ABS Grades

I have noticed a difference in quality between black ABS and other colours. I don't know if anyone else has noticed a difference.

The black ABS does not extrude as smoothly. It seems a bit lumpier and the lines in the finished print show up a lot more.

I have tried a couple of suppliers but the latest filament I bought (1.75mm) came from America Instrument via Amazon in the UK. The red, yellow and green filament have been fine. It extrudes smoothly and the layers merge into each other. The black however is not as good.

I understand that a lot of ABS is now recycled (old car parts etc) and it ends up mixed with black pigment. This must make the consistency and quality very variable.

Do we have any experts on the ABS grades available or a maybe direct line into a manufacturer? Is it possible to buy virgin ABS that comes straight off the plant rather than mixed with recycled junk?

Dave,

It's very common in many plastics manufacturing to use 're-grind' or recycled material form leftover scrap or defective parts in the production of 'new' We do injection molding, and running up to 33% or so 're-grind' is OK for most parts as long as they are cosmetic and not critical tolerance or surface quality sensitive. Buying cheap filament from amazon or ANYwhere for that matter, pretty much guarantees you'll get bad black filament, as regrind usually can only end up as black. Most of the filament manufacturers in the US that I know of use virgin resins in all their colors, but overseas, and even some early manufactured US stuff had regrind in their black resins

John,
Thanks.
The filament I bought I don't think can be classed as cheap filament. It is sold as "Jet Filament" and made by America Instrument. It was made in the States and was over 30 GBP per spool. I bought it because I had heard good reports. As I said the other colours are OK.

I think to recycle it internally within a factory as re-grind is one thing; the process is under your control, but to buy it in from a recycling plant and mix it in is something else.

Edited 1 time(s). Last edit at 02/02/2014 06:23PM by dave3d.

I agree black filament never seems to give you the quality of natural or white. I always thought it was the coloration that was doing it but makes more sense that it's a higher percentage of scrap material re-grind

Edited 1 time(s). Last edit at 02/03/2014 01:08PM by cnc dick.

Yeah, I used to work at a very large injection molding company (for automotive stuff). They had specs saying that they could use "up to 10% regrind" in parts. Funny thing, I never saw 10% regrind, it was always either 0% or 100% regrind.

What's worse is that it is nearly impossible to tell most black plastic from any other type of black plastic, once it has been reground. Black PET, looks like Black PC, or Black ABS, or Black ASA, or Black PC/PBT, or Black HIPs. And there are a LOT of incompatible plastics like mixing Polypropylene with ABS. Even when they meant well, the would still combine incompatible resins and produce junk. With filament, it is really hard to tell, without running the filament through a printer. All ABS's aren't even compatible with each other. You can't extrude a high melt flow injection molding ABS into filament without a very wide tolerance.

Even worse than these is that bad extruders will pass off anything that will run through the extruder as good stuff. Black is the color that catches ALL of the garbage. The might be throwing in floor sweepings to boot. They get to figuring that they are "recycling" and they are just producing junk, but selling it at premium prices.

Its weird but black abs always comes out really nicely on my machine. I do print with a .65 nozzle though.

@aduy, it really depends on where you get it.

In a perfect world, most filament suppliers would use natural ABS with the correct black colorant to make good quality black filament. They could then use the purgings, recycled ABS, or junk plastic to make the spools. Most extruders don't have their own injection molding machines (not to mention how many tens of thousands of spools it would take to justify a mold / molding machinine for spools). In reality, a lot of the worst extruders will push just about anything into filament if they are sure they won't get caught. Unethical - absolutely, but it happens. It's been that way for open markets from the beginning. In latin class, we learned the phrase "Caveat emptor" - "Let the buyer beware". Which means they had bad supplier problems even 2000+ years ago.

If you get a chance to read Richrap's blog about some of his trials, don't forget his nozzle jams post. Instead of just bad colorant, or bad plastic, they were loading the PLA with ball bearings. It's about as bad a product as you can get. In another post, he had some black plastic that exploded in his trash can.

Weird & poor processing with a lot of different suppliers of filament is why most people with 3d printers avoid most Chinese suppliers.

If you found a good supplier of filament and you like them, by all means, stick with them. If you feel adventurous and try lots of different suppliers form many different places, you will find what we are talking about.