How to predict stringing; ideas

lets say i want to print an eiffel tower; the models i have seen look to have a lot of stringing potential;
how to guesstimate beforehand printing a long-running large print ?
an idea:
-take the full size stl, say it’s 15 inches tall
-import into meshmixer
-plane cut so just the top say inch remains (any section that you guess the stringing might be a player);
then make-colid, then align;
-export binary stl

  • in cura set the retraction distance and speed;
    -assess the results
    -tweak retraction settings if necessary and re-do
    -loop until just right
  • set retraction settings on the full scale model

is that right ?
any other/better/easier ways ? ( i am assuming that the stringing will be totally dependent on the scale chosen for the ‘full-model’ ( individual pla spools aside ))

Hi there,

There aren’t really any good ways to predict stringing, it is chaotic at best and doesn’t follow any commonly discernable patterns. So predicting it inside of a print is going to be difficult, the only thing that you would realistically be able to use to predict stringing is just if there is a gap that the nozzle is traveling between.

As for tuning your retraction settings properly there are some tools that can be used to find the right retraction distance, I have included one below which you might find interesting.

Happy Printing,

thanks matthew ofr the input; will try out those ideas;
i read somewhere seemingly credible that the retraction setting should never equal or exceed the nozzle Length
on my flsun v400 ( the 400 name is for the max travel burst print speed ) i contacted flsun and asked what the nozzle Length was , they said 21 mm; but then they said not to exceed ± 3mm from the printer profile settings in cura that they provided; i already had changed that default from 6 mm to 9 mm, so i was disappointed, am i to assume that the penalty for specifying too much retraction (distance) is nozzle clogging ?
also, any advice on the retraction speed ? i changed their default up 50% (more or less arbitrarily)
i believe that is a volcano nozzle)

you would have to temp tower to find the proper temp for the filament first. Once that is complete you would do a stringing test and you will get your strings to zero.

Hey there!

I feel like I had heard that before as well, usually I just end up doing a stringing test for each of my filaments and that is the deciding factor for me. Like Jason said make sure to do your temperature tower first before you do the stringing test.

For the speed I usually just leave mine stock, if I find I am having problems I will tweak it but generally the stock setting has worked well for all my stuff.

Happy printing,

ok, i appreciate the inputs; i will print the temp tower and use it (all3dp has a good link to a good temp tower);
still it seems this would be spool-specific, so in theory you would have to print a new temp tower for each spool;
i guess maybe only for intended model prints that look particularly potentially stringy

1 Like

question regarding the temps;
maybe a general question;
my anycubic korba plus is rated for 130 mm/s overall speed but the supplied Cura printer profile defaults to 80;
the temp on the profile is i believe 190;
i upped the speed to 100 and since i upped the speed i upped the temp to 210;
i had read somewhere that these newest high-speed fdm printers capable of (supposedly, 600 mm/s) were coming equipped with printer head/nozzle/extruder assemblies that were running at higher temps so that that assembly “could keep up”;
that is why i raised my temps when i raised the speed;
is this understanding true or am i arbitrarily raising the temps for no good reason and maybe that is why i am getting the stringing ?

Hey there!

Your half right, when printing at higher speeds it is generally a good idea to up your temperatures. But for the speeds you are printing you shouldn’t have to up them at all. The reason they are upped on the faster machines is to increase the flow rate of the nozzle. These crazy fast printers like the X1C, P1P, and K1 (potentially?) are going like 10x as fast as your printer will be. This could definitely also be a factor into your stringing, if you are printing too hot when your printer doesn’t require it the filament could become too molten and cause extra stringing. For my printers I usually run 200 for pla.

So basically yes you are right in that if you go really fast you should raise the temp, but for your current settings I wouldn’t worry about it :slight_smile:

Happy printing,

thanks matthew; i will drop my print temps back down

No problem!

Let me know how it goes and if you have any more troubles don’t be afraid to reach out!