Corso di Studi di Fabbricazione - Unibg - Introduction...3 Università di Bergamo –DIGIP...

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Università di Bergamo – DIGIPTecnologie e Sistemi di Lavorazione

Studi di Fabbricazione – 2018 - 1

Corso diStudi di Fabbricazione

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Introduction to manufacturing

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MANUFACTURING - TECHNOLOGICALLY IMPORTANT

• Technology provides the products that help our society and its members to live better

• What do these products have in common?

• They are all manufactured

• Manufacturing is the essential factor that makes technology possible

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MANUFACTURING - ECONOMICALLY IMPORTANT

• Manufacturing creates nation material wealth

• GNP = gross national product

U.S. economy:

Sector% of

GNP

Manufacturing 20%

Agriculture, minerals, etc. 5%

Construction & utilities 5%

Service sector – retail,

transportation, banking,

communication, education, and

government

70%

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MANUFACTURING - HISTORICALLY IMPORTANT

To a significant degree, the history of civilization is the history of humans' ability to make things

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WHAT IS MANUFACTURING?

• Manufacture derives from two Latin words manus (hand) and factus (make); “made by hand”

•“Made by hand” fabrication methods used when the English word “manufacture” was first coined around 1567 A.D.

•Most modern manufacturing operations are mechanized and automated (supervising of human workers)

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MANUFACTURING – TECHNOLOGICAL DEFINITION

• Application of physical and chemical processes to alter the geometry, properties and/or appearance of a starting material to make parts or products

• Manufacturing also includes assembly

• Almost always carried out as a sequence of operations

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EXAMPLE

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OPERATION: BLANKING (CUTTING)

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OPERATION: DRAWING

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OPERATION: DEEP DRAWING

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OPERATION: FORGING, HEAT TREATING, CUTTING

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OPERATION: TIG WELDING, FASTENING

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OPERATION: HIGHLY POLISHING

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PRODUCTION PROCESSES- OVERVIEW

• MECHANICAL TECHNOLOGY or MECHANICAL PRODUCTION TECHNOLOGY, deals with all processes able to transform raw materials (or semi-finished products) into end products.

• The PRODUCTION ENGINEER, by designing the cycle of transformation from raw materials into end products, allows a design to be physically made.

• Behind each product there is a TECHNOLOGICAL CYCLE, completely detailed, so that each production step can be performed correctly.

• In general, the main guiding issue for cycle selection is ECONOMICAL. Among several possible production routes, the cheapest way is preferred.

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Wood

Turning and decoration

Metallic spiral

Cold plastic deformation and painting

Example: EGG CUP

Simple product:

• Mono-function

• Mono-material

• Mono-technology

FROM FUNCTIONS TO THE PRODUCT

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Metallic (steel sheet)

Deep drawing of stainless steel

Metallic (aluminum sheet)

Deep drawing and bending of aluminum


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Polymer

Polymeric material injected in moulds


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Porcelain

Cold forming, heat treatment and decoration

Glass

Heating of the material and forming

The connection between material, shape, manufacturingtechnology and costs of each product must be taken intoaccount


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TYPES OF PRODUCTION

• We can divide production into two main groups:• FLOW production (or continuous p.)

• BATCH production (or discrete p., sometimes the word “manufacturing” is used for this case only)

• Each good is produced using one (sometimes either) of these types.

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FLOW PRODUCTION

• At the end of the process, it is very difficult to recognize the raw materials. No disassembly is feasible.

• In general flow production involves either:• Mixing, Solving

• Chemical reactions

• Typical FLOW productions involve:• Steel

• Paper

• Cement (for Concrete)

• Chemicals

• Yarn

• ...

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BATCH PRODUCTION (Manufacturing)

• Batch product is made of individual parts, assembled together, that can be easily distinguished (very often in different materials).

• In general batch production involves two main phases:• Part production

• Assembly

• Therefore, we use batch production for:• Cars

• Computers

• Household Appliances (washing machines, refrigerators)

• ...

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PART PRODUCTION PHASE

• Part Production: • sequence of OPERATIONS (TRANSFORMATIONS) to change shape,

dimensions, surface finish or other properties of simple (elementary) parts

gearsframe

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ASSEMBLY PHASE

• Assembly:• Sequence of ACTIONS for grouping, positioning and fixing parts into

an assembly

N.B.: it’s a hierarchicalsequence, i.e. simpleparts are firstassembled into sub-assemblies, then sub-assemblies are groupedinto finished product.

….. …..

Sub-assembly

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PRODUCTION QUANTITY Q

• The quantity of products Q made by a factory influences the way it works, and so the procedures are organized

• Annual production quantities can be classified into three ranges:

Production range Annual Quantity Q

Low production 1 to 100 units

Medium production 100 to 10,000 units

High production 10,000 to millions of

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PRODUCT VARIETY P

• Product variety P refers to different product types or models produced in the plant

• Different products have different features • They have different geometry, properties, appearance

• They are intended for different markets

• Some have more parts than others

• Number of different product types made each year

• When the number of product types made in the factory is high, this indicates high product variety

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P VERSUS Q IN FACTORY OPERATIONS

• Figure 1.2 P-Q Relationship

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Prodotti

Vo

lum

i d

i p

rod

uz

ion

e

LINEE

CELLE

JOB-SHOP


Cell

Line

Job-shop

Products

Pro

duct

ion V

olu

me

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MATERIALS IN MANUFACTURING

• Three basic categories: • Metals

• Ceramics

• Polymers

• Their chemistries are different

• Their mechanical and physical properties are dissimilar

• These differences affect the manufacturing processes that can be used to produce products from them

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IN ADDITION: COMPOSITES

• Nonhomogeneous mixtures of the other three basic types rather than a unique category

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Raw, semifinished

MANUFACTURE

Component

Assembly

ASSEMBLY

FINISHING , TEST, …

Finish product

MANUFACTURING PROCESSES

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PROCESSING OPERATIONS

• Alters a material’s shape, physical properties, or appearance in order to add value

• Three categories of processing operations: • Shaping operations - alter the geometry of the starting work

material

• Property-enhancing operations - improve physical properties without changing shape

• Surface processing operations - to clean, treat, coat, or deposit material on exterior surface of the work

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SHAPING PROCESSES – MAIN CATEGORIES

1. Solidification processes - starting material is a heated liquid or semifluid

2. Particulate processing - starting material consists of powders

3. Deformation processes - starting material is a ductile solid (commonly metal)

4. Material removal processes - starting material is a ductile or brittle solid

5. Other processes - (nonconventional) EDM, Laser, AWJ…

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WASTE IN SHAPING PROCESSES

• Desirable to minimize waste in part shaping

• Material removal processes are wasteful in unit operations,

• Most casting, molding, and particulate processing operations waste little material

• Terminology for minimum waste processes:• Net shape processes - when most of the starting material is used

and no subsequent machining is required

• Near net shape processes - when minimum amount of machining is required

Waste is different from Scrap(due to defective products)

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PROPERTY-ENHANCING PROCESSES

• Performed to improve mechanical or physical properties of work material

• Examples: • Heat treatment of metals and glasses

• Sintering of powdered metals and ceramics

• Part shape is not altered, except unintentionally• Example: unintentional warping of a heat treated part

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SURFACE PROCESSING OPERATIONS

• Cleaning - chemical and mechanical processes to remove dirt, oil, and other contaminants from the surface

• Surface treatments - mechanical working such as sand blasting, and physical processes like diffusion

• Coating and thin film deposition - coating exterior surface of the workpart

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ASSEMBLY OPERATIONS

• Two or more separate parts are joined to form a new entity

• Types of assembly operations:• Joining processes – create a permanent joint

Welding, brazing, soldering, and adhesive bonding

• Mechanical assembly – fastening by mechanical methods

Threaded fasteners (screws, bolts and nuts); press fitting, expansion fits

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SOLIDIFICATION PROCESSES

• Starting material is heated sufficiently to transform it into a liquid or highly plastic state

• Examples: metal casting, plastic molding

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Sand castingExpanded polystyrene

casting Shell Molding

Die Casting Investiment and microcasting

SOLIDIFICATION PROCESSES

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PARTICULATE PROCESSING

• Starting materials are powders of metals or ceramics

•Usually involves pressing and sintering, in which powders are first compressed and then heated to bond the individual particles

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DEFORMATION PROCESSES

• Starting workpart is shaped by application of forces that exceed the yield strength of the material

• Examples: (a) forging, (b) extrusion

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Hot Rolling Cold RollingShape Rolling

Mannesmann roll mill for producing seamless tubing


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Roll bending

BendingDrawing


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MATERIAL REMOVAL PROCESSES

• Excess material removed from the starting piece so what remains is the desired geometry

• Examples: machining such as turning, drilling, and milling; also grinding and nontraditional processes

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Raw materials

Components

DESIGN

PRODUCTION

Product Specifications

Functions

Product


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PRODUCT

Idea and functions

Materials and components

characteristics

• Physical

• Resistence

• Cost

Technologies

• Manufacturing

• Joining

• Protection

• Cost

Global cost

• Starting cost

• Working cost

MAIN ELEMENTS

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Costs

Technologies

Materials

PRODUCT REALIZATION

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They represent the «connection» necessary to realize ‘ideas’ and ‘functions’ by means of materials

transformation

TECHNOLOGIES

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QUESTIONS ?

Corso di Studi di Fabbricazione - Unibg - Introduction...3 Università di Bergamo –DIGIP...

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