Nylon filament

I broke my M90 x-carriage cooling fan bracket. One of the little lugs snapped off.
I printed a new one in PLA. (It functions much better than ABS as it's stiffer and holds the fan assy. pretty much parallel to the bed so there's a little more naked nozzle showing and less chance of catching.)

I printed the bracket again with some Taulman 618 nylon just for fun.

At a nozzle temperature of 238C the result was acceptable (after a bit of clean up to remove trails) and incredibly tough. There was a bit of snap,crackle and pop as it printed.

At 228C the surface finish was much better (much reduced s,n&p) but it was relatively easy to separate the vertical part of the bracket.

I tried 210C; the surface finish was really excellent but of course it delaminated instantly I took it off the bed.

I realise I ought to try drying out the filament (I used a new spool sealed in a bag with desiccant, but it might help I guess).

Has anyone printed parts (rather than RichRap's incredible vases etc.) with 618 and achieved toughness and a good surface finish?

Interesting and very encouraging. Did you print onto cold glass or some other base material? Were you using a standard Dibond kit machine with a 0.4mm nozzle?

Alan

Yes, it was a standard Dibond M90 from nophead with a 0.4mm nozzle.

The base was glass, smeared (when cold) with a thin layer of PrittStick*. (If the glass is hot/warm the glue doesn't go on evenly.) The printing was at a bed temperature of 90C throughout. This allowed good adhesion during the print and fairly easy removal when cold (water + scalpel).

*PrittStick : Maybe called something different outside the UK? Basically a water soluble glue stick. Someone has used UHU Stic with good results I read somewhere. I used a very old PrittStick with success. A PrittStick I bought yesterday didn't seem to work quite so well however. It said "new formula" on the tube so that might be a problem or it maybe that I didn't keep the bed temperature high enough as the print lifted at one corner half way through. I shall try it again tomorrow.

Almost there now. Drying the filament for 4 hrs at 80C made a huge (unbelievable) difference. It almost totally removed the snap, crackle and pop, and greatly reduced ooze.

At an extruder temperature of 240C and print speed of 30mm/s for perimeters and 60mm for infill, I can now get excellent finish at .3mm layer height. The M90 fan bracket I'm printing as a test piece is indestructible with bare hands.

Some notes:
1) It seems better to keep the printing speed up rather than down otherwise the extruder stops extruding adequately. It may be that I need a higher roller pressure (but I checked the extruder accuracy and it seems better than 1%).
2) There sometimes seems to be a bit of delay between the extruder motor starting and extrudate appearing. This makes layers start and end approx. .3mm late. Maybe roller pressure again.

How flexible is the bracket when made from Nylon? All the printed nylon objects I have seen seem very flexible.

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[www.hydraraptor.blogspot.com]

Yes, it is very flexible indeed. I can twist the bracket 45 degrees end to end easily so you wouldn't want to make a production bracket from it without additional bracing.

The attraction, for me, is it's toughness; the upright that attaches to the x-carriage is only 3mm thick yet it's utterly inseparable (by hand) from the fan mount. Also, the fragile end lugs just bend rather than snap when you abuse them.

Considering I didn't even print at the optimum bonding temperature for 618 I am rather impressed.