Movement Inconsistency in X and Y axis

Hello All,

I just build my DIY clone of X Carve using Arduino and grbl shield. 1000 mm size.

Issue 1 - Using Easel , when i jog X axis for 100 mm it sometimes moves 100 mm and sometimes it moves 98 mm. What might be the issue here.

Issue 2 - Below are the values that i found correct and after that the machine became very very slow when carving or jogging.

$100=5.00 (x, step/mm)
$101=5.00 (y, step/mm)

Please please help me.

Thanks in advance.

Check belt tension and the pulley on the stepper for slippage and also might need to turn up the voltage for the stepper.

Thanks Shane.

I assembled the belt very tight hoping that it will loosen up after some use.
I will reduce the tension and pulley grub screws when i get home tonight.

How to turn the voltage. I am using below components.
Nema 23
CNC Shield V3
A4988 drivers
24V 10A power supply (is this enough?)

And when i keep the parameters $100 and $101 to default values (250), for 1mm machine moves 50 mms at a very good speed.
But when i change the values of the params to 5 , machine slow but 1 mm is 1 mm (close)

Any solutions?

Have not messes with the a4988 but this might help in voltage adjustment