1. The document discusses additive manufacturing and 3D printing of polymers. It notes that polymers are among the cheapest materials for 3D printing and lists some common plastics used, including ABS, PLA, polyamide, and nylon.
2. The document then covers various topics related to polymers, including classifications of polymers, molecular weight, polymer processing techniques, and metal powder characterization. It provides examples and definitions for these topics.
3. The remainder of the document discusses powder metallurgy processing techniques like compaction, sintering, defects in sintering, and applications of powder metallurgy. Processing steps like die pressing, CIP, HIP, slip casting, and
1. Santosh . V. Janamatti M.Tech(Ph.D)
Assistant Professor, BITM,ME Ballari
6/15/2021
Santosh . V. Janamatti M.Tech(Ph.D)
Assistant Professor, BITM,ME Ballari
1
Module-3
2. IntroductIon
Additive manufacturing
increasing in their practical
And engineers are starting
and how they could be the
Rather than looking
conventional manufacturing
Materials like polymers
significant part in determining
process to be used
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IntroductIon
process are gradually
practical applications
starting to figure out where when
most useful
completely replace all
manufacturing technique.
and metals are playa a
determining how and where the
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3. In AM process polymers are amongst the cheapest
materials and can be used widely for commercial
printing .
Common plastics can be used in 3D Printing
1. ABS 6. Glass filled nylon
2. PLA 7. Epoxy resin
3. PC 8. Wax
4. Polyamide 9. Photopolymer resins
5. Nylon 12
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In AM process polymers are amongst the cheapest
materials and can be used widely for commercial 3d
Common plastics can be used in 3D Printing
6. Glass filled nylon
7. Epoxy resin
8. Wax
9. Photopolymer resins
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4. Polymers
Polymers are long chain
molecules produced by
linking small repeat units
(monomers) together.
There are many ways to link
different types of monomer
to form polymer.
Polymers exhibit very
different physical properties
compared to monomers
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Classification of Polymers.
1. Natural & Synthetic polymer
Ex. For natural polymers are cotton,
Ex. For synthetic polymer are Polyethylene,
2. Organic & Inorganic polymer
Organic polymers are essentially
synthetic polymers are organic polymers
Inorganic polymers on the other hand
Glass & Silicon rubber
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Classification of Polymers.
cotton, silk, wool, rubber, cellulose & leather
Polyethylene, PVC, Nylon & Terylene.
polymer
made of carbon atoms & majority of
polymers.
hand contains no carbon atoms for ex.
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3. Thermo Plastics & Thermoset polymers.
Ex. For thermo plastic are polyethylene, PVC, ABS, polystyrene etc.,
Ex. for Thermoset polymers are Epoxy, Phinolex & Polyester.
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3. Thermo Plastics & Thermoset polymers.
Ex. For thermo plastic are polyethylene, PVC, ABS, polystyrene etc.,
Ex. for Thermoset polymers are Epoxy, Phinolex & Polyester.
7. Molecular weight(Mw)
The molecular weight of a polymer is a way of
describing how long the polymer chains are.
Each monomer has a molecular weight, adding the
monomers together to make polymers increases the
molecular weight.
The longer the chain, the higher the molecular weight
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Molecular weight(Mw)
The molecular weight of a polymer is a way of
describing how long the polymer chains are.
Each monomer has a molecular weight, adding the
monomers together to make polymers increases the
The longer the chain, the higher the molecular weight
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8. Number average molecular weight(mN)
The number average molecular weight is the statistical average
molecular weight of all the polymers chains in the sample and is it
defined by:
Mn= ∑ Ni Mi/ ∑Ni
Where, Mi- is the molecular weight of a chain and
Ni- is the number of chains of that molecular weight
Mn can be predicted by polymerization mechanism and is
measured by methods that determine the number of molecules in
sample of a given weight
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Number average molecular weight(mN)
The number average molecular weight is the statistical average
molecular weight of all the polymers chains in the sample and is it
is the molecular weight of a chain and
is the number of chains of that molecular weight
Mn can be predicted by polymerization mechanism and is
measured by methods that determine the number of molecules in
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9. Weight average molecular Weight(mW
The weight average molecular weight is defined by :
Mw= ∑Ni Mi2/ ∑Ni Mi
Where, Mi- is the molecular weight of a chain and
Ni- is the number of chains of that molecular
weight
Compared to Mn ,Mw takes in to account the
molecular weight of chain in determining
contributions to the molecular weight average.
The more massive the chain, the chain contributes to
Mw, Mw is determined by methods that are sensitive
to the molecular size rather than just their number.
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Weight average molecular Weight(mW)
The weight average molecular weight is defined by :
is the molecular weight of a chain and
is the number of chains of that molecular
Compared to Mn ,Mw takes in to account the
molecular weight of chain in determining
contributions to the molecular weight average.
The more massive the chain, the chain contributes to
Mw, Mw is determined by methods that are sensitive
to the molecular size rather than just their number.
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10. HigHer AverAge MoleculAr WeigHt
In general the series of avg molecular weight can be
defined by the equation M= ∑Ni M
Where
n=1 gives M= Mw
n=2 gives M=Mz
n=3 gives M= Mz+1
For all synthetic Polydispersity polymers: Mn<Mw<
Polydispersity index(PDI) =Mw/Mn
Examples: 100-10000 average molecular weight
5000-10000
10000 mw=mn monodispersity
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HigHer AverAge MoleculAr WeigHt
In general the series of avg molecular weight can be
defined by the equation M= ∑Ni Mn+1/∑Ni Min
For all synthetic Polydispersity polymers: Mn<Mw<Mz<Mz+1
Polydispersity index(PDI) =Mw/Mn
10000 average molecular weight
monodispersity
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35. ChemiCal analysis
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Composition analysis involves the estimation
like oxygen, hydrogen, sulphur, carbon,
Ex: the technique is used to detect silicon
ChemiCal analysis
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estimation of gaseous impurities
carbon, silicates.
silicon may present in solution
38. Compressibility of metal powder
Compressibility and compactable
describe the extent to which
densified by the application
The compressibility of a powder
factors.
1.Inherent hardness of the metal
2.Particle shape
3. Internal porosity
4. Particle size distribution
5.Presencr of non metallic
6. Use of solid lubricants
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Compressibility of metal powder
compactable are terms used to
which a mass of powder can be
application of pressure alone.
powder is influenced by several
metal or alloy
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40. Powder Pressing and comPaction
Binders: the binder is mixed with the powder to form the
feedstock. Most binder are multiple component mixtures
that contains a major ingredients which indicates the basic
properties along with additives used to obtain the other
desired properties.
Characteristic
A good binder
1. must have low inherent viscosity at the shaping
temperature
2.must be strong and rigid after shaping
3.should have low molecular Weight
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Powder Pressing and comPaction
Binders: the binder is mixed with the powder to form the
feedstock. Most binder are multiple component mixtures
that contains a major ingredients which indicates the basic
properties along with additives used to obtain the other
1. must have low inherent viscosity at the shaping
2.must be strong and rigid after shaping
3.should have low molecular Weight
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41. Powder interaction
1.Wet and adhere to the powder
2.Be chemically passive
3.Be stable during mixing and shaping
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Powder interaction
1.Wet and adhere to the powder
3.Be stable during mixing and shaping
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