How a Sheet Metal Roll Former Can Create Standing Seam Roofs
Sheet metal roll forming takes standard sheet metal and forms it into precise components for use in construction. This powerful process can create a variety of different profiles, including standing seam roofs.
There are many considerations when designing a custom roll form line. These include lubrication, labor content, and tolerances.
Choosing the Right Machine
When choosing the right machine for your business, it is important to consider several factors. These include the size of the desired part, the material to be used, and the forming capabilities of the machine. Additionally, it is crucial to select a manufacturer with a good reputation and a solid warranty package.
A reputable manufacturer should offer comprehensive after-sales support, maintenance services, and spare parts availability. A knowledgeable support team will be able to address any problems quickly and ensure that your machine operates at peak efficiency.
Roll forming equipment is highly automated, reducing labor content and the possibility of human error. Additionally, roll forming can produce complex sheet metal roll former profiles that cannot be produced through other forming methods.
Depending on the size of the machine, the number of forming points, and the maximum strip width, the machine can be designed to produce a range of different part shapes. Some machines have quick-change tooling that enables a more flexible setup for different profile requirements. Alternatively, some manufacturers can use a rafted line system to enable faster changeovers.
Preparing the Coil
Often, metal coils become distorted while in storage. This distortion makes the coil prone to a variety of defects.
When a new coil is uncoiled, it must undergo some type of shape correction before being fed into the roll forming machine. A straightener or a precision leveler is commonly used to accomplish this task. Both use a series of work rolls to alternately stretch and compress the upper and lower surfaces. This deformation also relieves residual stresses within the coil.
This process is important because it ensures that the coil will feed properly through the machine. It also eliminates problems like center buckle and crossbow, which are caused by excessive coil bending force.
These defects can affect the appearance of the finished product and reduce the functionality of the metal part. A good quality leveler can eliminate these defects and prevent them from reoccurring. This eliminates the need for secondary processing and saves money.
Feeding the Coil
A sheet metal roll former takes flat, unformed steel or non-ferrous coil material and creates a formed component from it. The process requires no heat, so the metal retains its physical properties. On-site equipment allows fabricators to create components on the spot, minimizing costs by eliminating shipping and storage.
The level of efficiency a metal fabrication operation achieves depends on how much time is spent changing out coils and how frequently the machine shuts down for those changeovers. Many operations use lean manufacturing practices to reduce inventory and keep only what they need on hand at any given time. This means a production line may stop several times a shift to swap out one color of panel for another.
A single-mandrel decoiler has a high labor content because each time a change is needed, the entire line stops and someone uses a fork truck or overhead crane with a J hook to remove the old coil from its holding place, expands the coil, cuts it, retrieves a new coil, and rewinds it onto the mandrel of the decoiler. Higher levels of automation allow operators to stage coils while the line is running and eliminate most of that manual storing, transporting, cutting, and feeding.
Changing the Coil
Roll forming can produce complex geometric shapes with tighter tolerances than other metal fabrication techniques. It can also create a finished product without the need for secondary processes, which saves time and money and helps ensure consistent results.
Historically, many companies kept a wide variety of prepainted panel stock on hand to accommodate short runs. Today’s lean mindset has changed the landscape, with companies embracing just-in-time thinking and producing only what customers order. This has resulted in a lot of coil changes for roll forming operations.
Changing out a coil takes between four and 12 hours of machine uptime while the tooling is changed out. To minimize downtime and make the process more efficient, some u channel roll forming machine fabricators install an accumulator to hold a portion of the coil while it is being changed out. This can save 10 to 15 minutes per coil change and eliminate the need for a shear welder, which further reduces downtime. Many shops also choose to post-cut the strip after it comes off of the accumulator, which further cuts down on the amount of time spent handling each piece of material.
Forming the Part
While each roll forming manufacturer will have its own process, they all have the same basic steps. They start with a coil of sheet metal that can range from 1 inch to 30 inches wide and 0.012 to 0.2 inches thick. The coil is fed into a series of forming stations to transform it into the desired part geometry.
Each station will cause the strip to bend and fold a little more, and each pass requires the tool steel rolls to be properly calibrated. This will ensure that the flanges, lips, and bends come out where they are supposed to be.
Roll forming is very efficient, which makes it the preferred production method for many of today’s parts. But the process does induce stresses into the part that can lead to distortions, including end flare.
The solution for preventing end flare is to use antiflare units that overbend the leading and trailing edges of the workpiece. This will also help with other idiosyncracies of the process, such as crossbow and dishing. These distortions typically occur as a result of upstream processes or material issues, such as mill coils with edge wave or slitted coils that have random camber in the outer stand.