Modern hydraulic systems are transforming metal forming processes, delivering unmatched precision, energy efficiency, and cost-effectiveness.
Contributed by Jens Schmitt, Presses Application Manager, Bosch Rexroth
Automotive manufacturing is consistently evolving to meet market demands as new products and parts are innovated. Hydraulic systems remain a major player in creating these components with heightened precision, quality and efficiency, specifically in the metal forming stamping process. For essential car body parts like door panels, fenders, roofs, complete car side panels and hoods, the stamping process is used to form these shapes through the supporting role of a hydraulic-equipped and controlled cushion system to reliably form quality parts within the lead press.
Hydraulics are used extensively throughout automotive press systems, to form shapes for car doors, panels, roofs, hoods and more.
A record number of people are driving in the U.S., up 2.1% in miles traveled since pre-COVID-19 levels, and investment in the electric vehicle (ev) industry is consistently driving innovation. These factors present manufacturers with an opportunity to build efficient and dependable vehicles that not only keep manufacturing costs low but also maintain quality and safety for consumers.
The metal forming process
Metal stamping automotive body parts is a process that has been streamlined by using hydraulic components for decades. To meet the rising manufacturing demands of today’s markets, hydraulic systems have continued to evolve into more precise and automated processes. The solutions used in metal forming are proving to be more dependable than ever — especially with modern software upgrades — as major car manufacturers worldwide use hydraulics systems for quality control and the prevention of body part defects. To achieve zero defects, process parameters must remain consistently equal with each stroke. The high stroke rates and large part quantities demand high pressing speeds and can only be achieved through press impact force with an actively controlled cushion system, ensuring precise force control and accuracy during the forming process.
The sheet metal stamping process is made up of multiple presses arranged side by side in a row with electromechanical automation continuously moving parts from one press to another. Each of these presses can complete a different operation on the parts including forming, trimming, piercing, and bending. The lead press, which completes the largest forming operation on the sheet metal into its general part shape, is often equipped with a hydraulic cushion system. These cushions provide a counterforce on the sheet metal to help prevent any tearing or wrinkling during the forming process. Hydraulic cushion systems offer superior power and control within this process, but there are still challenges inherent with implementing hydraulics in automotive manufacturing.
The stamping process uses hydraulic systems in automotive manufacturing to create car body parts with controlled precision.
One complexity in this process lies in the continual, dynamic motion of the press, which requires precise force application and pressure adaptation to perfectly shape the raw material repeatedly. A valuable feature of modern systems is the force adaptation function, allowing self-learning of the cushion to guarantee accurate optimization of the cushion function — without human interference — for the complete production batch. Specifically, precise timing is also of utmost importance to not hit the material too early or too late. The precision that hydraulic components offer to the shaping of materials in metal stamping helps curate more control — a feat that pneumatic and mechanical systems are less successful at.
The more complex electromechanical cushion system solutions are considered less standard in the United States automotive manufacturing industry due to additional moving parts requiring extensive maintenance. There is a growing recognition and adoption of hydraulic systems in the industry due to controllability and modern exigency for energy saving options, so much so that newer presses are now being designed with these components as default.
Modernization of automotive manufacturing processes
The automotive manufacturing industry is moving toward advanced, energy-saving solutions to modernize legacy systems and streamline the stamping process. As with many industries, automotive manufacturers value tradition and conventional machines and methods. Overcoming this traditional mindset to move toward advanced solutions can be difficult.
Hydraulic cushion systems in the lead press help produce superior power and control throughout the forming operation.
Although retrofits of cushion systems are less common as new presses enter the market, some manufacturers are maintaining their legacy equipment in hopes of not disrupting their operations and to increase the press equipment’s life expectancy, all with modern demand and investment consideration. Due to this hesitancy, there is an opportunity to integrate and retrofit new technologies. A key argument for doing so is that retrofitting complete hydraulic systems into existing infrastructure can help companies balance demand and combat maintenance costs while still being able to reap the benefits of an optimized control.
Relying on legacy systems can lead to higher energy consumption due to the wear on the hydraulic parts. Leaks can impact the force of the system, making the hydraulic equipment much less efficient. Retrofitting outdated components in metal stamping heavily impacts the output quality and ultimately leads to higher productivity from the machine, increased cost-effectiveness, and greater precision.
Moving the industry forward
Discussions between automotive manufacturers regarding the advancement of research and development for new solutions are promising. Technology that accommodates system functions should be welcomed, but with a clear understanding of how the industry continues to change.
Some large equipment manufacturers are moving the needle on what could soon be considered industry standard. They are using less widely adopted strategies, like deploying direct drive hydraulic solutions where the pump acts as a hydraulic motor, generating energy that can be fed back into the grid. Additionally, total hydraulic system designs can be more energy efficient with a focus on reducing heat generation and power consumption compared to exclusively standard throttling-based approaches. A mixed system throttling for precise dynamic control combined with a direct hydraulic motor for energy recuperation achieves dynamic precision and energy savings. Other solutions can be too harsh on equipment, leading to increased wear, and higher maintenance costs.
Energy efficiency is another driving point for conversations about growth and expansion in the metal forming industry. The stamping process generates substantial energy through the cushion function, which is typically anticipated as heat removal. The industry is looking into ways to recapture this energy and transfer it back into the process, aiming to reduce energy consumption, lower operation costs and more. Finding the right balance between efficient and innovative processes that produce quality throughput will be a priority on both sides of the industry moving forward.
Advancements in energy savings, streamlining hydraulic cushion systems and retrofitting legacy machinery are all essential parts to improving and developing the most efficient metal forming operation. If equipment manufacturers continue engaging in conversations with automotive manufacturers, hydraulic solutions can be optimized to meet the evolving demands of the industry. Evaluating total process parameters and condition of equipment is enhanced with diagnostic capabilities that can ultimately show the total cost of ownership of up-to-date hydraulic cushion systems.
Bosch Rexroth
boschrexroth.com
Filed Under: Engineering Basics, Technologies, Trending
