Moshe M. Barash

Complexity in manufacturing systems, Part 1: Analysis of static complexity

This paper studies static complexity in manufacturing systems. We enumerate factors influencing static complexity, and define a static complexity measure in terms of the processing requirements of parts to be produced and machine capabilities. The measure suggested for static complexity in manufacturing systems needs only the information available from production orders and process plans. The variation in static complexity is studied with respect to part similarity, system size, and product design changes. Finally, we present relationships between the static complexity measure and system performance.

Operational control of item flow in versatile manufacturing systems

Analyses of operational control of item flow in versatile manufacturing systems, including control of part-type and mix-ratio, process selection, part entry, and part-to-machine allocation, show significant effects on performance. General principles of operational flow control are indicated.

Experimental investigation on CBN turning of hardened AISI 52100 steel

Abstract This study investigated the performance and wear behavior of different cubic boron nitride (CBN) tools in finish turning of hardened AISI 52100 steel. Tool performance was evaluated based on the part surface finish and the tool flank wear. Wear conditions of CBN cutting tools were primarily characterized by scanning electron microscopy (SEM). Machining results showed that low CBN content tools (CBN-L) consistently perform better than high CBN content counterparts (CBN-H), despite the CBN-L has inferior mechanical properties. The flank wear rates were proportional to cutting speed and CBN-H showed accelerated thermal wear associated with high cutting temperatures. Reducing depth of cut would only improve surface finish to CBN-L, but not to CBN-H, despite similar wear rates. The transferred layer on the flank wear land may result in adhesion of the binder compound and significantly affect the tool wear process. The metallic binder in CBN-H has stronger affinity to the transferred layer and may result in plucking out of CBN particles and consequent severe abrasive wear.

Thermal Effects on the Accuracy of Numerically Controlled Machine Tools

Summary A significant event in the last decade is the merging of electronic information sciences and production control techniques with metrology and manufacturing process into a single integrated system [1]. The advent of computers and sensors has in a sense allowed for the possibility of unmanned manufacturing. While such a goal is desirable, stringent accuracy requirements pose problems. This paper in essence is an overview of some of the work done at Purdue University, W. Lafayette, Indiana [2]. The research attempts to fill a gap between ultra precision engineering which is mastered for example at Lawrence Livermore Laboratory and conventional economic production technology practiced in the US industry [3].

Computer method for investigating the inherent accuracy of centreless grinding

Abstract A method is described for simulating the centreless grinding problem on a digital computer taking into account the geometrical considerations and making an assumption for the elastic deflexion of the machine. Theoretical and experimental results are compared to show the errors produced on work by a sudden infeed. It is also shown that in the case of a uniform infeed, there may be a tendency for regeneration of a waviness to occur with larger values of the included tangents angle β. Without this regeneration the errors produced with a uniform infeed are shown to be extremely small.

Design of a cellular manufacturing system: A syntactic pattern recognition approach

Abstract A syntactic pattern recognition approach is developed for formation of machining cells by classification of machining sequences. There are four steps in this approach: (1) primitive selection, (2) cluster analysis, (3) grammar inference, and (4) syntactic recognition. Tasks of grouping components to form families, identification of suitable manufacturing cells, and assignment of new products to cells are accomplished by means of syntactic pattern recognition techniques. Results obtained by testing this approach on two case problems are presented. Comparison with other techniques indicates that the pattern recognition approach has greater flexibility. Typical advantages are the capability to introduce cost measures which reflect the relative importance of machines as well as the ability to represent the type of material flow being modeled.

Cutting-tool management in computer-integrated manufacturing

The problem of cutting tool management has been brought to the forefront with the emergence of computer-integrated manufacturing (CIM) and, in particular, flexible manufacturing systems (FMSs). The financial and operational ramifications of effective tool management has spurred considerable research in this area during the past decade and many researchers are proposing sound solutions to various facets of this broad-ranging and difficult problem. This paper identifies critical areas of research for the development of tool management systems in CIM. To develop a framework for this, the paper examines and categorizes work in academia and in industry on the management of cutting-tools in CIM and describes some key implementations, particularly in the metal-cutting industry. The solution of manufacturing problems generally demands an eclectic approach, and for this reason, we have tried to taxonomize, describe, and critique the various research thrusts in an attempt to provide a synthesis of use in more unified approaches.

Experimental investigation on cubic boron nitride turning of hardened AISI 52100 steel

Abstract This study investigated the performance and wear behavior of different cubic boron nitride (CBN) tools in finish turning of hardened AISI 52100 steel. Tool performance was evaluated based on the part surface finish and the tool flank wear. Wear conditions of CBN cutting tools were primarily characterized by scanning electron microscopy (SEM). Machining results showed that low CBN content tools (CBN-L) consistently perform better than high CBN content counterparts (CBN-H), despite the CBN-L has inferior mechanical properties. The flank wear rates were proportional to cutting speed and CBN-H showed accelerated thermal wear associated with high cutting temperatures. Reducing depth of cut would only improve surface finish to CBN-L, but not to CBN-H, despite similar wear rates. The transferred layer on the flank wear land may result in adhesion of the binder compound and significantly affect the tool wear process. The metallic binder in CBN-H has stronger affinity to the transferred layer and may result in plucking-out of CBN particles and consequent severe abrasive wear.

Some roundness characteristics of centreless grinding

Abstract Experimental and theoretical results are compared to show that the computer method of Rowe and Barash [1] allows a qualitatively realistic simulation of the centreless grinding process. It is suggested that tendencies of a given centreless grinding geometrical configuration may be conveniently determined by grinding workpieces on which there is a flat. Two workplates are compared with respect to their rounding ability both by the experimental method and by the computer method.

Rule based modeling for planning axisymmetrical deep-drawing

Abstract This paper summarizes contemporary knowledge of deep-drawing axisymmetrical parts in a rule form that can be directly utilized by an automated process-planning procedure. The model is concerned with determining the main operational parameters and the feasibility of metal-flow for given deformation variables. It incorporates empirical formulations, pressworking practice and plasticity knowledge, with the analytic component having priority whenever its validity has been verified. The rules are organized in four categories: “design”, “test”, “rectify” and “compute”. Rules that design the sequence of drawing operations and the specifications of each operation (the sequence and the operations all in hypothesis fashion) are grouped in category I. Category II includes rules that test the validity of each operation. Validity is satisfied if flow stress in every moving zone is reached and the operation is completed without defects. Rules in category III are designated to rectify the design of an unacceptable operation or of unacceptable sequence of operations. Category IV consists of computational rules that make formulation more structured and the search more efficient. An automated reasoning program, controlled by a “Hypothesize and Test-and-Rectify” tactic manipulates the deep-drawing rules to generate a process plan. The input to that system is a CAM representation of the required cup and the output is the sequence of deep-drawing operations that produces it.