Connectivity

New Design for Hydraulic Power Units

Guest contributor:  Andreas Günder, Bosch Rexoth

Optimum power, less installation space: Thanks to new intellectual and design approaches, compact hydraulic power units increase the economic efficiency of machine tools.

Powerful force in a very confined space

In the production world, hydraulics are firmly established. Machine tool manufacturers appreciate hydraulics for their high power density, toughness and modular design. In the lower performance range up to 4 kW, however, there are also some challenges. Since the installation space is often limited, designers and technical purchasers are constantly looking for increasingly compact solutions.

Installation space is valuable

The demand for compact hydraulic drives is not only due to the structurally limited flexibility regarding extensions, modernization measures and refittings but also due to the requirements regarding acquisition costs and assembly times or structural extensions of the working space with given machine dimensions. In addition to the level of integration of the functions, energy efficiency often plays an important role as well. Last but not least, many manufacturers are following the miniaturization trend. If workpieces become increasingly smaller, the moved mass of the machine tool has to be decreased accordingly.

“Installation space eaters” hydraulic power units

To reduce the installation space, solution manufacturers can start mainly with the following components: hydraulic power unit and control cabinet. When considering this split, it becomes evident that compact power units which are also easy to integrate require completely new design approaches to eliminate all features which waste unnecessary space in the performance spectrum up to 4 kW and to ensure that the units are still compatible with many different machine designs.

Highly integrated design approaches

The features of such innovative design concepts according to the EU Eco-Design Directive 2009/125/EC for example include a tank which is optimized for efficient degassing and reduces the oil volume by up to 80 percent. A much more decisive factor for gaining space is, however, that all functions can actually be integrated in one small power unit – from an economic variable-speed drive for demand-based power output to sensor technology with filling level, temperature, pressure and filter contamination sensors to a completely wired frequency converter.

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Compact and ready for Industry 4.0

For the future viability of this approach with regard to Industry 4.0, a data interface is essential as well. Only with permanent condition monitoring can the operating conditions be optimized comfortably and relevant faults be detected early on. With this equipment, the user only has to connect the electric power, the data interface and the hydraulic supply during installation and the hydraulic power unit is ready for operation

New cooling with heatpipe

So-called heatpipes are considered to be a space-saving innovation regarding the cooling of hydraulic power units. Their high-performance passive thermal conduction allows for a further reduction of the frame size. The heatpipes absorb the thermal energy of frequency converter, motor and hydraulic oil and efficiently transfer it to a central heat sink such as e. g. cooling water…
This ensures an intelligently optimized thermal management within the hydraulic power unit and optimally utilizes the cooling power of the cooling water. There is no need for a separate hydraulic circuit for oil cooling. This reduces installation space, noise emissions, energy consumption and possibilities for leakage.

Heatpipe – Functional principle

Basically, a heatpipe consists of air-tightly sealed copper pipes with underpressure. Inside, there is a medium which transfers thermal energy. In the temperature range of hydraulic power units, the medium may be e.g. distilled water. The boiling temperature of the water is significantly reduced by the low pressure within the heatpipe, which means that a boiling or condensation process can already take place at low temperatures.

Functionality: If you dip the heatpipe for example in hot hydraulic oil, the thermal energy at the lower immersed part of the heatpipe is transferred to the water. The water exceeds the boiling point, evaporates and absorbs a large amount of thermal energy with low temperature difference (latent heat). The water steam rises to the upper part of the heat pipe which is cooled by e. g. a cooling element. Here, the water steam condensates and gives off the thermal energy to the cooling water. Thanks to the latent heatabsorption and dissipation, the thermal conductivity of heatpipes can be up to 1000 times higher than the thermal conductivity of copper pipes. Due to the high elasticity of the copper pipes, the heat pipe can be easily shaped. In this way, ideal heat paths can be formed inside the hydraulic power unit and the installation space can be considerably optimized. Similar application ranges with equal optimization potential can be found in computer technology. Here, the thermal energy in laptops caused by heat sources such as the CPU are transferred to the central cooling elements using heatpipes.

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Plug & Play: no control cabinet

The frequency converter has a high potential for gaining installation space as well. If it has already been equipped with Multi-Ethernet interface for Sercos, Profinet and other standards by the manufacturer, machine and plant manufacturers are able to reduce the control cabinet requirement for the hydraulic unit by up to 100 percent. As a precondition, however, the sensor technology and the motor in the power unit have to be wired to the frequency converter in such a way that the frequency converter can control the hydraulic pressure autonomously. This means that the control cabinet can not only be designed with smaller dimensions. Sometimes it can even be completely omitted together with the corresponding installation effort and related sources of error.

Conclusion

Fully integrated small power units based on a completely innovative design approach for the performance range up to 4 kW provide machine and plant manufacturers with the advantages of hydraulic drives with very little space requirements. As an alternative to purely electrical solutions, the required energy can be converted into a linear movement in a precise and costeffective manner directly at the working area using a simple hydraulic cylinder. If sensor technology, frequency converter and data interface are integrated as well, users not only benefit from comprehensive condition monitoring but also from a significantly reduced control cabinet footprint or even from a design without control cabinet.
More information fully integrated power units: www.boschrexroth.com/cytropac

Operating principle: https://www.youtube.com/watch?v=sSPemS94G2I

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CMA/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.

Ensure Optimum Performance In Hostile Welding Cell Environments

Guest contributor: Dave Bird, Balluff

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The image above demonstrates the severity of weld cell hostilities.

Roughly four sensing-related processes occur in a welding cell with regards to parts that are to be joined by MIG, TIG and resistance welding by specialized robotic /automated equipment: 

  1. Nesting…usually, inductive proximity sensors with special Weld Field Resistance properties and hopefully, heavy duty mechanical properties (coatings to resist weld debris accumulation, hardened faces to resist parts loading impact and well-guarded cabling) are used to validate the presence of properly seated or “nested” metal components to ensure perfectly assembled products for end customers.
  2. Poke-Yoke Sensing (Feature Validation)…tabs, holes, flanges and other essential details are generally confirmed by photoelectric, inductive proximity or electromechanical sensing devices.
  3. Pneumatic and Hydraulic cylinder clamping indication is vital for proper positioning before the welding occurs. Improper clamping before welding can lead to finished goods that are out of tolerance and ultimately leads to scrap, a costly item in an already profit-tight, volume dependent business.

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    Several MIB’s covered in weld debris

  4. Connectivity…all peripheral sensing devices mentioned above are ultimately wired back to the controls architecture of the welding apparatus, by means of junction boxes, passive MIB’s (multiport interface boxes) or bus networked systems. It is important to mention that all of these components and more (valve banks, manifolds, etc.) and must be protected to ensure optimum performance against the extremely hostile rigors of the weld process.

Magnetoresistive (MR), and Giant Magnetoresistive (GMR) sensing technologies provide some very positive attributes in welding cell environments in that they provide exceptionally accurate switching points, have form factors that adapt to all popular “C” slot, “T” slot, band mount, tie rod, trapezoid and cylindrical pneumatic cylinder body shapes regardless of manufacturer. One model family combines two separate sensing elements tied to a common connector, eliminating one wire back to the host control. One or two separate cylinders can be controlled from one set if only one sensor is required for position sensing.

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Cylinder and sensor under attack.

Unlike reed switches that are very inexpensive (up front purchase price; these generally come from cylinder manufacturers attached to their products) but are prone to premature failure.  Hall Effect switches are solid state, yet generally have their own set of weaknesses such as a tendency to drift over time and are generally not short circuit protected or reverse polarity protected, something to consider when a performance-oriented cylinder sensing device is desired.  VERY GOOD MR and GMR cylinder position sensors are guaranteed for lifetime performance, something of significance as well when unparalleled performance is expected in high production welding operations.

But!!!!! Yes, there is indeed a caveat in that aluminum bodied cylinders (they must be aluminum in order for its piston-attached magnet must permit magnetic gauss to pass through the non-ferrous cylinder body in order to be detected by the sensor to recognize position) are prone to weld hostility as well. And connection wires on ALL of these devices are prone to welding hostilities such as weld spatter (especially MIG or Resistance welding), heat, over flex, cable cuts made by sharp metal components and impact from direct parts impact. Some inexpensive, effective, off-the-shelf protective silicone cable cover tubing, self-fusing Weld Repel Wrap and silicone sheet material cut to fit particular protective needs go far in protecting all of these components and guarantees positive sensor performance, machine up-time and significantly reduces nuisance maintenance issues.

To learn more about high durability solutions 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.

Why Rexroth? Top Four Reasons to Choose Rexroth Drives & Controls

Todd Sharp, Motion Control Sales Manager, CMA/Flodyne/Hydradyne

CMA/Flodyne/Hydradyne is a leader in the design and commission of drive and control
systems for our customers for over 30 years, and one question that we often hear is “Why is Rexroth the best?”  There are many brands competing for the drive and control market, and here at CMAFH, we have working experience with most if not all of them. Our engineers program,  repair and upgrade many of the brands of control systems, and we have the ability to integrate any brand into our custom projects at our customer’s request. Having specialized in Bosch Rexroth products for many years, we understand the unique strengths of the product line.

Rexroth drives and controls can be differentiated from competing brands in four very distinct ways.

1. Product Breadth

The IndraDrive product family spans the power range from 100W to 4MW. This product family can operate as an open loop frequency drive/sensor less vector drive up to a multi-axis integrated motion and logic controller that can be either stand alone or drive resident. The IndraDrive product family also includes a cabinet free drive integrated motor. This entire IndraDrive product family is supported by the same software.Indradrive 2016 13187

  • Power range from 100W to 4MW
  • Range of technology from open loop V/F and sensor-less vector control to multi-axis integrated motion and logic control
  •  Integrated motion and logic control – controller or drive resident
  •  Cabinet free drive integrated motor

2. Connectivity

Rexroth’s drive and control platform supports all common communication buses including Ethernet I/P, EtherCAT, Profinet, SERCOS, CANopen, Powerlink, Profibus.
We can control 3rd party motors regardless of brand or type, and we can operate all common feedback types including TTL, 1vpp, Endat, Hiperface, SSI, resolver. Our drives are available with a 2nd encoder input with a 1MHZ input frequency. Our control supports all common machine programming languages like ladder, FB, ST, IL… plus all common IT and engineering languages like C#, C++, Java, Labview, Matlab.

  • Supports all common communication buses including, Ethernet I/P, EtherCAT, ProfiNet, SERCOS, CANopen, Keyvisual_inkl_Logos_w486Powerlink, Profibus
  • Controls all 3rd party motors regardless of brand or technology type
  • Operates all common feedback types (TTL, 1vpp, ENDAT, Hiperface, SSI, resolver) with drive based second encoder input with up to 1MHZ input frequency
  • Supports all common machine programming languages (ladder, FB, structured text, instruction list) plus all common IT and engineering type languages like C#, C++, Java, Labview, Matlab

3. Functionality

Whether it’s drive or controller based, Rexroth offers multi-zone tension control, vibration dampening/anti-slosh control, high speed registration control, advanced electronic camming and hydraulic control. We also support zoned safety control with safe torque off and full safe motion; controller or drive based. Yes, drive based safe motion control!

  • PMK2801_02R_WEBMulti -zone tension control
  • Vibration dampening/anti-slosh control
  • High speed registration control
  • Advanced electronic camming
  • Supports all common hydraulic functions
  • Integrated safe torque off and safe motion control

 

4. Support

Rexroth designs, engineers and manufactures all products they sell. All are standard and sold throughout the world. In the US, hundreds of local high-tech distributors are Rexroth trained and certified to provide full sales, service and application support.  Additionally, Rexroth maintains sales, service and application support facilities in every region of the US, plus scores more globally.

  •  All products are standard and sold throughout the world
  • Bosch Rexroth maintains sales, service and application support facilities in every region of the US and scores more globally
  • In the US hundreds of local high-tech distributors are Rexroth trained and certified to provide additional sales, service and application support

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Do you have questions about this post?  Please contact us:

About CMA/Flodyne/Hydradyne

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CMA/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.

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