Manufacturing Methods -...

Manufacturing Methods

Technology II – Jan Tomíček

Machining operations

• Machined parts

– Rotational – cylindrical (shafts) or disk-like

– Nonrotational(Prismatic) – block-like or plate-like

• Elementary shapes

– Rotational,

– planes,

– contoured.

Examples

Machining operations:

creating a shape

• generating – by the feed trajectory of the tool

• forming – by the geometry of the tool

• combination – of both processes

Machining – generating

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Machining – forming

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Machining – combination of forming

and generating

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Material removal processes

Conventional machining

Turning and related ops.

Drilling and related ops.

Milling and related ops.

Broaching, Shaping,

Other machining ops.

Abrassiveprocesses

Grinding

Other abrasive processes

Non-traditional machining

Mechanical energy processes

Electrochemical machining

Thermal energy processes

Chemical machining

Material forming processes

Classification of manufacturing methods

• Material removal processes

A CUTTING TOOL

• single-point tool (a)

• multiple cutting edge tool (b)

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CUTTING EDGE• face - rake angle RA α

• flank - relief angle ERA γ

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Manufacturing Methods

Turning, Milling, Drilling

Turning

Main movement – rotational – workpiece

Feed movement – linear – tool

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Lathe operations

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Turning tools - examples

Turning machine - lathe

• Very long history (Egypt, Greece)

• 1300 BC

• Manually powered

• Water, steam

• Transmisions, gearbox

• Electric power, electronic control

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A lathe – workholding methods

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PART QUALITY CHARACTERISTICS

The quality of functional surfaces of a part –

4 main parameters (in a part drawing):

• dimension accuracy (a tolerance) –

a grade of fit (marked IT)

• shape accuracy

• relative location parameters

• surface roughness Ra

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Turning – work time x IT relation

0

50

100

150

200

250

300

350

400

IT 7 IT 8 IT 9 IT 10 IT 11 IT 12

400

280

180

10090

65

%

Work time

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Turning – work time x Ra relation

0

20

40

60

80

100

120

140

160

180

1.6 3.2 6.3 12.5

170

135

120

100%

Ra

Work time

Work time

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Turning – tolerances and surface finish

Type of cut IT Ra

roughing 11 - 14 12,5 - 100

finishing 9 - 11 1,6 - 12,5

NC machines finishing 6 – 9 1,6 - 6,3

fine finishing (sintered

carbide)6 – 8 0,4 - 1,6

fine finishing (diamond) 5 – 6 0,2 - 0,8

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DRILLING

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Operations related to drilling

Drilling and whatnext?

• Drill(twist)

• Reamer drill – 3-4 twisted flutes and edges

• Reamer – 4-18 linear edges

• Dimensions?

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Twist drill Reamer drill Reamer

28,5 29,75 30H7

Drilling machine – drill

• Hand drill

• Table drill

• Stand drill

• Radial drill

+CNC machines

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Drilling – tolerances and surface finish

Process/tool IT Ra

drilling (twist drill) 11 – 13 3,2 –

12,5

rough reaming

(reamer drill)9 – 10 1,6 – 6,3

reaming (reamer) 6 – 8 0,4 – 1,6

counterboring 7 – 10 1,6 – 6,3

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MILLING• plain (peripheral) milling – the axis of the tool is

parallel to the surface being machined

• face milling – the axis of the cutter is perpendicular to the surface being milled

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Face milling - examples

►facing ► end milling(a milling head) (an end mill)

End milling

• Variation of tool shapes

• Generative process

Milling machine

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Milling – tolerances and surface finish

Type of cut IT Ra

roughing 10 – 13 6,3 – 25

finishing 8 – 10 1,6 – 6,3

fine finishing 7 – 8 0,8 – 1,6

Manufacturing Methods

BROACHING

BROACHING• a multiple tooth cutting tool• the forming tool moves linearly relative to the

workpiece in the direction of the tool axis• Movement through or along the part

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Broaching tool

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External broaching tool

Broaching process

• on a press – the tool is pushed

• on a broaching machine – the tool is pulled

• Using special machine – stationary broach

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Broaching machines• vertical ►

• horizontal ▼

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Broached shapes

• Internal – holes and other round shapes, keyways, profiles, gears

– Need leading hole to place the pilot

• External – faces, T-shape, co-planar surfaces, gears

• Holes calibration – Broach diameter slightly bigger than the hole.

Keyway broaches

Rotary broaching

• internal

Rotary broaching - limitations

Broach lengthSpiraling

Broaching limitions

• Machined volume

– Limited by chip thickness long broach

• Speed

– No wear demands low temperature, forces

• Tool costs

– Expensive production long tool life

Broaching – tolerances and surface finish

Type of cut IT Ra

surface roughing 7 – 9 0,8 – 3,2

surface finishing 5 – 7 0,1 – 0,8

hole roughing 7 – 8 0,8 – 3,2

hole finishing 5 – 7 0,1 – 0,8

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Video links

• Turninghttps://youtu.be/8EsAxOnzEms

• Millinghttp://www.youtube.com/watch?v=U99asuDT97Ihttp://www.youtube.com/watch?v=RIbdYmmhPDIhttp://www.youtube.com/watch?v=hMK7g_PpCv8http://www.youtube.com/watch?v=J1VtofzVG24http://www.youtube.com/watch?v=r7-eEj_qq5Mhttp://www.youtube.com/watch?v=IPWGV_EGAHwhttp://www.youtube.com/watch?v=9OsNUi_o6C4http://www.youtube.com/watch?v=HfIaISnqHOkhttp://www.youtube.com/watch?v=om6GQKfoS1g

Video links

• Broaching

http://www.youtube.com/watch?v=e26kCaPjX8E

http://www.youtube.com/watch?v=0Qe4ZGlhnhQ

http://www.youtube.com/watch?v=-ksHvyeIb-U

• Rotary

http://www.youtube.com/watch?v=BhvNU2E_x_Y

• Making a broach

http://www.youtube.com/watch?v=WE9ZfnP2SX8