module 2 ppt

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MODULE – 2
DEPARTMENT OF
MECHANICAL ENGINEERING
www.cambridge.edu.in
• MACHINE TOOL OPERATION
• INTRODUCTION TO ADVANCED MANUFACTURING
SYSTEMS:

2.  Machine Tool Operations: Working Principle of lathe, Lathe operations: Turning, facing,
knurling.
 Drilling Machine, drilling operations: Working principles of drilling, boring, reaming.
Working of Milling Machine, Milling: operations: plane milling and slot milling.
 (No sketches of machine tools, sketches to be used only for explaining the operations).
 Introduction to Advanced Manufacturing Systems: Introduction, components of CNC,
advantages and applications of CNC, 3D printing.
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4. Bed: It is the main body of the machine. All main components are bolted on it. It is usually made
by cast iron due to its high compressive strength and high lubrication quality. It is made by
casting process and bolted on floor space.
Tool post : It is bolted on the carriage. It is used to hold the tool at correct position. Tool holder
mounted on it.
Chuck: Chuck is used to hold the workspace. It is bolted on the spindle which rotates the chuck
and work piece. It is four jaw and three jaw according to the requirement of machine.
Head stock : Head stock is the main body parts which are placed at left side of bed. It is serve as
holding device for the gear chain, spindle, driving pulley etc. It is also made by cast iron.
Tail stock : Tail stock situated on bed. It is placed at right hand side of the bed. The main function
of tail stock to support the job when required. It is also used to perform drilling operation.
Lead screw : Lead screw is situated at the bottom side of bed which is used to move the carriage
automatically during thread cutting.
Carriage : It is situated between the head stock and tail stock. It is used to hold and move the tool
post on the bed vertically and horizontally. It slides on the guide ways. Carriage is made by cast
iron.
Apron : It is situated on the carriage. It consist all controlling and moving mechanism of carriage.
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WORKING PRINCIPLE OF LATHE

6. WORKING PRINCIPLE OF LATHE
 lathe: A Lathe machine tool which is used to remove unwanted metals from the work piece to give
desired shape and size. Also known as “centre Lathe”
 Working principle: It operates on the principle of a rotating work piece and a fixed cutting tool. The
lathe is a machine tool. which holds the work piece between two rigid and strong supports called
centers or in a chuck or face plate which revolves. The cutting tool is rigidly held and supported in a
tool post which is fed against the revolving work. The normal cutting operations are performed with
the cutting tool fed either parallel or at right angles to the axis of the work.
 To cut the material properly the tool should be harder than the material of the work piece, should be
rigidly held on the machine and should be fed or progress in a definite way relative to the work.
 Lathe machine is also known as “the mother/father of the entire tool family.
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7. Turning is the most common lathe machining operation. During the
turning process, a cutting tool removes material from the outer diameter
of a rotating work piece In this operation feed is given parallel and depth
of cut is perpendicular to the axis of rotation. The workpiece is fixed
inside the chuck and single point cutting tool is fed against to the
rotating workpiece.
This operation is done to remove the material on the cylindrical surface
to reduce the diameter of the workpiece.
Feed: parallel to axis of rotating work piece
Depth of cut : perpendicular to axis of rotating work piece
1.Turning
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8. 2. Facing
Facing is done on the lathe uses a facing tool to cut a flat
surface perpendicular to the work piece's rotational axis. A
facing tool is mounted into a tool holder that rests on the
carriage of the lathe. The tool will then feed perpendicularly
across the part's rotational axis as it spins in the jaws of the
chuck.
This operation is done to remove the material on the face of
the workpiece. This operation will reduce the length of the work
piece.
Feed: perpendicular to axis of rotating work piece
Depth of cut : parallel to axis of rotating work piece
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9. 3. Knurling
In this operation feed is given parallel and depth of cut is
perpendicular to the axis of rotation. The workpiece is fixed
inside the chuck and tool is fed against to the rotating work
piece. This operation is done to impart diamond shaped
engraves in the cylindrical surface o the workpiece.
Ex: Produce rough textured surface For Decorative and/or
Functional Purpose.
Purpose: Products that require gripping, such as hand tools, are
often knurled to improve their performance and usability.
Feed: parallel to axis of rotating work piece
Depth of pattern : perpendicular to axis of rotating work
piece
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10. WORKING PRINCIPLE OF DRILLING MACHINE
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• Drilling is a metal cutting process carried out by a rotating cutting tool to
make circular holes in solid materials. The tool which makes the hole is
called a drill.
• It is generally called as twist drill, Since it has a sharp twisted edges formed
around a cylindrical tool provided with a helical groove along its length to
allow the cut material to escape through the sharp edges of the conical
surfaces ground at the lower end of the rotating twist drill cuts the material by
peeling it circularly layer by layer when forced against a work piece.
• The removed material chips get curled and escapes through the helical
groove provided in the drill. A liquid coolant is generally used while drilling
to remove the heat of friction and obtain a better finish for the hole.

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Figure: Construction and parts of drilling machines

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Base: It is the main body of the machine. All main components are bolted on it. It is usually made by cast iron
due to its high compressive strength and high lubrication quality. It is made by casting process and bolted on
floor space.
Column: It support for rotating the Swivel table and holding the power transmission system.
Swivel Table: It is attached to the column which can hold the machine vice on which the work pieces are
clamped carry out the drilling operation. The Swivel table can move up and down as well as rotate about the
column as axis. This can be done by means of rotational motion and can be locked to the column by means of
locking nut.
Drill Feed Handle: By the rotation of hand-wheel, the spindle moves up and down in the vertical direction in
order to give the necessary amount of feed to the work.
Spindle: It is used to hold the drill. This spindle is connected to motor shaft. Once the motor is switched on the
spindle starts rotating.
Power Transmission system: To control the speed of the tool rotation, power transmission system is used. It
consists of motor, stepped pulley, V-belt, and the Spindle.

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14.  Drilling is the operation of producing a cylindrical hole by removing metal
from the rotating edge of a cutting tool called the drill.
 The centre of the hole is located on the workpiece by drawing two lines at
right angles to each other and then a centre punch is used to produce an
indentation at the centre. The drill point is pressed at this centre point to
produce the required hole.
 The internal surface of the hole so generated by drilling becomes rough
and the hole is always slightly oversize than the drill used due to the
vibration of the spindle and the drill.
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15.  Boring is done on a drilling machine to increase the size of an already drilled hole. When a suitable size drill is
not available, initially a hole is drilled to the nearest size and using a single point cutting tool, the size of the
hole is increased as shown in Fig.
 By lowering the tool while it is continuously rotating, the size of the hole is increased to its entire depth. when
the boring operation is in progress. It will be continued till the lower surface of the work piece.
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16.  Reaming is the process of smoothing the surface of the drilled holes with a
tool called Reamer. A reamer is similar to the twist drill, but has straight
flutes.
 After drilling the hole to a slightly smaller size, the reamer is mounted in
place of twist drill and with the speed reduced to half of that of the drilling,
reaming is done in the same way as drilling to get surface finished hole.
 It removes only a small amount of material and produces a smooth finish on
the drilled surfaces.
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17. Definition:- A machine tool used for removing the undesirable material from a
workpiece by feeding the workpiece against a rotating multipoint cutting tool
called Milling Cutter.
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18. Working Principle of Milling Process:
• The work piece is held on a worktable of the machine. The
table movement controls the feed of the work piece against the
rotating cutter. This cutter is fixed on a spindle or arbor which
revolves at desired speed. the work piece moves against the
cutter and remove the metal from the surface in order to
produce the desired shape. Work piece is fed against the
rotating milling cutter by moving in X,Y and Z directions.
• Milling cutter is made up of material harder than the
workpiece.
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19. Horizontal Milling Machine
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20. Vertical Milling Machine
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Up milling: In this method, the work piece mounted on the table is fed against the
direction of rotation of the milling cutter. The cutting force is minimum during the
beginning of the cut and maximum at the end of cut. The thickness of chip is more at
the end of the cut. As the cutting force is directed upwards, it tends to lift the workpiece
from the fixtures. A difficulty is felt in pouring coolant on the cutting edge. Due to these
reasons the quality of the surface obtained by this method is wavy. This processes
being safer is commonly used and sometimes called conventional milling.
Down milling: The work piece mounted on the table is moved in the same direction
as that of the rotation of the milling cutter. The cutting force is maximum at the
beginning and minimum at the end of cut. The chip thickness is more at the
beginning of the cut. The work piece is not disturbed because of the bite of the cutter
on the work. The coolant directly reaches to the cutting point. So the quality of
surface finish obtained is high. Because of the backlash error between the feed
screw of the table and the nut, vibration is setup on the work piece.

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1. Plain Milling Operation
2. Face Milling Operation
3. Side Milling Operation
4. Straddle Milling Operation
5. Angular Milling Operation
6. Gang Milling Operation
7. Form Milling Operation
8. Profile Milling Operation
9. End Milling Operation
10.Saw Milling Operation
11.Milling Keyways, Grooves and Slot
12.Gear Milling
13.Helical Milling
14.Cam Milling
15.Thread Milling

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The slab milling is the operation of producing flat, horizontal surface parallel to the axis of rotation of a slab-
milling cutter. The operation is also known as slab milling.
Slab milling is done to remove the material from the upper surface of the mounted heavy work piece. The slab
milling cutters is held in the arbor and it may have straight or helical teethes. Both cutters can be used to
generate flat surfaces. The require depth of cut can be adjusted by raising the table or the knee and the feed is
given by moving the saddle.
Plain Milling
Plain milling: the process of
milling flat surface with the axis of
cutting tool parallel to the surface
being machined.

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• Slot milling is the operation of producing slots like T-slots, plain slots, dovetail slots etc., in worktable fixtures
and other work holding devices. The operation may be performed using lighter end milling cutter, T-slot cutter,
dovetail cutter or side milling cutter. The type of cutter selected depends on the shape of the slot to be
produced. short or long, closed or open, straight or non-straight, deep or shallow, wide or narrow.
• There are different types of slot milling cutters, selected depending on the shape, size, and width of the slots they
are able to produce. Both a face milling cutter and end mills are capable to handle the job.
• Slot milling cutters are extremely versatile tools that have multiple teeth mounted in a circular pattern on a
spindle. They are used to machine solid-jaw mandrels, guide bars, and flat parts from metal stock.
Slot Milling

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T-slots. :The milling operation in which a T-slot milling tool creates a wider
bottom groove in an existing groove. T-slot milling tool is also called woodruff
cutter. Two separate milling cutters are required for milling T-slots. Initially a
side cutter or an end milling cutter is used to cut the throat (open slot) starting
from one end of the work piece to its other end. A T-slot milling cutter is then
used to cut the headspace to the desired dimensions
T-slots are machined according to the following working steps:
- recessing of a rectangular groove
- cutting of a horizontal recess
- cutting of the opposite horizontal recess
Dovetail slot : Similar procedure is followed for cutting a dovetail slot, but a
dovetail slot cutter is used in place of T-slot cutter.
Dovetail grooves are machined in the following working steps:
- recessing of a rectangular groove
- machining of an inclined surface
- machining of the opposite surface
PURPOSE: Slots that allows pieces to interlock and secure in place without the
need to weld or attach joints using other methods

26. INTRODUCTION-
BENEFITS:
 Traditional manufacturing is based on the use of dedicated plant and production lines with little or no flexibility.
 Advanced manufacturing involves versatile production methods that fully utilise capital plant and are more efficient,
effective and responsive.
 Although there are circumstances where traditional, dedicated methods are still appropriate - such as long,
predictable production runs advanced manufacturing has the capacity to accommodate the varying production
requirements and mass customization commonly encountered by industry, without the need for excessive capital
investment.
 The technologies involved in advanced manufacturing can be divided into three main groupings: efficient
production, intelligent production and effective organization.
 Conventionally, an operator decides and adjusts various machines parameters like feed , depth of cut and speed etc
depending on type of job , and controls the slide movements by hand. In a CNC Machine functions parameters
variation (feed, depth of cut and speed) and slide movements are controlled by motors using computer programs.
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Why is CNC Machining necessary?
• To manufacture complex curved geometries in 2D or 3D was extremely expensive by
mechanical means (which usually would require complex jigs to control the cutter
motions)
• Machining components with high Repeatability and Precision
• Unmanned machining operations
• To improve production planning and to increase productivity
• To survive in global market CNC machines are must to achieve close tolerances.

28. What is a CNC ?
CNC : Computer Numerical Control (Computer + Numerical Control) : Computer numerical control (CNC)
is a method for automating control of machine tools through the use of software embedded in a
microcomputer attached to the tool. Numerical control is a programmable automation in which process is
controlled by Numbers, Letters, and symbols.
What is a CNC Machine?
CNC machining is that it is a subtractive manufacturing process that typically employs computerized
controls and machine tools to remove layers of material from a stock piece, known as the blank or work
piece and produces a custom-designed part.
CNC Machining is a process used in the manufacturing sector that involves the use of computers to control
machine tools like lathes, mills and grinders by G and M codes automatically generated by computer
software.
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29. All computer controlled machines are able to accurately and repeatedly control motion in various directions.
Each of these directions of motion is called an axis. Depending on the machine type there are commonly two to
five axes.Additionally, a CNC axis may be either a linear axis in which movement is in a straight line, or a rotary
axis with motion following a circular path.
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30. Fig:- Components of CNC 30

31. (i) Input Devices: These are the devices which are used to input the part program in the CNC
machine. There are different input devices used and these are punch tape reader, magnetic tape
reader, floppy drive, USB Flash Drive etc.
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32. (ii) Machine Control Unit (MCU): It is the heart of the CNC machine. It performs all the
controlling action of the CNC machine, the various functions performed by the MCU are:
 It reads the coded instructions fed into it.
 It decodes the coded instruction.
 It implements interpolation (linear, circular and helical ) to generate axis motion
commands.
It feeds the axis motion commands to the amplifier circuits for driving the axis
mechanisms.
It receives the feedback signals of position and speed for each drive axis.
It implements the auxiliary control functions such as coolant or spindle on/off and tool
change.
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33. (iii) Machine Tool: A CNC machine tool always has a slide table and a spindle to control of
the position and speed. The machine table is controlled in X and Y axis direction and the
spindle is controlled in the Z axis direction.
(iv) Driving System: The driving system of a CNC machine consists of
1. amplifier circuits,
2. drive motors (servo motors, stepper motors)
3. ball lead screw (recirculating ball screw, planetary roller screws, recirculating roller
screw) The MCU feeds the signals (i.e. of position and speed) of each axis to the amplifier
circuits. The control signals are than augmented (increased) to actuate the drive motors.
And the actuated drive motors rotate the ball lead screw to position the machine table.
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35. (v) Feedback System: This system consists of transducers that acts like sensors. It is also called as measuring
system. It contains position and speed transducers that continuously monitor the position and speed of the
cutting tool located at any instant. The MCU receives the signals from these transducers and it uses the
difference between the reference signals and feedback signals to generate the control signals for correcting the
position and speed errors.
(vi) Display Unit: A monitor is used to display the programs, commands and other useful
data of CNC machine.
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36. Advantages:
• High Repeatability, Accurate and Precision
• Volume of production is very high
• Very efficient in producing Complex contours/surfaces with high reliability and precision.
• Flexibility in job change, automatic tool settings, that enables less scrap and will reduce
idle time in production leads to high productivity.
• Quick response to the change in design that gives edge in the market.
• Product life cycle can be reduced.
• More safe, higher productivity and better quality
• Less paper work, faster prototype production, reduction in lead times
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37. Disadvantages:
• Initial investment is high
• Skilled and trained operators is required to setup operation
• Computers and programming knowledge required
• Maintenance is difficult.
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38. • CNC machining is a manufacturing process used in a variety of industries, including automotive,
aerospace, construction, and agriculture.
• CNC machining processes are suitable for a variety of engineering materials, including metals (such as
aluminum, brass, stainless steel, alloy steel, etc.), plastics (such as PEEK, PTFE, nylon, etc.), wood, foam,
composite materials, etc.
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39. Typical manufacturing techniques are known as ‘Subtractive Manufacturing’ because the process is one of
removing material from a preformed block. Processes such as Milling and Cutting are subtractive manufacturing
techniques. This type of process creates a lot of waste since; the material that is cut off generally cannot be used
for anything else and is simply sent out as scrap.
What is 3D Printing?
Additive manufacturing or 3D printing (commonly called) is a process that creates a physical object from a
digital design. There are different 3D printing technologies and materials you can print with, but all are based on
the same principle: a digital model is turned into a solid three-dimensional physical object by adding material
layer by layer 3D printing enables you to produce complex shapes using less material than traditional
manufacturing methods.
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41.  DESIGN OR MODELING IN CAD: In order to produce a 3D object first have to have its virtual design.
This 3D modeling software like Blender, Sketch Up, Auto Cad, Solid Works, Maya, Photo Shop, Thinker
Cad or others to create your own designs. SCAN is Another way to create a three-dimensional digital file is
through 3D scanning.
 GENERATING AN STL OR 3MF FILE: Once the CAD file is developed, the next thing one has to
consider is converting it into specific file formats. The file formats are specified based on the technology of
printing being employed by that particular 3D printer. (standard tessellation language)
 SLICING: This is the process of translating the 3D File into instructions for the 3D printer to follow. Slicing
is dividing or chopping the 3D model into hundreds or thousands of horizontal layers, telling the machine
exactly what to do, step by step. After the files are Sliced, a new file format is generated called G-code, G-
code contains printer commands, so what slicing does is, it takes the STL file’s geometry data and creates a
list of instructions the printer must follow to print the model. G-code is the most widely used numerical
code programming language,
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42.  PRINTING: The printing machines are made of many moving and intricate parts, and they demand correct
maintenance and calibration to produce successful prints. Most 3D Printers do not need to be monitored
after the printing has begun. The machine will follow the automated G-code instructions, so as long as
there is no software error or the machine doesn’t run out of raw material, there should not be a issues
during the printing process. the removal of a part is a technical process that requires professional skills and
specialized equipment within a controlled environment.
 POST-PROCESSING: Post-processing is an important step for the aesthetic and function of the parts, In
the majority of cases 3D printed parts are rough and do not have finished feel but can be vastly improved
with the right techniques and craftsmanship. Through sanding, painting, polishing, and other post-
processing methods, printed parts can accurately become a real-world model of the initial concept.
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Types of 3D Printing Technologies
1. Fused deposition modeling (FDM)
2. Stereolithography (SLA)
3. DLP 3D printing
4. Photopolymer Phase Change Inkjets (PolyJet)
5. Selective laser sintering (SLS) – Direct metal laser sintering (DMLS)
6. Plaster-based 3D printing (PP) – Powder bed and inkjet head 3D printing
7. Thermal Phase Change Inkjets
8. Laminated object manufacturing (LOM)

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Fused Deposition Modeling:
is an additive manufacturing technology commonly used for modeling,
prototyping, and production applications. FDM works on an "additive"
principle by laying down material in layers. A plastic filament or metal
wire is unwound from a coil and supplies material to an extrusion nozzle
which can turn the flow on and off. The nozzle is heated to melt the
material and can be moved in both horizontal and vertical directions by a
numerically controlled mechanism, directly controlled by a computer-
aided manufacturing (CAM) software package. The model or part is
produced by extruding small beads of thermoplastic material to form
layers as the material hardens immediately after extrusion from the nozzle.
Stepper motors or servo motors are typically employed to move the
extrusion head.

45.  FLEXIBILITY:
Another big advantage of 3D printing is that any given printer can create almost anything that fits within its build volume.
With traditional manufacturing processes, each new part or change in part design, requires a new tool, mold, die, or jig to be
manufactured to create the new part.
 RAPID PROTOTYPING
3D printing can manufacture parts within hours, which speeds up the prototyping process. This allows for each stage to
complete faster. When compared to machining prototypes, 3D printing is inexpensive and quicker at creating parts as the part
can be finished in hours.
 PRINT ON DEMAND
Print on demand is another advantage as it doesn’t need a lot of space to stock inventory, unlike traditional manufacturing
processes. This saves space and costs as there is no need to print in bulk unless required.
 STRONG LIGHTWEIGHT PARTS
The main 3D printing material used is plastic, although some metals also can be used for 3D printing. However, plastics offer
advantages as they're lighter than their metal equivalents.
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46.  MINIMIZING WASTE
The production of parts only requires the materials needed for the part itself, with little or no wastage as compared to
alternative methods which are cut from large chunks of non-recyclable materials.
 COST EFFECTIVE
As a single step manufacturing process, 3D printing saves time and therefore costs associated with using different
machines for manufacture. 3D printers can also be set up and left to get on with the job, meaning that there is no need
for operators to be present the entire time.
 ENVIRONMENTALLY FRIENDLY
As this technology reduces the amount of material wastage used this process is inherently environmentally friendly.
 ADVANCED HEALTHCARE
3D printing is being used in the medical sector to help save lives by printing organs for the human body such as livers,
kidneys and hearts.
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47.  LIMITED MATERIALS
While 3D Printing can create items in a selection of plastics and metals the available selection of raw materials is not
exhaustive. This is due to the fact that not all metals or plastics can be temperature controlled enough to allow 3D
printing.
 RESTRICTED BUILD SIZE
3D printers currently have small print chambers which restrict the size of parts that can be printed. Anything bigger will
need to be printed in separate parts and joined together after production. This can increase costs and time for larger parts
due to the printer needing to print more parts before manual labour is used to join the parts together.
 POST PROCESSING
Although large parts require post-processing, as mentioned above, most 3D printed parts need some form of cleaning up
to remove support material from the build and to smooth the surface to achieve the required finish. Post processing
methods used include water jetting, sanding, a chemical soak and rinse, air or heat drying, assembly and others.
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48.  LARGE VOLUMES
3D printing is a static cost unlike more conventional techniques like injection moulding, where large volumes may be
more cost effective to produce. While the initial investment for 3D printing may be lower than other manufacturing
methods, once scaled up to produce large volumes for mass production, the cost per unit does not reduce as same as
with injection moulding.
PART STRUCTURE
With 3D printing (also referred to as Additive Manufacturing) parts are produced layer-by-layer. Although these
layers adhere together it also means they will delaminate under certain stresses or orientations.
 REDUCTION IN MANUFACTURING JOBS
Another of the disadvantages of 3D technology is the potential reduction in human labour, since most of the
assembly is automated and done by printers.
 COPYRIGHT ISSUES
As 3D printing is becoming more popular and accessible there's a greater possibility for people to make fake and
counterfeit products and it'll almost be impossible to inform the difference. This has evident issues around copyright
also as for internal control 48

49. Applications of 3D Printing
 Consumer Products (Eyewear, Footwear, Design, Furniture)
 Industrial Products (Manufacturing Tools, Prototypes, Functional End-use Parts)
 Architectural Scale Models & Maquettes
 Prototyping
 Specialized Parts – Aerospace, Military, Biomedical Engineering, Dental
 Hobbies And Home Use
 Future Applications– Medical (Body Parts), Buildings And Cars
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