Good ppt for GTU doing mechanical engineering Glimpse about the Slotter and planar machine is given..in the ppt.drives used are also described in ppt.

1. Manufacturing process -1
Navroz Navodia(N3)

4.  Slotting machines can simply be considered as vertical
shaping machine where the single point reciprocates
vertically.
 The work piece is mounted on the table, it is given slow
longitudinal and / or rotary feed.
 The feed can be given by hand or by power.
 The circular feed permits machining of a curved surface
whereas the plane surface are cut by using either of the
table cross feed.

5. Slotter machine

6. Photographic view of slotter

8.  It is principally used for internal cutting like internal
cutting slots.
 For making keyways.
 Large internal and external gears can be machined using
indexing arrangement of rotary table.
 Keyseaters, a specially designed slotter is used to make
internal keyways.

9.  There are four types of slotter
1. Puncher slotters
2. General production slotter
3. Precision tools room slotter
4. keyseaters

10.  It is heavy rigid machine used for removing
large amount of metal from heavy forged,
stamped or roughly sawn work piece.
 It can remove surplus material from roughly
finished work piece.
 It can also finish the job.
 The ram is driven by a spiral clock and pinion
arrangement whereas the pinion is driven by
speed reversible electric motor.
 A square table is fitted for plane work whereas
round tables is fitted for circular cutting.

11.  These slotter have a
solid body that can be
tilted for machining
inclined surfaces.

12.  They are lighter high speed slotters and used
for tool room work with accurate machining.
 They are used for taking lighter cuts with
accurate dimension.
 Special jigs and fixtures are used to produce
large number of identical job.

14.  Keyseaters are
special type of
slotters
designed for
machining keys
in wheel and
gear hubs.

15.  There are generally four drive mechanism.
1. Slotted disc mechanism
2. Variable speed reversible motor drive
3. Hydraulic drive
4. Slotted link drive.

16.  The pinions which is in mesh with main gear gets its
motion from the drive motor through belt drive.
 The gear is coupled to the slotted driving disc.
 The circular motion of the slotted disc is converted into
the vertical reciprocating of the ram with the help of
connecting rod.
 The stroke length can be changed by changing the
position of crank pin relative to center of slotted disc.

18.  A range of ram speed is obtained with the
help of multispeed gear box provided with
motor.
 It is used in large modern slotters

19.  Hydraulic drive is used for precision work
 The piston axis vertical in this drive instead
of horizontal used in shapers but the rest
arrangement is similar.
 This drive is smooth and free from vibration.

20.  Slotted link drive is used for heavier type of
slotting machine.
 The drive from the electrical motor is transmitted
to helical stroke wheel through a gear box and
clutch.
 The wheel carries a bronze sliding die block
which slides on the face of a large oscillating link
connected to the ram of the slotter.
 The stroke of the slotter is adjusted by varying
the radius at which the sliding die block rotates
with the stroke wheel.
 The vertical position of the ram can be changed
through a pair of bevel wheels.

22.  It is a machine tool designed to
machine metal by combining
the line motion of a job and
the perpendicular feed of the
tool.
 The type of work is similar to
that done on shaper but it takes larger
workpeices.
Double housing planer

23.  They are of six types
1. Double housing planar
2. Open side planer
3. Universal planer
4. Pit type planer
5. Plate or edge planer
6. Divide Type Planer

24.  It is the most common type of planer.
 It consists of mainly a massive bed on which the
worktable reciprocates, and two vertical columns or
housing, one on each side of the bed.
 Each column carries a tool head that can be slide up and
down on the column.
 A cross rail fitted between the two columns may carry
one or more tool heads that can slide horizontally on
the cross rail.
 All the tool heads can be clamped in position, and can
be used collectively or individually depending on the
requirements.

25.  Open side planer consists of only one vertical
column or housing on which the cross rail is
mounted.
 The column and the cross rail carry single
and double tool heads respectively.
 This type of machine permits machining of
wide work pieces.

27.  The main feature
of a universal
planer is that it
can cut on both
forward and
reverse strokes.
 Different cutting
edges operate for
cutting in the two
strokes.

28.  A pit type planer differs from other planer in the
sense that, the table and the work piece resting on
it remain stationary and the tool reciprocates
across the work surface.
 This type of machine is preferred for very large
work, where the weight of the work piece and the
tool required table would make reciprocating
movement difficult.
 The job is either mounted on a stationary table, or
on the floor inside a pit, and hence the name pit
type planer.

29.  One or two tool heads can be mounted on the
cross rail and two side tool posts the housings,
if required.
 The entire unit travels along the horizontal
ways and fro and, thus the tool moves past the
work surface during operation.
 All feeds are automatic and reversible and are
designed to operate either at both end of the
planing stroke or at one end only.

30.  This type of machine is used for machining the
edges of heavy workpieces.
 The workpiece is clamped on the bed and the
side mounted carriage supporting the cutting
tool is reciprocated along the edge of the
workpiece.
 Cutting can take place during both directions
of carriage travel
 A large screw drive is used for moving the
carriage.

31.  It is also called tandem planer and consists of two worktables,
which may be reciprocated together or separately.
 It is quite well known that, mounting and setting of work pieces
on the worktable consumes more time thereby restricting the
machine for continuous mass production applications. In such
cases, divided table planer can be used, where in, one
worktable can be used for setting up a new work piece, while
the second worktable carrying work piece is being machined.
 The two tables can be joined together to hold large work pieces.

32.  There are different planer drive mechanism
such as
1. Open and crossed belt drive
2. Table drive by reversible motor

33.  Four pulley belt drive
 Two pair of loose and fast pulleys are driven at
different speeds from the same pulley with
open crossed belts.
 At the end of each stroke a belt shifter changes
the position of both the belts simultaneously
thereby reversing the table
 To reduce the slip and angle of lap the cross
belt is used for forward motion.

34.  Three belt pulley drive
 The central pulley is loose on the shaft while the
two outer ones are fixed.
 Drive between two shafts is through gears and an
additional gear is there on one side for reversal
motion.
 At the end of each stroke the belt shifter shifts
the belt from one to other
 The loose pulley enables the machine to be
stopped temporarily for checking the job without
having to stop the driving motor.

36.  Many planers are equipped with a variable
speed electric motors for driving the bull gear
through a train of gears
 The speed and direction of the rotation of the
D.C motor can be easily controlled with
suitable controlling devices.

37.  The feed mechanism is provided intermittently
between two strokes.
 Cross feed and down feed are given on the
tools on the cross rail.
 The down feed is needed for machining vertical
and angular surface while cross feed is given
while machining horizontal surfaces.
 Both feed are given with the help of screw and
nut mechanism and can be given manually or
automatically.

38.  The automatic feed drive for a planer are
provided by two methods
1. By friction disc
2. By electric drive

39.  It consists of a friction disc D at the bottom and a rack and
pinion drive at the top.
 The friction disc D is connected to a table drive shaft with a
flexible connection formed through leather washers.
 A T-slot is cut radially on the face of feed disc within which
block B slides over a screwed shaft.
 At the end of screwed shaft is a knurled knob K which can be
turned to adjust the position of block B with respect to the
centre of the disc.
 The sliding block is connected at one end to a connecting rod
C which at the other end is connected at the rack R through a
guide G.
 A projection pin connected to the disc body extends beyond
the body of the disc.

40. ‣ When the table drive shaft starts rotating during the cutting
stroke the motion is transmitted to the disc but when the
projecting pin hits a fixed pin P1 fitted to a machine body,
the disc starts slipping even though the drive shaft
continuous to rotate.
‣ When the table is reversed the disc rotates through the same
angle in opposite direction due to the projecting pin hitting
the second fixed pin P2.
‣ The rotary motion of the feed disc is transmitted through
rack R to pinion L mounted on shaft S1.
‣ Gears G1 and G2 are mounted on shaft S1,butG2 is keyed to
shaft while G1 is free.
‣ Double pawl M is pinned on face of G1 and any one end of
pawl is meshed with gear G2.

41. ‣ When left end of pawl is meshed with G2, upward movement
of rack rotates gear G2 in clockwise direction and also
rotation of gear G1clockwise because of pawl connection.
‣ Downward movement of rack will move gear G2 in
anticlockwise direction but no motion is transmitted to G1
because pawl’s bevel edge will slip over teeth of gear G2.
‣ Gear G1meshes with gears G3 and G4 mounted on shafts S2
and S3 which are down feed and cross feed shafts of planer.
‣ The feed motion is transmitted to tool heads by shafts S2 and
S3.
‣ Direction of feed movement can be reversed by changing
position of double pawl.
‣ Amount of feed can be varied by operating knurled knob K
which changes eccentricity of block B.

43.  Modern planer which have an electrical drives
also use an electrical feed mechanism.
 A separate motor is used on these planer to
provide feed motion.
 The motor is energised at the same time as
the table reversing mechanism and rotates
through different part revolution after which
it is automatically tripped.

44.  For best planer use many tool head should be
used as possible.
 For roughing and finishing cut , the first tool
may do roughing cut and other tool head may
follow it doing finishing cut.
 If the medium sized parts are lined up in a row
on the planer table and are machined at the
same time ,it is known as string or multiple
machining.
 Planer tools are same as general type of lathe
but they are heavier in construction.

45.  The common operations include Planning of:
1. Horizontal flat surface
2. Vertical flat surface
3. Planning at an angle
4. Planning at curved surface
5. Planning different type of slot, grooves etc.

46.  In shaper the work piece is held stationary on the
table while in planer tool is stationary and work piece
moves back and forth.
 Planer holds heavier work pieces compared to shaper.
 A planer is heavier and can give much heavier cuts
compared to a shaper.
 Shaper uses one cutting tool while planer using
several cutting tool simultaneously.
 The drive on a shaper is slotted lever crank
mechanism while planers are operated by fast and
loose pulleys.
 Planers give better accuracy than shaper because of
their better rigidity.
 Shaper is more economical for cutting small and
medium size work pieces.
 Work piece can be clamped in shaper more easily
compared to planner.