Applied Mechanics and Materials Vol. 404

Abstract: In this paper, the cutting performance of cemented carbide with ultrafine particles using single crystal diamond for tool material in die and mold manufacturing is investigated. The flat work is done using spiral for tool pass. The flat work is divided into small area and middle area. The spiral pitch in addition to depth of cut is changed in flat work. The tool wear is also estimated from form deviation by measuring surface form before and after machining. These results showed that ductile mode cutting was possible and the tool wear could be estimated from surface form. The tool wear was large in proportion to both the depth of cut and cutting length.

Abstract: This paper reports the factors that affect the bump height in electroless nickel immersion gold (ENIG) and their interrelation between each other. Bump height is a critical issue that needs to be investigated because a certain quality and requirements of bump height needs to be achieved prior to reflow oven soldering process. A total of four controllable process variables, with 16 sets of experiments were studied using a systematically designed design of experiment (DOE). The result suggests that the electroless nickel bath time has the most significant effect on the formation on bump height and consequently provide larger area for conductivity.

Abstract: Reactive Ion Etch (RIE) has been an important process in the world of microelectronic fabrication. Focus of this preliminary study is on how RIE affects the grain size of aluminum film which is fabricated on substrates. RIE parameters are varied to obtain 16 different recipes which are done using Design of Experiment. Grain size of the samples is recorded for all 16 samples before and after RIE treatment. This produces results that can be compared to obtain the effect of RIE on the aluminum film. Results show that RIE affects the mean grain size of the aluminum film as it increases after RIE treatment.

Abstract: Ball Grid Array (BGA) is a type of semiconductor interconnection used in Integrated Circuit (IC) which is being scaled down to micro and nanosize. The reliability of BGA in IC becomes a concern as the size of IC reduces. Hence, this leads to the study of stress on the BGA. This paper discussed the load effects of varying shear speed analysis on the BGA. A Pb-free material, Sn-3.9Ag-0.6Cu solder was applied in the simulation. Shear height value is fixed while the shear speed is varied to investigate the dynamic stress on a BGA package using Ansys software. The results from the graph plotted showed that higher shear speed results to higher shear force.

Abstract: The effects of chemical bath time in response to the bump height in electroless nickel immersion gold (ENIG) process was investigated. This paper presents the correlation between electroless process time, immersion gold process time and the bump height. A certain bump height need to be achieved in order to create acceptable solder bumps for reflow process. The study was done using a full factorial design of experiment (DOE). The DOE matrix is made of two levels with two factors. Analysis was done by plotting the main effects plot for each factor. The results suggest that higher process time increases the plating rate where the temperature fixed at 70 °C. Electroless nickel time has more influence to the bump height compared to immersion gold time.

Abstract: The foundation of the cutting process rests in the full plastic deformation of the separated material (in the form of chips) at TW, for defined conditions and a defined technological M-F system. Although the cost of the cutting tool makes up only part of the total cost for producing one component piece (8 % to 12 %), they have a significant impact particularly on the following: cutting process TW, machine stand time, number of required operations, period for which the components must stay within the company and number of cutting tools. The basic hypothesis of this article focuses on the study changes in the tool wear during drilling of a new Cast Iron GTW 35-04. The problem of drilling holes with diameter D=4 to 12 mm resides in the fact that 25 to 30% of these holes do not comply with prescribed requested requirements. This article presents the results of experiments focusing on the study of the damage process in helical drills with diameter d=8.0 mm when drilling into a new Cast Iron GTW 35-04. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters.

Abstract: The problem of drilling holes with diameter D=2 to 8 mm resides in the fact that 35 to 40% of these holes do not comply with prescribed requested requirements. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters. The basic hypothesis of this article focuses on the study changes in mechanical properties of cast iron GTW 35-04 under surface finish when drilling. The problem of drilling holes with diameter D=2 to 8 mm resides in the fact that 20 to 25% of these holes do not comply with prescribed requested requirements, [, [. This article presents the results of experiments focusing on the study of the damage process in helical drills with diameter d=5.5 mm when drilling into cast iron GTW 35-04. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters. Experimental results were verified in the production of holes in products for the computers.

Abstract: WCAl₂O₃-Carbon nanotubes (CNTs) composites were prepared by hot pressing process. Effects of trace amount of CNTs additives on the microstructure and mechanical properties of the WCAl₂O₃ were investigated. The microstructure, phase identification and hardness of composites were analyzed by using optical microscopy, X-ray diffraction (XRD) and Vickers indenter. The experimental results indicate that both the WCAl₂O₃ doped with 0.1wt% CNTs and 0.5wt%CNTs possessed the refined microstructure and enhanced mechanical properties compared with that of the WCAl₂O₃ doped with 1wt% and 1.5wt% CNTs. When CNTs were added to the WC-Al₂O₃ composites, the decarburization suppression could be achieved in the WC-Al₂O₃ powders system.

Abstract: Nanofibers produced by electrospinning represent a new class of promising scaffolds to support nerve regeneration. Here, we found that the blended solutions of chitosan (CS) with Poly (vinyl alcohol) (PVA) are appropriate for electrospinning when they form conductive, unstructured fluids displaying plasticity, rather than elasticity, in the bulk and at the interface. We then studied that utilize electrospun nanofibers to manipulate biological processes relevant to nervous tissue regeneration, including stem cell differentiation, guidance of neurite extension, and peripheral nerve injury treatments. The main objective of this article is to provide valuable methods for investigating the mechanisms of neurite growth on novel nanofibrous scaffolds and optimization of the nanofiber scaffolds and conduits for repairing peripheral nerve injuries.

Abstract: This paper investigates the effects of path controlled grinding on the grinding performance of 40Cr using vitrified-bonded cubic boron nitride (CBN) abrasive at low revolution. The evaluation of surface roughness and surface residual stress are presented. Experiments were carried out for path controlled cylindrical grinder in a wide range of grinding conditions. It can be obtained that the variation is slight in agreement with the small difference about roughness. The wheel speed and depth of cut are two key parameters to the surface residual stresses, and work speed does not seem to influence the residual stresses in the test conditions. The high residual grinding stresses of pin bearing resulting from path controlled grinding are compressive type at the surface for all conditions.