Manufacturing Methods Technology II – Jan Tomíček

Machining operations Machined parts Elementary shapes Rotational – cylindrical (shafts) or disk-like Nonrotational(Prismatic) – block-like or plate-like Elementary shapes Rotational, planes, contoured. Rotational – cylinder (válec) cone (kužel) eliptical surface (eliptický povrch) Planes – pyramid (jehlan) cube (krychle) block (kvádr) Contoured – different shapes (různé tvary)

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

Machining – forming

Machining – combination of forming and generating

Classification of manufacturing methods Material removal processes Conventional machining Turning and related ops. Drilling and related ops. Milling and related ops. Broaching, Shaping, Other machining ops. Abrassive processes 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)

CUTTING EDGE face - rake angle RA α flank - relief angle ERA γ

Manufacturing Methods Turning, Milling, Drilling Only very brief description – should be allready known from the course „Fundamentals of technology“ or from other course as required assumption to enter the course TE2

Turning Main movement – rotational – workpiece Feed movement – linear – tool Versatile technology

Lathe operations

Turning tools - examples

Turning machine - lathe Very long history (Egypt, Greece) 1300 BC Manually powered Water, steam Transmisions, gearbox Electric power, electronic control

A lathe – workholding methods

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

Turning – work time x IT relation

Turning – work time x Ra relation

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

DRILLING

Operations related to drilling

Drilling machine – drill Hand drill Table drill Stand drill Radial drill

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

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

Face milling - examples ►facing ► end milling (a milling head) (an end mill)

End milling Variation of tool shapes Generative process

Milling machine

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

Broaching tool

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

Broaching machines vertical ► horizontal ▼

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 length Spiraling

Broaching limitions Machined volume Speed Tool costs 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 hole finishing

Video links Turning https://youtu.be/8EsAxOnzEms Milling http://www.youtube.com/watch?v=U99asuDT97I http://www.youtube.com/watch?v=RIbdYmmhPDI http://www.youtube.com/watch?v=hMK7g_PpCv8 http://www.youtube.com/watch?v=J1VtofzVG24 http://www.youtube.com/watch?v=r7-eEj_qq5M http://www.youtube.com/watch?v=IPWGV_EGAHw http://www.youtube.com/watch?v=9OsNUi_o6C4 http://www.youtube.com/watch?v=HfIaISnqHOk http://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