How Horizontal Bending Machines Form Accurate Bends

Working Against Gravity

Bending on a horizontal machine is different to bending on a vertical machine. On a horizontal machine the bending force acts sideways to the axis of the machine and therefore the workpiece is laid flat on the bed of the machine. There is no weight of the workpiece pulling it down the bed and round the bend which can cause the work to pull out of the bend prior to the full bend being completed. This is particularly important for long workpieces where a vertical machine would allow the end of the work to sag prior to the bend being completed allowing distortion to occur.

Choosing the Right Former

The former, which is the curved surface of the bending tool that the metal is wrapped around during bending, forms the inner radius of the bend. The former can be made in a variety of sizes to allow tight radius bends to be formed and larger radius bends. A common selection of formers for section bending machines are pre-set for a range of different bar and tube sizes, so it is important to choose the correct former for your work piece before attempting to bend it.

Setting the Stop Finger for Repeatability

When Accurate Bends are a Must the stop finger or backstop on a horizontal bending machine must be accurately set to a predetermined length so that each individual piece of work, when bent, will arrive at the same point.

Allowing for Springback

Also the tooling on a bending machine is set at an angle to allow for spring back after the bend has been made. This can be anywhere from a degree to 10 degrees past the intended finished angle. This depends greatly on the steel being used and the wall thickness. A good rule of thumb is to set the angle for the first piece and then do a trial run to see if it is required to be adjusted.

Building Complex Profiles Sequentially

A single piece of stock can go through a number of bending operations to form a complex section such as a frame or bracket. It is essential that precise measurements are taken between each of the bending stations to achieve the correct overall profile. HSE guidance on safe use of machinery in metalworking should be read prior to setting up production.

By getting these 5 aspects correct you can rely on your horizontal bending machine to create accurate bends throughout a full run.