1 Topic by jmccabe871

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Topic: Clear PETG Coming out with a grey tint

Hello Soliforum,

Long time reader first time posted here. I have an issue with PETG filament extrusion and i was wondering if
anyone here might be able to help. I am trying to extrude Eastar™ Copolyester 6763 into filament for 3d printing however
when i do so at about 180C it comes out with just an ever so slight grey tint and this comes thru on the prints. I have tryed to run it hotter and that seams to help a bit but at that point the draw down is to much and the filament comes out way to thin to use I also use a filawinder and at the higher processing temp the filament likes to slump and wad up. So my question here is, what should i try to do next to make this work better and is there something wrong with my process? BTW: I did dry the pellets and I also torched and cleaned out the filastruder die and barrel before I ran it on the clear.

Thanks in advanced for the help!

P.S 
If off hand anyone responding to this also runs PETG Filament and you point me in the way of some compatible colorant smile.

"If the screws ain't turnin, we ain't earnin!" - Co worker from day job
-James McCabe
General / Technical Manager
McCabe Part & Prototype , LLC

2 Reply by IanJohnson

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Re: Clear PETG Coming out with a grey tint

Maybe lower the temp a little? ABS will discolor when overheated, but I don't know if the cause of that would apply to PETG.

3 Reply by jmccabe871

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Re: Clear PETG Coming out with a grey tint

I will give that a shot, however I dont know how much colder I can go until the material will not be able to push out.

"If the screws ain't turnin, we ain't earnin!" - Co worker from day job
-James McCabe
General / Technical Manager
McCabe Part & Prototype , LLC

4 Reply by elmoret

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Re: Clear PETG Coming out with a grey tint

How much PETG have you run so far? It might be contaminants on the inside of the barrel that need to purge out over time. Without colorant, any impurities show up easily.

Also photos would be helpful.

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5 Reply by jmccabe871 (edited by jmccabe871 2016-12-05 02:20:44)

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Re: Clear PETG Coming out with a grey tint

Since am last clean out I have ran about half a kilo on it and it came out like this

http://imgur.com/HWhBtVo

Here is a picture of some I ran hot about 2 months ago (the spool was made with inland)

http://imgur.com/iHWXVGE

Here is colder (180C ish) run from two months ago

http://imgur.com/Jvh2n7Q

and here is the resulting print from that lot of materal

http://imgur.com/IjT5c0d

I will be starting back up in about an hour and I will try running at a lower temp.

Thanks for taking a look at this for me.

"If the screws ain't turnin, we ain't earnin!" - Co worker from day job
-James McCabe
General / Technical Manager
McCabe Part & Prototype , LLC

6 Reply by elmoret

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Re: Clear PETG Coming out with a grey tint

Looks like a lot of bubbles in that one spool, are you drying the pellets?

Here's someone using colorant with 6763:

http://www.soliforum.com/topic/15657/co … -colorant/

Filastruder - the robust, inexpensive filament extruder
E3Dv6 All Metal Hotend - the premier 3D printing hotend

7 Reply by jmccabe871

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Re: Clear PETG Coming out with a grey tint

I did not dry it much that time, this time I am drying it for about 3 hours at 160F in a prtintdry. I am about to try running it with a 2MM Nozzle to see if i can run hotter and compensate for draw down it looks like genesat1 did something kinda like I am about to try. Also Now I have a place to get color for this stuff big_smile .

I will try it and let you know if it helped.

Thanks again for your time.

"If the screws ain't turnin, we ain't earnin!" - Co worker from day job
-James McCabe
General / Technical Manager
McCabe Part & Prototype , LLC

8 Reply by jmccabe871

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Re: Clear PETG Coming out with a grey tint

I am up and running right now on the 2MM Nozzle and at 210C That Gives me about 1.78 on the winder which if i can hold it will work well. It still looks to have a grey tint but the other forum post did not look too different from that, I guess I will just have to color the material, Not a huge deal. One thing of note was a bit of black specs in the feed though on the filastruder I blew that out and I have no idea where that came from at all?



Thanks for all the help!

"If the screws ain't turnin, we ain't earnin!" - Co worker from day job
-James McCabe
General / Technical Manager
McCabe Part & Prototype , LLC

9 Reply by BurningRingOfFire

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Re: Clear PETG Coming out with a grey tint

Was the material run-of-mill (virgin) purchased new sealed in mill-bags?

Or did you buy it second-hand from ebay or another source?

Usually people liquidate material because it has problems,   we used to sell overheated nylon by the gaylord-box to another molding plant.   They'd dye it black and use it in lower-tier products.   It could have a grey tinge to it that you don't see until you extrude it.

Or there could be something off-spec about it,  maybe a manufacturing defect that causes it to extrude gray.

Black specs are usually burnt material flaking off or the finish of the screw/barrel flaking.   

Here's a pro-tip from the big shops:   Make sure you polish your screw and barrel as smooth as possible.    The microscopic scratches and pits from scouring and cleaning can actually make clear material that much worse.   It doesn't take much to degrade (burn) polymers,  and those little black flecks will show up real good in light colors and clear.

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