Help! Top surface line when ironing (with z-hop). [2×Creality Hi]
Every time I iron a print, I get a line like this, which I assume must be from nozzle drag; a dangling filament line wouldn't only be on the top surface, right? And, to touch, it's completely flat—no extra material is there that I can tell. It feels very slightly lower.
I have tested on my Creality Hi and my friend’s Creality Hi. My friend’s Hi seems to work better with 0.97 flow rate, vs. mine at default 0.98, so the ironing calibration is different, but the drag line is almost identical. (It moves up or down by ~1-2mm between tests, but it's the same angle and length across the same squares.)
Calibration is completed before printing.
I initially thought this looked like wiping, but I disabled wipe while retracting to off (with z-hop of 0.4mm) and this still happens. In retrospect, that makes sense, since wipe while retracting should be like 2mm, not across an entire print like this.
I then did some Googling and people online were suggesting bumping z-hop from off or 0.2mm to 0.4mm or even 0.55mm; I had 0.4mm already (the default setting), but I bumped it to 0.6mm (pictured above) and the drag line is identical. (Note that I forgot to take a picture before popping it off the plate, so please ignore the gap on the left. It was well adhered.)
Others also mentioned dragging from over extrusion; this is a crazy thin print, too, so there's no way over extrusion would be causing z-level imprecision this close. And with my friend’s Hi at 0.97 flow rate, it’s slightly under-extruded, if anything (occasional tiny line gaps in some spots on first and top layers, but better than the fused joints I was getting previously.)
FWIW, these tests were all done with JAYO basic PLA, but I get similar lines with other filaments when I use ironing.
What am I missing? What's causing that drag line? It's driving me crazy, and my Google Fu is coming up with nothing. Any tips?
What does your end G-code look like? Since it's a single line, I think it's most likely made when the extruder moves from the last ironing move to the park position
Yeah, specifically the end g-code your slicer adds by default. I bet it doesn't lift before parking. And no other slicer settings correct it since it's a fixed sequence tacked on the end.
That makes complete sense! Thank you. I think I have a fix, so including details below for future potential searchers:
The end of my g-code looks like this:
The first section shows z-hop (of 0.6mm) is enabled, as it moves to and from Z1.16 / Z1.76, and that it is doing a wipe on extract over and over again without affecting apparent print quality, as most ironing test patches look great. So, this confirms that z-hop is on (I'll revert to 0.4, the default), and that Wipe while retracting is likely safe to leave on (default setting).
The problem is the
; filament end gcodesection. As we can see from the Ironing g-code, it never changes from Z1.16. This confirms that @[email protected] and @[email protected] are correct; Creality Print does not add z-hop on the last layer.The fix, I believe, is to change the Extruder's Machine end G-code from:
to: (comments unnecessary, of course)
Thanks for your help!
Exactly right! Glad you figured it out :)
Before long you'll be tweaking your start routine to absolute perfection ;)
A word of general caution: be very careful with G90/G91, the oopsie of "I thought there was a G91 before this
G1 Z-2and now I have a little crater in my plate" is not a fun one to have, ask me how I know. I'm not saying you should try to avoid them as you would be limiting your routines a lot, but for example I like to add an empty line before every G90 and G91 block to "highlight" it