Showing papers in "Robotics and Computer-integrated Manufacturing in 2002"
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TL;DR: In this article, a neural network modeling approach is presented for the prediction of surface roughness (Ra) in CNC face milling using the Taguchi design of experiments (DoE) method.
Abstract: In this paper, a neural network modeling approach is presented for the prediction of surface roughness (Ra) in CNC face milling The data used for the training and checking of the networks’ performance derived from experiments conducted on a CNC milling machine according to the principles of Taguchi design of experiments (DoE) method The factors considered in the experiment were the depth of cut, the feed rate per tooth, the cutting speed, the engagement and wear of the cutting tool, the use of cutting fluid and the three components of the cutting force Using feedforward artificial neural networks (ANNs) trained with the Levenberg–Marquardt algorithm, the most influential of the factors were determined, again using DoE principles, and a 5×3×1 ANN based on them was able to predict the surface roughness with a mean squared error equal to 186% and to be consistent throughout the entire range of values
437 citations
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TL;DR: Simulated annealing (SA), a meta-heuristic, is employed in this study to determine a scheduling policy so as to minimize total tardiness, and shows that the proposed SA method significantly outperforms a neighborhood search method in terms of total tardyness.
Abstract: This paper presents a scheduling problem for unrelated parallel machines with sequence-dependent setup times, using simulated annealing (SA). The problem accounts for allotting work parts of L jobs into M parallel unrelated machines, where a job refers to a lot composed of N items. Some jobs may have different items while every item within each job has an identical processing time with a common due date. Each machine has its own processing times according to the characteristics of the machine as well as job types. Setup times are machine independent but job sequence dependent. SA, a meta-heuristic, is employed in this study to determine a scheduling policy so as to minimize total tardiness. The suggested SA method utilizes six job or item rearranging techniques to generate neighborhood solutions. The experimental analysis shows that the proposed SA method significantly outperforms a neighborhood search method in terms of total tardiness.
233 citations
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TL;DR: In this article, a successful attempt has been made to develop an EMM setup for carrying out in depth independent research for achieving satisfactory control of electrochemical machining process parameters to meet the micromachining requirements.
Abstract: A better understanding of high rate anodic dissolution processes is urgently required for electrochemical micromachining (EMM) to become a widely employed manufacturing process in the electronic and precision manufacturing industries particularly in the micromanufacturing domain. A successful attempt has been made to develop an EMM setup for carrying out in depth independent research for achieving satisfactory control of electrochemical machining process parameters to meet the micromachining requirements. The developed EMM setup mainly consists of various sub-components and systems, e.g., mechanical machining unit, microtooling system, electrical power and controlling system and controlled electrolyte flow system, etc. All these system components are integrated in such a way that the developed EMM system setup will be capable of performing basic and fundamental research in the area of EMM fulfilling the requirements of micromachining objectives.
141 citations
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TL;DR: This paper demonstrates how the value stream mapping (VSM) suite of tools can be used to map the current state of a production line and design a desired future state and provides a roadmap for how VSM can provide necessary information for analysis of equipment replacement decision problems encountered in lean manufacturing implementation.
Abstract: Traditional manufacturing systems are built on the principle of economies of scale. Here, the large fixed costs of production are depreciation-intensive because of huge capital investments made in high-volume operations. These fixed costs are spread over large production batch sizes in an effort to minimize the total unit costs of owning and operating the manufacturing system. As an alternative to “batch-and-queue,” high-volume, and inflexible operations, the principles of the Toyota Production System (TPS) and lean manufacturing have been widely adopted in recent years in the US [1] , [2] , [3] , [4] . In this paper, we illustrate an equipment replacement decision problem within the context of lean manufacturing implementation. In particular, we demonstrate how the value stream mapping (VSM) suite of tools can be used to map the current state of a production line and design a desired future state. Further, we provide a roadmap for how VSM can provide necessary information for analysis of equipment replacement decision problems encountered in lean manufacturing implementation.
141 citations
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TL;DR: In this article, a new methodology for key performance indicators (KPIs) in manufacturing companies is presented and a critical evaluation and short examples of applying them are included, with the main conclusion that the KPIs can be used quantitatively in assessing the manufacturing performance of a company.
Abstract: This paper sets out the basis to establish key performance indicators (KPIs) in manufacturing companies. Their significance and how they can be used to make improvements. KPIs has been chosen in order to deal with the possibility of improving the utilization of a process manufacturing plant. The objective is to present a new methodology for KPIs. Also methodologies on manufacturing performance measures taken from the literature are used for the solution of improving the utilization. They are discussed on the basis of a manufacturing experience. In this paper, a presentation of these methodologies, a critical evaluation and short examples of applying them are included. The main conclusion of this paper is that the KPIs can be used quantitatively in assessing the manufacturing performance of a company.
135 citations
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TL;DR: In this paper, a reverse engineering system for rapid modeling and manufacturing of products with complex surfaces is presented, which consists of three main components: a 3D optical digitizing system, a surface reconstruction software and a rapid prototyping machine.
Abstract: This paper presents a reverse engineering system for rapid modeling and manufacturing of products with complex surfaces. The system consists of three main components: a 3D optical digitizing system, a surface reconstruction software and a rapid prototyping machine. The unique features of the 3D optical digitizing system include the use of white-light source, and cost-effective and quick image acquisition. The surface reconstruction process consists of three major steps: (1) range view registration by an iterative closed-form solution, (2) range surface integration by reconstructing an implicit function to update the volumetric grid, and (3) iso-surface extraction by the Marching Cubes algorithm. The modeling software exports models in STL format, which are used as input to an FDM 2000 machine to manufacture products. The examples are included to illustrate the systems and the methods.
117 citations
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TL;DR: An assembly planner, based upon an enhanced genetic algorithm, is presented that demonstrates improved searching characteristics over an assembly planner based upon a traditional genetic algorithm.
Abstract: Automated assembly planning reduces manufacturing manpower requirements and helps simplify product assembly planning, by clearly defining input data, and input data format, needed to complete an assembly plan. In addition, automation provides the computational power needed to find optimal or near-optimal assembly plans, even for complex mechanical products. As a result, modern manufacturing systems use, to an ever greater extent, automated assembly planning rather than technician-scheduled assembly planning. Thus, many current research reports describe efforts to develop more efficient automated assembly planning algorithms. Genetic algorithms show particular promise for automated assembly planning. As a result, several recent research reports present assembly planners based upon traditional genetic algorithms. Although prior genetic assembly planners find improved assembly plans with some success, they also tend to converge prematurely at local-optimal solutions. Thus, we present an assembly planner, based upon an enhanced genetic algorithm, that demonstrates improved searching characteristics over an assembly planner based upon a traditional genetic algorithm. In particular, our planner finds optimal or near-optimal solutions more reliably and more quickly than an assembly planner that uses a traditional genetic algorithm.
90 citations
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TL;DR: This paper extends the already published set of design rules considerably with the rules based on practical experiences from more than 60 set-up reduction projects in different industries over the last 10 years, strongly believing that the responsibility of the equipment designer goes beyond these technical aspects.
Abstract: The importance of short set-up times is becoming more and more important in every type of industry nowadays. How to address this problem is already known for about 20 years. The SMED method, originally developed by the Japanese Industrial Engineer Shigeo Shingo for reducing the time to exchange dies, gives a really straightforward approach to improve existing set-ups and to easily obtain a reduction of up to 90%, with mostly a moderate investment. In these past decade, several people have also realized that instead of improving an “a posteriori” situation, a lot of problems can be prevented during the design phase of the equipment. Only a few authors proposed design rules. These rules generally have a technical or engineering point of view. In several cases, the authors have noted that, even for a brand new equipment, the design can still be improved substantially. This paper extends the already published set of design rules considerably with the rules based on practical experiences from more than 60 set-up reduction projects in different industries over the last 10 years. In addition, the authors strongly believe that the responsibility of the equipment designer goes beyond these technical aspects. An efficient and effective set-up method also needs to be designed. Several basic industrial engineering tools can be used to this end.
89 citations
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TL;DR: The program is a rule based expert system, and recommends the RP system along with its full specifications on the basis of interactive question–answer session with the user, believed to be the first expert system based RP selection program.
Abstract: The availability of a growing number of rapid prototyping (RP) systems with wide ranging capabilities has created a problem of selecting an appropriate RP system for industry as well as educational sector to suit their requirements. This paper presents an expert system based RP system selection program incorporating 39 RP systems commercially available from 21 RP manufacturers worldwide. The program allows the user to choose one of the four options, namely, quick selection, detailed selection, build technology or machine style for system selection, with each option considering a systematic selection criteria. The program is a rule based expert system, and recommends the RP system along with its full specifications on the basis of interactive question–answer session with the user. The system is believed to be the first expert system based RP selection program and has the potential for future expansion into a full-fledged RP selector system.
87 citations
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TL;DR: In this paper, an expert system has been developed to act as a mediator between the program and interested organizations, given some simple quantitative data on manufacturing performance, the expert system can estimate the organization's complexity and suggest some recommendations to reduce it, based on the data provided by the organization.
Abstract: Information-theoretic modelling of manufacturing organizations and their supply chains has led to the development of measures of manufacturing complexity. The measures include assessment of the structural, dynamic and decision-making complexity associated with the processing and movement of material and information around a manufacturing system. A computer program has been written to calculate the decision-making complexity of a manufacturing system, under different system layouts and operating characteristics. In order to make the results of this program accessible to manufacturing organizations, an expert system has been developed to act as a mediator between the program and interested organizations. Given some simple quantitative data on manufacturing performance, the expert system can estimate the organization's complexity and suggest some recommendations to reduce it, based on the data provided by the organization. The expert system will be implemented on the web to enable on-line acquisition and searching of data on companies. The quid pro quo of the expert system is that anonymized data on the organizations will be retained so that complexity benchmarks may be established.
72 citations
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TL;DR: In this article, a state space variation propagation model is derived from the product and process design information, and the virtual machining concept is applied to isolate faults between operations, and further used in the root cause determination.
Abstract: It is a very challenging task to develop effective process control methodologies for multi-operational manufacturing processes. Although Statistical Process Control (SPC) has been widely used as the primary method in the control of quality, it mainly serves as a change detection tool rather than a method to identify root causes of process changes. This paper proposes a systematic approach to overcome the limitations faced by SPC. In this method, a state space variation propagation model is derived from the product and process design information. The virtual machining concept is applied to isolate faults between operations, and further used in the root cause determination. The detailed methodology is presented, and a case study is conducted to illustrate and verify the developed diagnosis method. r 2002 Elsevier Science Ltd. All rights reserved.
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TL;DR: The structure of CAD/CAM integrated system is presented, then, key technologies related to realize CAD-CAM integration are discussed in detail and finally main functions and an application case of CAD/(CAM) integrated system are introduced.
Abstract: For virtual enterprises to realize efficient operation in the 21st century, it is necessary to develop an environment that can support collaborative work of multi-disciplinary groups distributed in different places. CAD/CAM integrated system is an important subsystem in this environment. In this paper, the structure of CAD/CAM integrated system is presented, then, key technologies related to realize CAD/CAM integration are discussed in detail and finally main functions and an application case of CAD/CAM integrated system is introduced.
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TL;DR: In this article, the authors address a major issue in fixture layout design to determine and evaluate the acceptable fixture designs based on multiple quality criteria and to select an optimal fixture with appropriate trade-offs among multiple performance requirements.
Abstract: This paper addresses a major issue in fixture layout design to determine and evaluate the acceptable fixture designs based on multiple quality criteria and to select an optimal fixture with appropriate trade-offs among multiple performance requirements. The performance objectives considered are related to the fundamental requirements of kinematic localization and total fixturing (form-closure). Three performance objectives are defined as the workpiece localization accuracy and the norm and dispersion of the locator contact forces. The paper focuses on multi-criteria optimal design with a hierarchical approach. An efficient interchange algorithm is extended and used for different practical cases, leading to proper trade-off strategies for performing fixture synthesis. Examples are given to illustrate empirical observations with respect to the proposed approach and its effectiveness.
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TL;DR: A selective perception based approach to visual processing is presented that instead of processing the whole image, only areas that are deemed ‘‘interesting’’ and hence calling for attention are analyzed and constructed.
Abstract: Many industrial applications require some sort of automated visual processing and classification of items placed on a moving conveyor. In this paper, we present a selective perception based approach to visual processing. The novelty of this approach is that instead of processing the whole image, only areas that are deemed ‘‘interesting’’ and hence calling for attention are analyzed. The attentional sequences thus constructed can then be used for a variety of tasks including shape determination. Since only a small portion of the whole image is processed, visual processing can be real-time and flexible without requiring special hardware. Two different applications based on this approach are described. In a defective item detection task, we explain in detail how attentional sequences can be used. As a second application, the approach has been implemented in an automated remote controller sorter in a TV manufacturing plant—thus confirming its practical applicability.
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TL;DR: In this paper, the necessary and sufficient condition for form-closure fixturing is derived and two quantitative indices, one to minimize the sum of all normal contact forces and the other to minimize maximum normal contact force, are presented.
Abstract: Form-closure is considered as a purely geometric property of a set of unilateral contact constraints such as those applied on a workpiece by a mechanical fixture. This paper provided qualitative analysis of form-closure fixturing. The necessary and sufficient condition for form-closure fixturing is derived. Some fundamental problems related to form-closure are solved such as minimum number of frictionless contact points and the way to arrange them to achieve form-closure. On the basis of qualitative analysis, the quantitative evaluation of form-closure is investigated. To assess quantitatively the form-closure fixturing, two quantitative indices, one to minimize the sum of all normal contact forces and the other to minimize the maximum normal contact force, are presented. Finally, the given example verifies the analysis method and evaluating indices.
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TL;DR: In this article, a software system is developed to assist Cubital operators to layout CAD models with various geometric shapes using simulated annealing techniques, which is suitable for building multiple parts with different geometry and dimensions in batch production of rapid prototypes to minimize the cost of prototypes.
Abstract: Rapid prototyping technologies are capable of directly manufacturing physical objects from CAD models and have been increasingly used in product development, tool and die making and fabrication of functional parts. Solid ground curing (SGC) technology, one of the rapid prototyping technologies, is suitable of building multiple parts with different geometry and dimensions in batch production of rapid prototypes to minimize the cost of prototypes. However, the layout of CAD models in a graphic environment is time-consuming. Because of high cost of the resin, the layout of models in a batch is critical for the success of the SGC operations in any industrial environment. This paper presents the layout optimization using simulated annealing techniques. A software system was developed to assist Cubital operators to layout CAD models with various geometric shapes. The system accepts STL files from any solid modeling environment. Several examples are provided to illustrate the techniques and effectiveness of the approach.
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TL;DR: In this paper, a rotary-bar driven by an electric motor is mounted to the arm of a robot having six degrees of freedom in order to give an arbitrary position and attitude to the tool.
Abstract: The study deals with the automatic chamfering for the case of hole on free-curved surface on the basis of CAD data, using an industrial robot. As a chamfering tool, a rotary-bar driven by an electric motor is mounted to the arm of the robot having six degrees-of-freedom in order to give an arbitrary position and attitude to the tool. The robot control command converted from the chamfering path is transmitted directly to the robot. From the experimental results, the system is found effective to remove a burr along the edge of a hole on a workpiece with free-curved surface.
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TL;DR: Methods are being developed to streamline the development of a simplified process for computer based task analysis and to place the emphasis on good design and ergonomics principles as opposed to ‘driving’ the system.
Abstract: The ‘design for all’ philosophy promotes the development of products that meet the requirements of a broader section of the population, including those who are older or disabled, to minimise the need for bespoke designs and individual customisations. Such an approach begins to meet the needs of a population containing an ever increasing proportion of these excluded groups, whilst providing opportunities to manufacturers to maximise the available market for any given product. Most design activity embodies some form of task analysis that involves identifying users and the tasks they perform. Computer based human modelling systems are becoming increasingly important in this task analysis role combined with the established ergonomics technique of fitting trials, in which a product or environment is evaluated through trials using a carefully selected user group. This research addresses the lack of existing data necessary for the accurate representation of human form and capability in the older and disabled populations for use in these modelling systems. A small-scale survey is being undertaken to collect this important information. In addition, existing modelling systems in this area rely on expert ergonomics knowledge in performing task based analysis, which in addition can be a time consuming and repetitive task. Methods are being developed to streamline this process and to place the emphasis on good design and ergonomics principles as opposed to ‘driving’ the system. These methods involve the development of a simplified process for computer based task analysis and a means of determining the percentage accommodated by any given design. Further research will eventually focus on extending the data collection, refining the task model and look at a means of suggesting design solutions in response to the analysis results.
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TL;DR: In this article, an analytical multi-objective framework for concurrent design of product and processes is presented to simultaneously consider the tolerance specification on the product or component dimensions along with the selection of the manufacturing processes.
Abstract: In this paper we present an analytical multi-objective framework for the concurrent design of product and processes. The objective is to simultaneously consider the tolerance specification on the product or the component dimensions along with the selection of the manufacturing processes. For this purpose we consider three objectives: to minimize unit cost, to minimize quality loss and to minimize manufacturing lead time. We characterize the properties of the non-dominated solutions. These solutions provide flexibility needed in an agile manufacturing environment. The min–max approach is used to obtain trade-off solutions.
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TL;DR: The described technique incorporates the analytic hierarchy process and linear goal programming into the process of evaluating alternatives for sub-components and parts, which enables the design of products by satisfying customer, technical, and financial requirements.
Abstract: In this paper, a sub-component selection methodology for product design is described. The described technique incorporates the analytic hierarchy process and linear goal programming into the process of evaluating alternatives for sub-components and parts, which enables the design of products by satisfying customer, technical, and financial requirements. Also, an additional comparison technique for comparing sub-component alternatives is developed, called “scoring matrix”. In this technique, pair-wise comparisons are performed within one matrix for all possible criteria to measure the strength of one-to-one relationship between sub-component alternatives. This technique is more appropriate than traditional analytical hierarchy process in addressing problems such as the comparison of sub-component alternatives. An illustrative example demonstrates the application of our methodology to the design of a computer system.
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TL;DR: In this paper, a real good approach for a computer-aided assembly (CAA) system, which makes use of software agent technology and deals with a representation of assembly features, is proposed.
Abstract: This paper proposes a real good approach for a computer-aided assembly (CAA) system, which makes use of software agent technology and deals with a representation of assembly features. The context of our work is the study of the engineering and manufacturing system based on the assembly features. The system never thinks like an assembly engineer, but makes it possible to support engineers in doing creative methodology, and producing new ideas better than the conventional CAA.
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TL;DR: In this paper, a method is proposed which generates bending sequences of a sheet metal part handled by a robot, and the best grasping positions for each bending and the number of repositions must be indicated in advance.
Abstract: In the present study, a method is proposed which generates bending sequences of a sheet metal part handled by a robot. If parts are handled by a robot, the best grasping positions for each bending and the number of repositions must be indicated in advance. Using the proposed method, feasible bending sequences with grasping positions are obtained and the sequences are sorted in the order of the number of repositions. In generating the sequences, several important features for the sheet metal bending are considered by dividing them into channels, which is one of the base features. The error accumulated during bending operation is calculated for each sequence, and set-up positions can be selected so as to satisfy the preferential tolerance. The proposed method assists the sheet metal process planner by allowing him/her to plan in advance the best bending sequences and to confirm if the robot can perform the handling operation. A computer simulation was written based on the proposed method, and illustrative examples and results of various simulation models are also given.
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TL;DR: In this article, an integer programming formulation is presented to determine optimal purchase, salvage, utilization, and storage decisions for each asset over a finite horizon, and valid inequalities to improve the lower bound provided by the linear programming relaxation and a dynamic programming approach to provide initial upper bounds.
Abstract: Traditional equipment replacement models focus on single machine problems. However, the capacity of many production facilities is defined by multiple, heterogeneous machines. In this situation, optimal replacement (and expansion) decisions must consider all machines and their integration simultaneously as they define system capacity and are therefore economically interdependent. We model a multiple machine replacement problem that is characterized as a parallel flow shop environment. Work flows through processes in a facility according to a predetermined processing order for the product(s). For a given process, numerous machines, which may differ according to type (different manufacturers), capacity, and/or age, operate in parallel. A series of these processes defines a line and in our analysis, a plant is comprised of multiple, parallel lines. In this preliminary investigation, we present an integer programming formulation to determine optimal purchase, salvage, utilization and storage decisions for each asset over a finite horizon. We illustrate that this model is difficult to solve. We provide valid inequalities to improve the lower bound provided by the linear programming relaxation and a dynamic programming approach to provide initial upper bounds.
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TL;DR: The development of a Fuzzy Genetic Optimization algorithm, an object-oriented library to handle fuzzy rules optimization with genetic optimization, and the effect of constraint rules are presented and discussed.
Abstract: Fuzzy rules optimization is always a problem for a complex fuzzy model. For a simple 2-inputs-1-output fuzzy model, the designer has to select the most optimum set of fuzzy rules from more than 10 000 combinations. The authors have developed fuzzy models for machinability data selection (Int. J. Flexible Autom. Integrated Manuf. 5 (1 and 2) (1997) 79). There are more than 2×10 29 possible sets of rules for each model. The situation would be more complicated if there were a further increase in the number of inputs and/or outputs. The fuzzy rules (Turning Handbook of High-Efficiency Metal Cutting, General Electric Co., Detroit) were selected based on trial and error and/or intuition. Genetic optimization has been suggested in this paper to further optimize the fuzzy rules. The development of a Fuzzy Genetic Optimization algorithm is presented and discussed. An object-oriented library to handle fuzzy rules optimization with genetic optimization has been developed. The effect of constraint rules is also presented and discussed. Comparisons between the results from the optimized models and literature are made.
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TL;DR: In this article, a manufacturing system was modelled using different levels of detail, including high level of detail and aggregation of some of the processes in the system and the third level consisting only of the main processes.
Abstract: Modelling and simulating manufacturing systems often involves several different organisational units This can make data collection difficult and it can be hard to obtain data that allows for the model to be built with a consistent level of detail To investigate the impact of a varying level of detail, a manufacturing system was modelled using different levels of detail The first model was modelled at a high level of detail containing all elements in the system The second model was an aggregation of some of the processes in the system and the third model consisted only of the main processes The experiments performed with the models, aimed at finding differences between models' outputs that originated from the choice of the level of detail The results show that there are significant differences between the models The simulation models used for this paper are made in collaboration with a company in the mobile communications industry and deals with supply chain problems
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TL;DR: The paper describes the derivations involved in the determination of view parameters when the information of the angles of pan/tilt rotation of the cameras is available, and enables adequate parameter observability with a greatly reduced sampling in terms of number and breadth.
Abstract: The successful implementation of close-tolerance, three-dimensional rigid body assembly has been robustly achieved using camera-space manipulation in a limited region of the manipulator's workspace. The extension of this capability to a broader region can in general be achieved by mounting the cameras on computer-controlled platforms or “pan/tilt” units. The use of this type of platform enables the encompassing of a large physical region within the fields of view of the cameras, while preserving an approximately constant image-plane resolution per unit physical space. The paper describes the derivations involved in the determination of view parameters when the information of the angles of pan/tilt rotation of the cameras is available. Such procedure enables adequate parameter observability with a greatly reduced sampling in terms of number and breadth. Practical considerations for the implementation of this capability for a high-precision, three-dimensional task across a large workspace region are also presented.
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TL;DR: In this article, a conceptual model of a placement time estimator function is constructed for turret style surface mount technology (SMT) placement machines, and empirical data is then used to develop the estimator functions for the Fuji CP4-3 machine.
Abstract: Efficiently placing printed circuit board (PCB) components is critically important in the highly competitive electronics industry. Previous research has focused on algorithms to determine feeder arrangement and placement sequencing for placement machines. However, consistent machine models do not exist that can be used to compare the results of these algorithms. A conceptual model of a placement time estimator function is constructed for turret style surface mount technology (SMT) placement machines. Empirical data is then used to develop the estimator function for the Fuji CP4-3 machine. Results for eight commercial PCB designs indicate that there is no statistical difference between the actual and the estimated placement times. Thus, the placement time estimator function developed in this research provides an accurate method to estimate component placements times on a PCB by a Fuji CP4-3. The placement time estimator function presented here can be used as part of a computer integrated manufacturing system to facilitate process planning and improve cycle time estimates for production planning purposes.
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TL;DR: In this paper, a study was performed in a rough mill collecting data on the errors made by humans when marking defects and computer-based simulation tools were used to assess the significance of these errors.
Abstract: Rough sawn, kiln-dried lumber contains characteristics such as knots and bark pockets that are considered by most people to be defects. When using boards to produce furniture components, these defects are removed to produce clear, defect-free parts. Currently, human operators identify and locate the unusable board areas containing defects. Errors in determining a defect and its location, known as operator error, lead to lower lumber yield and increased product cost. Technology exists that would alleviate these problems and is a viable option to avoid wasting lumber because of human error. This study was performed in a rough mill collecting data on the errors made by humans when marking defects. Computer-based simulation tools were used to assess the significance of these errors. It was found that three-quarters of the decisions made by human operators are erroneous in some way resulting in an absolute yield loss of approximately 16.1%. Thus, automated defect detection systems that perform more accurately than do humans could have a payback period of 1 year or less.
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TL;DR: In this article, a new system for increasing CNC machining productivity is described, which is based on registering the moment when the cutting tool touches the workpiece during a machining operation.
Abstract: In this paper a new system for increasing CNC machining productivity is described. The system is based on registering the moment when the cutting tool touches the workpiece during a machining operation. The cutting tool approaches the workpiece with rapid traverse and switches to work feed when it comes in contact with it. In this way, the time for ‘cutting air’ can significantly be reduced.
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TL;DR: This work develops an OBEM-compliant object-based equipment (OBE) in the framework environment, so that this equipment can directly communicate with the MES by method invocation without using the SECS/GEM protocol.
Abstract: Traditionally, all the conventional semiconductor equipment must comply with the semiconductor equipment and materials international (SEMI) semiconductor equipment communication standard/generic equipment model (SECS/GEM) standards to interface with the cell controllers of a legacy manufacturing execution system (MES). In 1998, SEMATECH developed the computer integrated manufacturing (CIM) framework specification to facilitate the creation of an integrated, common, flexible, modular object model leading to an open, multi-supplier CIM system environment in the semiconductor industry. Later, SEMI developed an object-based equipment model (OBEM) standard to take full advantage of the CIM framework. With OBEM, the equipment can communicate with the CIM framework directly by method invocation. This work develops an OBEM-compliant object-based equipment (OBE) in the framework environment, so that this equipment can directly communicate with the MES by method invocation without using the SECS/GEM protocol. The unified modeling language is adopted as the major tool for analyzing and developing the target system. A SECS/GEM adapter is also added on the OBE to enable the OBE to communicate with a legacy factory that uses SECS/GEM standards as the communication protocol. A die bonder is used as an example for development demonstrations.