Wyniki wyszukiwania - Biblioteka Nauki

1

Integration of part classification, cell formation and capacity adjustment

100%

Tolouei-Rad M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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tom Vol. 39, nr 2

197-203

EN

Purpose: Improving the productivity of a large manufacturing firm through development and implementation of a group technology model in a real manufacturing environment. This incorporates classification of parts, coding of parts and par families, formation of machine cells, and minimization of machine idle times through machine cell capacity adjustment. Design/methodology/approach: An algorithm has been developed for classification of all the parts into part families on the basis of manufacturing similarities. This formed 144 par families for more than 7500 different parts in production. The algorithm assigned group technology code to each part and a part family code to each part family. The former represents manufacturing characteristics of the part and the latter simplifies determination of part families. A number of machine cells were developed to produce all of the part families. After classification the system automatically directs each part to the appropriate machine cell for manufacturing. A computer software has been developed that automated the functions of classification of parts and assigning a group technology code to each part, determination of part families and assigning part family codes, and directing part families to appropriate machine cells for production. Findings: Introducing part family codes in addition to group technology codes considerably simplified the task of part family determination. Application of the system immediately resulted in an increased productivity of about 50%. This was due to the reduced setup times, less flow of parts in the workshop, production of similar parts due to parts classification, etc. Yet a productivity improvement of 100% or more is anticipated in near future. Research limitations/implications: As the manufacturing firm was producing a wide range of products at the time of implementation of this work, it was difficult to implement the project without affecting the production flow significantly. There has also been some resistance from technical people opposing a change in traditional production methods. Originality/value: Integration of machine cell formation with capacity adjustment is of great value that resulted in significant productivity improvements. Also some issues regarding actual implementation of group technology and associated problems and issues, coding of parts and part families, formation of machine cells, and capacity adjustment of machine cells have been dealt with and discussed in this paper.

2

A comparative approach to modelling of hard tissues

100%

Tolouei-Rad M.

Archives of Materials Science and Engineering

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2010

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tom Vol. 42, nr 2

119-125

EN

Purpose: Investigating the capabilities of commercial CAD/CAM systems in producing 3D models of body bones from 2D medical images and application of resulting models in rapid manufacturing of customized implants. Design/methodology/approach: Geometrical information of 2D medical images extracted via an image processing and filtering mechanism, and converted into 3D models by Commercial CAD software systems. After applying a median filter to improve the quality of 2D images, they are segmented and bone edges are detected with histogram threshold method. With the aid of an Auto LISP program, detected edges are transferred to AutoCAD as a series of points. Splines are drawn over the points and redundant points deleted. Then by transferring resulted splines into the modeler, 3D models are constructed. Different implant manufacturing methods have been studied and rapid manufacturing methods have been recognized to be suitable for customized implant fabrication. Findings: A number of CAD software packages proved to be capable of producing 3D models using generated information, however, human intervention is needed for all systems tested. Different systems tested exhibited strenthnesses and weaknesses. Research limitations/implications: Automatic generation of 3D models of body bones from 2D images is desirable. Also development of an intelligent system for manufacturing of customized implants is highly desirable. Originality/value: Method of extracting geometric data from medical images and presenting this data in a format suitable for commercial CAD systems for making 3D models is of high value. Also the performance comparison of various CAD systems is very important.

3

An intelligent approach to high quantity automated machining

100%

Tolouei-Rad M.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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tom Vol. 47, nr 2

195--204

EN

Purpose: To investigate the possibility of application of knowledge-based expert systems to facilitate the task of techno-economical feasibility analysis of utilization of special purpose machines for high quantity production tasks. Also, to study the possibility of assisting special purpose machine designers in applying knowledge-based expert systems in the design task in order to reduce required machine design time, improve machine design efficiency, and eliminate possible human errors. Design/methodology/approach: Development of a knowledge-based expert system has been proposed to help decide where to utilize special purpose machines to accomplish the production task. The knowledge-based expert system consists of a rule-base which contains qualitative human knowledge and expertise in the form of if-then rules; and a database which contains qualitative information of machining operations, and characteristics of standardized special purpose machine components. Findings: A case study has been presented where an analysis has been made on the basis of techno-economical considerations for a typical part with three machining operations to be produced in large quantities. It has been concluded that for the given production task, special purpose machines would result in a significant 59% reduction of costs compared to CNC machines, and 95.5% compared to traditional machines. The proposed methodology also reduces the time and effort needed for decision making on utilization of special purpose machines and determination of machine layout. In addition, it minimizes the level of expertise required to perform these functions and eliminates possible human errors. Research limitations/implications: The current system focuses on drilling and drilling-related operations which cover about 60% of all machining operations. More work is needed to cover other machining operations including milling. Also the KBES developed currently works on a standalone basis. Work is in progress to integrate it with a 3D CAD modelling system. Upon completion the information could be directly extracted from the CAD system, eliminating the need for manual data input by the user. Originality/value: In spite of a large number of publications on machine tool design in the literature, publications on special purpose machines are very limited. The method of techno-economical analysis presented here for utilization of special purpose machines in comparison with other production alternatives is of great value to manufacturing engineers and specialists. Also the methodology presented for machine design and implementation is highly valued by machine tool designers and manufacturers.

4

An approach towards fully integration of CAD and CAM technologies

100%

Tolouei-Rad M.

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2006

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tom Vol. 18, nr 1-2

31--36

EN

Purpose: An integrated CAD/CAM system for milling operations has been developed which helps designers to solve machining problems at the design stage. Design/methodology/approach: A methodology has been employed which provides all necessary information for machining products automatically. Use of these system results in reduced machining leadtimes and cost through designing machinable components; using available cutting tools; improving machining efficiency. The system is menu driven with a user friendly interface. Findings: Different components for developing such a system have been identified and various problems that arose in the development of this system have been dealt with The system developed leads to an adequate basis for fully integration of CAD and CAM technologies in one system. It allows simultaneous generation of all information required to satisfy machining requirements of the design such as its machinability and availability of the required tooling resources. Research limitations/implications: Different components required for developing such systems have been identified and various problems that arose in the development of these systems have been dealt with, leading to an adequate basis for complete integration of CAD and CAM technologies. Although much of the work described here goes beyond the scope of published literature, however, it should be noted that the system developed couldn’t be considered as a complete solution to the CAD/CAM integration problem. Further work requires including other manufacturing activities that are considered in concurrent engineering concept. In this direction, further integration of the system developed with systems such as MRP, MRP II and assembly sequence planning packages are highly desirable. Originality/value: CAD/CAM integration is regarded as a solution for bridging the gap between design and manufacturing, one of the ultimate goals for concurrent engineering. Since the advent of CAD and CAM numerous attempts have been made to integrate these technologies; however, a full CAD/CAM integration is not yet achieved. In addition, most of the systems developed focus only on turning, leaving room for further investigation on other machining operations including milling. This paper goes one step closer towards achieving a full CAD/CAM integration for milling operations.

5

A hybrid approach to automatic generation of NC programs

63%

Tolouei-Rad M. , Payeganeh G.

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2006

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tom Vol. 14, nr 1-2

83--89

EN

Purpose: This paper describes AGNCP, an intelligent system for integrating commercial CAD and CAM systems for 2.5D milling operations at a low cost. Design/methodology/approach: It deals with different machining problems with the aid of two expert systems. It recognizes machining features, determines required machining process plans, cutting tools and parameters necessary for generation of NC programs. Findings: The system deals with different machining problems with the aid of two expert systems. The first communicates with CAD system for recognizing machining features. It is developed in LISP as machining features can be properly represented by LISP codes is ideal for manipulating lists and input data. The second expert system requires extensive communications with several databases for retrieving tooling and machining information and VP-Expert shell was found to be the most suitable package to perform this task. Research limitations/implications: 2.5D milling covers a wide range of operations. However, work is in progress cover 3D milling operations. The system can also be modified to be used for other activities such as turning, flame cutting, electro discharge machining (EDM), punching, etc. Practical implications: Use of AGNCP resulted in improved efficiency, noticeable time savings, and elimination of the need for expert process planners. Originality/value: The paper describes a method for eliminating the need for extensive user intervention for CAD/CAM integration.

6

Enhancing the reconfigurability of special purpose machine tools using mechanical module interfaces

51%

Farhan U. H. , Tolouei-Rad M. , Osseiran A.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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tom Vol. 85, nr 2

56--66

EN

Purpose: The purpose of this paper is to introduce a solution that can enhance the reconfigurability of special purpose machines (SPMs). This is because SPMs can be used in different configurations and the reconfiguring time for these machines can be crucial. Therefore, it is important to reduce this time in order to enhance the performance of SPMs. Design/methodology/approach: A mechanical adapter is proposed as a solution to achieve the purpose of this paper. The design of the adapter is based on Multi Coupling (MC) type, and its functionality is based on “Plug and Produce”. This adapter is used to modify an SPM element called workpiece transfer in order to accommodate two types of chucks without the need to change the workpiece transfer. The performance criteria are analysed and investigated for this adapter. Findings: The proposed solution will enhance the reconfigurability of SPMs. This is because it will reduce the number of elements that are needed for reconfiguration. As a result, the time and cost for the reconfiguration will be reduced considerably. Research limitations/implications: Because SPMs have several types of elements, adapting the proposed solutions to be used for all elements can be a complex process. Therefore, more investigation and analysis need to be carried out in order to build a complete adapter system for SPMs. Practical implications: SPMs are already used widely in manufacturing. However, they are considered relatively expensive compared to the traditional machines tools because they are applied for special applications. The proposed solution will help to overcome this problem and make SPMs applicable for wider applications. Originality/value: The proposed solution is the first attempt in terms of enhancing the performance of SPMs. This can bring considerable benefits to the end users in manufacturing, who are using SPMs, in order to reduce the reconfiguration time and cost for these machine tools.