Q1
Fig. 1 Part drawing (All dimensions are in mm)
Solution
Q2 (a). Using a suitable schematic, show the various zones of deformation during the cutting
mechanism of chip formation. Also, identify and write the name of machining process shown in
following figures.
(a)
Solution
(a) Facing,
(b) Chamfering
© Boring
(b)
(c)
Q. 2(b). In an industry, a shaft is produced from a 200 mm long stainless steel rod
having 24 mm diameter by turning on a lathe in multiple passes which reduces the
diameter up to 20 mm. The reduction in diameter in each pass should not be more than
1 mm. The spindle of the lathe machine rotates at 350 rpm, and the tool has an axial
speed of 150 mm/min. Calculate the cutting speed (m/min), material removal rate
(m3/min) for each pass and total time required in minute for machining of the steel rod.
Sol.- Given data:
Lj = 200 mm,
D1 = 24 mm,
D2 = 20 mm,
N= 350 rpm
V= π×24 ×350/1000 = 26.389 m/min;
Depth of cut = 1/2= 0.5 mm
Number of passes n = (24 – 20)/(2x0.5) = 4
Feed rate = 200 mm/min, we get the feed in mm/rev by dividing feed rate by spindle rpm.
That is
f= 150/350 = 0.429 mm/rev
MRR= v*f*d = 26389 x 0.429 x 0.5 = 5660.52 mm3/min;
Machining Time Tm = 200 x 4 / 150 = 5.33 min
Q. 3(a). What do you mean by tool signature? Schematically show the angles of tool
signature 0-7-6-8-15-16-0.8 in different views of a single point cutting tool.
Sol.- Convenient way to specify tool angles by use of a standardized abbreviated system is
known as tool signature or tool nomenclature.
Rotary Pump:
Rotary pump is widely used pump in vacuum technology. It is mostlt used as a primary pump for baching
and roughing stages. It falls under gas transfer technology with positive displacemenrt characteristics.
The schematic is shown in figure below:
It consists ofa stationary part, Stator and a moving part, Rotor, assembled inside a casing. Moving
component is an accentrically placed slotted rotor, which turns inside cylindrical stator. Spring loaded
sliding vanes are mounted in the slots of the rotor. This rotor is driven by an electric motor as a constant
speed. Due to spring action, the rotor sliding vanes are in continuos contact with the stator walls, during
the rotation. Air is drawn into the pump through an inlet and it is compressed spring loaded exhaust
valves are used to expand this compressed gas this one operates only at a preset pressure to avoid the back
flow perfect ceiling is maintained by a thin fluid film existing between the moving contacts.
Four stages of Rotary pump is shown as in figure below:
First Stage: Introduction
Second Stage: Isolation
Third Stage: Compression
Fourth Stage: Exhaust