Advice for printing nylon through fine screen
I'm trying to print nylon onto a fine screen; the goal is to impregnate the screen with the nylon, so "print through" the screen.
I inserted a pause in the startup code, right after the purge line is printed. At that point I place the screen on the bed, held down by magnets. I have no idea what the temperature of the screen is; it's partially pre-heated, sitting on the bed during warm-up but removed during homing; it is then on the bed for some time (30-60 sec?) before resuming printing.
The image is from:
nozzle: 0.25mm, 270 deg C bed: 120 deg C height: 1 layer, 0.2mm filament: MatterHackers Pro nylon
Issues:
1. The first few dots printed were in the lower left corner; note how they appear thinner, and appear to have printed through the screen. Is this because the nozzle is hotter, from waiting for the print bed to reach target temp? (The nylon is pretty runny at this temp)
2. Many of the dots appear to have excess nylon in the centers. This looks to me like too much material is being extruded, possibly due to flow continuing due to high nozzle temp. What would be good ways to try to deal with this?
Any thoughts on how to improve the process would be much appreciated.
Don't forget that if you're printing into a mesh there is aleady a varable quantity of material in place - there might be none in a 'hole' next to perhaps 50% of the space pre-filled where three or four strands come together.
Later layers should be relatively OK.
Cheerio,
RE: Advice for printing nylon through fine screen
Additional info:
I changed the advanced extrusion rates to all be at the default, (no overextrusion); it didn't make much difference.
I tried upping the temp to 275 C, with a small improvement.
Finally, I thought the changes in direction from the internal fill pattern (rectangular), might be the problem, so I changed the number of perimeters to completely fill the hole; that helped significantly, although most circles still have some excess filament