RE: MK4 PLA Stringing
I'm indeed on new firmware and slicer.
My results where with your numbers haha... Now I need to figure out the 0.4 settings.
RE:
I'm having the same issue on my second MK4 I received recently and I can tell you that in my case at least this is 100% temperature related.
As soon as I got the second MK4 assembled I pulled the flash drive from my first machine and started printing a gcode file for one of my production parts. Immediately I could see there was an issue as the part was printing much shinier than usual, I suspected temperature so I started lowering it. This part normally prints at 205C and once I got down to 185C it printed as expected. I then set both machines to the same hotend temp and measured with a thermometer, the new machine was showing 15-20C hotter so this confirmed the issue. I also ran the included gcode for the keychain and the new machine had much more stringing.
I then took it a step further and swapped hotends between machines and the issue followed the hotend so now the old machine was having the issue and the new one was working as expected. I figured I had done all the needed troubleshooting and could contact support for a replacement thermistor, boy was I wrong.
Dealing with Prusa support about this has been an absolute nightmare. I've had two different agents agree to send me a thermistor only to then be overruled by somebody else and then I get told that they need to research it further and a thermistor may not fix the issue. I've gotten a different story from everyone I've talked to. I did get an email from them a few days ago saying that they've done internal testing and they are also finding a variance between thermistors and that they are working on a fix. It sounds to me like they are getting thermistors from multiple suppliers and some of them are way off. I know that on my first printer the thermistor has blue wires and the new one has black wires. I also know putting in a known good hotend solves the issue for me but I can't get them to send me one.
I've owned many printers over the years and this is the only one I've ever had that I had to drop the temp 20C to make it work right, to me this is unacceptable at this price point. These are machines that are supposed to be usable in print farms and having to keep up with different profiles for each of them is not realistic. If they can't figure this out they at least need to add an option in the firmware to offset the hotend temp.
RE: MK4 PLA Stringing
Thanks for this info. It was what I also was kind of expecting. Linked this post also to prusa support.
Because of my second nozzle I was thinking to buy a second heatblock with everything for even more easy switching. Once it is arrived I will let you all know how it went.
RE: MK4 PLA Stringing
I was thinking the same thing, but no change. I bought a nozzle adapter and was using a Slice GammaMaster with that and had the stringing. I decided to get another heatblock with thermistor and heater, so I decided to get 2 thermistors and heaters with a 0.25 nozzle and 0.6 nozzle. I tried the new heater assembly with the original brass 0.4 nozzle and it worked same as before. I also changed the original heater block with the new thermistor and heater and still the same. I am currently trying the new firmware and PrusaSlicer with the ramping settings enabled. The only thing that has been helping before was temps in the 190 to 200 range.
Thanks for this info. It was what I also was kind of expecting. Linked this post also to prusa support.
Because of my second nozzle I was thinking to buy a second heatblock with everything for even more easy switching. Once it is arrived I will let you all know how it went.
RE: MK4 PLA Stringing
Then the question is, can we figure out what versions/brands of sensors we have..?
RE: MK4 PLA Stringing
These are the two I have. Blue wire one on the right is the good one. Black wire on left is the bad one.
RE: MK4 PLA Stringing
wburkett1965 what colors do you have?
RE: MK4 PLA Stringing
I originally had blue and that needed to either be much higher or cooler and now I have black and that seems stable at a lower range. I changed to both the black ones because I was wondering if the blue might be for the XL since it was very wrong. The XL uses a different version than the MK4. Trianglelab has heaters and thermistors on Aliexpress for the MK4 now. I am wondering how they perform?
wburkett1965 what colors do you have?
RE: MK4 PLA Stringing
I have a same problem as you guys. Stringing no matter what i do. My MK4 arrived with black wire thermistor and last week i ordered block, thermistor, heater. Thermistor came also black wired. Didnt try it yet but i will definetly try it today.
RE: MK4 PLA Stringing
I have ordered thermistor and heater from trianglelab. I will post results when they came in.
RE: MK4 PLA Stringing
hey guys.
I have the same problem with the black wired hotend thermistor.
measured the temperature at the heater block, see pics.
the real temperature seems to be 15 degrees higher than showed on the mk4.
(the measurement device is calibrated. we use it at work for surface temperatures of injection molding tools.)
(also gave the hotend a few moments to stabilize the temperature. directly after hitting the 200 degrees C on the mk4 display the measurement device even showed 220.)
hope prusa will solve this problem soon so that we can get new hotend assemblies.
RE: MK4 PLA Stringing
I checked the bed on the mk4 and it's between 47 on the left corner (the one near LCD) and in average 51-52 on central area. It looks like it's a little bit colder, however I understand it's not a solid method of measure things. It's also not directly related with stringing, as the printing body can be at a specific height, so bed temp is not relevant.
I just simply thinking about temperatures of the nozzle and other components - do we see correct, real values or maybe something is causing interference. I saw that printing at 195 degrees looks much better. Can someone check using professional camera - is it 195 for real? Maybe someone has FLIR thermal camera or similar professional equipement? Maybe in fact it's not 195 but 220 and setting printer to 220 is 260? Just blind guess.
This is exactly what I wrote in September - the real temperature is higher than in reality. I hope that prusa will fix that or they will replace this part.
RE: MK4 PLA Stringing
Well I have tried another set of heater, block and thermistor and no change in stringing. Also tried beta fw with slicer 2.7.0 and no change too.
RE: MK4 PLA Stringing
the real temperature seems to be 15 degrees higher than showed on the mk4.
Can you contact PS with this finding and see if they give you the same info as JHenley01.
New Beta Firmware didn‘t worked for me. but when i again set the print-temp to around 195 degree the stringing is almost gone. Speaks as well for your finding.
When i write back to support i will mention it as well.
RE: MK4 PLA Stringing
I'm also on the whispy strings train! I thought maybe I got a bad batch of Hatchbox PLA, but after going through this thread it sounds like it's definitely the MK4. I did the 3.5 to 4.0 upgrade kit.
I've tried a whole bunch of temperatures, from 220° down to 185° without input shaping, and so far everything is whispy. As I type this I'm trying 190° with Input Shaping (which is 30° cooler than the default for Generic PLA with IS).
It'd be great if Prusa found it's just a bad thermistor and sends us a new one...
RE: MK4 PLA Stringing
Same problem here.
In my case, as you can see from the photo, the stringing decreases as the temperature decreases and disappears completely at 180 degrees (45 degrees less than the default temperature with Prusament PLA).
So, at least in my case, it seems reasonable that the problem is the thermistor.
RE: MK4 PLA Stringing
Could be a simple firmware fix. They might have to adjust the way they readout the thermistor value in firmware and map with real calibrated temperature measurements. This off course if this temperature delta is true for all the thermistors they use.
RE: MK4 PLA Stringing
I installed 2.7.0-rc1 of Prusa Slicer and the 5.1.0 beta firmware, turned on Travel Lift with settings suggested by @OB1 here and my stringing is just about gone! I started at 190° with input shaping, looked great, so now I'm trying to ramp the temperature back up. I'm printing at 200° with Input Shaping now and this is the best my print has looked so far...
RE: MK4 PLA Stringing
Well this is looking like thermistor reading are wrong and new fw with slicer are compensanting for it by ramping settings. But this still doesnt solve the issue. I will take thermometer from work and do some measurements over the weekend. I will also try to check buddyboard and main board becouse this looks like the issue could be somewhere there according that multiple people have issues with multiple thermometers like me.
RE: MK4 PLA Stringing
hello soccermaster,
I get the same problem with my new MK4 received last week. Same print,same filament : on mk3S : no stringing at all, on mk4 : horible stringing.
Did you get a solution ? on my side lowering the temp is not a solution. I am using a PLA that requires 200-230°C, optimal temp on MK3S is 210°C thousands of print done with it on MK3S
On my side I checked the thermistsor (from 150 to 210, temperature is ok !)
Strange....