Maasi: A 3D printed spin coater with touchscreen

Spin coaters are widely used to apply thin films of a material uniformly over a flat substrate. Despite the simplicity of this technique the entry price for such machines might be prohibitive, ranging from few hundreds to thousands of Euros. Here we present Maasi, an affordable alternative that is easy to build and has all functional key features to be used in a wide range of applications. Our design has a price of less than hundred Euros and an assembly time of only two hours. One of the key design principles was to use only 3D printed parts in combination with affordable Commercial Off-The-Shelf (COTS) components [1]. Reducing the complexity we use an electronic speed controller (ESC) with telemetry, to eliminate the need for a rotor position sensor [2]. A touchscreen further improves its usability, thus setting a perfect startpoint for the design of other affordable lab tools. The Maasi project includes different 3D printable substrate holders allowing treatment of formats up to 80 mm in diameter. We furthermore validate the Maasi spin coater by measuring its speed accuracy and performance for coating polydimethylsiloxane (PDMS) on glass coverslips for mechanobiological assays.