THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

This paper presents an overview of the recent advances in high performance cutting of aerospace alloys and composite currently used in aeroengine and aerostructure applications. Progress in cutting tool development and its effect on tool wear and surface integrity characteristics of difficult to machine materials such as nickel based alloys, titanium and composites is presented. Further, advances in cutting technologies are discussed, focusing on the role of hybrid machining processes and cooling strategies (MQL, high pressure coolant, cryogenic) on machining performance. Finally, industrial perspectives are provided in the context of machining specific components where future challenges are discussed.

High performance cutting of advanced aerospace alloys and composite materials

Delamination formation, evaluation and suppression during drilling of composite laminates: A review

Ceramic matrix composites (CMC) are enabling materials for a number of high-temperature and demanding applications in aerospace, power generation, ground transportation, nuclear, environmental, and chemical industries. Tremendous progress has been made in technology development, manufacturing, commercialization, and applications of CMC over the last few years. However, significant challenges (such as the lack of specifications, databases, and in-service repair methodology, and high machining cost) still remain for their widespread applications. In this paper, rotary ultrasonic machining (RUM) is introduced into drilling holes on CMC panels for the first time. The feasibility to machine CMC using RUM is investigated. Cutting forces and material removal rates (MRR) are compared for machining of CMC with and without ultrasonic vibration and for two types of CMC materials and one typical advanced ceramic material (alumina). Chippings at the hole exit are also observed under a microscope. Furthermore, the paper presents the results of a designed experimental investigation into RUM of CMC. A three-variable two-level full factorial design is employed to reveal main effects as well as interaction effects of three RUM process parameters (spindle speed, feedrate, and ultrasonic power). The process outputs studied include cutting force, MRR, and hole quality (in terms of chipping dimensions).

Rotary ultrasonic machining of ceramic matrix composites: feasibility study and designed experiments

Disclosed herein is a lens driving device which is able to increase displacement without restriction, does not require a complex structure despite having a low power consumption, solves problems of friction and noise occurring in a gear mechanism, and realizes miniaturization and lightness. The lens driving device of the present invention includes a substrate which generates surface acoustic waves on a surface thereof, and a movable unit which is coupled to an optical lens and executes translation above the substrate using the surface acoustic waves. Therefore, the lens driving device of the present invention can implement translation of a lens without a separate mechanism, unlike conventional driving devices using motors and screws. Furthermore, the present invention satisfies the recent trend towards miniaturization and lightness, thus being usable in a variety of industrial fields that use optical lenses.

Lens driving device

Ultrasonic drilling of two-dimensional carbon fiber-reinforced silicon carbide(C/SiC) composites was investigated in this study. The composites were made through a polymer pyrolysis route. X-ray diffraction was adopted to examine the formation of crystalline structure in the matrix of the fabricated composites. Density and porosity, and flexural strength were measured to study the densification efficiency and the mechanical properties, respectively, of the C/SiC composites fabricated under various conditions. The fracture morphologies were also examined by scanning electron microscopy to investigate the fracture behavior of the composites under flexural test. The effects of various parameters of ultrasonic drilling, including abrasives, volume ratio, electric current and down-force, on the material removal rate, hole clearance, edge quality and tool wear are presented and discussed. Optimal operating conditions are identified. In comparison with other feasible machining processes, ultrasonic drilling for this composite material possesses advantages concerning machinability and cost.

Assessment of ultrasonic drilling of C/SiC composite material

When designing an auto-focusing actuator for use in cell phone cameras, it is essential to minimize the device size, maximize the positioning repeatability, and minimize the power consumption. In a previous study, we presented a miniature auto-focusing voice coil motor (VCM) actuator for cell phone camera applications in which the lens was precisely positioned by a closed-loop feedback signal generated by a Hall element. Our study characterizes the performance of this device by using an experimental approach. The results show that the proposed actuator is not only smaller than a conventional VCM actuator with an open-loop positioning system, but also has improved positioning repeatability, a more rapid response, and lower power consumption.

Design and Characterization of Miniature Auto-Focusing Voice Coil Motor Actuator for Cell Phone Camera Applications

Design and experimental verification of novel six-degree-of freedom geometric error measurement system for linear stage

In keeping with consumer preferences for ever smaller electronic products, a requirement exists for compact, high-performance auto-focusing actuators for the camera modules deployed in cell phones. Accordingly, the present study proposes a miniaturized electromagnetic-based actuator comprising a voice coil motor (VCM) and a closed-loop position control system in which an auto-focusing capability is achieved by using a position feedback signal generated by a Hall element to dynamically adjust the position of the lens module. The experimental results show that the holding current required to maintain a lens module weighing 200 mgw in the vertical position is 17 mA +/- 2 mA. Compared to conventional VCM actuators deployed in cell phone camera applications, the actuator presented in this study has a smaller size (6.5 mm x 6.5 mm x 4 mm) and an improved power efficiency. In particular, the miniaturized actuator reduces the holding current required to maintain the lens module in the focusing position by around 75% of that required in a traditional actuator.

A miniaturized low-power VCM actuator for auto-focusing applications.

As a foundation to enhance the machining accuracy of five-axis machine tools, a robust, efficient, and precise method to measure the location errors of rotary axes on five-axis machine tools has been proposed in this study. This precise identification and calibration methodology for on-machine measurement of location errors of rotary axes is achieved by using a touch-trigger probe and a precise sphere installed on a tilting rotary table. Compared to commercially available devices, such as the double ball bar and R-test, the proposed measurement method has the advantages of efficient and automated calibration procedures in each periodical measurement. This proposed calibration algorithm builds a kinematic error model and measurement equations by using a forward and inverse kinematic approach and estimates the location errors by applying the least squares method. Moreover, the proposed calibration algorithm defines the location errors of the two rotary axes so they can be estimated and separated individually to avoid coupling effects. All the location errors of the rotary axes measured using the proposed measurement method were identified after compensation to improve the accuracy of the five-axis machine tool. A simulation was implemented to inspect the influence of uncertainties on the identified location errors of the rotary axes. Finally, an experimental demonstration on a five-axis machine tool with a tilting rotary table validates the feasibility of the proposed measurement method.

Chien-Sheng Liu

Papers

Assessment of ultrasonic drilling of C/SiC composite material

Design and Characterization of Miniature Auto-Focusing Voice Coil Motor Actuator for Cell Phone Camera Applications

Design and experimental verification of novel six-degree-of freedom geometric error measurement system for linear stage

A miniaturized low-power VCM actuator for auto-focusing applications.

Identification and verification of location errors of rotary axes on five-axis machine tools by using a touch-trigger probe and a sphere