Hello. I need assistance regarding my engraver. The problem is whenever my engraver do makes a line. Each and every line starts with a little waving whether vertical or horizontal. In this picture i burned a square and circle. The circle is fine but each start of every lines on the square has few waves…
You might need to play with your accelerations
or just slow it down
This is a fight with physics and the mass of your laser head
That was fast. Thanks. Yes i tested it out and found that whenever i slow the speed down to maybe 1500mm then it will become barely noticeable but still there.
Is this waving before each line normal?
Sorry what do you mean accelerations? Is it the one on top of power on cut/layer tab or there are other settings to fiddle?
So… your machine firmware has a few settings, this will be a over simplified explanation
Max size, steps per mm, max speed speed and also the acceleration speeds
This means as your machine is moving from LEFT to right, and it knows it has to stop, it computes how FAST it can slow down and then accelerate back to speed without creating engraving artifacts.
Best example would be. if you have a Ferrari, you know you can stop in 30 meters even if you are driving at 100kmh, and the car won’t even sweat it
if you ave a Renault Twingo, you … will be in trouble to stop in that distance without half the car falling apart! 
Now as you notice on your squares the machine is showing the frame is not stiff enough for the levels of acceleration/Deceleration it’s trying to do, so you could slow those down a bit.
However, slowing the overall speed will be simpler and achieve the same overall results.
Something else you might want to see too is where the center of mass of your laser module is.
Depending on your frame, if the laser is very low vs the X axis rail, you might be amplifying the problem by having harmonic vibrations on the X axis (basically your laser module becomes a pendulum)
Edit:
Full explanation of GRBL settings
https://github.com/gnea/grbl/blob/master/doc/markdown/settings.md.
You want to focus on accelerations
https://github.com/gnea/grbl/blob/master/doc/markdown/settings.md#120-121-122--xyz-acceleration-mmsec2
Thanks for the explanation. I will give it a fiddle tomorrow and give you my test results. Thanks so much!!
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If that doesn’t work… I think your belts are too loose.
What is occurring is the head is changing direction and the gantry/head are still moving. It’s sometimes referred to as ringing or oscillation from changing direction… I notice it on both your axes.
My machine does this under two conditions: belt tension low, or acceleration too high. Start with tension, but there is still a point where increasing tension cannot overcome the inertial forces.
Generally I’ve found acceleration values to be very conservative from these manufacturers. So I’d suspect a mechanical issue.
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