This document discusses two abrasive finishing processes: abrasive flow machining (AFM) and magnetic abrasive finishing (MAF). AFM involves extruding an abrasive-laden putty between a workpiece and tooling to remove material, allowing for burr removal, radiusing, and polishing of complex shapes. MAF uses magnetic iron particles coated with abrasive grains to polish rod and flat surfaces. Both processes allow for close tolerances, intricate surface features, and machining of hard materials with minimal material removal due to thin chip formation.
2. Abrasive finishing processes
โข The need for high accuracy and efficiency
machining of difficult- to- machine materials is
making the application of abrasive finishing
technology.
3. Advantages
โข Because of extremely thin chips produced in
abrasive machining, it allows:
โข Better surface finish
โข Close tolerances
โข Generation of more intricate surface
features. &
โข Machining of harder and difficult to machine
materials.
4. Abrasive finishing processes
โข The two important abrasive finishing
processes are:
1. Abrasive Flow Machining
2. Magnetic Abrasive finishing
5. 1. Abrasive Flow Finishing
โข AFM is a kind of finishing process in which a small
quantity of material is removed by flowing a
semisolid abrasive laden putty over the surface to be
finished.
โข The media has high viscosity that it can be held
between fingers like a rubber ball which can be
deformed by applying little pressure.
โข Two vertically opposed cylinders extrude abrasive
media back & forth through passages formed by w/p
& tooling or by w/p alone.
7. Advantages
โข This process is good for operations like
deburring, radiusing, polishing & removing
recast layer etc.,
โข The process can produce tens of parts at the
same time to enhance productivity.
โข Same machine can be use to do a variety of
jobs by changing tooling, machining
parameters, media and abrasives.
8. Abrasive Flow machining system
โข It consists of three elements
1. Machine
2. Tooling &
3. Media
9. 1. Machine
โข Consists of two cylinders which are placed
vertically in opposite direction.
โข Work piece is sandwiched b/w the two
cylinders
โข The enclosed w/p area through which the
media is forced is called the โextrusion
passageโ.
10. 2. Tooling
โข Which is used to confine and direct the flow of
media to the appropriate areas.
โข Tooling for AFM machine is designed with two
aims:
1. To hold the parts in position &
2. To contain the media and direct its flow.
โข Internal surfaces
โข External surfaces.
11. 3. Media
โข It consists of base material & abrasive grits.
โข Base material is viscoplastic/ viscoelastic material
made up of organic polymer, & hydro carbon gel.
โข Types of abrasives used are Al2O3 , SiC, cubic boron
nitride and diamond.
16. Magnetic Abrasive Finishing Process
โข Initially MAF process was developed by US.
โข Japanese researches followed this work and
conducted research for fine polishing
applications.
โข Finishing of rod and finishing of flat surfaces
can de done.
โข Granular magnetic abrasives composed of
ferromagnetic material (iron particles) and
abrasive grains (Al2O3 , SiC or diamond).