Effect of cutting speed on surface quality by bandsawing
The surface profile behavior of workpieces sawn has been investigated. Six species were sawn under the condition of four different kinds of cutting speed by the band saw. The real surface profile of a sawn workpiece is composed of two sections, which are the additivity of the waviness of filtered wave and roughness curve. The roughness of center line average as well as amplitude decrease with the increasing of cutting speed for different kinds of species used in the experiment.
Description of roughness profiles by separating the random and periodic components
Abstract The probability that it is not possible to obtain a significant description of roughness profiles composed of random and periodic components by using statistical methods is discussed. It is shown that the random and periodic components can be separated by using the frequency spectrum and the autocorrelation function of the profile. The physical significance of the separate components is discussed and it is shown that it is possible to describe a long crested surface by a single profile using these components The method of separating the random and periodic components allows a parametrical description of the roughness profile to be given. It is then possible to use these parameters to calculate a synthetic signal sign with the same basic properties as the measured profile.
Thermal conductance of a rough elastic contact
From an existing theory of the elastic contact of an isotropically rough Gaussian surface in terms of moments of its power spectrum, limiting expressions for the number and average size of contact spots are derived and hence an upper-bound expression for the solid thermal contact conductance is obtained in terms of the separation of the contacting surfaces. It is shown that over a realistic range of loads, conductance and number of contacts are approximately proportional to the load and contact size is almost independent of load. Equivalent moments are defined such that the geometry of anisotropic surfaces can be represented by equivalent isotropic equations in good agreement with experiment. The problems of quantifying the moments are discussed and it is shown how equivalent moments may be obtained from simple measurements on two profiles at right angles.