What is causing this "hair" to appear on prints?  

RE: What is causing this "hair" to appear on prints?

I think your first layer is to high.

the picture I can not zoom in, make a new picture of your first layer only, then we can look if this is good, after that you should have I hope less problems.

You give the temps, but not what filament?

Most important for 3d printing, is 1. clean bed(wash with dish soap), and 2. first layer 100% good.

How I work:

A new sheet will stick less then a used one.

PLA sticks more difficult on a powder coated sheet. Is still possible settings need to be more preciese.

This how I work on a pei sheet(there are always exceptions):
Most important to 3d printing is:

1. 3d print will never be like start and i have the print, there will always be problems!!!!!!

2. A clean sheet, use dish soap, then you can print on it. A few prints you can use alcohol, then again dish soap,
big flat models and models with small footprint on sheet- use glue stick(and not every glue stick is the same,
use one that makes a thin layer), and big flat models and small footprint, use a big brim attach to model so footprint is bigger.

Petg sticks to much on the pei sheet, use window cleaner, this leaves a layer on the bed, so it does not stick to much.

3. To get it stick very good, a 100% first layer is very important, see youtube for movie on this.
Every new print watch the first layer, and look if it is 100%, this will also prevent a big ball of filament on your nozzle wen model let loose during printing.

Extra: (normally not needed).

First layer, print hotter.
First layer slower.
Bed more heat.

Most problems are first layer to get this 100%, and bed not clean.

Bad filament is possible, or filament with water inside.

Move extruder to the top and extrude filament, it should go straight down(if not, nozzle possible blocked),
it should be thick enough(if not, nozzle possible blocked, or partial blocked), (do a cold pull),
if Bubbling during extrusion then it has to much water inside.
Check after the first layer is ready, then you see if it sticking enough, and not releasing and sticking to the nozzle.
If you see white spots like a bubble on the bed, then filament is releasing from bed.
Also no gabs between lines should be visible.

Use 7x7 calibration for first layer, see settings in the printer.
Search for " 3D printer first layer problem Calibration process" on youtube, movie on first layer calibration, with a good zoom in.

RE: What is causing this "hair" to appear on prints?

@peter-m26

Here are some close up 1st layer pics. I did lower it a bit for this. I'm using Prusament PETG. Surface is cleaned and Windex applied.

RE: What is causing this "hair" to appear on prints?

So this starts many layers in. You can see the previous layer was just fine and then all of a sudden this hair-like layer starts.

I'm going to re-slice it.

RE: What is causing this "hair" to appear on prints?

A different infill pattern is better but same problem. Any thoughts?

RE: What is causing this "hair" to appear on prints?

Speed and temperature is possible.

Try a temp tower to get the best temperature.

Try a slower speed.

RE: What is causing this "hair" to appear on prints?

Thanks for the temp tower suggestion. That made the difference.

RE: What is causing this "hair" to appear on prints?

Could also be over extrusion, measure the filament thickness.