Square corner velocity and smoothness of movement

[nefelim4ag]

Well, first of all.

### Basic Information:
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[x] klippy.log

There are a lot of different things that could happen. From the scarce information that I see, it seems like you do use StealthChop on the ballscrew axis.

Stealth has limited speed range before EM resonance happens:

TMC StealthChop Rotor Positional Lag and Compensation

The problem definition According to the Klipper docs, Stealth has a positional lag. If you have an encoder, you can validate that data on your machine. [Spread vs Stealth] CoreXY 1 motor test Gcode Spread has low lag, less than 1/4 of fullstep distance, which increases with higher speeds (>200mm/s in my case), stealth has a steeper lag increase over a full speed range, and clamps it around 1 full step. Why bother? Well, the open-loop control 3D printer is built around time precision, with …

It would happen around ~5 RPS in general.

@Muz94

was increasing the Square corner velocity from 5 to 10-15.
In this video you can see the difference that going up to 8 made.

Unfortunately, I do not hear the difference. Anyway, basically, SQV is just a speed limiting factor to travel angles, that is, it. The wider the angle, the faster it would travel.

Kinematics - Klipper documentation

If you utilize an input shaper, increase of SQV would increase the rounding on the corners and basically would make angle movements more “smooth” (round).

Analyzing your footages from the Reddit:

-Z, SC ON: https://imgur.com/XgzLbzf

This sounds like a high RPS stealth resonance.

-Z, SC OFF: Imgur: The magic of the Internet

This sounds like normal spread.

• X right, SC on: Imgur: The magic of the Internet

It is silent, and there are mechanical noises.

• X left, SC on: Imgur: The magic of the Internet

It is slightly hitting the resonance speed zone.

Hope that helps.