Ground surfaces are an element of the design; matt blasted surfaces are a further possibility. Typical grit finishes for ground sheet metal are 120 grit, 180 grit and 240 grit. Ideally, the structures are designed with few or no weld seams, as they would interrupt the grinding pattern. Weld seams and rough sheet metal surfaces must be ground for hygienic reasons particularly in food and beverage technologies, usually using roughness values of Ra < 1,6 µm or Ra < 0,8µm.