Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "June 2006." Includes bibliographical references. Also available online in PDF format.

This thesis is concerned with the mathematical aspects related to the optimal cutting of an object whose three-dimensional shape has been accurately and robustly reconstructed using appropriately developed computer-vision tools. First, a brief introduction to various one- and two-dimensional packing problems is presented. The Constrained Rectangle Packing problem which allows for defects to be modeled is then formulated and an efficient algorithm for solving it is presented. The two-stage stock-cutting problem according to which a set of rectangular pieces of prespecified dimensions are to be cut from a general shape object with general shape holes or defective regions is then investigated. It is shown how mathematical morphological operators can be vised in order to determine the optimal shifting for a given cutting pattern and proved that the problem of obtaining the optimal cutting pattern is NP-hard. However, the optimal solution to the unconstrained problem using mathematical programming is proposed. For the general problem good sub-optimal solutions are obtained using the technique of simulated annealing. Stereo-vision techniques are then employed for the accurate shape determination of the object to be cut. A three-dimensional reconstruction technique based on projective geometry is formally analysed and guidelines for its robust application are given. Finally, emphasis is placed on the correspondence problem, which becomes very difficult in the case of non-coplanar features and cameras set at 90 degrees from each other. It is shown how to cast the problem into an optimisation framework and a branch and bound algorithm is used in order to obtain the optimal solution. For increased robustness a Hough-Transform-like algorithm is also suggested. Both synthetic and real experimental results are presented throughout the thesis in order to illustrate the validity and usefulness of the proposed algorithms.

This thesis concerns the development of a robotic cell to perform assembly and handling operations on cloth.- A flexible automation approach was adopted, in which the robot was required to control the cloth panel during both handling and sewing operations, without the aid of hard automation attachments which might limit the flexibility of the system. The cell consisted of an adaptively controlled robot, a hierarchy of controllers, a conventional sewing machine, a two-fingered fabric steering end-effector, and several sensor systems. A technique was developed for producing a seam parallel to an edge of arbitrary contour, in which two cameras, a cloth tension sensor and the sewing machine's shaft encoder provided the sensory input. Two sensory servo control systems were required, one control system generated the robot's trajectory to maintain a small constant cloth tension, and the other directed the robot to manipulate the cloth panel to maintain a constant seam width. The design of the cloth tension control was based on the measured frequency response of the open loop system. The seam width control was designed using simulation studies, which accounted for the control transfer function, and nonlinearities such as camera pixel resolution, time delays and robot motion limitations. Several robotic handling techniques were developed, so that a cloth panel placed arbitrarily on the sewing table could be set up for an edge seaming operation, and the cloth could be rotated about the needle. The system's flexibility was demonstrated in the assembly of an irregularly shaped cloth panel, in which three adjacent sides were sewn up.

Self-excited chatter is a basic performance limitation in the machining of metals. Self-excited chatter was investigated both experimenttally and theoretically in the present research. An experimental lathe was constructed so as to obtain orthogonal one degree of freedom cutting. An experimental method developed by Brockley and Ko which enables the recording of a phase plane diagram and the force-velocity curve of one cycle of vibration was used. Experiments were carried out on 70-30 lead free brass workpiece disc with a high speed steel tool at surface speeds ranging from 2 in/sec to 20 in/sec. The results revealed that the force-velocity curve was 'loop' shaped. The chatter vibration was quasi-harmonic and the growth and decay of vibration amplitude with variation in surface speed was observed. Frictional quasi-harmonic vibration was observed to occur in the same speed range which suggested the concept that metal-cutting chatter could be friction actuated. The experimental force-velocity curve was employed in a graphical construction of the phase plane representation of the vibration. The constructed phase plane was in close agreement with the experimental recording. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Muriel is at the pit on the side of road to Glendale describing how her family used to cut peat. This is the first of two of descriptions. Because we had a technical problem we did a description of cutting and stacking the peat again on the way home from Glenadale. Those files are called MurielPeats-2

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Cutting tool edges are honed to an edge radius of about 15-30 micrometers for enhancing tool performance. During honing, defects left by prior manufacturing processes such as grinding and pressing are removed to achieve a higher quality edge. Recently, researchers have shown that tailoring the edge microgeometry to comprise an asymmetric shape and/or a gradient edge microgeometry is beneficial. Conventional edge honing processes such as brush honing and abrasive micro-blasting are limited in terms of reliably generating such geometries in a productive manner. To this end, this research explored the application of non-Newtonian aqueous suspensions of cornstarch and abrasives, for the edge honing of cutting tools. This thesis details the science, technology, characteristics and capabilities of this innovative process. / Thesis / Master of Applied Science (MASc)

Classical orthogonal and oblique cutting are the fundamental material removal or machining processes to which other practical machining processes can be related in the study and modelling of the machining processes. In the last century, a large amount of research and development work has been done to study and understand the various machining processes with a view to improving the processes for further economic (cost and productivity) gains. However, many aspects of the cutting processes and cutting performance remains to be fully understood in order to increase the cutting capability and optimize the cutting processes; in particular, there is little study to understand the effects of the inevitable tool wear on the machining processes. This thesis includes an extensive literature review on the mechanics of cutting analysis. Considerable work has been carried out in past decades on the fundamental analysis of 'sharp' tool cutting. Although some work has been reported on the effects of tool flank wear on the cutting performance, there is a general lack of the fundamental study of the effects of the flank wear on the basic cutting or chip formation process. It has been well documented that tool flank wear results in an increase in the cutting forces. However, it was not known if this force increase is a result of the change in the chip formation process, and/or the rubbing or ploughing forces between the tool flank and the workpiece. In work carried out since the early 1980s, the effects of the so-called edge forces have been considered when the tool is not absolutely sharp. Little has been reported to further develop fundamental cutting theories to understand applications to more relevant the practical situation, i.e. to consider the tool wear effects. Based on the findings of the literature review, an experimental investigation is presented in the first part of the thesis to study the effects of tool flank wear on the basic cutting or chip formation process by examining the basic cutting variables and performance in the orthogonal cutting process with tool flank wear. The effects of tool flank wear on the basic cutting variables are discussed by a comprehensive analysis of the experimental data. It has been found that tool flank wear does not affect the basic cutting variables (i.e. shear angle, friction angle and shear stress). It is therefore deduced that the flank wear does not affect the basic chip formation process in the shear zone and in the tool-chip interface. The study also finds that tool flank wear causes an increase in the total cutting forces, as can be expected and such an increase is entirely a result of the rubbing or ploughing forces on the tool wearland. The significance of this finding is that the well-developed machining theories for 'sharp' tools can be used in modelling the machining processes when tool flank wear is present, rather than study the machining process and develop machining theories from scratch. The ploughing forces can be modelled for incorporation into the overall cutting force prediction. The experimental study also allows for the forces on the wearland (or wearland force) and edge forces to be separated from the total measured forces. The wearland force and edge force models are developed in empirical form for force prediction purpose. In addition, a database for the basic cutting variables or quantities is established for use in modelling the cutting forces. The orthogonal cutting force model allowing for the effects of flank wear is developed and verified by the experimental data. A comprehensive analysis of the mechanics of cutting in the oblique cutting process is then carried out. Based on this analysis, predictive cutting force models for oblique cutting allowing for the effects of flank wear are proposed. The wearland force and edge force are re-considered by analysing the oblique cutting process and the geometrical relation. The predictive force models are qualitatively and quantitatively assessed by oblique cutting tests. It shows that the model predictions are in excellent agreement with the experimental data. The modelling approach is then used to develop the cutting force models for a more general machining process, turning operation. By using the concept of an equivalent cutting edge, the tool nose radius is allowed for under both orthogonal and oblique cutting conditions. The wearland forces and edge forces are taken into consideration by the integration of elemental forces on the tool flank and the cutting edge, respectively. The cutting forces in turning operations are successfully predicted by using the basic cutting quantity database established in the orthogonal cutting analysis. The models are verified by turning operation tests. It shows that the model predictions are in excellent agreement with the experimental results both qualitatively and quantitatively. The major findings, research impacts and practical implications of the research are finally highlighted in the conclusion. The modelling approach considering the flank wear effects in the classical orthogonal and oblique cutting and turning operations can be readily extended to other machining operations, such as drilling and milling.