Shaping, planing and slotting operations

Shaping, planing and slotting operations

1. Ta 102
Workshop practice
Shaping, Planingand Slotting Operations
LecNo. 12-13
BY
Prof .A.Chandrashekhar

2. Introduction
Shaping,planningandslottingcanbedefinedasthe
processofremovingmetalfromasurfaceinhorizontal,
verticalandinclinedpositiontoproduceaflatorplane
surface,slotsandgroovesbymeansofarelative
reciprocatingmotionbetweenthetoolandworkpiece.

3. Thedifferencebetweenthethreeprocessesofshaping,
planingandslottingisthatinshapingandslotting,the
toolisreciprocatingandtheworkpieceisfedintothe
cuttingtoolwhileinplanning,theworkpieceis
reciprocatingandthetoolisfedin.

4. Thetoolreciprocateshorizontallyintheshapingand
verticallyinslotting.
Thecuttingisintermittentinallthethreeprocesses
becauseintherelativereciprocatingmotionthetoolcuts
onlyinforward-working(orcutting)strokefollowedby
theidle-returnstroke.

7. The Shaper
Themachinetoolusedforshapingoperationiscalledshaper.
Itisdesignedformachiningflatsurfacesonsmallsizedjobs.Ifthe
sizeofthejobislarge,thenplaningisused.
Inashaper,theworkpieceisheldstationaryduringcutting,while
thetoolreciprocateshorizontally.thefeedanddepthofcutare
normallyprovidedbymovingthework.Suchshaperiscalleda
horizontalshaper.

10. Types of Shaping Machines
Shapingmachinesarethereciprocatingtypeofmachine
toolsinwhichtheworkpieceisheldstationaryandthe
toolreciprocates.
Mostshapershavereciprocatingmotioninhorizontal
position(horizontalshapers)butshapersarealso
designedwithreciprocatingmotioninverticalposition(
verticalshapers)orslottingmachinesorslotters.

11. The Shaping Operation

12. The Shaper

14. Machining of Inclined Surface

15. Operating conditions in a Shaping Machine
CUTTING SPEED
It is defined as the average linear speed of the tool during the cutting
stroke in m/min, which depends on number of ram strokes( or ram cycles) per
minute and length of the stroke.

16. Stroke length = L
L
j= Job of length
C = Clearance
L= L
j+ 2XC

17. Feed
Feedfistherelativemotionoftheworkpieceinadirection
perpendiculartotheaxisofthereciprocationofthearm.
Inshaper,feedisnormallygiventotheworkpieceandcanbe
automaticormanual.
Itisexpressedinmm/doublestrokeorsimplymm/stroke
becausenocuttingisdoneinreturnstroke

18. Depth of Cut
Depth of cut d is the thickness of the material removed in
one cut, in mm.

19. Machining Time

20. Material removal rate

21. The Planer

22. Planner

23. The Planer
Theplanerorplaningmachineisamachinetool,which
liketheshaperproducesflatsurfacesinhorizontal,
verticalorinclinedplane.
Thefundamentaldifferenceisthattheplaneroperates
withanactionoppositetothatoftheshapers,i.e.,the
workpiecereciprocatespastoneormarestationary
singlepointcuttingtools.
Planersaremeantformachininglargesizedworkpieces,
whichcannotbemachinedbytheshapingmachines.

24. Types of PlaningMachines
Some other types of planingmachines include
Universal planer, pit type planer and edge
planer.

25. Operating Conditions in planers
Cuttingspeed
similartoshaper
Feed
thefeedinaplaningmachineisthedistancethetool
travelsatthebeginningofeachcuttingstrokeandis
expressedinmm/doublestroke
Depthofcut,MaterialRemovalrate.

26. Size of shaper and planers
The size of planer and shaper are specified by the maximum
length of stroke.
The normal maximum stroke length of the stroke is 800mm.

27. Slotting Machine

28. Slotting Machine

29. Problem 1

33. 18. Determine the machining time required to machine
three finished stocks of size 75mmX150mm X250mm
each from raw stocks of size 80mm X155mm X255mm.
Stock should be removed equally from all faces using the
following data:
Cutting sped =35m/min, maximum depth of cut: for
roughing= 2 mm and for finishing =1mm
Feed: for roughing = 0.5mm/stroke, and for finishing =
0.3mm/stroke
Cutting to return time ratio=3:1
total clearance= 50mm
Ans: 28.36 min

34. 19.The400mmX250mmfaceofcastironblockof
size400mmX250mmX100mmistoberough
machinedusingHSStoolonaconventionalcrank
shaper.Estimatethemachiningtimeassumingan
averagecuttingspeedof20m/minandafeedof
0.2mm/stroke.Thecuttingtimetoreturntimeratio
isgiventobe1.5andtheramcyclesavailableon
theshapersare28,40,60and90perminute.
Ans:choosing28strokes/min,time=44.65min

35. 20.Thesuggestedcuttingspeedforagiventool–workpiece
combinationonashaperis25m/min.Two300X200mm
surfacesofacastironblock400X300x200mmaretoberough
machinedonashaperusingHSStool.Afeedof0.5mm/stroke
maybeassumedforthiscuttingoperation.Ifthesetuptimeis
10minutespersurfaceandthelaborandoverheadchargesare
Rs150perhour,findthecostfmachining500blocks.Assume
return to cuttingtime ratioas 1:2.
Ans:neglectingclearance,takingL=300mmandusing56
strokes/min,Cost=Rs51,775.

36. 21.Inashaperwork,thelengthofthestrokeis
200mm,thenumberofdoublestrokes/minis30
andtheratioofreturntimetocuttingtimeis2:3.
Find the cutting speed.
Ans:10m/min