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In radiographic tilting beds the table upon which the patient is placed needs to be moved and controlled with smooth precision. In this type of application, servo motors and drives play a key role.
Fluoroscopes, angiograms and other radiographic applications can be achieved by obtaining a series of individual X-ray images that are then stitched together or animated to create increasingly detailed imagery that is suitable for expert medical analysis.
In addition to utilising advanced computer software to process the high-resolution radiography imaging, the table upon which the patient is placed needs to be moved and controlled with smooth precision – often over a wide range of angles and positions.
Servo motors and servo drives can be utilised to assure the safe and smooth movement of medical patients.
For upper and lower gastrointestinal barium enhanced studies, the table needs to smoothly tilt the patient from a horizontal position right up to a vertical position. This movement allows the liquid to flow through the patient’s digestive system while being captured in real time by the fluoroscopic X-ray source.
Each movement of the bed must be engineered to facilitate optimal operator use, to ensure maximum patient safety and to prevent extraneous patient movement during the examination.
Each bed is equipped with six Parker SMB low-inertia brushless servo motors ranging from 3 to 10 Nm, with four of the motors equipped with a holding brake for additional safety.
In addition, six SLVD-N servo drives ranging from 5 to 10 A receive command signals from the controller, amplify the signals and transmit current to the servo motors to produce the precise range of motion, torque and positioning required.
The first servo motor controls the up-and-down motion of the table for easy patient access, enabling the table to be lowered to a minimum of 43 cm above the ground, the lowest of its category. The second motor allows the table to move transversally up to 30 cm outwards. The third and fourth motors meanwhile, control the oblique projections of the X-ray source. The fifth servo motor controls the movement of the column holding the X-ray source, allowing it to extend up to 180 cm from the table surface. The sixth and final motor controls the tilting motion of the table, enabling a full 90° range of motion for fluoroscopy and other radiography applications.
Working closely with experts from Parker, the manufacturer was able to improve the reliability and movement repeatability versus the previous solution used.
“We have chosen Parker because of their reputation, quality and the reliability of their products. Furthermore, thanks to Parker’s innovative technologies, it has been possible to constantly improve the performance of our machines. Partnering with Parker is profitable, in terms of both the technical and commercial support provided with the ultimate beneficiaries being medical staff and of course the patients themselves.”
Ing. Alessandro Biasini, R&D project leader, CAT Medical Systems
Learn more about servo motors here.
Article contributed by Michelangelo Matullo, automation account manager, Central South Italy, Electromechanical & Drives Division Europe.
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Hazardous locations are operating environments in which explosive or ignitable vapors or dust are present, or are likely to become present. It is normal for various processing applications where gas, liquid or dust will be present in enough volume to cause an opportunity for them to ignite and cause a fire and/or explosion. An example would be an automated paint spray booth where the vapors in the air would ignite from a spark, or from a motor’s surface temperature that was too hot. In such environments, special motors are needed to ensure that any internal fault in the motor will not ignite, or be a source of an ignition.
A risk assessment must be taken to classify potentially dangerous locations as hazardous environments. Equipment and materials must also be suited for use in these dangerous areas. Learning the commonly used terms and design criteria used to qualify equipment will simplify your specification process.
This is important to know and understand so that if your processes are defined as creating a hazardous environment, you can take the steps necessary to specify the correct equipment into your facility that will not create the potential for people to be injured or killed; or for damages to occur from using this equipment.
To keep this information on explosion proof motor classifications by hazardous locations handy, download our whitepaper.
Explosion proof requirements for servo motors are dictated in the United States by UL674 and in Europe under the acronym of ATEX. The following provides definition to the terms that are commonly used within each of the directives. Thereafter, information on the design criteria used to qualify equipment for use in these hazardous areas.
Under UL674 directive, hazardous locations are those areas where fire or explosion hazards may exist due to the presence of substances that are flammable, combustible, or ignitable. These locations break into classes and divisions and further defined by groups and temperature classifications.
Class I – created by the presence of flammable gases or vapors in the air, or flammable liquids, in sufficient quantities to be explosive or ignitable. Class I locations are further categorized by Division (Refer to chart 1) and fall into Group A through D. (Refer to chart 2).
Class II – created by the presence of combustible dust, suspended in the air, in sufficient quantities to be explosive or ignitable. Class II locations are further categorized by Division (Refer to chart 1) and fall into Group E through G. (Refer to chart 3).
Class III – areas, where there are easily ignitable fibers or flyings, are present. These include cotton lint, flax, and rayon as examples. The fibers in a Class III area are not likely to be in the air but can collect around machinery or on lighting fixtures. A Class III location can be categorized as Division 1 or 2.
Relate to the Minimum Ignition Energy of the flammable substance and the location where it is installed. The lower the ignition energy required to ignite the gas, the more dangerous the environment.
Chart 3: Dust groups
Temperature classification – “T-Codes”
The surface temperature or any part of the electrical equipment that may be exposed to the hazardous atmosphere should be tested so that it does not exceed 80% of the auto-ignition temperature of the specific gas, vapor or dust in the area where the equipment is intended to be used.
The temperature classification on the electrical equipment label will be one of the following (in degrees Celsius):
ATEX consists of two European (EU) directives. They are:
Equipment Groups – Broken into group I and II and further broken down by category. The category definition is based on equipment design for protection.
Group I – Intended for use in underground mines as well as those parts of surface installations of such mines that are endangered by fire and/or combustible dust.
• Category M1 – ensures a very high level of protection.
• Category M2 – ensures a high level of protection.
Group II – Intended for use in surface equipment that is, or can be exposed to hazardous conditions (fire or explosion).
• Category 1 – ensures a very high level of protection against gas, vapor, mists, and dust that are present continuously, frequently, or for long periods.
• Category 2 – ensures a high level of protection for use in areas in which explosive atmospheres caused by gas, vapor, mists, and dust are likely to occur.
• Category 3 – ensures a normal level of protection for use in areas in which explosive atmospheres caused by gas, vapor, mists, and dust are unlikely to occur, or would happen infrequently.
Temperature Classes - relate to a flammable substance and its Auto Ignition Temperature.
There are various design criteria that the manufacturer can incorporate into their design. What is chosen will dictate the hazardous environment that the equipment can be used in. There are 4 “General Principles” of protection against explosion. They include:
• Explosion Containment - allows the explosion to occur but confines it to a defined area. A structure cannot fail from the explosion.
• Segregation - a method that attempts to separate or isolate the electrical parts from the explosive mixture. Practices include pressurization, encapsulation, oil immersion, and powder filling.
• Prevention - a method that limits the energy, both electrical and thermal, to safe levels under both normal and fault conditions. Practices include Increased Safety, Intrinsic Safety, Non-Incendive (simplified) and Special Protection.
• Increased Safety – must prevent the possibility of having excessive temperature or generations of arcs or sparks inside or outside the apparatus during normal operation. Accomplished by incorporating an elevated safety factor to all components that make up the apparatus (connections, wiring, the degree of protection of enclosure, etc.).
• Intrinsic - the most representative of the prevention concept and is based on the limitation of the energy stored in an electrical circuit (the circuit is incapable of generating arcs, sparks or combustible thermal effects). Intended for process instrumentation applications where the power required is less than 30 volts and 100 mA.
• Non-Incendive – similar to Intrinsic where the electrical apparatus is incapable of igniting a surrounding mixture during normal operation. They differ in that the non-incendive is not evaluated for safety under fault conditions, so as a result is not approved for Div. 1 environments.
• Special Protection - developed to allow certification of equipment that is not developed according to any of the existing protection methods. Can be considered safe for a specific hazardous location but must undergo appropriate tests and/or a detailed analysis of the design.
By helping operations personnel and engineers better understand the many factors that go into hazardous duty motor selection, the risk of explosions in facilities can be substantially reduced. Understanding the commonly used terms and design criteria used to qualify equipment provides facility managers with assurance that their operations are safe and in compliance with applicable regulations.
If you're uncertain that your servo motor will be safe in the environment in which it must operate, always consult the motor manufacturer for assistance. Never guess when worker safety is at stake.
Learn more about our options in explosion-proof servo motors by downloading our Explosion Proof Servo Motor catalog with complete product specifications.
Article contributed by Jeff Nazzaro, gearhead and motor product manager, Electromechanical & Drives, North America.
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Momentum behind Industry 4.0 and the Industrial Internet of Things (IIoT) is continuing with a growing number of smart device/product manufacturers developing sensors that communicate wirelessly with the outside world. Benefits include maintaining or improving quality production through machine monitoring, increasing process efficiency and enhancing equipment reliability through predictive maintenance.
There is a growing trend for hydraulics, pneumatics and electromechanical specialists, like Parker, to partner with their machine tool customers to deliver automation solutions with built-in intelligence, connectivity and control.
Driving this trend is the desire of machine tool manufacturers to differentiate their products by being more efficient, faster, safer and more precise. However, there often exists a requirement for considerable investment in different areas where internal skills are sometimes limited or even non-existent.
In the case of a hydraulic-based machine tool for example, manufacturers can benefit from the ability to schedule preventive maintenance operations to help avoid oil leaks, pipe ruptures and other common faults. This necessitates the collection and analysis of physical attributes such as pressure, flow and temperature. Then, to exploit this data to maximum advantage and use, the relative interaction of these parameters must be known; this is something that specialists such as Parker are best placed to advise and support.
Suppliers of automation and motion control technologies are busy rethinking their product development processes to add intelligent functions through sensing, connectivity via the internet and control through remote human-initiated or automatic inputs. These factors are important because they can elevate a simple automation process achieved through traditional ‘dumb’ mechanics, to a highly efficient, optimised application which can be managed remotely from the other side of the world if necessary.
Condition monitoring is transitioning to a whole new level, to the extent that maintenance personnel can determine whether something out of the ordinary has happened – in real-time if necessary. Every process has a ‘heartbeat’, so the challenge is to continually monitor that and ask the question: has that heartbeat changed over a certain period of time and is there a potential issue?
Only by collecting and then fully understanding data is it possible to optimise machine tool performance, minimise downtime and increase service life via the IIoT. A deep knowledge of hydraulic, pneumatic and electro-mechanical technology is the basis for the development of predictive and preventive maintenance algorithms.
The IIoT is not simply about interconnecting different systems of architecture, but also making the machine more effective at communicating through the deployment of intelligent functionality that simplifies data interpretation. The opportunities offered by the successful integration of actuators and motors (the muscle) and intelligent control (the brains), is changing the way products are manufactured, delivering enhanced capabilities, more efficient automation and simpler and easier to use production solutions.
The IIoT is about far more than sensors, it concerns the need to understand a customer’s application and determine how an interface can be provided within that process to give the company all the information it requires. This is best enabled by closer collaboration between machine tool manufacturers and suppliers of smart products and sub-assemblies who can integrate intelligent functionality into processes.
Article contributed by Michel Finck, market development manager, Electromechanical & Drives Division Europe
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Pressures to reduce overhead cost and maximize profitability have forced original equipment manufacturers and machine builders to significantly reduce their engineering spend. With a multitude of options and technologies along with complex sizing and selection process, machine design has become a burdensome process. Design engineers must select the optimal automation components amid countless complicated calculations and selection tools.
Specifying electromechanical componentry is more complex than selecting a catalog part number. System dynamics and other key considerations make engineers weary of selection from a simple attribute table. Performing the calculations required to properly size a motion system can often be a daunting and time-consuming task. Sales engineers and factory support are frequently consulted, and this often adds days to the process. Phone calls, emails and other touch points can significantly delay receiving a part number and CAD drawing.
In an environment focused on reducing engineering complexity and speeding time to design, how does one solve the challenge of sizing? Numerous sizing options exist for the implementation of electromechanical technology. Catalogs are often the starting point but do not provide confidence in your selection. Some electromechanical actuator suppliers use part configuration tools, but this does not solve the actuator sizing challenge. Some companies have created elaborate tools that function like sizing and selection software wizards walking you through a series of inputs. Application details are entered and eventually lead to a resultant product recommendation.
Parker's Virtual Engineer is one such tool and can help you streamline the sizing and selection process. Users navigate through a series of inputs covering a variety of application details that are critical to the actuator sizing process. Information like orientation, loading, condition and motion profile is collected from the software and used by a physics engine running in the background. The entire process takes only a few minutes and is designed to intake as much or as little information as you have. If you are an an engineer early in the design process, all application details may not be available or fully vetted. Virtual Engineer works with the information you do have to calculate a list of the ideal actuator solutions. All of your application details are stored for later reference, so as your design progresses you can add more detail, and your results will be further refined.
A results bar resides on the right-hand side of the screen in Virtual Engineer and is constantly updating the physics engine as additional details are available. This speeds up the design process by allowing for the quick entry and product recommendation while Virtual Engineer completes the complex calculations. You can be more confident about your results knowing that every product presented on the recommendations bar will perform to the specifications of your application.
While the results panel is helpful in giving a running tally of approved products, Virtual Engineer also offers the ability to compare multiple products along with a series of different attributes. Using the compare screen allows you to see any or all products in the results panel in a new window that sorts by any attribute you want. Here you can tie the sizing and selection process back to the features and attributes that are most critical to you. If price is more important than total travel life, or if the type of drive train is more important than the percent capacity of payload you can re-sort your results to reflect this.
Virtual Engineer is capable of further streamlining your sizing process. The ability to collaborate with Parker engineers or other colleagues through a shared project collaboration space is another benefit. Ultimately, if you are looking for support in sizing electromechanical products and speeding up your time from concept through to solution, this tool is a good fit for you.
If you would like to learn more or take Virtual Engineer for a test drive, click here or visit www.parker.com/virtualengineer.
Article contributed by Jeremy Miller, product manager for linear mechanics, Electromechanical and Drives Division North America, Parker Hannifin Corporation.
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The automotive vehicle industry has experienced introductions of several new technologies and upgrades. One significant example is the rising amount of electrical content per vehicle. Testing for vehicle and engine performance is essential in the wake of additions and conversions from each of the new technologies.
Concurrently, OEM manufacturers are facing a number of cost pressures that are fueling the dynamometer market, from both regulatory and the consumer base, leading to higher investments in R&D and testing.
The major drivers for dynamometers use for in-plant automotive facilities are test stands with enhanced accuracy, increasing demand for vehicle quality standards and increasing awareness toward quality in new markets. The challenge faced is how to get the price down on vehicles when all other costs are increasing.
Increasing electric and hybrid vehicle production will require more specialized testing stands:
Automotive plants are looking at purchasing new test stands to support the production of electric and hybrid vehicles.
Drive/control equipment on existing test stands may go obsolete, so parts and service will be hard to come by.
Production costs will rise with energy prices if existing equipment is not replaced with a more energy efficient solution.
Automotive or truck manufacturers or makers of components or sub-systems that go into a new vehicle already have test stands and dynamometer equipment that may be outdated and in need of drive/control retrofit. These customers who already have older test stands suffer from down time, trouble obtaining parts and excessive energy consumption.
OEMs looking to purchase test stands may want specialized features in the drive/control system and not every supplier can offer that. Or, they may be looking to purchase a new test stand or dynamometer and may want to specify certain equipment in addition. Our engineers will work with the test stand manufacturer on a special design as needed.
A dynamometer is a necessity in automotive vehicle testing equipment used by OEMs, component suppliers and automotive testing service providers for recording several parameters such as force, torque, power and speed of the vehicle.
The use of this testing equipment is essential throughout the production cycle of an automobile, making it a necessary component of all vehicle assembly lines. This testing equipment is also used in vehicle engine manufacturing factories and dynamometer laboratories or the automotive testing service facilities to evaluate vehicle and engine performance.
Test stands and dynamometers cover a wide range of applications, but are most commonly used to test manufactured items for adherence to specification while simulating real-world operating conditions. While “test stand” is a more general term defining a machine that could test nearly any item including pumps, automotive components or electrical components, a “dynamometer” is used to measure torque or power and is more closely associated with motor or motor vehicle testing.
A drive system is used in these applications to either provide motive force or absorb it, depending upon the type of test stand:
A pump test stand requiring a motor to spin the pump and a drive/control system to regulate the speed and torque delivered to said pump.
A dynamometer used to test an electric motor would require a second motor that would effectively act as a braking device to load the motor under test.The drive and control system would be required to absorb this energy while regulating the speed and torque during the test.
A third example would be a test stand designed to test rechargeable batteries. Here, no motive force is involved, but the test gear would charge and discharge the batteries in a controlled manner, allowing the batteries’ functionality to be evaluated.
Many test cell designs are energy wasters. Older technologies like water brakes, fan brakes or eddy current devices, for example, convert kinetic energy from the testing process to heat. Replacing these methods with a regenerative drive system can allow this wasted energy to be recaptured and returned to the power grid. In addition to reducing your carbon footprint, a solid-state drive system will quickly pay for itself in power bill savings. Energy saving features exist even within the drive system, like smart ventilation in the AC890PX series that senses internal temperature and adjusts fan speed to save energy when the unit is lightly loaded, or in cooler ambient temperatures.
Parker regenerative drives can harvest energy from the testing process and return it to the power grid, providing a substantial net reduction in a plant’s electric use. Older dynamometers that are widely in use simply burn off the excess power and dissipate it as heat, which is wasteful of resources. In the grand scheme of things, our engineering expertise in special equipment for electric and hybrid vehicle manufacturers contributes to these vehicles being efficiently manufactured and sold, resulting in less polluting gas and diesel-powered vehicles on the road.
Parker can provide a drive/control retrofit that will allow you to keep your existing mechanical equipment and enjoy more efficient operation. And, in many cases, better performance, and have the knowledge that the drive/control system is up to date and serviceable.
For example, if you have an existing test cell using DC motors as prime movers or absorbers, and do not wish to upgrade to AC technology, the DC590+ digital DC series is a flexible and economical solution for test rigs through 2000 HP. Replace your obsolete SCR units with the latest in digital DC to eliminate costly repairs and downtime, with the added benefit of IoT capabilities.
For OEMs of vehicle test stands who are looking to expand into new markets of electric and hybrid vehicle manufacturing, Parker can provide custom or specialized drive and control systems that meet the unique testing needs of these vehicles. For those competing in the more traditional markets, Parker draws from over 30 years of experience in drives and controls to provide systems that are compact, easy to maintain, and energy efficient.
Have a dynamometer application or just want to learn more? Download our Test Stands and Dynamometers Solutions brochure.
Article provided by Lou Lambruschi, marketing services manager for Parker's Electromechanical and Drives Division.
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When it comes to linear actuators, selecting the right drive technology can be a precise balancing act as there is no ‘one size fits all’ solution.
Due to the breadth of applications – from automated packaging lines and pick-and-place operations to complex machines such as 3D printers – making the correct choice is less about concentrating on a single aspect than finding the optimum balance of performance from a variety of different factors.
Most electromechanical linear actuators rely on one of five common drive train types: ball screws, lead screws, timing belts, rack and pinion tracks and linear motors.
Ball screws are ideal for high duty cycle applications and where high force density, precision and repeatability are required. The rolling ball bearings reduce friction and deliver high mechanical efficiency, even in continuous use. Ball screws can achieve moderate speed.
Lead screws are suitable for low duty cycle applications, or those requiring small adjustments. They typically only offer about half the efficiency of ball screws, so require twice the torque to achieve the same thrust output. However, lead screws provide cost-efficient and compact solutions for high-force applications.
Timing belts are simple, robust mechanisms for high-speed applications requiring long life and minimal maintenance, where precision greater than 100 microns is sufficient. They are efficient and easy to operate and can run at 100 percent duty cycle. Timing belts are available in longer lengths than screw drives.
Rack and pinion systems are useful for very long travels requiring high speed but are not known for their precision. They offer high force density but require regular system lubrication. In addition, removing system backlash from this type of drive train is not always possible, and they can be quite noisy in operation.
Linear motors offer high speed, acceleration and precision. Cost is the principal drawback, while force density is also less than other drive systems. The absence of a mechanical connection between the moving and static components of linear motors makes their use difficult in vertical applications.
The selection options for a linear drive can be grouped into the following categories: precision, expected life, throughput and special considerations (PETS).
For precision, always start with an understanding of needs relative to resolution. The other considerations are repeatability and velocity control. Linear motors and ball screws are typically best in terms of precision characteristics.
With lifespan, mechanical efficiency is the primary consideration, unless the requirement is for a dirty or harsh operating environment. High drive train efficiency is synonymous with long life and reduced energy consumption. Factors such as wear resistance, dirt resistance and maintenance requirements are also important. Due to their high efficiency and limited maintenance needs, timing belts are the go-to option in this category.
Throughput can be considered by first scrutinising the speed and acceleration or deceleration characteristics of each technology – depending on the length of linear travel required. If the need is for longer travel where more of the cycle time is spent at top velocity, speed is the most important. If shorter moves are required, acceleration and deceleration characteristics will take precedence. Linear motors are unparalleled when it comes to throughput.
Some other considerations to take into account when looking at each technology include material and implementation costs, while force density is a further increasingly important factor to bear in mind as machine designs continue to miniaturise, particularly when specifying end effectors or tooling mounted to an axis.
For more information about the four key performance characteristics to consider when choosing a linear drive train from our white paper click here to download.
Article contributed by Olaf Zeiss, product manager, Actuators Electromechanical & Drives Division Europe.
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