Forward from The FABRICATOR
By Kate Bachman
Fabricators continue to need to make parts faster, more productively, and at a lower cost than before. Electric press brake technology has advanced to resolve productivity, cost, safety, and environmental challenges. Images: Automec
Challenges currently facing fabricators related to bending and forming have not changed very much since electric press brakes were developed, although safety and concern for the environment have emerged more prominently in recent years.
Fabricators continue to need to make parts faster, more productively, and at a lower cost than before.
The skilled worker shortage remains a top challenge related to press brake operators. Outdated machines need a lot of nurturing from an operator who understands the art of bending metal—how to shim dies and calculate bend allowances and bend sequences accurately. Yet many of the highly skilled press brake operators are retiring, and not as many aspiring press brake operators are following in their footsteps.
The need to ensure employee safety has never been greater, because the human handling of press brake tooling in and near a machine that bends sheet metal has inherent hazards.
Also, the realization has surfaced that industrial equipment can play a role in creating workplaces that are better for the environment.
These are the assessments of electric press brake experts at OEMs Prima Power; Boschert Gizelis; and Automec, the USA importer/distributor for CoastOne. Automec Sales and Marketing Manager Bill Helinski, Boschert Gizelis Sales Director Jeff Snyder, and Prima Power Bending Product Manager Luca Spadina describe electric press brake technology updates and how they are helping metal fabricators solve bending and manufacturing problems.
How are electric press brakes evolving to help meet speed and productivity challenges? What are some current and critical developments?
Bill Helinski, Automec: A great number of the older hydraulic brakes in the field aren’t repeatable and have rams that can’t maintain parallelism. Operators often deal with hydraulic viscosity fluctuations throughout the day and material variances, which make setup and rework a constant chase.
Fully electric press brakes have evolved to help make bending processes easier and more reliable for operators. They don’t face any problems with hydraulic viscosity fluctuations throughout the day.
The ball-screw, servo-driven press brakes offer immediate acceleration and deceleration that make air bending operations very accurate and repeatable. Ball screw-driven press brakes read from rotary encoders on the servomotor, netting accuracy/repeatability of up to 0.00008 in. Setup time and rework can be reduced drastically as a result. When they have a specific angle dialed in, operators know what to expect from the machine from morning to afternoon.
The user interfaces on these types of machines often are equipped with graphical simulation, networking, and offline programming capabilities. Not only does this allow operators at the machines to determine their bend sequence virtually, engineers in the office can program jobs for the operators as well.
Electric press brakes consume significantly less electricity than most traditional hydraulic machines because they consume measurable energy only when the ram is in motion. Because there are no hydraulics, there are no messy hydraulic oil changes either. Automec
While the technology of ball screw-driven brakes has been around for a number of years, we have added some unique twists to these machines. Crowning is addressed with multiple ball screws across the ram on larger machines designed to distribute the force appropriately. It creates a consistent angle throughout the entire part. We call this our “automatic crowning” feature. Based on the material type, thickness, and width across the bed, our algorithm analyzes the tooling and determines the appropriate tonnage needed on each ball screw to ensure that the part is bent accurately throughout its entirety. Utilizing multiple ball screws with our larger machines also allows operators to bend metal anywhere across the width of the bed.
Jeff Snyder, Boschert Gizelis: Electric brakes are 30% to 50% faster than hydraulic press brakes. Our ElectroBend press brakes have a 0 mute point and switch instantly from high-approach speed to high torque for forming. This delivers faster cycle times.
Boschert Gizelis electric press brakes use a specialized AC servomotor. The motor has two windings—one that runs at high speed and low torque for nonbending ram movement and a second that runs at low speed and high torque for bending--that instantly switch from one to the other. This reduces cycle times compared to hydraulic press brakes because it eliminates the dwell that typically occurs in hydraulic presses when shifting from fast speed to forming speed and from down to up movement.
A hydraulic press brake ram typically moves downward, stops at a distance above the material called the mute point, shifts to the slower forming speed, reaches the bottom of the stroke, dwells as the valve shifts, and then returns up. Conversely, an electric brake eliminates the need to stop above the material using a 0 mute point; instantly switches to the forming speed and minimizes the distance the ram must travel in the slow, high-torque mode; then instantly changes direction and returns at the fast rate.
Our user-friendly ESA 660W controller is equipped with all the parameters the operator needs to adjust to maximize production. It is easier to program, easier to correct, and can upload offline programs.
It also can be adapted with robotics and tooling systems to streamline production without involving operators.
Electric models are universally faster than their hydraulic counterparts. Boschert Gizelis has improved the ElectroBend design to handle increased motor speeds while achieving greater control and correction of the forming process.
Productivity is improved by modernizing the screens, lights, motors, controls, and safety systems to reduce electricity consumption. Our press brake has a brighter work area, larger touchscreen controller, and is quieter for the operator’s comfort than previous generations. It also has fast cycle times, integrated automatic tooling and forming robots, the ability to integrate secondary systems, the data M iMeasure automatic bend measurement system, automatic thickness measurement, Laser Safe bend detection, automatic sheet followers, and is Industry 4.0-ready.
Advancements in the design and control of our ElectroCut electric shear using the electric servomotor concept has accelerated its speed from 40 SPM to 80 SPM. These improvements have offered insights as to how to use the technology better so we can apply these advancements to the ElectroBend in the future.
Modifying the design of steel components has resulted in lighter yet more rigid brakes.
Boschert electric press brakes deliver instant reactions to safety signals. The brake reacts as soon as the safety system detects an anomaly. Boschert Gizelis
Luca Spadina, Prima Power: The major difference between our servo-electric machines and our traditional servo-hydraulic press brakes is the combination of speed and accuracy--two factors that often don't go together. However, speed and accuracy are the essence of the technology we have been developing and supporting for many years. We have a mechanical structure that is ad hoc calculated to guarantee speed and precision with the servo-electric technology.
While the basic servo-electric press brake’s mechanical and structural composition hasn’t changed much over the 15 years that Prima Power has been manufacturing and selling them, the product is in constant evolution--both in terms of applications available to customers and of hardware upgrades used to move and control the axes--in step with new technologies available on the market.
A few years ago we integrated an automatic tool change storage with our eP Genius servo-electric press brake. This concept eliminates the manual setup of the machine, allowing the operator to commit their time and skills to the preparation of bending batches. During the tool change, a safety laser scanner detects the working area and protects the operator. There is no need for human intervention when it's time to reset the machine functionalities. The automatic tool change is especially suitable for minimum batches, where it is possible to estimate the machine setup, and short cycle times.
This feature can be combined with any size of press brake, serving one or two machines at a time, according to customer needs.
In addition, we can combine our eP press brakes with industrial anthropomorphic robots.
Finally, a new series of this servo-electric press brake will be available in 2022 with new technologies applied to the handling axes and an optimized footprint.
How are electric press brakes meeting safety requirements?
Spadina, Prima Power: We cannot underestimate the importance of safety, which is not only supported by electronic safety devices, but is actually integrated into our machines. The way our machines are manufactured guarantees a level of safety that would be unattainable with traditional hydraulic press brakes. By default, groups of springs push the bending axis upward and, as a result, the possible risk for the operator is reduced to levels close to zero.
Snyder, Boschert Gizelis: Boschert Gizelis is committed to maximizing the safety of its full product line, which is especially important as there are fewer experienced machine operators to provide safety guidance to new labor resources. Our electric press brakes deliver instant reactions to safety signals. There are no mechanical processes to fail or reduce reaction time. As fast as the safety system can detect the anomaly, the brake can react. Also, the ram is supported by springs that will lift the ram if there is a broken belt. It cannot fall by design. The ElectroBend is also less noisy for the operator.
Helinski, Automec: Electric press brakes meet safety requirements by using laser and light curtain safety systems. They also incorporate increased guarding around the machine to prevent people from getting behind or beside an operational press brake.
The advancements in laser safety systems are making setup much easier for operators. Many of the laser systems are connected to the traveling press brake ram so it allows for a tighter safety zone. CoastOne press brakes have a safety feature in the foot pedal so that if the operator steps hard on the pedal, it immediately stops the ram and sends it up to the top limit. This feature would free an operator if they were ever to be pinched by a part.
Our machines also run an algorithm to calculate the required tonnage for every bend. They calculate the target position and the force needed to bend the flange. If the tonnage requirement is met but the target position is not achieved, the machine will stop and throw an alarm. This informs the operator of a potential safety hazard, such as a tooling or material discrepancy.
ElectroBend press brakes have a 0 mute point and switch instantly from high approach speed to high torque for forming. Boschert Gizelis
How are they playing a role in bettering the environment?
Snyder, Boschert Gizelis: Our ElectroBend electric brake consumes 50% less energy than hydraulic equivalents. A hydraulic press brake circulates oil constantly as opposed to the electric press brake that only uses power when it is operating. Considering that if a conventional press brake operates 12 hours a day, five days a week, it will consume ~35,000 kWh a year. An electric press brake under the same time and operating conditions will consume only 17,500 kWh a year. At a rate of $0.14 per kWh, an electric press brake owner would save $2,450 per year in energy costs.
In addition, using modern screens and lights reduces energy costs while boosting clarity and visibility.
Because an electric press brake requires no oil or hydraulic fluids, all environmentally challenging fluid-related processes are eliminated. Fabricators don’t need to purchase, exchange, or dispose of petroleum-based fluids. This saves labor costs as well as there is no risk of leaks and zero fluid-based maintenance requirements.
Helinski, Automec: Electric press brakes consume significantly less electricity than most traditional hydraulic machines. Unlike hydraulic brakes, these machines do not run hydraulic pumps while powered on. Many electric press brakes consume measurable energy only when the ram is in motion. Because there are no hydraulics, there are no messy hydraulic oil changes either. The machines have great repeatability so less time will be spent reworking parts and setting up a job. This in turn equates to less time running the machine, consuming less electricity.
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