Common Problems with Rollforming Machines - Part 1

By New Tech Machinery.

Oil canning definition, causes and preventative measures.

It’s common for a contractor to experience a problem with a certain product or piece of machinery, including a portable roof panel rollforming machine.  New Tech Machinery (NTM) has manufactured rollforming equipment for more than 28 years and has helped our customers with any machine issues that arise. Many of these rollformer problems are common and can be remedied easily by making slight adjustments or proper maintenance.

Our service department experts at NTM have seen everything that could go wrong with a rollforming machine and want to educate the industry on the common roof panel machine problems.  In this four part article, NTM highlights four of the most common rollformer problems and provides remedies for each one. The four problems covered in this article series are:

• Oil canning

• Panel curvature

• Shear misalignment

• Markings/scratches transferring onto panels

Problem #1 - Oil Canning

What is Oil Canning?

According to the Metal Construction Association, “Oil canning can be defined as visible waviness in the flat areas of metal roofing and wall panels.  In technical terms, oil canning is referred to as elastic buckling (more commonly known as ‘stress wrinkling’).”

Oil canning is a common occurrence in cold-rolled, light-gauge flat metal products, so if you see panels with noticeable waves between the seams, you’re most likely looking at oil canning.  Luckily, in most cases, oil canning is simply a cosmetic issue that doesn’t diminish the integrity of a roof or wall system. However, most people consider it unsightly and try to avoid it if possible.

Why Does Oil Canning Happen?

Oil canning is a complex phenomenon that is not only difficult to measure, but also difficult to determine the source of since it has numerous causes that could come into play.  One of the most prominent reasons metal warps to form oil canning is due to the fact that metal inherently wants to return to its original shape. So when it’s getting processed and rollformed, the metal takes on a new form but may attempt to revert back to how it was before.  Such movement can form the wavy bumpiness characteristic of oil canning.

The majority of oil canning instances are caused by:

• Manufacturing stress on the metal

• Rollforming and slitting pressure inflicted on the metal

• Unaligned panel installation

• Inaccurate or irregular movement of panels

• Lack of thermal movement space

• Incorrect installation of accessories (clips and fasteners)

• Installing on an uneven substrate

How to Fix Oil Canning

Once oil canning works its way into a panel, there isn’t a way to fix or get rid of the waviness.  But there are some preventative measures that you can take to avoid the possibility, including:

• Choosing a lower gloss finish

• Ensuring the roof deck is even

• Use tension-leveled metal

• Put backer rods underneath the panels

As it applies to a portable roof panel roll forming machine, there are a couple of different ways to correct some of the oil canning; most of which involve putting some type of structure into the flat area of the panel.

Typically structure ribs include:

• Clip relief (a standard in all NTM roof panel profiles)

• Bead ribs

• Pencil ribs

• V-ribs

• Striations

• Corrugations

Make sure to check back next week for part 2 covering panel curvature.

Learn more about New Tech Machinery.