Introduction
Prototypes
is use for many reason. One of important reason is we can use it or to know it
physically before we are going to produce it in mass production.
One problem is : if we make a prototype
with unique and complicated (artistic) by using CNC, or Conventional Machine is
need more time and much money. So in that reason we can use Rapid Prototype
(RP).
Background
RP
can be reduce cost about 70% and time 90 % (Waterman, N., and P. Dickens,
1994). Many way of RP can be done such as :
Laminated
Object Manufacture (LOM)
Selective
Laser Sintering (SLS)
Ink
Jet Printing (IJP)
Fused
Deposition Modeling
(FDM)
Stereo
Lithography (SL)
In
1980’s Powder metallurgy is grow up in manufacturing.(German et. al.)
There
are three technique for doing this field :
a. Metal
injection
molding (MIM);
b. Powder
injection
molding (PIM);
c. Slurry
casting
(SC).
Metal
injection molding begins by taking a fine metal powder, or combination of, and
mixing it with a binder. Polymers and waxes are commonly used, in small
quantities, to form and feedstock that can then be shaped through injection
molding under high pressure(German et. al.; Liu, Z., et.al.).
Powder
injection
molding (PIM) is similar to MIM. The reason it is not included
under the
same definition is because it also may involve ceramics.
(German, R. M.2011 , German, et.al. 1997, Randall M. et.al. 2005)
Slurry casting is a technique employing wax
molds to cast slurries of either metal or ceramic powders.
The molds are usually produced using technique called Mold Shape
Deposition Manufacturing
(MoldSDM).
Result and discussion
PEG (polyethylene
glycol) And Lanolin Mixtures
Prior to mixing a feedstock, 2.04g of PEG and
1.02g of lanolin were heated on a hot plate set
to 150⁰C. Both substances melted. After agitation, both substances mixed well and
showed no
signs of separation once agitation was stopped.
Crayola
Crayon
Crayola brand
crayons were used 2 formulations. Using the same technique to mix
binders and
add powder as mentioned for previous mixtures, the solution was brought to a
temperature of
110⁰C on a 200⁰C hot plate.
Discussion
1. Use
water: To concern about feedstock temperature 200 C.
2. Use Wax (BW and CW) As
more powder was added to the
feedstock to
increase the solids loading,
ejection became a concern.
Conclusion
1.
RP can be use for making molding in fast time, however if it is use in MIM,
should be concern in feedstock and low pressure.
2.
Slurry way should be determined was that the balance
between feedstock viscosity, solids loading and debinding aptitude
require
careful formulation.
3. The
greatest success was achieved via the carbonyl iron, gas-atomized, spherical,
2μm average-particle-size
powder. When mixed with a binder based upon a 70% beeswax
and 30%
carnauba wax formulation at 110⁰C, the feedstock facilitates pouring directly
into a
RP mold
heated to 85⁰C.
Recommendation
of future work should include the following:
—Alteration
of
feedstock through the direct addition of carbon
—Alloying
of
feedstock with nickel, cobalt, or molybdenum in addition to the
further exploration
of different metals such as tungsten, brass, stainless steels,
and copper.
—Experiment
with
additional waxes to reduce the temperature required to pour
the feedstock
and debind the
feedstock thereby optimizing time from conceptto-part.
—Sintering
with
the addition of a carbon-rich or nitrogen atmosphere for
improved strength.
—Heat treatment
—Debinding in a
modified kiln with the addition of an nitrogen atmosphere.
1. Waterman, N.,
and P. Dickens. "Rapid product development in the USA, Europe and
Japan."
World Class Design to Manufacture 1, no.
3 (1994): 27-36.
2.
German,
Randall M., and Animesh
Bose. Injection Molding of Metals and Ceramics.
New
Jersey:
Metal Powders Industries Federation, 1997.
3.
German,
R. M. Powder Injection Molding. Unpublished Course Material, San Diego:
San Diego
State University, 2011
4.
Liu,
Z., N. Loh, S.
Tor, and K. Khor.
"Characterization of Powder Injection Molding Feedstock."
Materials Characterization 49, issue 2-3
(2003): 313-320. doi: 10.1016/S0167-577X(00)00151-8.
5.
Randall
M. German. Powdered Metallurgy & Particulate
Materials Processing. New Jersey: Metal Powders Industries Federation,
2005.
6.
Youtube,
2012, about MIM
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