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One week in with Mk3  

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Greg
 Greg
(@greg-8)
Eminent Member
One week in with Mk3

Well, it has been a week since the long anticipated MK3 arrived as a kit and the build was not as arduous as feared. he manual was great and things went smoothly with few issues.
Trying to dial in the printer however has been a challenge.
The initial tests were passed with flying colors - no issues, so I tried the live z calibration
it went through that once, then on the second try would not go past station 8 - complaining of a sensor not being triggered - possible debris
Possible debris? I hadn't even loaded filament yet !
So a hard reset was required
Upon reset, the self test failed - apparently the thermistor in the print head was not talking to the controller
Weird - because it was just fine the first time through.
Another hard reset and the self test passed
The cal xyz worked up until the 'improving calibration' procedure which failed on the left rear position with the head diving into the heat bed
another hard reset - checked the probe height as per the manual - and it was fine
Cal x axis ended with the head beating itself to death against the tight hand y axis supports
another hard reset
all tests passed - hooray
Calibration passed - hooray
Live z procedure entered ran twice and ended with the head trying to dent the steel build plate
another hard reset
updated firmware on advice of chat representative - these folks on the chat are excellent !
Self test failed on the thermistor again
another hard reset
self test passed - cal xyz passed
live z ran multiple times until the required filament deposit had the flattening as shown in the book
Things are looking up !
Tried to print tree frog from the supplied SD Card - at 29% done the head started shedding one inch pieces of filament all over the build plate
the print became dislodged from its precarious hold on the steel plate

So the verdict is - many unexplained failures in self test, probe response and filament handling
and nothing sticks well enough to the build plate to actually complete a print.
The filament load path through the head is off, in order to load filament I have to remove the idler, grab the incoming filament with a pair of pliers and feed it into the PTFE tube leading to the print head - and yes - I've done the alignment procedure many, many times. There appears to be a slight mismatch between the position of the e Motor mounting and the mouth of the PTFE tube. The PTFE tube should be drilled out over size - or chamfered at the mouth to account for production tolerances. Alternatively the filament could be run through a pencil sharpened to make a point at the end so it has a chance of catching the mouth of the tube. Because every time I have to remove the two idler screws to open the space to load the filament, then I have to monkey around with getting the right tension on them again.

Not sure what to try next, I could I suppose put a raft or brim on the pritnts, but since I got this machine to print up the parts for the 3DLab planes - that are supposed to be printer ready - and which do not have rafts or brims - that will clear out the settings in those prints - making them useless.

Posted : 25/02/2018 4:46 pm
Jerry
(@jerry)
Estimable Member
Re: One week in with Mk3

regards inconsistent config results I see no mention of adjusting the PINDA height relative to nozzle? This was my break through in my journey. very happy now

Posted : 25/02/2018 5:39 pm
xhillb61
(@xhillb61)
Trusted Member
Re: One week in with Mk3

One week with the MK3.
no problems whatsoever. I took my time to assemble (12 hrs) and to reasure I was doing everything the right way.
Calibration, no Problems. Printer is running since then constantly. One time I had to rajust Z cause of filament change.
I would also guess you have to adjust pinda.
Good luck

Posted : 25/02/2018 6:02 pm
Kwaad2
(@kwaad2)
Honorable Member
Re: One week in with Mk3


regards inconsistent config results I see no mention of adjusting the PINDA height relative to nozzle? This was my break through in my journey. very happy now

Final setup task has you space Pinda probe with a zip tie. 😉

I just got mine running yesterday. I'm getting flawless prnts straight off the bed. time to build my own profiles now. (And I haven't even opened up the roll of Prusa Filament yet!

Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.

Posted : 26/02/2018 7:38 pm
Bigdogbro1
(@bigdogbro1)
Estimable Member
Re: One week in with Mk3

Purchase some 91% IPA and roll of paper towels to clean the heat bed every time you print. The extruder idler gear has flat plastic washers on either side to keep it centered and the drive gear must be well aligned to the idler gear filament groove path. I had been following this forum for months prior to getting my MK3 kit and my assembly went well but the printer needed S3D slicer tuning. Have never used the Prusa slicer.

The belts will never run perfectly in the pulleys center and stay there. Mine wander a bit but still have a glimpse of gear teeth or pulley on either side of the belt at worst. When I built my kit I focused on the rod alignments and bearing slide freedom and smoothness. I pre-greased all the bearings with a pea sized amount of Super Lube and worked it into the bearings with a round Q-Tip stick (no cotton end). I used Misumi bearings on the table plate only and the U-clamps were only tightened enough to hold the bearing into the bed X-Plate. The bearings could be slid end to end in the X-Plate slots with little force once the U-clamps were installed. I had some tiny bearings like were used on the idler pulleys so I placed one on either side of the idler bearings to use as a side play shim to better center the idler pulleys and keep them in position. Overall the kit build went well with these few extras and is now printing as expected. 😀

MK3 Kit, Designed, built 4x4 CNC Plasma Cutting Table, Motorcycles Bigdogbro's Adventures
http://www.youtube.com/channel/UC5djrxBeeOKB9_6rHnn6G8A

Posted : 27/02/2018 1:52 pm
Greg
 Greg
(@greg-8)
Eminent Member
Topic starter answered:
Re: One week in with Mk3

Well what a difference a week or two can make !
Finally got the machine stable enough to do the z calibration, using a magnifying glass to observe the filament as it was being laid down allowed me to dial in the correct height. Some 3Dlac spray cured the adhesion problems and everything is working well.

Posted : 13/03/2018 2:46 pm
Spartacus
(@spartacus)
Active Member
Re: One week in with Mk3

What to try next? Sell it to some fan boy and forget it like a bad dream.

Posted : 13/03/2018 5:11 pm
Jerry
(@jerry)
Estimable Member
Re: One week in with Mk3

Spartacus,

Will buy 400 bucks US where are you at? Call me a opportunistic Fan Boy is you like. I will buy your pain and eat your sin!

Posted : 15/03/2018 3:14 am
marco.b5
(@marco-b5)
Eminent Member
Re: One week in with Mk3

My experience has been a little hit or miss. After initial build I was immediately hit with a mintemp error with hot end reading 10/11 degrees. I switched the thermistor port with the hotbed port and got the same error on the hotbed on the switch so I believe that confirms a bad hotend thermistor. Support has one in the mail already but that meant a while without a brand new printer so I continued to experiment. Went ahead and ran calibration tests on XYZ and everything went fine.

Then as I was reading the internet (a large source of very bad ideas I know) I decided to test thermistor with a hairdryer. It detected the change in temp and actually allowed me to preheat. Then it allowed me to run the self test and everything passed. That doesn't seem healthy but I'm switching out the thermistor as soon as the new one arrives. At this point it's day three and I haven't even loaded filament. (Took me two days after work to complete build).

I go through the self test again. All passes. I start to print the Prusa logo and it gets to the far end of the logo and then proceeds to stay in one place and print a huge blob. WTF??? Run calibration....X axis error. I'm about to completely flip my lid when I notice that the stepper is spinning....but the gear isn't. Ok so that was my bad. I apparently forgot to tighten the lugs on the gear for the X stepper.

It took me about 2 hours to properly get the initial layer height right. (and in between it threw up another mintemp error...back to the hair dryer and "kickstarted" the thermistor again. The layer height was a combination of limited experience and thinking that I knew more than I did. I built my A8 and I've been printing with that for nearly a year and it just works. Nothing fancy, and loud as hell, but it works. I had four Prusa logos pull off the hotbed and two marvins fail before I got to what I think is a good first layer (with several Z calibration tests in between). I also made the mistake of running the wizard again, and reset the pinda. All in a days work with a new printer I guess.

It is not super well lit in my mancave/office/tiny little bit of space that I call my own. So I had to run a test and calibrate afterwards. I'm currently at 46% on my most recent marvin and it appears to be sticking to the bed just fine.

In comparing the experience of building and using an Anet A8 vs Prusa MK3 I can definitely say

Prusa machine quality of parts is waaaaaaay beyond what the Anet is. Looking over my Anet I count 12 different mods that I printed out/installed to get it to an acceptable level of safety and print quality. (but it is there by god). The parts don't feel nearly as solid and well constructed as the Prusa.

Instructions for building on the Prusa. Huh? you get an instruction book? It was a far more pleasant experience. Both online and in print the instructions were much more clear and easy to follow. Heck, in the version of the video for the Anet FROM THE MANUFACTURER they installed the build plate carriage upside down.

Noise level while printing........not even a close thing. I can hear the Prusa Whisper. The Anet screams. I originally had the printer in the living room. In truth, the level of noise that thing kicks off is one of the primary reasons I got my own little space. My wife hated it so bad and saw that I wasn't going to quit, ta-da, daddy gets some office space.

Price....well you know. I got the Anet to see if this was something I liked. I figured I could afford to waste $150.00 on something for a test run. A year later I claimed that I spent "around" 500 on the prusa MK3....that's true right?

I obviously haven't had the prusa long enough or done enough successful printing to have a real opinion. Thus far I've had a high percentage higher failed prints than successful ones (user error in most cases I suppose). Well.....now its 3 a.m. and I'm foolishly waiting for marvin to finish even though I need to be up at 6.

Posted : 15/03/2018 7:55 am
Olef
 Olef
(@olef)
Prominent Member
Re: One week in with Mk3

Well.....now its 3 a.m. and I'm foolishly waiting for marvin to finish even though I need to be up at 6.

Welcome to the brotherhood of Makers! 🙂

Posted : 15/03/2018 8:04 am
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