Introduction
Roll forming is a metal forming process used extensively in manufacturing industries to produce metal profiles with long lengths and accurate cross-sections. A roll forming machine progressively forms metal sheet or strip into the desired cross-sectional profile by passing it through consecutive sets of rollers or stands. Each stand incrementally bends the profile a little more until the desired shape is obtained. Roll forming is ideal for producing parts with long lengths or in large quantities.
Car panel parts like doors, hoods, trunk lids etc. need to be lightweight yet sturdy. Producing such panels with accurate tolerance using other processes like stamping is difficult and expensive. Roll forming these car body panels ensures dimensional accuracy and reproducibility while saving material and reducing weight. Continued innovation in car panel roll forming technology allows manufacturers to create optimized components faster and more cost-effectively.
Benefits of Roll Forming Car Panels
Roll forming imparts benefits that make it the ideal process for creating automotive body panels.
High Production Speeds
In roll forming the sheet metal moves continuously through the machine at a constant speed. This allows very high production rates. Car panel parts can be mass produced rapidly without the start-stop motion of presses or stamps. Modern roll formers easily achieve speeds over 100m/min.
Accuracy and Consistency
Roll formed parts have excellent dimensional accuracy and consistency. Profiles are formed gradually by controllably bending metal through precision rollers. There is no abrupt shaping as in stamping. This gives repeatable tolerances ±0.5mm for car panels along the entire part length.
Material Savings
Roll forming creates uniform sections using the optimal material required by design. No excess material is used. Steel sheets can be rolled to thinner gauges. This reduces weight and material cost. Car bodies become lighter without compromising strength.
Flexibility
Roll form design software allows creating optimized die shapes easily. Quick die changeover lets manufacturers switch profiles rapidly. Many variants of a panel part can be rolled on the same machine just by changing the roll set. This flexibilty lets automakers customize panels.
Lower Tooling Costs
The tooling required for roll forming like flat roll dies and guides is relatively inexpensive compared to stamping presses and dies. Their simple design and operation reduces maintenance costs. New car panel profiles can be tested and adjusted quickly without needing complete die rebuilds.
Increased Strength
The cold rolling process work hardens the metal giving it higher strength. Car panel parts gain rigidity from the incremental bending under controlled loads. Reinforcing ribs and edge contours can be easily formed for added structural stability.
Evolution of Car Panel Roll Forming Machines
Car panel roll formers have evolved tremendously from their early days to meet the demands of the automotive industry.
Fixed Roll Formers
The first roll forming machines used fixed in-line roller dies. They could produce simple symmetric U-channels and roofing panels. While effective for long uniform parts, fixed roller dies lacked advanced forming capabilities needed for car body panels.
Quick Change Machines
The need to rapidly switch between different profiles saw the development of quick change machines. These used cassette roller boxes that could be swapped out in minutes to roll new shapes. Operators could pre-set cassettes offline enabling faster die changeovers on the production line.
Servo Motor Driven Stands
Early roll formers used gearbox drives that made adjustements difficult. Introducing servo motor drives with advanced controls allowed precisely varying the roller positions in each stand dynamically. This allowed gradually pre-bending and hemming panels along the length for greater forming flexibility.
CAD Simulation Software
Powerful CAD software evolved that could accurately simulate the sequential rolling process. Die design and virtual modelling of the deformation helped optimize shapes digitally before any physical prototyping saving enormous time and costs.
Advanced Materials Handling
Automated unwinding, feeding, righting, cutting and downstream transfer were developed to support faster production speeds, quick die changeovers and just-in-time operation for lean manufacturing. Robotic material handling improved line efficiency.
In-Die Sensing and Correction
In-die sensors and actuators were incorporated for on-the-fly gauge, shape and dimensional monitoring and corrections. This allowed forming high strength steels with thinner and lighter gauges without tearing. The formed profiles stayed within specified tolerances automatically compensating for material variations.
Flexible Manufacturing Systems
Modern flexible roll forming systems integrate production flow with digital process controls. Several forming lines networked using smart controls, rapid dies changes, quick tooling and efficient material handling produce a variety of car body panels just-in-sequence. Operators can switch profiles in minutes to output mixed components together.
Recent Innovations Furthering Car Panel Roll Forming
Continual technology innovation in roll forming machines, tooling and automation are enabling manufacturers to create lighter and stronger car panels faster.
Roller-panel Interaction Analysis
New simulation capabilities using FEA and AI deep learning accurately model roller deformation interactions with the metal panel during bending. This allows optimizing roller shapes, precise positioning and dynamic adaptive adjustments for forming complex panel geometries like critical radii and tight flanges.
Variable Angle Roller Stands
Actuator controlled roller boxes that can dynamically vary the angle between consecutive roller stands are enabling greater forming flexibility and shape complexity. Sensory feedback loops continuously adapt roller angles and die shapes during production allowing forming stronger HSS grades into intricate shapes.
Roll-Bending-Stamping Integration
Hybrid machines combining roll forming with stamping and bending operations in one flow are improving feature forming and reducing secondary processing. Efficient integration of stretching, press braking, piercing and hemming with the rolling process allows considerable material and operational savings.
Hydroforming Rollers
Incorporating fluidic hydroforming principles into roller die contouring further improves formability allowing more panel shape control. Pressurized fluid helps avoid cracking and tearing by providing localized outward support to metal sheets when bent over highly contoured rollers.
Roll-Bonding Dissimilar Materials
Joining dissimilar metals like aluminium and steel into one sandwich blank before roll forming allows creating hybrid panels with optimum properties. The lighter outer layers reduce weight while the stronger core provides structural stability. Roll-bonding integrates material strengths in one process.
Roll Forming Press Hardened Steel
Roll forming steel grades immediately after inline press hardening imparts extremely high strengths (over 1500MPa). This allows creating structural panels that meet crash performance while minimizing thickness and weight. It eliminates the need for subsequent heat treatment.
Roll Forming Aluminium Alloy Sheets
Adapting roll forming for aluminium sheets using edge conditioning, thermal management and specialty coatings on roll dies is enabling lighter panels for EVs. Optimized low frictionTooling reduces cracking and tearing when forming thin, high strength aluminium alloy grades into complex shapes.
Benefits of Innovation in Car Panel Roll Forming
The tremendous technology progress made in roll forming machines and processing over past decades has imparted significant benefits to automotive manufacturing.
Greatly Expanded Forming Capabilities
With innovation, roll forming has transformed from being able to create only simple symmetrical shapes to now form the most complex body panel geometries while controlling tolerances. Manufacturers can replace stamped panels with roll formed parts.
Ability to Form New Materials
Innovation has enabled roll forming a much wider range of materials beyond mild steel. UHSS grades, aluminum sheets, tailored blanks and composites can now be reliably roll formed into car panels. Parts can be lightweighted for fuel efficiency.
Lower Forming Costs
Innovations like rapid die change systems, advanced process simulation, adaptive forming and automation significantly reduce overall equipment and operational costs for roll formed panels compared to stamping or other methods.
Environmentally Clean Process
Roll forming is a cold forming process with no heating or cooling needed. It uses no oils or lubricants. Scrap generation is minimal. Energy consumption is very low compared to stamping. It is an environment friendly metal working process.
Safer Automobiles
Car panels produced using the latest roll forming methods and materials provide greater impact strength. Lighter panels reduce overall vehicle weight improving braking, handling and control. Increased use of roll formed panels will lead to safer cars.
Higher Production Volumes
With ultra high operating speeds and quick die changeover, innovative roll forming systems can mass produce panels rapidly to meet rising production demand. Just-in-time supply to assembly lines becomes feasible.
Future Possibilities in Car Panel Roll Forming
Many exciting possibilities are opening up to make roll forming the dominant process for producing automotive body panels in the future.
Adaptable Flexible Machines
Next generation flexible machines with completely reconfigurable roller die modules will enable producing multiple panel variants on the same system just by software controls. Rapid material and die changeover will adapt small-batch production runs.
Increased Aluminium Usage
Improved roll forming technology will enable extensively using aluminium alloys to manufacture lighter car doors, hoods, liftgates and roof panels. Affordability and recyclability makes aluminium an ideal material for high volume roll forming.
Roll Formed Hybrid Structures
Combining steel, aluminum and composites like carbon fiber into hybrid sandwich structures will yield very strong yet lightweight panels. The different materials can be continuously joined and roll formed in one process.
Integrated Manufacturing Lines
Fully automated roll forming lines integrated with body-in-white production can transform panel supply from batch processing to a synchronous sequence. Mixed panels can be delivered just-in-sequence to the assembly stations and welded together without work-in-progress inventory.
Roll Forming Larger Sections
With advanced forming techniques and quality servo motors, roll forming will achieve wider profiles and larger car body parts. Doors, liftgates and side panels may become integrated monolithic structures. This will simplify framing and reduce chassis weight.
Environmentally Sustainable Production
Innovations will help make roll forming even more energy efficient with tighter loop process control and near zero scrap generation. Combined with wider use of green materials like recyclable aluminum and plant-based composites, it will become a highly eco-friendly manufacturing process.
Challenges to Further Innovation
While roll forming car panels holds tremendous promise and potential, some technology gaps need to be bridged through continued innovation.
High Development Costs
Designing and building new innovative roll forming machines and dies for testing involves very high costs and lead times. Obtaining funding for development without proven large volume demand is difficult. Partnerships between industry and academia can spur innovation. Government support to share development costs will also help offset risks.
New Steel Grades Limitations
Emerging AHSS grades offer ultra-high strengths but have poor formability. They require special tooling and very high precision when roll forming to avoid cracking and tearing. Cost-effective ways to produce these materials in high volumes must be developed.
Material Springback Control
The latest high strength materials tend to springback excessively after rolling. New methods to accurately compensate for springback using nonlinear adaptive control will be needed to form parts within tighter tolerances.
Process Modeling Challenges
Accurate modeling and simulation of the roll forming process remains difficult due to its sequential multi-stage continuous nature and number of interactive variables. More computing power and AI assisted modeling is needed to digitally duplicate the process prior to production trials.
Secondary Processing Needs
Many panels still require downstream press forming, flanging, piercing, trimming, and assembly after roll forming. Innovations in operations integration and automation will be needed to realize the true potential of roll formed one-piece body structures.
Industry Mindset Shift
Switching existing stamping production lines over to roll forming requires considerable rebuild costs and process change management. The automobile industry needs more proof and visibility of roll forming benefits before large scale adoption occurs. Demonstration sites, pilot projects and training programs will help drive the transformation.
Conclusion
The many benefits of roll forming make it the ideal process choice for mass producing lightweight automotive body panels with accuracy and repeatable quality at high volumes. The technology has rapidly evolved over past decades through continued innovation to meet the needs of the automotive industry.
With advanced machines, tooling and capabilities now available, roll forming is ready to take on a bigger role in car panel manufacturing. Ongoing innovation to incorporate new materials, integrate automation and implement process improvements will drive further adoption across the industry. Roll formed car body structures will become commonplace in future automobile production. Exciting possibilities lie ahead as innovation propels roll forming car panels to new frontiers.
FAQs
What are the key innovations enabling roll forming of car body panels?
Some important innovations are high speed servo motor drives, rapid die change systems, advanced simulation software, in-die monitoring and adaptive control, and integrated automation with stamping and bending in one production flow.
How will roll forming help make cars more sustainable?
Roll forming is energy efficient, minimizes scrap material, and enables light-weighting for fuel efficiency. Increased use of aluminum and optimized material usage will reduce environmental impact.
What materials are commonly roll formed into automotive panels?
Mild steels, high-strength steels, aluminum alloys, tailored blanks, composites and sandwich panels combining different metals can be roll formed into lightweight high strength panels.
How do roll formed car panels compare to stamped panels?
Roll formed panels offer higher dimensional accuracy, repeatability and strength compared to stamped panels along with lower production costs. Complex panel shapes can be reliably roll formed.
What recent innovations show the most promise for the future?
Machines with completely flexible and reconfigurable roller dies, integrated roll-stamping lines, hydroforming rollers and roll forming aluminum and tailored blanks have enormous future potential.
What needs to happen for wider industry adoption of roll forming?
Lowering development costs, producing advanced steels economically, implementing process improvements and training programs will help manufacturers recognize the benefits leading to fuller adoption.
How will car bodies be different in future due to roll forming innovations?
With monolithic roll formed panels, car bodies will be lighter, safer, more dimensionally accurate, and more sustainable. Hybrid materials and one-piece structures will simplify construction.