K Factor depends on material composition and percentage of carbon contents. In this Figure-1, the K factor can be calculated as (δ/T). K factor is the ratio of neutral axis location to the sheet metal thickness. But it can be anywhere in the sheet metal. Typically neutral axis is at the center of the sheet metal. The position of the neutral bend line or neutral axis decides the length of the flat part. In FIGURE-1, the red line is the neutral axis. The neutral axis is the line that remains constant irrespective of compression or expansion. The thickness of the sheet metal What is neutral axis in sheet metal.Percentage of carbon content in the sheet metal.Material composition in the sheet metal.To compression this compression and expansion, bend allowance exists so that we get the correct length of the flat part.īend allowance depends on the following factors. On the other hand, the outer portion ( Covered by T-δ) is under expansion that always tries to elongate the part. When a sheet metal forms a bend, the inner portion ( Covered by δ) is always in compression that reduces the part length. Δ= Distance between the inside radius of the bend and neutral axis
