Machining stability and machine tool dynamics

Machining is a common manufacturing process in industry due to its high flexibility and ability to produce parts which excellent quality. The productivity and quality in machining operations can be limited by several process constraints one of which is the self-excited chatter vibrations. Under certain conditions, the process may become unstable yielding oscillations with high amplitudes which result in poor surface finish and damage to the cutting tool, part and the machine tool itself. Stability analysis of the dynamic cutting process can be used to determine chatter-free machining conditions with high material removal rate. Since chatter is a result of the dynamic interactions between the process and the structures both cutting and machine tool dynamics are important elements of the stability analysis. In this paper, methods developed for stability analysis of cutting processes and machine tool dynamics will be presented. Implications of these methods in the selection of process parameters and machine tool design will be also discussed with example applications

An analytical design method for milling cutters with nonconstant pitch to increase stability, part 2: Application

Chatter stability in milling can be improved significantly using variable pitch cutters. The pitch angles can be optimized for certain chatter frequency and spindle speed ranges using the analytical method presented in the first part of this two-part paper. In this part, the improvement of productivity and surface finish are demonstrated in three example applications. It is shown that chatter stability can be improved significantly even at slow cutting speeds by properly designing the pitch angles. A roughing example demonstrates substantially reduced peak milling forces which allows higher material removal rate

Harman on Mental Paint and the Transparency of Experience

Harman famously argues that a particular class of antifunctionalist arguments from the intrinsic properties of mental states or events (in particular, visual experiences) can be defused by distinguishing “properties of the object of experience from properties of the experience of an object” and by realizing that the latter are not introspectively accessible (or are transparent). More specifically, Harman argues that we are or can be introspectively aware only of the properties of the object of an experience but not the properties of the experience of an object and hence that the fact that functionalism leaves out the properties of the experience of an object does not show that it leaves out anything mentally relevant. In this paper, I argue that Harman’s attempt to defuse the anti-functionalist arguments in question is unsuccessful. After making a distinction between the thesis of experiencing-act transparency and the thesis of mental-paint transparency, (and casting some doubt on the former,) I mainly target the latter and argue that it is false. The thesis of mental-paint transparency is false, I claim, not because mental paint involves some introspectively accessible properties that are different from the properties of the objects of experiences but because what I call the identity thesis is true, viz. that mental paint is the same as (an array of) properties of the object of experience. The identification of mental paint with properties of the object of experience entails that the antifunctionalist arguments Harman criticizes cannot be rightly accused of committing the fallacy of confusing the two

Analytical models for high performance milling. Part II: process dynamics and stability

Chatter is one of the most important limitations on the productivity of milling process. In order to avoid the poor surface quality and potential machine damage due to chatter, the material removal rate is usually reduced. The analysis and modeling of chatter is complicated due to the time varying dynamics of milling chatter which can be avoided without sacricing the productivity by using analytical methods presented in this paper