Forrces in Truning and Drilling -131_2

7/27/2019 Forrces in Truning and Drilling -131_2

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M.E 407 Lab Lectures: Prepared by Mr. Hassan Iqbal , Mr Mohudin Ahmed & Dr. Anwar Khalil Sheikh

Machining Processes

Partsare manufactured by removing or cutting

the materials from the work pieces


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Cutting Forces and Power

Forces and Power requirements in metal cutting

must be known in advance to select a machine tool with enough power

select a cutting tool of withstanding the cutting

avoid excessive distortion, maintain dimensional tolerances

workpiece is capable of withstanding the cutting forces

without excessive distortion

Relative Movements Between Workpiece and Cutting ToolGenerate Forces and Powers


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Objectives

1. To review the Turningand Drillingprocesses and theprocess variables (speed, feed and depth of cut) in metalcutting.

2. To familiarize the students with the force measuringinstrumentation and equipment.

3. To familiarize the students with the type and methods of

measuring forces in Turning as well as in Drillingprocesses.

4. To study the effect of process variables on forces in metalcutting.


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Turning

Turning is a machining process performed on a lathe in which a single point toolremoves material from a rotating cylindrical workpiece. The cutting tool is fed

linearly and in a direction parallel to the axis of rotation of the workpiece as shown in

the figure below.


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Forces in Turning

Tangential or Cutting Force = Fz

Axial or Thrust Force = Fx

Radial Force = Fy

Fy


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Cutting Parameters in Turning

Original Diameter of Workpiece = Depth of Cut =

Final Diameter of Machined part= Feed rate =

Length of Cut on Workpiece = Rotational Speed = rpmN

revmmf

mmd

,

./,

,

mmL

mmD

mmD

f

o

,

,

,


7/33M.E 407 Lab Lectures: Prepared by Mr. Hassan Iqbal , Mr Mohudin Ahmed & Dr. Anwar Khalil Sheikh

Design of Experiments



Experimental Setup

Dynamometer Workpiece

Cutting

Tool



Data Recording

Charge Amplifier

Data Acquisition and

Display



DynoWare

Data Accusation Software



Data Channels



Acquisition parameters



Channels Trigger



Adding Cutting Parameters



Hardware setting Display


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Press Meas Button first

then Press Go


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Computational Table


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Turning VsOrthogonalCutting

to w Fc Ft

f d Fz Fx


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Formulas in Turning

.sec1000

.sec601000

1tan

3

1

mmfdVxMRR

mx

DNV

rSin

rCos

t

fr

c

toand are input known variables and tcis measured from experiment Cutting force, Fc, andThrust force, Ftare measured from Experiments

by using Tool Dynamometers.

Then;


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Calculation of Forces

RFt

Fc

F

N

Cutting

Tool

Chip

Fn

Fs

Tool Friction Force F = Fcsin + Ftcos = R sin N= Fccos + Ftcos = R cos

Balanced Shear Force

Fs= Fccos- Ftsin

Fn= Fcsin+ Ftcos Resultant Force

R=Fs/Cos(+ - ) Coefficient of friction

= F/N = tan (0.52.0)

tc

to

(- )

)(

Sin

fdA

A

F

s

s

s


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Power and HP in Metal Cutting


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Report Writing

1. Cover Page2. Objectives of Experiment3. List of Equipment and tooling4. Neat and clean sketch of Experimental set up5. A brief procedure of experiment (step by step)6. Complete the Table 1 and Table 2 by using the Microsoft Excel for each test condition.7. Sample calculation for one test by using the formulas.8. Plot Fcand FtvsCutting speed (V) i.e., experiment number 1-69. Plot Fcand FtvsFeed Rate (f) i.e., experiment number 7-1210.Plot Fcand FtvsDepth of Cut (d) i.e., experiment number 13-18

11.Develop empirical model of Fc given by the equation:

dkFc

VkFc

fkFc

3

2

1

12. Discussion of the Results13. Conclusions and Comments

Conclude your report with the remarks, What you learned from theexperiment and any further improvement in the experiment.


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Drilling Process

Drilling is used to create round holes in workpiecesusing a rotating tool with two cutting edges.

.drill bitortwist drillThis rotating tool is called a

This operation is normally performed on a drill press.


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Drilling Process Variables

f (mm/rev.)

N (rpm)

D (mm) n=number of teeth on cutter


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Force and Moment in Drilling


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Design of experiment in Drilling

TABLE 1: DATA SHEET DRILLING PROCESS

Workpiece Material: Twist Drill Material:

Material Spcific Energy: Ut W.s/mm3 Twist Drill Point Angle:

Using Coolant [Y/N] : Machine Tool Name: HP:

TEST ROTATIONAL AXIAL TWIST DRILL AXIL TORQUE

NO. SPEED FEED RATE DIAMETER FORCE or MOMENT

N (rpm) f (mm/rev.) D (mm) Fz (N) M (N-m)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18


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Experimental Setup

Dynamometer

Workpiece

CuttingTool


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Data Recording


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Computational Table

TABLE 2: COMPUTATIONAL SHEET DRILLING

TEST CUTTING FEED TOOTH MRR FORCES (N) TOTAL TOTAL

NO. SPEED SPEED LOAD mm3/sec. CUTTING THRUST POW ER CUTTING

V (m/min.) F (mm/min) TL Fc Ft Pt (Watts) HP

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18


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Drilling VsOrthogonal Cutting


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Formulas in Drilling

746

)(

5

5.0

sec604

sec601000

32

WattsPHP

MRR

Pu

Sin

FzF

D

MF

Nn

V

T

mmNfDMRR

mx

DNV

t

tt

t

c

L


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Report writing for Drilling

1. Cover Page2. Objectives of Experiment3. List of Equipment and tooling4. Neat and clean sketch of Experimental set up5. A brief procedure of experiment (step by step)6. Complete the Table 1 and Table 2 by using the Microsoft Excel for each test condition.7. Sample calculation for one test by using the formulas.8. Plot Fzand M vsCutting speed (V) i.e., experiment number 1-69. Plot Fzand M vsFeed Rate (f) i.e., experiment number 7-1210.Plot Fzand M vsDepth of Cut (d) i.e., experiment number 13-18

11.Develop empirical model of Fz given by the equation:

VkF

fkF

z

z

2

1

12. Discussion of the Results13. Conclusions and Comments

Conclude your report with the remarks, What you learned from theexperiment and any further improvement in the experiment.

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Forrces in Truning and Drilling -131_2

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