Search results

Cutting Force Analysis in Micro Milling of Steel Bing Wu1,a, Huaizhong Li1,b 1School of Mechanical and Manufacturing Engineering, Faculty of Engineering, the University of New South Wales, Australia abwucap@gmail.com, bhz.li@unsw.edu.au Keywords: Micro end milling, Cutting force, Tool edge radius, Feedrate.
Chae et al. [2] surveyed many of recent works related to size effect in micro machine and suggested that large negative rake angle affects the magnitude of the cutting force.
The feature of micro milling force can be considered to be varying among different workpiece materials since the workpiece property may also play an important role associated with size effect in micro milling.
Since the uncut chip thickness is determined by the feed per tooth and tool rotation angle, it can be considered as an important factor resulting cutting force variation in each tool revolution.

Introduction Due to its good properties of high specific strength, high specific stiffness and low density, ultra-heavy plates of high-strength aluminum alloy are widely used in aerospace and weapon industries [1,2].
In order to obtain high strength property, the aluminum alloy thick plate need to be treated by solid solution and aging treatments.
And the feed of die is another important parameter that can affect stress relief of the plates [12].
Sensitivity of material properties on distortion and residual stresses during metal quenching processes.
Mechanism of superiority of fatigue strength for aluminium alloy sheets joined by mechanical clinching and self-pierce riveting.

Recent studies by means of α-spectrometry reveal a normal behaviour: activation enthalpies and pre-exponential factors similar to the self-diffusion one and diffusion coefficient values in the same order of magnitude than self-diffusion.
Creation of different types of defects in the crystal structure during irradiation, coarsening of finely dispersed precipitate in heat-resistant alloys, diffusion creep and other interactions are only a few examples of the effect of diffusion on the properties of metals and alloys.
Under these conditions, migration of atoms in the crystal lattice is one of the decisive factors leading to performance degradation.
The particular study of diffusion at infinite dilution, the determination of actual values of diffusion coefficients D at different temperatures and the diffusion parameters Q (activation enthalpy) and D0 (pre-exponential factor), brings fundamental information on properties of the various defects present in those materials.
Both metals are in the same column of the periodic table and share an electronic structure combining unpaired d and s valence electrons and several thermodynamic properties.

This deformation induced martensitic transformation provides a composite strengthening effect, and combined with the dislocation densification it produces a high strain hardening and good mechanical properties.
The different elastic and plastic properties of the phases in this potentially three-phase material will respond dissimilarly during loading and residual stress partitioning between the three phases will be generated.
Tensile samples for in situ experiments were cut from cold rolled sheets by pulsed Nd-YAG laser to ensure a low heat input and unaffected material properties.
The results are not as clear in the transverse direction, since the measured strains are much lower and therefore more significantly affected by the error margins.
Plastic anisotropy is also a factor to consider and it involves the number of operational slip systems.

In addition, the use of Portland Cement (PC) in normal concrete will affect the environment.
There was no study concerning the effect of steamed curing on properties change of geopolymer.
From Fig.5, it is clear that the correlation between the porosity and density of specimens either for normal curing or steamed curing had approximately the same value, therefore the curing factor did not affect that relationship.
Rangan, “Development and Properties of Low-Calcium Fly Ash-Based Geopolymer Concrete”, in Research Report GC1, Perth, Australia: Faculty of Engineering, Curtin University of Technology. (2005) [4] J.Davidovits, Geopolymer Chemistry & Applications, 2nd edition, Publish by Institut Geopolymer 16 rue Galilee F-02100 Saint – Quentin, France. (2008) [5] S.E.
“Mechanical Properties of MIRHA-Fly ash Geopolymer Concrete”.

It has been found that Nb is the essential and effective element improving the mechanical and corrosion resistant properties of TiAl based alloy [8].
The corrosion behavior in various environments is a limiting factor for the lifetime.
The study of corrosion resistance of TiAl based alloys in acids and alkalis, makes it possible to predict their service properties in these media.
It is apparent that the pore parameters are not affected by different Nb additions.
Chen, Pore structures and thermal insulating properties of high Nb containing TiAl porous alloys, J Alloy Compd. 492(2010) 213-218

Introduction Generally, the ablation process is coupled with denudation and air flushing, which severely affects the roughness degree and the outline of the ablator.
Furthermore, the ablation products and denudated particles depart from the aircraft surface and react with the ionizing and dissociating air, which may affect the wake flow and its photoelectric characters.
Furthermore, as a result of the gas flushing and the degradation in mechanical property, the inner cracks grow till part of the material fails, which may be washed away from the specimen; the denudated blocks enter the wake and keep ablating in Fig. 1 (c).
(4) where ch denotes thermochemical mechanism, w denotes wall surface, (),i wP is the surface pressure resulted by i component, (),ˆ i wρ is the surface concentration of i component, ()ch im� is the newly generated mass of i component in a unit volume per unit time, eP is the pressure outside the boundary layer, R is the mole gas constant and wT is the wall temperature, wgM , denotes the mean molecular weight， iE and iK are an activation energy and a frequency factor between C and i component.

Introduction Residual stress is an important factor which affect the processing precision and stability of thin-wall work pieces, residual stress, on the other hand, is directly affected by cutting parameters, in order to reduce residual stress and improve productive efficiency at the same time, it’s necessary to build the residual stress prediction model, and optimize cutting parameters under the bound condition of residual stress, in order to get the highest productive efficiency.
Fig2 Adaptability variation curve under-115MPa Fig3 Adaptability variation curve under -125MPa Conclusions 1.This paper adopt genetic algorithm in regression analysis, built residual stress prediction model and got remarkable regression property.
Mechanical Science and Technology for Aerospace Engineering, In Chinese, 2012, 4: 633~639 [5] Michalewicz Z, Nazhiyath G.

Introduction Poly(ethylene terephthalate) (PET) is a semi-crystalline polymer and has been extensively used in synthetic fibers and plastics industry due to its excellent spinnability, mechanical properties, heat and chemical resistance, etc.
According to theory of polymer crystallization, the crystallization rate is controlled by two factors: one is free energy by polymer nucleation (related to nuclei formation rate) and the other is activation energy required when polymer chains diffuse to crystallization interface(related to crystal growth rate).
On the other hand, the presence of CB would affect the movement of molecular chains, hinder their access to the lattice and depress the crystallization ability of PET, which are not conducive to PET crystallization.
This is a pair of contradictory factors and the final crystallinity is the competition result of the two factors.
When relative crystallinity is equipotent, the F(T) of PET is greater than that of PET/CB composite, which reveals that CB affects the mechanism of nucleation and crystal growth of PET and accelerates the crystallization rate of PET, in agreement of results of Avrami equation.

The efficacy of this approach was evaluated in terms of encapsulation efficiency (EE), drug loading content (DLC), delivery properties and cytotoxicity in vitro.
The MEL magnetic microspheres showed good EE values, between 60.6% and 75.6%, as well as good DLC values, between 16.7% and 32.2%, and the magnetic properties were not significantly affected by incorporation of the drug.
The physicochemical properties of this material can be suitably modulated.
The effective use of magnetic Fe3O4 nanoparticles for biomedical applications, such as targeted drug delivery, depends on a number of factors related to the size and magnetism of the biocompatible nanoparticles.
Magnetic properties.