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Roll Forming Glossary

Metal roofing and roll forming are important and common operations in the construction, architecture, and residential building industries.

cold roll orming machine

This comprehensive guide helps simplify the complicated jargon and processes often used in metal roofing and roll forming and collects it all in one glossary for you to refer to in a pinch. We’ve included definitions for:


Hemming in metal forming describes where the material is folded back on itself.


A worker who fabricates, assembles, or repairs machinery; a craftsman skilled in the use of machine tools; one who operates a machine, an individual whose role involves assembly, fabrication, operation, or machinery repairs.

Metal coil

Metal coils are sheets of the metal wound into a tight loop to help transport them using minimal space, coils are the most efficient way to transport or store sheet metal.

Metal roll forming

The process of feeding metal, finished, coiled, flat, or otherwise, through a series of rollers where each roller station further manipulates the piece of metal into the desired shape.


A manual or computer-operated (usually computer-operated) device that prompts the metal roll forming machine to function in the way it has been instructed and follow the input measurements and preferences.

Drive rollers

Drive rollers are the parts that move the metal through the roll forming machine, typically made of metal or polyurethane.

Forming rollers

Forming rollers are where individual metal parts are bent into a specific shape or form, the metal passes through to bend or form the desired shape.

Hydraulic tanks

They aren’t standard on all roll forming machines, but they are commonly added to make the machine faster for higher production or to automate the shears.

Power source

How the roll former is powered and able to run; usually electric or gas.

Forming stations

The spots at which the metal is bent or manipulated by a pair of forming rollers.

Shear or guillotine

The shear or guillotine is the part of the cold roll forming machine that cuts the metal part or component at a specified length.

Post-cut shear

A post-cut shear describes a roll-formed product that is first formed and then cut to a specific length or size afterward.

Pre-cut shear

Metal is cut at the entry end of the machine before it goes through the forming stations: a roll-formed product that is cut into a specific length or size before going into the forming stations.

Metal sheet

Metal is formed into thin sheets by a rolling process.


Cutting different shapes out of sheet metal from the edge of a blank strip to prepare a panel for installation.

Portable roll forming machine

A condensed, transportable piece of machining equipment, it takes everything a metal roll former does but in a smaller size so it can be transported easily, and used to roll forming metal sheets/coils into the metal roof or wall panels. A portable roll former can be powered by gas or electricity, and often comes with an attached or stand-alone de-coiler for the metal and run-out tables for finished panels.

portable seamless gutter machine

A portable seamless gutter machine is a smaller, condensed, transportable machine used to roll form seamless gutters (from metal sheets/coils) directly at a job site.

Portable roll forming machine

A portable roll forming machine is a metal roll former that is smaller in size and can be transported from place to place. Usually powered by gas or electricity.

Portable roof panel machine

A portable roof panel machine is a compact and easily transported machine that cuts metal coils into the metal roof or wall panels.

Run-out table

An adjustable height platform is used to support and keep roofing panels level as they exit the roll forming machine. Typically supplied in 10’ (3m) lengths.


Slitting is cutting metal sheeting into narrower strips.


Tapering is narrowing the metal panel at one end.

Read More: Roll Forming Process: Basics, 7 Applications, 5 Types, Top 11 Design Guide

Works Cited: Metal Roofing & Rollforming Glossary: A Guide to Industry Terms You Need to Know (