Author: CMA/Flodyne/Hydradyne

THE LARGEST FLOW ON THE MARKET

Guest contributor: Dr. Till Deubel, Head of Development, Cartridge Valves, Bosch Rexroth

When it comes to valves, maintaining performance with an increased flow rate can be extremely good news for manufacturers. It allows them to meet the same requirements with a smaller machine size or maximize manufacturing performance with a minimized footprint. 

Our brand-new WRC-4X directional high-response cartridge valves not only meet high dynamics and flow requirements, they can also be integrated into networked environments.

As they feature integrated electronics with a multi-Ethernet interface and OCI for Drives, WRC-4X valves can be integrated into networked environments even with an analog signal input.

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Next generation thinking

Once again, we’re pleased to be moving technology forward – increasing performance and communication for hydraulic actuators with our next generation of WRC-4X directional high-response cartridge valves. These valves are more dynamic and consistently achieve flows that could previously only be met by using the next highest available size. In fact, they provide the largest flow on the market.

Integrated electronics (OBE) allow the new valve series to be networked via open interfaces with higher-level control units and Industry 4.0 environments, even when used with an analog signal input. This means that the valves are ready be integrated right away into even the most cutting edge automation concepts and can benefit from predictive maintenance.

Flexing to future challenges

Our new cartridge valve blocks are ideal for applications with high flow and dynamics requirements, such as:

  • Presses
  • Die-casting
  • Injection molding machines

Using sophisticated co-simulations with flow analyses and strength calculations, our developers have optimized channel geometries and enabled different sized valves to achieve significantly higher flow levels. This means they can consistently achieve values that would previously have only been possible by using valves the next size up.

The valves can be operated via digital and analog control signal input. In both cases, the integrated electronics (OBE) enable the valves to be seamlessly integrated into digitally networked automation environments and Industry 4.0 applications. WRC-4X valves also feature an open interface that enables communication with a range of programs. So machine manufacturers and operators can incorporate the valves into condition monitoring systems and benefit from predictive maintenance.

Learn more:  https://www.boschrexroth.com/en/xc/products/product-groups/industrial-hydraulics/index

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

Safety Over IO-Link Helps Enable Human-Robot Collaboration

Guest Contributor: Tom Knauer, Balluff

Safety Over IO-Link makes it easier to align a robot’s restricted and safeguarded spaces, simplifies creation of more dynamic safety zones and allows creation of “layers” of sensors around a robot work area.

For the past several years, “collaboration” has been a hot topic in robotics.  The idea is that humans and robots can work closely together, in a safe and productive manner.  Changes in technology and standards have created the environment for this close cooperation. These standards call out four collaborative modes of operation: Power & Force Limiting, Hand Guiding, Safety Rated Monitored Stop, and Speed & Separation Monitoring (these are defined in ISO/TS 15066).

Power & Force Limiting

Power & Force Limiting is what many people refer to when speaking about Collaborative Robots, and it applies to robots such as Baxter from Rethink Robotics and the UR series made by Universal Robots.  While the growth in this segment has been fast, there are projections that traditional robots will continue to make up 2/3 of the market through 2025, which means that many users will want to improve their traditional robot solutions to “collaborate”.

Hand Guiding

Hand guiding is the least commonly applied mode, it is used for very specific applications such as power assist (one example is loading spare tires into a new car). It generally requires special equipment mounted on the robot to facilitate the guiding function.

Safety Rated Monitored Stop and Speed & Separation Monitoring

Safety Rated Monitored Stop and Speed & Separation Monitoring are especially interesting for traditional robots, and require safety sensors and controls to be implemented.  Customers wanting closer human-robot collaboration using traditional robots will need devices such as safety laser scanners, safety position sensors, safety PLCs and even safety networks – this is where Safety Over IO-Link can enable collaborative applications.

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Many of IO-Link’s well-known features also provide advantages for traditional robot builders and users:

1) Faster & cheaper integration/startup through reduction in cabling, standardized connectors/cables/sensors and device parameterization.

2) Better connection between sensors and controllers supports robot supplier implementation of IIoT and improved collaboration by making it easier to gather process, device and event data – this allows improved productivity/uptime, better troubleshooting, safer machines, preventative maintenance, etc.

3) Easier alignment of the robot’s restricted and safeguarded spaces, simplifying creation of more dynamic safety zones to support closer human-robot collaboration.

The third item is especially relevant in enabling collaborative operation of traditional robots.  The updated standards allow the creation of a “shared workspace” for the robot and human, and how they interact in this space depends on the collaborative mode.  At a simple level, Safety Rated Monitored Stop and Speed & Separation Monitoringrequire this “shared workspace” to be monitored, this is generally accomplished using a “restricted space” and a “safeguarded space.”  These “spaces” must be monitored using many sensors, both inside and outside the robot.

First, the robot’s “restricted space” is set up to limit the robot’s motion to a specific 3-dimensional volume.  In the past, this was set up through hard stops, limit switches or sensors, more recently the ANSI RIA R15.06 robot standard was updated to allow this to be done in software through safety-rated soft axis and space limiting.  Most robot suppliers offer a software tool such as “Safe Move” or Dual Check Safety” to allow the robot to monitor its own position and confirm it is where it is supposed to be.  This feature requires safe position feedback and many sensors built into the robot.  This space can change dynamically with the robot’s program, allowing more flexibility to safely move the robot and assure its location.

Second, a safeguarded space must be defined and monitored.  This is monitored using safety rated sensors to track the position of people and equipment around the robot and send stop (and in some cases warning) signals to the safety controller and robot.  Safety Over IO-Link helps connect and manage the safety devices, and quickly send their signals to the control system.

In the past, integrating a robot with safety meant wiring many safety sensors with long cable runs and many terminations back to a central cabinet.  This was a time consuming, labor intensive process with risk of miswiring or broken cables.  IO-Link significantly reduces the cost, speed and length of connections due to use of standard cables and connectors, and the network approach.  It is also much simpler for customers to change their layout using the network, master & hub approach.

Customers wanting collaborative capability in traditional robots will find that Safety Over IO-Link can significantly simplify and reduce the cost of the process of integrating the many advanced safety sensors into the application.

To learn more, visit www.balluff.com.

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized  Balluff distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

Robot Collaborative Operation

Guest contributor: Tom Knauer, Balluff

In previous blogs, we discussed how “Safety Over IO-Link Helps Enable Human-Robot Collaboration” and “Safety & Productivity”. We’ll build on these blogs and dive more deeply into two robot collaborative operating modes: Safety-Rated Monitored Stop (SRMS) and Speed & Separation Monitoring (SSM).

Human-Robot Collaboration

Human-robot collaboration has received a lot of attention in the media, yet there is still confusion about the meaning and benefits of various types of collaboration. In a previous blog we briefly discussed the four collaborative modes defined by the global standard ISO/TS 15066. The most well-known mode is “power & force limiting”, which includes robots made by Universal Robots and Rethink. As the name implies, these robots are designed with limited power and force (and other ergonomic factors) to avoid injury or damage, but they are also slower, less precise and less powerful than traditional robots, reducing their usefulness in many common applications.

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The safety-rated monitored stop (SRMS) and speed & separation monitoring (SSM) modes are very interesting because they allow larger, more powerful, traditional robots to be used collaboratively — though in a different manner than power & force limited robots. The updated standards allow the creation of a shared workspace for the robot and human and define how they may interact in this space. Both SRMS and SSM require this shared workspace to be monitored using advanced safety sensors and software, which create a restricted space and a safeguarded space. With SRMS, the robot stops before the operator enters the collaborative workspace — this requires a safety sensor to detect the operator. Similarly, in SSM the goal is to control the separation distance between the human and robot, but it can be dynamic, rather than static as in SRMS. The SRMS separation distance can never be less than the protective distance and this requires sensors to verify the separation.

Spaces

The robot’s restricted space is a 3-dimensional area created to limit where the robot can operate. In the past this was done through limit switches, hard stops or sensors such as Balluff’s BNS; now the standards have been updated to allow this to be done in software with internal robot feedback that can dynamically change to adapt to the robot’s programmed operation. The robot controller can now restrict the robot’s motion to a specific envelope and monitor its actual position against its programmed position within this envelope using software tools such as Safe Move or Dual Check Safety.

The safeguarded space is defined and monitored using safety sensors. The robot might know and assure its own safe position within the restricted space, but it doesn’t know whether or not a person or obstruction is in this space, therefore a safeguarded space needs to be created using safety sensors. Advanced sensors not only detect people or obstructions, but can also actively track their position around the robot and send warning or stop signals to the safety controller and robot. Safety laser scanners, 3D safety cameras and other safety sensors can create zones, which can also be dynamically switched depending on the operating state of the robot or machine.

Closely coordinating the restricted space and safeguarded space creates a flexible and highly productive system. The robot can operate in one zone, while an operator loads/unloads in a different zone. The robot sensors monitor the restricted space while the safety sensors monitor the safeguarded space – and when the robot moves to the next phase of operation, these can dynamically switch to new zones. Warning zones can also be defined to cause the robot can slow down if someone starts to approach too closely and then stop if the person comes too close.

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System Linkages

Linking the restricted space and safeguarded space to create an effective, closely coordinated human-robot SSM/SRMS collaborative system requires several elements: a high performance robot and controller with advanced software (e.g. Safe Move), a fieldbus and a variety of built-in and external sensors (standard and safety).

Significant growth in robot collaborative applications utilizing safety-rated monitored stop (SRMS) and speed & separation monitoring (SSM) will occur as robot users strive to improve productivity and safety of traditional robot systems – especially in applications requiring faster speed, higher force and more precision than that offered by power & force limited robots.

To learn more visit www.balluff.com

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized  Balluff distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

Changing the Paradigm from Safety vs. Productivity to Safety & Productivity

Guest Contributor: Tom Knauer, Balluff

In a previous blog, we discussed how “Safety Over IO-Link Helps Enable Human-Robot Collaboration”. It was a fairly narrow discussion of collaborative robot modes and how sensors and networks can make it easier to implement these modes and applications. This new blog takes a broader look at the critical role safety plays in the intersection between the machine and the user.

In the past, the machine guarding philosophy was to completely separate the human from the machine or robot.  Unfortunately, this resulted in the paradigm of “safety vs. productivity” — you either had safety or productivity, but you couldn’t have both. This paradigm is now shifting to “safety & productivity”, driven by a combination of updated standards and new technologies which allow closer human-machine interaction and new modes of collaborative operation.

Tom_Safety1.pngThe typical machine/robot guarding scheme of the past used fences or hard guards to separate the human from the machine.  Doors were controlled with safety interlock switches, which required the machine to stop on access, such as to load/unload parts or to perform maintenance or service, and this reduced productivity.  It was also not 100% effective because workers inside a machine area or work cell might not be detected if another worker restarted the stopped machine.  Other drawbacks included the cost of space, guarding, installation, and difficultly changing the work cell layout once hard guarding had been installed.

We’ve now come to an era when our technology and standards allow improved human access to the machine and robot cell.  We’re starting to think about the human working near or even with the machine/robot. The robot and machinery standards have undergone several changes in recent years and now allow new modes of operation.  These have combined with new safety technologies to create a wave of robot and automation suppliers offering new robots, controllers, safety and other accessories.

Standards
Machine and robot safety standards have undergone rapid change in recent years. Standard IEC 61508, and the related machinery standards EN/ISO 13849-1 and EN/IEC 62061, take a functional approach to safety and define new safety performance levels. This means they focus more on the functions needed to reduce each risk and the level of performance required for each function, and less on selection of safety components. These standards helped define, and made it simpler and more beneficial, to apply safety PLCs and advanced safety components. There have also been developments in standards related to safe motion (61800-5-2) which now allow more flexible modes of motion under closely controlled conditions. And the robot standards (10218, ANSI RIA 15.06, TS15066) have made major advances to allow safety-rated soft axes, space limiting and collaborative modes of operation.

Technology
On the technology side, innovations in sensors, controllers and drives have changed the way humans interact with machines and enabled much closer, more coordinated and safer operation. Advanced sensors, such as safety laser scanners and 3D safety cameras, allow creation of work cells with zones, which makes it possible for an operator to be allowed in one zone while the robot performs tasks in a different zone nearby. Controllers now integrate PLC, safety, motion control and other functions, allowing fast and precise control of the process. And drives/motion systems now operate in various modes which can limit speed, torque, direction, etc. in certain modes or if someone is detected nearby.

Sensors and Networks
The monitoring of these robots, machines and “spaces” requires many standard and safety sensors, both inside and outside the machine or robot. But having a lot of sensors does not necessarily allow the shift from “productivity vs. safety” to “productivity & safety” — this requires a closely coordinated and integrated system, including the ability to monitor and link the “restricted space” and “safeguarded space.” This is where field busses and device-level networks can enable tight integration of devices with the control system. IO-Link masters and Safety Over IO-Link hubs allow the connection of a large number of devices to higher level field busses (ProfiNet/ProfiSafe) with effortless device connection using off-the-shelf, non-shielded cables and connectors.

Balluff offers a wide range of solutions for robot and machine monitoring, including a broad safety device portfolio which includes safety light curtains, safety switches, inductive safety sensors, an emergency stop device and a safety hub. Our sensors and networks support the shift to include safety without sacrificing productivity.

To learn more about Safety over IO-Link, visit www.balluff.com

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized  Balluff distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

How do I justify an IIoT investment?

Guest contributor: Will Healy III, Balluff

Many engineers and managers I meet with when presenting at conferences on Smart Manufacturing ask some version of the question: “How can we justify the extra cost of Industrial Internet of Things (IIoT)?” or “How do I convince management that we need an Industry 4.0 project?” This is absolutely a fair and tough question that needs to be answered; without buy-in from management and proper budget allocation, you can’t move forward. While an investment in IIoT can deliver major payoffs, the best justification really depends on your boss.

I have seen three strong arguments that can be adapted to a variety of management styles and motivations.

1) Showing a ROI through Reducing Downtime

“Show me the money!” I think everyone has a manager with this expectation. It may seem like a daunting task to calculate or capture this information, but by using a team, knowing your KPIs and applying anecdotal feedback, you can get a good initial picture of the ROI that an IIoT project will bring to the organization. Many people have shared with me that their initial project’s ROI has “funded the next project.” There is a really great article from MetalForming Magazine that discusses how exactly to do this with the tables and forms they used at ODM Tool & Manufacturing.

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2) Corporate Goals for Productivity and Utilization

We can be successful getting support for a project when we link corporate goals to project goals. Smart Industry publishes a research project each year that investigates trends in the manufacturing space in regards to digital transformation initiatives. This report cites that the three top benefits manufacturers are seeing are: improving worker productivity (3rd 2016), reducing costs (1st 2016) and optimizing asset utilization (2nd 2016). These goals are driving investments and showing actual results for manufacturers both large and small. However, the report also revealed that more than half of manufacturers cite workforce skills-gap issues as their largest roadblock and this is, I believe, why we saw improving worker productivity move to the top spot. We must bring efficiency and effectiveness to the people we have.

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3) Your Competitors are Investing in IIoT!

If you have a boss that worries about falling behind, this can be a motivating argument. Control Engineering recently published a study of manufacturers and how they are investing in IIoT technologies. The largest investments are coming with sensors, connectivity and data analytics. But what is most shocking is that on average IIoT budgets are $328,160, with 18% budgeting more than a half-million dollars. If you want to keep up with the rapid pace of change in the global market, an investment in IIoT is a requirement to remain competitive.

If you are looking for support and partnership on your IIoT projects, we are experienced at utilizing IO-Link, smart sensors and RFID to enable Industry 4.0 and Smart Manufacturing projects.

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized  Balluff distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

Embedding axis controllers made by any manufacturer

Guest contributor: Theobald Herrmann, Bosch Rexroth

Automating hydraulic drives as easily and conveniently as electrical ones with combined monitoring and remote maintenance of all the technologies used – this increasingly important economic requirement can be fulfilled using valves with integrated axis controllers (IAC). What can they offer and how easy is it to implement manufacturer-independent integration at controller level?

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Bus systems play a key role in automation. They provide a flexible way of saving time and money when integrating hydraulic drives into higher-level control networks. However, in order to give the engineering plenty of freedom, this should ideally be independent of the controller manufacturer.

Ethernet – open communications standard

The basis for this manufacturer-independent communication is the network standard Ethernet. Thanks to the large address space and switch cascading facilities, networks can then be scaled to any size and can give an almost unlimited number of participants equal bus access. The most common Ethernet-based bus systems used in industrial automation to control hydraulic axes are SERCOSProfinet RTEthernet/IPEtherCAT, Powerlink and Varan.
All these bus systems can use multi-Ethernet interfaces to provide flexible availability – both for the engineering and for the end user.

What can IAC valves achieve with multi-Ethernet interfaces?

Multi-Ethernet interfaces are a key component of control valves with integrated digital axis controllers (IAC). The integrated switch (bus in and bus out)
makes it easy to comprehensively integrate your hydraulic drives into a uniform control concept. Using standardized M12 technology also enables you
to efficiently integrate a variety of sensors. The software-based control functions are particularly interesting to users. They enable the motion control
of a hydraulic drive to be handled in the same way as an electric one, ultimately depicting the operation and control of both types of drives in exactly the same way.

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Specific hydraulic axis control functions

Viewed precisely, an IAC (Integrated Axis Controller) is a digital controller equipped with control and regulation algorithms that is integrated into the valve together with all the necessary sensor interfaces for controlling position, pressure, force and flow. The extended function range includes alternating control (position, force) and status feedback for position control. This means that hydraulic motion sequences can be quickly implemented without the need for any programming. Another advantage is that control algorithms and parameters can be integrated into the valve and then selected by the higher-level controller as appropriate for the specific application. In this way, possibly supplemented by electric drives, they can be used as a cost-effective way of implementing tailored machine concepts and individual application requirements.

Commissioning, monitoring and engineering

Using standardized M12 technology reduces the cabling effort required and permits faster commissioning. Additional time and cost are saved by the wizard integrated into the software that guides the user through the few steps needed before final commissioning and also calculates all the necessary control parameters. Important for the plant’s availability are monitoring functions which, among other things, detect tracking errors and monitor the limits of travel.
In addition to these, some manufacturers also provide software tools to help motion control system users with commissioning and parameterization, and diagnostic functions such as multi-channel oscilloscopes and data loggers, so that the number of interfaces can be kept as low as possible – making the system faster and easier to configure.

Integrated machine safety (safe stop)

For the engineering IAC valves facilitate a modular construction system that can flexibly enhance system concepts. And not least, these include internally implemented DGUV-certificated safety functions. This gives you an economical and future-proof way to lay the foundations for safe stop, for instance by shutting down a channel as specified in EN 13849-1, and thus fulfill the requirements of the Machinery Directive even for large-scale plants.

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Case study 1: High precision control tasks

The role that IAC valves play in the accuracy of machine tools is made very clear by the example of a new rotary transfer machine with 54 electrical and hydraulic CNC axes. For this new development the manufacturer not only made use of a powerful CNC system solution with real-time communication via SERCOS, but also incorporated a module in controller format with software that was already capable of taking into account all the special features of fluid technology and was thus able to separate the drive level from the control level. This enables the machine to be constructed more compactly and with lower heat input. Thanks to the stable temperature, the vibration-damped sleeves of the circular array of processing axes can achieve a repeatable precision in the hydraulic servo axes of less than +/- 1 μm, corresponding to 5 μm on the workpiece. The travel speed is up to 30m/min.

Case study 2: A retrofitted core shooting machine

In addition to new designs, IAC valves with multi-Ethernet interfaces also offer considerable potential when it comes to modernizing legacy machines. For example, the well thought-out retrofit of a 50 year old core shooter coupled with new hydraulic components resulted in significantly improved efficiency. A total of eight IAC valves regulate the hydraulic cylinders on the basis of the set positions given by a CNC controller. Their possibilities and high level of precise repeatability made it possible to reduce the figures for setup time (system changeover) and waste (nibs). Altogether, despite operating three shifts, the machine’s availability increased by more than 10%, corresponding to 500 hours. Using a secure logic controller meant that safety was also brought up to date.

Conclusion

IAC valves with multi-Ethernet interfaces and integrated axis controllers enable mechanical engineering companies to easily utilize the productivity potential offered by hydraulic and hybrid drives.

Combining them with engineering tools, including industry-specific and application-specific control structures makes it possible to cost-effectively
implement tailored machine concepts and modernizations, with the result that the manufactured results can be optimized faster and more easily.

More informationwww.boschrexroth.com/iac

Moviehttps://www.youtube.com/watch?v=fVBOYCP31P0

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.

New hydraulic design for presses

Guest contributor: Stefan Zimmerman

New drive concept makes hydraulics economical and intelligent

By means of variable-speed pump drives, new, patented hydraulic axes simplify the design and control of presses of any kind. They considerably reduce the power consumption as well as the required oil quantity by up to 90 percent. To this extent, the control technology of a valve control moved into the software of intelligent servo drives of a displacer control. This reduces the complexity and opens up new levels of flexibility and of condition monitoring.

Worldwide, the climate change has increasingly drastic effects on the everyday life. Thus, governments and international organizations have defined climate targets in order to limit the CO2emissions. What has already become standard in light bulbs and household devices also takes increasingly more effect in the industry. Energy-efficiency has become a decisive criterion for the machine users when it comes to the selection of machinery and systems. They expect a considerably increased output with clearly reduced current and resource consumption. Apart from that, numerous companies have already publicly obliged themselves to reduce their CO2 emissions by defined quantities. They can only achieve these targets if new machinery and systems are considerably more energy-efficient. So it is the challenge of machine manufacturers to develop new concepts.

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Using the hydraulic force density as required

In large systems with very high processing forces as they are required for forming methods, the hydraulics as main drive is one of the largest power consumers. The end users have accepted this for a long time as they wanted to have the maximum force available at any time, even if the process did not permanently require it. Modern hydraulic drives distinguish themselves by the physical unique selling points such as power density and robustness; however, they clearly reduce the power consumption by controlling the displacer as required. Thanks to its hybrid concept, the new hydraulicAxis patented by Bosch Rexroth for presses of different kinds, from low to high drive power, connects the advantages of hydraulics with those of the electric drive technology. First equipment according the new concept has shown that the power consumption can be reduced by more than 30 percent. The required oil quantity of the hydraulic installation can be reduced by up to 90 percent.

Conventional hydraulic systems

For decades, conventional systems have proven of value for presses in the medium and high performance range as drive technology of choice. In this connection, these systems mostly work with a central hydraulic power unit with several variable displacement pumps.  Moreover they are operated by electric motors directly connected to the mains. Apart from that, central or decentralized manifolds with on/off and proportional servo valve technology are required in order to control the cylinder(s) in rapid traverse, working or pressing mode and in the so-called return.

One disadvantage of this concept are idling losses during the standstill times. In the control of the cylinders, there are also throttle losses caused by the valve control. There is partly considerable heat introduction into the hydraulic oil, which must afterwards be compensated again by corresponding cooling.

Hydraulic axis replaces central power unit

A new, patented hydraulic concept replaces the previously common central power unit with valve control by a patented hydraulic axis with speed-controlled displacer control and a closed, decentralized fluid circuit. The hydraulic axis consists of a differential cylinder with a cylinder chamber and ring chamber. The cylinder chamber is for a powerful working movement and the ring chamber for the fast rapid traverse movement. An auxiliary cylinder takes up the oscillating volume during the different movements and in this way creates a closed circuit. A central oil tank is no longer necessary and thus completely omitted.

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The flow is generated by variable-speed pump drives. In order to satisfy the high precision and dynamics requirements, servomotors in combination with adjustable axial piston pumps lend themselves. Thus, all options of the 4-quadrant operation are available to the design engineers. With several cylinders, a corresponding number of Hydraulic axes is used. The synchronization control is performed by the software of the intelligent servo drives, synchronized by means of real-time communication.

Reversal of the movement by changing the direction of rotation

The area switchover for the relevant movement is effected by means of two valves. During the pressing process, the cylinder areas are large. Thus, the cylinders reach high forces at low velocity. During the return of the cylinders, however, the areas in the ring chamber are small in order to achieve the maximum rapid traverse velocity with low forces and to thus reduce the downtimes of the presses. For the reversal of the movement, the servomotors change their direction of rotation. If adjustable axial piston pumps are used, the swash plate of which can be swiveled through zero, the direction of the movement can also be changed by adjusting the swivel angle.

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Energy efficiency in practice: Presses consume more than 30 percent less

The hydraulic axis works in a strictly need-oriented manner. At partial load, the servo drive controllers reduce the speeds of the pump motors to the lowest value possible. During standstill times, e.g. for cooling down the tools, the motors are standing and do not consume any energy. During that time, safety valves support the return. Depending on the cycle times, variable-speed pump drives allow for energy savings of more than 80 percent as compared to constantly driven power units without variable displacement pumps. In practice, the first presses with hydraulic axes achieved reduced consumption of 30 percent as compared to already energetically optimized, conventional hydraulic solutions.

BR_Homburg_Booster-105Regarding the Sytronix family, Rexroth offers more than one hundred pump drives with variable speed relating to power and function. These can be integrated into all usual automation structures thanks to multi-Ethernet interfaces.

Exceeding the savings due to the need-based closed-loop speed control, additional functions increase the energy efficiency of the presses even further. In the lowering movement, the servomotors recuperate the braking energy and either feed it into an electric accumulator, make it available to other actuators, e.g. handling axes, via an intermediate circuit or feed it back into the mains.

Synchronization control of the hydraulic cylinders via intelligent software

The synchronization control can be effected via all common real-time protocols such as PROFINET, Ethernet IP, EtherCat or Sercos if the servo drive controllers provide corresponding multi-Ethernet interfaces. Changes in motion sequences are only transmitted via the machine control by means of software command to the intelligent drives. Mechanical adjustment works at the hydraulic axis are not necessary. So due to short changeover times, end users gain flexibility. At the same time, you can continuously document the manufacturing processes of every component by means of the servo-drive data. This satisfies the increasing demands on the traceability of products.

90 percent less hydraulic oil – central tank omitted

Due to the new concept of the hydraulic axis, the movements are primarily controlled via variable-speed pumps rather than the throttling of the flow by the valves. So considerably less heat is introduced into the hydraulic oil and only minor agitation results. Result: In the first presses with hydraulic axes, the manufacturer could reduce the oil volume from e.g. 10,000 liters to only 900 liters. This saves space for the tank and reduces the operating costs as in an oil exchange, less than ten percent of the previously used oil quantity have to be purchased and disposed of.

An additional advantage is the clearly reduced average noise emission. With variable-speed pump drives, it is up to 20 db(A) below that of constantly driven pumps. During standstill, the noise level of the hydraulics falls to zero. Due to the omitted tank and complex piping for a power distribution, resonance bodies for the structure-borne sound are omitted. With the new concept, the expenses for the noise insulation are considerably lower.

Easier hydraulic construction with quick commissioning

For manufacturers of hydraulic presses, the conversion to hydraulic axes brings about considerable savings in the design, assembly and commissioning. Tank, cooling and piping are completely or largely omitted as is the valve technology. The variance of different motion sequences is moved from the valve technology into the drive controller software. Here, Bosch Rexroth has, for example, integrated best-in-class controllers for different force/path and synchronization controls. Due to the corresponding commissioning software, the engineers don’t even need in-depth hydraulic knowledge for the initial commissioning. Software wizards propose suitable parameters. This considerably shortens the commissioning phases of a hydraulic press.

Condition monitoring increases the availability

The data that is gathered by the intelligent servo drives anyway and that can be amended by more sensors is particularly interesting for end users. It forms the basis for condition monitoring strategies increasing the availability. Based on the analysis of the data, the corresponding software identifies wear and errors before they will lead to standstills. So machine downtimes are replaced by scheduled maintenance measures.

Find out more about self-contained hydraulic actuators here.

cropped-cmafh-logo-with-tagline-caps.pngCMA/Flodyne/Hydradyne is an authorized Bosch Rexroth distributor in Illinois, Wisconsin, Iowa and Northern Indiana.

In addition to distribution, we design and fabricate complete engineered systems, including hydraulic power units, electrical control panels, pneumatic panels & aluminum framing. Our advanced components and system solutions are found in a wide variety of industrial applications such as wind energy, solar energy, process control and more.