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Measurement of Tool Wear

This document provides instructions for an experiment to measure tool wear and evaluate tool life in turning mild steel. The experiment involves: 1) Machining mild steel with HSS or carbide tools and measuring tool wear over time using a microscope. Tool life is considered reached at 0.3mm flank wear or 0.15mm crater wear. 2) Recording flank wear measurements at regular intervals for different cutting speeds and feeds to generate tool life data. 3) Plotting flank wear growth over time and tool life curves to cutting speed to derive Taylor's tool life equation from the experimental results.

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Sourav Kayal
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448 views4 pages

Measurement of Tool Wear

This document provides instructions for an experiment to measure tool wear and evaluate tool life in turning mild steel. The experiment involves: 1) Machining mild steel with HSS or carbide tools and measuring tool wear over time using a microscope. Tool life is considered reached at 0.3mm flank wear or 0.15mm crater wear. 2) Recording flank wear measurements at regular intervals for different cutting speeds and feeds to generate tool life data. 3) Plotting flank wear growth over time and tool life curves to cutting speed to derive Taylor's tool life equation from the experimental results.

Uploaded by

Sourav Kayal
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Academy of Technology

Department of Mechanical Engineering


Machining and Machine Tools Laboratory (ME-691)
Assignments and Lab Experiments: 4

Measurement of tool wear and evaluation of tool life in turning mild steel by HSS or
carbide tool

1. Objective: Experimental study of pattern of wear and measurement of magnitude of


wear of cutting tool by actual machining using microscope aiming determination of life
of single point turning tool under different machining conditions.
2. Pattern of tool wear: After machining for some time the cutting tool at its dip fails
and mostly by gradual wear and often by fracture or severe plastic deformation. The span
of tool life place significant role on productivity, job quality and overall economy of
machining. Tool wear cannot be prevented but attempt should be made to delay the
failure by reducing the rate of growth of tool wear.
The usual pattern and significant indices of tool wear are indicated in fig.1.

Fig. 1 Usual pattern of tool wear and wear indices


The major indices used to consider tool failure are the
i. Average flank wear, VB
ii. The depth of crater wear, Kr
A cutting tool is generally said to have failed when VB reaches 0.3mm and Kr reaches
0.15 mm, due to rubbing against the chip and the work surface under high pressure,
temperature and speed. The tool attains wear at its rake face and flank mainly by
 Abrasion wear
 Adhesion wear
 Diffusing wear

Depending upon tool-work material and machining condition method.

3. Experimental determination of tool life


The life of a cutting tool is determined experimentally as indicated in fig. 2.

Fig. 2 Evaluation of tool life from growth of wear with machining time

4. Machine and equipments to be used:


 Machine tool – centre lathe
 Blank (job) – mild steel rod of given diameter and length
 Cutting tool – HSS or WC tool tip of given geometry.
 Optical microscope – interface with computer
 Cutting fluid – soluble oil
5. Experimental result and discussion:
The measured values of VB are monitored at regular intervals with progress of machining
under pre-set speed – feed (VC – S0) combinations which are to be recorded as indicated
in the table.
Table: - VB measured at different VC – S0 combination

VC S0 ENV Average flank wear after


(m/min) (mm/rev) Dry/Wet 1min 2 min 5 min 10 15 20
min min min

V1

V2

V3

V4

The experimental results are plotted as indicated in figure 3.

Fig. 3 Evaluation of tool life from experimentally determined flank wear


From fig. 3 tool life value are taken for different VC and the TL Vs VC curves are drawn
(fig.4)
Cutting
velocity,
Vc
(m/min)

Tool life, T (min)


(b)
(a)

Fig. 4 Cutting velocity Vs tool life

From the fig. 4 the taylor’s tool life equation is derived in the from VTn = C, where n and
C are determined from fig. 4(b)

6. Remarks and conclusions

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