This is a six week summer training report for B. Tech. Mechanical Engineering on HMT Machine Tools, Pinjore. for direct download links, visit my blog by opening below address and click on "skip ads" after 5 seconds (on top right corner of screen). Blog address - http://adf.ly/3108600/hmtreport Thanks

1. ACKNOWLEDGEMENT
I would like to thank the entire HMT limited who has
provided me this six weeks training. I am thankful to the
HRD officer of training centre who organized my training
schedule and also the DGM‟s and AGM‟s of various shop
departments who have provided me the various knowledge
about their respective shops.
I also thanks to the workers of their respective
departments, who were always ready to clarify our doubts
and helped us to increase our knowledge by illustrating us
to the finer points.
I wish to express my deep gratitude to all the
concerned persons, whose co-operation and co-ordination
have given me the success to complete my training in
organization.
I hope that my report will reflect our technical
knowledge and innovativeness, which we gained at HMT
Pinjore.
[1]

2. PREFACE
Industrial training is part and parcel of every technical
course and gives a face or form to all the theoretical
knowledge we gain in our classroom. We get to have a
virtual experience of the processes, methods, objects and
phenomenon which used to be just an imaginary picture in
our minds. It also gives an exposure to the environment of
the industries and workshops which are virtual components
of our professional life. We too were provided with this
opportunity this summer.
We are thankful to our college administration that
handed this invaluable chance to us and at the same time
we pay our regards to the administration of HMT Pinjore
(Machine Tools Division) that proved to be a great
supporting force for the fulfillment of the purpose. The
officials and the workers of the firm provided us with the
best of their attention and share ample of knowledge of
their concerned field with us.
[2]

3. INTRODUCTION
Fulcrum of Indian Industrial Development:
HMT synonymous with excellence in precision
engineering is a multi product company established in
1953. Built on a strong foundation of technical know how
acquired from world leaders in machine tools such as
Oerlikon, Manurhin, Glidemeister, Liebherr, Rino Berardi,
Fritz Werner, Pegard, Waldrich Coburg etc. HMT‟s
machine tools expertise has been developed to such an
extent that HMT can design and develop any kind machine.
Having established as a machine tool manufacturer, HMT
diversified into other product lines.
From simple lathes to multi-station transfer lines from
stand alone CNC machine to flexible manufacturing
systems, leading to factory automation, HMT‟s broad range
of machine tools cover General Purpose Machine, Special
Purpose Machines and CNC machines, meetings the
application needs to every engineering industry.
Pioneering the concept of CNC technology in India
HMT has the destination of being the first company to
successfully manufacture its own CNC system in
association with Siemens.
HMT‟s commitment to the development of the
machine tools technology is clearly reflected in the fact that
HMT has as many as seven exclusive machine tool units,
[3]

4. spread across the country. Each superbly equipped to meet
the most challenging demand for machine tools. These
units are in Banglore, Pinjore, Kalamassery, Hyderabad,
and Ajmer are all ISO 9000 certified.
Today HMT is well positioned at the fore front of the
precision engineering field. Its manufacturing plants
employ highly skilled workforces strongly supported by
R&D. Today over 780000 machine tools manufactured by
HMT are in used in India and elsewhere.
In tune with changing business environment, HMT
limited restructured into holding company tractors as its
core business and the following subsidiaries:
 HMT Machine Tools Limited,
 HMT Watch Limited,
 HMT Bearings Limited,
 HMT Chinar Watches Limited,
 HMT (International) Limited,
 Praga Machine Tools Limited.
[4]

5. The Pinjore Unit:
After having established two machine tools factories
and a watch factory in Bangalore, the Pinjore Unit was
established as the third machine tools factory. It went into
production on 1st Oct. 1963. This factory has been
designed, built and commissioned entirely by Indian talent
in a record period of 17 months of breaking the ground on
May 2, 1962. Pundit Jawaharlal Nehru, The first Prime
minister of free India, inaugurated it on Oct. 28, 1963. Later
in June 1971, HMT‟s Tractor project commenced its
operation here.
Machine Tools Division:
The unit was initially planned for manufacturing
Milling Machines. To begin with, foreign designed
capabilities, HMT‟s self designed machines were
introduced. Today the range includes carious types of knee
as well as turret ram types of Milling machines Rugged and
versatile, these machines offer wide spindle speeds and
feeds. With high contents mechatronics, Milling machine
with predefined programme upto 40 steps have been
introduced.
In 1969 manufacture of Broaching Machines was
taken up as import substitution. Available in horizontal and
vertical versions, these ruggedly constructed machines have
infinitely variable cutting speeds with dead constant speeds
ensuring optimum tool life and fine surface finish.
[5]

6. In tune with HMT‟s commitment to usher in the latest
technologies to the country‟s fast developing industrial
base, in 1976 the unit introduced the state of art
computerized numerically controlled machine offering
unlimited option in unmanned manufacturing concept.
The unit has designed a wide range of both Horizontal
and Vertical CNC Machining Centre to meet the stringent
accuracy standards, providing high flexibility and
productivity with enough muscle to remove large quantities
of material at low RPM for steel and high RPM for light
metal alloys. High processing speed is ensured through
CNC Systems that have powerful graphics and userfriendly features. The machine can be integrated with other
machine tools into flexible manufacturing line. The unit
also manufactures moving column type Special Purpose
Machines which can perform milling, drilling, tapping,
boring and reaming operation with re-circulating linear
motion bearing for high position accuracy with the encoder
„x‟, „y‟, and „z‟ axis.
Beyond Machine Tools:
HMT also manufactures metal forming presses and
press brakes, die casting & plastic injection moulding
machine, printing presses, wrist watches, tractors, bearings,
food processing machinery and a host of other engineering
products. Besides, HMT has proven expertise in Turkey
projects both within the country and outsides.
[6]

7. PATTERN SHOP
A pattern may be defined as a replica or facsimile
model of the desired casting which, when packed or
embedded in a suitable moulding material, produces a
cavity called mould. This cavity, when filled with molten
metal, produces the desired casting after solidification of
the poured metal. Since it is a direct duplication, the pattern
very closely conforms to the shape and size of the desired
casting, except for a few variations due to the necessary
allowances.
The most commonly used pattern materials in the
industry are 1) wood (e.g. teak, deodar etc.), 2) metal (e.g.
aluminium, cast iron, bronze etc.), 3) thermocol, 4)rubber,
5)epoxy resin.
Wood:Wood are used for pattern making are of either teak or
deodar or both of them. When both of them are used, then
teak is generally used on the inner sides because teak is
harder and retains it‟s shape for longer times as compared
to deodar which secretes a resign that on solidification can
effect the shape of the pattern which when used gives
defective casting.
[7]

8. Comparison of Teak and Deodar:
1. Teak is easier to work in milling operation.
2. Teak is harder in comparison with deodar.
3. Teak has longer life so it is used in making patterns of
those tools which are to be manufactured in large
numbers.
[8]

9. FOUNDARY SHOP
HMT‟s foundary shop comprises of two units:
One is the captive foundary, meant for the small
production of casting having weight upto 4 tonnes.
The capacity of this foundary is 1000 MT per annum.
And the other is meant for mass production of
comparatively smaller tractor and machine
components. The capacity of this foundary is 2000 MT
per annum.
Melting Department:
The process of melting in HMT is carried out in
induction furnaces at a temperature of about 1400°-1450° C
Process:
At first the induction furnaces are coated with fine
cement clay. Now metal scrap is inserted in the furnace and
slag coagulant is added to it. The requisite amount of coke
is added to it. The current is supplied to copper coils
provided in the furnace which induce current in the metal
scrap and the scrap gets heated up, when the melting
temperature is reached the molten metal is collected in
ladles and taken to the pouring zone. When this process is
being carried out the copper coils are regularly cooled with
[9]

10. coolant (water) so that the coils do‟not melt due to the high
temperature generated in the coils.
The foundary of HMT has three furnaces, two, each
having capacity of 3MT and one of 1.5MT. The two types
of induction furnaces are:Main frequency Induction Furnace(50Hz)
Medium frequency Induction Furnace(250Hz)
Melting of metal ion medium frequency furnaces are faster
than the main frequency furnaces.
Specifications of 1.5 tonne capacity furnace:Line Voltage
:
11000 Volts
Primary Voltage
:
440 Volts
Power Voltage
:
440 KW
Power Rating
:
5 KA
Melting Power
:
1 tonne per hour
Frequency
:
50 Hz
Lining Thickness
:
95 mm
Power Factor
:
0.9
After the melting process is complete, the molten
metal is carried quickly to the moulds to prevent
solidification. The inversion of Induction Furnaces is
[10]

11. carried out by hydraulic lifts fitted just below the whole
apparatus.
Moulding and Core Making:
In HMT due to complex structure of components (such
as gear box) are produced with the help of master pattern.
Here core is first made with the help of master pattern after
which the core is allowed to be baked.
The core is made with the help of sand such as
Rigid coated sand in shell core machining.
Air setting sand or no bake sand.
Green sand.
Here the gear box is made with no bake/air setting sand
which is prepared by mixing different constituents.
Here the prepared core (made from master pattern) is
allowed to solidify.
Smaller core is baked with the help of shell core
machine, which has a box containing rigid coated sand.
When allowed to operate the front assembly rotates and
the box moves upward from which the sand falls in the
die (die used according to shape of core required) here
die can be changed.
Now the core is put in cope, drag and the molten metal is
poured after which pattern can be easily obtained.
[11]

12. Fettling:
Fettling is the process by which the pattern obtained is
given the desired finish by various processes. Before
fettling, the casting obtained is subjected to removal of
projections, chips, core, runner, riser etc. by the
following processes:
Decoring
Chipping
Shot blasting (for heavy pattern)
Wheel abrasion (for small pattern)
Decoring:
Decoring is the process of removing the fused sand.
Chipping:
Chipping is the process of removing the runner, riser
etc.
Shot Blasting & Wheel Abrasion:
Shot blasting or wheel abrasion is used for removing
the sand particles by the usage of air.
After this fettling is done by the following process:
Pneumatic gun- to remove corner sand.
Angle grinder- to give corner finish.
Die grinder- to give finish to inner portion.
Pedestal grinder- to give surface finish.
[12]

13. While making casting for gears, surface finish is not
required because gear has to be cut on it with the help of
milling machine after which it is grinded.
PRIMING & PAINTING:
After clean and fettling, the casting is subjected to
priming and painting to prevent corrosion.
[13]

14. SMALL PARTS AND HEAT TREATMENT
This section of machine tool, HMT is primarily
concerned with the manufacturer of small parts of machine
tools. The machines concerned are CNC machines, lathe
machines, milling machines, drilling machines etc. This
department requires precision work.
Since there are number of small parts for number of
machines and of different shapes, therefore this department
is further divided into different subsections. They are:
1 Spindle section
2 Turret section
3 Round section
4 Gearing section
5 Non round section
6 Sheet metals section
Spindle Section:
This section is concerned with the manufacturing of
small cylindrical parts or spindles which may be hollow,
solid, shell type etc. according to machine‟s requirement.
The jobs concerned are larger in size as compared to other
sections. This section manufactures all the head related obs.
This machine requires for the purpose include lathe
[14]

15. machines like LB26 lathe, centre lathe, turret lathe. Also
use of drilling machine is there .Thread cutting operation is
also carried out in this section. The job to be worked upon
is supplied by the foundry department.
Examples of the parts manufactured:- Bearing housing
,main spindle , shafts, cam, sleeves etc.
Turret Section:This section is concerned with small job construction.
These jobs requires precision works since these parts are to
be fitted in small areas and generally screwed up the
machines involved in this process are lathe machine and
use of precision measuring instrunments like digital
micrometer, dial vernier calliper etc.
Examples of parts manufactured:- nut, bolts, clamping
screw, pins, holder, micro nuts etc.
Round Section:This section concerned with the round job construction
and working. The section involves operation like grinding,
slotting, drilling etc.
Following are the lists of machines and operations
concerned with them:-
[15]

16. Internal Grinding Machines:Concerned with grinding of inner surface of job.
Surface Grinding Machines:Concerned with outer surface of job. It uses magnetic
chuck and shows only horizontal motion of the table at the
bed.
Rotary Grinding Machines:Concerned with horizontal as well as rotational
movement of the table. It also uses magnetic chuck.
Cylindrical Grinding Machine:This is used to grind cylindrical jobs with the motion
of grinder itself. This job is held in the jaw chuck.
Slotter:This machine is concerned with slot cutting. It uses
carbide tip and shows vertical motion of the tool for slot
cutting.
The other machines concerned with this section are lathes,
drilling machines etc.
[16]

17. Gearing Section:Gear is used for power transmission of different parts of
machines. This section is concerned with teeth cutting.
Proper indexing is maintained in the process with fixtures
on the machines concerned. There are four types of gears
used in manufactured here:1. Spur gear
2. Worm gear
3. Helical gear
4. Bevel gear
The various machines involved are:-
Milling Machine:Generally used for manufacturing of spur gears.
Cutters of prescribed sizes are used.
Gear Hobbing Machines:Gear hobbing machine is used for manufacture of
worm gear. It uses hydraulic action.
Broaching Machine:Broaching machine is used to put splines in gear.
[17]

18. Gear Teeth Grinding Machines:It is used for grinding the teeth of the gears. In this
machine gear teeth are grinded by a worm type grinding
wheel. Here the tooth profile are checked with a machine
called gear tooth profile tester.
Non- Round Section:
All the non-round jobs that are to be used in machines
are machined here.
Components Manufacturing:
Blocks, rectangular strips, gibs, pump body, stop
block, adjustable plate, clump levers etc.
Operations Performed:1. Marking
2. Vertical milling
3. Drilling
4. Fitting
5. Grinding
[18]

19. Machines Used in Section: Horizontal milling machine
 Vertical milling machine
 Surface grinding machine
Sheet Metal Section:
This section includes the cutting of sheets, bending of
sheets at various angles. Various operations like drilling,
bending, shearing etc, are completed in this section. Some
of the areas where sheet metal are used are:
1. For outer body manufacture.
2. For making junction boxes in CNC machines.
Machines Used in Section: Radial arm drilling machine
 Nibbling machine
 Bending machine
 Shearing machine
 Nc machine
[19]

20. MATERIAL TESTING
1) UNIVERSAL TESTING MACHINE:
It has component load scale, oil pump, hydraulic press,
main piston, fixed cross head, & movable cross head. It
has range according to load applied:
a) 0-1 tons
b) 0-4 tons
c) 0-10 tons
It is generally used to determine:
 Proportional & elastic limit
 Yield point
 Ultimate tensile strength
 Percentage elongation & reduction of area
Working:
It is generally used to perform tensile test which is
widely used in the design of material for structure & other
purposes. Here, test piece is pulled out at a constant rate
gradually increasing the axial pull, till the rupture take
place. The tensile test for ductile material is generally,
carried out with the help of a Universal Testing Machine on
the specimen made from material to be tested.
[20]

21. 2) SPECTROSCOPE:
It is a method of qualitative analysis of material with
the help of electricity. Argon gas is being used as it
prevents oxidizing of piece. Here piece is not destroyed.
This is used for chromium, ammonium, nickel, tungsten,
manganese, zinc, tin, lead etc. the spectrum is directly
compared with a chart as it is moved by caliper & is then
compared. It is used to find what materials are present.
3) SPRING TESTING MACHINE:
In this machine, spring test is done. We will find out
compression or extension of spring & the load applied
which is noted from load indicator. Then we calculate
spring stiffness.
4) POLISHING MACHINE:
In this machine polishing of material is done. In this
belts are present on which abrasive powder is applied. In
this machine belt is passed over two pulleys & which is
driven by motor.
5) MAGNETIC CRACKING TEST:
[21]

22. In this method, magnetic crack test machine is used. It
is to check cracks b/w two pieces. We take two pieces
which are magnetized followed by spraying the iron
chips. The ultra violet light marked & fluorescent color is
produced. Then Iron piece is glows due to ultra violet
light.
6) SPECTOMETER:
It is basically computerized control program in which
material is kept under observation than software is there
which give composition of each element present in the
material.
7) PORTABLE MICROSCOPE:
It is a method used for analysis of the structure without
cutting. And also it is used for determining the
composition of element present in the material. It is used
for the analysis of the structure.
8) CARBON TASTING APPRATUS:
It is chemical method of analysis of the material. In
this, we take test sample of 1gm of carbon in the silica
boat which is put in silica pipe. This is now passed
through furnace which is at 1000 deg Celsius. Now
oxygen gas is passed & then carbon dioxide (CO2) is
[22]

23. formed which dissolves in alkaline solution than value is
raised to corresponding exhaust temperature. Then
carbon content is determined as:
CARBON CONTENT = 0.3×CORRECTION FACTOR×VOLUME READING
9) ROCKWELL HARDNESS TEST:
The Rockwell hardness test is generally performed
when quick & direct reading is desirable. This test is also
performed when the material have hardness beyond the
range of Brinell hardness test. In this test the load for
making indent are smaller & thus make smaller
shallower indent. It is because of this reason that the
Rockwell hardness test is widely used in industry. This
test has nine scales of hardness (A to H & K). But B & C
scales are widely used. The ball indenters are generally
made of hardened tool steel or tungsten carbide. During
the test, the specimen is placed on anvil, & raised till it
comes in contact with indenter. A minor load of 100 KN
is applied on the specimen & the small pointer indicates
set. Now the main pointer is also brought to the set
position. The major load is then applied & is allowed to
continue for one second. The depth of indentation in mm
is read from the smaller pointer.
[23]

24. 10)VICKER HARDNESS TEST:
The Vicker Hardness Test is the most accurate test
which has a fairly continuous scale of hardness. The test
makes the use of a diamond square based pyramid
indenter. A piston & a dashpot of oils used for
controlling the rate & duration of the loading. The test is
performed by placing the specimen on an anvil & raised
till it is close to the indenter point. The load is then
gradually applied to the indenter & then removed. This
test is very suitable for testing polished & hardened
material or nitride surface due to small impression made
on the test specimen.
PRECAUTION:
The indenter & anvil should be clean & well placed.
The surface of the specimen should be flat, clean, dry,
& smooth &should be placed perpendicular to the
indenter.
[24]

25. M CODES
M00 Program Stop
M01 Optional (Planned) Stop
M02 End of program
M03 Spindle CW
M04 Spindle CCW
M05 Spindle OFF
M06 Tool change
M07 Coolant #2 ON
M08 Coolant #1 ON
M09 Coolant OFF
M10 Clamp
M11 Unclamp
M12 Unassigned
M13 Spindle CW & Coolant ON
M14 Spindle CCW & Coolant ON
M15 Motion +
M16 Motion M17 Unassigned
M18 Unassigned
M19 Oriented spindle stop
[25]

26. M20-M29 Permanently Unassigned
M30 End of tape
M31 Interlock bypass
M32-M35 Unassigned
M36-M39 Permanently Unassigned
M40-M45 Gear changes if used, otherwise unassigned
M46-M47 Unassigned
M48 Cancel M49
M49 Bypass override
M50-M89 Unassigned
M90-M99 Reserved for user
[26]

27. G CODES
G00 Rapid Positioning
G01 Linear Interpolation
G02 CW circular Interpolation
G03 CCW circular Interpolation
G04 Dwell
G05.1 Q1 Ai Nano contour control
G05 P10000 HPCC
G07 Imaginary axis designation
G09 Exact stop check
G10/G11 Programmable Data input/ Data write cancel
G12 CW Circle Cutting
G13 CCW Circle Cutting
G17 X-Y Plane selection
G18 X-Z Plane selection
G19 Y-Z Plane selection
G20 Programming in inches
G21 Programming in mm
G28 Return to home position
G30 2nd reference point return
G31 Skip function
[27]

28. G33 Constant pitch threading
G34 Variable pitch threading
G40 Tool radius compensation off
G41 Tool radius compensation left
G92 Programming of absolute zero point
G94/G95 Inch per minute/ Inch per revolution feed
G96 Constant surface speed
G97 Constant spindle speed
G98/G99 Return to initial Z plane/ R plane in canned cycle
[28]

29. HEAVY PARTS AND TOOL ROOM
INTRODUCTION:It is the shop which gives the shape to the largest
castings which come from the foundary after being painted
rough. In this section various operations are performed by
the help of planers, boring and planning-boring machines.
In this section, first of all the jobs are checked for the
castings to be over-size or undersize. If they are undersize,
they are sent to scrap. If they are oversize, they are marked
and sent for machining.
Different types of operations are done by using
different machines including various measuring devices.
This section also includes in itself a high technology
section in which advanced machines are placed to machine
crucial parts generally guide ways etc. It accommodates a
tool preset device which is used to set the tool of all
machines and CNC machines. It is used to measure the
length and diameter of the tool with the help of leases.
This section is generally divided into two
sections:
Planning
Boring
[29]

30. Planning:This section consists essentially of planers mounted on
one side of the section. In this section the job planning is
one of the basic operations done for machining process. It
is primarily intended for machining large flat surfaces.
Machines Installed
Double Housing Planer
Open Side Planer
Plano Milling Machining
Horizontal Turning Centre
1) Double Housing Planer:This is the heavy type of planer and is used for heavy
cuts by double cutters. Its length is 3000mm. It consists of
two columns, one on each side of bed. The cross rail is
fitted between the two housings which can accommodate
one or two heads, according to the specifications.
2) Open Side Planer:This type of planer consists of a single column situated
vertically on one side of the bed and other side is left open
without any column.
[30]

31. The cross-rail is wholly supported on the single
column. Only one tool head can be located on it as there is
only one column.
3) Plano Milling Machine:This is similar to a double housing planer but the tool
can be milling tool. One of the machines is TNC (three axis
turning centre) in which only one axis can be moved at a
time. Thus round jobs cannot b machined here.
Another machine is CNC in which two axis can be
moved simultaneously to machine round job. The length of
the bed is 2800mm.
Boring:Boring is the operation of enlarging an already drilled
hole. The holes are pre-drilled as in casting only.
Machining time in boring:Machining time is the time required to complete the
work place in a request period of time.
Time required = Length of cut/(RPM × feed per meter)
Machines installed
Horizontal Boring Machine
[31]

32. Vertical Boring Machine
Jig Boring Machine
Horizontal Boring Machine
In the horizontal boring machine, operations are
performed on those large components which cannot be
rotated. The spindle and the boring bar are horizontal.
It has mechanical system and fixture is attached with
table. The work table can be transverse along and across the
machine bed.
Vertical Boring Machine
The spindle is vertical and bores vertical holes in the
spindle. The size of the machine is determined by
maximum length of the job which can be machined on it.
The machine can also be used as a drilling machine.
Jig Boring Machine
Jig boring machine is used to accurately enlarge
existing holes and make their diameters highly accurate. Jig
boring can also maintain high accuracy between multiple
holes and surfaces.
[32]

33. Tolerances can be held readily within ±0.002mm. The
machine can also do accurate milling, reaming, drilling and
facing,
In general, the vertical jig boring machine employs a
precision vertical tools spindle and coordinate work table
with a great accuracy. The position measuring system
consists of accurate lead screw with micrometer and an
optical scale along with a vernier.
The machine are of rail type i.e. they are constructed
with a cross rail that is supported and adjusted vertically on
two columns. The cross rail serves to carry vertical spindle
in its housing along the transverse axis.
[33]

34. TOOL ROOM
This department keeps various kinds of tools which
are useful during manufacturing of heavy pats. Most of the
tools are measuring devices such as vernier caliper,
micrometer etc.
Vernier Caliper:A vernier caliper is a device used to measure the
distance between two symmetrically opposing sides.
The tips of the caliper are adjusted to fit across the
points to be measured, the caliper is then removed and the
distance read by measuring between the tops with a
measuring tool, such as a ruler. Vernier calipers can
measure internal dimensions (using the uppermost jaws in
the picture), external dimensions using the pictured lowered
jaws and depending on the manufacturer, depth
measurements by the use of a probe that is attached to the
movable head and slides along the center of the body. This
probe is slender and can get into deep grooves that may
prove difficult for other measuring tools.
The vernier scale may include both metric and inch
measurements on the upper and lower part of the scale.
Vernier calipers commonly used in industry to provide
a precision to a hundredth of a millimeter (10 micrometers),
or one thousandth of an inch.
[34]

35. Parts of Vernier caliper
Outside Jaws: used to measure external diameter or
width of an object
Inside Jaws: used to measure internal diameter of an
object
Depth Probe: used to measure depth of an object or an
hole
Main Scale: gives measurements of up to one decimal
place (in cm)
Main Scale: gives measurements in fraction (in inch)
Vernier gives measurements up to two decimal places
(in cm)
Vernier gives measurements in fraction (in inch)
Retainer: Used to block movable part to allow the
easy transferring a measurement.
Micrometer:A micrometer sometimes known as a “Micrometer
Screw Gauge”, is a device used widely in mechanical
engineering and machining as well as most mechanical
trades for precision measurement, along with other
metrological instruments such as dial calipers and vernier
calipers. Micrometers are often, but not always, in the form
of calipers.
[35]

36. Types of Micrometer:
Outside Micrometer (aka micrometer caliper),
typically used to measure wires, spheres, shafts and
blocks.
Inside Micrometer, used to measure the diameter of
holes.
Depth Micrometer, measures depths of slot and steps.
Bore Micrometer, typically a three-anvil head on a
micrometer base used to accurately measure inside
diameters.
Tube Micrometer, used to measure the thickness of
tubes.
Dial Indicator:
Dial indicators, also known as dial gauge and probe
indicators, are instruments used to accurately measure small
linear distances, and are frequently used in industrial and
mechanical processes. They are named as so because the
measurement results are displayed in a magnified way by
means of a dial.
Dial Indicator may be used to check the variation in
tolerance during the inspection process of a machined part,
measure the deflection of a beam or ring under laboratory
conditions, as well as many other situations where a small
measurement needs to be registered or indicated. Dial
indicators typically measure ranges from 0.25mm to
300mm (0.015in to 12.0in), with graduations of 0.001mm
to 0.01mm (metric) or 0.00005in to 0.001in (imperical).
[36]

37. GPM ASSEMBLY & CNC ASSEMBLY
GPM Section:GPM stands for general purpose machines.These are
generally manually worked machines involving no
computerized or numerical control. These machines are
semiautomatic in nature and some of its operation like table
movement, job movement, tool movement etc. can be
carried out either automatically or even manually. These are
operated by concerned operations only. The concept of
modern days machines originated from GPMs itself. These
are the simplest from of the metal working machines.
Examples of these machines- Lathe machines, milling
machines, drilling machines, grinding machines etc.
In HMT, Pinjore unit primarly four types of GPM are
manufactured1. FN2 milling machines
2. FN3 milling machines
3. Turret Ram milling machines
4. Broaching machines.
The machines are further classified into horizontal,
vertical and universal milling machines.
a) When the rotating spindle lies vertical w.r.t. the table the
machine is termed as vertical (V) milling machine.
[37]

38. b) When the rotating spindle lies horizontal w.r.t. the table the
machine is as horizontal (H) milling machine.
c) When the cutting can be done at any angle of the job with the
help of rotary motion of tile table the machine is termed as
universal (U) milling machine.
Thus, these machines are named as FN2V, FN2H, FN2U,
FN3H, FN3V, FN3U, TRM3V, and TRM3H.Now here we
would discuss the features of the three types of milling
machines with their properties:-
Swivel is contained only in universal milling machine, since the
table can turn at different angles with its help.
[38]

39. Assembly of Milling Machines:1) First of all the parts are obtained from the foundary and
machined accordingly to give the desired shape to them.
2) The base is leveled properly with proper instruments .
3) Then the column is aligned w.r.t. the base. The column is
attached to the base with the help of guide pins which form a
right fit and later with the help of screws.
4) The knee is then aligned with the base keeping in mind that
the face of the saddle is parallel with the base.
5) Then the saddle is mounted on the knee and aligned properly.
6) The table is then mounted on the saddle with the help of
guides which form a proper fixture with each other.
7) The ball screw is then attached which is responsible for the
vertical movement.
8) The gears and the pulleys are then assembled inside the
column along with other basic components.
9) The electrical assembly is carried out with proper earthing
facility.
10) Then all the accessories are attached to it.
11) Final inspection is done and machine is dispatched.
[39]

40. BROACHING MACHINE :A broach is a multi- point cutting tool consisting of a bar
having a surface containing a series of cutting teeth or edges
which gradually increases in size from starting and to the rear
end. The basic purpose of the machine is to form splines to
hollow jobs. Splines are multiple slots on the hollow surface of
the job. The surface may be flat, circular, or any intricate shape.
In broaching , the broach is pushed or pulled over/through a
surface of workpiece. Each tooth of the tool takes a slice from the
surface. Broaching of inside surface is called internal or hole
broaching and that of outside surface is called surface broaching.
Material:High speed steel, brazed carbides or disposable inserts are
sometimes used for cutting edges for machining of cast iron parts.
Carbide tools are used to an advantage on steel.
HMT manufacturers two types of broaching machine:a) Vertical Broaching Machines.
b) Horizontal Broaching Machines.
Reconditioning of Machine (RCM):This section is concerned with the reconditioning of machine
i.e. repair and maintenance of the worn out or faulty mahines.
First of ll the defect is detected and then worked upon
accordingly. If the fault is of small scale then it is dealt here itself
or sent for re-machining or as scrap in the foundary.
[40]

41. CNC SECTION
Introduction
We know that GPMs are semi - automatic machines. They
require an operator for each work piece loaded on machine and in
a limited period. Mass production is not possible in these
machines. Moreover complex shaped jobs require high precision.
They need for flexible automation has always been felt. And this
is an era of machine tool automation. So, flexible automation is
implemented in machine tools in the form of NC and CNC
(Computerized Numerical Control) technology . Today HMT is
producing a lot of CNC variants of conventional machine tools
with the specialized functions and mostly CNC products.
CNC machines are part of the field named mechatronics. This
field is the combination of electronics and mechanical
engineering fields. When they work in combination they are
termed as above. A single CNC machine can perform variety of
machining operations in a sequential order (based upon the
programme). For example drilling , tapping , slotting, milling, etc.
operator is used only for clamping and declamping purpose ( after
feeding the programme ). These machines ensure repeatability of
the dimensions (precision). Accuracy of these machines is in
microns.
A CNC machine may be of three dimensional coordinate system
with XYZ axis. Rest two are available on machines whose table
can rotate and tilt. These are 4th and 5th axis. The axis of the
spindle is termed as Z axis. The axis which crosses Z axis
[41]

42. perpendicularly is X axis and the other mutually perpendicular
axis is Y axis. CNC machines differ in orientation of the main
spindle. If spindle is horizontal it is termed as HMC (horizontal
machining centre) and if the spindle is vertical it is termed as
VMC (vertical machining centre). Model number of machine
depends upon capacity of machine. Capacity means traverse
length along various axis or maximum size of the pallet. Thus a
VTC 1000 designates a CNC machines whose spindle is vertical
with pallet size or traverse length of 1000mm.
Various CNCs produced here:- HMC 320M, HMC 400M,
HMC 500M, HMC 600M, HMC 800M, VMC 400M, VMC
500M, VMC 800M, VMC 1000M etc.
Assembly:Main parts of the CNC machine are:1. Bed
2. Column
3. Saddle
4. Table
5. Pallet chaner (optional)
6. Magazine
7. AC servo motors
8. Tool changer arm
9. Head
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43. 10. Main spindle
The different processes of assembly are:1. Procurement of various parts.
2. Bed is leveled.
3. Column is fixed on bed.
4. Ball screws and drive motors are installed.
5. Alignment of column w.r.t. bed.
6. Fixing table on saddle.
7. Installing ball screws and drive motor.
8. Alignment of saddle w.r.t. column.
9. Fixing table on saddle.
10. Laser test:- In this test the laser beam
pairs of prism one attached to the table
spindle of the machine and reflected back
part and data is collected on the computer
corrected.
is thrown on the
and other on the
through the same
and thus can be
11. Tool magazine is assembled and attached to the machine.
12. The oiling system is attached to the machine as separate
apparatus and solves the purpose of lubrication .
13. All electrical and electronics appliances are installed.
14. The body of the machine is and rest of the accessories are
attached to it.
15. Final inspection is done.
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44. Machine Description:Salient features of CNC machines are as follows:1) Bed type machine configuration:Bed type construction with longitudinal and cross movement
to work table and vertical movement to head , provides stable
cutting condition and maximum rigidity. Box type construction of
bed and column with properly ribbed reinforcement minimizes
torsion and flexural deflection.
2) Linear motion with guide ways:Preloaded anti - friction linear motion type. Guide ways in the
entire three provide clearance free guidance for slides during
cutting. Their use significantly reduces the coefficient of friction
and eliminates stick slip and thermal generation during high speed
positioning. In addition they offer high positioning and
outstanding contouring capability.
3) One package design:One package design i.e. integral mechanical- electrical
construction with CNC unit mounted on machine guarding,
substantially cuts down floor space requirements. This enhances
productivity per unit area and assures easy machine movement
when production line is changed.
4) Long nose quill type spindle:[44]

45. Cylindrically shaped head end and prevents any interference
with the work complicated shape. This configuration also
eliminates interference even with large steep work. Machining of
deep holes in the work are also possible with full power and
without compromising tool rigidity.
5) Spindle cooling( for machine with spindle speed of 6000
rpm):Circulation of cooled oil through the oil jacket around the
main spindle bearing, maintains precision even in long and
continuous runs.
6) Stepless AC spindle motor:AC spindle motor eliminates the troublesome brush inspections
and replacements required in case of DC motors. Another
advantage of DC motor is that it reduces electricaly consumption.
7) Electronic spindle orientation:The spindle motor has build in encoder for position feedback of
the spindle. Spindle orientation stops spindle in a particular
position. This helps in retracting bars without damaging bores in
boring operations and counter-boring/Facing. Automatic tool
change is also achieved through the features.
8) AC servomotors:All the three axes are driven through AC servomotors. Their
[45]

46. use provides a higher rapid rate of revolution with minimum
maintenance. They also provide high acceleration and
deceleration property and subsequently increase the machining
efficiency.
9) Lubrication:Automatic lubrication is provided for minimal operator
attention. Main spindle bearing and all axes drive bearing are
fitted with synthetic grease, requiring no attention for long
periods . All axes ball screws and linear re-circulating bearings
are also lubricated.
10) Automatic chip collection:Flushing coolant with discharge of 100lpm is used for
automatic flushing of chips and is collected in tray at rear of
machine. Wide channels with sufficient scope are provided in
both sides of bed for easy disposal of chips at rear of machine.
11) Guide protection:Guide ways protection with telescopic cover protects guide
ways against external damages and chips.
12) Automatic Tool Changer(ATC):Machine is equipped with a suitable number of tool
[46]

47. station/pocket (mainly12,30,60,120) . Using cam the automatic
tool changer changes a tool accurately and swiftly.
13)Numeric head counter balance:It offsets the natural weight of spindle head and guarantees
consistent cutting , high speed and highly accurate positioning . It
eliminates head falling.
Machining Features (Optional):1. External coolant on spindle:- External coolant facilities
the machining of steel/aluminium. It also helps in taking away
chips from machining zone with its large flow.
2. Mist coolant:- Machining of light metals is faciliated with
mist coolant. Mist coolant takes away heat from work zone, with
change of state. It does not require any return path.
3. Chip conveyor:- It takes away large volume of chips
produced out of the machine continuously with its independent
drive.
4. Refrigeration type of spindle coolant:- Coolant of cooled
oil with heat exchanger(refrigeration type), through spindle jacket
provides higher spindle stability which results in improved
working accuracy.
5. Spindle mounted probe:- Spindle mounted probe with auto
measuring cycle and datum cycle makes fixture/job setting
simple.
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48. 6. Higher speed spindle upto 8000 rpm :- It facilitates
machining of light metals with latest tool technology.
7. Pallet changer:- This part is concerned with handling of
additional table on which the next job can be mounted for
machining meanwhile machining of the current job is going on
which considerably reduces the mounting time.
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