Abstract: This paper will describe a powder and processing method that facilitates single presssingle
sintered densities approaching 7.5 g/cm³. At this sintered density, mechanical properties of
the powder metal (P/M) component are significantly improved over current P/M technologies and
begin to approach the performance of wrought steels. High performance gears have the added
requirement of rolling contact fatigue durability that is dependent upon localized density and
thermal processing. Combining high density processing of engineered P/M materials with
selective surface densification enables powder metal components to achieve rolling contact fatigue
durability and mechanical property performance that satisfy the performance requirements of many
high strength automotive transmission gears. Data will be presented that document P/M part
performance in comparison to conventional wrought steel grades.
Abstract: The processes of P/M affect the properties of sintered gears. The different techniques of
P/M lead to the different properties of sintered gears. This paper summarizes new progress in
powder metallurgy for sintered gears. These progresses include warm compaction, high velocity
compaction, sinter hardening, high temperature sintering, infiltration, CNC powder press and
surface densification etc.
Abstract: In this work the elastic behaviour of metallic powder compacts is studied. Cylindrical
specimens with different levels of density have been submitted to uniaxial compression tests with
loading and unloading cycles. The analysis of the elastic loadings shows a non linear elasticity
which can be mathematically represented by means of a potential law. Results are explained by
assuming that the total elastic strain is the contribution of two terms one deriving from the hertzian
deformation of the contacts among particles and another that takes into account the linear elastic
deformation of the powder skeleton. A simple model based in a one pore unit cell is presented to
support the mathematical model.
Abstract: The deformation under radial pressure of rectangular dies for metal powder compaction
has been investigated by FEM. The explored variables have been: aspect ratio of die profile, ratio
between diagonal of the profile and die height, insert and ring thickness, radius at die corners,
interference, different insert materials, i. e. conventional HSS, HSS from powders, cemented
carbide (10% Co). The analyses has ascertained the unwanted appearance of tensile normal stress
on brittle materials, also “at rest”, and even some dramatic changes of stress patterns as the die
height increases with respect to the rectangular profile dimensions. Different materials behave
differently, mainly due to difference of thermal expansion coefficients. Profile changes occur when
the dies are heated up to the temperature required for warm compaction. The deformation patterns
depend on compaction temperature and on thermal expansion coefficients.
Abstract: With the onging trend of reducing the weight of automotive parts, there is also an
increasing trend in the use of light alloys. Recently, aluminum powder metallurgy has been the
subject of great attention due to the combination of the lightweight characteristics of aluminium and
the efficient material utilisation of the powder metallurgical process, which offer attractive benefits
to potential end-users.
Conventional press and sinter route of non-ferrous P/M products are based compaction at room
temperature prior to the sintering cycle. However, warm compaction process has successfully
provided increased density in ferrous powder metallurgy parts, which contributes to better
mechanical properties and consequently overall performance of those parts. This study is aimed at
exploring the use of warm compaction process to aluminium powder metallurgy. This paper
presents a detailed study of the effect of warm compression and sintering conditions on the resultant
microstructures and mechanical properties of Al-Cu-Mg-Si PM blend.
Abstract: This study is focused on the manufacturing technique of powder injection molding of
watch case made from zirconia powder. A series of computer simulation processes were applied to
the prediction of the flow pattern in the inside of the mould and defects as weld-line. The material
properties of melted feedstock, including the PVT graph and thermal viscosity flowage properties
were measured to obtain the input data to be used in a computer simulation. Also, a molding
experiment was conducted and the results of the experiment showed a good agreement with the
simulation results for flow pattern and weld line location. On the other hand, gravity and inertia
effects have an influence on the velocity of the melt front because of the high density of ceramic
powder particles during powder injection molding in comparison with polymer’s injection molding
process. In the experiment, the position of the melt front was compared with the upper gate and
lower gate positions. The gravity and inertia effect could be confirmed in the experimental results.
Abstract: Powder Injection Molding (PIM) has recently been recognized as an advanced
manufacturing technology for low-cost mass production of metal or ceramic parts of complicated
geometry. With this regards, design technology of dental scaler tip PIM mold, which has complex
shape and a slim core pin of 0.6 mm diameter, with the help of computer-aided analysis for powder
injection molding process was developed. Computer-aided analysis for dental scaler tip mold was
implemented by finite element method with non-Newtonian fluid, modified Cross model viscosity,
PvT data of powder/binder mixture. The core deflection analysis of dental scaler tip PIM mold
during PIM filling process was also investigated. Compter-aided analysis results, such as filling
pattern, weldline formation, and air vent position prediction were investigated and eventually
showed good agreements with experimental results.
Abstract: With the capability of net shaping for complex 3D geometry, powder injection molding
(PIM) is widely used for automotive parts, electronics and medical industry. In this study, an
ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An
injection mold was designed and machined to produce the dental scaler tip by the PIM process. The
mold design was aided by CAE analysis. A PIM feedstock was made of SUS316L powder and a
wax based binder. The filling balance in the mold was checked by a short shot test with LDPE and
the PIM feedstock. Production capability of the PIM process for the dental scaler tip was examined
with the mold. Although there were minor problems such as a discoloration around the gate and a
flashing at the air vent, the PIM process turned out to be an excellent substitute for machining
process to manufacture the ultrasonic dental scaler tip.
Abstract: Micro powder metal injection molding has received attention as a manufacturing
technology for microparts. Small powder size is very useful in achieving detailed structures. STS
nanopowders with an average diameter of 100 nm and STS micropowders with an average diameter
of 5 micron were utilized to produce feedstock. The mixing behavior of the feedstock was indicated
that the nanoparticle feedstock produce highest mixing torque at various powder_loading than the
micropowder feedstock. Ares rheometer was utilized to examine visco-elatic flow behavior. The
nanoparticles feedstocks showed that elastic properties are dominant in flow behavior and high
viscosity. Whereas the micropowders feedstocks, viscous properties are dominant in flow behavior
and less viscosity.
Abstract: In this present investigation, Metal Injection Moulding (MIM) of M2 High Speed Steel
(HSS) parts using a wax-High Density Polyethylene (HDPE) binder is shown. This work is focused
on the examination of the sintering densification and microstructure evolution of the parts. The
injection molding process of the feedstock has been optimized to obtain high quality green parts.
The elimination of organic binder was carried out by thermal debinding under inert atmosphere. In
order to keep carbon in the sample that could improve the sintering process, incomplete debinding
was performed between 450 and 600 °C. The specimens were sintered at temperatures between
1210 and 1280oC in high vacuum atmosphere, obtaining the 98% of the theoretical density. A
homogeneous distribution of fine M6C carbides was obtained as well as V-rich carbides (MX)
during sintering which reinforced the HSS and hence increasing the mechanical properties of the
parts. In the samples with higher residual carbon content, the sintering window was extended up to
20 degrees and the optimum temperature was lower.