Nozzle catching on prints wit new build  

RE: Nozzle catching on prints wit new build

Examine the underside. If the adhesion is poor either due to your Live-Z being too high (not negative enough) resulting in a rough 1st layer with gaps between extrusions, or bed contamination (finger schmutz) leading to poor adhesion, the part will shift and raise up, giving the impression that the nozzle is dragging.

It is possible for the nozzle or fan shroud to drag, but you want to eliminate other causes first. This is a common problem that can be caused or aggravated by two factors that need to work together well for successful prints. Here's mama's tried and true copypasta recipe to get you going...

• A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. If it's a smooth PEI sheet, take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails , and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. Rumors persist that some tribes deep in the jungle have had good luck getting started with these sheets by giving them a wipe with 100% acetone and a dunk with Dawn. Either way, there's no real warranty on these sheets. YMMV.
• If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. It's much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers.    

RE: Nozzle catching on prints wit new build

Also, take a look at the fan shroud.. This is the piece that connects the part cooling fan to the extruder. It partially encases the hot end heat block. I has this problem once when the shroud neck broke, not sure if it was during installation or sometime after. The shroud was literally dragging across the surface. I printed a new one and replaced and no more problem..

RE: Nozzle catching on prints wit new build

I cleaned the base, and adjusted the nozzle further down, it solved the problem mostly, but the rest of the issue is the model I was printing had items without supports it was trying to print (this case a tail) so nothing to build on which was causing extra filament to come out and was grabbing the other pieces.

I think the live-z adjustment solved it, I just need to get more familiar with it in general. I was having issues sending things to the printer directly from the computer, but after a restart I'm not sure if that will still be an issue as I converted something to gcode and am printing it right now (so printer is busy)

Thanks for the help!

RE: Nozzle catching on prints wit new build

Turn nozzle heat up. And make sure its clean first layer