1. UNIT-I PLANING MACHINES

2. Planning machine

3. Planing machine

4. Another view of Planer

5. Table Movement in Planer

6. Table Movement in Planer- another view

7. What is a planer ? A Machine which produces flat surfaces
Consists a stationary housing for holding the tools
A table holding the work reciprocates
Large works, that con not be accommodate on shapers
The tool is stationary but the work moves

8. Planer - working principle
The table on which work is clamped is imparted a reciprocating movement
Cutting takes place during the forward stroke of table
During return stroke the cutting tool is slightly lifted
Tool is fed for each forward stroke
TOOL
WORK
Work is fixed on Table

9. WORKING PRINCIPLE – contd.
Table is driven by an electric motor
Length of table stroke can be adjusted
Speed of return stroke is also regulated

10. Principle of operation of a planer

11. Classification of planers
1. Double housing Planer
2. Open side Planer
3. Pit type Planer
4. Edge Planer or Plate Planer
5. Divided Table Planer

12. Double housing planer:
It is the Standard model & most widely used
Very heavy and robust
Has a bed and two vertical housings are fixed
Table moves along the guide ways of the bed
Housing supports cross rail & tool heads.
Cross rail carries two tool heads
Tool head carries tools

13. A double housing planer

14. Open side planer It has only one supporting column (housing)
Area larger than the table can be planed
Cross rail is mounted as a Cantilever
Tool holders are mounted on Cross rail
Stroke length of bed is controlled by adjustable dogs

15. Open side planer

16. PIT Planer
Columns and cross rail carrying tool head move longitudinally on massive rail above the work table
Bed is recessed in the floor
Loading and unloading of jobs is easy
Used for Planing heavy & large jobs
Table and work piece resting on it are stationary and the tool reciprocates

17. Edge / plate planer
Specially designed for squaring or beveling the edges of heavy steel plates for pressure vessels
Carriage supporting the tool is moved back and front direction
Cutting can take place during both directions of carriage travel
Operator stands on the platform & operates

18. Divided table planer Also known as Tandem planer
Planer has two tables on the bed
Table may be reciprocated together or separately
Each table reciprocates under different tool head
For continuous production, small work pieces clamped on one table are being machined, another is stationary and can be used for setting up fresh works
Used for quick & continuous production

19. Planing machine - parts
COLUMN
CROSS RAIL
TOOL HEADS
Feed Mechanism
TABLE
BED

20. Main Parts of Planing machine
1. Bed
2. Table
3. Housing or Column
4. Cross rail
5. Tool heads
6. Driving Mechanism
7. Feed Mechanism

21. Constructional details of a planer
CROSS MEMBER
COLUMN
COLUMN
CROSS RAIL
TOOL HEADS
Feed Mechanism
TABLE
BED

22. Parts of planer

23. Parts of planer

24. 1. Bed Large box like casting Length is nearly twice the table length
Consists guide ways on which table moves
Houses the driving mechanism of table
Made of Cast Iron

25. 2.Table Also called Platen
Large rectangular casting mounted on bed ways
Holds the work & reciprocates along bed ways
Top surface has T slots
Work is clamped on T slots

26. 3.Housing or Column Large vertical structures on each side of the bed
Supports cross rail on which tool heads are mounted
Also supports the mechanism for operating the tool heads
Made of Cast Iron

27. 4. Cross rail A rigid casting mounted horizontally on the column
Can be moved up & down by elevating screw
Carries two slides with tool heads
Tool heads can be moved horizontally on the guide ways of cross rail

28. 5. Tool heads Contains tool posts for holding the tools
Tool post (clapper block) is hinged to the head
During return stroke cutting tool will be lifted
Tool heads can be swiveled through 60º on either side of its vertical position

29. Specifications of a Planer
1. Distance between the two housings
2. Height between Table & cross rail at its
uppermost position
3. Maximum length of table travel
4. Number of Speeds & feeds available

30. Specifications of a Planer- contd.
5. Power input
6. Floor space required
7. Type of Drive
8. Net weight of the Machine

31. Mechanism Introduction
A Planing Machine produces flat surfaces
The Table holding the Work reciprocates
There should be some mechanism to move the Table in reciprocating motion, and
Table to move quick during idle stroke

32. Mechanisms to drive the Table (QRM)
1. Open & Cross belt drive
2. Reversible motor drive
3. Hydraulic drive

33. 1.Open & Cross belt drive Mechanism
Loose Pulley
Fast Pulley
Pulleys on Shaft
Counter Shaft
Open belt
Cross belt
19 - Table
Belt shifter
18. Trip dog
17. Belt shifter lever
9,12
Loose Pulleys
Rack
13 - Bull gear shaft
10,11
Fast Pulleys
14 - Bull gear
Change gears
Feed disc

34. Open & Cross belt drive Mechanism
Used for smaller capacity machines
Table is moved by gears & rack attached under
the table
Counter shaft at the top of housing has 2 pulleys
These Pulleys transfer power to main shaft(Driving)
Main shaft drives the table by rack & pinion

35. Open & Cross belt drive Mechanism
2 Sets of fast & loose pulleys are mounted on driving shaft at one end and pinion is on another end
RETURN STROKE:
Smaller fast pulley is used for backward motion of table (Quick motion)
It is connected by open belt drive
The open belt passes over small fast pulley to get Quick return
The Cross belt is on loose pulley so it will not drive

36. Open & Cross belt drive Mechanism
FORWARD STROKE:
Bigger fast pulley is driven by cross belt drive
It is used to drive the table during cutting stroke
Open belt is on loose pulley
At the end of cutting stroke, cross belt is shifted from fast pulley to loose pulley
Simultaneously open belt is shifted from loose pulley to fast pulley
This is achieved by trip dog which operates belt shifting lever
Thus the direction of movement is automatically reversed

37. Rack & Pinion used to move Table

38. 2. Reversible Motor Drive Mechanism
Electric motor drives the bull gear through gear trains
Motor is coupled to D.C. generator
When motor is started, generator supplies power to reversible motor

39. Reversible Motor Drive Mechanism
Reversible motor causes the planer table to move
At the end of stroke, trip dog operates the switch which reverses the direction of table
Speed of cutting stroke is reduced by regulating the field current of the generator

40. Reversible Motor Drive Diagram
A.C.driving motor
Reversible motor
Generator
Motor field resistance
Exciter
Motor field
Reversing switch
Generator field

41. 3.Hydraulic Drive of Planer
TABLE
Operating Cylinder
Speed
Control

42. Forward Stroke of Table
During cutting stroke, oil is pumped into LHS of cylinder
As the area is less due to presence of piston rod, less force acts
So the table moves slowly in cutting stroke
At the end of each stroke trip dog operates a lever
Lever actuates the control valve of circuit
TABLE

43. Return Stroke of Table Oil is pumped into the Operating cylinder
Cylinder contains piston & piston rod
The other end of piston rod is connected to the Table
During return stroke, oil is pumped into RHS of cylinder
More force acts on the piston & it moves quickly
TABLE

44. Cycle Repeated
Flow of oil is changed from one side to the other side of cylinder
The length of stroke can be varied by adjusting the distance between trip dogs

45. Planer Operations 1.Planing Horizontal Surfaces
2. Planing Vertical Surfaces
3. Planing Angular Surfaces / Dovetails
4. Planing Curved surfaces
5. Planing Slots, key ways & Grooves

46. Planing Horizontal Surfaces
Fix the work properly on the table
Set the required cutting speed
Give required feed of the tool
Give suitable depth of cut for rough cuts
Finishing the job by giving less depth of cut

47. Planing Horizontal Surfaces
CLAPPER BLOCK
TOOL
WORK
PLANER TABLE

48. Planing Vertical Surfaces
Fix the job on the table firmly
Align the surface to be machined properly
Vertical side is adjusted perpendicular to the table
Swivel the apron away from the job
Switch on the machine
Rotate down feed screw by hand to give down feed

49. Planing Vertical Surfaces
PLANER TABLE
WORK

50. Planing Angular Surfaces
Main angular planing is to make dove tails & V grooves
Set the work on the table
Swivel the tool head to the required angle
Set apron away from work
Give down feed as per requirement

51. Planing Angular Surfaces

52. Planing Formed Surfaces
Fix up a square nose tool in tool head
Required form is obtained by feeding the tool simultaneously in both hor. & ver. Directions
Give suitable depth of cut
This can also be done with the aid of a special fixture

53. Planing Formed Surfaces
TOOL
WORK
PLANER TABLE

54. Planing Slots & Grooves
Fix up the job on the table suitably
Fix Slotter tools in tool heads
Give feed using down feed screw
Move the tool by the required amount to get uniform slots / grooves

55. Cutting Rack or Splines
PLANER TABLE
WORK

56. Comparison between planer and shaper
Heavier, more rigid costlier machine.
Requires more floor area.
Work reciprocates horizontally.
Tool is stationary during cutting.
Heavier cuts and coarse feeds can be employed.
Work setting requires much of skill and take longer time.
Several tools can be mounted and employed simultaneously, usually four as a maximum facilitating a faster rate of production.
Used for machining large size work pieces.
A comparatively lighter and cheaper machine.
Requires less floor area.
Tool reciprocates horizontally
Work is stationary during cutting.
Very heavy cuts and coarse feeds cannot be employed.
Clamping of work is simple and easy.
Usually one tool is used on a shaper.
Used for machining small size work piece comparatively