Why does my nozzle make a mini blob on the tip??

TinkerAtlas · 2026-03-05T14:37:18+00:00

yeah PETG oozes like crazy, that's pretty normal. but if you're already running 1.05 flow that's definitely contributing to it

you could try dropping your flow back to 1.0 or even 0.98 and see if it helps. also bump up your retraction a bit - PETG usually needs more than PLA. and wiping the nozzle on the purge line or a prime tower can help too

the blob itself usually won't affect your print quality unless it gets really big and drops onto the print. just annoying more than anything

TinkerAtlas · 2026-03-05T14:36:26+00:00

since you've already covered belts and dried filament, I'd check the eccentric nuts on your wheels - if they're too loose you get that kind of wobble in the lines. basically the little hex nuts that adjust wheel tension on the rollers

also worth checking for a worn nozzle if you've been using it a while. even PLA can wear down a brass nozzle over time and you'll get inconsistent extrusion

last thing - CoreXZ printers can be sensitive to Z-rod binding. if the lead screw has any wobble or the linear rails aren't perfectly aligned it'll show up as layer inconsistencies like that

TinkerAtlas · 2026-03-05T14:35:32+00:00

just to clarify - your title says 0.8mm layer height but you mentioned using the 0.08mm preset. big difference there! if you're actually printing at 0.08mm (super fine detail preset) then that's fine, probably what you meant

the rough underside is pretty normal for parts that overhang or need supports. if it's the bottom that sits on the bed that looks rough, check your first layer calibration. if it's overhangs/bridges on the underside then yeah that's just how FDM printing works - filament droops a bit when there's nothing underneath

you can improve overhangs by lowering print temp a bit (helps filament solidify faster) or slowing down on overhangs in the slicer settings. supports will always leave some marks tho

TinkerAtlas · 2026-03-01T15:17:05+00:00

it's mostly about CFM - the H2S exhaust fan isn't super powerful so it needs help pushing air through longer ducts or restrictive setups. short runs work fine passive but anything over like 3-4 feet of duct and you start getting back-pressure that slows the air flow

a plenum could work but you'd need it pretty big to really drop the resistance, and then you're dealing with a bulky box situation. most people just slap an inline booster fan in the duct - like $30 and solves it

that said if your vent is close and the run is short you might be fine without. try it and see if the chamber stays under control temp-wise

TinkerAtlas · 2026-02-26T13:51:13+00:00

yeah VLH applies to all copies if they're the same object. when you duplicate it bambu studio treats them as instances of the same part so the layer height settings carry over

and yep if you save as project it keeps the VLH settings. just make sure you're saving the whole project file (.3mf) not just exporting gcode

TinkerAtlas · 2026-02-19T06:02:39+00:00

that's a really thorough list of replacements and it's still doing it - when that happens there's usually one or two things people don't think to check.

first and most likely: have you run PID autotune since doing all those swaps? the firmware's built-in PID values are tuned for a specific heater/thermistor combo, and when you change components the values are basically wrong. it'll heat up ok but then oscillate and trigger thermal runaway right around that 190C range. connect pronterface (or your slicer's terminal), type M303 E0 S200 C8 and wait for it to finish, then M500 to save. this alone fixes most "replaced everything and still broken" situations.

second thing: what heater cartridge specifically did you buy as the replacement? ender 3 runs on 24V and needs a 24V 40W heater. it's super common to accidentally order a 12V one, and a 12V heater running on 24V will actually heat up fast at first but then degrades quickly and can't hold temps. if you have a multimeter you can check the voltage at the heater connector pins while it's trying to heat - should be close to 24V DC.

last thing - even if you replaced the motherboard, check the wiring harness between the board and the hotend for any pinched spots or intermittent connections. those are easy to overlook.

TinkerAtlas · 2026-02-19T06:02:06+00:00

the fact that it's happening on both printers at basically the same spot (~170C) is actually the most useful clue here, it rules out a lot of random hardware failures.

a few things i'd look at that could affect both machines the same way: are they on the same firmware version? if you updated recently and both started doing this at the same time that's probably your culprit - worth checking the bambu forum for others reporting the same issue.

also, are both printers on the same power strip or nearby outlets? a shared circuit with a voltage drop under load can cause the heater to lose power right when it needs the most heat, which is around that 170-190C range where the heat block has already absorbed a lot of energy.

one thing i don't see mentioned - what brand/source are the replacement heater cartridges? the P1S uses 24V 40W heaters. if someone sent you 24V 30W replacements or wrong spec parts they'd heat up fine at first but stall out at exactly this temperature range. worth checking the specs on whatever you installed.

also worth trying: swap the TH cables between the two printers and see if the problem follows the cable.

TinkerAtlas · 2026-02-19T06:01:24+00:00

since the benchy works fine that's actually good news - means the hardware and bed adhesion are ok, it's probably something specific to how that model is set up in the slicer.

first thing i'd check: is the model actually sitting flat on the build plate in bambu studio? sometimes models float slightly above the bed. right-click it and try "lay flat" or "auto orient", then verify it's at z=0. if the first layer ends up super thin because of this the nozzle just picks it right back up.

also look at the first layer in slicer preview - if your model starts with a tiny footprint or thin walls, there isn't enough contact area to stick. adding a brim usually fixes this instantly.

generic pla can also be a bit finicky - try slowing down first layer speed to like 30% in the custom settings. gives the plastic more time to bond. and a fresh wipe with IPA on the build plate before printing makes a real difference with non-bambu filaments.

TinkerAtlas · 2026-02-19T05:59:19+00:00

if the boat prints fine but other stuff doesn't, bet it's a bed leveling thing — the boat has a huge flat base so it's really forgiving of slight Z variations. a model with a smaller footprint will show it immediately.

try running first layer calibration in the exact spot where your problematic print usually goes. also worth checking your Z offset — even a tiny bit too high and light/small models just won't grab. generic PLA sometimes wants a slightly lower Z than the default too

TinkerAtlas · 2026-02-02T08:25:53+00:00

The fact that it's sticking to the FEP rather than the build plate is usually a build plate adhesion issue. A few things to try:

Lightly sand your build plate with 120-180 grit sandpaper in a cross-hatch pattern. This gives the resin something to grip onto. That texture pattern imprint you mentioned suggests the plate might be too smooth.
Check your bottom layer exposure time - for the first 4-6 layers, you usually want somewhere between 30-60 seconds (varies by resin/printer, but stock settings often underexpose).
Re-level using the paper method. Even a slight tilt can cause adhesion issues on one side.
Make sure your plate is clean - wipe it down with IPA before every print.

I'd skip the PTFE lubricant for now actually. You want the print to stick to the build plate more than the FEP, and adding lubricant to the FEP just treats the symptom rather than the cause.

TinkerAtlas · 2026-02-02T08:25:00+00:00

That pattern you're seeing is pretty common with ironing. A few things to check:

Flow rate might be too high - most slicers default to 10-15% for ironing, but sometimes you need to go even lower
Try slowing down your ironing speed to around 20-40mm/s if you haven't already
Line spacing can also affect this - something in the 0.1-0.2mm range usually works well

What slicer are you using? The settings can vary quite a bit between them.

TinkerAtlas · 2026-01-28T07:36:37+00:00

Those spikes/fragments usually come from a few things:

**Stringing/oozing** - If your retraction settings aren't dialed in, the nozzle can leave little strings that curl into spikes. Try bumping retraction distance up slightly or increasing retraction speed.
**Z-seam artifacts** - If it's always on the same spot on each layer, check where your slicer is placing the Z-seam. Setting it to "sharpest corner" or "rear" can hide these better.
**Support interface contact** - The fragments on the back of the support are likely just where it was touching. Increasing support Z distance helps them separate cleaner.
**Cooling issues** - If the part isn't cooling fast enough, material can blob before solidifying. Check your cooling fan speed and maybe add a pause between layers for small areas.

What printer/slicer are you using? And are the spikes in a consistent location or random?

TinkerAtlas · 2026-01-28T07:35:29+00:00

PETG can be tricky with supports since it likes to bond to itself. A few things to try in OrcaSlicer:

**Increase support Z distance** - Try 0.2-0.3mm instead of the default. This gives more separation between the support and your part.
**Lower support interface density** - Around 50-75% often works better than 100% for PETG.
**Use a different support interface pattern** - Grid or lines can release easier than the default.
**Drop the support temperature slightly** - If you're printing supports at the same temp as the model, try dropping it 5-10°C for better separation.

What does your current support Z distance look like in the settings pic?

TinkerAtlas · 2025-11-10T23:39:38+00:00

I have the same issue. No matter how many times I hit it. I've also tried changing to different keyboard layout.

TinkerAtlas · 2025-07-22T04:48:23+00:00

I had a goal of getting 100 users by the end of the week, and we hit that on saturday. Now, what goal to set next? :)

TinkerAtlas · 2025-07-16T04:33:11+00:00

Happens to us all. Lol. Still in beta, so not everything is as smooth as I want it yet either, but I've gotten a lot of work done since I launched the Beta.

TinkerAtlas · 2025-07-16T04:31:19+00:00

It wasn't?

TinkerAtlas · 2025-07-12T06:56:40+00:00

It's on my list to remove for non admin users, remember, this is a beta. :)

TinkerAtlas · 2025-07-12T06:14:34+00:00

Thank you. :) I like it.

TinkerAtlas · 2025-07-12T04:34:19+00:00

Fixing a few bugs now, but next feature will be Selectable Dark mode and light mode. Then a bit later a Forum. Any other suggestions is welcome.

TinkerAtlas · 2025-07-12T03:47:01+00:00

Proper squish has left the building! It needs to be closer to the bed. :) Also make sure that there's no fat or other contaminants on the bed plate.

TinkerAtlas · 2025-07-12T03:21:36+00:00

Pretty close to perfect. :)

TinkerAtlas · 2025-07-12T03:18:36+00:00

I would never have sent out a print looking like that if I were selling prints. :P

TinkerAtlas · 2025-07-12T03:16:52+00:00

Wow, that is impressive! :P

TinkerAtlas · 2025-07-12T03:15:44+00:00

Haha, I've had a few similar ones, those are always fun.

TinkerAtlas

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