Virtual Collaborations

Impedance matching for a range of different power ultrasonic transducers

Featuring Xuan Li and Jack Stevenson
Centre for Medical & Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow

February 1 at 10 am EDT

Register NOW for Virtual Collaborations 1 February 2024

Matching the output impedance of a driving system to the impedance of an ultrasonic transducer is required to maximise the transfer of energy and hence ultrasound transmitting efficiency in power ultrasonic applications. This is particularly challenging when the transducer is driven at high excitation levels and under varying load conditions. This presentation will demonstrate the theory and practical implementation of impedance matching, with static LC and transformer configurations.

LC matching is incorporated in a Langevin style ultrasonic surgical tool whose impedance presents almost resistive characteristics at series resonance, with matching parameters designed from the Butterworth Van Dyke (BVD) equivalent circuit model. The tool is then applied to ex-vivo animal tissue cutting to study the performance compared with an unmatched device.

We will show how the LC matched device can penetrate deeper into tissue than the unmatched tool, for the same ultrasonic displacement amplitude and feed rate. However, blade seizure can occur due to the change in the loading condition, which static LC impedance matching is unable to cope with.

LC matching is also applied to a miniature ultrasonic surgical tool with a much higher impedance magnitude and strong capacitive characteristics at series resonance. The matching parameters are, in this case, not readily calculated, as there is not a straightforward estimation of the BVD equivalent circuit. In this case, an optimisation of the matching parameters (L and C) for both low excitation level and high excitation level is carried out to match the high impedance of the transducer to the low output impedance of a resonance tracking system, thus aiming to achieve the largest possible displacement amplitude of the blade. Successful cutting is demonstrated in porcine bone samples.

Impedance matching can also be achieved by using a transformer between the driving system and transducer. This part of the presentation looks at a HIFU device that has low impedance at series resonance that needs to be matched to a standard RF amplifier (50 Ω). The use of a transformer will be discussed along with comparison with an LC circuit in similar conditions.

Due to the high frequency and low impedance combination of this HIFU device, a different set of challenges arises. The electrical matching theory is the same for both systems, where conjugate matching is employed to minimise the phase at series resonance. However, the series resonance of a transducer which is a small load is significantly affected by the matching network and a large drop in can be expected. This is managed through design of the transformer core material, turns ratio and total turns. Without a matching network the power reflected by the transducer back to the power amplifier is high. After optimisation of the matching transformer, reflection is significantly reduced. However, as the piezoelectric element changes impedance under load, the efficacy of the static matching network diminishes. Therefore, a discussion on the role of impedance matching under load will be presented along with findings based on the HIFU devices.

Unlimited members (Sustaining and Individual) can register at no additional charge.  Sustaining members can register up to five individuals at no additional charge.

This edition of Virtual Collaborations will be available to UIA basic members at $50 / students at $25 / nonmembers at $75. Group registration discounts ARE AVAILABLE to those companies who are basic sustaining members or non members who want to have more than one person participate.


 

Unlimited members (Sustaining and Individual) can register at no additional charge.  Sustaining members can register up to five individuals at no additional charge.

This edition of Virtual Collaborations will be available to UIA basic members at $50 / students at $25 / nonmembers at $75. Group registration discounts ARE AVAILABLE to those companies who are basic sustaining members or non members who want to have more than one person participate.

Register here for access to the January 2023 Virtual Collaborations

Registration for Virtual Collaborations also includes access to the recording after the live presentation.


Virtual Collaborations for 2024

This is a regular program of the UIA, providing an opportunity for those interested in ultrasonics to hear a presentation and then have a collegial discussion about the presentation.  Please save 90 minutes for this session.

Look forward to invites for four separate sessions during the course of the year, in February, June, September, and November.  We have selected this schedule so that we can bring you great content on a regular basis but not interfere with our annual conference or summer holidays!  And we will be adding a new wrinkle to these presentations, a mini-symposium!  The presentations in February, June and November will continue with our 1 hour format and a topic of discussion, but our September session will be an expanded 2 hour mini symposium with a series of presentations on a specific area of ultrasonic technology, ranging from ceramics, transducers, control systems waveguides and other technologies.  And don’t forget our main symposium in April!

We look forward to seeing you at these presentations during the course of the year!

Kevin Hauser & Margaret Lucas, 
Virtual Collaborations co-chairs


Interested in previous Virtual Collaborations presentations?

Contrasting Ultrasonic Design Challenges in Wire Bonding and Phacoemulsification

Featuring Mark Delsman, J & J Vision

Mark Delsman Mark Delsman is a Systems Engineer for Johnson & Johnson Surgical Vision, responsible for the ultrasonic handpieces used in cataract surgery (phacoemulsification). Mark got his start in ultrasonics at Orthodyne Electronics (and later Kulicke & Soffa), where he was an R&D Engineer and later Process Group Manager responsible for transducer design and all wedge wire bonding processes. Mark left the field of ultrasonics for a number of years, finally returning to ultrasonics at J&J. This presentation looks at a few of the surprising differences Mark has discovered in the application of ultrasonics in wire bonding and phacoemulsification.

Register here to view this session

Use of testing and finite element analysis for the design with frequency separation considerations

Featuring 

Kevin HouserDirector, IP Strategy, Engineering Fellow, Intellectual Property Center of Excellence

This edition of Virtual Collaborations will focus on the use of testing and finite element analysis for the design of waveguides and end effectors for use on power ultrasound systems.  It will include information of generalized testing of longitudinal, torsional and transverse frequencies and then using specific design changes to achieve appropriately designed frequency separations amongst all of these.

End Uses of Ultrasound

Featuring 

Dominick DeAngelis, Kulicke & Soffa 

Professor David Grewell, Chair of the Department of Industrial and Manufacturing Engineering, North Dakota State University

Kevin HouserDirector, IP Strategy, Engineering Fellow, Intellectual Property Center of Excellence

End Uses of Ultrasound

This edition of Virtual Collaborations will feature four knowledgeable ultrasonic professionals discussing uses of ultrasound which they work with regularly. 

  • Dominick DeAngelis will present Semiconductor Wire Bonding
  • David Grewell, State University of North Dakota, will discuss Biofuel Uses
  • Plastic Welding will be presented by Leo Klinstein, Dukane Corporation
  • Kevin Houser, Johnson & Johnson Medical Devices Companies, will present on Ultrasonic Surgical Instruments

Register here for September Virtual Collaborations

Rasmus Lou-Moeller

Industrial & Manufacturing Engineering, Meggit A/S

Leadfree Piezo Update

Although the EC has delayed the new regulations requiring leadfree piezo, there has been a focus on developing leadfree piezo techniques.  Rasmus Lou-Moeller, Director of Engineering and Business Development for Meggitt A/S will provide an update on leadfree piezo and how these developments can impact the future of piezo.

Want to view this critical update on the development of leadfree piezo techniques?  Register below - it will give you access to the video recording and the PowerPoint presentation.

Register to view the June Virtual Collaborations

Please email UIA if you wish to purchase any of these previous presentations:

  • Modeling of ultrasonic welding of plastics and 3D printing consolidation

    Lokesh Karthik Narayanan, Assistant Professor

    Industrial & Manufacturing Engineering, North Dakota State University

    As a researcher, Dr. Narayanan’s research interests center on the development of scalable 3D biofabrication processes that enable manufacturing of engineered tissues. Through his research, he is addressing the issues that hinder the translation of processes to the industry such as scalability and quality control. His latest research investigates the use of impedance sensing to monitor the biological quality characteristics of engineered tissue. His vision is to model the process function relationships and engineer semi-autonomous cyber-physical systems for tissue and biomedical device manufacturing.

    Dr. Narayanan has served as the instructor for core manufacturing and design courses at NC State and teaches CAD/CAM (IME 380) and automation (IME 482) at NDSU. He is a member of the Industrial and Systems Engineers (IISE), Society of Manufacturing Engineers (SME) and is a member of student relations committee in the national chapter of SME.

  • Fundamentals of Langevin Transducer Design – A Tribute to George Bromfield Featuring Tony Crandall and Jeff Vaitekunas
    Among George Bromfield’s many other accomplishments and contributions, he was a master of design of ultrasonic transducers.  This collaboration will focus on the design fundamentals of Langevin-type transducers, and the use of PiezoTran modeling software to quickly and accurately iterate to a design.  Many “tricks of the trade” that George taught will be discussed, with particular reference to the use of PiezoTran as well as more general knowledge that George has passed on to all of us to continue in his absence.

  • Ultrasound in Surgical Devices: Advances in Robotic Surgery & HIFU applications

Featuring Kevin Houser, PE,Director, IP Strategy, Engineering Fellow, Intellectual Property Center of Excellence, Johnson & Johnson, Ethicon Endo-Surgery

  • Regulatory measurement requirements for ultrasonic surgical devices: Relevance of acoustic characteristics to surgical performance

           Featuring Mark E. Schafer, PhD FASA FAIUMResearch Professor, 
           School of Biomedical  Engineering, Science and Health Systems, Drexel University 

  • Tools and techniques for characterizing transducers

           Featuring  Dr. Andrew Mathieson, Thales UK, and Mark Hodnett, NPL, UK

  • Multi-wavelength probes and blades: tuning / gain / balancing

          Presented by Jeff Vaitekunas, Ph.D., Assistant Professor, Penn State Behrend.

 To view the recording, please email uia@ultrasonics.org to register and get the link.


The first Virtual Collaboration was held on Thursday, 24 September 2020 

 

One of my favorite aspects of Ultrasonic Industry Association symposiums is the collaboration that occurs during breaks in the actual symposium presentations.  Ultrasonic technology is highly non-linear and often confounding, and bouncing thoughts with peers is practically impossible on a day to day basis due to the significant intellectual investment necessary to understand the issues.  With the current pandemic, it is not feasible for many to meet in person and have these collaborations.  That is why I am looking forward to the UIA’s virtual collaboration on applying pre-load to Langevin-type piezoelectric transducers.  Over the years I have experienced several instances of pre-load issues that at the time were confusing, but with hindsight are completely understandable.  These collaborative discussions provide the insight needed to overcome common issues that are otherwise difficult to comprehend.

 

Jeff Vaitekunas Ph.D.
Assistant Professor, Penn State Behrend