The Machinability of Aluminum

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The Machinability of Aluminum

Group 32

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contentIntroductionMachining of

aluminumThe Machining

Process1-Forms of

Aluminum Chips2- Surface of

Machined Aluminum Alloys

3- Tool wear and tool life

4- Cutting Force for Machining Aluminum

ApplicationsReferences

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IntroductionDefinition of Machinability :The machinability of a material

can be defined as the ease with which it can be machined.

This depends on the physical properties of the material, as well as on the cutting conditions.

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Why we use Aluminum in machining?

Aluminum alloys are characterized by two main properties:

1-The cutting temperature. (a maximum of 600 °C compared with 1000 °C for steels)

2-Their low density reduces inertia forces and allows high rotation speeds.

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Machining of aluminum

Aluminum alloys are among the most commonly used lightweight metallic materials as they offer a number of different interesting mechanical and thermal properties.

They are relatively easy to shape metals, especially in material removal processes, such as machining.

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Machining of aluminum Aluminum alloys as a class are

considered as the family of materials offering the highest levels of machinability

Aluminum alloys possess physical properties for good machinability, in terms of (cutting tool life- greater productivity - low specific cutting forces.)

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The Machining Process

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1-Forms of Aluminum Chips

It is an important criterion, especially when one bears in mind the very large volume of chips created while machining aluminum.

Pure aluminum and soft wrought alloys produce extremely long chips, making it essential to introduce chip breakers on the tools.

High-strength wrought alloys (e.g. AlMg5(5019), AlMgSi1(6082) present no problems as far as chip form is concerned.

Hypoeutectic casting alloys (G-AlSi8Cu3, G-AlSi10Mg etc.) lead to the formation of short coiled and spiral chips which can be removed easily.

Eutectic casting alloys (G-AlSi12) tend to produce longer chips.

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1-Forms of Aluminum Chips

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2 -Surface of Machined Aluminum Alloys

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3 -Tool wear and tool life

The tool wear while machining aluminum occurs due to abrasion of the free surface.

Wear increases with the number of large hard particles which are embedded in the aluminum workpiece.

Such particles could be primary precipitations of silicon particles in a hypereutectic alloy. This is the reason that aluminum castings cause high wear of tools.

The wear is extremely high in the case of cast.Wrought alloys with low silicon contents cause

minimum tool wear.

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3 -Tool wear and tool life

Tool life is the time the cutting edge can be used until it is worn out

The correlation between cutting speed, v, and tool life, T, Vc=C.T1/k

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4 -Cutting Force for Machining Aluminum

Different alloys have varying specific cutting forces, the variations being however, relatively small.

In general one can assume that the specific cutting force for aluminum is

about 30 % that of steel.

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6 -Cutting Force for Machining Aluminum

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Applicationscarburetor parts,

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Applicationsclock parts

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Applicationsgears, knobs, camera parts,

gears, pipe stems and filters, radio parts, mobile phones, tripod fittings, machine parts.

Aluminum gears for Polaris Industries

(Racing)

Apple 6000 series

aluminum phones

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Aluminum Alloys suitable for machining

- EN- 2011 is referred to as a free machining alloy due to its excellent machining properties. -The most common tempers for 2011 aluminum are: T3 – Solution heat treated, cold worked and naturally aged T6 – Solution heat treated and artificially aged

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Aluminum Alloys suitable for machining

when greater corrosion resistance is required leads to 6262 T9 being used  with excellent mechanical properties and good corrosion resistance.

-Both 2011 and 6262 are commonly supplied in bar form.

-When machining of plate aluminum is required, the grade selected is 6082. Alloy 6082 A popular heat treatable alloy. Medium strength is combined with good, welding, corrosion resistance and machinability.

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Tools for aluminum machining

1. Cutting force Important characteristics of

PLANSEE TIZIT inserts: Rake angle > 25°increasing

the rake angle by one degree the cutting force is reduced by ~1.5%.

Sharp, uniform cutting edge. Extra-smooth rake face. 2. Tool life Important characteristics of

PLANSEE TIZIT inserts: extremely wear resistant

hard metal grades optimized coating extra-smooth rake face

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Tools for aluminum machining 3. Surface finish Important characteristics

of PLANSEE TIZIT inserts: extra-smooth rake face optimized micro-geometry

of the cutting edge fine grain substrates 4. Chip formation Important characteristics

of PLANSEE TIZIT inserts: aluminum specific chip

grooves reduced friction between

chip and rake faceUnfavorab

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TOOLS FOR ALUMINUM MACHINING

1 - Very good machinability5 - Bad machinability

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References 

Machining and Machinability of Aluminum Alloys, Author: V. Songmene, R. Khettabi, I. Zaghbani, J. Kouam, and A. Djebara, École de technologie supérieure (ÉTS), Department of Mechanical Engineering, Canada.

TALAT Lecture 3100, prepared by P. Johne, Aluminium-Zentrale e.V., Düsseldorf.

PLANSEE TIZIT company, Plansee Tizit Aktiengesellschaft,Tools for aluminium machining.