Hi Group,

This may be the dumbest question posted here, but I am darn curious. First of all, I am not a materiologist, as you will soon discover (if not already). Hence, I know nothing about polymers, plastics, etc.

However, I find it quite convenient if we could use trimmer line as the material to plastrude, considering it comes in rolls already and it is virtually available all year long, everywhere!

I did a first try with the material that I had in hand and of course it did not work. So I am guessing most trimmer line materials will not work. I think they are not thermo plastics.

But is there a trimmer line out there that may be in fact be made out of one of the plastics that we want to use on our machines? Has anybody considered this as an option or is it already known that it will not work?

Thanks for your input!

JIQ

You can check if its a thermoplastic, just warm it through a candle and pull it whilst its warm. Dont burn it just soften it.

Its a thermoplastic if it stretches nicely and when cool has the same properties as before, ie its flexible and looks the same. This can be used for rapid prototyping.

Its a thermosetting if when you heat it it either doesn't stretch, just burns, or after cooling it looks different and has different properties, ie its black, brittle
etc. This is clearly no good for rapid prototyping.

My guess would be its a thermoplastic, possibly Nylon, as it is unusual to extrude thermosetting plastic, its usually used for injection moulding.

The main problem you have will be feeding it through your extruder. It has to be pushed through the extruder usually by a pinch wheel or worm drive, so must be of a generous diameter and fairly hard to have rigidity. Most repraps work on 2.8 to 3mm wire. Any smaller diameter will kink when in use. If you could solve this everyone would be happy as it puts much less load on the extruder to push it through a 0.5mm hole.

I've researched a few... and they were all Nylon.

Here's one such link...
[www.nylontrimmerline.com]

TC

Nylon is a thermoplastic that I have been wondering about using. It is stronger than ABS, but I think the nylon gets soft enough to extrude at a high temperature. Once I get a working extruder, I will try some trimmer line and see how it works.


Mike

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I tried pushing trimmer strand through my extruder and I don't think it worked. Maybe it was too hot? It went through, but it was kind of blackened. I am too new to this to offer valuable input, but at the moment I feel like trying it again is not that good idea. It was a pain to clean the extruder nozzle!

JIQ

If Nylon is a thermoplastic, then I think that it is just a mater of learning what the magic temperature is for working with it.

Anyone have a system that you can fine-tune the temperature of while leaving a sample on it and watching it? Maybe a hotplate? Place a sample on it and slowly turn up the temperature. Recored the temperature at which it starts to soften and then continue until it starts to burn and record that temperature. That would give us a range for working with it.

But nylon trimmer line maybe common, but how much does it cost per pound compared to what we use now? If it cost more then what would be the value of using, it unless there is some property nylon offers that the others don't?

Well that's my two cents.

trescott2000 Wrote:
-------------------------------------------------------
> If Nylon is a thermoplastic, then I think that it
> is just a mater of learning what the magic
> temperature is for working with it.
>
> Anyone have a system that you can fine-tune the
> temperature of while leaving a sample on it and
> watching it?

Yes, I do. It´s called DSC and I have performed testing for my thesis on a variety of Polyamide types, i.e PA6,PA6.6,PA12.
All of them have a Tm of above 200°C, you should be expecting the melting peak at arround 220-240°C.
It´s no big deal and the values can be checked at every corner. The question would be if the nozzle could heat up high enough.

According to MatWeb (http://www.matweb.com/search/DataSheet.aspx?MatGUID=fb48404b7e04433bb3ee3d2a0af922ff&ckck=1) Nylon does not decompose until 570 degF and needs to be processed at temperatures between 428-572 deg F. I work in polymer molding and everyday I see PA6 and other Nylons regularly take 500-530 deg F temps and not burn or decompose. Therefore i would think that trimmer line should be able to work in a RepRap style device if your nozzle temp is stable and repeatable. Verify the actual temp with a non contact therm to be sure. I am going to try it in my printer as soon as I get a new cartridge heater that will bring the temp that high. I will post my results.