I've been having problems printing on my CR-10S for several months now. I couldn't get anything properly filled unless I cranked up the extrusion multiplier to 600%. That can't be right. And even at 600% extrusion rate, parts still would look underfilled on the bottom layer, and wouldn't stick to the bed as a result.

I'd fairly recently had an extruder failure, so I upgraded to a direct drive unit. I replaced the broken part and reverted back to the original extruder. Double- and triple-checked my esteps on both extruders. Nothing. I thought maybe there was a problem with my firmware (I've used Marlin for some time), so I reverted the last couple of changes I've made. No change in print quality. Checked all the general maintenance items: belt tensions, carriage eccentrics, lubed the lead screws, still no joy. Multiple different nozzles, 0.2 to 0.8mm, replaced the thermistor, even back to the stock 40W cartridge with a PID tweak (I've been using a 60W cartridge for a while). No improvement at all.

The one thing that always printed well was the purge line at the beginning of the print, which is pretty much hard-coded in the g-code, so it didn't really seem like there could be a mechanical or functional problem, and I really couldn't find any. I finally wound up on Ultimaker's Cura website, desperately looking for anything I could find. They mentioned something about how the latest revision's changes were mostly intended to save us filament, and that didn't sound good to me. How can you save filament except by extruding less? Don't do that!

Long story somewhat shorter, last night I installed Prusa's slicer and printed up a benchy using all the default settings. It's perfect. Maybe a TINY bit under-extruded, but that's probably because of my esteps, which I think is just a tad under due to my experiments.

Has anybody else had anything similar happen to them? Ultimaker may have had good intentions in trying to save us filament, but for me, what they did was remove my ability to control the extrusion. Now that (I think) I understand what to look for, even when previewing the g-code in Cura, it's clearly underfilled. IMO, they need to stop trying to make decisions like that for us, and allow us to control the machine properly.