Firmware

What acceleration, retraction acceleration, jerk, and feedrate, should I be using? Also, what should I set my printing speed to in Sli3er?

There are no hard and fast settings for this. You need to find what your machine is capable of and make sure you limit it to that by setting your firmware values. It all depends on how well the printer is designed and assembled and to some point the quality of the parts. Because of this no two printers will be the same. As a guide start low then work your way up after a few test prints these are just some rough numbers for you to try, I'm sure others will suggest different

#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 45} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {750,750,100,10000}

#define DEFAULT_ACCELERATION 500 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for r retracts

#define DEFAULT_XYJERK 10.0 // (mm/sec)
#define DEFAULT_ZJERK 0.4 // (mm/sec)

As for slic3r speeds, start with all the printing speeds at 50mm/s, first layer at 30mm/s and travail at 100mm/s.

One you get consistent good prints, start playing with the numbers to find your limit, always keep notes so you know what you changed

The good news is you can alter these on the fly sending the appropriate gcode. So make a tower and print it changing one of these parameters every 5mm, see what effect they have.

Acceleration being too low only slows down your prints, quality will be good with low acceleration. Go up as high as you can without quality reducing, that's your optimal setting.

Jerk - some claim too low and your corners will be round, too high and they will be very bad as the stiffness of the frame and mechanics can only handle so much instantaneous speed change, you might even skip steps and end up with a piece of modern art.

Max feed rate you can experiment with, set it very high in firmware and then move axes back and to, a fixed distance, at increasing speeds (feedrates) until you don't get the correct distance or the motor stalls. That's your max for a given voltage and motor driver current (aim for 70% of max for your motors to keep motors from getting hot).

My understanding of the retract settings they only apply to firmware retraction, when almost all retracts are slicer generated.

Edited 1 time(s). Last edit at 02/24/2017 08:00AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions