3d printing can be a challenge. Lots of problems can come from just a simple print. There’s under extrusion, layer shifting, clogged nozzles, loose belts, z banding, etc. Because 3d printing is still in it’s infancy, we can’t expect early machines to be perfect. Heck, we cant expect a lot of things to be perfect. Luckily fixing these issues with your 3d printer isn’t as bad as it may sound.
Blobs on your 3d print look like unsightly pimples on the surface of your 3d print.. It’s caused by over extrusion of your filament. Basically the printer laid down too much plastic at that given point which caused the blob to appear. It’s very similar to z banding.
There are a few reasons why the nozzle laid down too much plastic on your 3d print. Lets explore some of the ways
If your print has blobs and zits generally you need to adjust your retraction settings. The extruder is just pushing too much plastic at any given point. Just go to your extruder section of your slicer and adjust it there. Here’s how you adjust it: say your retraction settings are .5mm and the extra restart distance is -.1 mm, then every time the extruder stops, it will retract .5mm of plastic. But when the extruder starts extruding again, it will push out .4mm of plastic out.
When the nozzle stops at a certain point, the extruder shouldn’t be laying down plastic. This is where your coasting settings come in. Your coasting settings stop the extruder right before the end of a perimeter. You need to increase the value of the coasting setting until you no longer see blobs in your print. Generally you need to adjust your coasting when all the blobs are at the same spot going up vertically on your print(this is if your start and stop print is at the same place). The main reason why we need coasting settings is because pressure builds up in the nozzle and we need to alleviate that pressure as the nozzle is coming to a halt. Otherwise, the nozzle will continue to extrude plastic at the end of it’s travel, leaving too much plastic at that particular point.
Blobs on a print isn’t a big deal. Normally, you can actually just take your nail and pick off the blobs and zits. But who wants to do that every time they print something? Is it really a big deal? Not really, but there’s something extremely satisfying about getting a perfect print right off the bed. You can also just smooth out the 3d print using several different methods.