Questionable first benchy
First benchy on my Core One kit. Not super happy how it turned out. I’m new to 3d printing but I was pretty meticulous during the assembly. Followed tips for aligning the y rails and trapezoid nuts. I had a some trouble getting the belts within 3Hz while keeping the x rail square. Customer support walked me through an adjustment that helped a little, but still getting the constant rehoming calibration and banging before each print. Any tips what to check for first? 
RE: Questionable first benchy
This one looks like a 8min benchy, is that it?
RE: Questionable first benchy
It looks like the pre-sliced "rules" benchy from the USB stick to me? But the overhangs (under the roof and at the top of the chimney), as well as the long bridges (over the front window) don't hold together too well. I am wondering whether the right filament was used? The sliced model assumes Prusa's own PLA. If you were using some 3rd party PLA, maybe try again with one of the small samples Prusa included with the kit; each sample will easily have enough filament for a benchy.
The vertical waves on the hull are the much-discussed VFAs or belt ripple. All Core Ones seem to exhibit them to some extent, and CoreXY printers in general seem more prone to show them. We are hoping for some improvement via an upcoming firmware release which should enable smoother motor control, via "calibrated phase stepping".
RE: Questionable first benchy
Yes, it was the rules benchy from the usb. I did consider the filament as a possible issue. It’s Inland matte PLA. I’ll try it again with the sample roll. I can try slicing for a generic PLA too. I thought a larger spool of Prusament was included with the printer, otherwise I would have purchased some! I’ll place another order soon.
RE: Questionable first benchy
Yes, it was the rules benchy from the usb. I did consider the filament as a possible issue. It’s Inland matte PLA. I’ll try it again with the sample roll. I can try slicing for a generic PLA too. I thought a larger spool of Prusament was included with the printer, otherwise I would have purchased some! I’ll place another order soon.
It's probably worth doing both for a comparison -- printing the pre-sliced benchy with Prusament, and slicing the model for generic PLA. I found that my test prints with Prusa's PLA did indeed look more precise than the same models sliced for and printed with 3rd party generic PLA. Not sure whether it's really better filament or better-optimized parameters for the Prusament, or whether it was due to the age of my other rolls of PLA.
Yes, Prusa skimps on the filament when you order a kit. Only the pre-assembled printer includes a full 1 kg spool; the kit only has the two small samples. I ordered one roll of the Galaxy Black PLA with my kit to see whether it's worth the higher price, and my tentative answer is "yes". (I also like the black-and-sparkly look. 🙂)
RE: Questionable first benchy
So I’m not crazy! I must have seen the 1kg spool from the assembled option. When the kit became available I didn’t really have a chance to read the description. I just added to cart.
I would rate that print as good enough for the first month.
Every user builds their printer slightly differently and pre-built models are shaken up in transit so during the first few weeks of use the printer will run-in and settle its parts together; then you will have to go over the basic maintenance checks, lubricate and recalibrate. Even if you got everything dialled in perfectly today, it would all need re-doing.
Better to settle, temporarily, for a basic working printer and get some useful printing done, make your early mistakes, establish a routine and generally get used to the process. Then when you do your one month service you can take extra care knowing the new settings on your now stable printer are likely to last for several months.
Cheerio,
RE: Questionable first benchy
I ran a few more tests with interesting results. I already had a spool of Prusa PETG loaded, so I sliced a benchy for that using 0.25mm structural settings. The results are better than my first attempt.
Then I loaded the Inland matte PLA again and sliced for generic PLA with temp set to 210c, using the same 0.25mm structural settings. The results were similar to Prusa PETG.
Finally, I loaded the sample of Prusa PLA, and printed the rules benchy from the USB again. I'm discovering that the rules benchy is optimized for speed, so I realize these aren't apple to apples, but the results were worse than my first attempt using the same settings with Inland PLA. Everything was looking similar to my first attempt until it got to the top of the arches, then things started to get noticeably worse.
Prusa PETG (.25 structural) / Inland PLA (.25 structural) / Prusa PLA (rules)
After some initial prints I noticed the desk I assembled the printer on was shaking a lot, especially when making short fast movements. It was a solid oak desk with panel legs that seemed susceptible to rocking on carpet along the y axis. Before doing these latest tests I moved it to what I considered a more stable surface. A medium duty steel shelf on a concrete floor. The shelf surface "floats" in between two rails. Nothing really moves under normal conditions, but during the rules benchy there was still some excessive vibration. Could this be part of the problem? Is it more likely there's something loose inside the printer that's more noticeable under high speeds? Or is this still considered acceptable for these settings?
I also checked squareness and belt tension again before this latest set of prints. Everything was within spec (84Hz both sides). The print head banged into the front right corner for a few minutes before the first print, which has been relatively normal behavior. Before the second print this process lasted 15 minutes. There was a collision detected, multiple rehomings, and the nozzle cleaning failed the first attempt. Eventually the print started and everything ended just fine. I checked for squareness and bench tension again before the 3rd print and nothing had changed. This print started almost immediately, but the result was the worst.
RE: Questionable first benchy
The 8 min Benchy is the worst possible print to start with if you want to test for quality. It's all about speed so quality will be poor. I tend to always start with the small Prusa keychain that's on the USB just to test everything is working, then for a quality test I also use the Benchy but a I slice myself before printing.........
RE: Questionable first benchy
Got it! The first and last prints were the "rules" benchy, I believe it was 13 minutes. The ones I sliced myself that actually turned out well took closer to 35 minutes. I will just ignore the benchys on the usb stick for now and focus on other prints.
RE: Questionable first benchy
I ran a few more tests with interesting results. I already had a spool of Prusa PETG loaded, so I sliced a benchy for that using 0.25mm structural settings. The results are better than my first attempt.
Then I loaded the Inland matte PLA again and sliced for generic PLA with temp set to 210c, using the same 0.25mm structural settings. The results were similar to Prusa PETG.Finally, I loaded the sample of Prusa PLA, and printed the rules benchy from the USB again. I'm discovering that the rules benchy is optimized for speed, so I realize these aren't apple to apples, but the results were worse than my first attempt using the same settings with Inland PLA. Everything was looking similar to my first attempt until it got to the top of the arches, then things started to get noticeably worse.
Your two self-sliced benchies look nice and clean to me; that's what you can expect to get. I had mentioned the slight VFA waves before; par for the course, and hopefully they will be reduced by "calibrated phase stepping" in a new firmware soon. Another somewhat prominent printing artifact is the horizontal hull line -- that's a flaw which nearly all printers produce, so well-known that it has its own web page. 😉 So I think these prints look fine and suggest that your printer is in good shape.
However, if the pre-sliced benchy you re-printed is indeed the "rules" version, then that one is not ok. That gcode is trying to produce a benchy quickly which meets the standard rules (infill density, number of outer wall layers etc.), and has decent quality. Things should not look quite as wobbly -- the crooked chimney, the messy front right corner of the cabin, the gap in the front deck aren't right. Even the "bonkers" version of the benchy, which sacrifices quality for more speed, should look a bit better than that.
Vibrations of the printer could play a role. But I wonder whether the printer (chamber) might also have been running too hot? Were the top vents open?
While it has probably nothing to do with the print quality, minutes of head-banging to calibrate the head position also don't sound right. My Core One does the diagonal knocking 8 times if things go well (4 front contacts, 4 on the right), and occasionally 12 times. I had one single instance where it kept going and I switched the printer off after 30 seconds or so -- that was after I had just installed or uninstalled the accelerometer, I believe. I could not figure out what had upset the printer, and the issue has not recurred so far.
The usual advice is to check belt tension and squareness of the X gantry, which you have already done. I would also recommend double-checking that the X and Y movements feel reasonably smooth -- early on I had a blocked Y movement due to the filament sensor cable getting in the way. Maybe others have further suggestions?
RE: Questionable first benchy
The vent was open during all prints and the two off the USB were indeed Benchy Rules. The ambient temperature in my home is normally between 20-25c. Currently closer to 20c. If I recall, the chamber temps might have been 5 degree high at one point when I checked. It could have gone up higher toward the end, I was just watching the print more carefully at that point. I couldn't find enclosure temps in the logs. I can try printing another and keep a closer eye on that.
I have seen other people taking about head banging similar to mine. It's painful to watch.
RE: Questionable first benchy
My MK4s used to 'bang' the side while calibrating the X Axis around 16 times, and the same again for the Y-Axis. Always the exact same number of times every time it needed it. Once done it would print perfectly. This is irrespective of whether you calibrate with the accelerometer or not. Haven't got my Core One built yet to see if that does it, but I've never thought of it as being a problem TBH.
RE: Questionable first benchy
My MK4s used to 'bang' the side while calibrating the X Axis around 16 times, and the same again for the Y-Axis. Always the exact same number of times every time it needed it. Once done it would print perfectly. This is irrespective of whether you calibrate with the accelerometer or not. Haven't got my Core One built yet to see if that does it, but I've never thought of it as being a problem TBH.
How long did this process take? Back right corner on mine is a quick bump or two. The front right sometimes goes on for 5+ minutes. The record was about 15 minutes before the print started. Like yours, the prints all finished fine with the one exception I guess.
RE: Questionable first benchy
Ohhhh never anywhere near that long. Around a minute for the full process.....
My MK4s used to 'bang' the side while calibrating the X Axis around 16 times, and the same again for the Y-Axis. Always the exact same number of times every time it needed it. Once done it would print perfectly. This is irrespective of whether you calibrate with the accelerometer or not. Haven't got my Core One built yet to see if that does it, but I've never thought of it as being a problem TBH.
How long did this process take? Back right corner on mine is a quick bump or two. The front right sometimes goes on for 5+ minutes. The record was about 15 minutes before the print started. Like yours, the prints all finished fine with the one exception I guess.
RE: Questionable first benchy
Quick update. I tried reprinting a few days ago to keep a closer eye on the chamber temps. It didn't make it very far before I stopped the print. I was also getting frequent nozzle cleaning failed warnings even after cleaning the nozzle, so I double checked the specs on the Prusa Viva la Bronze PLA sample. I didn't realize this was a PLA blend and not a basic PLA. It was in the same package as the Jet Black sample, labeled "PLA". I changed out the filament for Jet Black Prusa PLA and the print turned out much better. Similar to my first attempt, with overall improvements.
I think the chamber temp was still a little high, which may have been responsible for some minor issues. The target temp was supposed to be 20c, and actual temp peaked at 26c. I may try printing it again at some point with the door open to see what happens.
I realigned the x rail and tensioned the belts again. I had been doing this before most prints due to the excessive head banging at the beginning of each print. Nothing seems to have changed and overall my prints are turning out ok, so I guess I'm just going to ignore it for now and see how it goes.
RE: Questionable first benchy
I double checked the specs on the Prusa Viva la Bronze PLA sample. I didn't realize this was a PLA blend and not a basic PLA. It was in the same package as the Jet Black sample, labeled "PLA".
Ouch -- I didn't realize that either. My apologies for pointing you in a misleading direction by suggesting the use of one of the "proven" Prusa filaments! 😣
Not Prusa's brightest idea to include this slightly exotic filament as one of the two samples, and not even label it properly. If the samples are meant for initial testing of the newly built printer, they better be compatible with the pre-sliced prints provided on the USB stick!
RE: Questionable first benchy
No worries! Those were my thoughts exactly. It did cross my mind to double check the specifics of the two filaments earlier, but there were labeled as PLA and I assumed they would be compatible with the pre-sliced prints. Thanks for your help!
RE: Questionable first benchy
In the past I tried several colors of PLA-Blend (Oh.my.gold, Royal Blue and pearl white ). Those were the only filaments from Prusa that I didn’t like at all ( Oh.my.gold being the worst offender ). Terrible interlayer adhesion, no matter the nozzle temperature. The finished parts were very brittle and also more prone to warp than any other PLA filament I ever printed. I’m not buying any more of this stuff, that’s for sure.
RE: Questionable first benchy
To use a PLA Blend you must choose the PLA Blend filament profile accordingly. It prints slower by adjusting the MVS to improve layer adhesion.