PETG with blobs

[Eber]

Hi there,

first of all, sorry for my bad english
I have some problems with PETG (white), in particular about blobs at the end of the perimeter and in the points of retraction, with my I3 Pro B bought in November 2018. In this period of quarantine i dusted it, and i made some test with different filaments.

With PLA is all ok; calibrations are ok.

My retraction values, with S3D, are:

Marlin 1.0.04
Nozzle 0.4
original Hotend
Print speed 60 mm/sec
Accel x/y 4000
Jerk x/y 20
Jerk E 10

3,4 mm distance
12 mm/sec speed
coast 2 mm
moves speed (out of the print) 140 mm/sec

I tried with nozzle wipe, with higher distance and speed, but no changes...I haven't stringing, only blobs , in the classical stringing tests and in some real cases with frquently moves form one point to other in the air (and relative restart the print).
And in the temperature 225-245.
I noticed that when nozzle comes in point (or moves from the end of a perimeter to the start external permeter) it stops for a "x" thents of seconds, and that is sufficient for a little blob.

There are other solutions? It can be a problem of hotend (i repeat, with PLA is almost perfect)?
Is there any profile from wich can i start?

thanks in advance

[William]

Hi, can you provide some pictures or videos?

[Eber]

Hi,

i wanted to take them yesterday, but when i started the first print of the day, i've got a bitter surprise, that can you see in video.
I don't know why, i didn't touch nothing from the last print; the same issue with PETG and PLA. Until the day before, it was all ok (a part of PETG blobs, but unless PLA and the quality print in general was ok).
If you have an advice that can be explain in a few post, in other cases i will start with other Topic, for that problem.
The bed level was ok, but effectively the lines of the first layer seem to be a little bit big and distant from each other.

This is with PLA:
https://photos.app.goo.gl/fis9GU2QS7gacnY6A

With PETG:
https://photos.app.goo.gl/ZyhFcHLvtVapGDXG8

In the follow, it starts ok and then crashes:
https://photos.app.goo.gl/z9hDRFoVH9To3roLA

[William]

Hi，PETG usually prints better with a higher nozzle to bed distance to avoid the nozzle picking up filament that might drip on your print later during the print. Also, the extra distance helps prevent excessive adhesion issues that for example might occur when printing on glass or PEI beds.

There are two other possible reasons:
1. The head temperature of the printed model is set too high.
2. The heat dissipation of the model is not enough

deal with:
1. Reduce model heat dissipation.
2. Add a fan to directly blow the model
Hope to help you.

[Eber]

Ok,

i partially solved...i will try other prints..Thankyou so much

[William]