RE: MK3S experience leads to MK4 questions
Someone here posted a bit of GCode modifications to retract the filament before auto-leveling, and push it back in prior to doing the purge line. That has reduced the oozing considerably for me. These days, I just start my PETG prints unattended, oozies no longer being an issue.
RE:
I actually broke a hole in the layer on a smooth sheet when I had left it on when printing PETG and tried to get my print off. Lesson learned: do not try to force separation by cooling the sheet on ice. The sheet is a laminate with soft bonding and the shrinkage of the steel core will not carry on to the sheet top layer to which the bonding occurred. It does however put both the top layer and the adhesive below their glass transition temperature, resulting in the brittleness that can be expected.
I do not think oozing of PETG can be prevented entirely. All I know is that for me it got worse when the roll was left on for the night, and that it got better after a few days with the absorbent. I did same for a roll of ASA and put one of those 2$ devices into that bag. It gave humidity 'LO' which I take to mean it is less than the poos thing was set to measure. the absorbent was one of these: https://www.bison.nl/nl/product.6315088
RE: MK3S experience leads to MK4 questions
Someone here posted a bit of GCode modifications to retract the filament before auto-leveling, and push it back in prior to doing the purge line. That has reduced the oozing considerably for me. These days, I just start my PETG prints unattended, oozies no longer being an issue.
Any chance you'd be willing to find that thread and share a link here? I'd like to give it a try and possibly try to adapt something similar for pauses, to minimize oozing while pausing/resuming mid print.
-J
RE: MK3S experience leads to MK4 questions
Does it occur to anyone else how humorous some of these threads can become. @fabnavigator started off by mentioning that his primary goal was to print PETG with confidence on a textured sheet (paraphrased). I joined in because I too print primarily on the textured sheet with PETG. For us, the appearance of the textured surface is all important. My experience with the MK3 was very different than I'm getting with the MK4. On the MK3, once the z-offset for a sheet or nozzle change was dialed in, the textured surface was perfect. On the MK4. Without intervention, I havened got a consistent textured surface with PETG since I stated using theMK4, I've had numerous failures because the auto z-offset is often so high that the extruded filament never touches the bed. I'm spending more time with nozzle cleaning then I ever spent on Z-offset adjustments. That kind of nullifies the advertised benefits of the load cell, at least if I only print with PETG on a texture sheet. PETG is already difficult to print with because of it's love of water, and it how it sticks to the nozzle, but I've had great luck with it in the past. With user interventions that include cleaning the nozzle for every print, retracting filament before doing the bed mesh, printing a wide skirt so I can adjust z-offset for an adequate filament squish, I can get acceptable first layer quality. Having to tend to the printer for every print start is a new experience for me. The rest of the print is great, and I haven't had these problems when testing with PLA.
RE: MK3S experience leads to MK4 questions
@lynn, Great summary. Thank you. Humorous? I'm not sure I agree. Does Prusa know about this? I imagine they do. Maybe they consider our specific requirements to be on the fringe of what most users are looking for. I pretty much have the answer to my original question, and I'm not happy. It's not an inexpensive printer, and to have to futz with it more than the MK3 is a bummer. Could Prusa give us manual z-height adjustment like on the MK3? Yes. Will they? Probably not because it is an admission of failure. Can they fix the automatic feature to work properly for our conditions? Maybe, but I wouldn't bet on it.
So, this leaves me without a printer for now. I'm not happy about that either.
RE: MK3S experience leads to MK4 questions
@fabnavigator: A stupid question mzybe: do you use a silicon cap on the heat block? I did not. That may explain the difference. And if you do use one, in setup did you check the box you use one?
RE: MK3S experience leads to MK4 questions
Before I started reading this thread I didn't know I had a problem with my MK4s. 🤣
But I've only been using the Satin Sheets since they became available. They are perfect for PLA and PETG and everything sticks wonderfully. That wasn't the case with the Smooth or Textured Sheet, I always had to change depending on the Filament. I've also never cared how clean my nozzle is at the start. I send the print job to PrusaConnect and that's it. For me, leveling runs perfectly on both MK4s.
You can probably look for a problem and a solution anywhere, but the MK4 is a real workhorse for me. I also have the MK3s+, but I would always prefer the MK4.
RE: MK3S experience leads to MK4 questions
@efvee, No I haven't. Until very recently, I never heard of them. @lynn, do you use a silicone sock?
@smithy-2, I bought a satin sheet when they came out and tried it with PLA. I found that my prints were not sticking well enough. I don't remember how much contact area my models had. Recently I made some PLA boxes on the satin sheet and it worked very well. I'm glad the MK4 is working out for you. Any filament that ends up on the bed under the print when the print starts will leave an unacceptable (to me) blemish on the bottom of the model. But I can easily imagine that many people don't care about the perfection of the bottom surface.
RE: MK3S experience leads to MK4 questions
Any filament that ends up on the bed under the print when the print starts will leave an unacceptable (to me) blemish on the bottom of the model. But I can easily imagine that many people don't care about the perfection of the bottom surface.
Yes, that would really bother me too, but it has never happened.
I bought a satin sheet when they came out and tried it with PLA. I found that my prints were not sticking well enough.
I love these satin sheets, a real all-rounder for me and I've never had a model that didn't stick. I also have the Satin Sheet on the MK3, which is also a winner.
So if you don't necessarily need the texture of the Textured Sheet, I would only use the Satin Sheets.
RE: MK3S experience leads to MK4 questions
I can't find the thread, but the following are the lines from custom Start G-Code (modified values in red)
{if filament_type[initial_tool]=="FLEX"} ; MODIFIED for extra retraction
G1 E-34 F2400 ; retraction
{else}
G1 E-32 F2400 ; retraction
{endif}
...
G1 E{(filament_type[0] == "FLEX" ? 40 : 38)} F2400 ; deretraction after the initial one before nozzle cleaning MODIFIED for extra retraction
RE: MK3S experience leads to MK4 questions
I'm curious to know what is keeping you from just buying an A1 or P1S? I haven't done much research on problems with them because I don't own one, but it at least seems that the prevailing opinion is that aside from the company philosophy issues that some disagree with, they make fantastic printers. You even mentioned the silicone wiper on the A1 in this thread. They are quite a bit cheaper, so why not just go grab one instead of going without a printer? Especially if you only print PETG and likely won't need an enclosure or (I think) the slightly higher temp bed of the Mk4.
-J
RE: MK3S experience leads to MK4 questions
@teamd3dp, I've thought about buying an A1. My biggest concern is giving an IoT device access to my local network. If I could connect it to my guest Wifi, I would probably buy one. From the research I've done, that doesn't seem possible. I'm also somewhat concerned about how much noise it makes. And the reported poor support. For $400, if it doesn't last for years, that's probably okay. By then there will be other options. I would prefer to get the MK4. If Prusa had kept around the manual z-height setup as an option, I wouldn't hesitate.
RE: MK3S experience leads to MK4 questions
And if you do need an enclosure an X1C is about the same price as a mk4 plus a Prusa enclosure and gives the option of multi filament now rather at some indeterminate time in the future.
RE: MK3S experience leads to MK4 questions
So why did you sell your mk3? From what I've read the only significant "advance" is the auto leveling.
If Prusa had kept around the manual z-height setup as an option, I wouldn't hesitate.
RE: MK3S experience leads to MK4 questions
It looks like there are a number of good improvements on the MK4 besides auto leveling: https://blog.prusa3d.com/announcing-original-prusa-mk4_76585/
I have nothing against auto leveling if it works. Who wouldn't want that? I launched this thread in an attempt to find out how well it works.
RE: MK3S experience leads to MK4 questions
I do use the silicon sock, and since the satin sheet is such a favorite in this thread, I can say that the satin sheet works for me as well, but without the texture of course.
I disassembled my MK3 for this upgrade and I won't go back, but the textured sheet problems are annoying.
RE: MK3S experience leads to MK4 questions
Maybe I'm feeling a little better about the MK4. I don't print every day, and I already have a satin sheet. I sold my textured sheet with my MK3 thinking I would get a new one with the MK4. The look of the surface from the satin sheet is probably okay for what I print. Maybe I'll hold off on buying another textured sheet if I order the Mk4.
Thank you all for your comments.
RE: MK3S experience leads to MK4 questions
I haven't needed to look into it because I use the smooth sheet, using windex to clean/allow release on the PETG side...but it seems like I've read somewhere that there is a way of fixing a z-offset somewhere in prusa slicer that can be used as a persistent adjustment...are you guys saying that the slicer adjustments don't allow this? Obviously the print tuning on the printer itself is not persistent between prints...but there really should be a gcode related adjustment that will apply only after the bed probing occurs while printing, for those needing this for the textured sheet. If not, I wonder if adding such a feature feels like a liability to Prusa since it could open the door to bed damage if misused by inexperienced folks. Who knows.
-J
RE: MK3S experience leads to MK4 questions
Also, if the z-heights looks great, but adhesion is worse on the mk4 vs the mk3, my guess is the solution (once temps are calibrated etc.) is to simply set the first layer speed to something like 30mm/s, which is slower than the stock mk4 profiles calls for. I've been doing this as a standard and I feel like it keeps things sticking well.
-J
RE: MK3S experience leads to MK4 questions
Must admit that since reading this thread I have cancelled my plan to buy a texture sheet.
Maybe I'll hold off on buying another textured sheet if I order the Mk4.