Polyamide

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A polyamide is a polymer containing monomers of amides joined by peptide bonds. They can occur both naturally and artificially, examples being proteins, such as wool and silk, and can be made artificially through step-growth polymerization or solid-phase synthesis, examples being nylons, aramids, and sodium poly(aspartate). Polyamides are commonly used in textiles, automotives, carpet and sportswear due to their extreme durability and strength. -- Wikipedia.

In our case the Aliphatic polyamides-family, hence the somewhat sloppy but memory friendly and enlightening than just Nylons.

Contents

Caution

Just as with any other thermoplastics (such as ABS) used in a FDM-3D printer context, please make sure you have adequate ventilation in your workspace and/or the knowledge to go with it.

A little knowledge is a dangerous thing. So is a lot, but then again you know and hopefully realize what you are doing, if not for your own sake, at least for (y)our surroundings. Further more; exhilarating and guideing your fellow man/machines adequately, goes along way down the road compared to an alternative such as deterrence rhetorics. Oh, and use the source Luke, but check what you use and refer to. I mean, anyone can write an wiki-article and sound like they know something.. oh wait..

Article over at Instructables outlying the safety risks of printing with materials such as: ABS, pure Nylon, and trimmer line.

Overview

Advantages of Nylon:

1. It is very cheap, at less than half the price of conventional filaments. This is because the plastic is readily available as weed wacker line.

2. It is readily available. Hardware stores everywhere sell weed trimmer line in many different sizes and colors. See below for a list of Internet sources.

3. Prints are flexible and wear resistant. Unlike ABS and PLA, Nylon is far less brittle, and therefore stronger. It also has self lubricating properties which are useful for printing gears etc.


Disadvantages of Nylon:

1. It is more stringy than ABS or PLA. Overfilling the part will make a gooey mess with strings everywhere.

2. It warps more than ABS or PLA. This is why printing on cardboard is necessary to prevent warping.

3. It requires more clean up due to having to print on cardboard. More details are below.

4. You must dry Nylon before printing (see below)

Instructions

Steps for printing Nylon:

1. Get 0.105 inch trimmer line. This will work with a 3mm extruder. Make sure it is Nylon. I got mine on amazon here.

2. Dry the filament by putting it in an oven at 300 F(~148.88°C) for 3-4 hours. Don't dry all of it at once especially if you live in a humid climate. I dry enough to last a week. If you do not dry it, the extruded material will get all foamy and make your parts very bad looking. This is due to the evaporating steam. It will also overfill the parts because of the bubbles in the filament. This will cause your part to look stringy and blobby.

Additional resource regarding drying Nylon: October 1999 issue of Plastics Auxiliaries.


3. Put the dried filament in a ziplock bag, and put some desiccant with it to keep it dry. I used some "closet desiccant" I got from Walmart, with the ziplocks that have a slide thing.

4. Feed the filament out of the bag and into your extruder.

5. As seen in the video, make a bunch of little clamps to go around the outside of your bed. I just used some pieces of wood with holes in them and some small bolts that go through the table. You could also print something that would probably work better.

6. Cut a piece of cardboard to size, so that it fits under all of the clamps. Slide the cardboard in and screw the clamps down. You can use pieces or cardboard multiple times, and on both sides.

7. Go to http://forums.reprap.org/read.php?1,70471,page=3 for the slic3r settings (config.ini). You will need to get your heated bed up to 120°C and your nozzle up to 245°C. The given printer settings are not going to work for everyone, so experiment.

8. Calibrate the height you want to print at. The closer to the cardboard you are printing, the more adhesion, but the more cardboard you will need to get off of the bottom when the print is done. It will also make you use cardboard faster. On the other hand, if you don't care what the parts look like, it doesn't matter.

9. Start printing :)

10. Optional: Use a rotarytool(dremel) with a fine wire brush attachment to take off the cardboard stuck to the bottom. The wire brush should take off the cardboard quite easily, but not damage the Nylon.

   Option 2: Get some drain cleaner from the store. 
Make sure it is the stuff with Sodium Hydroxide and not Sulfuric Acid.
Use rubber gloves, and add a small amount of water to a container, then pour in some drain cleaner.
You only need to have enough to cover the bottom of the part.
Put the part in the solution, again using gloves.
Let it sit for about 15 minutes, then take it out and rinse it off.
Use a wire brush to brush off the wet cardboard.
You can use the above option to clean it further.

Videos

The newest video is without cleaning the cardboard off as in the instructions above.


Newest Video:

Older video:

Sources of filament

Check the Printing Material Suppliers-list with user reviews and report your findings.

http://www.amazon.com/dp/B001BKZT1S/ref=pe_175190_21431760_M2T1_SC_dp_1

http://www.amazon.com/Weed-Eater-952711559-0-080-Inch-2000-Foot/dp/B0010XRBXA/ref=sr_1_2?ie=UTF8&qid=1295391377&sr=8-2

Further reading