Percent Open Area (POA) is the ratio of hole area to total screen area at a 90° angle of incidence to the plane of the material, expressed as a percentage. Material with 40% open area will have 40 square inches of opening for every 100 square inches of material. Percent open area helps in comparing various materials as to how easily a product, air, or light, will pass through the screen. In the visual below, we placed an apple behind the example mesh to demonstrate how the POA affects what can be seen.
Mesh to Diameter Ratio (MD) is the mesh spacing (center to center) divided by the wire diameter. As a manufacturer, this is very useful to us as MD is used to help determine the optimal crimp style to use in the various mesh to diameter relationship scenarios. By selecting the most favorable crimp style, we are able to provide a higher quality mesh more efficiently. Aesthetically, the lower the MD ratio, the more heft the wire mesh will appear to have; the higher the MD ratio, the less heft a mesh will appear to have.