further away from the heatbreak. To be on the safe side i also changed the noctua fan for a more powerfull one.

RE: PRUSA edition heat break easily jam/clog with PLA

Read https://e3d-online.dozuki.com/Wiki/V6_Troubleshooting   you should be able to touch the fins on the heatsink even after it's been running for a while and it should feel cold.  The MK3S design doesn't inspire me too much, nor does the fan - they simply dont cool it well enough to stop heat creep over extended periods of time. 

RE: PRUSA edition heat break easily jam/clog with PLA

Thanks for you reactions, I already did already all/most of what you advice ;).
Repaste with quility paste, moved the heatblock more towards the nozzle farther away from the coolblock, replaced the PTFE tube, checked retractions settings = still on default 0,8mm, Included an extra ceramic isolation whool and alu foil between heater and coolblock.

But I still get jams when printing around 31C ambient temperature although I think it first happend already around 28C so there is an slight improvement. It is winter here now, so I can print PLA just fine, but I have build my own temperature controlled enclosure where I can test different temperatures. And at around 31C PLA starts to jam and form the 2.2mm pucks again. So at warm summer day's I still can't print PLA.

@joantabb : Do you also have no problems at 31+ ambient temperatures printing PLA? It is only when ambient temperatures are high that I see all MK3's jam on PLA. If you have now problems then I really wanna know what you changed ;). I will try your 0,8 to 0,4mm retraction distance for PLA. You also mention other materials, but I have never had other materials like PETG jam on me even with +45C ambient temperatures and 2mm retractions in extrude temperatures between 250 to 290C. It only happens with PLA.