This presentation contains various aspects of metal cutting like mechanics of chip formation, single point cutting tool, chip breakers, types of chips,etc
This presentation contains various aspects of metal cutting like mechanics of chip formation, single point cutting tool, chip breakers, types of chips,etc
Fundamentals of Metal cutting and Machining Processes
MACHINING OPERATIONS AND MACHINING TOOLS
Turning and Related Operations
Drilling and Related Operations
Milling
Machining Centers and Turning Centers
Other Machining Operations
High Speed Machining
Theory of Metal cutting - Principles of Metal cutting, orthogonal and oblique cutting, Merchant circle diagram, cutting forces, power requirements, Economics of machining,problems
This chapter aims to provide basic backgrounds of different types of machining processes and highlights on an understanding of important parameters which affects machining of metals with their chip removals.
Metal cutting or Machining is the process of producing workpiece by removing unwanted material from a block of metal. in the form of chips. This process is most important since almost all the products get their final shape and size by metal removal. either directly or indirectly.
The major drawback of the process is loss of material in the form of chips. In this chapter. we shall have a fundamental understanding of the basic metal process.
Introduction Hot Working and Cold Working of Metals Forging Processes- Open, impression die forging, Closed die forging-forging operation Rolling of metals-types of rolling- Flat strip rolling-shape rolling operation -Defects in rolled parts- Principle of rod and wire drawing-tube drawing -Principle of extrusion Types-hot and cold extrusion.
High-frequency welding is included in a group of resistance welding process variations that use high-frequency welding current (1kHz to 800kHz) to concentrate the welding heat at the desired location.
The heat produces the coalescence of metals, and an upsetting force usually is applied to produce a forged weld.
High-frequency resistance welding is an automated process and is not adaptable to manual welding.
High-frequency resistance welding was developed during the late 1940s and early 1950s to fill the need for high-integrity butt joints and seam welds in pipe and tubing.
But today the process is also used in the manufacture of products such as spiral-fin boiler tubes, closed roll form shapes, and welded structural beams.
A wide range of commonly used metals can be welded, including low-carbon and alloy steels, ferritic and austenitic stainless steels, and many aluminum, copper, titanium, and nickel alloys.
HFW is based on two main electrical phenomena
Skin effect
Proximity effect
Please refer this file just as reference material. More concentration should on class room work and text book methodology.
Thermal aspects of Machining, Tool materials, Tool wear Cutting fluids and Machinability.
This slide is all about Metal cutting and Machining tools insights. It covers Mechanics of metal cutting, orthogonal and oblique machining, Tools geometry, Types of Chips, and Tools Signature.
this is 2nd presentation of manufacturing processes in this presentation we discuss in detail about the theory of metal cutting, machiening processes,cutters etc
Fundamentals of Metal cutting and Machining Processes
MACHINING OPERATIONS AND MACHINING TOOLS
Turning and Related Operations
Drilling and Related Operations
Milling
Machining Centers and Turning Centers
Other Machining Operations
High Speed Machining
Theory of Metal cutting - Principles of Metal cutting, orthogonal and oblique cutting, Merchant circle diagram, cutting forces, power requirements, Economics of machining,problems
This chapter aims to provide basic backgrounds of different types of machining processes and highlights on an understanding of important parameters which affects machining of metals with their chip removals.
Metal cutting or Machining is the process of producing workpiece by removing unwanted material from a block of metal. in the form of chips. This process is most important since almost all the products get their final shape and size by metal removal. either directly or indirectly.
The major drawback of the process is loss of material in the form of chips. In this chapter. we shall have a fundamental understanding of the basic metal process.
Introduction Hot Working and Cold Working of Metals Forging Processes- Open, impression die forging, Closed die forging-forging operation Rolling of metals-types of rolling- Flat strip rolling-shape rolling operation -Defects in rolled parts- Principle of rod and wire drawing-tube drawing -Principle of extrusion Types-hot and cold extrusion.
High-frequency welding is included in a group of resistance welding process variations that use high-frequency welding current (1kHz to 800kHz) to concentrate the welding heat at the desired location.
The heat produces the coalescence of metals, and an upsetting force usually is applied to produce a forged weld.
High-frequency resistance welding is an automated process and is not adaptable to manual welding.
High-frequency resistance welding was developed during the late 1940s and early 1950s to fill the need for high-integrity butt joints and seam welds in pipe and tubing.
But today the process is also used in the manufacture of products such as spiral-fin boiler tubes, closed roll form shapes, and welded structural beams.
A wide range of commonly used metals can be welded, including low-carbon and alloy steels, ferritic and austenitic stainless steels, and many aluminum, copper, titanium, and nickel alloys.
HFW is based on two main electrical phenomena
Skin effect
Proximity effect
Please refer this file just as reference material. More concentration should on class room work and text book methodology.
Thermal aspects of Machining, Tool materials, Tool wear Cutting fluids and Machinability.
This slide is all about Metal cutting and Machining tools insights. It covers Mechanics of metal cutting, orthogonal and oblique machining, Tools geometry, Types of Chips, and Tools Signature.
this is 2nd presentation of manufacturing processes in this presentation we discuss in detail about the theory of metal cutting, machiening processes,cutters etc
Merchant circle merchant confidence index survey resultsMerchantCircle
New marketing trends data from MerchantCircle's 6th quarterly survey of small business owners across the U.S. reveals that Facebook Ads are gaining popularity among small businesses and provides new insights into the group deals market, including increased pressure on Groupon and LivingSocial from Facebook Deals and Google Offers.
Slides accompanying 2.008x* video module on Machining, Prof. John Hart, MIT, 2016.
*Fundamentals of Manufacturing Processes on edX: https://www.edx.org/course/fundamentals-manufacturing-processes-mitx-2-008x
Theory of metal cutting MG University(S8 Production Notes)Denny John
Theory of metal cutting MG University(S8 Production Notes)
Scenario of manufacturing process – Deformation of metals,
Schmid’s law (review only) – Performance and process parameters – single point cutting
tool nomenclature - attributes of each tool nomenclature - attributes of feed and tool
signature on surface roughness obtainable, role of surface roughness on crack initiation -
Oblique and orthogonal cutting – Mechanism of metal removal - Primary and secondary
deformation shear zones - Mechanism of chip formation, card model, types of chip,
curling of chips, flow lines in a chip, BUE, chip breakers, chip thickness ratio –
Mechanism of orthogonal cutting: Thin zone and thick zone, Merchant’s analysis – shear
angle relationship, Lee and Shaffer`s relationship, simple problems – Friction process in
metal cutting: nature of sliding friction, columb`s law, adhesion theory, ploughing, sublayer
flow – Empirical determination of force component.
MACHINING OPERATIONS AND MACHINE TOOLS
Methods of Holding the Work in a Lathe (Chuck,Collet,face Plate,Holding the Work Between Centers)
Work Holding for Drill Presses
Boring Drilling, Reaming, Tapping Milling
Peripheral Milling vs. Face Milling
Shaper and Planer
Broaching
Traditional machining processes involves the machining processes using machine tool like lathe milling, drilling, milling grainding, shaper, planner machines
Classification of metal removal process and machines: Concept of generatrix and directrix Geometry of single point cutting tool and tool angles, tool nomenclature in ASA, ORS, NRS. Concept of orthogonal and oblique cutting, Mechanism of Chip Formation: Type of chips. Mechanics of metal cutting, interrelationships between cutting force, shear angle, strain and strain rate. Various theories of metal cutting, Thermal aspects of machining and measurement of chip tool interface temperature, Friction in metal cutting
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
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Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
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Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
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TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
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The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
METAL MACHINING
1. ISE 316 - Manufacturing
Processes Engineering
Chapter 21
THEORY OF METAL
MACHINING
Overview of Machining Technology
Theory of Chip Formation in Metal
Machining
Force Relationships and the Merchant
Equation
Power and Energy Relationships in
Machining
Cutting Temperature
2. ISE 316 - Manufacturing Processes
Engineering
Material Removal Processes
A family of shaping operations, the common
feature of which is removal of material from a
starting workpart so the remaining part has the
desired shape
Categories:
◦ Machining – material removal by a sharp cutting
tool, e.g., turning, milling, drilling
◦ Abrasive processes – material removal by hard,
abrasive particles, e.g., grinding
◦ Nontraditional processes - various energy forms
other than sharp cutting tool to remove material
3. ISE 316 - Manufacturing Processes
Engineering
Machining
Cutting action involves shear deformation of
work material to form a chip
As chip is removed, a new surface is
exposed
Figure 21.2 - (a) A cross-sectional view of the machining process, (b)
tool with negative rake angle; compare with positive rake angle in (a)
4. ISE 316 - Manufacturing
Processes Engineering
Why Machining is Important
Variety of work materials can be
machined
◦ Most frequently applied to metals
Variety of part shapes and special
geometry features possible, such as:
◦ Screw threads
◦ Accurate round holes
◦ Very straight edges and surfaces
Good dimensional accuracy and
surface finish
5. ISE 316 - Manufacturing
Processes Engineering
Disadvantages with
Machining
Wasteful of material
◦ Chips generated in machining are wasted
material, at least in the unit operation
Time consuming
◦ A machining operation generally takes
more time to shape a given part than
alternative shaping processes, such as
casting, powder metallurgy, or forming
6. ISE 316 - Manufacturing
Processes Engineering
Machining in the Manufacturing
Sequence
Generally performed after other
manufacturing processes, such as
casting, forging, and bar drawing
◦ Other processes create the general shape
of the starting workpart
◦ Machining provides the final shape,
dimensions, finish, and special geometric
details that other processes cannot create
7. ISE 316 - Manufacturing
Processes Engineering
Machining Operations
Most important machining operations:
◦ Turning
◦ Drilling
◦ Milling
Other machining operations:
◦ Shaping and planing
◦ Broaching
◦ Sawing
8. ISE 316 - Manufacturing Processes
Engineering
Turning
Single point cutting tool removes material from a
rotating workpiece to form a cylindrical shape
Figure 21.3 (a) turning
9. ISE 316 - Manufacturing
Processes Engineering
Drilling
Used to create a round hole, usually by means of
a rotating tool (drill bit) that has two cutting
edges
Figure 21.3 - The three most
common types of machining
process: (b) drilling
10. ISE 316 - Manufacturing
Processes Engineering
Milling
Rotating multiple-cutting-edge tool is moved
slowly relative to work to generate plane or
straight surface
Two forms: peripheral milling and face milling
Figure 21.3 - (c) peripheral milling, and (d) face milling
11. ISE 316 - Manufacturing
Processes Engineering
Cutting Tool Classification
1. Single-Point Tools
◦ One cutting edge
◦ Turning uses single point tools
◦ Point is usually rounded to form a nose
radius
2. Multiple Cutting Edge Tools
◦ More than one cutting edge
◦ Motion relative to work usually achieved
by rotating
◦ Drilling and milling use rotating multiple
cutting edge tools.
12. ISE 316 - Manufacturing
Processes Engineering
Figure 21.4 - (a) A single-point tool showing rake face, flank, and tool
point; and (b) a helical milling cutter, representative of tools with
multiple cutting edges
13. ISE 316 - Manufacturing
Processes Engineering
Cutting Conditions in
Machining
The three dimensions of a machining
process:
◦ Cutting speed v – primary motion
◦ Feed f – secondary motion
◦ Depth of cut d – penetration of tool below
original work surface
For certain operations, material removal
rate can be found as
MRR = v f d
where v = cutting speed; f = feed; d = depth of
cut
14. ISE 316 - Manufacturing
Processes Engineering
Cutting Conditions for Turning
Figure 21.5 - Cutting speed, feed, and depth of cut for a turning
operation
15. ISE 316 - Manufacturing
Processes Engineering
Roughing vs. Finishing in
Machining
In production, several roughing cuts are
usually taken on the part, followed by
one or two finishing cuts
Roughing - removes large amounts of
material from the starting workpart
◦ Creates shape close to desired geometry, but
leaves some material for finish cutting
◦ High feeds and depths, low speeds
Finishing - completes part geometry
◦ Achieves final dimensions, tolerances, and
finish
◦ Low feeds and depths, high cutting speeds
16. ISE 316 - Manufacturing
Processes Engineering
Machine Tools
A power-driven machine that performs a
machining operation, including
grinding
Functions in machining:
◦ Holds workpart
◦ Positions tool relative to work
◦ Provides power at speed, feed, and depth
that have been set
The term is also applied to machines
that perform metal forming operations
17. ISE 316 - Manufacturing
Processes Engineering
Orthogonal Cutting Model
A simplified 2-D model of machining that
describes the mechanics of machining fairly
accurately
Figure 21.6 - Orthogonal cutting: (a) as a three-dimensional process
18. ISE 316 - Manufacturing
Processes Engineering
Chip Thickness Ratio
where r = chip thickness ratio; to = thickness of
the chip prior to chip formation; and tc = chip
thickness after separation
Chip thickness after cut is always greater
than before, so chip ratio is always less
than 1.0
c
o
t
t
r
19. ISE 316 - Manufacturing
Processes Engineering
Determining Shear Plane
Angle
Based on the geometric parameters of the
orthogonal model, the shear plane angle
can be determined as:
where r = chip ratio, and = rake angle
sin
cos
tan
r
r
1
20. ISE 316 - Manufacturing Processes
Engineering
Figure 21.7 - Shear strain during chip formation: (a) chip formation
depicted as a series of parallel plates sliding relative to each other,
(b) one of the plates isolated to show shear strain, and (c) shear
strain triangle used to derive strain equation
21. ISE 316 - Manufacturing Processes
Engineering
Shear Strain
Shear strain in machining can be
computed from the following equation,
based on the preceding parallel plate
model:
= tan( - ) + cot
where = shear strain, = shear plane
angle, and = rake angle of cutting tool
22. ISE 316 - Manufacturing
Processes Engineering
Figure 21.8 - More realistic view of chip formation, showing shear
zone rather than shear plane. Also shown is the secondary shear
zone resulting from tool-chip friction
23. ISE 316 - Manufacturing
Processes Engineering
Four Basic Types of Chip in
Machining
1. Discontinuous chip
2. Continuous chip
3. Continuous chip with Built-up Edge
(BUE)
4. Serrated chip
24. ISE 316 - Manufacturing
Processes Engineering
Segmented Chip
Brittle work
materials (e.g., cast
irons)
Low cutting speeds
Large feed and
depth of cut
High tool-chip
friction
Figure 21.9 - Four types of chip
formation in metal cutting:
(a) segmented
25. ISE 316 - Manufacturing
Processes Engineering
Continuous Chip
Ductile work materials
(e.g., low carbon
steel)
High cutting speeds
Small feeds and
depths
Sharp cutting edge on
the tool
Low tool-chip friction
Figure 21.9 - Four types of chip
formation in metal cutting:
(b) continuous
26. ISE 316 - Manufacturing
Processes Engineering
Continuous with BUE
Ductile materials
Low-to-medium cutting
speeds
Tool-chip friction causes
portions of chip to
adhere to rake face
BUE formation is
cyclical; it forms, then
breaks off
Figure 21.9 - Four types of chip
formation in metal cutting: (c)
continuous with built-up edge
27. ISE 316 - Manufacturing
Processes Engineering
Serrated Chip
Semicontinuous -
saw-tooth
appearance
Cyclical chip
formation of
alternating high shear
strain then low shear
strain
Most closely
associated with
difficult-to-machine
metals at high cutting
speeds
Figure 21.9 - Four types of chip
formation in metal cutting: (d)
serrated
28. ISE 316 - Manufacturing
Processes Engineering
Forces Acting on Chip
Friction force F and Normal force to
friction N
Shear force Fs and Normal force to shear
Fn
Figure 21.10 -
Forces in metal
cutting: (a) forces
acting on the chip
in orthogonal
cutting
29. ISE 316 - Manufacturing
Processes Engineering
Resultant Forces
Vector addition of F and N = resultant
R
Vector addition of Fs and Fn =
resultant R'
Forces acting on the chip must be in
balance:
◦ R' must be equal in magnitude to R
◦ R’ must be opposite in direction to R
◦ R’ must be collinear with R
30. ISE 316 - Manufacturing
Processes Engineering
Coefficient of Friction
Coefficient of friction between tool and
chip:
Friction angle related to coefficient of friction as follows:
N
F
tan
31. ISE 316 - Manufacturing
Processes Engineering
Shear Stress
Shear stress acting along the shear
plane:
sin
wt
A o
s
where As = area of the shear plane
Shear stress = shear strength of work material during cutting
s
s
A
F
S
32. ISE 316 - Manufacturing
Processes Engineering
Cutting Force and Thrust Force
Forces F, N, Fs, and Fn cannot be directly
measured
Forces acting on the tool that can be
measured:
◦ Cutting force Fc and Thrust force Ft
Figure 21.10 - Forces
in metal cutting: (b)
forces acting on the
tool that can be
measured
33. ISE 316 - Manufacturing
Processes Engineering
Forces in Metal Cutting
Equations can be derived to relate the
forces that cannot be measured to the
forces that can be measured:
F = Fc sin + Ft cos
N = Fc cos - Ft sin
Fs = Fc cos - Ft sin
Fn = Fc sin + Ft cos
Based on these calculated force,
shear stress and coefficient of friction
can be determined
34. ISE 316 - Manufacturing
Processes Engineering
The Merchant Equation
Of all the possible angles at which shear
deformation could occur, the work material will
select a shear plane angle which minimizes
energy, given by
Derived by Eugene Merchant
Based on orthogonal cutting, but validity
extends to 3-D machining
22
45
35. ISE 316 - Manufacturing
Processes Engineering
What the Merchant Equation
Tells Us
To increase shear plane angle
◦ Increase the rake angle
◦ Reduce the friction angle (or coefficient of
friction)
22
45
36. ISE 316 - Manufacturing
Processes Engineering
Higher shear plane angle means smaller shear
plane which means lower shear force
Result: lower cutting forces, power,
temperature, all of which mean easier
machining
Figure 21.12 - Effect of shear plane angle : (a) higher with a
resulting lower shear plane area; (b) smaller with a corresponding
larger shear plane area. Note that the rake angle is larger in (a), which
tends to increase shear angle according to the Merchant equation
37. ISE 316 - Manufacturing
Processes Engineering
Power and Energy
Relationships
A machining operation requires power
The power to perform machining can be
computed from:
Pc = Fc v
where Pc = cutting power; Fc = cutting
force; and v = cutting speed
38. ISE 316 - Manufacturing
Processes Engineering
Power and Energy
Relationships
In U.S. customary units, power is traditional
expressed as horsepower (dividing ft-lb/min by
33,000)
where HPc = cutting horsepower, hp
00033,
vF
HP c
c
39. ISE 316 - Manufacturing
Processes Engineering
Power and Energy
Relationships
Gross power to operate the machine tool Pg
or HPg is given by
or
where E = mechanical efficiency of machine tool
• Typical E for machine tools = 90%
E
P
P c
g
E
HP
HP c
g
40. ISE 316 - Manufacturing
Processes Engineering
Unit Power in Machining
Useful to convert power into power per unit
volume rate of metal cut
Called the unit power, Pu or unit horsepower,
HPu
or
where MRR = material removal rate
MRR
P
P c
u
MRR
HP
HP c
u
41. ISE 316 - Manufacturing
Processes Engineering
Specific Energy in Machining
Unit power is also known as the specific energy
U
Units for specific energy are typically N-m/mm3 or J/mm3 (in-lb/in3)
wt
F
wvt
vF
MRR
P
PU
o
c
o
cc
u
42. ISE 316 - Manufacturing
Processes Engineering
Cutting Temperature
Approximately 98% of the energy in
machining is converted into heat
This can cause temperatures to be
very high at the tool-chip
The remaining energy (about 2%) is
retained as elastic energy in the chip
43. ISE 316 - Manufacturing
Processes Engineering
Cutting Temperature
Several analytical methods to calculate cutting
temperature
Method by N. Cook derived from dimensional
analysis using experimental data for various work
materials
where T = temperature rise at tool-chip interface; U = specific energy; v
= cutting speed; to = chip thickness before cut; C = volumetric specific
heat of work material; K = thermal diffusivity of the work material
3330
40
.
.
K
vt
C
U
T o
44. ISE 316 - Manufacturing
Processes Engineering
Cutting Temperature
Experimental methods can be used to
measure temperatures in machining
Most frequently used technique is the
tool-chip thermocouple
Using this method, K. Trigger
determined the speed-temperature
relationship to be of the form:
T = K vm
where T = measured tool-chip interface
temperature
45. Metal Cutting theory
Plastically deform a material using a
hard tool in order to obtain desired
physical shape and properties
Very complex phenomena
Essential for high precision; high
performance products