Advanced Manufacturing of an Aircraft Component (Fish-Head): A Technology Review on the Fabrication

The Airbus fish-head is machined using a 5-axis Computerized Numerical Control (CNC) milling machine, which consists of many complex shapes that are built into it. A conventional CNC machining requires tremendous effort in programming and investment due to the increasing in features complexity of the fish-head to be machined. An alternative method through advanced manufacturing processes namely vacuum casting, Fused Deposition Modelling (FDM) and three dimensional printing (3DP) is reviewed. The fish-head prototypes are manufactured through the concept of reverse engineering and rapid prototyping. The fish-head master pattern is digitized using a three dimensional laser scanner and edited using a surface modelling software to generate the Standard Triangulation Language (STL), which is common to most rapid prototyping (RP) machines. The fish-head prototypes are fabricated through FDM and 3DP using the STL data files, whereas the master pattern is used to fabricated silicone mould for vacuum casting. The quality of the prototypes is accessed in terms of dimensional accuracy and time to produce a single prototype. The dimensional accuracy is analysed using coordinate measuring machine (CMM). The dimensional accuracy error is found to be less than 5%. However, all prototypes require secondary surface treatment processing in order to achieve the desired surface roughness quality. All three prototypes can be manufactured less than 24 hours per prototype. The advanced manufacturing processes allows parts to be fabricated similar to parts manufactured through CNC but at a lower cost and faster

Reason Maintenance in Product Modelling via Open Source CAD System

The present and future challenges of a new product design, forecasting and risk management launch strategy for a new product modelling decision process. This paper intends to propose and to look towards the development of a low-cost integrated CAD-CAPP-CAD/CAM product modelling system for the design and manufacture of a proposed product. It is a mapping between several design phases like functional design, technical design and physical design. The modelling data generation process begins with the drafting of a product to be maintained using the drafting software package. From the CAD drawing, the data are transferred to be used as the product models and a CAPP software package will then prepare the operational parameters for the manufacturing of the product. These process data are relayed to a CAM software package, which will then generate the automating information-processing functions. The final stage of the function is to support design and manufacturing operations that may have reaped many benefits in terms of its initial equipment and software costs

Current Research Trends in Wire Electrical Discharge Machining (WEDM): A Review

Wire Electrical Discharge Machine (WEDM), a non-traditional machining process, is becoming more important in providing a non-contact machining process. It is suitable for machining geometrically complex and hard advanced material which is impossible to machine using the conventional machine. This paper reviewed the experimental results on performance evaluation of machining parameters which affected machining performance which would reflect the machining factors and responses. In addition, the methods in analyzing, modelling, development and tool steel in WEDM were also discussed. Some recommendations and future WEDM research were proposed

Reason Maintenance in Product Modelling via Open Source CAD System

The present and future challenges of a new product design, forecasting and risk management launch strategy for a new product modelling decision process. This paper intends to propose and to look towards the development of a low-cost integrated CAD-CAPP-CAD/CAM product modelling system for the design and manufacture of a proposed product. It is a mapping between several design phases like functional design, technical design and physical design. The modelling data generation process begins with the drafting of a product to be maintained using the drafting software package. From the CAD drawing, the data are transferred to be used as the product models and a CAPP software package will then prepare the operational parameters for the manufacturing of the product. These process data are relayed to a CAM software package, which will then generate the automating information processing functions. The final stage of the function is to support design and manufacturing operations that may have reaped many benefits in terms of its initial equipment and software costs

SUPPRESSION OF CUTTING FORCES USING COMBINED INVERSE MODEL BASED DISTURBANCE OBSERVER AND DISTURBANCE FORCE OBSERVER

This paper focuses on damping strategies that addressed the effect that high frequency harmonics content of cutting force have on positioning accuracy of the x-axis of an XY positioning table via controller and observer design approaches. Cutting force generated from direct contact between the workpiece and cutting tool becomes input disturbance to the drive system of the positioning table. The force high frequency components if left undamped would generate vibration to the system thus affecting the system positioning accuracy, surface finish quality as well as tool life. For this purpose, a cascade P/PI position controller, an Inverse Model Based Disturbance Observer (IMBDO) and a Disturbance Force Observer (DFO) were designed and numerically analysed. The cascade P/PI controller was designed using traditional loop shaping frequency domain method. IMBDO estimates the input disturbance and any unmodelled system dynamics while DFO performs direct estimation of the cutting force using knowledge of harmonic frequencies corresponding to the input cutting force. A combined cascade P/PI controller with IMBDO and DFO reduced additional 3.83% and  1.90% tracking errors compared to separate application of IMBDO and DFO. This novel control approach produced between 34-80% greater reductions in peak amplitudes of the harmonics content of the cutting forces compared to cascade P/PI

Prediction of Cutting Force in End Milling of Inconel 718

This paper presents the effect of cutting parameters on the cutting force when machining Inconel 718. Response surface methodology (RSM) was used in the experiment, and a Box–Behnken design was employed to identify the cause and effect of the relationship between the four cutting parameters (cutting speed, feed rate, depth of cut and width of cut) and cutting force. The ball-nose type of end mill with donwmill approach was maitained througout the experiment. The forces were measured using Kistler dynamometer during straight line machining strategy. The result shows that the radial depth of cut was the dominating factor controlling cutting force, it was followed by axial depth of cut and feed rate. The prediction cutting force model was developed with the average error between the predicted and actual cutting force was less than 3

Executive cash compensation and tax aggressiveness of Chinese firms

We examine the influence of corporate compensation policies on firms’ tax aggressiveness in an emerging market where executive compensation is primarily in cash form. Based on a hand-collected dataset of 958 firm-year observations of Chinese listed firms for the 2006-2012 period, we find that firms paying higher executive cash compensation are associated with lower tax aggressiveness. This relationship also holds for the excess cash compensation measures which control for executive shareholding, firm profitability, size, growth opportunity, and board independence. We further document that mutual funds ownership pressure firms paying higher compensation to reduce their tax aggressiveness, suggesting adverse selection by mutual funds on firms exhibiting risky tax avoidance activities. High leverage offsets the negative link between cash compensation and tax aggressiveness, indicating a complementary effect between debt and tax avoidance, and, hence, suggesting that creditor monitoring is weak. These results are robust to the system-GMM estimation, which simultaneously account for the endogeneity of executive compensation, tax aggressiveness, ownership and control, leverage, and corporate governance. Our findings on Chinese firms have important policy implications for developing countries around the world with concentrated ownership structure, weak institutional environment, widespread corruption, ineffective rule of law, and ongoing significant social and political transformation

Corporate governance in the Islamic finance industry

No abstract available

Islamic finance: risk sharing as sustainable risk management

No abstract available