Stringy PETG prints

3D Printing 3D Printers
,
1

Hey everyone,

So I’ve decided to try printing PETG on my Wanhao duplicator i3 since i want to print higher temperature materials but not have the thermal challenges of ABS. I am able to print some decent looking parts but not without them having these strings around the print (see photo of 20mm cube). The strings only appear to be on the edges and the base and top of the print seem to be fine. I’m using these cura settings below and the PETG I’m using is Inland PETG, any recommendations on how to mitigate this issue?

print speed: 45mm/s

temp: 235C

bed temp:90C

retraction speed: 40mm/s

retraction distance: 8mm

Outer shell and top/bottom speed at 20mm/s

IMG_20161009_164204.jpg
IMG_20161009_164204.jpg4160×3120 3.07 MB

3 Likes
2

Adding second photo to show another view of the print.

IMG_20161009_164219.jpg
IMG_20161009_164219.jpg4160×3120 3.02 MB

1 Like
3

Hi

Maybe this does not apply to your situation, but In CURA I’ve been running everything using Perimeters before infill.

I see from time to time depending on print and material, that I get Zits sometimes on the outside of some of my prints.

I think what is happening and have yet to really confirm it, is that at certain times, when infill stops to move over, I think that

the extruder is turning off the filament feed, but it takes a short time to stop and change direction.

If, in your case infill is running before perimeters, it could possibly be that the filament is turned off and the extruder travels a bit, which

I think could be leaving strings.

I do not have a Wanhao printer, so I may be very wrong in your situation, But that’s my two cents worth.

I hope it helps you in some manner.

2 Likes
4

Hey there,

The cube is hollow, there is no infill so I don’t think it’s the issue. thanks for the input however.

1 Like
5

Did you tune the filament diameter and extrusion multiplier? Try setting all speeds the same except travel. So if you are printing at 20 set all print speeds to 20.

6

I don’t know if my input is worth anything to you as I’m using a different printer & filament size, but I’ve had great luck with PETG. I’m using a Lulzbot Mini with eSUN PETG 3.00mm filament and get great results with no strings at all. Low & slow seems to work for me. Here are some of the settings from a Cura profile I’ve saved that work great. You can translate these to whatever slicer you’re using…maybe try to at least replicate these, see if it improves your results then tweak from there. Mine has a .5mm nozzle.

layer_height = .38
wall_thickness = 1.0
retraction_enable = True
solid_layer_thickness = 1.14
fill_density = 20
perimeter_before_infill = True
nozzle_size = 0.5
print_speed = 30
print_temperature = 220
print_bed_temperature = 65
filament_diameter = 3.00
retraction_speed = 10
retraction_amount = 1
retraction_hop = 0.1
travel_speed = 175
bottom_layer_speed = 8