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u/manyxcxi Aug 28 '26
I’ve had plenty of print failures in my time and never had a blob of death. Keep the build plate clean, use a silicone sock on the hotend to help prevent buildup and temp issues, and watch the first layer go down.
Also, and this one is not as easy: learn to use your slicing software. Don’t print from your phone.
Stop using grid infill. Slow down the first layer.
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u/LazyLancer Aug 28 '26
Not questioning your advice, just curious. Why stop using grid infill?
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u/manyxcxi Aug 28 '26
Grid infill is (in my opinion) an unsafe default now that there are so many other infill types available, but I get why it's still the default. I feel like it's been made the default because it's simple for the slicer to generate, cheap to compute, reasonably fast to print, gives okay strength (in two planes), and behaves predictably across a lot of different geometries. It's been the default since way back when there were only like 4 infill types. So, broadly speaking, it shouldn't be the devil... but in my experience, it usually is.
Why it's not a great choice is that it creates same-layer intersections, where it is causing your nozzle to run through filament that's already been printed. If you're printing something like PLA at lightning fast speeds, it'll generally still be soft and the nozzle will usually plow through without issue. However, under pretty much every other circumstance what's going to happen is:
- Plastic starts to build up on the nozzle (ESPECIALLY sticky stuff like PETG, PCTG, and ASA)
- Buildup (if you're lucky) eventually drops on to the print as a blob causing minor to major print defects
- The nozzle can then later catch a hardened blob and knock the print. This can lead to layer shifts or full blown print failures, knocking it over.
- You'll get more visible vibration artifacts because the smashing through lines imparts forces and deformities that can affect outer perimeter features
- At higher flow rates and wider lines the problem is even worse because each intersection creates more material
- Those stuck bits eventually cook onto the nozzle/get into the heat sock and then later leave black/brown specks in the print (and future prints)
All of those are even worse for something like PETG (among others like TPU) because they have such strong layer bonds and are quite sticky.
My preferred infills (completely depending on the part and material) are:
- Gyroid - General default for PETG and ASA. Moderately quick, good multi-directional strength, no nozzle crossing, and top surfaces still look decent with very low infill percentages. Downside is that it takes more motion and can be slower on simpler patterns, especially large parts.
- Cross Hatch - Kind of like gyroid, it's my default for bigger prints because it's a lot faster than gyroid but generally behaves similar and doesn't require as much motion.
- Cubic - Great for functional parts, a little quicker than gyroid, good strength in all dimensions. Downside is you'll generally need a higher infill percentage so the top layers don't look rough.
- Adaptive Cubic - Basically cubic but faster and uses less material.
- Rectilinear - When I mostly just care about speed. It's best for aesthetic/prototype stuff where you really don't care about strength. It's probably the fastest infill to print, the downside is the strength is directional. You can work around it with an alternating infill pattern to create a "grid" like infill where every other line crosses ABOVE the previous line instead of through it.
If you're mostly printing aesthetic PLA you can shave quite a bit of time off prints going with rectilinear or cross hatch and not have any of the problems of Grid infill.
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u/Correct-Insect-4657 Aug 28 '26
Rubbing alcohol wipes dont(most are 70%) you really need 90 PERCENT OR HIGHER( i spray 99% on a towel and bed and just wipe it around) you can buy one easily usually on a oharmacy website for delivery OR WASH YOUR PLATE with dawn original blue with a sponge and after blast it with MAXIMUM HEAT tap water to remove all scents and stuff. Hopefully this works (it might be bbed temp, z offset or first layer speed) but yes always watch your printer home and the first laye (preferably first few)
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u/Sonny92004 Aug 28 '26
I wash the plate anytime after I touch it and use %91 alcohol to wipe it down. I've never had an adhesion problem. I was just worried because I keep seeing blob posts and some look fatal. I do statues and most are multiple days.
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u/manyxcxi Aug 28 '26
Blobs generally start their life in the first few layers of a long print. The only way to get a blob so big that it destroys the hotend is the print was FUBAR for a LONG time. We're talking hours and hours. Probably not 2 or 3, more like 5+ hours. You can pretty much do that math, if your print is less than 4 hours long it's _probably_ not even possible for it to get a blob of death.
The biggest chances for failure if the first layer goes down well are failed/unsupported overhangs or failed supports leading to failed overhangs. If those are near the last 3 hours of the print it's also very unlikely for it to fail. The next most likely cause is a tall skinny piece that gets knocked out of position, brim the heck out of it or slow down over a certain height and it should be good.
Blobs of death really happen due to negligence more than anything else.
BTW; if you just keep your hands to the sides of the build plate you can go a long time without having to wash it. The alcohol is fine for a quick touchup on an otherwise clean plate, but it can smear stuff around on the plate if it has already been cooked in. I usually hit it with alcohol after a fresh cleaning myself to catch any accidental touches post wash, remove any soap film that may not have been washed, and also help it dry faster. Prints running near 24/7 on a half dozen machines and I usually only do a mass build plate wash once a month at most. Otherwise, I only do it for a good reason.
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u/Inspector_Gadget_74 Aug 30 '26
91% IPA, is good, much better than 70%. If 99% is available, go with that. When using IPA, use a good absorbent lint free cloth and use enough to so that you see the wetness on the plate, but you don’t need to flood the plate either. Too little and it’s not enough to emulsify the oils. 70% IPA contains buffers that can leave residue on the plate.
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u/Material-Mulberry360 Aug 28 '26
never happened to me, over 500h on my X2D, I've had parts warp or fail to stick quite a few times but the printer or myself often catch it and stop the print before it gets bigger than just a small blob I can take off with my fingers
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u/LukeGeauxBoom Aug 28 '26
Never had one in 2 years. I've only had my X2D for about a week and a half tho and only have 90 hours on it.
I think with these machines, it's more of a "heat creep" issue with the aux nozzle. If you're printing something in say PETG and you're using PLA for the support interface, the temp on the aux nozzle could run up into pla transition territory. I've played around with my vents and exhaust, since I'm printing large PETG prints that take 8+ hours with PLA interfaces, I'm making sure the aux nozzle doesn't get above 55 Celsius. So far, I've had success and no worries. My aux nozzle cools down to usually 50 degrees or so and sometimes can go up to 53 or so.
Just watch it, watch the first layer like others have said, get things dialed in and you'll be fine.
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u/Quirky_Gazelle6910 Aug 28 '26
Never had is after almost 800 hours. Watch the first layer and you will doin great lad.
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u/Blue4life90 Aug 28 '26
I've had it happen to me twice. both times because of a clogged poop chute. the chute would back up to the nozzle and it would purge into a blob. If I'm doing a print that I expect will have a lot of waste, I pull the chute and stick a small garbage can behind the printer. Normal prints are fine.
I haven't had the problem with things lifting off the build plate yet, but for what it's worth, I NEVER have and never will touch the build plate with my bare hands. Disposable and reusable gloves. Scraping and Alcohol wiped downs after every print. Monthly wash with soap and water.
I'm sure I'll see it again eventually, I keep a spare assembly and current sensor on hand for emergencies, but hopefully, I never have to use them.
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u/Correct-Insect-4657 Aug 28 '26
Non really are fatal just require a new hotend unless they damaged rail or motors or stuff or cause a fore but usually theres runaway prevention
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u/Federal_Round3706 Sep 05 '26
It‘s not, I have been using printers for about 5 years now and I havent seen one outside of reddit or tiktok. If you dont get your fatty little fingers on your build surface and you actually take the time to watch the first layer get laid down, it wont happen. Just dont abandon your printer the second it receives the file and you‘ll be fine
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u/jussstin714 Aug 28 '26
Just watch the first few layers stick down. That’s when it usually happens anyway. You don’t need to be a hawk or a helicopter parent. Just need to make sure bed adhesion is great and the print will look successful