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.
Discrete properties of random surfaces
The problem of measuring surface parameters of tribological importance such as peak curvature has been considerably simplified. Using discrete random process analysis tribological parameters of a wide range of surfaces can now be expressed and measured in terms of just two points on the measured autocorrelation function and the r.m.s. value of the surface. In addition, the contribution each ' scale of size ’ of asperity makes to an overall parameter can be assessed quantitatively. Many new expressions relating tribological parameters to the autocorrelation function have been derived using a limiting procedure which produces results entirely consistent with equivalent continuous theory. Using this theory it is now possible to predict ‘gap’ parameters between two surfaces in contact in terms of simple additive parameters of each surface. Finally a new statistical model of the surface has been developed which encompasses many types of engineering surface.