Rolla-V Tooling: The Ultimate Solution for Mark-Free Bending and Short Flange Challenges

In the traditional air bending process, the sheet metal slides over the shoulders of a static V-die. This movement creates friction, resulting in “die marks” or “witness marks” on the underside of the workpiece. For industries working with stainless steel, aluminum, or pre-painted materials, these marks represent a significant cost in secondary polishing. MIHARTING’s Rolla-V tooling represents a paradigm shift, replacing sliding friction with rolling contact to achieve a flawless finish.

1. The Mechanics of Rolling Wing Dies

Unlike standard dies, a Rolla-V die features two rotating “wings” or inserts supported by high-precision rotors.

• The Bending Physics: As the punch descends, the wings rotate with the material. The sheet metal stays in a fixed position relative to the wing surface, meaning there is zero scraping.

• The Result: A significant reduction in surface tension and the complete elimination of carbon steel contamination on stainless steel parts.

  
  

2. Technical Data: Tonnage and Ratios

Engineers must understand that Rolla-V tooling behave differently under load than standard V-blocks.

• Tonnage Reduction: Because the material rolls rather than slides, the friction coefficient is reduced by approximately 15-20%. This extends the life of the press brake’s hydraulic seals and the tool itself.

• The Minimum Flange (b) Formula:

  In a standard V-die, the minimum flange is typically $b = 0.5 \times V + r$.

  With MIHARTING Rolla-V, the minimum flange can be reduced to $b = 2.5 \times t$ (where $t$ is thickness), allowing for much tighter geometries near the bend line.

3. Industry Insight: Solving the “Short Flange” and “Hole Near Bend” Dilemma

A common nightmare for fabricators is a hole or slot located close to the bend line. In a standard V-die, the hole will “flare” or distort as it passes over the die shoulder. MIHARTING’s Rolla-V inserts support the material throughout the entire rotation, preventing the hole from falling into the V-gap. This makes it the premier choice for electronics enclosures and aerospace components.

4. Maintenance of Precision Inserts

To ensure 1,000,000+ cycles, MIHARTING recommends:

• Debris Management: Use compressed air to clear scale from the rotors every 500 strokes.

• Lubrication: Use a dry PTFE spray. Avoid heavy grease, which can trap metal dust and create an abrasive paste.