Incorporating Natural Fibers

1a) Typically we use virgin plastic and blend the additives.  The current additives, for the most part, have been colorant.  My guess is that you would do the same with chopped flax fibers.  I don't know how you will chop the fibers up.

1b) Make sure the flax fibers are not waxy, so the molten PLA will bind to them.  You may have to pelletize and re-extrude afterwards.

1c) No, it really needs to be in pellets.  Look up "masterbatch", then up the ratio and apply it to what you are doing.

1d) Note that if you want to make this appeal to a wide audience, you need to be able to extrude comfortably through a 0.35mm printing nozzle.  This means you need to use the 200 micron screen extruder nozzle on your filastruder and still retain your material properties.

You can just dust the PLA pellets with the flour or fibers then pour them in the hopper.  The first pass or two will likely have poor distribution and require pelletizing and re-extruding.

I have seen posts of carbon fiber being added to PLA but has anyone tried it with ABS?. What about adding fiberglass to ABS, is it even possible?

I see I see. The fibers I am using have a particle size similar to flour, in the microns.

There was a fellow in California called JD Ledderman and within the past 3 years or so he 3D printed a plastic bottle made from abs and fiber plastic pellets. Nobody knows how he did this. Unfortunately he wasn't able to bring the product to market seeing it was "too biodegradable" for the food/beverage sector. Not enough shelf life. No one has heard from him in a bit. I tried to contact him but to no avail. 

There are only a couple people in the world that even make fiber plastic pellets and they don't want to sell you samples unless you buy a ton, sign and nda and basically disclose what you are doing with them. If I can't get some i'll have to make them and there will a lot of trial and error involved...but it is worth it.

Because! There is this big secrecy and almost  conspiracy about bio-polymers. In the early 30's, a man called Wallace Carothers was credited with the invention of Nylon, but not many know he was working on a bio-polymer on the side. This was validated by a man called Jack Herer. Apparently Wallace was able to make one successfully, but because DuPont owned shares in petroleum companies, they shut down his idea, which ironically could have lead to a much greener world today. He was able to make a fiber plastic without ANY petroleum based additives/plastics.

It can be done and that is my goal. The future is green. Petroleum needs to get phased out. Even if I have to start with like a 80/20 ratio (which I will have to from what people have told me) and work my way up, I will do everything I can to make this happen. Some people have even said that you need to soak your flour-sized fibers in a solution for 24-72 hours and dry it before running it through the hopper of the extruder. But maybe at the end of the day IF I succeed, perhaps it will be a product that will not be viable for 3D printing (but for injection molding instead or other plastic composite uses). It's worth a try, I think, and I have the time to experiment.

Sources to prove I am not full of **** :

Encyclopedia of Textiles, 3rd Edition by the editors of American Fabrics and Fashions Magazine, William C. Legal, Publisher Prentice-Hall, Inc., Englewood Cliffs, NJ, 1980; The Emergence of Industrial America Strategic Factors in American Economic Growth Since 1870, Peter George State University, NY; DuPont (a corporate autobiography published periodically by E.I. DuPont De Nemours and Co., Inc., Wilmington, DE.; The Blasting Handbook, E.I. DuPont De Nemours & Co., Inc., Wilmington, DE; Mechanical Engineering Magazine, Feb. 1938; Popular Mechanics, Feb 1938; Journal of Applied Polymer Science, Vol. 47, 1984; Polyamides, the Chemistry of Long Molecules (author unknown); U.S. Patent #2,071,250 (Feb. 16, 1937), W.H. Carothers; DuPont Dynasties, Jerry Colby; The American Peoples Encyclopedia, the Sponsor Press, Chicago, 1953.