William Endres

Michigan Technological University | MTU · Department of Mechanical Engineering-Engineering Mechanics

Two e-learning modules are being developed to improve self-regulation and lifelong learning readiness. More than 150 mechanical engineering students completed first versions of the two modules in 2012. An evaluation of the module results suggests that students are learning the module content and tend to enjoy taking the modules. The modules were al...

This project aims to advance personalized learning by helping students to understand and regulate their own learning. The project is designed to equip students with the knowledge, skills, and attitudes of self-directed lifelong learning. We developed two online modules - one on learning styles and the other on motivation. We have begun to test the...

Machining of space age materials like Ti-6Al-4V is associated with thermally activated wear mechanisms which lead to rapid tool failure and increased machine downtime. The high strength and low thermal conductivity of Ti-6Al-4V can reduce tool-life significantly at high cutting speeds adding drastically to the per-unit cost. A new concept, Micro Qu...

Spindle speed variation (SSV) is one of a number of promising strategies to suppress chatter. Most previous research on SSV stability analysis for nonintermittent machining processes has focused on stationary-bar boring or turning. However, nonintermittent rotating-tool machining is also a common process. This paper investigates the effect of SSV i...

Sustainability issues are increasingly important among governments, consumers, and corporations around the world. Many companies are directing their resources to reduce the environmental impact of their products and services. To remain competitive in the global economy, these companies must recruit employees who understand the impact of their decis...

Sustainability issues are increasingly important among governments. consumers, and corporations around the world. Many companies are directing their resources to reduce the environmental impact of their products and services. In order to remain competitive in the global economy, these companies must recruit employees who understand the role of thei...

An added family of stability lobes, which exists in addition to the traditional stability lobes, has been identifiedfor the case of periodically time varying systems. An analytical solution of arbitrary order is presented that identifies and locates multiple added lobes. The stability limit solution is first derived for zero damping where a final c...

Physical experimentation using a kinematically simple straight-edged orthogonal tubeend turning process both verifies the existence of added stability lobes as well as shows good agreement with the analytical solution and numerical simulations of Part 1. The experimental results also verify the added-lobe chatter frequency to be one-half the tooth...

Understanding the effects of tool wear is critical to predicting tool life, the point at which tool performance, in terms of power requirement, dimensional error, surface finish, or chatter, is no longer acceptable. To achieve the long cuts that are required for wear testing while maintaining a clear view of the basic process geometry effects, idea...

Understanding the effects of tool wear is critical to predicting tool life, the point at which tool performance, in terms of power requirement, dimensional error surface finish, burring, or chatter is no longer acceptable. To achieve the long cuts that are required for wear testing while maintaining a clear view of the basic process geometry effect...

For rotating-tool machining, such as milling, line boring, and cylinder boring, the tool rotation causes the machining force on each tooth to rotate repetitively relative to the inertial coordinate frame. This is quite different than stationary-tool machining, such as turning or boring with a stationary boring bar in which the force directions are...

An approach is presented to determine the stability limits for machining processes that exhibit periodic time variation and multi-dimensional structural dynamics. The approach leverages the solution for the single-dimensional case, which identified an added set of stability lobes in addition to those corresponding to the time-invariant case. The so...

A geometric model of the dynamic chip area for processes that employ corner-radiused tools is used to show how the resulting mathematical expressions for overlap factor lead to values outside the traditional range of zero to unity. The mathematical expressions are geometrically interpreted through schematics of the process geometry. The orthogonal...

The use of cutting tools with a honed edge radius to protect the cutting edge from chipping is ever increasing. The basic understanding of the fundamental cutting mechanics in the presence of an edge radius is increasing as well. The present state of knowledge leads one to question how edge-radiused tools behave under conditions that are more pract...

h is well known that the edge geometry of a cutting tool affects the forces measured ill metal cutting. Two experimental methods have been suggested ill the past to extract the ploughing (noncutting) component from the total measured force: (1) the extrapolation approach and (2) the dwell force technique. This study reports the behavior of zinc dur...

It has been proposed that a rough–semi-finish–finish strategy may be possible in the machining of glass and other brittle materials to achieve higher productivity than is realized through either grinding or ductile-mode machining, both of which have been studied extensively to date. A previously presented experimental study of orthogonal glass cutt...

A geometric model of the dynamic chip area for processes that employ corner-radiused tools is used to show how the resulting mathematical expressions for overlap factor lead to values outside the traditional range of zero to unity. The mathematical expressions are geometrically interpreted through schematics of the process geometry. The orthogonal...

Past work on the subject of cutting with a blunt tool has focused mostly on the effect of deformation of the work material and on the process forces. A number of investigators have shown that in orthogonal machining, when the uncut chip thickness approaches the size of the edge radius, size-effect like phenomena greatly influence the forces and sub...

The operation of corner-radiused tools under both depth-of-cut and feed variation is a situation that occurs for many processes (e.g., straight turning, contour turning, boring, and face-milling) and under many practical conditions. A new chip-area expression is formulated by applying a rotational transformation to the chip-area geometry. Results o...

A new, noncontact instrument, based on white light interferometry, is used to measure the edge radii of cutting tools with measurement errors of less than 3 μm. Edges of several commercial cutting inserts are measured and compared. It is found that the radius of the hone varies along the length of the edge in a parabolic manner. The difference betw...

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only incr...

An experimental study of machining glass with a geometrically defined cutting tool is presented. Orthogonal cutting conditions are employed to permit a focus on the fundamental modes of chip and surface formation. Analysis of the machined surfaces under an optical microscope identifies four regimes that are distinctly different with respect to eith...

It is well known that the edge geometry of a cutting tool affects the forces measured during metal cutting. Two experimental methods have been suggested in the past to extract the ploughing (non-cutting) component from the (total) measured force: (1) an extrapolation approach; and (2) a dwell force technique. However, it has been shown that no plou...

An earlier work by the authors presented a solution for the added ultrahigh-speed stability lobe that has been shown to exist for intermittent and other periodically time varying machining processes. That earlier first-order solution was not clearly extendible to a higher order. A more general analytical technique presented here does permit higher-...

This paper presents a mathematical perspective, to complement the intuitive or practice-oriented perspective, to classifying machining operations as parallel-process (simultaneous) or single-process in nature. Illustrative scenarios are provided to demonstrate how these two perspectives may lead in different situations to the same or different conc...

The chipping process in a brittle material subjected to a uniformly applied edge load has been investigated. The present analysis extends earlier work by recognizing that as the chip is formed it may bend and change the loading at the crack tip. This geometry change introduces a nonlinear effect and has significant influence on the phenomenon. The...

This paper presents a detailed mechanistic force analysis that includes size effect for slot milling operations. Existing studies of the milling process have modeled the slot end milling operation as a simple geometric extension of peripheral end milling models with constant values for the specific energies used to predict forces for a given cutter...

A time-domain energy-based analysis is presented as a viable approach to realizing an analytical solution for chatter vibration level. Prediction of chatter vibration level makes it possible to assess a priori the potential damage to equipment should the stability limit be unexpectedly exceeded during process operation. The objective here is to dem...

A cutting-process model addressing the chip removal and edge ploughing mechanisms separately yet simultaneously is presented. The model is developed such that it is readily applicable in an industrial setting, its coefficients have physical meaning, and it can be calibrated with a concise quantity of orthogonal cutting data. The total cutting and t...

The Dual-Mechanism Machining Force Model (DMMFM) developed in Part 1 of this paper is calibrated through a specially developed algorithm, then validated. The calibration results ave used to study the total machining force predictive capabilities of both the traditional lumped shearing model and the DMMFM. It is shown that the Dual-Mechanism Approac...

This paper addresses the computational inefficiency of a new effective lead angle prediction method and its numerical-integration implementation. Two approximations are derived to permit more efficient computation using analytical integration. The first is a small-angle approximation. The second approximation represents the nonlinear uncut thicknes...

The concept of an effective orthogonal cutting edge in turning is considered. The orientation of this edge in the radial-longitudinal plane, as commonly modeled through an effective lead angle, is studied. The methods of effective lead angle prediction used in numerous previously developed force models are plagued with large errors over ranges of p...

A cutting-process model that addresses the shearing and ploughing mechanisms separately yet simultaneously is presented. The model is developed such that it is readily applicable in an industrial setting, its coefficients have physical meaning, and it can be calibrated with a limited quantity of orthogonal cutting data. The total cutting and thrust...

A dynamic model of the cutting force system in the turning process is developed. The model, which describes the dynamic response of the tool holder and workpiece using distributed parameter models, as well as the varying chip geometry and its effects on the cutting forces, can be used to predict the dynamic cutting forces for the turning process. T...

When simulating most industrially used machining processes semi-empirical process force models are often used to relieve the computational burden of other modeling approaches, like FEA or slip-line fields. While the exact forms of these models vary somewhat, they typically model the process force as proportional to the uncut chip area through the s...