a small presentation about machinability and Al machinability containing: Definition of Machinability Machinability of Aluminum Alloys How to improve the mach inability of Al alloy? Cutting force during machining of aluminum alloys Chip formation and chip segmentation Surface of Machined Aluminium Alloys MACHINABILITY RATINGS

1. MACHINABILITY OF
ALUMINIUM ALLOYS

2. CONTENT:
 Definition of Machinability
 Machinability of Aluminum Alloys
 How to improve the mach inability of Al
alloy?
 Cutting force during machining of
aluminum alloys
 Chip formation and chip segmentation
 Surface of Machined Aluminium Alloys
 MACHINABILITY RATINGS

3. DEFINITION OF MACHINABILITY:
 The term machinability refers to the ease with
which a metal can be machined to an acceptable
surface finish
 The term machinability includes all those
properties which are relevant for the machining
and cutting process:
 the wear of tools
 the necessary cutting force
 the resulting form of the chips
 the quality of the surface produced

5. DEFINITION OF MACHINABILITY:
Then.
 Machinability is not a material property which
can be defined using a single characteristic
parameter. It is, in fact, a complex technological
term.
 The machinability depends on both the physical
and chemical properties of the material_
aluminum as well on the fabrication process used
to produce it_.

6. MACHINABILITY OF ALUMINUM ALLOYS
 The use of materials with low specific weight is
an effective way of reducing the weight of
structures
 Aluminum alloys are among the most commonly
used lightweight metallic materials as they offer
a number of different interesting mechanical and
thermal properties.
 In fact, aluminum alloys as a class are considered
as the family of materials offering the highest
levels of machinability, as compared to other
families of lightweight metals such as titanium
and magnesium alloys.

7. MACHINABILITY OF ALUMINUM ALLOYS
 Aluminum alloys are classified under two classes:
cast alloys and wrought alloys
 Most wrought aluminum alloys have excellent
machinability.
 While cast alloys containing copper, magnesium
or zinc as the main alloying elements can cause
some machining difficulties

8. HOW TO IMPROVE THE
MACHINABILITY OF AL ALLOY?
 The machinability of alloys can be improved by
different treatment.
 Heat treatments, which increase hardness, will
reduce the built-up edge tendency during
machining.
 It has been found that heat treatment of 6061
especially,aging influences the forces only at low
cutting speeds, while at high speeds, the
influence is negligible because of the low
temperature rise seen in the cutting zone.

9. CUTTING FORCE DURING MACHINING OF
ALUMINUM ALLOYS
 While the cutting forces during the machining of
aluminum alloys are relatively low, they can
nevertheless provide a good indicator for a
comparison of different alloys under the same
machining conditions.
 A typical cutting force signal acting on the cutter
in the axial direction (thrust force Fz) during
drilling is presented in Figure.

10. CUTTING FORCE DURING MACHINING OF
ALUMINUM ALLOYS
 Portion a-b of the graph corresponds to the drill
point engagement into the workpiece
 while the portion b-c corresponds to the real
cutting. Portion b-c is usually employed to
estimate the cutting force or the energy required
to shape metals.

11. CUTTING FORCE DURING MACHINING OF
ALUMINUM ALLOYS
 Using an enlarged graph, It is possible to identify
the action of each flute of the cutter during the
cutting process.

12. CHIP FORMATION AND CHIP SEGMENTATION
 The chip shape and microstructure constitute a
good indicator of the deformation having occurred
during the machining process.
 Several research works have analyzed chip
formation in order to identify the optimal
conditions for improving machining and
machinability.
 Several tests were carried out in the laboratory
in order to characterize the chip shape during the
machining of aluminum alloys.
 Following Figure presents the chip morphology
obtained from scanning electronic microscopy
(SEM) as a function of cutting speed

14. SURFACE OF MACHINED ALUMINIUM
ALLOYS
 In general, the quality of the surface produced by
machining depends on three independent
parameters:
 The kinematical roughness
 The machined surface roughness
 External influences

15. SURFACE OF MACHINED ALUMINIUM
ALLOYS

16. MACHINABILITY RATINGS:
 Machinability ratings are “relative” ratings.They
compare the ease of machining an alloy to a
standard.
 TABLES:
 The tables on the below pages contain
machinability ratings for many alloys. The tables
in this Skill Builder were obtained from Tool and
Manufacturing Engineers Handbook, Volume 1,
Fourth Edition from the Society of
Manufacturing Engineers.

17. MACHINABILITY RATINGS:

18. THANK YOU