Manufacturing Process Property enhancing, Monografías, Ensayos de Tecnologías de Producción

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Manufacturing Processes

Chapter 1:

Introduction

Dr. Yazan Al-Zain Department of Industrial Engineering University of Jordan, Amman-Jordan

What is Manufacturing??

• The word manufacturing is centuries old and

derived from two Latin words manus (hand) and

factus (make); the combination means by hand.

Hence manufacturing literally means made by

hand.

• Although modern manufacturing is accomplished

by automated and computer-controlled

machinery the word manufacturing is still in use.

Figure 1.1 (b) Manufacturing as an economic process Figure 1.1 (a) Manufacturing as a technical process

Manufacturing Defined

Manufacturing Industries and

Products

• (^) Manufacturing is important to our lives. Yet, we do not manufacture stuff just for the sake of manufacturing. We manufacture because we want to make money!
• (^) Industries in manufacturing is divided into three major categories; Primary, Secondary and Tertiary Industries.

1. Primary industries are those that cultivate and exploit natural resources, such as agriculture and mining.
2. Secondary industries are those that take the outputs of the primary industries and convert them into consumer and capital goods. (This type is of our concern because it is engaged directly in manufacturing).
3. Tertiary industries constitute the service sector of the economy..

Manufacturing Industries and

Products

• (^) Production Quantity ( Q ) and Product Variety ( V ).

1. The quantity of products made by a factory has a great influence on the way its people, facilities and procedures are organized. Annual production can be classified into 3 ranges:

• (^) Low production: quantities in the range 1 to 100 units/year.
• (^) Medium production: from 100 to 10,000 units/year.
• (^) High production: 10,000 to millions of units/year. However and depending on the kinds of products, these ranges may shift by an order of magnitude or so.

2. The product variety: since some factories specialize in high production of only one product type while other factories produce a variety of products each type being made in low or medium quantities, it is instructive to identify product variety as a parameter distinct from production quality. It is logical to consider factories with a high number of product types to have high product variety.

Manufacturing Industries and

Products

• (^) There is an inverse correlation between production quantity and product variety. The higher the production quantity the lower the product variety and vise versa.
• (^) Manufacturing plants tend to specialize in a combination of Q and V that lies somewhere inside the diagonal band in the figure. Figure 1.2 Relationship between Q and V.

Manufacturing Capability

• (^) A manufacturing plant consists of processes and systems (and people, of course) designed to transform a certain limited range of materials into products of increased value.
• (^) Modern manufacturing consists of three main blocks; materials, processes, and systems.
• (^) Manufacturing capability can be defined as the technical and physical limitations of a manufacturing firm and each of its plants.
• (^) Dimensions of capability are: Technological Processing Capability, Physical Product Limitations and Production Capacity.

• (^) Technological Processing Capability (TPC): a plant’s TPC is its available set of manufacturing processes. The type of manufacturing processes defines the type of the plant, e.g. A machine shop can build cars while a rolling mill can roll steel but not the other way around!
• (^) Certain manufacturing processes are suited to certain materials, while other processes are suited to other materials.
• (^) TPC includes not only the physical processes but also the expertise possessed by the plant personnel in these processing technologies.
• (^) Companies must concentrate on the design and manufacture of products that are compatible with their TPC.

Manufacturing Capability

• (^) Production Capacity (PC): A third limitation on plant’s

manufacturing capability is the production quantity that

can be produced in a given time period. This quantity

limitation is commonly called Plant Capacity, or

Production Capacity.

• (^) PC is the maximum rate of production that the plant can

achieve under assumed operating conditions (no. of

shifts per week, hours per shift, etc).

• (^) PC is measured in terms of output units, such as annual

tons of steel produced by a steel mill.

Manufacturing Capability

Materials in Manufacturing

• (^) Most engineering materials can be classified into one

of the three basic categories: (1) Metals, (2) Ceramics

and (3) Polymers.

• (^) They have different chemistries and their mechanical

and physical properties are dissimilar.

• (^) These differences affect the manufacturing processes

that can be used to produce products from them.

• (^) In addition, there are (4) Composites:

nonhomogenious mixtures of the other three basic

types rather than a unique category.

Materials in Manufacturing

[1] Metals: metals used in manufacturing are usually in the form of

alloys (two ore more elements, at least one of which is metallic). Metals are divided into two basic groups; ferrous and nonferrous. a. Ferrous metals: based on Iron (Fe) as the major alloying element. This group includes steel and cast iron.

• (^) More than 75% of the metal tonnage throughout the world.
• (^) Fe has limited commercial use, but when alloyed with carbon (C), Fe has more use and greater commercial value than any other metal.
• (^) Fe when alloyed with C forms Steel or Cast Iron.

Materials in Manufacturing

• (^) Steel : Is an Iron-Carbon alloy containing 0.02 to 2.11 wt.

% C.

• (^) Most important category within the ferrous metals group,

due to low cost and good mechanical and physical

properties.

• (^) Its composition contains other metals such as Mg, Cr, Ni,

Mo, etc, to enhance the properties of the alloy.

• Used widely in construction, transportation and consumer

products.

Materials in Manufacturing

b. Nonferrous metals: These include other metallic elements and their alloys.

• In almost all cases, the alloys are more important commercially than the pure metals.
• (^) Some examples are Gold alloys, Titanium alloys, Copper alloys, etc.

Materials in Manufacturing

[2] Ceramics: A compound containing metallic (or semimetallic) and

nonmetallic (O, N and C) elements.

• (^) Traditional ceramics: Been used for thousands of years. They include: clay (consists of fine particles of hydrous aluminum silicate and other minerals used in making brick, tile and pottery); silica (the basis of nearly all glass products); and alumina and silicon carbide (abrasive materials used in grinding).
• (^) Modern ceramics: Consists of alumina of enhanced properties. Newer ceramics include carbides, metal carbides such as tungsten and titanium carbides (used as cutting tool materials); and nitrides (e.g. titanium nitride and boron nitride, used as cutting tools and grinding abrasives).
• (^) For processing purposes, ceramics can be divided into (1) crystalline ceramics and (2) amorphous ceramics (glasses). The former are formed in various ways from powders and then sintered, while the later can be melted and cast and then formed (e.g. glass blowing).