1 Topic by malek1979m (edited by malek1979m 2014-02-02 16:46:54)

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Topic: Filastruder / FilaWinder black segment and stretch marks

I'm filastruding and filawinding nicely and consistently now, but I did notice a couple things that were troubling me. One thing is that about half way through filastruding and filawinding 2 lbs of white ABS, I noticed a segment (several feet) of filament was actually not white, like it was very dark, as if burned (see picture, right in the middle of the spool, although it's hard to see, but it's that area that is a bit darker. It may look like a shadow, and a little bit of it is, but it's mostly just dark). Let me tell you that I have not yet put a shred of any colourant in the filastruder. I have only used white so far. Any idea what could cause that? I'm extruding 3mm ABS filament (actual: 2.85mm) at 192.5 c, vertically.

The other issue I'm having is the apparent stretch marks on the filament after it is wound (right after it comes out of the PTFE tube). This probably doesn't happen with 1.75mm filament, but 3mm is very stiff and as soon as it starts bending a little, you can see stretch marks on the entire thing. How come filament you purchase doesn't look like that? I have a feeling that one way to fix this would be to slightly heat up the filament immediately prior to spooling it to a specific temperature that won't change the filament consistency but will be just enough to soften it for easy spooling. Do you think this would work? I had this crazy idea to try to point a halogen light (see picture) at the spool just far enough to soften the filament. I've actually been using a halogen light just like this one in certain cases to heat up ABS/PLA parts after printing them so I can mold them a little if they don't come out perfect. Like if a part warps, I've actually been able to unwarp it using this method. Any ideas?

https://dl.dropboxusercontent.com/u/60513393/IMG_20140202_114530.jpg
https://dl.dropboxusercontent.com/u/60513393/halogen%20light.jpg

2 Reply by elmoret

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Re: Filastruder / FilaWinder black segment and stretch marks

Not sure what would have caused the dark segment, but since you aren't putting any colorant in it wouldn't take much to color it. If you want truly white, you need to add white colorant. Natural ABS does not contain colorant.

Stretch marks shouldn't be a problem after printing. I've never seen that before with 1.75mm filament, can you use a larger ID spool?

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

3 Reply by malek1979m

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Re: Filastruder / FilaWinder black segment and stretch marks

But is this actually natural filament? I thought natural pellets/filament would have been transparent, yet my prints, even if they are single walled, are far from transparent. I don't think I've seen white colourant on any site...
And using a larger ID spool would not work because the stretch marks are created right after coming out of the PTFE tube, and it's as big a diameter as it gets. Hm... I wonder what would happen if I used another PTFE tube with a much larger diameter... Why is it so small anyways? It's a lot smaller than the 1.75mm PTFE that comes with the kit.

4 Reply by elmoret

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Re: Filastruder / FilaWinder black segment and stretch marks

Natural ABS is most definitely not transparent. Here's some white colorant.

http://www.indhobbies.com/Masterbatch_Colorant.html

Filastruder - the robust, inexpensive filament extruder
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5 Reply by IanJohnson

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Re: Filastruder / FilaWinder black segment and stretch marks

I've seen natural ABS come out pretty gray when it gets overheated around +200C.   Maybe at 192 some of it got hot enough at some point to catch just a shade of it.  That's nozzle temperature, I don't know how hot it gets in the melt zone to cause that.   You might try sliding the heater band a little closer to the nozzle so it doesn't have to get as hot to give you 192 at the opening.

I have another batch of the 6mm PTFE on the way, I'll send you a longer length of it when it comes in.

6 Reply by malek1979m

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Re: Filastruder / FilaWinder black segment and stretch marks

That makes sense. I'll try that.
And thank you in advance for the PTFE, I appreciate it. But will a longer piece make a difference to the final product?

I looked at my nozzle tip and saw this:

https://dl.dropboxusercontent.com/u/60513393/IMG_20140202_131855.jpg

Talk about ew! Why is this happening? I have a feeling it has something to do with the gray-ish filament.

7 Reply by IanJohnson

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Re: Filastruder / FilaWinder black segment and stretch marks

Were you running PLA before switching to ABS?  Looks like not all of the PLA was purged.  When I switched from ABS to PLA once I found that I kept getting bits of ABS in the PLA, which was easy to see since the PLA was clear.  I found that if it ran hotter, the PLA seemed to slide past the leftover ABS, but if it was cooler the increased viscosity would start to drag the ABS out. 

It may be true the other way around.  If you need to purge PLA try running the ABS at a lower temp for awhile so the extra friction can scour the sides of the barrel.

8 Reply by CraigRK (edited by CraigRK 2014-02-02 19:31:03)

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Re: Filastruder / FilaWinder black segment and stretch marks

malek1979m wrote:

But is this actually natural filament? I thought natural pellets/filament would have been transparent, yet my prints, even if they are single walled, are far from transparent.

The first ABS filament I bought (and am still using) is natural, and it definitely is NOT transparent.  The same for the ABS pellets I have.

malek1979m wrote:

I don't think I've seen white colourant on any site...

I think most don't stock it as they assume people are happy to settle for the offwhite that Natural gives.

I stock white masterbatch (See Tim's "Polymer Suppliers" sticky) as I thought it would be useful if people wanted to the make things like pinks, etc.  In other words, white is very much available and neededif you want to make white filament.

Masterbatch, ABS and PLA Pellets available for UK and Europe.
http://www.emakershop.com/Seller=1324

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9 Reply by malek1979m

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Re: Filastruder / FilaWinder black segment and stretch marks

Thanks CraigRK.

Ian, I did have PLA in there at one point in the past when I first attempted to extrude PLA without dehydrating it and failed miserably. That was a couple weeks ago. I did take apart all the parts the pellets/filament pass through and cleaned them thoroughly, but maybe there were some pieces left over. However, this IS the first time I try to extrude at this temperature (192.5c). The last 2lb spool I made was extruded at 185c. So perhaps the temperature change did have something to do with it. I'll try your suggestion of lowering the temperature temporarily to purge out the PLA and then I think I'll stick to 185c for my next spool, but without a fan.