I have been trying to figure out how to make my printing better. I am using petg exclusively and haven’t been able to zero in on how to get sometimes even reasonable prints. I have an Ender 3 S1 Pro that I just upgraded to the Sonic pad. I have been trying to get a better feeling for the print speed issue between marlin and klipper but kept getting these blobs on my prints. I have replaced the ‘Sprite Extruder Heater Block’ twice now. I sometimes get a blob of plastic around the nozzle and couldn’t figure out if it was coming because the nozzle was not tight enough or something else, so I just decided to replace the entire heater block again. When I took the heater block off this time I took a picture of the blob in top of the heater block.
I have a hard time understanding how this happens or what I can do to prevent it. Last time I replaced the heater block it was because I torqued the nozzle into the heater block too tight and it stripped the threads. I wish there was a torque wrench to know how tight to get it. At 180* its easy to tighten too much.
I sure would like to understand how that blob of plastic could come from the top?
You might want to consider setting up a web cam to record the whole printing process. If you can get a video of it, you (or someone on the web) might be able to figure out what’s going wrong.
I’ll bet the sonic pad has provisions for controlling a camera.
I set up an old web cam on my klipper pad for my ender 3 S1, and it works well, except for a somewhat slow frame rate (I’m not sure whether that’s the pad’s fault or the camera’s)
The main rule is to (re)assemble the print head while it is hot. Metal is expanding when heated up and former tight screwed parts get loose.
As a result the plastic pushes along the threads and gaps instead of following the path to the nozzle. The result is a blob of plastic around the entire heater. It may work for a few print hours but the loose print head parts will leak more and more due to the vibration.
Depending on the type of heater block, nozzle and heating element assembly might variate.
Typical is that you screw in the nozzle first and loosen it around half a rotation. Now you screw in the cold end from the other side until both touch. Now heat up the heater to 200°C and tight the nozzle against the heat pipe inside the heater block. Just avoid overtighten here. In hot state less force is required.
As you screwed the block in heated state it cannot loosen up and gets even tighter when cooling down. I common problem is that people are over tighten the components in cold state, but the heat will loosen it anyway. So tight the connection in hot state and with a sane amount of force.
Some crappy cheap heater blocks are not made from aluminum. The from Chinesium (funny word creation to describe cheaply made metal compositions), which is soft like hell. These may break and crack over time and plastic is able to flow out that way. You can easily check if the block is cheap, but clamping it. When the teeth get visible within the metal it is crap.
I recently made a chance find-and-tweak for PETG. I too was suffering from seemingly inexplicable surface artifacts … what I thought of as blobs. Thought these were retraction related … and just couldn’t dial it out. When I came across ‘infill / wall overlap’ setting in OrcaSlicer. I reduced it from 30% to 10% … and the difference was like night and day. Artefacts gone !! Setting can be found under ‘process’ / ‘strength’ / ‘infill’. See if this helps … or not.
Do you get any witness of similar using and other filament type / brand ? PLA, TPU, ASA, etc? Is there any difference between brands of the same type ? Do you think the thermocouple is correctly measuring and reporting temperature to the controller ? Is / are the cooling fans working and operating per profile, i.e. fan speed %, coming on/off at specific layers? Is the silicone sock causing any reason for material diverting from the plate? Are you having any bed adhesion issues … in other words if the material is not sticking … then it has to accumulate somewhere … unpredictable ?
