Can you probe the bed with the nozzle colder?  

Yes, @bobstro has an excellent page on that topic
https://projects.ttlexceeded.com/3dprinting_prusaslicer_start_gcode_mk3.html

Thumbs up

I love to see this the default for the MK3 series directly in PRUSA Slicer. Oozing is rather annoying and led to bad prints. I now switch on the printer heat it up for 10-15min until oozing stops more or less. In my MINI+ I can just start and must not care.

You probably have moisture in your filament

As the filament heats up, steam pushes the oozies out.  Dryer filaments won't do this nearly as much.  Also make the change to the custom Gcode associated with any profile and you don't have to repeat it over and over.

thanks!

Thanks for the info everyone, I grabbed some of the start code from my Mini+, and now the Mk3 heats to 170 before probing the bed, and then goes to full temp, so the little blobs and bits are gone.

Can you please give an example?

Posted by: @mark-blasco

Thanks for the info everyone, I grabbed some of the start code from my Mini+, and now the Mk3 heats to 170 before probing the bed, and then goes to full temp, so the little blobs and bits are gone.

Hi Mark, I wonder if you would share how exactly you did that. Love to do that as well but I don't really have a clue where to start. Not a Gcode expert. Your help is highly appreciated!

Cheers Alexander

Just follow the link Ringarn posted to Bobstro's website and his page will take you step by step through the gcode and explain what each line does.  While Bob's example is for the Mk3 printer its equally applicable to any other printer.

Too complex for me.

Just follow the link Ringarn posted to Bobstro's website and his page

Thank you. I looked at that earlier and found it rather complex. It seems a lot of code needs to be added. I am more than reluctant to copy and paste what I see there because I don't understand it and I cannot say whether this is what my printer needs.

For me the PRUSA printer and slicer are merely tools that I use. 

I was hoping it is mainly two commands or so to put in somewhere. But I don't know what commands and where to add them.

Sorry for looking ignorant but I think I do more harm than good if I start tinkering with that. That's why I was hoping to get a clear instruction on how to do that. 

I wish PRUSA changes that in their general settings like in the MINI+ I have. This one just starts and prints 100% w/o blobs. BTW it's not only moisture (although it clearly contributes). I experience this since I started 3D printing 4y ago. Hence I started to heat the printer up until a line of roughly 10cm has built. I then clear the nozzle with a smooth brass brush and start printing, On the Mini this is just not necessary. So much easier. 

No it only looks complex because you aren't familiar with it.  Unless Prusa do update the mk3 defaults you are going to have to go into there and edit manually.

You only need to add in the section for the preheat.  However if you really cant follow the commented step by step explanation then I agree, you really shouldn't be touching it.  Its a pity though as putting some effort in and gaining even a basic understanding will stand you in good stead in general.

Thank you

I was hoping the forum would be there to help each other instead of telling users: READ & LEARN, stupid! 😂

But I can live with that. Make sure that you never forget that there are people out there in the world that either aren't as intelligent and capable as you are or ... just don't have the time to dive into a topic they are not really interested in. 

Best of luck for you!

Oh I understand that, its just that when it comes down to it that you can either blindly follow some instructions you find online or you can educate yourself and figure out what does what.

If all you want are the instructions then just copy in Bob's and be done with it.  Or someone can copy the same lines into the forum and you can copy :lol

Personally I'd always go for learning but that's just me.

RE: Sometimes pointing to an external knowledgebase is simply the best answer. Our time is valuable too!

Posted by: @alexander-3

I was hoping the forum would be there to help each other instead of telling users: READ & LEARN, stupid! 😂

I put that fully documented example together specifically to help out this community. We often get repeated questions on the same topic, so rather than spend my time re-writing or pasting essentially the same answer repeatedly, I put up a web page and focus on tweaking the information there in one place. I've gone to great lengths to explain each and every step as well as explain why. If you have questions, or something is less than clear, I'm more than happy to answer as best I can. However, we do ask that our time and constraints also be respected. Sometimes pointing to an external knowledgebase is simply the best answer. I can use features for documentation on my pages that simply don't exist or work well in a forum such as this. Don't take it as some sort of personal slight.

Who Has Called You Stupid??

@alexander-3

You have clearly not even clicked on the link I provided, and looked at the page? <-- Question
If, I repeat it for clarity, IF, it is so, then Yes, it is stupid to ask a question, ignore the answers and then jump on people (@neophyl in this case) for trying to help.
How should we know,
1: How MUCH You know and understand?
2: If You WANT to know and understand?
3: If You just want a quick fix?

Could you PLEASE answer these simple questions, How Should We Know?

Bobstro has a readymade startupcode for Mk3S, as Neophyl told you
Just copy/paste if You don't want to understand!
If You on the other hand WANT to understand, he has a very detailed description of how and why.

Remember the questions in this post!!

BTW, here is bobstro's code, copied, pasted, and unedited from the above linked page:

; PrusaSlicer start gcode for Prusa i3 Mk3
; Last updated 20210316
M300 S60 P10 ; chirp
M862.3 P "[printer_model]" ; printer model check
M862.1 P[nozzle_diameter] ; nozzle diameter check
M115 U3.9.0 ; tell printer latest fw version
M117 Initializing
; Set coordinate modes
G90 ; use absolute coordinates
M83 ; extruder relative mode
; Reset speed and extrusion rates
M200 D0 ; disable volumetric e
M220 S100 ; reset speed
M221 S100 ; reset extrusion rate
; Set initial warmup temps
M117 Nozzle preheat
M104 S160 ; set extruder no-ooze temp
M140 S{if printer_model=~/.*MK3S.*/}[first_layer_bed_temperature]{else}{max(first_layer_bed_temperature[0],80)}{endif}  ; set bed PINDA warmup temp
; Nozzle warmup before home to avoid driving hardened ooze into PEI surface
M109 S160 ; wait for extruder no-ooze warmup temp before mesh bed leveling, cool hot PINDA
; Home
M300 S40 P10 ; chirp
M117 Homing
G28 W ; home all without mesh bed level
; Present bed for final cleaning
G0 Z3; Raise nozzle before move
G0 X125 Y180 F10200; Move nozzle to PINDA warming position
G0 Z0.15 F10200; Lower nozzle to PINDA warming position
; Wait for PINDA warmup
M117 PINDA warmup
{if printer_model=~/.*MK3S.*/}
M117 Mk3S detected, no warmup required
{else}
M117 Mk3 Waiting for PINDA warmup
M860 S35 ; wait for PINDA temp to stabilize
{endif}
M140 S[first_layer_bed_temperature] ; set target bed temp
G0 Z3; Raise nozzle before move
; Mesh bed leveling
M300 S40 P10 ; chirp
M117 Mesh bed leveling
G80 ; mesh bed leveling
M117 Saving results
G81 ; save mesh leveling results
; Final warmup routine
M117 Final warmup
G0 Z5; Raise nozzle to avoid denting bed while nozzle heats
M140 S[first_layer_bed_temperature] ; set bed final temp
M104 S[first_layer_temperature] ; set extruder final temp
M109 S[first_layer_temperature] ; wait for extruder final temp
M190 S[first_layer_bed_temperature] ; wait for bed final temp
; Prime line routine
M300 S40 P10 ; chirp
M117 Printing prime line
G0 Z0.15 ; Restore nozzle position - (thanks tim.m30)
M900 K0; Disable Linear Advance for prime line
G92 E0.0 ; reset extrusion distance
G1 Y-3.0 F1000.0 ; go outside print area
G1 E2 F1000 ; de-retract and push ooze
G1 X20.0 E6  F1000.0 ; fat 20mm intro line @ 0.30
G1 X60.0 E3.2  F1000.0 ; thin +40mm intro line @ 0.08
G1 X100.0 E6  F1000.0 ; fat +40mm intro line @ 0.15
G1 E-0.8 F3000; retract to avoid stringing
G1 X99.5 E0 F1000.0 ; -0.5mm wipe action to avoid string
G1 X110.0 E0 F1000.0 ; +10mm intro line @ 0.00
G1 E0.6 F1500; de-retract
G92 E0.0 ; reset extrusion distance
; Final print adjustments
M300 S40 P10 ; chirp
M117 Preparing to print
; Adjust extrusion rate if desired
; M221 S{if layer_height >= 0.32}90{else}100{endif} ; compensate for thick layer heights
M117 Print in progress

Forums are not the best place for detailed technical breakdowns

Unfortunately, Prusa has removed the ability to paste in formatted code. And for some reason, basic things like bolding pasted code has been removed. Creating a bespoke response for detailed, technical questions is a lot more difficult and time-intensive than it was before.  

Interesting style of communication

You have clearly not even clicked on the link I provided, and looked at the page? <-- Question

A question mark alone does not turn a statement into a question. 

BTW "stupid" was taken from "keep it simple, stupid." I thought that this analogy would be clear, that's why I added the emoticon. Sorry for not stating it.

But thank you all for your effort. I did not copy that code into my PRUSA profile as it seems to do way more than I need. That was already evident when I looked at it the first time. I am sure it is great but it seems to do way more than I need. The only thing I wanted to have was the same behavior as the MINI+ I own. No frills, no diploma in G-Code. Sorry if this is not the attitude some of you expect.

Solved

Posted by: @mark-blasco

Thanks for the info everyone, I grabbed some of the start code from my Mini+, and now the Mk3 heats to 170 before probing the bed, and then goes to full temp, so the little blobs and bits are gone.

In the meantime I did the same. Added 6 lines and deleted 2. 

RE: 3 bears

Posted by: @alexander-3

 

[...] I did not copy that code into my PRUSA profile as it seems to do way more than I need. That was already evident when I looked at it the first time. I am sure it is great but it seems to do way more than I need. The only thing I wanted to have was the same behavior as the MINI+ I own. No frills, no diploma in G-Code. Sorry if this is not the attitude some of you expect.

So at this point:

1. If what you want is for the Mk3 to act like the Mini, you can just copy the gcode sample over wholesale .
2. If you want to learn what's going on, the fully documented pages should help.
3. If you just want the important parts of the 2-step warmup procedure so you can figure out where to paste in to your own gcode, those are provided as well. 

There are dozens of variations on startup gcode, so just plug in the bits of interest. Is there anything else we can do for you today?

RE: Thank you - Solved

Thank you @bobstro. That helped.

Gcode is not exactly "code"

Posted by: @alexander-3

Thank you @bobstro. That helped.

I had a much better time with gcode once I realized the "code" is misleading. 3D printers are profoundly dumb when it comes to "programmability". You have to tell it literally everything to do, and any calculations are all done in the slicer. Glad you got it going. Let us know if you have any issues.

HPGL

Thank you again. Yes. That reminded me of old HPGL if that rings a bell.