Having Issue with Over extrusion, please help

[jazzsingeruk 0]

SO I have been trying to print this for over a week now and every time i do i get it back streaky and whispy,

I have extraction turned on and tried multiple settings but im flabbergasted why this is happening.

 

My Printer is an Anycubic Mega S.

 

Any help on how to fix this issue would be appreachiated.

 

Thanks

 

 

[gr5 2,167]

I think you mean retraction, and not extraction.

 

Anyway I'm guessing you have stringing but I often spend 10 minutes writing detailed explanation of how to fix stringing only to find out the issue is something else so...   please show some photos of what you are talking about.

 

If it's wispy enough though you can probably remove most of it with an open flame - it's amazing how those wisps just dissapear within about 1/20th of a second.

[jazzsingeruk 0]

These are what im getting out

[gr5 2,167]

Oh yeah - that's pretty bad.

 

What kind of filament is that?  Is that polyalchemy?  It looks just like it and I also find that strings more than usual (but not this bad).  Also know that white filaments tend to string more.  I don't know why - some additive.  Doesn't matter manufacturer or even PLA versus PETG - they all seem to print worse in white.

 

So make sure it's actually retracting - there are several features that limit quantity of retractions in cura so look at it in PREVIEW like you did in the screenshot above except change "color scheme" from "material color" to "line type" and then make sure you have the blue colors enabled (moves checkbox).  If you look carefully you will see there are light blue and dark blue lines for moves.  Dark blue are non-retracting moves.  Light blue are retracting moves.  See if your strings are on non-retracting moves.  If so there are settings to change in cura.

 

If not then you need to adjust other things.  You want to lower the pressure in the nozzle which means print slower.  But also you want to increase viscocity to reduce dripping/stringing so lower the temp.  Maybe 200C is cold enough.  Maybe you need 190C or even 180C.  If you lower the temp that much you also need to slow down more.

 

Make sure you travel speed is fast.  Like 200mm/sec if your printer can do that.  Most can.  Make sure the acceleration settings on the printer itself is nice and fast and maybe incrase the acceleration of the feeder so the retraction happens faster.  Also maybe increase retraction speed in cura.

 

I recommend doing two towers next to each other as a test part to try to reduce stringing before printing something larger like this.  That way you can go into the TUNE menu of your printer while it's printing live and adjust some of these (temperature, feedrate).

[GregValiant 1,245]

@gr5 - it could also be a Silky PLA.  I've had the same problem when it has a high moisture content.  Drying it out helps a lot.  (And I'm a believer that everything runs in streaks, and if true that it's a Silky PLA then this would be the second Silky thread in the past few hours).  When extruding prior to printing, if the Silky comes out of the nozzle and immediately expands to about 4 times the nozzle diameter, that would seem to indicate high moisture content as the water turns to steam in the hot end.

 

@jazzsingeruk - you used the word "wispy".  Would that equate to "cotton candy"?  I've noticed that some nozzles do that much more than others of the same size.  It's like they shoot up a roostertail of plastic when they print and it blows all over the place.  It's so fine I haven't been able to measure it, and grabbing it with a tool (or even with fingers) is almost impossible.  Just changing nozzles probably wouldn't effect all that regular stringing though.

 

I had a couple of good photos of a silky print taken before and after drying the filament.  The difference was quite noticeable and it was the same Gcode file.  Unfortunately I cleaned out the folder and the photos are gone.

 

 

 

 

[geert_2 557]

 

7 hours ago, GregValiant said:

...

I had a couple of good photos of a silky print taken before and after drying the filament.  The difference was quite noticeable and it was the same Gcode file.  Unfortunately I cleaned out the folder and the photos are gone.

 

 

 

 

 

If you have them on a server, you have a chance of getting them back: on most servers there is "shadow copy" software running. When deleting or modifying a file, it keeps a copy of previous versions for up till one year, in a hidden folder. On our systems it is named "~snapshot".

 

A bit similar to the Windows Recycle Bin, but then with different file-versions too, and not so easy to delete as emptying the bin.