Metal Tips Roll Forming Tutorial – Part 1 Roll Forming Description and Techniques

To help our site visitors understand the roll forming process, Corrugated Metals, Inc. has included this roll forming tutorial. The tutorial is broken out into sections to assist with your use of the material.

Roll forming tutorial sections include:

What Is Roll Forming?

Roll forming is a continuous metal forming process taking sheet, strip, or coiled stock and bending or forming it into shapes of essentially identical cross section by feeding the metal between successive pairs of rolls that increasingly shape it until the desired cross section is completed adding both strength and rigidity to lightweight materials. The process adds both rigidity and strength to the roll formed material. During the roll forming process, only bending occurs. The thickness of the metal is not changed except for a slight thinning of the material at the bend radius.

Roll Forming Techniques

There are two methods commonly used when shaped parts are rolled formed. They are the:

  • precut or cut-to-length roll forming;
  • the post-cut roll forming.

The selection of the best roll forming process is normally based on the difficulty of the cross section and the production length required by the end-user specifications. (CMI uses the post-cut method which provides a higher level of precision to meet our customers’ needs.)

Precut Roll Forming

The material to be roll formed is cut-to-length before being fed into the roll forming machine. Normally, this process includes both a stacking and feeding system that moves the metal blanks into the roll forming machine running at a fixed speed (normally between 50 to 250 feet per minute), and a post production conveying and stacking system. This roll forming technique is typically used for lower volume parts. It is also used when notching can’t be easily handled in a post-cut line.

Tool cost is economical for the pre-cut roll forming process since cutting requires only an end notch die or flat shear die. However, end flare is more obvious and side roll tooling is needed to obtain a high-quality finished shape.

Post-Cut Roll Forming

The most efficient, consistent, and least problematic process is the post-cut roll forming method. It is the most widely used roll forming process and is what is used at Corrugated Metals. The post-cut roll forming process requires:

  • an uncoiler;
  • a roll forming machine;
  • a cutout machine; and
  • a runout table.

Post-cut roll forming can be supplemented by a variety of secondary, or auxiliary, operations including:

  • pre-notching
  • punching
  • embossing
  • marking
  • trimming
  • welding
  • curving
  • die forming

When used in conjunction with post-cut roll forming, these operations can eliminate the need for stand-alone secondary operations providing a complete or net shape profile. The cost of tooling, and the tooling changeover time for post-cut roll forming, are greater than for the precut method, but are usually more than offset by the other advantages. View CMI’s secondary services.

Next: Part 2 of the Roll Forming Tutorial provides an overview of a number of roll forming design issues and a listing of roll forming advantages.

Roll Forming Tutorial Sections