Z shift - gap on layers after M600 filament color change (VC4 500)
Hello, I am having this big issue where after a filament change (M600), the print presents a pretty big gap at the layer of change. Could it be a problem with the Z motors or software related ? How could I debug/fix it ? It's really ruining all my prints, both ABS and PLA.
It always worked well and made dozens of prints with the swap and following layer fusing perfectly.
Could be the Z steppers or some mechanical issue on Z ? Unfortunately a few times I printed full height objects and in the following prints the start macros made the bed go down beyond the lower rods limits and I heard the motors cranking badly :/ . Something happened in that moment maybe ? I really need to fix this, any help or inputs greatly appreciated!
8 Replies
I'm also seeing this when the printer pauses for a filament change.
Never happened to me before, did it a dozen of times . Maybe a firmware update ?
Rolling with a fully up to date machine. It could thinking about be related somehow to the filament sensor?
I'm not using a filament sensor. I have a stock hybrid vcore4 500
How much time has elapsed since the printer paused and you loading filament and resume?
If the printer pauses for a long time, the temperature of the parts will change due to the pause position. This causes differences in thermal expansion and when you resume printing you will see this in form of a pause shift
As I tried pausing the print I had a similar issue. I found that the head oozed a little. So before resuming the print I just extruded a little at pause position and then immediately resumed printing. Maybe this helps.
From my experience it’s just as long as it takes to remove the ejected filament and feed another through the PTFE to the extruder.
Which would rule out the filament sensor in my book.
For the cube it was a few minutes. For other products it depends it can be from 15 minutes to an hour (I launch bi-color long prints at night trying to swap in the morning). I have "external perimeters first" active in PrusaSlicer so that it's even worst.
The nozzle (and bed/ bed chamber) stays hot and I push manually a bit the filament (equivalent to what Klonk says), cleaning oozing right before pressing Resume.
I've noticed that swapping to a brand new nozzle improved results, but I can still see a nasty "seam" and the bonding is weak, probably for the temperature reasons you are mentioning even though I had great layer bonding results in the past when the machine was new.
I am printing ASA and my products must have two colors, one on the bottom half and one the rest.
Shall I move the Z-offset down 0.3 or so whenever I resume then ? Any other solutions (apart of IDEX) ?