Final report Cơ sở chế tạo máy

BỘ GIÁO DỤC VÀ ĐÀO TẠO
TRƯỜNG ĐẠI HỌC SƯ PHẠM KĨ THUẬT
TP. HỒ CHÍ MINH
..............

MACHINE MANUFACTURING TECHNOLOGY
FUNDAMENTALS OF MACHINE
MANUFACTURING TECHNOLOGY
Final Report
***
PROBLEM 1: HOW CAN YOU SELECT THE OPTIONAL
CUTTING CONDITIONS?
PROBLEM 2: A STUDY ON THE GEOMETRY OF
SINGLE – POINT CUTTING TOOL?
PROBLEM 3: INTRODUCTION TO THE LATHE
MACHINE?
CLASS CODE: FMMT330825E_21_2_02CLC
INSTRUCTORS: TRUONG NGUYEN LUAN VU
PERFORM: NGUYEN DUC NAM
SEMESTER: 2 – YEAR: 2021 – 2022

Tp. Thủ Đức, tháng 6, năm 2022


* Ghi chú:
- Người làm: Nguyễn Đức Nam

SĐT: 0969937878

- MSSV: 20143224
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TP. Thủ Đức, ngày 12 tháng 10 năm 2022
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Table of Contents
List of Figures .......................................................................................................1
Abstract .................................................................................................................2

Research Methodology .........................................................................................2
PROBLEM
1:
How
conditions ? ...................3

can

you

select

the

optional

cutting

Cutting Conditions ................................................................................................3
Selection
of
Conditions ............................................................................4

Cutting

Selecting depth of cup ..................................................................................
6
Selecting feed ...............................................................................................
7
Optimizing cutting speed ..............................................................................7

PROBLEM 2: A study on the geometry of single - point cutting tool ? ..............9
Cutting Tool Geometries ..................................................................................... 9
Single Point Cutting Tool Definition .....................................................................9
Single
Point
Cutting
Geometry ..................................................................10

Tool

PROBLEM 3: Introduction to the lathe machine ? ............................................ 17
Introduction
17

……………………………………………………………………

Lathe Machine Definition ……………………………………………………...
17
Parts of the Lathe Machine and their Functions ………………………………..
19
Work is held in the lathe with a number of methods …………………………..
23
Turning tapers on Engine lathes ………………………………………………..
24
Turret lathes ……………………………………………………………………
25


Single - spindle and Multi - spindle bar machines …………………………….
26

Computer - controlled lathes (CNC lathes) ……………………………………
28
Conclusion ……………………………………………………………………. 30
References
31

…………………………………………………………………….

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List of Figures
Figure 1: To machine a large surface, the tool must be given a
feed……………...4
Figure

2:

Depth

of

cup

and

deep………………………………………………….5
Figure

3:

Cutting

speed…………………………………………………………..5
Figure 4: Example of selection of roughing passes in a turning operation………
5
Figure

5:

Finishing

pass

in

a

turning

operation…………………………………...7
Figure 6: Total cost per part and total time per part versus cutting
speed…………8
Figure 7: Cutting edges, surface and angles on the cutting part of a turning
tool…9
Figure

8:

Tool

geometry

of

a

single

point

cutting

tool…………………………..10
Figure

9:

Single

–

point

Cutting

Tool

Geometry………………………………..11
Figure

10:

Positive

rake

angle…………………………………………………..12
Figure

11:

Negative

rake

angle………………………………………………….13
Figure

12:

The

principal

components

of

an

engine

lathe……………………….19
Figure

13:

Four

work

holding

methods

used

in

lathes…………………………..24
Figure 14: Three methods for turning tapers on an engine lathe……………….25
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Figure

15:

Picture

about

turret

lathes…………………………………………...25
Figure

16:

Single-spindle

and

multi-spindle

bar

machines……………………..26
Figure 17: A close-up view of a single spindle bar machine
Typical parts produced on a single spindle bar machine……………27
Figure 18: The principle components of a six-spindle bar machine
CNC controlled multiple-spindle bar machine………………………
27
Figure 19: Computer-controlled lathes……………..…………………………..28
Figure

20:

CNC

lathes…………………………………………………………..29

Abstract
To test our understanding of the basic subject of machine building technology of
Ho Chi Minh City University of Technology and Education, we need to do a
final report. The instructor gave us 3 main problems to solve: the cutting
conditions, single - point cutting tool and the lathe. Below is the content to solve
the above 3 problems; Includes: definitions, images and machining calculation
formulas. In addition, this final report will be evaluated and corrected.
Research Methodology

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State the concept of definition, analyze and evaluate, compare and contrast.
Using data collection and data analysis methods, look for illustrations to make
the essay more coherent and easy to understand.

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PROBLEM 1: HOW CAN YOU SELECT THE OPTIONAL CUTTING
CONDITIONS
Cutting Conditions
Selecting a cutting Conditions determines the depth of cut, number of feeds,
feed amount, cutting speed and power required under certain machining
conditions.
Reasonable cutting conditions is the cutting mode that takes the least time to
make the product, so it is the cheapest. If the correct tool construction, cutting

geometry parameters, materials, ironing and polishing methods are selected, as
well as the correct setting, clamping of the tool and workpiece, good machine
adjustment and structural technology reasonable will create conditions to choose
a reasonable and beneficial regime.
The cutting conditions is affected by a variety of factors such as the
chemical composition of the material, the manufacturing method of heat
processing, the microstructure, the grain size, and the crystal lattice. The above
factors often influence each other on the cutting mode and cannot be evaluated
independently and separately. The cutting conditions also depends on the
machining method, the type of tool material, the geometrical parameters of the
cutting tool, the mounting conditions, and the clamping of the part, so the
cutting mode is very complicated, often chosen according to experience and use.
Use empirical formulas to calculate the cutting mode.
Each machining operation is characterized by cutting conditions, which
comprises a set of three elements:
-

Cutting velocity V: the traveling velocity of the tool relative to the

workpiece. It is measured in m/s or m/min.
-

Depth of cup d: the axial projection of the length of the active cutting tool

edge, measured in mm. in orthogonal cutting it is equal to the actual width of cut
bD .

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-

Feed f : the ralative movement of the tool in order to process the entire

surface of the workpiece. In orthogonal cutting it is equal to the thickness of cut
h D and is measured in mm t r −1 in turning, or mm/min in milling and drilling.

Figure 1: To machine a large surface, the tool must be given a feed. (Left) In
orthogonal cutting, feed f and depth of cut coincide with the thickness of cut h D and
width of cut b D, respectively. (Right) In oblique cutting, the cutting tool edge is set at
an angle ( tool cutting edge angle ) for easier chip removal.

Selection of Cutting Conditions
For each machining operation, a proper set of cutting conditions must be
selected during the process planning. Decision must be made about all three
elements of cutting conditions:
-

Depth of cut: decided by machining, allowance and shape of the work

piece, power and rigidity of the machine and tool rigidity. The depth of cut is
usually expressed in half stock removal and will never be larger than the main
cutting edge length of the insert.
-

Feed: For the tool holder, “feed rate” is the amount of movement of the tool

holder in one rotation of the work. For the cutter, “feed rate” is expressed by the
value founded by dividing the amount of movement of the machine table in one
rotation of the cutter by the number of teeth (feed per tooth). Lowering “feed

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rate” will extremely shorten tool life. Higher “feed rate” will increase flank
wear.

Figure 2

-

Cutting speed: a term that refers to the speed at which material is removed

with the cutting edge. The amount that the cutting edge moves into the
workpiece is represented as metres (m) per minute. If the RPM is fixed then the
larger the workpiece diameter becomes the higher the cutting speed.

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Figure 3

There are two types of machining operations:
-

Roughing operations: the primary objective of any roughing operation is to

remove as much as possible material from the workpiece for as short as possible
machining time. In roughing operation, quality of machining is of a minor
concern.

-

Finishing operations: the purpose of a finishing operation is to achieve the

final shape, dimensional precision, and surface finish of the machined part.
Here, the quality is of major importance.
Selection of cutting conditions is made with respect to the type of machining
operation. Cutting conditions should be decided in the order depth of cut – feed
– cutting speed
Selecting Depth of Cut
Depth of cut is predetermined by workpiece geometry and final part shape.
In roughing operations, depth of cut is made as large as possible (max depths are
in the range of 6~10mm) with respect to available machine tool, cutting tool
strength, and other factors. Often, a series of roughing passes is required.

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Roughing operations must leave a thin layer of material (~0.5 mm on a side)
required for the subsequent finishing operation.

Figure 4

In the finishing cut, depth is set to achieve the final dimensions with a single
pass removing the excessive material left after roughing.

Figure 5

Selecting Feed
In roughing operations, feed is made as large as possible to maximize metal

removal rate. Upper limits on feed are imposed by cutting forces and setup
rigidity. Feeds in roughing can be as big as 0.5 mm t r −1. If the operation is
finishing, feed should be small to ensure good surface finish. Typical feeds in
finishing are in the range of 0.05~0.15 mm t r −1.
Optimizing cutting speed

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As with most engineering problems, in machining we want to minimize costs,
while increasing productivity. Effciency is the key term - it suggests that good
quality parts are produced at reasonable cost and at high production rate.
Unfortunately, it is almost impossible to combine these contradictable
requirements - cutting at high speed increases productivity but reduces tool life,
therefore increases the production cost as more cutting tools will be necessary
finish the job. Hence, the optimal cutting speed has to be calculated for two
objectives:
- cutting speed for maximum production rate, V max , and
- cutting speed for minimum unit cost, V min .
Both objectives seek to achieve a balance between material removal rate and
tool life.
-

Maximizing production rate: Fox maximum production rate, the speed that

minimizes machining time per unit part is determined. Minimizing cutting time
is equivalent to maximizing productivity. It can be shown, that the cutting time
for one part T c is minimized at a certain value of cutting speed denoted as V max .
-

Minimizing cost per unit: For minimum cost per unit, the cutting speed that

minimizes production cost per part is determined. Again, the total cost of
producing one part is minimized at a value of cutting speed denoted as Vmin. In
all cases, V max is always greater than V min . Since it is diffcult to precisely
calculate either values, a general recommendation is to operate within these two
values, an interval known as the high-efficiency range:

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Figure 6

PROBLEM 2: A STUDY ON THE GEOMETRY OF SINGLE – POINT
CUTTING TOOL?
Cutting Tool Geometries
Cutting tools for metal cutting have many shapes, each of which are described
by their angles or geometries. Every one of these tool shapes have a specific
purpose in metal cutting. The primary machining goal is to achieve the most
efficient separation of chips from the workpiece. For this reason, the selection of
the right cutting tool geometry is critical. Other chip formation influences
include:
- The workpiece material
- The cutting tool material
- The power and speed of the machine
- Various process conditions, such as heat and vibration
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Figure 7

Single Point Cutting Tool Definition
This tool consists of a sharpened cutting part called its point and the shank.
The point of the tool is bounded by the face (along which the chips slides as they
are cut by the tool), the side flank or major flank the end flank or minor flank
and the base. It is used to remove the materials from the workpiece. During the
cutting process, it produces metal chips.
As we know we perform several operations on the lathe (like turning, facing)
from the single-point cutting tool. Design and fabrication are very easy for this
tool. This tool can be made at a very cheaper rate as compared to others.

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Figure 8: Tool geometry of a single point cutting tool is mentioned in the above image.

Single – point Cutting Tool Geometry
Inclules:
- Shank: This is the main body of the tool. The shank is used to hold the tool (i.e
tool holder).
- Flank: The surface or surface below and adjacent to the cutting edge is called
flank of the tool.
- Face: The surface on which the chips slide is called the face of the tool.
- Heel: It is the intersection of the flan and the base of the tool. It is a curved
portion at the bottom of the tool.
-

Nose: It is the point where the side cutting edge and end cutting edge

intersects.

- Noise radius: The nose radius will provide long life and also good surface
finish with it a sharp point on the nose.
- Cutting edge: It is the edge on the face of the tool which removes the material
from the workpiece.

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Figure 9

Let’s explain each of these single point cutting tool angles one by one along
with their significance.
 The Rake Angles
The rake angle is an angle which is at the upper side of the cutting tool. There
are two types of rake angles which combine to form an effective rake angle (also
known as true rake angle or resistant rake angle). These two rake angles are:
- Back rake angle: Back rake angle is the angle between the face of the tool and
a line parallel to the base of the shank in the plane parallel to the side cutting
edge. The chip formation from the workpiece depends on the back rake angle of
the cutting tool.
- Side rake angle: Side rake angle is the angle by which the face of the tool is
inclined sideways. There are two major effects on the metal cutting process due
to rake angle. Rake angle affects the tool strength as well as it affects the cutting
pressure.
Tool having a negative rake angle will withstand more loading as compared
to a tool with positive rake angle. Tool having a positive rake angle helps in

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reducing the cutting force by allowing the chips to flow easily across the rake
surface.
There are few more functions of the rake angle:
- It allows the cop to flow in the convenient direction.
- It increases the tool life as it can reduce the cutting force required to
shear the metal and this also helps in reducing the power consumption.
- It improves the surface finish of the workpiece.
Now one more thing I want to add for the rake angles. The rake angles are of
two types:
Positive rake angle

Figure 10: The above image shows you the positive rake angle in a single point cutting
tool.

The positive rake angles reduce compression forces as well as friction between
the tool and workpiece. This results in thinner, cooler and less deformed chips.
The main disadvantage of increasing the rake angle is that, it reduces the
strength of the tool section and also reduces the heat conduction capacity.
Positive rake angles are more beneficial for cutting tough alloyed metals.

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Negative rake angle

Figure 11

Negative rake angles improve the strength of the cutting edge and they are
good for better heat conductivity.
Generally, negative of zero rake angle is made on carbide tools as well as

ceramic cutting tools.
These are brittle materials but they have the ability to withstand high
temperature and hence they can be used for high speed and continuous
machining processes. Negative rakes are generally preferred for the tools which
do not have good toughness.
As a result, negative rake causes high compression force and friction which
results in highly deformed hot chips
Few important things about negative rake angle
- Material like cast iron which is hard for machining, can be machined with
cutting tools having negative rake angles.
-

Cemented carbide tools are applicable for the high speed machining

operations. At such high operating speed, the rake angles have less effect on the

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