A.B. Abdullah

Development of a low-cost modular pole climbing robot

This article reports on the design and development work on a modular pole climbing robot. Modularity was achieved by ensuring similar repeated structures can be coupled and controlled in almost similar fashion. The design considers the rudimentary aspect of climbing and adopts grasp-push-grasp motion arrangement. The resulting design consists of two grippers for grasping and two central arms for climbing and lowering, all of which employs pneumatic cylinders. The whole climbing motion was achieved in six steps and the climbing speed is determined from the rate of filling the pneumatic cylinders involved. Parallel four-bar linkages arrangement was used to ensure the horizontal orientation of the grippers to prevent locking. The structure of the robot are made from aluminum with pin joints throughout to allow for easy assembly. PLC was used at this stage for the motion control. The developed robot can climb a 150 mm diameter pole at a speed of 0.6 m/min.

An experimental investigation of springback of AA6061 aluminum alloy strip via V- bending process

Springback is one of the common geometrical defects found in the sheet metal forming process. Aluminium alloy with high content of magnesium such as AA6061 is preferred for their high formability limit, but commonly springback becomes a drawback. In this study, springback behaviour of the AA6061 will be observed. The effect of length, thickness and bend angle to the springback pattern was investigated and the result depicted that springback is more significant to thickness and bend angle, while the length gives less effect.

Geometrical Error Analysis of Cold Forged AUV Propeller Blade Using Optical Measurement Method

Accuracy is the key issue in the precision forging. Geometric and dimension errors are the two significant defects found in most of near net or net shape manufacturing process. It becomes more critical for complex part such as an AUV propeller blade. In this study, geometric error was quantified by comparing the blade profile obtained from nominal geometry of the blade and the profile constructed by commercial optical method namely Alicona system.

Precision Hole Making on Laminates Composite: Comparison between Drilling and Punching

Accurate and strong fastener assembly depends on precision of the hole. For structural material likes composites, these criteria is very important. Drilling is the most common method in producing hole on composites. But the main problem of drilling is excessive tool wear that may affect the quality of the holes. Punching is another alternative in making a hole. The main objective of this study is to compare between drilling and punching in terms of hole quality. The scanned images of the produced hole will be captured using commercial 3D optical surface measurement method namely Alicona IFM. The effect to the quality of the produced hole will be measured and compared between drilling and punching.

Measurement of Twist Springback on AA6061-T6 Aluminum Alloy Strip - A Preliminary Result

Twist forming is one of a critical process in a sheet metal forming process that has a complex profile. There are a few parameters that need to be taken into consideration, such as twist angle, workpiece geometries including length, width and thickness and material properties of the workpiece material. In this study, the preliminary result of the twist forming behavior of an aluminum alloy strip with uniform section will be studied. The experiment is conducted using torsion test machine. At this stage, the torque pattern was studied and compared with the published work to validate the experiment test rig. The result showed an agreement with the published work.

Precision hole making on laminate composite: a tool wear analysis and comparison between drilling and punching

Hole precision is highly critical for accurate and strong fastener assembly. This factor is considerably important for structural materials, such as composite materials. Drilling is the most commonly used process for producing holes on composites. However, drilling causes excessive tool wear, which may affect the quality of holes and result in damage, such as delamination. The main objective of this study is to compare the drilling and punching processes in terms of tool wear by using the focus variation technique. The scanned images of both the puncher and drill bits are obtained by using a 3D optical surface measurement device called Alicona IFM. Tool wear patterns from both drilling and punching are analysed and compared, and the effects of the processes on the quality of the produced holes are observed.

Compressive Behavior of AA6061 at Room Temperature and Validation of the FE Model Based on Optical 3D Measurement Technique

Recently, manufacturing process simulation using finite element (FE) model become important. Therefore, validation of the finite element model is crucial. This study will present validation of 2D finite element simulation of cold heading at room temperature. Validation of the simulation model is carried out by comparing the resulted bulge profile of the cold upsetting specimen to the profile of the specimen, which is obtained from an optical 3D surface measurement technique namely Infinite Focus Alicona system. Based on the result, both profiles show a very good agreement.

Modular Tooling Concept in the Fabrication of the Precision AUV Blade

Tooling plays important role in ensuring precision of cold forging part. In this study, a modular approach was proposed in the design of the tooling in the production of Autonomous Underwater Vehicle (AUV) propeller blade. Based on the conceptual design and optimization of the process sequence, the tooling was designed. As a result, the precision of the forged blade is still within the acceptable level.

Optimization of Axial Rake Angle for Face Milling Using Taguchi Method and Finite Element Analysis

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.

Geometrical Defect Evaluation of Cold Embossing AA6061 Based on FEA and Physical Modeling Technique

Geometrical defect plays a significant role to inaccuracy of the cold forging part. Defect will harm the assembly tend to affect the performance of the part. Therefore, it must be detected and minimized it as soon as the manufacturing begins. The paper presents an investigation on the geometrical defect of the cold embossing pin based FEA and physical modeling methods. The study focuses on the effect of distance to the edge (DTE) to bulging geometries. The results of both methods show a good agreement.