Calculating Springback In Sheet Metal

After a bending operation residual stresses will cause the sheet metal to spring back slightly.

Calculating springback in sheet metal. Due to this elastic recovery it is necessary to over bend the sheet a precise amount to acheive the desired bend radius and bend angle. Upon completion of sheet metal forming deep drawn and stretch drawn parts spring back and thereby affect the dimensional accuracy of a finished part. The final bend radius and bend angle can be approximated from the sheet thickness k factor material yield strength and modulus of elasticity and the initial bend. Sf is the relationship between the beginning and ending angles.

Like bend allowance precisely determining springback isn t completely predictable. To determine the actual radius ar you get after springback multiply sf by the original inside bend radius that is the expected or planned radius before the metal springs back. Springback is the geometric change made to a part at the end of the forming process when the part has been released from the forces of the forming tool. This type of springback problem is easily adjusted for by adding simple over bend or compensation.

To find the springback before testing it is crucial to understand that the angle and bend radius vary depending on the springback. When the proportional limits of a specific material are reached or exceeded the material remains bent figure one. A spring back factor of ks 1 means there is no spring back where a value of 0 means total spring back. K factor ratios also play a big role in calculating springback in sheet metal fabrications so do trial and error prototypes as well as personal experience of the fabricator.

You can find the initial angle by doubling the initial radius by 2 dividing the number by the thickness of the metal and then adding 1. The final bend radius and bend angle can be approximated from the sheet thickness k factor material yield strength and modulus of elasticity and the initial bend angle and bend radius. That is sf bending angle bent angle. This springback and inside radius calculator estimates the amount of angular change and the relaxing of bend radius that occurs when metal is bent and released from pressure.

Springback occurs when a metal is bent and then tries to return to its original shape. The spring back factor commonly denoted by ks is the relation between the initial and final angles. This is where the springback factor sf comes into play. There is a more advanced formula that you can try.

Calculate and mitigating the springback effect in sheet metal simple straight line bending will exhibit springback produce a simple 90 degree bend in any given sheet metal thickness of any grade and springback will occur.