Problems with first layer with multicolours-PETG  

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Fisherman
(@fisherman-2)
Active Member

I had a perfect first layer, working very good with waste block and model, I went ahead and did some modifications (horizontal MMU2 placement, M10 adapters on the PFTE tubes (inlet MMU2 and extruder head), due to load/unload errors. But none that would affect Z-cal. at least very much).

I tried printing after my mods, and are unable to get first layer correct. Have tried same g-code as before mod, but the results are terrible. 

I calibrate Z, and are able to get good results. But as soon as I start a print, it seems I get warping, looks like the nozzle are dragging the filament away from the bed.  Look at the attached picture of a gear with multiple colors. This is one of many attempts, usually the waste block is in much worse condition, and when I tried to get a complete first layer, I get the center gear and the white ones, the remaining are ripped away by the nozzle, either due to not sticking to the bed or filament buildup on the nozzle (I'm guessing). 

You can see in the picture that the perimeter has been ripped away in some places as well. 

 

I also get a lot of filament build up on the nozzle. 

I've tried to start printing with a lot of different  z-heights, but the result is pretty much the same.

 

I'm thinking to maybe increase the nozzle temp by 5-10 degrees, I'm using 230 today on first layer. 

One question, could /would the filament be acting like this because of humid weather? I'm grasping, but I'm still able to calibrate perfect Z-heights, using inbuilt calibration or using the 75x75 print (My-way).

The good thing, all my mods have given me no unload/load error, 20 hours print. But, here the first layer was all in a single color, seems I'm sometimes able to get a ok start on those.

I'm totally lost at the moment. Hope the community can guide me in the correct direction on this. 

🙂

 

This topic was modified 8 months ago by Fisherman
Posted : 26/10/2020 11:28 am
JoanTabb
(@joantabb)
Moderator

@ Saugh, 
Are you using 7x7 mesh bed levelling?  

the nozzle can pick up PETG if the levelling is not good, or if the printer is overextruding.  (Over extruding is not normally a first layer issue, unless you accidentally put a LARGE number in the extrusion multiplyer... this is something I did, (And reported to Prusa Developers)  and has been resolved to cause an error message in slicer 2.3.0...)

It's available through the LCD Menu system...

I am guessing Pablo didn't get his MMU2S to print, 

I did get mine to print, (I also got the MMUv1 to print, and the Palette 2S pro...  )   they all have idiosyncrasies,  but they can all be made to perform, if you have the time, patience and aptitude...  

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 27/12/2020 9:09 pm
Chris C liked
Fisherman
(@fisherman-2)
Active Member

@joantab

Thanks for your answer. 

I've reached a point now, where I can print with my  mmu2 without errors at all. 

 

Only issue I'm getting is when the filament roll is getting low on filament. Don't know why, light weight or old filament.

I have my filament rolls on top of my printer. So the biggest improvement I did was to place the mmu2 in a horizontal position.

Posted : 28/12/2020 11:37 am
Chris C
(@chris-c)
Eminent Member

@fisherman-2

What mod is where you put it horizontally, and what were the benefits?   I agree with Joan I have both Palette 2Pro and the latest MMU2 now for 2 months.  I can say that the learning curve for the Palette 2Pro is lower than the MMU2.  The MMU2 is not exactly an out of box kit that works,  there is a lot of tunning and trial and error, and reading that is required and not very straight forward and or systematical.  

However, as Joan has mentioned once you understand how each works, nuances, and how to tune them they both have strengths in creating MMU prints.

Oh, and one last thing.  If your printer is not working consistently before you get either machine, they will only compound your issues.

 

This post was modified 4 months ago by Chris C
Posted : 05/02/2021 1:26 am
JoanTabb
(@joantabb)
Moderator

@chris-c-2

🙂 

Was your printer working correctly before  to added MMU and Palette? 

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 05/02/2021 2:23 am
Tobbe
(@tobbe)
Active Member

I know this is an obvious question but have you cleaned the bed properly with isopropyl alcohol?

On the textured bed fingerprints and grease is a lot harder to see so it might be worth making sure it is properly cleaned first and then see if it changes anything.

Filament is never going to stick properly to the bed where there is fingerprints and similar.

Posted : 05/02/2021 11:42 am
Chris C
(@chris-c)
Eminent Member

@joantabb

 It was working but I knew that it was not perfect,  Z-layer and the surrounding temperature and humidity were varying in the location I had the printers setup.  So I got inclosures, dehumidifier, and humidity/temperature meters.  I also made sure my filament we kept dry.   If found out pretty quick when working with these devices they are a bit more sensitive then just the printer.  With the Palette if you leave the cover on or cover of you need to adjust your profile appropriately because with the cover on it is recommend a change in the cooling profile and with MMU2 the MMU2 I notice a difference if the Filament was in the inclosure vs out in the open and or out of a dry box played a difference.  Another thing I learned is people are using these dryers while they are printing which increases the temperature of the filament which I noticed that it through both my Palette and my MMU2 off....Battle scares...a whole week of them....and now both work well.

Posted : 05/02/2021 9:01 pm
Diem
 Diem
(@diem)
Honorable Member

@fisherman-2  I've just looked at the picture you posted.

Your first layer 'Z' is way off. It looks like something you did has completely eradicated your setting: Restore the default settings,  go through the first layer calibration again and get enough squish to make it into a one layer thick sheet.  Try printing after that and post pictures of your first layer or the bottom of the print.

Cheerio,

Posted : 06/02/2021 1:29 am
mc_ott
(@mc_ott)
Active Member

@fisherman-2, you may have solved your 1st layer problem but just in case!

I used to have issues with PETG and even PLA 1st layers, what works in my case is washing the flexible plates with dishwasher "detergent and lots of water" occasionally ( every 3-5 prints, your mileage may vary!) and avoiding putting fingerprints on the surface. Also in my case I noticed, the adhesion is less for prints closer to the edge of the flexible plate. A quick plate surface temperature test showed a variation of up to 10C degree from center to edge. To prevent items close to steel plate edges (such as the Waste Tower) coming loose, I also set my Hot-Bed to 70C for PLA and 90C for PETG. Also, I noticed, a Tower generated with "No sparse layers" checked has better adhesion to the plate, the only thing is, Prints and Tower should be carefully placed to avoid collisions as printing progresses. Hope this helps.

Posted : 22/03/2021 4:34 am
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