Exercise : - Cutting Force

EXERCISE NO. 1

CUTTING FORCE MEASUREMENT

Manufacturing Technology Lab I III Semester A & B

AIM :

To measure the cutting forces for the given cutting conditions.

TOOLS AND EQUIPMENTS REQUIRED :

Lathe, Lathe Tool Dynamometer.

PROCEDURE :

1. The Lathe Tool Dynamometer is initially set to zero reading.

1. The known depth of cut is given and take the readings of Px and Pz force components from the Lathe Tool Dynamometer.

1. Calculate the resultant cutting force

P = Sqrt (Px2 + Pz2)

1. Repeat the same procedure to get few more readings and calculate the mean cutting force.

1. Repeat the same procedure for different depth of cuts.

RESULT :

Thus the cutting forces are measured for different depth of cuts.

TABULATION :

NOTE :

1. Pz – the main or tangential component, determines the torque on main drive mechanism, the deflection of the tool and the required power. This component acts in the direction of the cutting speed.

1. Px – the axial component, acts in the direction of the tool traverse and it is at right angles to Pz. It contributes very little to the power consumption.

1. Py – the radial component, acts along the tool shank and perpendicular to the other two components. It has no share in the power consumption.

EXERCISE NO. 2

SHEAR ANGLE MEASUREMENT

AIM :

To measure the shear angle to the given conditions.

TOOLS AND EQUIPMENTS REQUIRED :

Lathe, Single point turning tool, Micrometer.

PROCEDURE :

1. The workpiece is held in the chuck.

1. The known depth of cut is given (uncut chip thickness, t1).

1. The chip is taken for thickness inspection. Find the mean chip thickness, t2.

1. Calculate the chip thickness ratio, rc = t1 / t2

1. Calculate the shear angle for the given rake angle of the tool.

rc cos

tan  = ------

1 - rc sin where,  - rake angle.

1. Repeat the same procedure to get few more readings and calculate the mean shear angle.

1. Repeat the experiment for different depth of cuts.

NOTE :

1. The value of Shear angle depends on the cutting conditions, tool geometry, tool material and work material.

1. If the Shear angle is small, the plane of the shear is large, the chip is thicker, more force is required to remove the chip.

1. If the shear angle is large, the plane of shear will be shorter and the chip is thin. Hence, less force is required to remove the chip.

SHEAR ANGLE :

RESULT :

Thus the shear angle is found for different depth of cuts.

EXERCISE NO. 3

SURFACE GRINDING

AIM :

To grind the workpiece to the given tolerance using surface grinding machine.

TOOLS AND EQUIPMENTS REQUIRED :

Surface Grinding machine, Micrometer.

PROCEDURE :

1. The given workpiece is checked for its initial dimensions.

1. The permanent magnet worktable is cleaned thoroughly.

1. Keep the workpiece over the worktable and push the lever to “ON” position to hold the workpiece.

1. The required depth of cut is given by raising the table.

1. The reciprocating and cross feed is given to grind the required length and width of the workpiece respectively.

1. Finally, the finished workpiece is checked for the given dimensions.

RESULT :

Thus the given workpiece is ground to the given tolerance using surface grinding machine.

EXERCISE NO. 4

SPUR GEAR MILLING

AIM :

To machine gear to the given module and number of teeth in the given workpiece.

TOOLS AND EQUIPMENTS REQUIRED :

Milling machine, Vernier caliper, Mandrel.

PROCEDURE :

1. Calculate the gear tooth proportions.

Blank diameter = ( Z + 2 ) m

Tooth depth = 2.25 m

Tooth width = 1.5708 m

where,

Z = Number of teeth required

m = module

1. Indexing calculation

Index crank movement = 40 / Z

1. The dividing head and the tail stock are bolted on the machine table. Their axis must be set parallel to the machine table.

1. The gear blank is held between the dividing head and tailstock using a mandrel. The mandrel is connected with the spindle of dividing head by a carrier and catch plate.
2. The cutter is mounted on the arbor. The cutter is centred accurately with the gear blank.

1. Set the speed and feed for machining.

1. For giving depth of cut, the table is raised till the periphery of the gear blank just touches the cutter.

1. The micrometer dial of vertical feed screw is set to zero in this position.

1. Then the table is raised further to give the required depth of cut.

1. The machine is started and feed is given to the table to cut the first groove of the blank.

1. After the cut, the table is brought back to the starting position.

1. Then the gear blank is indexed for the next tooth space.

1. This is continued till all the gear teeth are cut.

CALCULATION :

Z = No. of teeth = 23

m = module= 2 mm

Blank Diameter= (Z + 2) m

= (23 + 2) 2

= 50 mm

Tooth Depth= 2.25 m

= 2.25 * 2

= 4.5 mm

Indexing Calculation = 40 / Z

= 40 / 23

= 1 17/23

RESULT :

Thus the required gear is machined using the milling machine to the required number of teeth.

EXERCISE NO. 5

CAPSTAN LATHE

AIM :

To machine the workpiece to the given dimensions using capstan lathe.

TOOLS AND EQUIPMENTS REQUIRED :

Capstan Lathe, Stopper, drill chuck, counter sink bit, drill bit, turning tool, parting off tool, Vernier Caliper.

PROCEDURE :

1. Prepare the tooling layout for the given workpiece.

1. Set the tools in their respective positions of the tool stations.

1. The workpiece is chucked and checked for the rotation.

1. The adjustment to the length of feed for each tool is adjusted by rotating the adjustment screws.

1. Feed the tools in the required sequence to machine the given workpiece.

RESULT :

Thus the given workpiece is machined to the given dimensions using capstan lathe.

EXERCISE NO. 6

ASSEMBLY - I

AIM :

To machine and assemble the given workpieces to the given dimensions using required machines.

TOOLS AND EQUIPMENTS REQUIRED :

Lathe, Turning tool, Parting tool, Threading tool, Vernier caliper.

PROCEDURE :

1. The given workpiece is checked for its initial dimensions.

1. The workpiece is chucked and turned for the required dimensions.

1. The external thread is made on the workpiece.

1. The internal thread is made on another workpiece.

1. Check for the mating of internal and external threads formed.

RESULT :

Thus the given workpieces are machined as per the given dimensions and assembled using the required machines.

EXERCISE NO. 7

ASSEMBLY - II

AIM :

To machine and assemble the given workpieces to the given dimensions using required machines.

TOOLS AND EQUIPMENTS REQUIRED :

Lathe, Vernier caliper.

PROCEDURE :

1. The given workpieces are checked for its initial dimensions.

1. The workpiece is chucked in lathe and machined to the projection dimensions as given in the figure.

1. The other workpiece is machined for recess dimensions as given in the figure.

1. Mate both the workpieces.

RESULT :

Thus the given workpiece is machined as per the given dimensions and assembled using the required machines.

EXERCISE NO. 8

MILLING OF HEXAGONAL SURFACE

AIM :

To machine a given hexagonal surface in a given workpiece using milling machine.

TOOLS AND EQUIPMENTS REQUIRED :

Milling Machine, Vernier caliper, Steel rule, Mandrel

PROCEDURE :

1. The given workpiece is checked for its dimensions.

1. The width across the flat is first determined ( Across flat = 1.5 S + 3 mm )

1. A universal dividing head is mounted on the table with its spindle swiveled to the horizontal position.

1. The workpiece is mounted at the nose of the dividing head spindle by the help of a suitable chuck.

1. The workpiece is centred below the cutter and the first cut is taken.

1. The workpiece is rotated through one sixth of a revolution by using the indexing mechanism and then the second cut is taken. It is to be repeated for six number of times to finish six faces of the workpiece.

RESULT :

Thus the required hexagonal surface is machined using the milling machine to the given dimensions.

CALCULATION :

Diameter, D = 2 x S

Distance across the Flat=(1.5 x S) + 3mm

Diameter (D) – Distance across the Flat

Depth of cut=------

2

INDEXING CALCULATION :

For Hexagonal surface, the number of faces, Z = 6.

40

Simple Indexing = ----

Z

40

=----

6

26

=6 ----

39

EXERCISE NO. 9

CNC LATHE

AIM :

To create a workpiece with the help of CNC Lathe Machine.