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. (Corrugated Metals uses the post-cut method which provides a higher level of precision to meet our customers’ needs.)
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.
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:
- 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.