The First Iteration of Bending Machines
When reviewing the iteration history of bending machines, we must start with the iteration of the actuator. The actuator evolved from mechanical drive to hydraulic drive (MH/F series, 3-point series), then to direct drive with ball screws (BB series), hybrid control drive with oil-electric mix, and servo-hydraulic dual-drive control (BH series). The next iteration was the positioning device for measuring bending dimensions, which started using numerical control (NC) devices over 40 years ago, leading to a revolutionary improvement in the operability of bending machines. From the perspective of the evolution of bending machines, this can be called the "first iteration," which made a significant leap in the processing accuracy of bending products.
In the "first iteration," bending machines themselves made great progress. However, from the perspective of automating sheet metal processing, the automation of punching processes quickly reached a mature stage, while bending processes still predominantly relied on the "OneManOneMachine" production method. The development of bending automation has been slower than anticipated, mainly due to the advantages of V-bending in the bending process becoming a bottleneck for the development of bending automation.
"The Second Iteration of Bending Machines"
Fifteen years ago, the industry already had a keyword describing the development trend of bending machines - "support." This evolution can be seen in various aspects, including programming support, compensation support, operator support in bending operations, and pre-preparation support. Depending on the nature of the work, the efficiency of bending machines can vary significantly, with the lowest reaching 40%. The remaining 60% of the time is spent on tasks other than bending processing (including programming, compensation adjustment, and pre-preparation). To reduce this time, support operations have also evolved significantly.
Programming Support for Bending
Offline programming based on 3D models involves simulating bending processes before actual bending, confirming the bending sequence and the rationality of tooling usage, and then outputting the bending machining program. When processing complex bending workpieces, this approach can effectively reduce the downtime spent on interference confirmation or process ideation in front of the bending machine, thereby improving the operational efficiency of the bending machine. CampathBend by Murata Machinery is a software that supports 2D & 3D offline bending programming. It can read SCPX documents or DXF documents output by CampathSolidWorksAddin and automatically batch process SCPX documents.
Compensation Support for Bending
Due to the non-uniformity of sheet metal materials, it is challenging to achieve precise bending according to theoretical values. Compensation for bending angles is necessary. Angle sensors provide support for angle compensation operations, reducing the influence of material variations on bending angles and improving the stability of bending accuracy. This device is now widely used as a standard accessory for bending machines.
Operator Support in Bending Operations
Although offline 3D simulation is possible, operators still need to confirm the type and installation position of the tooling each time they install it on the bending machine. They can only confirm the bending sequence on the small screen of the NC device. Additionally, there are bending considerations not reflected in the drawings, which only the operators performing the actual bending can deeply understand and pay attention to. These pieces of information are rarely shared with others. To address this issue, Murata Machinery has developed a new software called Videre, which combines virtual and real elements. This software can display necessary operating information on the slide at the appropriate time.
Preparation Support
Bending machines can be used for small-batch production of various materials, thicknesses, and shapes of workpieces. As long as the bending program is generated and the tooling is exchanged, production can be easily carried out. This means that frequent tooling exchanges are required when processing different workpieces. This operation requires certain skills and experience, and it places a significant physical burden on the operator. To effectively solve this problem, we recommend the use of automatic tool exchange devices. Of course, depending on the final bending products or the workflow, the frequency of tooling exchange and the types of required tooling may vary. However, this provides a more flexible support system.
Lastly, it is important to mention safety devices. In a sense, safety and productivity are sometimes inversely proportional. However, after the acceptance of laser safety devices, safety and productivity can be directly proportional. The aforementioned support can be called the "second evolution" of bending machines. This evolution not only reduces the burden on bending machine operators but also improves the operational efficiency of the equipment.
Bending Automation and Intelligence
After going through the first two stages, the bending process will undoubtedly enter the "third iteration": bending intelligence derived from a shortage of skilled craftsmen and bending automation derived from a shortage of labor. These two production methods will come together and develop simultaneously.
Bending intelligence applies sensing technology. It obtains the information required for bending the workpiece through sensing actions before, during, and after the bending process, automatically compensating and providing confirmation feedback. For example, deflection compensation devices are designed for bending machines, and the same goes for angle compensation. However, the most ideal equipment is the one that doesn't require deflection compensation. The non-uniformity of materials determines the non-uniformity of bent products, and it is ideal to collect this non-uniform information before bending. Controlling the warping deformation of the sheet during the bending process, considering the internal tension of the material, is also ideal. Skilled craftsmen compensate for these factors based on their accumulated experience and physical senses, creating excellent products through their craftsmanship. This is what "skills of craftsmen = craftsmanship" means, and bending intelligence is the only thing that can replace these skills.
Bending Automation can solve the problem of labor shortage, and it complements Bending Intelligence. The demand for bending automation is increasing in the global market. However, to be honest, it cannot be considered a true "iteration" yet. Currently, the use of general-purpose 6-axis robots in bending systems is still quite popular, and Murata Machinery has provided such bending systems to domestic and international customers. However, from the perspective of bending automation, the use of general-purpose 6-axis robot bending systems is just one case among many. Bending machines are widely used in industries such as kitchen equipment, office furniture, structural steel in construction, automotive, and electronic devices. For these industries with small-batch and multi-variety production modes, the use of general-purpose 6-axis robot bending systems has limitations.
V-bending, which produces plastic deformation, can be performed using standard tooling, allowing for the simple transformation of flat sheets into three-dimensional shapes (2D → 3D). This is one of the important reasons why it is widely adopted in various industries. However, the process of bending flat sheets into various three-dimensional shapes has made robot programming, operation, and post-bending material handling more complex. While V-bending only requires tooling exchange for processing workpieces of different materials, thicknesses, and shapes, compensation is necessary during the operation. Although there have been advancements in angle compensation during bending, other forms of compensation and confirmation still heavily rely on manual operations. Therefore, in areas where bending automation depends on manual operations, it is necessary to supplement with bending intelligence. These are the reasons for the limitations of general-purpose 6-axis robot bending systems.
The Development Direction of Bending Automation
There are many methods to achieve bending automation. If a 6-axis robot bending system is used, the focus should be on robot programming, flexible material handling and stacking, and the use of bending intelligence for automatic compensation and confirmation. Currently, bending automation can inspect and confirm the conditions before and during bending. However, there is almost no automatic inspection of the finished products after bending. This is an unavoidable issue for places that require fully automated bending operations, such as nighttime operations. Therefore, the application of bending automation/semi-automation still requires some time.
