weird wiskers

CoreXY printer with .4 nozzle. E3D V6 on E3D Titan extruder 1.75mm

Layers are .15mm using white Petg

printer has been printing very well except for these weird hairs/wiskers/lines that appear every bunch of layers

file has 15% ifill

Using 1mm retraction
-.1mm restart
.1mm lift on retraction
60mm/sec retraction speed
0.5mm coast


any ideas?

Edited 2 time(s). Last edit at 11/22/2016 07:48PM by makerparts.

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Makerparts.ca
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retraction not enough, little ooze blobs catching as head moves to other part.

And PETG is really bad about oozing those over what you'd get with PLA or ABS.

I try to keep the temps low to keep the oozing under control.
I will increase the retraction to 1.5mm
i heard the retraction speed shouldnt be crazy fast.. so i will turn it down to 30mm/sec

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

Quote
makerparts
i heard the retraction speed shouldnt be crazy fast.. so i will turn it down to 30mm/sec

I wouldn't put too much stock in that as an absolute, everything depends on your particular setup. My advice is to try it faster.
The faster your retraction the less time your nozzle is stationary and oozing. As long as the filament isn't shredding. The same goes for travel velocity - if it can be increased without causing problems, then it spends less time oozing.

Looks like a skeleton?

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

Definitely ooze related. I'm not sure about that .1mm on restart, I'd remove that as well.

Try increasing travel speed to as high as you can reasonably make it.

It does seem to be printing these. They are consistently at about 40degrees.
These actually look repeatable if you compare the different parts.
Have you tried a preview of the code to check this isn't a problem in the model or the slicing.
With complex (curved) surfaces you can get model errors that are hard to identify.
If you looked at a single layer at just the printing you may miss it as it would just be a point in space.

There is no question that these are from ooze. This is a very classic example.

Here's how it does that:
- When the nozzle moves to one side or another the little bit of ooze on the tip gets deposited on the first thing it hits.
- At the start the ooze just deposits on the edge of the model close in, and makes a blob there.
- On the next layer it hits the bit of ooze from the previous layer first, so it slowly builds out at that angle, stair step!

BTW, you could also try a small bit of Z lift and see if that helps.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!

Thanks Paul.
Quite Fascinating.

Ive had the same issue on my printer before and it was retraction not working right because it was set too high and the motor was skipping.