Category Archives: Tutorial

Motion Control – Case Study – Ball Screws used in Wearable Pumps!

Motion Control – Case Study: Wearable Pumps!

motion control ball screw application

 


motion control productsThe Next Generation of Intelligent Balloon Catheters Depend on Novel Designs of Ball Screw Driven Pumps

Woburn, MA –Motion Control Components Ball Screws – Case Study –

Situation:

In the realm of cardiovascular assist devices, recent developments have focused on fully implantable pumps. Among the first was HeartMate, quickly followed by Impella and HeartWare. Fully implantable devices are very expensive to develop and produce. Plus they are limited to patients who can tolerate the highly invasive procedure.

A key development in cardiovascular assist devices would be to combine the less-invasive approach of implantable balloons and external pumps with the high portability and reliability of fully implantable systems. This advance would allow the treatment of a much wider range of patients and conditions. A Steinmeyer customer set out to develop an innovative pump to achieve this advance in an intra-aortic system

 

Challenge:

One of the main technical challenges to this approach is designing a wearable pump that can carefully control the balloon’s pressurization. The pump must meet a demanding combination of performance requirements, including:

  • Precise control of pressure
  • Reversible pressurization
  • Light weight
  • Compact size
  • Quiet operation
  • Continuous performance for at least one year

Meeting these requirements was a significant challenge for their engineers. They built and tested early prototypes using traditional designs such as diaphragm pumps. But this approach required separate chambers for positive and negative pressure. The resulting systems were far too large and heavy. So they were forced to find a new approach.

motion control ball screw medical application

Results:

Their main innovation was selecting a precision ground ball screw as the drive mechanism and pairing it with a custom engineered metal bellows as the pressure chamber. Ball screws deliver exceptional thrust density while enabling high linear acceleration in both the forward and reverse directions. Surrounded by the bellows, this results in an extremely compact and quiet design. Ball screws are also known for their high efficiency (>90%), smooth operation, and long life. Their efficiency enables the use of small motors and low power consumption, which in turn reduce the size and weight of the entire system.

The engineers turned to Steinmeyer to ensure the smoothest running, highest quality ball screw. And they also knew that Steinmeyer was extremely well-qualified to provide technical support through all stages of development. Their system is meeting all of its design requirements and will soon enter late stage clinical trials.

motion control application medical

To Download a PDF of this Case Study Go To – https://ballscrew-tech.com/2017/05/26/wearable-pumps-for-medical-devices-count-on-ball-screws/

 

motion control case study wearable pumps

Future:

There is an emerging trend in the development of balloon catheters to serve cardiovascular applications. Intelligent balloon catheters may one day be key to innovation. These devices will use flexible sensors and electronics along the catheter for data collection and therapeutics. They will also incorporate balloons to apply mechanical force in the heart and arteries. Ball screw driven pumps will support these future systems as well.

About Steinmeyer

Steinmeyer is the world’s longest continuously-operating manufacturer of commercial ball screws. In the realm of linear motion control, our company has become synonymous with precision, innovation, and exacting standards of quality.

Steinmeyer’s extensive product line is used widely in drive systems for industrial machines as well as precision positioning in optical instruments, medical devices, and other mechatronic applications.

Contact Steinmeyer for further information on their extensive product portfolio:

781-273-6220

infoUSA@steinmeyer.com

Visit Steinmeyer.com

Steinmeyer Ball Screw Resource Center

 

Other Interesting Case Studies from Steinmeyer:

For the Case Study “Custom Linear Modules for Lithography Masking” CLICK HERE

For the Case Study “Pipetting” CLICK HERE


See this and other Motion Control Ball Screws, Stages, Technology Notes, Custom Components from Steinmeyer featured on:

http://MotionShop.com

http://AllMotionBlogger.com

http://Automation-Blogger.com

http://MotionControlBlogger.com

http://motioncontrolBuyersGuide.com

http://MotionControlWeb.com

http://MotionShop.net

Visit our Website
Steinmeyer Motion Control Videos
Other Steinmeyer Motion Control Ball Screw Blog

Motion Control – Steinmeyer Tutorial Series – Ball Screws – Explaining Load Capacity!

Motion Control – Ball Screw Tutorial

Motion Control Ball Screw Tutorial

 

Steinmeyer Logo

 

Tutorial presented by Steinmeyer – Many engineers are confused about this topic, especially if they don’t work frequently with ball screws. So let’s take a moment to explain the terminology.

 

BURLINGTON, MA — There are generally two load capacities given for a particular ball screw: Dynamic and Static.

Dynamic Load Capacity

The dynamic load capacity (DLC) is simply a load rating. It’s the load for a (theoretical) life of 1 million revolutions (ISO/JIS standard) or for 1 million inches of travel (ANSI standard). The DLC is critical for making lifetime calculations, since the expected life goes as the cube of the ratio of DLC to actual load. So, if the load is only 10% of DLC, then the expected life is 1 billion revolutions.

But that still doesn’t mean you could run the screw with this kind of load and expect a to achieve that life! Why? The normal maximum operating load of a general use ball screw is about 30% of the DLC. (Above that, the elastic deformation of the balls and races is too large, which may cause excessive wear.) So, if you run a ball screw with a load equal to its DLC, you may not get as much life as you expect.

Static Load Capacity

The static load capacity (SLC) indicates the load above which the screw may be damaged. Staying below SLC ensures that balls and races don’t suffer brinelling (or plastic deformation). This is critical! But bear in mind that a ball screw may be damaged in other ways with loading below the SLC: you could easily tear off the flange of the nut, snap the bearing or drive journal of the screw, or even collapse it from exceeding the buckling load.

About Steinmeyer

Steinmeyer is the world’s longest continuously-operating manufacturer of commercial ball screws. In the realm of linear motion control, our company has become synonymous with precision, innovation, and exacting standards of quality.

Steinmeyer’s extensive product line is used widely in drive systems for industrial machines as well as precision positioning in optical instruments, medical devices, and mechatronic applications.

Contact Steinmeyer for further information on their extensive product portfolio:

781-273-6220

infoUSA@steinmeyer.com

Visit Steinmeyer.com

Steinmeyer Ball Screw Resource Center


See this and other Motion Control Ball Screws, Stages, Technology Notes, Custom Components from Steinmeyer featured on:

http://MotionShop.com

http://AllMotionBlogger.com

http://Automation-Blogger.com

http://MotionControlBlogger.com

http://motioncontrolBuyersGuide.com

http://MotionControlWeb.com

http://MotionShop.net

Steinmeyer Logo
Visit our Website
Steinmeyer Motion Control Videos
Other Steinmeyer Motion Control Ball Screw Blog

Motion Control – Automation Fair in Vancouver, BC on November 6, 2019

Motion Control – Automation Fair
motion control automation fair

 

 

Motion Control - Electromate-Logo

 

We are excited to invite you to the Electromate Automation Fair on November 6, 2019. The event will take place at the Delta Hotels Burnaby Conference Centre in Burnaby, British Columbia. The Automation Fair is a great opportunity to explore new technologies and see what’s changing in the world of Automation and Motion Control. Don’t miss this opportunity to meet some of leading manufacturers in the Automation Industry, as well as like-minded industry professionals.

 

 

Motion Control Manufacturers in Attendance Include:

Advanced Motion Controls

Applied Motion Products

Exor Electronic

Galil Motion Control

Gam Gear

Kollmorgen

Macron Dynamics

Maxon Motor

Posital Fraba

Harmonic Drive

Tolomatic

Who would benefit from this Motion Control Seminar:

OEM’s, Custom Machine Builders and End Users in the following industries: Medical, Pharmaceutical, Life Science, Subsea, Robotics, Industrial Automation, Food & Beverage, Forestry, Packaging, Film & Entertainment, Scientific, and Communication Industries.

Topics Covered Include:

Industrial Automation

Motion Control

Robotics

Machine Control

Motor Control

The Agenda Includes:

Lunch will be served as well as snacks/drinks throughout the day. A host bar (beer & wine only) will be open from 1:00pm to 7:00pm.

Cost to attend the Automation Fair is FREE, however preregistration is required. Click HERE to register.

About Electromate:

Electromate’s Core Purpose is to help Manufacturers build better machines using differentiated automation technology. They specialize in Robotic and Mechatronic Solutions for the Industrial Automation marketplace. Respected by customers as a premiere source for High Performance Automation and Motion Control Components & Systems, Electromate® specializes in AC & DC Servo and Stepper Motors & Drives, Motion & Automation Controllers, Positioning Systems & Actuators, Feedback Devices, Gearing Products and HMI’s & Operator Displays, all supported via extensive product selection, just-in-timedelivery, dedicated customer service and technical engineering support.

More on Electromate can be found at

Website: http://www.electromate.com

LinkedIn: https://www.linkedin.com/company-beta/209277/

Twitter: https://twitter.com/Electromate

Facebook: https://www.facebook.com/electromateindustrial/

Blog: https://electromate.wordpress.com/

Electromate Best Blace to Work

For more information on the “Best Place to Work”CLICK HERE!

To view Electromate’s new corporate video CLICK HERE

For further information on this new product or others in our extensive product portfolio, call 1-877-SERVO99 (737-8699) or e-mail Warren Osak at sales@electromate.com or visit Electromate at: www.electromate.com


For other Motion Control Components, Applications, and Technology from Electromate go to: http://MotionControlBuyersguide.com
 

Motion Control - Electromate-Logo
Visit our Website
Motion Control - Electromate Twitter Link
Motion Control - Electromate Facebook Link

 

See this and other Motion Control Components from Electromate are also featured on:
http://MotionShop.com
http://AllMotionBlogger.com
http://Automation-Blogger.com
http://MotionControlBlogger.com
http://motioncontrolBuyersGuide.com
http://MotionControlWeb.com
http://MotionShop.net

Motion Control Tutorial – Slotted vs. Slotless Motor Technology

motion control Servo2Go-Logo

When first introduced, brushless DC motors, despite their many advantages, were cast as a costly alternative to brush-commutated motors and were typically only specified for low-power applications where long life was the primary desired requirement. Without the mechanical brush-commutator mechanism that would wear and eventually result in motor failure, brushless motors could be relied upon to deliver performance over time. As for other advantages, conventional wisdom held that brushless motors provide high speed and fast acceleration, generate less audible noise and electromagnetic interference, and require low maintenance. Brush-commutated motors, on the other hand, would afford smooth operation and greater economy. In the past decade, though, brushless motors have gained broader appeal and greater acceptance in industry for a wider range of applications previously dominated by brush-commutated products, due in part to dramatic reductions in the cost and size of electronic components and advances in motor design and manufacturing.

At the same time, manufacturers have further sought to challenge conventional wisdom by improving brushless motor design in an effort to combine the traditional advantages of brush-commutated and brushless types. A noteworthy example of how far these innovations have progressed involves the slotless (instead of slotted) construction of the brushless motor’s stationary member, or stator.

The slotless stator design originated with the goal to deliver smooth running performance and eliminate cogging, which is an unwanted characteristic especially in slower-running applications (less than 500 rpm). The absence of cogging is, in fact, the most-often cited reason for selecting a slotless brushless motor.

Slotted Motor Construction

Most brushless motors (slotted or slotless) use electronic commutation, usually Hall-effect sensors and magnets, in place of brushes. The motor’s rotor consists of a steel shaft with permanent magnets or a magnetic ring fixed around the circumference of the shaft. The magnets are responsible for producing torque. As the flux density of the magnet material increases, the amount of torque available from the rotor assembly increases.

In traditional slotted brushless motors, the stator features a group of slotted steel laminations (0.004 in. to 0.025 in. thick), which are fused to form a solid uniform stack and create a series of teeth. Wound copper coils, which produce electromagnetic fields, are then inserted into each of the slots. Together, the laminated stack and wound copper coil form the stator assembly. The return path completing the magnetic circuit consists of the laminated material outboard of the copper windings in the stator and the motor housing.

These brushless slotted motors are especially powerful, because the teeth around which the copper wire is wound place the iron closer to the magnets, so the magnetic circuit is completed more efficiently. As the air gap between iron and magnets is reduced, the torque available for the motor is increased.

However, slotted stators are known to cause cogging, which is attributed to the teeth in their construction. Cogging occurs when the permanent magnets on the rotor seek a preferred alignment with the slots of the stator. Winding copper wires through the slots tends to increase this effect. As magnets pass by the teeth, they have a greater attraction to the iron at the ends of the teeth than to the air gaps between them. This uneven magnetic pull causes the cogging, which ultimately contributes to torque ripple, efficiency loss, motor vibration, and noise, as well as preventing smooth motor operation at slow speeds. A slotless stator offered a solution to the problems experienced with cogging in slotted brushless DC motors.

Advantage of the BLDC Slotted Motor Technology

The main advantages of the slotted technology are:

  • ease of winding customization
  • increased heat dissipation
  • ability to withstand high peak torque
  • high power density

Slotted Motor Applications

The Slotted Motor is ideal for applications such as:

  • Medical Hand Tools
  • Hand held shaver system for arthroscopic surgeries
  • High speed surgical drills for ENT surgeries

Slotless Motor Construction

Instead of winding copper wires through slots in a laminated steel stack as in conventional slotted brushless motors, slotless motor wires are wound into a cylindrical shape and are encapsulated in a hightemperature epoxy resin to maintain their orientation with respect to the stator laminations and housing assembly. This configuration, which replaces the stator teeth, eliminates cogging altogether and results in desired quiet operation and smooth performance.

The slotless design also reduces damping losses related to eddy currents. These currents are weaker in a slotless motor, because the distance between the laminated iron and magnets is greater than in a slotted motor.

Slotless motors are typically designed with sinusoidal torque output that produces negligible distortion, rather then a trapezoidal voltage output. The sinusoidal output reduces torque ripple, especially when used with a sinusoidal driver. Because the slotless design has no stator teeth to interact with the permanent magnets, the motor does not generate detent torque. In addition, low magnetic saturation allows the motor to operate at several times its rated power for short intervals without perceptible torque roll-off at higher power levels.

Compared with slotted motors, slotless construction also can significantly reduce inductance to improve current bandwidth. The teeth in a slotted motor naturally cause more inductance: the coils of copper wire around the teeth interact with the iron in a slotted motor, and this interaction tends to send the current back on itself, resulting in more damping (or dragging) and impacting negatively on slotted motor response and acceleration.

In terms of delivering power, conventional slotted motors used to enjoy the advantage over slotless types, due (as noted) to the proximity of iron and magnets and the reduced air gap.

However, this advantage has virtually evaporated, in large part due to the utilization of high-energy, rare-earch magnets (such as samarium cobalt and neodymium iron boron). By incorporating these magnets, manufacturers of slotless brushless motors have been able to routinely compensate for the greater air-gap distance. These more powerful magnets effectively enable the same (or better) torque performance for slotless products compared with slotted. Eliminating the teeth and using stronger magnets both serve to maximize the strength of the electromagnetic field for optimum power output. Rare-earth magnets, along with the fact that fewer coils, or “turns,” of the wire are required in slotless motors, also help contribute to low electrical resistance, low winding inductance, low static friction, and high thermal efficiency in slotless motor types.

One more important difference between slotless and slotted designs is the rotor diameter. Slotless motors have a larger rotor diameter than slotted construction for the same outside motor diameter and will generate a higher inertia, as well as accommodating more magnet material for greater torque. For applications with high-inertia loads, the slotless product is more likely to be specified.

Slotless Motor Applications

In general, brushless motors are usually selected over brushcommutated motors for their extended motor life. (While motor life is application-specific, 10,000 hours are usually specified.) Other reasons for specifying brushless motors include a wide speed range, higher continuous torque capability, faster acceleration, and low maintenance.

In particular, slotless versions of brushless DC motors will suit those applications that require precise positioning and smooth operation. Typical niches for these motors include computer peripherals, mass storage systems, test and measurement equipment, and medical and clean-room equipment.

As examples, designers of medical equipment can utilize slotless motors for precise control in machines that meter and pump fluids into delicate areas, such as eyes. In medical imaging equipment, slotless brushless DC motors decrease banding by providing the smoother operation at low speeds. Airplane controls supply smoother feedback to pilots. And, by eliminating cogging and resulting vibration, these motors can reduce ergonomic problems associated with hand-held production tools. Other appropriate applications include scanners, robots for library data storage, laser beam reflector rotation and radar antenna rotation equipment, among many others./span)

Customization Options

Slotless brushless DC motors, as with most motors today, feature a modular design so they can be customized to meet specific performance requirements. As examples, planetary or spur gearheads can be integrated on motors for an application’s specific torque and cost requirements. Planetary gearheads offer a higher-torque alternative. Slotless motors can further be customized with optical encoders, which provide accurate position, velocity, and direction feedback that greatly enhances motor control and allows the motors to be utilized in a wider range of applications. As a low-cost alternative to optical encoders, rotor position indicators (ie. Hall Sensors) can be specified.

When using optical encoders, differential line drivers can be utilized to eliminate the effects of electrically noisy environments. Differential line drivers are designed to ensure uncorrupted position feedback from the encoder to the control circuit.

Motor Selection Guided by Application

Despite the overall design and performance comparisons reviewed here for slotless and slotted brushless DC motor types, one should remain cautious in drawing any conclusion that one type is the ultimate choice over the other. There are simply too many variables that must be evaluated, ranging from rotor size and windings to housing and special components. A given application and its requirements should (and will) be the guiding factors in selecting a particular motor type and the customized components to be incorporated.

Some encouraging news in those applications that would clearly benefit from a slotless brushless motor is that costs are coming down to be more in line with those for slotted motors. This is because of new streamlined manufacturing techniques and an increasingly available supply of powerful magnets, which are both beginning to have a positive impact on end-product costs.

Regardless of any cost differential, however, for many applications, slotless brushless DC motors will be the preferred choice to resolve specific requirement issues. While advances in electronics are beginning to be applied that promise to reduce normal cogging in slotted products as a step toward making these motors more smooth running and quiet, the industry is not there yet: slotless motors remain the best alternative where cogging and life are defining performance issues

This Tutorial and other Motion Control Tutorials are available through www.Servo2Go.com

For further information on this new product or others in our extensive product portfolio, call 1- 877-378-0240 or e-mail Warren Osak at warren@servo2go.comor visit Servo2Go.com at: www.Servo2Go.com

Servo2Go-Logo
Visit our Website
Twitter Link
Facebook Link
Powered by WordPress and ThemeMag