Thursday, September 14, 2006


0.1mm Filament

I mentioned the idea of using lawn trimmer line to a coworker. He said a friend of his does a lot of jewelry crafts and they use extremely fine monofilament for some things. I poked around on the web a bit and found that it's possible to get 0.1mm (.004") nylon monofilament in large quantities relatively cheaply. I saw spools of 3000 yards going for $6. (Anyone care to work out the mass of that?) I wonder how practical it is to use nylon monofilament of that diameter. Wouldn't take a lot of heat to melt it, I would think. Not sure if it's practical to feed 0.1mm nylon, though.

I may have dropped a naught somewhere but that looks like about $280/kg to me. Pretty steep for nylon.

Also, nylon melts at pretty high temperatures, iirc.
Wouldn't take a lot of heat to melt it, I would think

Nylon melts at ~350 C. It may not take a lot of heat, but it will take a high temperature. (I'm not sure what the specific heat in nylon is -- better be low though, if we want it to cool fast enough after depositing it.)

Getting nylon in RepRap is a good thing, I think, for the strength, heat resistance, and low friction.

With nylon, there is another possible alternative to melt-extrusion. Just squirt separate .1mm misty jets of diamine and dicarboxilic acid -- these compounds react and form nylon. This would be an chemical reaction RepRap, rather than a thermo-RepRap.
//looks like about $280/kg to me. Pretty steep for nylon//

Hmm, not good. 3000 yards sounds like a lot but, at that diameter, it's nothing.

As for heating, you really just need a very hot point source. No extruding needed when the filament is already that thin. Really just need to melt it enough to stick to the previous layer. Or am I way off on this?
I got me some generic Weed-Eater trimmer line at the store today. I plan on testing friday with a hot-glue and soldering iron element to see if either will melt it effectively.

Most soldering irons operate around 200deg~c plus or minux 50, so I'd bet that will work fine.

Although I didn't see clear trimmer line where I went, there was red, green, blue, yellow, and black.
if trimmer line does end up working well as a substrate, then the different colors would actually be a benefit rather than a downside. you could choose your color based on what you wanted the object to look like =)
You are getting your Fs and Cs mixed up. Try 250F as a meling point.
You can break nylon line by rubbing it to heat it up.
Fishing line is basically what you have here but be careful because fishing lines are coated because nylon absorbs water.
oops I meant 350F.
Melting points range from about 200 C (350 F) to 350 C (650 F).

Depending on the specific kind of nylon, both my number, and your number is correct.
If one already has a filament of a thickness significantly less than the desired accuracy of the machine, could one not do away with extrusion altogether and simply lay it down flat on top of the previous layers and press it down with a heated, non-stick roller, kind of like spot welding? Better yet, one could use an ultrasonic plastic welder to stick the layers together, doing away with the problem of melting altogether. Of course, a fibre with a square cross section would be best for this, but you might get good results with round.

Conventional piezoelectric ultrasonics is of course way beyond most of our capabilities, but it might be possible with the more old fashioned technology of magnetostriction.
Yes not all nylon is equal.
I just did a little experiment.
My hot glue gun will melt into a plastic syringe (nylon I think) but won't melt weed-eater line or fishing line.
Using my hot air gun on low I can melt the latter two but not without the nylon becoming a mass of fine bubbles.
The syringe melt cleanly.
This doesn't bode well for nylon filement reprap unless to have to right type of nylon. Probably end up cheaper to buy the proper stuff in the first place. There might be a low melting point filament out there but beaders, fishermen and weedeaters will all want strong lines which I expect will not work for us.
from what it sounds, you were successful at melting trimmer filament. could you post a blog about that? i'd like to find out more details about that since it seems like a pretty ideal route =)
From the way I understand it - the accuracy will depend on the diameter of the extruder and the calibration of the extruder feeder to the diameter of the filament being used. You will need sufficient diameter of the feed material to be gripped by the feeder. I would imagine the extruder diameter should be less than the filament diameter.

So for a nylon monofilament the line should be 20/28 lb. test or greater to have a diameter of ~0.444mm to be larger than the standard extruder size. Perhaps there are some modifications that could be made to tighten the extruder feeder and find a smaller diameter extruder head. Then I think there will have to be a modification to the software (settings or code??) to allow for adjustment of diameter.

I think the purchase of fishing line for 3D printing may be expensive if buying the line new since it is marketed towards a particular industry. But there's tons of it that need to be recovered and recycled. There may be properties of the material that may be favorable for 3D printed models.

The great news I gather here is that melting temp. is around 200deg Celcius - which my extruder does reach. Not sure if it reaches 350 C?

Let me know how the other experiments work out and feedback on the comments above for collaboration. I am new to the 3D printing game.

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