ABRASSIVE FLOW MACHINING
It is a process of polishing and smoothening
The abrassive media is flown across the surface to
be super finished either in a single direction or in 2
direction and is extrude through w.p,theirby
finishing the w.p and smoothening the surfaces.
CLASSIFICATION OF AFM MACHINE
One-way flow AFM processing pushes abrasive
media through the work piece in only one direction,
allowing the media to exit freely from the part.
The typical two-way flow AFM process uses two
vertically opposed cylinders to extrude an abrasive
media back and forth through or around passages
formed by the work piece and tooling . Abrasive
action occurs wherever the media enters and passes
through the most restrictive passages
Surface and edge finishing are achieved by rapid,
low-amplitude, oscillations of the work piece relative
to a self-forming elastic plastic abrasive polishing
The tool is a pad or layer of abrasive-laden elastic
plastic medium(similar to that used in two way
abrasive flow finishing),but typically higher in
viscosity and more in elastic.
PROPERTIES OF AFM
Deburring, radiusing, and polishing are performed
simultaneously in a single operation
AFM can produce true round radii even on complex
Reduces surface roughness by 75 to90 % on cast
and machined surfaces
AFM can process dozens of holes or multiple
passages parts simultaneously with uniform results
APPLICATION OF AFM
Dies and Molds
AFM IN AEROSPACE INDUSTRY
Improved surface quality
Enhanced high cycle fatigue strength
Optimized combustion and hydraulics
Extended component life
AFM IN AUTOMOTIVE INDUSTRY
Enhanced uniformity and
surface quality of finished
Increased engine performance
Increased flow velocity and
Improved fuel economy and
Extended work piece life by
reducing wear and stress
AFM IN DIES AND MOLD INDUSTRY
Reduced production costs
Increased production throughput
Enhanced surface uniformity, finish and cleanliness
Improved die performance and extend life of dies
AFM IN MEDICAL INDUSTRY
Eliminate the surface imperfections where
dangerous contaminates can reside
Improved functionality, durability and
reliability of medical components
Enhanced uniformity and cleanliness of
Extended component life
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459, Volume 3, Issue 2 ,February
Jose Cherian, Dr. Jeoju M Issac
Research Scholar, Karpagam University, Eachanari Post, Coimbatore-
Professor, Department of Mechanical Engineering, MA College of
Engineering Kothamangalam, Kerala, India.
Gov K, Eyercioglu O, Cakir MV. Hardness Effects on Abrasive Flow
Journal of Mechanical Engineering. 2013; 59: 626- 31.
Eyercioglu O, CAKIR MV, GOV K. Influence of machining parameters on
the surface integrity in small-hole electrical discharge machining.
Proceedings of the Institution of Mechanical Engineers, Part B: Journal
of Engineering Manufacture. 2013.
RESEARCH PAPER 1
Effect of Process Variables in Abrasive Flow
• International Journal of Emerging Technology and Advanced
• Website: www.ijetae.com (ISSN 2250-2459, Volume 3, Issue 2,
• Jose Cherian, Dr. Jeoju M Issac
1. Research Scholar, Karpagam University, Eachanari Post,
2. Professor, Department of Mechanical Engineering, MA College of
Engineering Kothamangalam, Kerala, India.
PROCESS MODELLING AND
Williams and Rajurkar developed a stochastic model of AFM generated surfaces by
Data Dependent systems (DDS) methodology.
Estimated the ratio of surface roughness peak height (RZ) to the centerline average
surface roughness value (Ra) by DDS methodology and found to be between 1.4 and
2.2 micrometers for the AFM process.
A large wavelength corresponds to the main path of the abrasive while the small
wavelength is associated with the cutting edges.
They proposed an expression for estimating the abrasive grain wear and the number
of active grains(Cd). The estimated value of Cd can be used as a cutting life criterion
For small number of cycles, its value should remain fairly stable but with more and
more processing, the abrasive particles may fracture and thereby increasing the Cd
value. The downturn of Cd value indicates that the medium has been absorbed too
much abrasives and needs replacement.
Carried out simulation of finished surface profiles and material removed considering
the interaction of abrasive grain with work piece material.
Proposed a mathematical simulation model to determine the characteristics of the
medium flow during finishing and its experimental verification.
They reported that a linear relationship exists between shear stress acting on the
surface and the layer thickness of material removed.
RESEARCH PAPER 2
This paper conducted on the finishing of difficult to
machine materials like Ti6Al4V.
The influence of the AFM process on Ti6Al4V
workpieces were investigated.
The results show that the white layer formed during
WEDM is successfully removed by AFM in a few
cycles for each workpiece.
Ti6Al4V displays high strength, corrosion and heat
Are commonly used in high temperature
applications such as turbine blades and rocket
It is considered more difficult to finish using
conventional techniques (grinding, lapping, etc.)
than other metallic materials.
The experiments were performed on Ti6Al4V.
The specimens were cut from the slabs by using
wire electro discharge machine (WEDM) to
5x10x20 mm as shown in Fig.
The WEDM parameters kept constant for all
specimens to ensure the pre-surface characteristics
of the specimens.
Surface roughness values of the specimens before
Physical, mechanical and thermal properties of
THE ABRASIVE FLOW MACHINE
In this study a two-way AFM machine that has two
vertically opposed chambers was used (shown in
The machine contains of a main frame, hydraulic unit,
electronic control unit and heating-cooling unit.
The specifications of the machine are given in Table3.
The hydraulic unit ensures adequate movement and
media pressure that can be automatically configured.
The control system is designed to control the volume of
abrasive media and the number of cycles.
One cycle in two-way AFM process is composed of
reciprocating motion of forward and backward of the
piston ram in the media cylinder.
Thus cycle time depends on the piston speed and one
cycle in the experimental study takes 2 minutes.
THE ABRASIVE MEDIA
The abrasive media that were prepared for the
present study is a mixture of polymeric carrier,
silicon carbide (SiC) abrasive particles, and 10% of
The specifications of the abrasive media are
summarized in Table4
Before performing the experiments, the abrasive
media is run for 3–5 cycles with a trial workpiece,
so as to get uniform mixing.
Preparing the abrasive media was the hardest
They have used Garnet,SiC, B4C and Al2O3 as a
raw material of abrasive media.
They were washed by them as shown in Fig. and
after that they were sieved to get optimum mesh
size of this material.
The experiments were performed on the Ti6Al4V.
The workpiece holder (seeFig.) was used
to hold the specimens allowing the flow
of abrasive media through the WEDMed
surfaces with an opening of 10x20 mm.
12 litres of abrasive media was flown
through in each cycle.The experiments
were carried out for 1,3,5,10,20,50 and 100
The AFM pressure was 10 MPa and flow rate was 3 l/min.
The experiments were repeated for three specimens in each
condition and the averages of the 5 surface roughness
measurements were taken by using Mitutoyo SJ 401 surface
measuring machine,with the cut off length 0.8 mm.
The specimens were cleaned by ethyl alcohol and weighed
before and after the experiment by using SHIMADZU AUX220
RESULTS AND DISCUSSION
Measurements of surface roughness
From the Fig.5 the surface roughness value decreased with increase in
number of cycles for each specimens. The surface roughness
(Ra)decreased significantly in the third cycle for Ti6Al4V specimens, the
surface roughness after 20 cycles for Ti6Al4V are decreased slightly.
The Fig.6 shows that the material removal (MR) increases nonlinearly with the
increase in the number of cycles. And the rate of MR decreasing with number of
cycles. The reason for this slight decrease in material removal rate can be explained
as the result of asperities on the workpiece surface before AFM. When the abrasive
particles within the media machine the peaks, they become flatter than before and in
the following cycles, the material removal is decreased.In the case of the Ti6Al4V
workpiece total material removal is low.
The EDMed surface is unlike that produced by any traditional machining process; it
is characterized by globules and random debris of re-deposited and recast
material. The high temperature changes the metallurgy of the material. The region
affected by these thermal changes is referred to as the heat-affected zone (HAZ).
The HAZ is included of a recast layer (white layer) of material that has been melted
and re-solidified at the surface, white layer that is harder than the original material;
contains micro cracks.
Microscopic photographs of the white layers for four groups of specimens are
given inthe first cycles of the AFM process, the white layer is removed for
specimens which were finished by B4C and SiC based media. From Fig.5 the
improvement in the surface roughness values are similar and best improvement
was occurred in specimens which were finished by B4C and SiC based media
these results are well agreement to each other.
After removal of the white layer, abrasion behaviours of the four groups were
changed. In the specimens (finished by B4C and SiC based media) has less
smearing and ploughing. And no indentation of the abrasive particles to the
surfaces was observed and the final surface roughness is better.
For Al2O3 based media finished specimen, the globules were fully removed from
the surface in the fifth cycle but the lay of craters were fully removed after twentieth
cycle and also have less ploughing. For specimen that were finished by Garnet
based media, the globules were fully removed in the fifth cycle, but the debris was
fully removed after fiftieth cycle.
Fig. illustrates the removal of white layer with respect to the number of AFM cycles
for DIN 1.2379 55 HRC specimens. The results of SEM images and the sectional
microscopic views are in well agreement. The white layers were fully removed in
the first cycle of B4C and SiC based media. In the case of Al2O3 and Garnet based
media, five and twenty cycles were required to fully remove the white layers.
From the experimental results, the following conclusions have been
The white layer formed during WEDM is successfully removed by
using all types of abrasives.
The results of SEM images and the sectional microscopic views are
in well agreement. The white layers were fully removed in the first
cycle of B4C and SiC based media. In the case of Al2O3 and Garnet
based media, five and twenty cycles were required to fully remove
the white layers.
Although the trends of surface roughness measurements are similar
for all media groups, the results show that the media prepared by
B4C and SiC has more surface improvement than Al2O3 and Garnet.
The surface improvement nearly the same for B4C and SiC therefore,
SiC can be preferred due to its lower cost and better performance.
According to the desired finishing condition the Garnet can be used
for its better cost.