Functions of Purlin Roll Forming Machine

A purlin roll forming machine is an essential equipment used in the manufacturing of purlins. Purlins are zed or c shaped members which are used to support roofing sheets in industrial, commercial and residential buildings. They provide support to roof sheets against wind uplift and transfer the loads to main rafters and walls. Purlins allow roofing sheets to be fixed on top, thereby providing a continuous surface for the roofing.

The purlin roll forming machine forms the plain metal strips or coils into the desired zed or c shaped sections by passing them sequentially through a series of roller dies. The formed sections have a higher load bearing capacity than the plain sheets due to the stiffened flanges. Roll forming allows mass production of purlins with accuracy and superior quality. Based on their features and functionality, purlin roll forming machines can be classified into the following types:

purlin roll forming machine
Functions of Purlin Roll Forming Machine 4

Types of Purlin Roll Forming Machines

C and Z Purlin Roll Forming Machines

The C and Z purlin roll forming machines are used to form C and Z sections respectively from metal strips. They form the most common and widely used types of purlins due to their high load bearing capacity and compatibility with all kinds of roofing systems.

Double Layer Roll Forming Machines

These machines are designed to form purlins with two layers of metal strips. The two strips are overlapped and roll formed together longitudinally to produce purlin sections with higher load bearing capacity.

Built-up Purlin Roll Forming Machines

In built-up purlin roll forming, two or more roll formed C or Z sections are integrated side by side longitudinally to form heavier and stronger built-up purlins. These machines have added assembly stations to join the sections.

Standing Seam Purlin Roll Forming Machine

These machines produce interlocking purlins that can be joined together easily on site to provide a continuous sheet supporting system. The interlocks allow longitudinal expansion and contraction of the roof.

Multi-Profile Purlin Roll Forming Machine

As the name suggests, these machines can produce multiple profiles of purlins by changing the roller dies. They provide flexibility to manufacture different purlin sections on the same machine.

Gutter Roll Forming Machines

Gutter roll forming machines are designed specifically to produce eaves gutter sections which collect and drain off the rain water from roofing.

Main Parts of a Purlin Roll Forming Machine

A purlin roll forming machine consists of the following main parts:


This unwinds and feeds the plain metal coil strip into the forming section. It maintains consistent and non-stop feeding of the material for continuous production.

Forming Section

This comprises of a series of rolling stations with roller dies that progressively bend and form the strip into the desired purlin section as it moves sequentially from one station to the next.

Hydraulic System

It provides the power and motion for the movement of roller dies to apply bending and forming on the strips.

Control Panel

The PLC based control panel gives centralized control of different parameters and operations of the machine.

Cutting Unit

Once formed, the continuous purlin sections are cut into desired lengths as per requirements using rotary or shear cutting.

Exit Conveyor

Transports the cut and formed purlin pieces out of the machine.

purlin roll forming machine
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Main Functions of a Purlin Roll Forming Machine

The major functions of a purlin roll forming machine are:


  • Feeds the plain metal coil strip into the forming section in a controlled manner.
  • Maintains proper tension and alignment of the moving strip.
  • Prevents jamming, slipping or tearing of the strip during feeding.

Bending and Forming

  • Performs accurate and smooth bending at multiple stages through the roller dies to shape the strip into desired purlin profile.
  • Achieves high quality forming without defects like wrinkling, splitting or cracking of the metal.
  • Allows changeover to different profiles by replacing the roller dies.

Punching and Embossing

  • Creates holes or embossments on the purlin webs as per design needs for fixing roof sheets.
  • Achieves punching/embossing in synchronization with the strip movement without disrupting production.


  • Cuts the continuously formed sections into fixed lengths as required by the customer.
  • Ensures dimensional accuracy of the cut lengths.
  • Allows hassle-free offloading of the cut pieces for further processes or dispatch.

Speed Control and Monitoring

  • Maintains precise control on the line speed for quality output.
  • Prevents overload, jams or defects by monitoring the machine operations.
  • Enables making speed adjustments through the control panel.

Safety Functions

  • Immediately stops the machine if overload, faults or unsafe conditions are detected.
  • Prevents accidents and protects workers as well as the machine.
  • Resumes production automatically when safe conditions are restored.

Parameters to Consider When Selecting a Purlin Roll Forming Machine

The selection of an appropriate purlin roll forming machine majorly depends on the following parameters:

  • Type and size of purlin sections to be produced
  • Metal thickness and properties like tensile strength that will be handled
  • Production speed, output capacity needed
  • Level of automation and control required
  • Available space for machine installation
  • Additional functionalities needed like punching, stamping etc.
  • Budget constraints of the customer
  • Availability of spares, service support from machine manufacturer etc.

The machine manufacturers usually offer customization options to tailor the machine as per customer’s production needs. A detailed discussion of requirements with the manufacturer is recommended for selection of the optimal machine configuration.

Major Benefits of Using Purlin Roll Forming Machines

Some of the major benefits offered by purlin roll forming machines are:

  • High production capacity and output up to 18-20 meters per minute.
  • Ability to handle thin to thick coils of width up to 1250 mm for wider purlins.
  • Superior and consistent quality of formed sections.
  • Minimal material waste generation.
  • Lower production costs compared to manual methods.
  • Flexibility to produce different shapes and sizes.
  • Low maintenance requirements due to sturdy construction.
  • High operational safety for workers.
  • Long and trouble-free service life of over 5 years.
  • Made with advanced technology for precision and reliability.

Applications of Purlins produced by Roll Forming Machines

The purlin sections produced using roll forming find applications in:

  • Industrial buildings, warehouses, factories etc.
  • Commercial establishments like shopping malls, airport hangars etc.
  • High rise apartments, villas, residential complexes.
  • Agricultural sheds, cold storages.
  • Sports stadiums, exhibition venues etc.
  • Infrastructure projects like metro railways.

Purlins created by roll forming provide complete roof framing solution as they are compatible with all kinds of roofing like metal sheets, polycarbonate, sandwich panels etc.

purlin roll forming machine
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Q1. What materials can be used to manufacture purlins by roll forming?

Common materials used for purlin production are low carbon steels like galvanized iron or Zincalume steel strips, stainless steel and aluminum. The rolls must have requisite thickness, width and material properties suitable for the purlin design.

Q2. How to control the quality of purlins produced from roll forming?

The quality of formed purlins depends on precision of roller dies, proper machine setting and roll forming process parameters. Strict adherence to quality checks, proper gauging and monitoring, finished product inspection also help ensure quality control. Proper maintenance and operation by skilled manpower minimizes defects.

Q3. What safety measures are required during operation of purlin roll forming machines?

Safety measures include proper machine guarding, emergency stop buttons, ensuring correct material feeding angle and speed, use of protective gear by workers, restricting access during running machine, training workers about safe working practices etc.

Q4. How much area is required to install a purlin roll forming machine?

The machine size and layout determine the space needs. Typically about 20-25 feet width is needed for the forming line itself. Additionally, space is required for safe movement around machine, material loading and unloading, and finished products storage.

Q5. What is the typical production capacity of purlin roll forming machines?

Production capacity depends on machine speed, purlin size and other factors. On average, a machine may form around 600-1000 meters of purlins per shift of 8 hours. Capacities of up to 2000 meters per shift are also possible for high speed machines.

Q6. What maintenance is required for purlin roll forming machines?

Main maintenance includes periodic lubrication of bearings, gear boxes and chains, checking alignments, changing worn out components like dies and punches, observing leaks and fixing hydraulic issues, oiling and cleaning moving parts etc. This minimizes breakdowns and ensures smooth functioning.

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