How to calculate the unfolded length of sheet metal stamping and bending parts?

Bending parts are a relatively common type of product in sheet metal stamping. Before bending, we often need to calculate the unfolded length of the bent parts to prepare for the previous blanking process. So how to calculate the unfolded length of sheet metal stamping and bending parts? It can be seen from the section of the sheet metal stamping and bending parts that the sheet metal stamping and bending parts are composed of several straight line segments and arc line segments (see the figure below). The unfolded length of the sheet metal stamping and bending parts is the sum of the length of the straight line segment and the arc line segment. The straight line segment can be directly calculated from the workpiece drawing. The arc segment length is calculated according to the arc length calculation formula. Its radius is the sum of the distance from the neutral layer to the inner edge of the corner and the bending radius. The arc length formula is: L arc length (mm) , A bending angle (degrees), R neutral layer arc radius, Ru003dr+kt〔mm), r bending radius (mm), k neutral layer displacement coefficient. Let us use a simple example to get familiar with the application of the following formula, and find the unfolded length of the sheet metal stamping and bending parts shown in the figure below. Solution: It is known that tu003d2mm, a2u003d30°, a4u003d90°, r2u003dr4u003d4mm. So r/tu003d4/2u003d2 look up the table and get ku003d0.45, so L2u003d0.0175×(4+0.45×2)×(90-30)≈515(mm) L4u003d0.0175×(4+0.45X2)× 90≈7.72(mm) The length of each straight line part: L1u003d20(mm) L3u003d32-2-4u003d26(mm) L5u003d20-4-2u003d14(mm, then the total unfolded length of the sheet metal stamping and bending parts Lu003dL1+L2+L3+L4+L5u003d20+515+26+7.72+14u003d7287(mm). In actual production, we often first calculate the theoretical unfolded length, and then use wire cutting to process the sample Come to the bending test, and then make corrections through the test results. Previous: What are the specific requirements for the thickness of the sheet metal for processing stamping parts?