Prevention of Springback of High Strength Steel Sheet in L-Bending Process

Nowadays steel sheets are widely used in the industry due to the advantages of this materials in offering high strength with light weight. However due to the high tensile strength the manufacturing process need an improvement to overcome the defects occurred in the production. Therefore, a proper method is required in order to prevent the defects. In this study, a dies set with chamfers are developed to substitute the large radius that are used in current bending process. Bending process were conducted for high strength steel sheets with tensile strength of 780 MPa; to test the effectiveness of the developed die. By using this die, the chamfers enable smaller bending radius to substitute the large radius that cause the springback. It was found that the small radius produces by the chamfers are more effective in reducing the springback in L-bending of high strength steel sheets and the high press-speed will also contribute to the reducing of the springback

In-Situ Measurement of Electrode Wear During EDM Drilling using Vision System

Machine vision system is an image-based technology used to perform automatic inspection and analysis such as process control and robot guidance. The aim for this project is to develop a fully automated electrode wear detection system in EDM by using machine vision system and apply this system in detecting electrode wear in EDM. This project was conducted using DSLR camera as monitoring device. The electrode undergo hole making process with a depth of 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm to observe the electrode condition. The image of the electrode will be remotely captured from the laptop and then will undergo image processing process using Matlab software to calculate and determine the electrode wear. The output of this project will show the images of the electrode wear and its wear value. Findings from the project showed that this system is suitable and applicable in EDM super drill machine to monitor the tool condition

Lean management in quality improvement of cutting and hot forming process for window tint

The objective of this study is to describe the application of the DMAIC (Define, Measure, Analyze, Improve, and Control) technique at a Malaysian company that forms and cuts window tint film. This case research focuses on the Define, Measure, Analyze, Improve, and Control (DMAIC) phases for a full and effective project implementation and presentation. According to the findings of this case study, dust is a significant flaw in the cutting process. It was also discovered that the upgrades initiative directly benefits others, including economic benefits. The application of this powerful tool has not only reduced the rate of defects, but also in the areas of product development, customer retention analysis, cycle time optimization, productivity improvement and market share

Hemming for Joining High Strength Steel Sheets

AbstractA high strength steel sheet is used to make the hollow sections for the body structure of automobiles. The hollow sections, which are typically joined by resistance spot welding have insufficient energy absorption because the joins are not continuous. Thus, to overcome this problem, the hollow section is joined using the hemming process. The hemming of the high strength steel sheet was successfully performed using punch with stopper. The high strength steel hollow sections joined by hemming and resistance spot welding were then examined by tensile and fatigue tests. The hollow section with hemmed joins showed better performance in both tests. The overlapping joins of the hemmed hollow section have greater strength as compared to the resistance of spot welding joins

Performance analysis of abrasive waterjet machining process at low pressure

Normally, a commercial waterjet cutting machine can generate water pressure up to 600 MPa. This range of pressure is used to machine a wide variety of materials. Hence, the price of waterjet cutting machine is expensive. Therefore, there is a need to develop a low cost waterjet machine in order to make the technology more accessible for the masses. Due to its low cost, such machines may only be able to generate water pressure at a much reduced rate. The present study attempts to investigate the performance of abrasive water jet machining process at low cutting pressure using self developed low cost waterjet machine. It aims to study the feasibility of machining various materials at low pressure which later can aid in further development of an effective low cost water jet machine. A total of three different materials were machined at a low pressure of 34 MPa. The materials are mild steel, aluminium alloy 6061 and plastics Delrin®. Furthermore, a traverse rate was varied between 1 to 3 mm/min. The study on cutting performance at low pressure for different materials was conducted in terms of depth penetration, kerf taper ratio and surface roughness. It was found that all samples were able to be machined at low cutting pressure with varied qualities. Also, the depth of penetration decreases with an increase in the traverse rate. Meanwhile, the surface roughness and kerf taper ratio increase with an increase in the traverse rate. It can be concluded that a low cost waterjet machine with a much reduced rate of water pressure can be successfully used for machining certain materials with acceptable qualities

Competing risk models in reliability systems, an Exponential distribution model with Gamma prior distribution, a Bayesian analysis approach

This paper is a second paper on the use of Exponential distribution in competing risk problems. The difference is this model is developed using Gamma distribution as its prior distribution. For the cases where the failure data together with their causes of failure are simply quantitatively inadequate, time consuming and expensive to perform the life tests, especially in engineering areas, Bayesian analysis approach is used. This model is limited for independent causes of failure. In this paper our effort is to introduce the basic notions that constitute an exponential competing risks model in reliability using Bayesian analysis approach and presenting their analytic methods. Once the model has been develop through the system likelihood function and individual posterior distributions then the parameter of estimates are derived. The results are the estimations of the failure rate of individual risk, the MTTF of individual and system risks, and the reliability estimations of the individual and of the system of the model

Investigation on the Effect of Machining Parameters on Mechanical Properties of Friction Stir Processed Mg–Al-Micro Al2O3 Metal Matrix Composites

Low density of magnesium makes it an ideal choice as it is lighter than steel and aluminium alloys. Combination of cast magnesium alloys component can be used widely in the automobile sector and factories but were restricted. Friction stir processing is an infinite machining operation used to enhance the structural workpiece in solid-state strengthening. By using a straight cylindrical tool pin profile which will be used throughout this study, the effects of FSP parameters on magnesium AZ91A can be investigated. Variation of feed rates, (10–58) mm/min with a fixed rotational speed, 1208 RPM were applied for each single FSP pass. Mg alloy will be plated with Al6061 sheets and reinforced with Al2O3 particles before running FSP. Mechanical properties and metallographic requirements are the characterizations in investigating the effects of machining parameters of FSPed workpiece. Both characterizations can be gained via Rockwell hardness test and optical microscopy. Finally, this study discovered that the average hardness of FSPed Mg–Al-Micro Al2O3 was reduced significantly with the increment of feed rates. Next, improved hardness at HAZ points as well as reduced surface roughness at three distances from FSP starting point were detected

Non-vibrate palm oil tree harvesting cutter using DC motor

Long exposure use of palm oil tree harvesting cutter powered by fuel engine can give risk of Hand Arm Vibration Syndrome (HAVS) disease, due to the transmitted vibration produced from the motorized cutter. In this paper, a new design of harvesting cutter which was powered by DC motor was proposed. Results shows that the vibration value were significantly low compare to the conventional motorized cutter; ranging between 0.04 and 0.29 m/s2

Investigation on turning operation using die sinking EDM process

Electrical discharge turning (EDT) operation produces a cylindrical component using an electrical discharge machining method. Unlike a traditional turning process, it is a non-contact operation between the tool electrode and workpiece. Therefore, the design of electrode may influence the quality of turned workpiece. The present study investigates the effect of various processing parameters in EDT namely the electrode shape, workpiece rotational speed and jump down time. The analysis was conducted in terms of the surface roughness, circularity deviation and electrode wear rate. A special jig and fixture for the turning operation was developed as to fit on the commercial die sinking EDM machine. A fractional factorial approach using Taguchi orthogonal array of L9 was utilized in the present study. It was found that both shape of electrode and workpiece rotational speed had a greater influence on the surface roughness followed by the electrode jump down time. The surface roughness increases with an increase of quantity and duration of sparks during the process due to formation of a higher amount of debris. The circularity deviation has improved with a higher sparking area and faster duration of sparks since a smaller amount of workpiece material was removed thus improving its circularity. Furthermore, the highest electrode wear rate was produced using the electrode with a curvature shape which generated wider sparking area thus experiencing more erosion

Effect of Tool Shoulder-to-Pin Diameter Ratio (D/d) on the Mechanical Properties of Friction Stir Processed Mg-Micro Al2O3 Composite

The engineering industry uses magnesium as it is a low density to lightweight ratio material and able to replace the heavier material. Friction stir processing is an applicable method to modify the structural properties of the workpiece. H13 steel tools are produced into several tool parameters with different shoulder diameters to pin diameters (D/d) ratios. A fixed machining parameter of 1040 rpm for spindle speed and 17 mm/min for traverse speed was used throughout this study. Contact between the tool and workpiece produces frictional heat that softens the material. By creating magnesium alloys into metal matrix composites (MMC), microsized aluminum oxide powder (Al2O3) was reinforced during FSP to enhance the mechanical properties of the magnesium alloy AZ91A. The aim of this study is to analyze and obtain the optimal tool parameter to process Mg-Micro Al2O3. The microstructure of FSPed Mg-Micro Al2O3 was observed using a light microscope, specifically on the grain size. The hardness test was done utilizing the Rockwell Hardness Tester to validate the changes in the hardness. The shoulder diameter of 12 mm was found to be the most suitable parameter for processing Mg-Micro Al2O3 as it produced fewer defects and finer grain size