Spin coating is a procedure used to deposit uniform thin films onto flat substrates. Usually, a small amount of coating material is applied on the center of the substrate, which is either spinning at low speed or not spinning at all. The substrate is then rotated at a speed of up to 10,000 rpm to spread the coating material by centrifugal force. A machine used for spin coating is called a spin coater, or simply a spinner.

I was trying to make a suitable box for my Spin-Coater.

Spin-coating is made from 3000–10000 RPM.  One of the necessary parameters to control the thickness of the layers is the rotation speed, which becomes thinner with a higher speed.