Rotary Benders

Similar to the folds in a greeting card or letter, sheet metal can be folded along its length or width to create parts and panels. These folds, referred to as bends in metal forming, can be accomplished in multiple ways. One method uses wipe tooling in a die press or press brake. The sheet metal is bent between a forming punch and die with the downward force of the ram.

Another method, which we’ll explore here, is rotary bending. First we’ll go over the operational principle and configuration behind rotary benders. Next we’ll examine the advantages rotary bender technology gives you and some of the many industries and applications that benefit from rotary bending. We’ll also list the factors that determine which rotary bender set up is best for your needs.

Rotary Benders Explained

In rotary bending specialized rotating benders are used to create bends in sheet metal inside a punch press or press brake. Benders consist of a long, spring-loaded cylinder, or rocker, that rests and rotates in a form-fitting foundation block called a saddle. A lengthwise V-shaped groove is machined into the rocker to match the desired bend angle. As the rocker rotates smoothly in the saddle, it pushes or rolls over the sheet metal and gently forms the desired bend.

The bender assembly is typically mounted above where the sheet metal is fed into the press. As the bender moves down, the rocker makes contact with the sheet metal. One contact point acts as a holding pad, while the opposite contact point rotates, creating the bending action.

This illustration clearly shows the different operating principles of a rotary bender and wipe tooling.

Rotary Benders Advantages

Standard or custom rotary benders offer a number of advantages over wipe tooling, such as:

• The ability to holds consistent part angle tolerances of +/- ½ degree
• Consistent leg heights so that no cams or restrikes are needed
• A more gentle, rolling motion during bend forming that leaves no galling or other marks – especially important for highly aesthetic or painted materials
• Minimal distortion of holes located near the bend
• Many options for angles and shapes including square, oversquare, undersquare, short leg, zee bend, channel or hat bend, large-radius bends, and closed or precision-open hems. These Classified Bends (CB) and more are illustrated here.
• DIY bend angle adjustability – simply shim or grind the “jaw” angle of the rocker (up to 135 degrees total for oversquare bends to counter springback)
• Up to 50 to 80 percent lower forming tonnage required
• Optional test bending service – especially helpful with painted and aesthetic materials or any critical application

Rotary Bender Applications

Many industries use or manufacture equipment and components that call for bends in sheet metal. These include the automotive, aviation, office and industrial furniture, construction, industrial enclosures and other industries.

Some sample applications include, but are not limited to:

• Automobile and truck panels
• Aircraft panels
• Metal cabinets, shelving, and brackets or other supports
• Housings and enclosures for electrical and other components
• Equipment panels
• Appliance and HVAC cabinets, enclosures, and panels
• Metal railings and bench components, long brackets or nosing strips for securing flooring, roofing, or other materials in construction applications

Rotary Benders From Ready Technology

Standard and custom rotary benders are available. Several critical specifications are used to determine which bender is appropriate for a given application, including:

• Material type and thickness
• Part length and height
• Bend angle and radius
• Annual production volume
• Intended operational use: stamping die, automated machine, press brake, etc.

Whether you know exactly what you need or aren’t quite sure yet, our team is here for you. We can discuss your requirements and help you select a rotary bender configuration that is efficient and durable – please contact us today or request a quote to learn more!