Acceleration?

[rumpel 0]

It does not appear that Cura is honoring the acceleration settings in my custom firmware. Is there a way to get it to use acceleration correctly?

I currently have acceleration set in marlin to 200 and when this is used correctly there is audible acceleration going on with my motors. This does not seem to be the case.

Maybe in the start gcode or something?

Appreciate any help!

Thanks!

 

[illuminarti 18]

Cura (nor any other slicer) does not know or care about acceleration. They simply define the path that they want the head to take, and the nominal speed to aim for. Marlin itself is responsible for handling the acceleration to get the head from whatever speed it starts at to the nominal speed, and then back down again to whatever speed it needs to be at the next corner.

What makes you think that acceleration isn't happening? What speed are you printing at?

 

[rumpel 0]

printing really sloooow right now, printing parts to redesign a mill... 3mm per second

I guess i am not 100% sure its not doing it, I do know that there is a different sound to the stepper motors when acceleration is ramping up and down. This is not doing any ramping up or down, just going speed x to its destination.

 

[illuminarti 18]

At 200mm/s² acceleration, and a top speed of 3mm/s, Marlin is only going to take 0.015s to accelerate. I very much doubt that you'd be able to hear that.

 

[rumpel 0]

ah okay, maybe its just i'm printing so slow. I'm printing a new drive system so I will be printing much faster and I will need to make sure acceleration is moving at that time. Appreciate the advice.

 

[illuminarti 18]

Yes, don't worry - if it's worked for other slicers, it'll work fine with Cura... acceleration is totally internal to the firmware (unless you deliberately override that in your gcode to change the acceleration settings) .

Even then, bear in mind that acceleration times are usually pretty short - and less than expected because of the need to speed up and slow down again during each move. Even with a top speed of say, 100mm/s, with 200mm/s² acceleration, you need an uninterrupted path length of about 50mm before you'll get the full 0.5s of acceleration.