Mill screens are used to help manufacturers get the right particle size while milling. There are two important factors that help you pick the right screen, hole shape and size. The hole shape is determined by whether the material being milled is wet or dry. The hole size gets you the right particle size!

Screens are sized by the diameter or width of the hole. It’s possible to pick the right screen by both Metric and inch dimensions. As an example, use the popular size of 0.0394” which is 1mm. These correspond to a US Mesh size of 18 Mesh. To know your Mesh to inch or Metric conversions you will need to refer to the Quadro Comil Particle Size Chart. Contact me for a higher-resolution chart.

The four most common types of screen holes are round (R), grated (G), square (Q), and slotted (S).

The most common screens used in pharmaceutical manufacturing are round and grater as they are used for dry milling. Round screens can limit the number of fines – small dust particles. Grater screens are used to break down fibers or reclaim tablets. Square and slotted screens are for wet milling.

You will find everything you are looking for in the manufacturer's part number on a Quadro Comil screen. Here is an example part number: 2C039R03125.

Let’s break down how to read it:

• 2C refers to a model 194 Quadro Comil.
• 039 is the hole opening in thousandths of an inch.
• R means it is a round hole.
• 031 is the thickness of the screen in thousandths of an inch.
• 25 represents 25% let through on the screen.

Quadro Comil Model Designation 

• 2A is for model 197
• 2C is for model 194
• 2F is for model 196
• 7F is for model U30

Hopefully this helps with choosing the correct screen for your application! We sell Quadro screens and parts for model 194, 196, 197, U20, and other Comils.

Need further help? Contact PharmParts.

Need help selecting the right mill or Quadro Comil? Read Federal Equipment Company's blog post, Milling for Tablet Making.