Shaping, Planing and Slotting Operations

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1 Shaping, Planing and Slotting Operations Chapter 7

2 Production of Flat Surfaces Typical components with flatsurfaces

3 Production of Flat Surfaces.. Motions for producing FlatSurface Cut Depth of cut E A ' A Feed B ' B C Workpiece D

4 Reciprocating Machine Tools differentfrom rotary machine tools A single-point tool moves linearly relative to the work part ShaperShapingtool moves PlanerPlaningworkpiece moves Slotter rkm2003

5 Shaper/Shaping Machine Tool Workpiece Vise Table f or d Tool head d or f Ram v Column Base rkm2003

6 Shaper/Shaping Machine Main Parts Base Column drive, support & guide ram Table hold & feed workpiece Ram tool head, clapper box Types of Shaping M/c Horizontal Shaper Vertical Shaper (Slotting M/c) rkm2003

7 Shaping Operation Cutting action and functioning of clapper boxin a shaper Clapper box rkm2003 Workpiece (a) Forward/Cutting stroke Tool cleared from machined surface (b) Return stroke Lifted clapper box

8 Shaping Operation..

9 Shaping Operation.. Machining of inclined surface on shaping machine θ Movement of the slide for feed Inclined machined surface θ Tool head & slide (axis parallel to machined surface) Clapper box (axis away from toolhead) Workpiece Tool holder located at a convenient angle Tool Depth of cut

10 Operating Conditions in a Shaping Machine cutting speed v = NL( 1+ m) 1000 m/min where N=the number of double strokes or cycles of the ram per min (one double or full stroke = one cutting and one return stroke) L=Length of the ram stroke in mm m = return stroke time/cutting stroke time

11 Operating Conditions in a Shaping Machine.. Cutting Stroke Return Stroke c Workpiece Lj c Clearance Length of stroke L rkm2003 Length of StrokeL= L j + 2 c

12 Operating Conditions in a Shaping Machine.. Feed f Feed f is the relative motion of the workpiece in a direction perpendicular to the axis of reciprocation of the ram Feed is expressed in mm/double stroke or simply mm/stroke because no cutting is done in return stroke rkm2003

13 Operating Conditions in a Shaping Machine.. Depth of Cut d Depth of cut d is the thickness of the material removed in one cut, in mm Depth of cut may be given by the tool head slide or by lifting the table rkm2003

14 f mm Machining Time w mm L mm rkm2003 Width cut in 1 stroke = f Total width = w No. of strokes to m/c total surface = w/f Strokes/mm = N Time for machining surface is t= w/(f N) min

15 Machining Time Time for machining w x Lsurface From cutting speed v= Machining time NL(1+ m) 1000 w t= min f N 1000v N = L(1+ m) w Lw(1+ m) t= = min f N 1000vf

16 Material Removal Rate Material removal rate(mrr) MRR = f d L N(1+m) mm 3 /min where d is depth of cut in mm f is feed in mm/stroke; Nis strokes/min L is length of stroke in mm m is ratio of return stroke time to cutting stroke time

17 Planer

18 Planer/Planing Machine Housing Tool heads Tool head Reciprocating table Bed Guideways Tool head

19 Types of Planing Machines Open Side Planer Double Housing Planer Edge planer Universal planer, Pit type planer rkm2003

20 Operating Conditions in a Planer Operating conditions in planer are similar to Shaping Machine Cutting Speed: Workpiece reciprocates cutting time=return time Cutting Tool: Multiple cutting tools cut simultaneously Job: Large size or multiple workpieces

21 Size of Shaping and Planing Machines Largest Size of Workpiecethat can be Machined Lxwx h rkm2003

22 Difference between Shaper and Planer Size of Workpiece Movement of Tool and Workpiece Construction Cutting and Return Speeds Number of toolheads

23 Slotting Slot made by slotting Ram Column Tool Table Tool holder Typical Job rkm2003 Base Slotter/Slotting Machine

24 Example 7.1 Find the machining time required for machining the surface mm, on a shaping machine. Assume, cutting speed as 8 m/min. The return to cutting time ratio is 1:4, and the feed is 2 mm/double stroke. The clearance at each end is 70 mm. Solution Lj= 600 mm, w = 800 mm, v= 8 m/min, m = ¼, f = 2 mm/stroke, c= 70 mm

25 Example Given clearance at each end: c=75 mm length of stroke: L= = 740 mm NL(1+ m) 1000v v= N = 1000 L(1+ m) = 8.65 strokes/min Assume 8.65 strokes/min available Machining time for 800 mm width rkm2003 t = f w N =46.25min

26 Example Alternately: t = Lw( v m) f = = ( ) min Assumptions: rkm2003 N?

27 Examples Example 7.2: Estimate the time required to machine a cast iron surface 250 mm long and 150 mm wide on a shaper with cutting-toreturn ratio of 3/2. Use a cutting speed of 21 m/min, a feed of 2 mm/stroke and a clearance of 25 mm. The available ram strokes on the shaper are: 28, 40, 60 and 90 strokes/min. Also, determine MRR assuming depth of cut as 4 mm. Solution Given data: Lj = 250 mm, f = 2 mm/double stroke, w = 150 mm, c= 25 mm, v = 21 m/ m/min, d = 4 mm The cutting-to-return ratio of 3/2 gives m = 2/3 rkm2003

28 Examples Given clearance is 25 mm, hence, L = = 300 mm. We know that (Equation (1)) SPEED v = NL(1+m)/ 1000 m/min From the above equation, we find number of double strokes Nper minute required as N = 42 strokes/min

29 Examples Nearest available ram strokes is 40 strokes/min. Since calculated value is more than 40, this is chosen. Normally, we should not exceed the specified cutting speed, as it will affect the tool life adversely. Hence, select N = 40 strokes/min. With a chosen value of N, we cannot use Equation (5) for time calculation. Hence, substituting all the values in Equation (6), we get t = 150 / (40 2) = 1.88 minutes

ROOP LAL Unit-6 Shaper & Planer Mechanical Engineering Department

ROOP LAL Unit-6 Shaper & Planer Mechanical Engineering Department Notes: shapers and planers Basic Mechanical Engineering (Part B ) 1 Introduction: Both shapers and planers are machine tools which produce a flat surface. They are capable of machining a horizontal, vertical