Applied Mechanics and Materials Vols. 465-466

Abstract: Additive Manufacturing (AM) is the direct production of finished goods using additive fabrication techniques. AM done in parallel batch production can provide a large advantage in speed and cost. Currently, the efforts to utilize AM concept and technology have several problems particularly in Malaysian automotive industry. Such existing problems have discouraged the enhancement of process and product development of automotive industry. In providing the solution, by implementing AM technology, there is potential to speed up the development of automotive parts and move towards mass customization. Several issues have been discovered by discussion with PROTON. This paper presents the critical decision factors in implementing AM in Malaysian automotive industry. Analytic hierarchy process (AHP) is used to develop the framework of decision making in order to assess the factor affecting the AM implementation. The study shows that the main factors affects the implementations of AM are financial, technological, organization and design practice. The most important aspect to be considered is the investment cost. Finally, the information presented in this paper can also assist a potential user in choosing to implement or not to implement AM technology. Keywords: Additive Manufacturing, Analytic Hierarchy Process, Automotive Industry

Abstract: The promising processing techniques of micro scale parts are very important in products miniaturization and functions enhancement. Combination of two or more processing techniques gives better processing performance especially when dealing with difficult-to-cut materials. For that reason, the combination of laser beam and micro milling process has been widely studied and proven efficient in reducing cutting force and tool life extension. However, this process needs a precise temperature control in order to eliminate heat effect generated by laser beam irradiation. In this study, temperature distributions are determined numerically to characterize the melted zone and heat affected zone geometry. From the results, the estimation of tool and micro milling cutter distance together with the allowable depth of cut are determined.

Abstract: This case study is to investigate the causes of failure of chain system through characterization on the failure component. The failures that occur are relate to welding because this dipping latex industry used customized chain that have to be weld in joining with outer chain links. The analysis revealed that the weld defect such as crater leads the crack propagation and added with cyclic loading that cause the fatigue failure. The fatigue failure occurs due to this generated crack at the outer circumference of the weld within chain attachment and outer chain links plate. This type of defect also can be categories as designing-in defect. Fatigue crack propagation was evident by progressive beach marks and the scanning electron microscopy (SEM) analysis revealed the types of microstructure that resulting at heat affected zone (HAZ). Hardness testing by using Rockwell Tester found the different hardness profile at three areas that are weld metal, base metal and heat affected zone. The maximum hardness values were found at heat affected zone and weld metal. Finite element method (FEM) that is Ansys Workbench was used to review the different size of outer link plate thickness that affected to the stress distribution. It was found that stress can be minimized with increasing the plate thickness.

Abstract: The prediction of fluctuated temperature distribution generated by pulsed wave laser in laser assisted micro milling (LAMM) is crucial. The selection of processing parameter by minimize the effect on the processing characteristic is decisive to ensure the machining quality is high. Determining the effect of heat generated in underneath surface is important to make sure that the cutting tools are able to cut the material with maximum depth of cut and minimum defects in term of tool wear and tool life. In this study the simulation was carried by using Ansys APDL. In order to confirm the actual and distribution irradiation of temperature from simulation, an experimental was done to validate the results. The experiment was conducted by using Nd:YAG laser with wavelength 1064 nm.

Abstract: The textile industry is represented not only by fashion (most popular area) but also textile material for industrial purposes. The very old use of textile materials is production of fabric bags. The deformation of such bag is the subject of computer modeling, what is the contents of the paper. The deformation of the 2D cloth layer, exposed to normal pressure, has the mathematical description in the form of the partial differential equation. The solution depends on the area, on which is searched, and on the boundary conditions. It is known only for planar circular area. The deformation of more complicated shapes (3D) must be found using computer simulations. The problem, discretized by finite element method, has the form of the system of algebraic equations. The description has non-linear character and brings a range of problems. The solution possibilities are described in the paper. Finally the solution of the 3D problem is shown.

Abstract: Assessment of process capability enables manufacturers to determine if a process produces products that meet customers expectation. Process capability can be beneficial in the long run in producing quality parts with minimum reject and optimum manufacturing cost. This paper proposes a procedure to assess process capability of a machining centers in drilling process using statistical analysis of machining parameters and machine rigidity. Experimental method used mild steel plate as work piece and carbide indexable cutting insert on drill of diameter 20mm. Cutting parameters such as cutting speed and feed rate were varied according to different cutting parameter level while wear in peripheral insert was inspected before and after each test run start. Machine rigidity in terms of vibration acceleration amplitude in x-, y-, and z-axis were measured and analyzed. Process capability index, Cpk of drilled hole accuracy was calculated. A regression model based on this experiment was established for predicting the process capability of machine tool in drilling operation. The established regression model is proven to have high accuracy, which is more than 80%. The validation test was carried out on a different machine tool with the same cutting conditions to check if different machine was adaptable to the regression model. This finding provides useful guidelines for machning operator to predict the process capability of the machine tool in the drilling process.

Abstract: This study employed the Taguchi approach in combination with finite element analysis (DEFORM3D) to investigate face milling process onto AL6061. The factors studied in this investigation were cutting speed, feed rate, and axial rake angle. The simulation of flank wear was generated according to Usuis wear model though the L₉ (3⁴) of the orthogonal array experiment. ANOVA analysis and F test were conducted to find the significant factor that contributes to tool wear in the signal to noise ratio. Finally, the confirmation test has been carried out at optimal parameter.

Abstract: There are three phases to solve multiple response optimization (MRO) problems. They are experiment design, modelling and optimization. Different committee machines (CMs) are applied for modeling of MRO problem. Two kinds of CM introduced by current authors in recent works. Initial approach includs utilization of all experts in CM and finally sequentilal combinational model (SCM) is created. Current study proposes a combinational approach to filter and select the best experts to create CM which yields optimum combinational model (OCM). Also , there was another modeling with name point approach model (PAM). This study investigated two different features of different SCMs, PAM and OCM in a famous MRO problem with name wire-bonding. This problem was defined in 1997 and then, several researchers solved it in next years. The results show PAM has minimum RMSE but its global desirability is low. Also overall RMSE has a slightly fall from SCMs to OCM , whereas, there is gently rise in global desirability from SCMs to OCM and consequently proposed approach or OCM provides superior results.

Abstract: Cholesteryl ester liquid crystals were discovered with a new application in sensing traction forces of single cells. The liquid crystal bio-transducer is produced by manual scraping of liquid crystals onto the petri dish, in which the technique is highly subjective to the skill of the user to produce homogeneously spread liquid crystal substrates. This paper describes the development of an apparatus used to produce a liquid crystal substrate using squeegee coating technique. It consists of a biaxial mechatronic system which is synchronously controlled in vertical and horizontal directions scraping the liquid crystal substrates evenly on the surface of a petri dish. The thickness of the liquid crystal was profiled using laser diffraction technique and the homogeneity of the liquid crystal films produced was examined in a crossed-polarizing microscope. At an angular speed of 1500 rpm and under a shear stress of 1.46 ± 0.72 kPa, the squeegee coating was found producing liquid crystal films at a thickness of 132 ± 23 μm on the surface of petri dishes. With the application of this apparatus, evenly spread liquid crystal coatings with control thickness in petri dishes were consistently produced. This has overcome the major problem of manually coating the liquid crystal substrates using a cell scraper.

Abstract: The paper investigates in-process signal usage in turning for indirect surface roughness measurement. Based on theoretical surface roughness value and in-process signal, a model is proposed for surface roughness evaluation. Time surface roughness and in-process signal surface roughness correlation based analysis is performed to characterize tool wear component behavior among others. Influencing parameters are grouped based on their behavior in time. Moreover, Digital Object Memory based solution and algorithm is proposed to automate indirect surface roughness measurement process.