Posted on : Thursday 30th July 2020 12:52 PM
Press brake machines appear in large numbers. Actually, each manufacturer has a press brake. Yet, most do not employ their machines efficiently. Bend technologies have made advancement towards quality. Still, press brake machines continue to serve as the most laborious ones.
To face global challenges, manufacturers are in constant search of how to reduce expenses for each piece. As for robotic automation, it is an appealing option due to delivering improved performance implemented in various areas of metalworking and industry, where robots have substituted operations handled manually. Robotic automation offers a highly productive and profitable performance, which can be gained by turning on the press brake switches at maximum speeds (Fig. 1). Sometimes robotic automation reduces costs up to half. However, press brake machines with robotic automation may not be suitable for some applications. In search of time-saving and cost reductions, most manufacturers do not go into every possibility and constructive solution.
Machines equipped with robotic automation are twice as expensive as the ones operated manually, dependent on settings of machines. While considering robotic press brakes, you may face some shock due to stickers. If so, analyze all the advantages that compensate the costs.
After overcoming the first shock, i.e the costs, go ahead utilizing the systems properly to ensure an acceptable return upon the primary investments within reasonable time limits.
The second shock has to do with the 1st set-up, which requires ten times as much expense as the primary set-up on manual brakes. It takes a lot of time to create one part. Nowadays rapidly changing terms there are hundreds of creative solutions. The significantly higher costs demanded to make the initial settings on robotic press brakes might deliver disadvantage and work against automation. On the other hand, automation prevents scraps caused by operators`errors. Yet, it is advisable to adjust waste. Debug the whole system while making the first-time set-up, passing through bends at every station one after another. Hundreds of workpieces can be disposed of while making the primary set-up.
Prior to taking advantage of the lower costs per unit, some other preliminary installation cost takes effect: that of every batch. The costs of performing a batch for each part will vary. Dependent on the applications, the costs of performing a batch on robotic press brakes nearly get doubled compared to the costs of manually handled brakes.
How is this brought about? Let us reflect on the bending procedure on press brakes. Blanks are picked up, then bent through brakes. It seems as if the bending process offers simplicity. Actually, this process is accompanied by quite a lot of nuances in workshops. The automation requires more stages as it is not smarter to detect blanks on its own, not precise to relate to blanks as well.
Robotic press brakes consist of a lot of elements that increase the cost to plan and layout. Even the smallest systems for pieces weighing under 35 pounds require a 500-sq.-ft area. This system needs fence cages to provide security, an inlet to the system, an entrance pallet rack, a station for more grips, a double work-piece detecting rack, a square desk, bend tooling, a rack for more tooling, a re-gripping rack, an out-going pallet bed, an outlet of systems.
On the other contrary, autonomous press brakes, with a typical payload above 500 pounds, require only 100 square feet. The only fixed component appears the machine. The tooling stand can be transported if necessary and the current work could be used in conjunction with another process. In general, the work of press brakes delivers smoothness and flexibility.
Off-line programming reduces the forced inaction on robotic as well as manually handled press brakes. Such components as computer hardware, software, IT supports, skilled staff as well as appropriate area form the whole consistency. Additional ongoing expenses might involve hardware updates, software updates, and maintenance costs.
The usage of bend software with robotic systems allows adding more pieces, selecting bend sequence and generating robot blueprints. New blueprints can be created and stored to be downloaded to the press brake later. Next, technicians make their primary operation, adjust the blueprint as needed and save it for later productions. The advantages are equally applicable for autonomous press brake machines. Though in this case no more experience, technical assistance and program time are needed.
The most important one of the components to consider is the bend itself.
Off-line programming is mostly accessible for stand-alone press brake machines. The robotized system requires software integrating programs for the press as well as for itself and loading, unloading cells.
Robotized press brakes are surrounded by such guarding elements as the light curtain, guarding of laser beams offering higher flexibility in conditions of invisible barriers. Yet, an unintentional break of beams can interrupt the operation. Security coding has to be manually reset to be sure intruders have disappeared from the protection area. Light curtains increase the primary costs of the device. For standalone options guard barriers are included in press brakes, lights of laser provide protection for the pinching once the machine cycles.
Handling of Materials
Blank delivering to the robot-unit has to be thought carefully. Blanks are possible to deliver the cell separately on the spot. No one is allowed to enter the cell in the auto-production. Part conveyors could be applied, but this will provide less productiveness. Most workshops carry sheets through over-head cranes and fork-lifts. The premature blank arrival will cause bottle-necks. Standalone press brakes do not have fixed enter systems. Blank entrance is possible from many directions and, blanks may be retrieved by operators at any time.
A robotic cell uses a coarse location system. Parts or part packages are possible to deliver within the tolerances of loads. Workpieces are placed towards the stop on the installation device by operators. Again less flexibility is provided at this point, as the manual set-up is carried out for parts. For standalone options, a blank can drop at any place in the areas of press brakes.
After the formation is accomplished, the parts are placed in buckets or stacked through manually handled plans and programs. Blank entrance happens separately for each blank or all together. Conveyors provide high efficiency, though they ensure less flexibility for the device. Mostly complete part removal is carried out through an over-head crane or fork-lift. Bottle-necks are not rare at this point. Those, who transport have to constantly return to the chamber for part unloading or removal or shutting the systems down.
Recently the carrying capacity has grown and the movement perimeter has enlarged as well. Undoubtedly, higher capacities require more ground. The robot work ranges might expand if it is mounted upon the swinging arms or carrying rails. This step has to be planned carefully for subsequent upgrades that may deliver more expenses.
Heavyweight parts are suitable for the auto system due to the troubles of processing materials manually, but mostly because of insufficient volumes, great capacities cannot be substantiated. On standalone brakes the parts are handled by an operator, however, a heavyweight part requires more than 1 operator and overhead cranes. Press brakes with their capacities and tools seem restricting factors.
Mostly, robotic grippers serve as the most crucial components of the whole framework. This is the main interface of robots and parts. Most manufacturers already take advantage of this automation when they load or unload their laser cutters or punches. Once the sizes of blanks change, this system just activates a diverse group of suckers. Yet, geometries of parts change on press brakes with every bend. To process just one part, configure the grip according to every step of the operation. When setting up a capture, the same skills are needed as in chess.
The grips are mostly customizable according to applications. Grips serve as the basis for the system, yet, this is not the case for the coordination of the required components. Each clamp, magnet or vacuum cup needs configuration to match the part shapes with each bend from flats to finals. Some smart auto attitudes unite grip configurations to match a part family. Dependent on the size of the lot, you can also use automatic interchangeable grippers.
Sometimes grip magazines are applied to produce grips that match every part in certain systems. When parts change shapes, the grips need to be moved. (Fig. 2)
Work Piece Detection and Reference
The robotized system uses magnetic fans, air cutters, and blades to remove separate sheets from stacks. A double blank-detector is required for the identification of numerous blanks. It also ceases the procedure if needed.
The square desk provides proper orientation for the sheets to be processed (Fig. 3) In most cases a gravity work-piece leveling desk is applied. It is leaned in a way that makes the gravity allocate blanks as required. As soon as parts assume their shapes, tooling clearance for the top and bottom flange, re-gripping allocations have to be precisely identified. The accuracy location unit refers to the workpiece allocation. Certain units like these, contain a sensor capable of stopping the processing in case of a mismatch of blanks. On standalone press brakes, if needed extra references, the location systems will be combined with a back gauge of a standard type.
Automation requires the least modification. For example, a back gauge sensor reports the automation system once the workpiece appears in bending location. Shaped angles may as well feedback to controllers. If already shaped parts surpass proper tolerances, controllers stop processing.
A more upgraded system provides higher adaptivity and in-process control on bending angles. It is possible to implement measurement during the process. The robot regularly checks bend angularities and respond to material changes. Yet, this adaptivity is more available in the case of standalone press brake machines handling a large range of workpieces.
Auto and manually handled options apply standardized, precision ground tooling. Mostly air-bend is used. However, instead of adaptation controls, an automation set-up can apply to the bottom when the bending angularity is 90 degree.
Sometimes a tool may not be suitable for each part. Then, tooling magazines are applicable, the sizes of which may differ significantly. The batch size determines tool changing: manual or automatic.
Robotized Systems Are Workable
When used for relevant cases auto press brakes make miracles. What are the suitable applications for robot-systems? There is no pint in using robotic systems in case of inadequate scales. One of the challenges concerning is whether you will be provided with consistent product orders by your clients. This is not certain. That is why the manufacturing industries have not accepted mass bending by the robot. But in the case of order consistency, robotic press brakes increase productiveness and profits.
Scraps are eliminated by robotized systems while processing. Still, scraps in bends may be of considerable significance. If set up manually, scraps completely depend on operators. With the latest types of controllers bearing graphical simulations, scraps might be reduced.
Robotic options provide excessive reliability even in severe conditions. They just need the correct installation and setting-up.
The system advantages include bandwidth as well. The system provides reliable performance. It is capable of working unattended during lunch or breaks or at night. Both manually handled and automated systems require the same bend and processing speeds. But the set-up is quicker on advanced standalone brakes. However, with the right settings, robotic presses continue to work.
Actually, manual press brakes could be inactive for a considerable part of every shift. So, workshops often reduce operator processing speeds by 80 % to consider this inevitable inconstancy. Robotic options need no break. They do not get tired or sick, suffer a difficult time. Yet, just as humans they are imperfect. Nowadays, as soon as the robotic system crashes, you will be paged.
Another obvious advantage is that robotic systems handle big-sized and challenging workpieces. Yet, in manual options piece raising desks or cranes provide easiness for operators saving them from hard labor.
A Wise Choice
It might be difficult to decide on the automated options. If you happen to change the press tools permanently, if you make prototypes or experience difficulties related to tools, materials or processing, then the automated option might be the wrong decision.
Still, in the case of relevant applications, robotized press brakes will surely ensure more productivity. Robots can make workpieces for stable orders providing consistency of revenues.
Robots do not eliminate troubles with skilled labor. Most workshops find it hard to find experienced operators who carry out the daily loading and unloading tasks that robotic cells require. Robots require skillful staff to be operated. It comes down to performance. Quality of parts, production planning, personnel management, and safe operation – these are possible to handle efficiently in a way, which does not demand automated systems. But operators need breaks from time to time. In the case of unexpected quantities and frequencies of orders, the matter is quite different. The costs of readjustments and long primary settings will perhaps out-weigh any cost-saving per part.