PLA
The preset temperature for Generic PLA is too hot. Old rule of thumb for PLA… the correct temp is the temp that just fuses, no hotter. As such 215c is too hot. I knocked off 15c and set it to 200c and it’s fine. If you go too hot it takes longer for it to leave the completely liquid state. We want to transition between solid and liquid and vice versa as quickly as possible with PLA since PLA behaves like ice vs other materials that behave like wax, I.e., they stay solid but soft.
Note!
The XL does not like older, brittle PLA! The long ptfe guide tube is a nasty trap for breaks! And… the fancy shmancy sensors cannot detect these breaks. Another rule of thumb… never stock up on PLA. UV light makes it brittle within just 12 hours and the filament breaks real easy. (it’s not moisture it’s UV). As such keeping open spools of PLA on the sides of the machine or out in any form of light will make it go brittle very quickly. Once brittle you may find yourself in a bit of a pita X 5 real quickly with this machine.
RE: PLA
I have been printing PLA at 205. I might try to drop another 5 after I finish my enclosure. So far no issues with the feed tubes and I have printed 8kgs of PLA so far.
RE: PLA
One spool I put on right away was a white pla with not much left on the spool. The end tip was deformed from, well being at the end. The tip clogged the guide tube to the run out sensor. Neither sensor caught it.
Next I had another spool which seemed fine, but after a few prints I got a filament break in the guide tube. Getting it out was tricky. Next it broke again in the extruder. Luckily I was able to feed it through and clear it. Again, neither sensor got it.
RE: PLA
I've been printing at 195-200 and it still feels like this is a tad too warm. Stringing is at a minimum with good filament like Prusament/Polymaker, but the vertical surface textures still look a little squishy/muddled. The more I've printed on this, especially after watching the latest Made With Layers video about the mk4, I suspect that surface texture issue has more to do with the printer firmware, and I really hope the next firmware change with input shaping helps there (both with and without input shaping, as for the most part I care more about quality than speed … which is the entire pitch of this printer vs something like the X1 Carbon).
RE: PLA
Input shaping is not a panacea. It will help, but it’s no cure all on any machine. I have it working on two of my non Prusa machines and yes it improves print quality at faster speeds, but it won’t fix all issues.
Also, retracting out of the melt zone when the tool is parked helps a lot.
Regardless, leaving pla spools on this machine will become problematic due to the long lengths of the guide tubes. The stuff goes brittle fast and it breaks in the tube.
RE: PLA
Yeah, I'm less interested in input shaping (though I installed it today and it seems pretty good so far) than on the dramatic improvement in regular prints that the mk4 showed between its first input shaping firmware and the final release. Looking forward to new anti-stringing features like z-ramping and Prusa looking into the temperature issues, too.
RE: PLA
… never stock up on PLA. UV light makes it brittle within just 12 hours and the filament breaks real easy. (it’s not moisture it’s UV). As such keeping open spools of PLA on the sides of the machine or out in any form of light will make it go brittle very quickly. Once brittle you may find yourself in a bit of a pita X 5 real quickly with this machine.
Some while ago, I spoke with a polymer scientist with familiarity of FDM filament materials. I asked him specifically about embrittlement. He said humidity-induced embrittlement is totally reversible in a filament dryer. And UV degradation from indoor lighting is negligible; it would take years, not hours. Direct sunlight, however, could do it in a few hours.
Whatever you find to do with your hands, do with all your might!
Agreed, PLA can pick up enough moisture to become brittle within the duration of a single print 'though it usually lasts longer. UV damage can be seen in a matter of weeks in summer - so painting anything that will be exposed is essential.
For strong parts, and PLA does make strong parts, stay at the hotter end of the printing range and slow the print down to ensure good interlayer adhesion. I don't see much point in input shaping for typical functional prints 'though it won't hurt.
Cheerio,
RE:
We’ve read all the reports on this for years now. We’ve also tested for ourselves and we live in a relatively arid climate. It’s not moisture alone, what we see is more effect from UV light. Baking the spool in a dehydrator for a full day won’t remove the brittleness once it goes brittle.
RE: PLA
Baking the spool in a dehydrator for a full day won’t remove the brittleness once it goes brittle.
Then you left it wet for months and as the moisture level and temperature varied it microcracked. No longer just brittle.
I have six year old filament that still prints - but it was dried, kept with dessicant and re-dried every time it was used.
Cheerio,
Cheerio,
RE: PLA
Let me guess Diem… that six year old… PLA? Wasn’t stored in light was it? Somehow I would doubt that you left it in a clear bag out in the light. We also have gotten feedback from chemical engineers since we’ve printed for them. We store PLA like everyone else in a sealed bag and with desiccant bags. If the bags are clear it goes brittle, if the bags are light proof the stuff lasts quite a bit longer.
We don’t do this as a hobby. We are a consulting and printing service for Engineering companies and artists in our area. We have a very large and diverse number of machines and we purchase our filament in larger quantities than most. And we’ve been doing it since before the folks at Bath UK started the open source community.
Instead of just being contrarian, I suggest you and others here do the tests that we have. Push it to the extreme. Put a coil in water for a day, leave another coil in sunlight for a day, leave a third coil in a completely dark room and then test them for yourself as we did.
BTW… none of this applies to any other material. Only PLA.
Cheerio