Roll formed parts are metal products shaped by a series of rollers, during the process known as roll forming. Most metals can be roll formed, but the most commonly roll formed metals are brass, steel, zinc, aluminum and zirconium.
Roll formed parts are valued for many reasons, among them uniformity, accuracy, structural integrity and low tooling costs. They serve a myriad of industries, such as: building construction and architecture, carpentry, commercial automotives and home improvement. They’re also used to fabricate a wide variety of commercial, consumer and industrial products.
Examples of common roll formed products for carpentry and building construction include: angle irons, aluminum angles, steel angles, metal channels and metal trim. Angles are designed to provide support in two directions, and frequently feature slots or holes for connecting parts.
Similarly, metal channels act as a support system to rails and frames, and metal trim fits around the edges of a part or product. Both metal channels and trim are additionally used for consumer, industrial and commercial products. In the industrial and commercial worlds, roll formed metal wall panels can protect factory walls from sparks, debris and the like, or they can alter the appearance of office building walls.
With applications in nearly all industries, metal rings, which are simply circular parts, serve many purposes, such as shielding elevator buttons, embellishing telephone buttons, adorning clothing, ensuring street signs stay upright, securing lock hardware in doors and preventing hoses from disconnecting. Roll formed products may also be custom made for specialty applications, like bus industry seat tracks.
Roll forming is a cold forming process, meaning that it does not require heat to make metals pliable. Rather, force and compression shape the metal, and the compressive stress created by the rollers gives roll formed parts qualities of strength and durability. At the beginning of the roll forming process, a stock or custom form of metal is delivered into a first set of rollers, which are designed to fit snugly around the formed metal contours.
It is then forced into a series of subsequent rollers, each holding a slightly different position in order to gradually shape it. There are a few different roll forming processes, the most common of which are post-cut rolling forming and pre-cut roll forming. Post-cut roll forming uses continuous metal rolls, which are not cut to size until after the piece has been roll-formed. Post-cut forming is considered efficient, consistent and the least problematic roll forming process. Thus, it is most common.
Pre-cut roll forming, which is mostly used for low-volume runs, instead uses metal that has been to length before it enters the roll forming machine. Because roll forming is a modular process, roll formers can be configured and reconfigured to create all kinds of metal shapes, although it cannot create sealed ring products, because that requires secondary processing; ring products must be welded or connected with fasteners in order to become sealed. Roll forming machines may, however, come equipped with punching capabilities and other reduction elements.
The only notable drawback of roll forming is that it is fairly labor intensive and requires a trained specialist to to properly set roller systems. While CNC machining systems are slowly being integrated into these processes, it can still be somewhat expensive. However, its many benefits outweigh this drawback for many manufacturers.
Aside from its modularity and its ability to form metal without heat, there are a number of reasons to want to invest in roll forming or in roll formed parts. First, because it creates very little scrap and use very little energy, making roll formed parts is very cost-effective and profitable. Most roll formers can use nearly 94% of the material original fed into them.
Also contributing to the cost-effective nature of roll forming is its second advantage, its ability to continually produce parts and complete high volume orders. In addition, the possibilities associated with rolled formed parts are broad and nearly endless; rollers can be coated with non-reactive powders or oils that will not affect surface properties.
This means that roll formed parts can be successfully coated, polished, finished, cured and otherwise treated. Finally, no matter the exact nature of a roll formed part, a manufacturer or customer can rest assured that, thanks to the compressive stress that made it, it will prove itself to be strong and durable.