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Reviewed by V. P. Carey 2 Advances in Thermal Modeling of Electronic Components and System-Vol. 2 is the second in a biannual series which documents recent developments in analysis of the thermal control of electronics. The six chapters of this book are each written by different authors. Each of the first five chapters provides a state-of-the-art review of a different specialized area. Chapter 1 describes recent developments related to air cooling and interconnection heat transmission in minicomputers

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The presently available twist drill grinding machines evolved over a long period of time. They are a product of engineering ingenuity through trial and error. A recently developed mathematical model of twist drill geometry has made it possible to design rationally and to construct a geometrically simple drill grinding machine which provides for the separate and precise specification and adjustment of the important geometry parameters. The machine grinds a conical drill point specified by the four parameters of the model. The conical drill point model can be used to approximate the geometry of hyperboloidal and ellipsoidal drills, and these drills may also be ground on this machine. A microprocessor is used to control the drill grinder. It does the calculations required to convert the drill specifications into the proper positions and movements. It then controls the motion of the machine axes to initiate and complete the grinding process. The result is a machine that is simple mechanically and able to produce a variety of drill points to predetermined specifications.

This paper describes a computer controlled twist drill grinding machine that places a maximum of function in the computer controller making the mechanical part of the machine very simple. A wide variety of conical points can be produced by a virtual rotation about the cone axis accomplished by simultaneous movement of the grinding machine joints.