Manually operated press brakes are among the more labor intensive operations in any fab shop that uses them. The Robotically Integrated Bending Solution (RIBS) system integrates robotic automation with specialized software to yield more efficient bending operations.

Automated press brake with parts ready for bending.

The robot first places the part into a qualifier to ensure the part will be positioned correctly in the press brake.

The robot lines up the part in the press brake for proper placement before bending.

The robot is programmed to follow the part through the entire bending sequence. After the bending is complete, the robot places the finished products onto the pallets in the foreground.

Using vacuum cups to hold the part in place, the robot releases the part and regrips for a different bend.

Typical SimulEasy software screen program. The screen illustrates the bend lines, shows the bend sequences, and simulates the actual bending process.

Manually operated press brakes are often underutilized, yielding inconsistent output that rarely achieves the production levels that cycle times might predict. Production challenges are compounded by the overwhelming demand for good press brake operators: part quality and bend accuracy is becoming problematic as an aging and experienced work force retires. However, with new automated press brake systems, users will have a hands-off process that maintains quality and consistent output, while reducing the time between bends, organizing the set-ups and, perhaps most importantly, improves a company's position against offshore competitors.

Hydraulic down-acting press brakes are the most widely used type for bending parts such as file cabinets, computer cases, stove hoods, fabricated structure components, trucks & truck beds, metal doors and frames, large tractor/trailer trucks and HVAC components such as duct work. Integral operator involvement is required with hydraulic press brakes, especially in a manual production process. Operators must write the rake program online or offline. They must also bring the material to be bent into position, load the correct tooling and the appropriate program, run a test part, adjust tonnages to achieve the desired angles, and continue to run more parts while checking measurements periodically. However widely used this type of process might be in a sheet metal fabrication shop, it isn't without limitations — especially as the level of work force experience diminishes.

Limitations of Manual Press Brakes
Manual press brakes remain one of the most labor intensive machine tools. For many reasons they are perhaps the most vulnerable to quality variations in finished parts. Bend accuracy is critical, yet it is difficult to control when a human operator is expected to consistently apply the same amount of force to a bend throughout a shift. Oftentimes the angle of larger bends lags off near the end of a shift.

Bend accuracy can also be affected by part placement. The operator must precisely locate the part in the die, and then keep it in place until the part is clamped. In this situation, not only must the operator place the bend in the correct position on the sheet, but he must also be sure that the angle and measurement are correct. Inaccuracies caused by material variation can also affect finished parts, especially when operators don't take the time to gauge and make adjustments.

Underutilization is another limitation of manual press brakes. It is difficult to keep a press brake running all day long. Fab shops run press brakes only when operators are present, so during scheduled breaks, or lunch, or during lights-off production the press brake remains idle. And the amount of time the press brake actually spends bending metal influences productivity and utilization.

Manual press brakes rely on operator expertise for part quality. Operators change programs frequently during the day, and they also make other changes as needed. A good operator with experience does this well, but another won't necessarily produce the same quality part. It is often very difficult to find another operator who is as proficient as the one that just retired.

Another drawback of manual press brakes is worker safety. Operators are lifting pieces of sheet metal over their head day after day. Shoulder and back strain injuries are very common because of this heavy lifting, and repetitive motion injuries also occur. Companies with manual press brakes are faced often with operators needing time off to heal and the insurance costs associated with these injuries.

Part quality, production management, work force management, and worker safety are all daunting issues facing companies with sheet metal fabricating shops. But automated press brakes offer an alternative that enables companies to increase productivity while redeploying their work force to more responsible positions.

Advantages of Automated Press Brakes
Automated press brakes produce more accurate parts. Robots can repeatedly place the part on the die in the exact location, and this consistency is maintained during the entire bending process as the robot follows the part. The robot moves the gripper up as the part moves up, smoothly applying force throughout the bending sequence. The use of robots to check angles periodically and respond to material variation (known as in-process gauging) can also improve part quality.

Automated systems increase utilization of the press brake. Robots require no breaks and continue to work in lights-off production. They move faster than people, so time between bends is reduced. And the software in an automated system optimizes the bending process. The program looks at the bend order to make sure it is the best for the robot, thereby minimizing the number of times a robot has to re-grip the part.

Using automated press brakes is a hands-off process, and operators in automated production have very different responsibilities. Since they are redeployed to more of a supervisory role, injuries are reduced and companies benefit by the reduction of work-men's compensation costs.

Companies using automated systems have more flexibility to compete for a wider variety of jobs, as they can maximize their production time. These companies can expand their production capabilities without expanding their payroll or plant size.

Developing Software for Automated Press Brakes
One of the hurdles that took developers the longest time to overcome was the lack of software. Without software, developers had to build something like a specially designed gripper, see how it would work, then make adjustments from there. And if it didn't work, they'd have to start over. Not having programmable software with system design capabilities was a major impediment in the development of automated bending systems.

The press brake and the robot each had to be programmed separately, but in doing so developers could not ensure that the timing of each would work in concert with the other. Release and grip issues couldn't be completely resolved; there was just no easy way to program the robot to follow the parts through the entire bend in sequence with the press brake. But the software issue didn't just affect programming; it was also a major stumbling block when it came to setup times.

Set-up time for a press brake includes the total time it takes to get all the equipment into place to run a part. The profitability and efficiency of a press brake is measured by the number of correct and completed parts that can be produced in a given period. During set-up no parts are being made. When less time is devoted to making parts because of a lengthy set-up, the cost per part increases. Without a software program that could run offline, it was taking up to 3 weeks to program and set-up a process for the robot and the press brake to run a part.

With no standard solution available, automated system developers had to redesign all elements with each new press brake and robot system. Solutions developed by press brake manufacturers were often part-size limiting and did not include any capability to retrofit existing applications. Robotic system integrators had no software program that would lay out the entire bend sequence and write an entire robot path for customers wishing to automate their existing systems.

An Italian-based software solutions company with experience in offline programming and vision software development saw this need in the press brake market. They initially developed a program that coordinated robot paths with press brake bend sequences. But they continued to revise their software so it could incorporate numerous complicated processes. The final version of the software they developed, SimulEasy, is at the heart of the RIBS system — the Robotically Integrated Bending Solution. Automated Concepts Inc., Council Bluffs, IA, is the exclusive systems integrator in North America of the SimulEasy software, and has developed the RIBS system to offer users a completely automated package.

The RIBS System
The RIBS system is the first automated solution that can be used both by users who want to retrofit their existing equipment and by press brake manufacturers in new installations.

Unlike some robotic options, the system programs parts offline. Nothing has to be taken out of production in order to design a process for a new part, or modify a process for a current part. The system features a userfriendly programming interface that takes about one hour per part, and includes all input and output interfacing between the robot and the press brake.

There are two main components to the RIBS system: SimulEasy software and a FANUC robot. The software allows the user to program an entire bend sequence offline, then upload the program into both the press brake and robot. This program helps in the design and layout of all system components and conducts collision checking. It also assists a process engineer in tooling selection, robot grip-per design, re-grip coordination, cell layout, clearance checking, and bend sequence ordering, enabling customers to minimize cycle times with optimized processes.

Another advantage of the software is that it works with standard DXF CAD files. By utilizing a universal DXF exchange, engineers or operators with even limited CAD experience are capable of designing processes. In addition, the software program also offers process verification through a virtual 3D interface. During the offline programming phase, users can watch the entire process on the computer before ever exporting the program or stopping production. Nonetheless, press brakes are a challenge to work with and the program does not take the place of process engineers. Their skill and talent are necessary. But SimulEasy is a tool that allows a fabricator to organize and utilize a robot with pre-existing bending knowledge.

Capacity to meet specific customer needs is the driving force behind robot selection, and RIBS works with any FANUC robot. The robot can handle heavy components that might otherwise require a lift assistance device or the strength of two people. RIBS system robots will follow pieces through a bend to maintain consistent bend angles and eliminate back bending. The robot switches back and forth from making one product to another with surprising ease while maintaining quality levels, non-stop production, and a level of safety unobtainable with manual systems.

Once a part is loaded and programmed, the first time a RIBS system is employed it might take a few minutes longer than manual bending to set-up because of component changes like switching grippers and moving suction-cup locations on the regrip stand. But this extra minute or two of set-up time will be quickly absorbed by increased production. If parts have enough in common, neither gripper changes nor tooling changes will be necessary and shops can reduce the recommended lot size of 100 to 20 or fewer parts.

Automation and Competitiveness
Much fabrication business that could go offshore has already done so. Parts that remain in production in the United States are here for a reason — such as they have poor nesting profiles requiring custom dimensions and short lead times.

Today, many shop owners are more challenged by an excess of fabrication capacity in regional markets than they are by threats of outsourcing to the Far East. Everyone is trying to weather the storm amidst this excess, with the consequence being significantly tighter margins. Purchasers of fabricated products are well aware of this excess capacity and aggressive bidding wars are not uncommon. Therefore, fabrication shops must stay competitive, and automated systems can help a company do that. Increased output, re-deployed labor, and better equipment utilization all go straight to the bottom line, resulting in leaner cost-structures and easily controlled output.

In Review
Press brakes are perhaps the least automated of all machine tools, and at a time when robotic welders require higher levels of part quality the lack of automation can be problematic. Technological advances in press brakes promote quality improvements, but the return-on-investment for these pieces of equipment demands that they be fully utilized. Not at the unfactored standard of under 60 percent utilization, but truly, fully utilized so that a one minute cycle time translates into nearly 480 parts per shift. Considering the margin pressures most fabrication shops are experiencing, labor redeployment, productivity increases and lights-out production are all tantalizing possibilities.

RIBS, from Automated Concepts, is the first retrofit system available in North America that brings to fruition all these opportunities without excessively long programming times. With the help of the SimulEasy bending software, a robotic program for a new part can be created offline in just about an hour. The result? There's an automated press brake system available for nearly any part a company needs to produce.

How SimulEasy Got Started Kone s.p.a., Milan, Italy, manufactures, installs, maintains , and modernizes elevators and escalators, and services automatic doors in buildings throughout the world. Utilizing manual press brakes in their manufacturing processes, Kone was finding it difficult to maintain the standard of quality required for their products. These are typically large and heavy to the point of requiring two people to handle them and maintain their desired rate of production. The results were a workload that was demanding both in time and labor. Gausipi Casagrande, managing director of Kone, determined that "we must start to work with a robot" for these large and heavy products. He was familiar with the SimulEasy program because Kone already had a robot with an earlier version of the software. Therefore, Casagrande knew that to solve his problem he would need to incorporate the software into his process, and place a robot in front of the press brake. By automating their press brakes with SimulEasy and a Fanuc robot, Kone was able to program the robot without stopping production. The press brake operator was able to program the print of the part and then send the program to both the robot and press brake simultaneously which eliminated the step of programming both separately. In addition, Kone operators found that the simulation was real and accurate, and when implemented they reduced set-up time by 50 percent. Kone was also able to reduce its delivery time because of their shorter set-ups.

 

Edited from information provided by Automated Concepts Inc., Council Bluffs, IA. For more information call (712) 328-3410; fax (712) 328-3630; or visit www.automatedconcepts.com