first few yards of PETG  

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dce
 dce
(@dce)
New Member

Hi

I am new to PETG so I purchased several different brands to evaluate CURA settings, etc. 

I tried many settings on the first role of filament with horrible results.  No matter what settings I used I got poor adhesion, stringing, globs, gaps, etc.

But after the first few yards of failed filament, the prints began to come out beautifully.  I tweaked the settings looking for the range of when the prints would begin to fail again, and found it to be difficult to get it to print poorly.  The opposite of how the first few yards performed.

Having nailed down a good range of settings with the first brand of filament, I tied a different brand with settings at about the middle of the range used for successfully printing with the previous brand.  Again every print was terrible, regardless of how I adjusted the setting.

However, again after the first few yards of filament failed to print properly, all prints began to print beautiful.  The range of good settings was now almost identical to the first brand of filament.

Is it common  that the first few yards of a new role of PETG are "stale", causing poor quality prints, and you have to get down to the "fresh" filament before you can get good results?

Any Advice would be appreciated,

DCE

Posted : 04/02/2020 4:14 pm
vintagepc
(@vintagepc)
Noble Member

I suspect the problem is dirty filament. You are likely handling the first few feet when loading and so it is getting contaminated with hand oils or any hand creams/products you use. Depending on their makeup you're going to get all kinds of problematic effects that don't go away until the residue makes its way out of the hot end.

Get some cheap disposable gloves (nitrile, non-powdered) from your local pharmacy and always wear them when handling filament, see if your problem goes away. It may also not be you, could be the worker that packed the filament in the factory. But that should not be an issue with more reputable brands of filament - or at least a rarity on the odd roll. 

Additionally, wipe off the first bit of filament with some IPA on a paper towel (while wearing gloves). May not get everything, but might remove enough that you no longer have issues.

This post was modified 4 months ago by vintagepc
Posted : 04/02/2020 4:26 pm
dce
 dce
(@dce)
New Member

@vintagepc

Thanx,

Ill give it a shot,

DCE

Posted : 04/02/2020 5:30 pm
bobstro
(@bobstro)
Famed Member
Posted by: @dce

[...] Is it common  that the first few yards of a new role of PETG are "stale", causing poor quality prints, and you have to get down to the "fresh" filament before you can get good results?

This one's going to be open for debate, but I've been following discussions over the last year on the impact of moisture -- notably relative humidity -- on different filaments. PETG is known for being impacted by the effects of moisture, whether it be simple RH or actual absorption by the filament. One interesting article noted that spool design will have a significant impact, with open spool designs being more subject to absorption but also faster to dry. If you've left your spools open for some time, that might explain your "bad first few meters" if those correspond to the coils on the spool most exposed, particularly if the spool sides are closed.

You might try drying the spool next time this happens. Also store them in zip-loc type freezer bags with a packet of fresh desiccant if you're not already doing so.

 

This post was modified 4 months ago by bobstro
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 04/02/2020 5:36 pm
dce
 dce
(@dce)
New Member

Interesting point.

In my case both spools were used immediately upon opening, but i do recall it being stormy on the days that I had issue.

I was honestly suspecting the opposite end of the spectrum, since both spools came in clear plastic wraps, I that considered drying out or UV damage from prolonged exposure to sunlight might be a factor.

I never thought of moisture, but it does make perfect sense, 

DCE

 

Posted : 04/02/2020 8:34 pm
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