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Prusa Kit First Print Difficulties, Ready to give up 🙁  

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JT
 JT
(@jt)
New Member
Prusa Kit First Print Difficulties, Ready to give up 🙁

Hey all! 

First let me say that I think Jo has built a great machine and the engineering and work that has gone into its design and the continued support that I've seen and heard about is awesome from him and his company (as well as the Prusa community). This is largely in part why I'm posting for help/direction here. 

I've had my Prusa MKS3 kit since mid-February and have had a very mixed experience regarding it. I bought the kit, and probably like most, to both save money and to have the detailed experience of having a better idea on how it works and how all the parts fit together. Though it took me much longer to put it together than I expected (almost a week with working full time), I finally got it all together and felt a high level of accomplishment. I'm going to post here some of my frustrations below though and ask the community if this is common (eg a normal learning curve) or lack of mechanical experience and skill on my part.  

My first issue came up with the cover for the heating plate cable. This one was very minor but I had issues getting the cover to screw in and I eventually stripped the plastic holes the nuts were set in. So I tried supergluing it a few times and failed after twice waiting 24 hours for the glue to set. I settled on both screws being in there, but really only one partially holding it. Hoping I can reprint it and replace it once I got the printing working in tip-top shape. 

My first real issue came up when I was having problems getting a decent result by printing the first layer test and Prusa logo. After a fair amount of googling and reading the forums, it appeared that I had not enough tension along the x-axis (my memory is a little fuzzy on some of this so bear with me). Solution to my problem or not, I noticed the belt was too easily pressed together and then tightened it on the left end per direction that I had found. I was successful in tightening it until I tightened it too far and cracked the x end motor piece. This one devastated me the most as I felt It was my own ignorance and to some degree, not having the directions be clear enough what is too much. Either way, I'll caulk this one up to being on me, not the machine. Until the most recent issue far below, this one I took the hardest.  

I was able to super glue this part together and surprisingly, it held quite well, and appears to have held up since. Though my intention is to replace it once I'm able to  (and if I'm able to), complete a more complicated print. After many many MANY repeats at the first layer print, I moved on to the getting the logo printing correctly. After some adjustments, messing with the zlive adjust, I excitedly got it dialed in. I moved on to a larger print which went okay However, when I went to change out filament for the next print a few days later, I had some filament stuck somewhere in the extruder. I tried multiple routes to get the filament freed but had to resort to popping the extruder assembly out and examining it closer. I used a heat gun to loosen it up, pocked around with the provided needle, etc and appeared to have successfully cleared the blockage. However when I went to screw back on brass(?) extruder tip, I must have accidentally cross threaded it and then used too much force because I snapped the threaded part off in the heating block and couldn't get it out. So I had to order a whole new extruder assembly which I received a weekend or so ago after 5 days or so. I installed the new extruder assembly fairly easily but it was another setback, which was almost certainly self-inflicted.  

I then went through the whole setup again and getting the offsets on the bed and z set up. Again went through multiple first layer print calibration tests, and closed to a dozen Prusa logo tests but I got it printing the logo perfectly after what felt like too long. I excitedly moved on to printing something larger but not overly complicated, a Blantons stand from the Prusa site. I failed at this 4 or so times, tweaking the bed temperature, first too low, then too high, utilizing the glue stick, reading up more on the problem and how to fix. After multiple times getting to around 1.75 on the z and failing, I managed to finally get it even further into the print. The little logo was peeling up which concerned me, and still not sure how to fix (except by printing separately) but I let it print over the evening last night. I set it to 70% speed as when I print at too much a higher speed on anything, it almost always fails. I woke up this morning for it still trucking along and only 2.5 hours left to go. I went to work, checking on the print remotely every 20 minutes to make sure there weren't any hiccups. With an hour or less to go, the print came loose on the bed again (this was an issue I kept having by having the bed too low a temp or too high) and I had to kill the power to the print to prevent it from globing up and/or causing a fail or damaging the printer. This one just took pretty much the rest of the wind out my sails though. 

Now I didn't write down everything, nor do I remember every hardship or failure that I had but I hope I somewhat conveyed my frustrations and feelings with the issues I have had. My question to the community is, are some or most of the difficulties I've been having at all normal? Or just my lack of skill in dealing with a complicated mechanical machine such as this? I'm just so discouraged, having never really had a 100% satisfactory completed (more complicated) print that I'm about a week away from giving up entirely. I've spent so much time, and additional money on my mistakes, that I'm ready to try and return (though that I assume is unlikely) or to just try and resell the machine at a loss and buy something more turnkey. I hate to say it because I really had high hopes and the few successful rays of sunshine I've had were awesome, I just don't know what else to do. 

I'm frustrated with the overestimation of my skill to do this (and that I just didn't buy the printer preconstructed) and with my mistakes, frustrated with what I can consider bad luck, and nearly out of positivity that I can get this working. I feel like it's more on me than the design of the machine due to the mostly positive comments I've seen across the board. Because since it  likely isn't the machine, then it's all my incompetence and I either need to be talked off the ledge and told to be patient, or this printer just isn't for me. I appreciate anyone who read through this and responds. I know I hate reading walls of text so I really do appreciate it. I just want to get to printing and enjoy it the way everyone else does. 

Posted : 12/03/2020 2:24 pm
stoofer
(@stoofer)
Estimable Member
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

There are going to be a lot of opinions coming your way, here's mine 🙂

1.75 on Live Z adjust is too much.  Move the PINDA a whole thread closer to the bed. Try to keep it under 1.0 Live Z.

What material(s) are you printing?

For bed adhesion:

Layer 1 is crucial. Calibrating layer 1 is an art. There are lots of threads here, so I'm not going to dig into it other than to say I think you've probably got it wrong. Slowing down layer 1 for success is not uncommon, then go back to full speed for the rest of the print.

Likewise a thicker layer 1 is also quite common.  This allows you to be a bit less accurate in your Live Z setting. Try increasing this.

Cleaning the bed properly is essential.  Again there are lots of threads here about it. New beds are not ready to use, they need cleaning.

Bed temp should be just below the glass transition temperature of your material.  Exceeding this will make the lower layers of your prints terrible, as the print will remain soft.

Are you now getting other errors besides parts not sticking to the bed?

Posted : 12/03/2020 2:52 pm
JT
 JT
(@jt)
New Member
Topic starter answered:
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

@stuart-b4

Thank you for your response Stuart. I will look closer into those other threads and look into items you mentioned. The other problem I ran into was I thought the PINDA was too low as with larger prints, it was catching on the print but now I know that may have been due to bad first layer and bad adhesion instead of the probe being too low. 

Other than that, I have had multiple times on the Prusa label print where the extruder would start creating a mound of filament, usually near the bottom long edge. Raising the bed temp and using the glue stick cleared those issues up, but then on the lager print, (after reading the forums, I discovered I had the bed temp too high) which eventually caused adhesion issues by being too hot. When I had lowered it down from 70 to 67, that is where I got the farthest until the failure with an hour to go. When I was closer to 60 for the first layer calibration print, it seemed fine. But for the Prusa logo at 60, then it wasnt sticking again. Tt seemed to need to be up to 65 to work better there. I had read somewhere on the forums that 70 in some cases worked and for a while that did for the logo, but then again, starting failing on the larger print which was why I dialed it back. I also thought the catching could have been due to a skew so I had played with the bed leveling a bunch and that likely has got me all turned around. I need to start back from square one, be patient, and by process of elimination, reduce where the trouble areas are. Being patient is the area I'm clearly struggling with at the moment. I thought that I might have a layer shift going on but I can't tell from the crummy video feed so I'll have to check when I get home.

I ran the whole thing at 70% speed, in fact most prints I have been. I've been only printing in Hatcbox PLA so far.

I had followed one direction set on here to wash the sheet with dial soap and then bake it at 80C on the board for 30 minutes. But I discovered that late and had only been using 90% iso before that, which was also before I started using the glue stick.

So I will try to relower the PINDA sensor. I thought when I recently actually raised it up, that I was able to reduce the zlive offset some but still not below 1.0, or even close. It sounds like I'll need to fiddle with the bed temp a little more as well. 

Thanks again for the response! It certainly made me feel a little better about where I'm going wrong, rather than what was starting to feel like blindly guessing at this point. 

Posted : 12/03/2020 4:55 pm
stoofer
(@stoofer)
Estimable Member
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

It's difficult when you run into multiple issues to troubleshoot.  If your print is warping and lifting off the bed, your nozzle or PINDA may be crashing into the warped parts, so your failure of knocking the print off the plate could actually all be down to layer 1 adhesion.

When I calibrate Z with the prusa calibration, I will gently "rub" the single strand sections.  If it moves from the bed easily, I lower Z until it can be resistant to a mild rubbing - this seems to get the right amount of squish for me.  Everyone ends up with their own method/madness for this, which is why I described it as an art 🙂

Note your sheet may still need more cleaning. I recently bought a new sheet and was surprised at how many prints and cleans it needed from brand new to stick properly.  It does seem to get better over time.

Posted : 12/03/2020 5:08 pm
JT
 JT
(@jt)
New Member
Topic starter answered:
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

Thanks again Stuart. I also remembered earlier on having issues with the PIDA, adjusting it a bunch because I kept failing the XYZ calibration where it checks for 4 points by hovering over and checking with the probe each location first without and then with the steel sheet. I failed that many times my first go around before I broke the extruder. That's why when I finally got it to pass, it felt like winning the lottery, and I left it where it was and then just played with the livez. I was afraid of it not working anymore as that did take me quite some time to get it 'right'. 

From the post or two I read, I didn't realize how many cleanings I might need so that tip is good to know. I'll take a deep breath and get back at it in a few hours and restart the calibration from zero and see how it goes 🙂 

Posted : 12/03/2020 7:42 pm
JT
 JT
(@jt)
New Member
Topic starter answered:
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

So as far as I can tell these are what my problems are...

1. Moving the probe down so far, APPEARS, to have no effect on the height at which is starts running the first layer calibration. I'll do some digging in the forums before I ask any questions here. I'll post a picture if I keep getting hung up on it. I've lowered it a couple threads and I swear it is still too high. The first line at the bottom of the test layer starts of swiggly, then straightens out, and as it goes back and forth the turns are very curve and not square. The end, close back and forth, doesnt stick at all bc the tip is too high and mostly just globs together.

2. The curling issue. The latest print I had where it had almost finished a larger print, showed signs of curling even though it stuck for a quite a while before it finally came off (except for a smaller piece). I'll post a pic of this as well if I keep getting hung up on it. I also stupidly realized that I might be using the wrong sheet for PLA, so that made me feel a bit stupid. But I'll do more research on this too before I ask any questions.

3. Layer shifting. Half of the latest upper print definitely looked shifted a bit. I can send a pic of this as well. I'll worry more about that after I fix the first two.

Posted : 13/03/2020 11:27 am
rmm200
(@rmm200)
Noble Member
RE: Prusa Kit First Print Difficulties, Ready to give up 🙁

Please follow the manual for setting PINDA probe position.

Lower the nozzle to a piece of paper on the build sheet. Loosen the PINDA probe and lower it to a zip tie on the paper.

Tighten the probe and never worry about it again. Setting Z is something totally different.

Posted : 13/03/2020 4:24 pm
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