Help with my Mk3S  

RE: Help with my Mk3S

We can probably walk you through some of the learning curve issues if you break them down - for instance, warping is a thing that happens, and there are approaches that help you with that - adding a brim for instance, can help with that.  Depending on the material, this might be all you need - one little setting in the slicer.

Globbing and stringing - welcome to PETG.  First layer live Z height is critical for keeping globbing, prints lifting from the plate, or prints not adhering to the plate in the first place.  Element of the learning curve here are live-Z setting (sometimes per print!), adjusting nozzle temp - different filaments have different ideal print temps.

Pictures for a specific question sure help move the dialog along.

RE: Help with my Mk3S

Thanks so much for this. I really appreciate your reply. I've tried adding a brim which hasn't helped. I've also used the Original Steel Sheet plate PA11 as well as the TF26, with and without a Pritt stick coating. I'm using PLA from Prusa. When I have tried to get a decent initial layer, I've used "PLA_S3D_calibration_surface_75x75mm@200um_v6.1" and "firstlayer_0.15mm_single_PLA_MK3S_3m" to get it right. Sometimes I get one or more of the squares globbing or not adhering whilst others are fine. And there seems to be no real pattern to the failures.

I was going to upload some pictures, but I'm not sure how best to do this? 

RE: Help with my Mk3S

The add media button, located above the ribbon and below the post subject.

First thing I'd advise - turn on 7x7 bed mesh leveling in the settings.  This will help with some of the inconsistencies across the bed.

The calibration is a "rough cut" where you get your live-z close enough to start a print once the calibration patches look like a good first layer.  But each and every print/filament combo might need to adjust live Z - which is done after the print has wiped and is laying down the skirt.  Click the button on the control panel, scroll down to adjust live-z and it will drop you into the adjustment window - counter clockwise gets you closer to the plate, clockwise gets you farther away.  The increments are in thousandth - so you can be pretty aggressive in dialing in a good live Z.

RE: Help with my Mk3S

Oh my goodness I'm soooooo stupid. I see it now.

Here are some recent examples...

RE: Help with my Mk3S

Those first layer shots don't look like you got good adhesion.  It also looks like you may be printing with no infill on the knobs?  No infill can cause prints to fail because the bridging on the top layer can lead to globbing on the print head.

That one that is flat that is printed on an angle with a raft - looks like you had challenges getting it level with the bed in slicer.  Use a design program with a great "settle" feature, and redo that STL/3mf so it fits flat and you don't need that raft/fill or whatever it is.  Where the globs are on that looks like there might have been a build-up glob (live z too close to the bed and dragging over the traces after first layer) that finally fell down later in the print.

For those big vice jaws - if brim didn't work, either add more brim, or punch some holes through the part so the long strands are broken up.  That one also looks to be nearly totally hollow - which could compound globbing on the top layers.

RE: Help with my Mk3S

Wow. This is really helpful. It's late now and I'm reading and replying in my mobile phone. Perhaps I can clarify some of this again tomorrow? 

Thanks so so much. Brilliant. 

RE: Help with my Mk3S

Just to clarify: are you printing PLA or PETG?

It’s not really obvious to me what we’re looking at in some of the pictures. E.g., is what we’re seeing in the last photo the bottom of the model or the top? If it’s the bottom, it’s clearly a serious case of bad Live Z.

You can also upload 3MF files of your models here but you have to Zip them first. This way folks can take a look at your settings and help improve them. As @dan-rogers has astutely observed, there are some aspects of your models and/or your settings that perhaps can be optimized. 

RE: Help with my Mk3S

You lot are wonderful. Thank yoooooo. It's honestly driving me to distraction. 

I'm using PLA. I'll try and get the "3mf" files uploaded shortly. Can you please give me a pointer? Is that the file that is on the SD card I load in the Prusa? I thought that was a gcode file?

RE: Help with my Mk3S

A .3mf file has all settings you used in PrusaSlicer. Like print, filament and printer settings. Others can open that file in PrusaSlicer and see exactly what you used to generate the gcode file that you used for a print.

The .3mf file is helpful for others to help you. But I use it for myself too and it is easy to recreate a print when I made lots of changes in PrusaSlicer. Or to use those settings for a new part. Just load the .3mf file and that load the new part in PrusaSlicer.

In PrusaSlice goto File > Save Project As..., and save the .3mf file. Now zip that file and upload it to the forums. It is to be zipped as that forum doesn't accept the .3mf file if you don't.

RE: Help with my Mk3S

I have to say, I think the print settings is the most likely culprit. I acknowledge that I might have got something wrong when I converted the Mk3 to the Mk3S, but I've redone it a few times now to double and triple check and I can find nothing wrong.

Here is the Blackout_Cover file.

RE: Help with my Mk3S

Don’t know. I don’t see anything wrong in the 3mf file. The only meaningful change seems to be setting the fan to full speed after layer 1 instead of ramping it up as in the stock generic PLA profile but I wouldn’t expect that to cause any issues with PLA.

Well, there is a mistake in the end gcode, it should be (if max_layer_z<...) as opposed to (if layer_) but that code is executed at the end and shouldn’t cause any issues  

So back to hardware issues. 

From the pictures it’s still not clear to me how good the live  z calibration is. In the middle pictures there’s what looks like waves but I’m not sure whether we’re looking at the first layer or what. The blob of filament could come from the nozzle dragging in filament as @dan-rogers suggested, or it could point to an incorrect hotend assembly with filament oozing because the nozzle is tightened against the heater block rather than the heat sink. 

RE: Help with my Mk3S

Posted by: @fuchsr

From the pictures it’s still not clear to me how good the live  z calibration is. In the middle pictures there’s what looks like waves but I’m not sure whether we’re looking at the first layer or what. The blob of filament could come from the nozzle dragging in filament as @dan-rogers suggested, or it could point to an incorrect hotend assembly with filament oozing because the nozzle is tightened against the heater block rather than the heat sink. 

I'm liking the whole answer. I've added emphasis to the bit that particularly interests me. I have had oozing before. In fact I've spent more time ensuring that is as directed (by Prusa) than almost anything else. I inserted the hotend heatsink into the heater block leaving 1/8" gap. I inserted the nozzle and butted it up to the heatsink and then tightened it.

I'm going to start the middle picture print again and take some pix of the progress. Perhaps that will help?

Eternally grateful for your time on this.

RE: Help with my Mk3S

OK so I started with doing another PLA_S3D_calibration_surface_75x75mm@200um_v6.1. The results below.

Next I'm reprinting the Blackout Cover and I'll upload the progress photos.

RE: Help with my Mk3S

OK so I just watched the first layer. There wasn't a lot of oint going any further as you'll see. I did notice a couple of things on the screen which was the Z number having a questionmark as you will see. Once the print started properly, the questionmark disappeared. Not sure I've noticed that before.

Anyway, the pics...

RE: Help with my Mk3S

Give the steel-sheet a thorough clean and try again.

Cheerio,

RE: Help with my Mk3S

Posted by: @rb14

 I did notice a couple of things on the screen which was the Z number having a questionmark as you will see. Once the print started properly, the questionmark disappeared.

I believe the question mark is there because this is before the bedleveling step. The printer doesn't know the exact height yet.

RE: Help with my Mk3S

Posted by: @baklin

I believe the question mark is there because this is before the bedleveling step. The printer doesn't know the exact height yet.

Exactly this. Until the printer has been homed to establish XYZ 0 positioning, which happens during the startup sequence, can only display where it thinks it is.

FWIW: You'll see a question mark next to the time remaining if you manually adjust print speeds with the front knob during a print.

RE: Help with my Mk3S

Posted by: @diem

Give the steel-sheet a thorough clean and try again. 

Thanks for this. The steel sheet is always clean. I keep a stock of antiseptic wipes for that reason. 

RE: Help with my Mk3S

Interesting this thread remains.  When your prints are having issues, are you re-playing old GCODE files that were originally sliced for your MK2?  Just wondering - cuz that could cause "hey, these gcodes used to work fine" - they need to be re-sliced for the new printer.

That white thing with the support or raft - why is it canted such that it needs support like that?  It can be the devil to get a canted bottom to really print well.  You want the bottom to be absolutely flat to the bed as much as possible - and that rafting over half of the surface makes me wonder if that surface is perfect zero or off by a few tenths of a degree.