Thick film PZT transducer arrays for particle manipulation

This paper reports the fabrication and evaluation of a two-dimensional thick film PZT ultrasonic transducer array operating at about 7.5 MHz for particle manipulation. All layers on the array are screen-printed and sintered on an Al2O3 substrate without further processes or patterning. The measured dielectric constant of the PZT is 2250 ± 100, and the dielectric loss is 0.09 ± 0.005 at 10 kHz. Finite element analysis has been used to predict the behaviour of the array and impedance spectroscopy and laser vibrometry have been used to characterise its performance. The measured deflection of a single activate element is on the order of tens of nanometres with 20 Vpp input. Particle manipulation experiments have been performed by coupling the thick film array to a capillary containing polystyrene microspheres in water

Screen-printed ultrasonic 2-D matrix array transducers for microparticle manipulation

This paper reports the development of a two-dimensional thick film lead zirconate titanate (PZT) ultrasonic transducer array, operating at frequency approximately 7.5 MHz, to demonstrate the potential of this fabrication technique for microparticle manipulation. All layers of the array are screen-printed then sintered on an alumina substrate without any subsequent patterning processes. The thickness of the thick film PZT is 139 ± 2 μm, the element pitch of the array is 2.3 mm, and the dimension of each individual PZT element is 2 × 2 mm2 with top electrode 1.7 × 1.7 mm2. The measured relative dielectric constant of the PZT is 2250 ± 100 and the dielectric loss is 0.09 ± 0.005 at 10 kHz. Finite element analysis was used to predict the behaviour of the array and to optimise its configuration. Electrical impedance spectroscopy and laser vibrometry were used to characterise the array experimentally. The measured surface motion of a single element is on the order of tens of nanometres with a 10 Vpeak continuous sinusoidal excitation. Particle manipulation experiments have been demonstrated with the array by manipulating Ø10 μm polystyrene microspheres in degassed water. The simplified array fabrication process and the bulk production capability of screen-printing suggest potential for the commercialisation of multilayer planar resonant devices for ultrasonic particle manipulation

A Motion Control System Design for an Ultrasonic Planetary Core Drill (UPCD) Unit

A prototype of a motion control system for an Ultrasonic Planetary Core Drill (UPCD) tool is presented. This system is designed to maintain a consistent dynamic behavior in the ultrasonic horn/free-mass/drill bit stack during ultrasonic-percussive drilling into a range of non-homogeneous rocks. The control system is a simple negative feedback loop which employs the output of the P100 control unit (manufactured by Sonic Systems Ltd) that powers the ultrasonic transducer, ensuring that the drill tool is advanced while a steady ultrasonic vibration level is maintained. This paper describes the mechanical design of the test rig, the control system design and an evaluation of its performance

A Motion Control System Design for an Ultrasonic Planetary Core Drill (UPCD) Unit

A prototype of a motion control system for an Ultrasonic Planetary Core Drill (UPCD) tool is presented. This system is designed to maintain a consistent dynamic behavior in the ultrasonic horn/free-mass/drill bit stack during ultrasonic-percussive drilling into a range of non-homogeneous rocks. The control system is a simple negative feedback loop which employs the output of the P100 control unit (manufactured by Sonic Systems Ltd) that powers the ultrasonic transducer, ensuring that the drill tool is advanced while a steady ultrasonic vibration level is maintained. This paper describes the mechanical design of the test rig, the control system design and an evaluation of its performance

The Development of the European Ultrasonic Planetary Core Drill (UPCD)

Future exploration missions to rocky bodies within the Solar System may wish to utilize drill systems on landed vehicles which simply cannot deliver the weight on bit, or accommodate the mass and volume levels which are required for the use of existing drill technology. This issue is being tackled by the development of the Ultrasonic Planetary Core Drill (UPCD) project. This paper shall detail the development effort of this drill to date, describing how lessons learned from early technology have informed the current design. Details of the Concept of Operations, the routine by which the drill samples and caches rocks for later analysis will also be presented, with an emphasis on the effect that the refinement of this process has had on the overall design

Dosimetry intercomparisons in European medical device sterilization plants

An emerging demand for the precise manipulation of cells and particles for applications in cell biology and analytical chemistry has driven rapid development of ultrasonic manipulation technology. Compared to the other manipulation technologies, such as magnetic tweezing, dielectrophoresis and optical tweezing, ultrasonic manipulation has shown potential in a variety of applications, with its advantages of versatile, inexpensive and easy integration into microfluidic systems, maintenance of cell viability, and generation of sufficient forces to handle particles, cells and their agglomerates. This article briefly reviews current practice and reports our development of various ultrasonic standing wave manipulation devices, including simple devices integrated with high frequency (>20 MHz) ultrasonic transducers for the investigation of biological cells and complex ultrasonic transducer array systems to explore the feasibility of electronically controlled 2-D and 3-D manipulation. Piezoelectric and passive materials, fabrication techniques, characterization methods and possible applications are discussed. The behavior and performance of the devices have been investigated and predicted with computer simulations, and verified experimentally. Issues met during development are highlighted and discussed. To assist long term practical adoption, approaches to low-cost, wafer level batch-production and commercialization potential are also addressed