EXPERIMENTAL INVESTIGATION AND OPTIMIZATION OF MILLING

PROCESS PARAMETERS FOR ALUMINIUM

Maharana Ravindra1, Monpara Malharkumar

2, Solanki Vinit

3, Patel Mohitkumar

4

Student, Mechanical department, Laxmi institute of Technology, Sarigam-Valsad. Gujarat

Corresponding Author Detail:

Maharana Ravindra

Student, Mechanical department,

Laxmi institute of Technology,

Sarigam-Valsad, Gujarat.

Internal Guide Detail:

Mr. Vinit Patel

Assistant Professor, Mechanical department,

Laxmi institute of Technology,

Sarigam-Valsad. Gujarat.

ABSTRACT

In this study investigation of VMC operation parameters for aluminium using full factorial

method. Spindle speed, feed rate, DOC on vertical milling machine. The material used is

Al6061 and will conduct on basis of full factorial method. The carbide tools are used while

conducting experiment. In this experiment the response parameters are surface roughness and

MRR for wall finish.

KEYWORDS Aluminium, Full Factorial Method, Wall Finish, Vertical Milling Machine.

INTRODUCTION

Milling is the machining process of using rotary cutters to remove material from a workpiece

by advancing (or feeding) in a direction at an angle with the axis of the tool. It covers a wide

variety of different operations and machines, on scales from small individual parts to large,

heavy-duty gang milling operations. It is one of the most commonly used processes in

industry and machine shops today for machining parts to precise sizes and shapes. Milling is

a cutting process that uses a milling cutter to remove material from the surface of a

workpiece. The milling cutter is a rotary cutting tool, often with multiple cutting points. As

opposed to drilling, where the tool is advanced along its rotation axis, the cutter in milling is

usually moved perpendicular to its axis so that cutting occurs on the circumference of the

cutter. As the milling cutter enters the workpiece, the cutting edges (flutes or teeth) of the tool

repeatedly cut into and exit from the material, shaving off chips (swarf) from the workpiece

with each pass. The cutting action is shear deformation; material is pushed off the workpiece

in tiny clumps that hang together to a greater or lesser extent (depending on the material) to

form chips. This makes metal cutting somewhat different (in its mechanics) from slicing

softer materials with a blade.

The milling process removes material by performing many separate, small cuts. This is

accomplished by using a cutter with many teeth, spinning the cutter at high speed, or

advancing the material through the cutter slowly; most often it is some combination of these

three approaches. The speeds and feeds used are varied to suit a combination of variables.

The speed at which the piece advances through the cutter is called feed rate, or just feed; it is

most often measured in length of material per full revolution of the cutter.

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There are two major classes of milling process:

In face milling, the cutting action occurs primarily at the end corners of the milling cutter.

Face milling is used to cut flat surfaces (faces) into the workpiece, or to cut flat-bottomed

cavities.

In peripheral milling, the cutting action occurs primarily along the circumference of the

cutter, so that the cross section of the milled surface ends up receiving the shape of the

cutter. In this case the blades of the cutter can be seen as scooping out material from the

work piece. Peripheral milling is well suited to the cutting of deep slots, threads, and gear

teeth.

Figure-1

The experiment is conducted on CNC milling machine, which is also known as VMC

machine.

Types of CNC milling machine:

1. HMC (horizontal milling machine)

2. VMC (vertical milling machine)

HMC

Figure-2 horizontal machining center (HMC)

A horizontal machining center (HMC) is a machining center with its spindle in a horizontal

orientation. This machining center design favors uninterrupted production work. One reason

for this is that the horizontal orientation encourages chips to fall away, so they don't have to

be cleared from the table.

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VMC

Figure-3 verticle machining center (HMC)

A VMC is a type of CNC machine, typically enclosed and most often used for cutting metal.

They are usually very precise and very expensive. A modern VMC is controlled by CNC.

The CNC is the computer and motion part of the machine. The rest is the frame and the

spindle (cutting head). In addition to VMC, CNC can also control lasers, 3D printers, water

jets, plasma cutters, saws, etc.

Most CNC milling machines (also called machining centers) are computer controlled vertical

mills with the ability to move the spindle vertically along the Z-axis. This extra degree of

freedom permits their use in diesinking, engraving applications, and 2.5D surfaces such

as relief sculptures. When combined with the use of conical tools or a ball nose cutter, it also

significantly improves milling precision without impacting speed, providing a cost-efficient

alternative to most flat-surface hand-engraving work.

TOOL

Figure-4 End milling cutter

An end mill is a type of milling cutter, a cutting tool used in industrial milling applications. It

is distinguished from the drill bit in its application, geometry, and manufacture. While a drill

bit can only cut in the axial direction, a milling bit can generally cut in all directions, though

some cannot cut axially. This experiment uses carbide tool of diameter 20mm.

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OBJECTIVES

To get the optimum parameters for milling process for the material aluminium like,[1]

Surface roughness (Ra)

Material removal rate = feed*doc*woc mm3/sec

Where v= cutting speed

f= feed rate

d= depth of cut

INTRODUCTION TO FULL FACTORIAL DESIGNING

• Factorial designs were used in the 19th century by John Bennet Lawes & Joseph Henry

Gilbert of the Roth Amsted Experimental Station.

• Full factorial experiment is an experiment whose design consists of two or more factors,

each with discrete possible levels, high, medium and low, and whose experimental

units take on all possible combinations of these levels across all such factors.

TECHNICAL SPECIFICATION OF VMC

TABLE SIZE 1000X530 mm

T-SLOT DIMENSIONS 4x18x100 mm

MAX. LOAD ON TABLE 800 Kg

PARAMETERS CONSIDERED FOR EXPERIMENT

• Input Parameters :Speed, Feed, Width of cut

• Output Parameters :Surface roughness (RA), Material removal rate (MRR)

SPECIMEN

Material: Aluminium 6061

Figure-5 Raw material

Figure-6 Finished material

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Figure-7 No of Experiment to be conducted

Figure-8 After Measuring Surface Roughness

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SURFACE ROUGHNESS INSTRUMENT

ANALYSIS

MAIN EFFECT PLOT FOR RPM AND FEED (SURFACE ROUGHNESS)

MAIN EFFECT PLOT OF RA FOR WOC

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MAIN EFFECT PLOT FOR RPM AND FEED (MRR)

MAIN EFFECT PLOT FOR WOC (MRR)

COUNTER PLOT FOR RA VS RPM

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COUNTER PLOT OF RA vs FEED

COUNTER PLOT OF MRR vs RPM

OPTIMIZATION PARAMETERS BY GRAYS RELATION

STD RUN RPM Feed WOC Ra MRR

1 6 4500 650 0.3 0.42 2.6325 13.5

2 19 4500 750 0.3 0.42 3.0375 13.5

3 21 4500 850 0.3 0.48 3.4425 13.5

4 8 5500 650 0.3 0.34 2.6325 13.5

5 18 5500 750 0.3 0.37 3.0375 13.5

6 17 5500 850 0.3 0.39 3.4425 13.5

7 1 6500 650 0.3 0.27 2.6325 13.5

8 9 6500 750 0.3 0.29 3.0375 13.5

9 15 6500 850 0.3 0.3 3.4425 13.5

10 11 4500 650 0.6 0.31 5.265 13.5

11 22 4500 750 0.6 0.36 6.075 13.5

12 20 4500 850 0.6 0.38 6.885 13.5

13 10 5500 650 0.6 0.21 5.265 13.5

14 24 5500 750 0.6 0.29 6.075 13.5

15 25 5500 850 0.6 0.3 6.885 13.5

16 12 6500 650 0.6 0.14 5.265 13.5

17 3 6500 750 0.6 0.18 6.075 13.5

18 26 6500 850 0.6 0.2 6.885 13.5

19 5 4500 650 0.9 0.34 7.8975 13.5

20 16 4500 750 0.9 0.37 9.1125 13.5

21 23 4500 850 0.9 0.42 10.328 13.5

22 14 5500 650 0.9 0.26 7.8975 13.5

23 7 5500 750 0.9 0.28 9.1125 13.5

24 4 5500 850 0.9 0.27 10.328 13.5

25 27 6500 650 0.9 0.2 7.8975 13.5

26 13 6500 750 0.9 0.22 9.1125 13.5

27 2 6500 850 0.9 0.23 10.328 13.5

Max 0.48 10.328

Min 0.14 2.6325

Ra MRR Grade

Sequencing

DOC

PRE Normaliation

MRR

0.817844

0.713984

0.71345 1 0.28655 0

0.751462 0.842105 0.248538 0.157895

0.815789 0.684211 0.184211 0.315789 0.671836

0.785

0.653163

0.622807 1 0.377193 0

0.584795 0.842105 0.415205 0.157895

0.652047 0.684211 0.347953 0.315789 0.601279

0.689579

0.592159

0.181287 1 0.818713 0

0.321637 0.842105 0.678363 0.157895

0.412281 0.684211 0.587719 0.315789 0.53629

0.624648

0.629702

0.807018 0.552632 0.192982 0.447368

0.862573 0.447368 0.137427 0.552632

1 0.342105 0 0.657895 0.715909

0.517598

0.503855

0.51462 0.552632 0.48538 0.447368

0.561404 0.447368 0.438596 0.552632

0.774854 0.342105 0.225146 0.657895 0.560667

0.470911

0.452324

0.292398 0.552632 0.707602 0.447368

0.336257 0.447368 0.663743 0.552632

0.482456 0.342105 0.517544 0.657895 0.461599

0.432204

0.434997

0.511696 0.105263 0.488304 0.894737

0.546784 0.052632 0.453216 0.947368

0.616959 0 0.383041 1 0.449779

0.381373

0.383838

0.263158 0.105263 0.736842 0.894737

0.315789 0.052632 0.684211 0.947368

0.409357 0 0.590643 1 0.395889

0.345912

0.359408

0 0.105263 1 0.894737

0.160819 0.052632 0.839181 0.947368

0.163743 0 0.836257 1 0.353756

Ra

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Here the run 27 is the best optimize parameters obtained. By running on this parameter we

can get best surface finishes a maximum material removal rate.

APPLICATION

Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles,

spacecraft, etc.) as sheet, tube, and castings.

Packaging (cans, foil, frame of etc.).

Food and beverage containers, because of its resistance to corrosion.

Construction (windows, doors, siding, building wire, sheathing, roofing, etc.)

A wide range of household items, from cooking utensils to baseball bats and watches

Street lighting poles, sailing ship masts, walking poles.

High surface (wall) finish aluminium is used in making bores of cylinder

High precision machines(diamond cutting, laser cutting, aircraft, space equipment etc.,)

CONCLUSION

The experiment conclude that by using the full factorial method we should get best results.

As this method uses 27 results from three given parameters. The experiment result shows that

in this milling operation high cutting speed, average feed and high width of cut gives best

surface finishes with high material removal rate.

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