firmware acceleratrion

Hey guys,

I’ve been comparing the quality of prints on my mp3dp to my old makerfarm i3 prusa and noticed i’m not getting quite the same results. Overall the mp3dp is printing good but i’m getting slight vibrations/ringing on the exterior surface with the 3d printed lines on the exterior surface.

I thought it might have been my bed so I printed new bearing mounts and now that is much sturdier. But I printed another cube last night and I’m still getting the slight ringing. Anyways I went in and compared the firmware and noticed the acceleration settings on the mp3dp are 6 times as fast compared to the makerfarm prusa. mp3dp is set to “3000” where as makerfarm is set to 500. I’m going to adjust the settings and see what happens. I may try setting the mp3dp to “1500” and see what happens though.

I did notice however that the cura gcode estimates for the print time are more accurate on the mp3dp though. I guess the acceleration is more in line with their estimates because my makerfarm always takes longer then what cura estimates. Just a side note.

I’ll report back later and show a before and after…

It doesn’t hurt to go lower. I made a post a while back explaining what I learned about G00/G01, and I talked about acceleration, max speed, and jerk.

You can actually get a higher total acceleration by going at an angle to x and y, so you might want to do test prints at an angle.

There will always be some sort of ringing, usually very very slight though, unless you are going extremely slow. Using mine at 32-35mm/s it is barely noticeable.

There is a trade off, higher speeds or higher accelerations for the same quality total print time. Detailed parts or high infill do best with slower print speed higher accel, large simple parts low infil benefit from high print speed low accel. All comes down to how many times it is going to turn.

How fast are you printing?

I think it’s useful to point out that a hobby machine has different requirements than a production machine. Personally, it’s idle at least half the time, if not more, so I don’t mind if it takes longer to get better prints.

That is kinda what I was trying to say.

Base your settings on the kind of prints you do. I do relatively small intricate prints, so I chose slow linear speed and high accel. But if I did larger prints I would do High linear speeds slower acceleration.

If the you were printing 3’ long boxes on a MPCNC high linear speed and low acceleration you would print faster with the same quality.

I have ringing at and have tried lower speeds as well with no success. I tried setting the DEFAULT_MAX_ACCELERATION to 1500 and the LCD still shows 3000 for the ACCEL, AMAX X, AMAX Y values after uploding. Am I setting the correct values?

What speeds are you printing at? I haven changed the values on mine at all. And i dont have a big issue with it. Youll probaby never be able to totaly eleminate it.

Printed this last night. Not too much ringing. [attachment file=42005]

I’ve reduced to as low as 40. FYI, I’m printing the p-38 from 3dLabs, and I get ringing on the letters printed on the Fuselage and wing(i.e. C.G.) otherwise the prints are pretty good, better than my ANYCubic/bowden setup.

For a direct drive printer 40 is still pretty fast, you have to accelerate and decelerate a lot more weight. If I print at 30 I see almost zero ringing, bring it up to 35 and it is obvious. If some more time was spent accel tuning it you might get a really nice 35 and signs at 40.

Tacos that thing is great!

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Your out line speed is 40? Thats my max speed with a 60% underspeed for the outer walls.

40mm/s is my default printing speed. Outline under-speed is 70%. I’m using S3D for slicing.

There are individual acceleration settings in the firmware. The jerk is also important, because below the jerk number, the accelerations aren’t applied.