Cost estimates to guide pre-selection of processes

Strojarstvo Casopis Za Teoriju I Praksu U Strojarstvu, 2010

2009

The field of our research is defining the main criteria for selection of primary processes and types of operations in production. Selection of primary process is based on nature of material, quantity, form complexity of the part, part size/mass and some other factors. Type and sequence operation are results of influence different factors as product shape, surface roughness and tolerance. In application will be used some aspects of knowledge base. Application will enable users to better understand procedure of selection primary process and sequence operations with possible additional technological gradation support. Self learning and testing of students is included in application. In application are used IT technologies of Visual Basic.NET. .

2003

Integrated Design and Manufacturing in Mechanical Engineering ’98, 1999

Manufacturing process selection involves two steps. The first involves the screening of all available processes to determine whether they are technically capable of making the design; the second involves the ranking of those which are successful, using economic criteria. The ranking step requires techniques of cost-estimation. In seeking to achieve this, two problems are encountered. The first: that the design is still in an early stage at which little information is available; the second: that conventional cost-estimation techniques require detailed information and cannot easily be applied to widely diverse processes. A simple approach for this problem is presented. It is based on the idea of a resource-consumption cost model, applicable early in the design process. The system is described and a case study is used to demonstrate how it works. RESUME La sélection d'un procédé de fabrication comprend deux étapes. La première consiste a évaluer les différents procédés afin de vérifier qu'ils permettent, d'un point de vue technique, d'obtenir un produit en accord avec les spécifications. La seconde étape consiste a classer les procédés retenus selon des critères économiques. Cette phase fait intervenir des techniques simples d'estimation de coût. Cependant, on rencontre au cours de cette sélection deux types de problèmes. Le premier d'entre eux est lié au fait qu'elle intervient alors que la conception du produit est peu avancée, ce qui limite la quantité d'informations disponibles. D'autre part, les techniques précises d'estimation de coût, qui existent pour certains procédés de fabrication, nécessitent des renseignements détaillés concernant le procédé. L'objet de la presentation est d'aborder ce probleme par une approche simple, basée sur l'idée d'un modèle d'évaluation des coûts liés à la consommation des ressources, et applicable au début de la démarche de conception. Le système sera décrit et une étude de cas sera utilisée afin de montrer comment il fonctionne. * The current selector divides materials into 9 classes and shapes into 24 categories. Processes are also divided into classes: primary, secondary, and tertiary; with subclasses under each [ESA.97].

2008

The field of our research is defining the main criteria for selection of primary processes and types of operations in production. Selection of primary process is based on nature of material, quantity, form complexity of the part, part size/mass and some other factors. Type and sequence operation are results of influence different factors as product shape, surface roughness and tolerance. In application will be used some aspects of knowledge base. Application will enable users to better understand procedure of selection primary process and sequence operations with possible additional technological gradation support. Self learning and testing of students is included in application. In application are used IT technologies of Visual Basic.NET.

Instructional objectives By the end of this lecture, the student will learn what are the different types of manufacturing processes and manufacturability of engineering materials. Manufacturing Processes and Classification Manufacturing processes are the steps through which raw materials are transformed into a product. The manufacturing processes can be broadly classified into three categories viz. shaping, joining and finishing processes as shown schematically in Fig 1. The selection of a particular process from a wide range of choices for a given application requires a hierarchical classification of the processes. For example, Fig 2 depicts how the shaping family can be expanded in different classes such as casting, deformation, moulding, composite and powder processing, and prototyping. Next, moulding as a class can be enlarged into a number of member processes such as compression, rotational, transfer, injection moulding, etc. Lastly, each member process can be identified with a number of attributes, which would facilitate the selection of a member process for a given material, dimension, level of requisite tolerances and so on. Similarly, Fig 3 depicts how the joining and machining family can be expanded in different classes and actual processes. A brief description of the three broad categories of the manufacturing processes and the corresponding classifications are outlined in the following: [1] and [2].

Catalysis Today, 1997