If you are familiar with metal fabrication and very often get to see sheet metal bending your own eyes, you may notice a slight thrust from the sheet metal after the press brake machine is done enforcing it with a specific pressure. This is called springback by metal fabricators.

What is Springback?

It is more like a pushback from the material itself than a thrust. This pushback from the material is caused by its elasticity. In simple terms, elasticity is the natural characteristic of an elastic material that leads a distorted object to try to achieve its previous form to an extent when the force is withdrawn from its body.

Due to the elasticity of sheet metal, it tries to get back its previous form before the metal bending and this is how we get springback from sheet metal. So Springback is actually a geometric change that happens to a part of the sheet metal when the metal bending is done and the sheet metal is released from the force of the press brake machine. In a sense, it is just the metal trying to spring back to its original shape and thus the term Springback.

Is it possible to predetermine the Springback?

Although calculating the spring back is extremely difficult, it is not impossible in any sense.

There are few factors to consider while estimating the springback. First of all, fabricators should know the Modulus of Elasticity (MOE), which is known as Young’s Modulus. This is an important factor to predict distortion and elasticity. Apart from Young’s modulus, you need to know the included bend angle, material thickness, bend radius, K-factor, and the yield strength.

Calculating Springback

Although this might seem like extremely tough, especially when I’m bombing you with all these geeky factors, actually, it is not. Fabricators don’t even need to calculate the MOE, Yield Strength, and K-factor. They will be available online because they are almost constant for specific material. You just need to put it in these equations.

V = (Ir×Y)/ (MOE×Mt×1000)

Sf = [4× (V²)–3] ×V+1

Ra = Ir/Sf

Af = [{Ir+ (K × Mt)} ×A}]/ {(K×Mt) +R}

Sd = Ir–Af

If the equation is filled with proper values of Young’s Modulus, K-factor, Yield Strength, Angle, Final Angle, and Inside radius, you will be able to determine Springback, Final angle, springback factor, etc. no matter what you are doing this for, stainless steel fabrication, aluminium fabrication or steel fabrication.

Although they won’t be 100 percent accurate, they’ll give you a close estimate and if you are somehow related to metal rolling, metal bending, laser cutting or any type of metal fabrication process, you’ll need as much statistical and analytical help as you can get.

So, now that you know calculating springback is possible, you can easily determine the outcome and take precautions likewise.