To help our site visitors understand the roll forming process, Corrugated Metals, Inc. has included this roll forming tutorial. Part 4 addresses Quality and Accuracy, Common Roll Forming Applications, Roll Forming Tooling, and Operating Parameters.
Two situations that may negatively impact the quality and accuracy of roll-formed sections are springback and end flare.
Springback occurs when the material to be formed has not been stressed past its elastic limit. Springback can be engineered out during tool design by overforming the material beyond its anticipated final shape.
End flare is the deformation at the ends of a roll formed part. End flare can be eliminated or at least reduced through using proper roll forming tool design.
Roll forming, as a metal fabricating process, is used in many diverse industries to produce a variety of shapes and products. Roll forming is a desirable process since it adds both strength and rigidity to lightweight materials.
Some industries that frequently use roll-formed products include:
Tooling used in roll forming includes the forming rolls and the dies for punching and cutting off the material.
The rolls are the tools that form the moving through the roll forming machine. The number of passes the material makes depends on the complexity of the part and the properties of the material to be formed.
The creation of the flower is the first step to be undertaken in the design of roll tooling. The flower is the station-by-station overlay of progressive section contours starting with the metal strip and ending with the required component profile.
The two major considerations in designing the flower are:
- a smooth material flow from first pass to the last pass; and
- utmost control over fixed dimensions while roll forming.
A number of standard materials are used to manufacture the roll forming rolls. The type and shape of material being rolled and the quality of parts being produced are key factors in the selection of the roll material.
The most extensively used material used in manufacturing rolls is an oil-hardened tool steel that has been hardened to RC57-60. For excellent tool longevity, tool manufacturers should use a high-carbon, high-chrome tool steel, hardened to RC59-60.
Cast aluminum bronze is a good choice forming deep sections that have sliding motion since it possesses good frictional qualities. Roll forming vendors should chrome plate their rolls if they need to sustain a highly polished finish or prevent painted surfaces from being damaged.
The roll forming operation increasingly forms material as it passes from one forming station to another. The changeable parameters in a roll forming operation include power requirement, speed, and type of lubricant used. These parameters are determined by width, thickness, and type of material, complexity of cross section, coating on material, and the accuracy required.
Auxiliary operations such as prepunching, embossing, curving and coiling, and cutoff, incorporated in the roll forming line, also influence the parameters at which a roll former must operate.
Previous: Part 3 of the roll Forming Process discussing materials that can be roll formed, the kinds of tolerances that can be expected from the roll forming process, especially as they regard material straightness.
Roll Forming Tutorial Sections
- What is Roll Forming?
- Roll Forming Techniques
- Roll Forming Design Issues
- Roll Forming Advantages and Limitations
- Materials That Can Be Roll Formed
- Tolerance Expectations
- Quality and Accuracy
- Common Roll Forming Applications
- Roll Forming Tooling
- Operating Parameters