Knowing more about the Roll Forming Process

Although different manufacturers have their own unique set of steps for their forming process that is proprietary to them, there are fundamental procedures common for the roll forming process.

The process begins from a large coil of sheet metal with dimensions: 1 inch to 30 inches wide with a thickness of 0.012 inches to 0.2 inches. The typical process starts and ends with the feeding of the coil to the cutoff and discharge. Below is a comprehensive description of each step:

⒈Uncoiling Stage:

Metal coils tend to retain their coiled form and become distorted. To correct this issue, the coil will be loaded onto a decoiler machine and fed through a flattener to remove the coil set. The lead end is cleanly trimmed to allow smooth feeding into the pre-press machine. Tapering the beginning of the feed coil will make it easier for the sheet to slide into the forming rollers.

⒉Pre-pressing Processes

The metal sheet may pass into primary processes before being fed into the roll forming rollers. These may involve adding features like holes, slits, and slots.

⒊Roll forming Stage:

The material is progressively shaped at this point. A usual roll-forming machine with 10 to 24 pairs of roller die stands to aid in the process. The machine's mechanism can be either driven individually or collectively to force the ribbon of metal through the rollers. This procedure will result in the gradual shaping of the metal to the desired shape.

⒋Cutoff and Discharge Phase

To increase the production process's efficiency and speed, parts will be cut to length while they are in motion. Once they are cut to the desired length, they will be discharged to and prepared for further processing or shipment.

⒌Secondary Processes

There are many options for secondary processes depending on the intended use of the rolled metal. Some processes are pre-integrated wherein additional features will be added as the part comes off the cutoff, and others may be needed to be performed at another station.

● Below are some examples of the secondary processes done in a roll-formed metal sheet:

Adding other components

Notching

Punching

Tight tolerance forming

Straightening

Minor assembly

Plasma Cutting

Stamping

● Importance of Lubrication in the Roll Forming Process

Like any metal forming process, friction is always a factor that should not be overlooked. Friction is defined as the resistance produced when two bodies are in contact, and for the rolling process, this might cause a rise in temperature where these surfaces meet. Adding to this, the temperature is further increased by the speed of the process. In order to address the issue of overheating, it is preferred to use lubrication in the roll forming process. This is because it reduces the friction between the rolls and the metal to prevent tool wear. 

While lubrication is essential,  this should not be overly applied beyond the maximum allowable amount. Friction is still necessary for driving the metal forwards the rollers. It is critical to note that friction should not be eliminated or reduced below an appropriate level.

Roll forming uses fluid lubricants with a low viscosity rating -an example is paraffin for non-ferrous metals such as aluminum and copper. The amount of lubricant application will depend on the thickness of the material, the number of roll stations, and the bending amount.