Panels could now be made to very precise dimensions. Many styles of finished profiles could easily be produced, and the length of panels was only limited by handling and transportation restrictions. This process reduced manufacturing costs dramatically.
Today’s roll-forming equipment can operate at speeds up to 600 feet per minute, automatically measure, then cut panels to virtually any length with extreme accuracy
As panel lengths increased, expensive and problematic end-to-end joints were reduced.
This greatly simplified installation and reduced costs, but another problem began to appear. Roof failures due to the thermal effects on such long panels became common.
The attachment of such long panels had to change in order to accommodate these effects. Attachment methods will be discussed in detail later in this manual. (See Chapter 14, Fasteners.)
Most roll-formed panel seams are of the standing seam type
Roll-forming equipment has found its way from the factory to the job site. Today’s metal roof installer may find roll-formers “on-site” in order to quickly make material specific to an individual job. (See Figure 2-9.)
Press-forming of sheet metal uses a piece of equipment commonly called a press brake. This process makes individual metal shingles, tiles, or textured shapes that are not characterized by long panels with parallel lines. Press forming may be used as a standalone process or in addition to roll forming
Press-formed metal panels are often made to resemble their traditional counterparts, such as asphalt shingles, wood shakes, slate, or ceramic tiles. They offer the advantage of lighter weight and simplified installation. Their long life rivals that of actual slate or tile, while maintenance issues are reduced.