Review and analysis of performance and productivity of size .hammer again. Comminution is also done by rubbing the space between the hammer and the screen. For efficient operation of grinding in hammermill, following items is to be considered. (Doerksen 1993): i) Product .. biomass to be processed in four different ways: impact, attrition, shear, and compression. In hammermill.differentiate between attrition and hammer mill,Size Reduction - Visual Encyclopedia of Chemical EngineeringRaw materials undergo size reduction through different mechanisms: impact, compression, and attrition. . The hammer crusher , also called the hammer mill, is an example of an impact crusher. . Additionally, hammer crushers and fixed knife mills are used for various food applications, such as fruit juice production.