Please help! 1mm Nozzle Settings

[carlzoll]

I'm currently using a .3 mm nozzle and the print jobs are taking over 9 hours to complete. I purchased a couple of .5 mm nozzles and drilled one out to 1mm. I'm using Slic3r but not sure of the settings once I change over to the 1mm nozzle. ANY help on this would be GREATLY appreciated!

Regards,
Carl

[Alibert]

I wiil leave the advise on the Slic3r settings to someone with more experience with Slic3r, however I do have my two cents worth on your intended goal (which is the same I have been working on as well).

I have experimented with nozzle sizes of 0.5 - 0.6 mm on a kossel max type delta printer and found that the limiting factor became the maximum amount of plastic VOLUME (in cubic mm/s : mm3/s) the extruder can push out without slipping. As the filament goes through the hotend, it has to heat up (takes energy and time) and melt (also takes energy and time). As the heating cartridge is not directly on the filament but embedded in the heat block, that energy has to go from the heating cartridge to the nozzle. This will induces a temperature gradient from the cartridge to the nozzle (which is the driving force for the transfer of the energy, analogous to voltage being the driving force to drive curent through a resistance). Without a temperature gradient, there will be no transfer of heat, so the gradient is a requirement for the heating block to function. The faster you extrude, the higher this temperature gradient will be. The viscosity (and thus the pressure required by the extruder to keep things moving) depends on the plastic type and thermal properties, nozzle dimensions and the temperature at the inner nozzle wall in contact with the filament.

With a 0.5 nozzle printing at 0.4 layer height using a Bondtech extruder (very high torque) the extruder can't keep up at a max speed of 3000 mm/min (50mm/s) as the amount of plastic (0.5*0.4*50 = 10 mm3/s) is too much to get up to flowing temperature. This is eviedent as with long straight lines (infill) the plastic is coming out very irregularly and much thinner than intended. Increasing the nozzle temperature setting does help a bit, but at 10 mm3/s the filament is theoretically moving at more than 4 mm/s through the hotend. with a length of roughly 12 mm in the hot part of the nozzle, that means 3 seconds to go from ambient hard plastic (cool part) to fluid low viscosity melted plastic. Even the Bondtech (can lift a 17 KG weight without slipping) is not capable of that, so I have to lower the printing speed thus negating my intentions of faster prints.

I have ordered a volcano type hotend to increase the hot end length and thus resisdence time of the filament in the hot part. When I have it in I will run more tests and see if the extrusion volumetric speed in mm3/s improves significantly or not.

Reasoning from the other side, if for example 7 mm3/s is the maximum your extrider/hotend will support (my experience with a number of extruder/hotend combinations), then with a 0.4 mm nozzle at 0.35 layer height you already achieve 7 mm3/s at a slicer speed setting of 3000 mm/min. The popular 0.4 mm nozzle thus seems to be that popular for a good reason. Only with a better extruder/hotend system will you be able to print faster.

[Sebastian Finke]

1mm! Wow! You may need to slow things done a bit to get the necessary throughput.