Improve Print Quality - Remove Stringing

[maxpartenfelder 5]

Hello Ultimaker Forum,

this is my first post here, since I just got started using my brand new Ultimaker 2+.

Nevertheless, I have been a fan of 3D printing ever since.

Yesterday, I started a print job of a puzzle (see rendering attached) and wanted to go really slow to see how good the quality of the printer can be.

The model ist just about to finnish as I am writing this (took around 12 hrs to print although it isn't really that big).

The parameters of the print were the following:

- 0.4mm Nozzle

- 0.06mm Layer Height

- 22% Infill

- 20mm/s Print Speed

- 30mm/s Travel Speed

- Support with Roof touching Build Plate only

- Retraction: 4,5mm @ 25mm/s

On the printer I adjusted the printing temperature of my ABS (FormFutura EasyFil) to 255°C, I used the Heated bed just for the first hour or so and turned it off afterwards and in the middle of the print, I corrected the Material Flow fro 107% to 100% because of what I thought to see is overextrusion.

Maybe it is also related to the retraction of the filament, because it only appears on respectively one side of each "pillar".

Some help finding the problem, some analysis of the model or any kind of advice is appreciated!

Thanks in advace,

Max

Edited July 12, 2016 by Guest

[SandervG 1,521]

Hi Max,

Welcome to the forums! You picked a challenging model to start your 3D printing adventure with What you are seeing on your print is called stringing, and it is only on the inside of your print because it is being dragged along with the printhead during movement. The head doesn't travel outside of the model.

Usually stringing happens when there is an imbalance in printing temperature and speed. So I would recommend to print a little bit faster and see how that affects the print. When you significantly increase or decrease either speed or temperature, you should change the other value accordingly.

Good luck!

[maxpartenfelder 5]

Hi Sanderv,

thanks for the reply!

Is there a magic rule of thumb for balancing speed and temperature?

Something like "Temperature = x * PrintSpeed"

For me on this print it was "255°C = 8,5 * 30mm/s"

Any experience for good values with ABS?

Just thinking... Is it even linear? Maybe it would be an idea to do some tests with different parameters and do a "StringingIntensityMap" depending on Temperature and Speed

On the other hand: Isn't retraction exactly what shoud prevent this from happening? Or is it not additional material from the nozzle but some excess material already on the model that is building up the strings?

Cheers!

Edited July 12, 2016 by Guest

[RonanB 4]

Hi,

I think 30mm/sec travel speed is very slow (was it 300 mm/sec ?). You may try to increase it a lot. I almost print with 200 mm/sec travel speed, it reduce the print time a lot if the head have to travel a lot during the print and also I hear it helps with stringing.

If the head move slowly, the material have more time to flow with the gravity, increasing stinging. You can do some stuff with retractation (i don't use it very often so i don't know what is optimal for it).

I might be wrong, but you can give it a try on a smaller model.

Good luck !

[MarkHoe 3]

Hi Max,

Im pretty new in the world of 3D printing too, but as Sander replied, i would like to see the same model printed with printspeed at 30-50mm/sec. I believe thats is a good speed that allows the finish to still be nice.

Then set your travel speed to 100 or 150mm/sec. - The increase in travelspeed should not affect your printquality unless your printer is not on a good stabile underlayer.

The reason i like to see your print with this setting is, that i believe your stringing is because of the low travelspeed, which altso makes your printingtime much longer.

The increase in printspeed i believe to make no difference for the quality.

Can you mabye try it out and upload some Pictures of it for a comparaison?

[maxpartenfelder 5]

Hi Ronan,

thanks for the advice.

I have chosen the "scientific way" of doing it and will just try it out in a series of test prints.

Therefore, I designed a small test cone set, that I will print 12 times on the same bed in "one at a time" mode.

After every test object I will tune the parameters directly on the printer and evaluate the complete print afterwards.

Wish me good luck! I will post the results and the evaluation here afterwards.

Greets,

Max

[IRobertI 521]

Like others have already said, start by increasing travel speed. That alone will make a dramatic improvement I'm betting.

Edited July 12, 2016 by Guest

[SandervG 1,521]

So yes.. travel speed

Besides that; it is very difficult to capture all the data in a chart. It is submissive to so many values.. It is different for each brand, each color, and even by the size and complexity of your model. By doing more printing you will develop a feel for this and should be able to create quite some reliable results straight from the bat

Good luck with your test!

[maxpartenfelder 5]

Alright... I did my tests. Some of them worked out well, some of the not.

But I am really ashamed of myself...

When I unpacked my printer, it seems that I was so excited, that I messed up the ABS and the PLA rolls. Ever since I thought I was printing ABS, but acutally printed PLA @ 255°C.

This explains a lot.

Currently I am testing the printing with ABS at the right temperature and I am overwhelmed by the quality I am getting. It's like I got a compleatly new and better printer. Hahaha

Lessons learned: Always check fillament twice.

Thanks anyway for the kind support.

I might eventually redo the pillar test and post the results here (this time at the right temperature)

Until then, this might be some good link to take a look at:

https://ultimaker.com/en/community/2872-some-calibration-photographs

Cheers,

Max

Edited July 13, 2016 by Guest

[Shiren1981 0]

Well ABS allways has better detail then PLA becuase of the melting temp

and yes speed and temp makes a diff in your print i mostly print arround 25 mm/s

35 mm/s globale print speed and when i print pet-g on a temp of 205 or it starts bubbling

best thing 2 do is try finding the right settings and not only speed and temp but also extusion and retraction

[kmanstudios 1,120]

Also, do not forget that your environment can have a great effect on your print. For instance, I do not have a well controlled climate in my apartment and I can tell differences in materials when we get fast changes in temp and humidity.

Also, I find the default values in Cura for their machines to be great starting points.

As for getting rolls mixed up, yeah...welcome to the noobland!! It is how we learn. As Sander said, it is all about finding a feel for models and such. It is on of the things I like about it. It is as much science as it is art and techniques.