Machine Tool design MEng 5310

Chapter one

Introduction

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• . Introduction: • 1.1. Definition and objectives of machine tools design• 1.3. Design by evolution and innovation• 1.4. Essential factors to design • 1.5. Production –consumption cycle• 1.6 Tolerance & process capability in design and

assembly• 1.7 Design considerations, Industrial Design,

Aesthetics

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Definition and objectives of machine tools

• Machine tools are devices for cutting materials (mostly metals), to impart them the required shape.

• Machine tool is a mechanism for applying force and motion to a cutting instrument called a tool

• Objectives of machine tools are:i. To produce surface

ii. To trace formed curves

iii. To provide a finish to a given surface

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Qualifications of machine tool for further definition

• machine tool does not always apply force and motion to the tool, but sometimes applies them to the material to be cut,

• machine tool usually does not including such power tools as – cutoff saws, shears, punch presses, routers, and the like

• Because , they do not machine metals by “cutting chips”

• true machine tools also provide: – means for accurately controlling the tool to take as deep or

as shallow a cut – means for applying this action consecutively in the

direction needed to obtain the desired finished shape. – means for interrupting this action whenever necessary,

Dgmawi Hailu, MEng, ASTU

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The Design of Machine Tools• the machine tools aspect was very bound by:

– their structure and – function, – artistically and – intellectual conceptions of the epoch.

• The machine tools design is the result of the shape modeling in the report with functional role.

• In the machine design, – the shape like an essential characteristic – Aesthetic aspect – Functional requirements– Ergonomics

• machine tools design must respect the basic principles of the design: – the proportion, the rhythm, the symmetry and the contrast

are created for to respond to an aim in the using of the user

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The putting in proportion for a milling machine

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Design by evolution and innovation

• An evolutionary process is one that occurs without a conscious effort to direct it.

• the process of evolution is one to be accepted rather than controlled and could therefore be considered as a passive process

• Biologically, changes in behavior or survival techniques of one generation in their adaptation to the world about them are passed through to some extent to the succeeding generation.

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Design by evolution and innovation…

• If one were to plot a curve of change vs. time for, say, a biological evolution of a species, the curve would probably take the general shape of the curve of the following figure

Evolutionary curve

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Design by evolution and innovation cont…

• To start a new curve requires, as in biology, a quantum change.

• This quantum change then becomes the origin of a new curve, and in engineering technology, this quantum change is simply "innovation."

• The vast majority of engineering designs are evolutionary in that they evolve from the designs and concepts of preceding generations

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a "new" field of technology

As an industry matures, both design engineers and the business settle into a more comfortable pace.

inevitable obsolescence caused by lack of innovation.

Thus, in the field of design engineering, innovation is the key to success and should be the primary objective in every design undertaken.

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• Innovative design. on the other hand:– looks at the basic goal to be accomplished, – then considers how this goal might be best

accomplished• through implementation of the laws of physics and then-

current knowledge of prior successes and failures.

• It is only after a solution or solutions to this accomplishment have been developed that the present methods and available materials are considered.

Innovative design

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