Technology II

Manufacturing technologyIntroduction

Technology II –

Ing. Jan Tomíček Ph.D.Room no. B1-114

Jan.tomicek@fs.cvut.cz

Manufacturing

• Important part of World economy. Allmost all products are manufactured.

• Demands are increasing

• New issues – energy efficiency, waste, etical issues

Changes in the world of goods manufacturing

1. World wide competetion

2. New materials

3. Advanced technologies

4. New manufacturing systems

5. Enviromental issues

1. World Wide Competetion

• Global business

• Market = Whole world

• Everybody can make business –

– knowledge vs. capital

– customization vs. mass production

– Product placement vs. variability

2. New materials

• Demands from customers– Smooth surface on plastic parts

– Transparency of plastic

– Shiny metal look etc.

• New developed materials with betterproperties– Heat resistant materials

– High strength materials

– Special materials

3. Advanced technologies

• Complex products

• Combined principles

– Mechanical principles

– Electrical

– Electronical

– Combination

• Water, steam, electricity,

4. New manufacturing systems

• Manufacturing system

• Manufacturing strategies

• Management

5. Enviromental issue

• Low energy and material consumption

• Utilization of human labor, heavy work

• Health and security issues

• Ethical problems

Product Life Cycle

Design

Construction

Manufacturing

Sale

Service andrecycling

START-UP RAPID GROWTH MATURATION COMODITY or DECLINE

Product variety Great variety, productinnovation

Increasingstandartization

Emergence of a dominant stadart design

High standardization„comodity“ characteristics

Industry structure Small competetiors Fallout andConsolidation

Few large companies „Survivors“ becomecomodities

Form of competetion Product characteristics Product Quality, Costand availability

Price and Quality andReliability

Price with consistentquality

CostPer unit

Annual sales per model

SATURATION

TIME

Price of the product?

• What is the best price of the product?

Smallest, affordable, highest, psychologicallyfriendly, discounted??

Production costs!

Manufacturing costs

• Methods:

– Casting, foundry, moulding

– Forming of metalforming

– Machining(material removal)

– Surface treatments(finishing)

– Heat treatment

– Joining and assembling

• Machining is approx. 40% of manufacturing costs

TECHNOLOGY II

TECHNOLOGY I

Machining

• Chip removal process – Material is removed in form of chips from a piece of raw material to archive the desired shape.

• Material(chips) are removed by a tool from the blank

• This process is called „Chip forming“

What you allready should know…

• Course Technology II presumes knowledge ofbasic technologies of machining

• Prerequisite is course „Fundamentals ofTechnology“.

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ADVANTAGES• variety of work materials

• variety of part shapes and geometric features

• dimensional accuracy

• good surface finishes

DISADVANTAGES wasteful of material

time consuming

Material Waste?

Material utilization

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MACHINING (conventional)a sharp cutting tool is used to cut away

material to achieve the desired part

shape and quality

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A CUTTING TOOL

• single-point tool (a)

• multiple cutting edge tool (b)

Chip forming principle

• Continuous vs. discontinuous chip

Forcestresswork hardeningsaturation(fullyhardened material)shearconinuous chip

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CHIP FORMATION (orthogonal cutting schema)

• the tool is forced into the material

• plastic deformation → hardening of the material

• shear deformation – shear plane (angle φ)

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CHIP FORMATION

Secondary deformation zone

Chip breakers

• Preventing the built-up edge

– Groove type - premanufactured

– Obstruction type

Chip and Tool geometry

• Tool – rake & face angle

Chip thickness

• Chip thickness ratio𝛬ℎ =

𝑡𝑐𝑡𝑜=𝑡𝑐𝑎𝑝

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CUTTING CONDITIONS• cutting speed vc [m.s-1]; [m.min-1]• feed f [mm.rev-1]; [m.min-1]• depth of cut d = ap [mm]

Chip types

Chip breaking diagramme

Chip breaking diagramme

Chip volume ratio

• Calculation W =

• Value 3-400

• Large volume of chips

𝑊 =𝑉𝑐𝑉𝑜

Chips removal

• Chips must be removed

– From the cut – gravity, liquid, air etc.

– From the machine – liquid, automatic, manually

– From the workshop – conveyors, carriages

– From factory –

• recycling

What to think about?

• Next time

– resistance of material,

– cutting forces,

– heat and temperature