Advise to get faster Prints ?
January 10, 2014 04:14PM
Hello,

I am using a Prusa I3 and I am using Kisslicer and Slic3r for my prints.
I am printing PLA 1,75 mm with a jhead nozzle.

I try to print large prints, for example the blossoming lamp from thingiverse.

The lamp took about 9 hours ... or so ... some users reported they have print that in 4 and a half hour.

Is it somehow possible to get my prints even faster ?? I have set my perimeter to 80 solid infill to 100 and sparse to 130 ... in kisslicer

but my extruder feedrate is limited to 45 mm/s in marlin.

Do I have to adjust the feedrate to get even faster prints or what should I do ?? I think the speed is limited because of the feedrate right ?
And if so how can I calculate my feedrate ??
I am using a Greg wades extruder with 47/9 ratio and fishbone gears.
Re: Advise to get faster Prints ?
January 11, 2014 03:09PM
FEEDRATE = Travel Speed
FLOWRATE = Extrusion Speed

It's neither here nor there, as these two values should normally be the same if using volumetric extrusion, which almost every firmware out there is doing now.

What is most important in determining the upper limit of your printing speed would be:
1. The maximum sustained speed that the extruder can run at, without overtaking the hotend heating rate.

If your power supply can handle it, you can reduce the resistance value of the hotend resistor a bit to get more heat in faster. You can also try running the hot end hotter(<240°C!), but make sure you are running fast enough that you don't accumulate heat in the insulator.

2. The maximum combination of acceleration, and speed of the X/Y Axes that does not skip steps, or melt your motors.

Jerk Limit, Ramp Acceleration, Max Feed Rate are all values you can fiddle with in the EEPROM settings of most firmwares. Try changin one value at a time, and see how it affects the motion of your printer.

Edited 1 time(s). Last edit at 01/11/2014 03:10PM by jcabrer.
Re: Advise to get faster Prints ?
January 11, 2014 03:23PM
I think the extruder feed rate is specified in terms of the feed (3 mm or 1.75 mm diameter filament) and not the extruded filament which comes out at slightly larger than the nozzle diameter. So, 45 mm/s in the feed would be roughly 1.75/0.35)*45 mm/s= 1125 mm/s extruded filament if you have a 0.35 mm nozzle. That's plenty fast.
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