1

Topic: Filament coming out grey

Hi folks,

Having a problem where the filament is coming out grey.

I took the entire thing apart and soaked the pipe in acetone, everything is completely clean, just installed a melt filter also.

Pellets are:
http://store.os3dp.com/kumho-750sw-abs- … 750sw.html

But was having the same issue with PA747.

Temp is 180C.

Any ideas?

Thanks!

2

Re: Filament coming out grey

Last time I ran the Kumho, I ran it at 192c.  Not sure if upping the temp will get rid of the grey but may be worth a try.  Does it stay grey or does it get lighter the longer you extrude?

-os3dp

3

Re: Filament coming out grey

I ran it for about 30 min and it produced maybe a foot of filament, all grey.

At that point I realized that something was wrong with it, so I shut it off.

4

Re: Filament coming out grey

This is very strange. I made a detailed review of 750SW here and had no problems other than a slight decrease in speed, but still much faster than PA747. Are you running vertical, horizontal, or angled?

Have you lubricated your thrust bearing lately?
What was the last color you ran? Have you extruded black any time recently?
What type of colorant do you use; masterbatch or powder?

Some colorants stain more than others, especially Blue powder-based colorant. Black can take up to 500g to purge it all. I understand you soaked everything in acetone, but with powder colorants (as an example), it needs a little elbow grease to really get it clean without sacrificing virgin pellets. it also sounds like you have two things going on here. Anytime I lose speed, I check the thrust bearing and tweak the SPB as needed. If you have a damaged/under-lubricated thrust bearing, you will drop production speed more and more as time goes. Here's a report I made one year ago http://www.soliforum.com/topic/15622/wh … ugh-today/

Also, as OS3DP mentioned, raise your temps to 192c and go from there.

Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!

5

Re: Filament coming out grey

So I tested with some extra PA747, and it still comes out grey.

The pellets are fine, it's the extruder that is having issues.

I lubriated the thrust bearing the last time I took it apart.

I have only ever done white pellets, no colors at all, ever.

I think my filastruder is defective, I do have an earlier model.

I have basically been having this issue off and on since I got it, people have told me to clean it, but still having this issue even after cleaning.

Running it perfectly vertical.

Pretty unhappy with the product, I have had it for about 3.5 years and have only produced 30 kg at the most due to problems. Once I think I have solved them, the grey comes back.

6

Re: Filament coming out grey

Gray filament comes from a few things:

- Over temperature
- Over exposure to heat, typically from one or more of the following:
  - Blocked melt filter nozzle
  - Worn/dirty barrel/auger
  - Slow auger speed

I reviewed your posts, and noted a few things:

- It looks like in mid 2016 you posted saying you'd produced 40kg at that time. Is that right?
- It looks like at that time I recommended a replacement barrel/auger, did you try that? Just cleaning it won't help if the surface finish has been worn or damaged. It is possible for the barrel's internal finish to be worn/damaged fairly quickly if the parts are not aligned during assembly.

7

Re: Filament coming out grey

At that time I had estimated roughly 40kg, but I went back over my pellet purchases and I realized recently it was closer to 30kg.

I will be trying a new motor / new barrel / new augur.

Thank you!!