Tool life of TiAlN PVD coated carbide tool in high-speed end milling of untreated inconel 718 under minimum quantity lubrication condition

This paper presents the tool life of the end milled Inconel 718, which is part of a material that is difficult to be machined. Previous researchers found that tool life in machining aged Inconel 718 is shorter compared with other materials. However, this observation required further investigation. Thus, a raw grade Inconel was proposed in this experiment. The experiments were performed using TiAlN-coated carbide. The studied milling parameters were the cutting speed, Vc, from 90 to 150 m/min; feed rate, fz, from 0.15 to 0.25 mm/rev; depth of cut, ap, from 0.3 to 0.5 mm; and radial depth of cut, ae=1 mm. The application of the cutting fluid used in this experiment was a minimum quantity lubricant, which had the advantage of cooling effectiveness and low consumption of cutting fluid. The results showed that the feed rate, fz, was the primary factor controlling the tool life. The combination of Vc=115 m/min, fz=0.15 mm/tooth, as well as ap=0.5 mm and ae=0.15 mm gave the longest tool life that served 95.38 min in operation

EFFECT OF PARAMETER CONDITION ON SURFACE ROUGHNESS FOR MACHINING AISI D2 HARDENED TOOL STEEL

Hardened steel such as AISI D2 is often used in mould and die industry. Some of the application required to have good surface quality profile and sophisticated free-form shape simultaneously. In current industry practice, manual polishing and grinding is often performed to achieve the required machining tolerance which tends to lower the productivity and difficulty in ensuring the component accuracy. Machining surface roughness is directly affected by the milling parameter and should be methodically analyzed. Thus, this paper aims to study the effect of milling parameter on surface roughness of AISI D2 tool steel. Response Surface Methodology (RSM) technique was used to evaluate the influence of milling parameter namely cutting speed, feed rate and depth of cut on machined surface. From the conducted study, based on the statistical analysis result it is found that feed rate is the main factor that influence the surface roughness followed by milling speed and depth of cut. In addition, the machined surface roughness observed was between 1.5 to 4.5 μm Ra

Optimization of Drill Geometry Design to Minimize Thermal Necrosis in Surgical Bone Drilling

During the orthopedic bone drilling surgery procedures, the friction between the drill and bones surface leads to a localized temperature increase results in thermal necrosis on the soft tissue surrounding the hole. The magnitudes of the friction energy are greatly dependent with the drill geometry design. Recognizing the importance on studying this phenomenon, this paper aim to investigate the effects of drill geometry on temperatures during the bone drilling procedure. Totals of 17 drills were design and tested with different geometry namely point angle, helix angle and web thickness on different penetration angle (0⁰, 15⁰, and 30⁰) to mimic the manually control penetration by the surgeon. From the conducted investigation, the most significant parameter that affects the temperature rise was the penetration angle followed by the point angle. In addition, the interaction between helix angle and web thickness also controlled the drilling temperature. From the result, the optimum drill-bit design geometry was 21.8% web thickness, 126.92° point angle and 36.53° helix angle which produces the minimum drilling temperature

A PROPOSAL OF MUDA INDICATOR AGENT TO ESTIMATE LEAN MANUFACTURING VERIFICATION

Lean Manufacturing (LM) is the philosophy to improve productivity of manufacturing system by eliminating wastes. LM tools have been implemented as software tools in order to implement this philosophy. However, implementing LM in factories does not always succeed because of several reasons; insufficient expertise and knowledge on LM practitioners, dynamic feature of complicated manufacturing processes, difficulty in quantifying the benefits of LM implementation, and etc. Simulation-based approaches have been proposed to support LM implementation, and their effectiveness has been reported in several papers. However, they are not suitable for LM practitioners who are not familiar with simulation software. Therefore, some appropriate niche techniques to bridge the gap between LM practitioners and simulation-based approaches are expected to achieve successful LM implementation. This research proposes an agent-based approach to LM implementation using Muda Indicator (MI) agent to narrow the gap. This paper presents the overview of MI agent, defines quartile calculation to determine Muda level, explains MI indication by MI agent, and shows the feasibility of MI agent using a manufacturing process model. The feasibility study showed how MI agent presents transition of quantifying wastes during simulation in a dynamic manner

SIMULTANEOUS TWIN CUTTER TECHNIQUE FOR MACHINING THIN WALL LOW RIGIDITY PART

Machining of low rigidity components such as aerospace monolithic part poses several challenges. In common manufacturing practice, the wall thickness is further reduced by peripheral milling that lead to surface dimensional error resulting in tolerance violation. The surface errors are mainly induced by the acts of cutting force, which deflect the wall on the opposite direction. Additional post machining process are generally employ to compensate with the excessive error that leads to increase the production cost. Therefore, this paper aim to solve the discrepancies with the current techniques by using a simultaneous twin cutter machining technique. An in-house twin cutter adapter has been developed to transmit the rotation from the machine spindle. A set of machining test was performed to assess the effectiveness of the propose technique. The results indicated that the deflection of the thin wall part can be neglected and hence minimize the surface errors since the same cutting forces acts on both opposite sides of the wall surface. In addition, the proposed technique able to reduce the machining time up to 50 percent as the wall structure are machined with only one single pass

MULTI-RESPONSE OPTIMIZATION OF PLASTIC INJECTION MOULDING PROCESS USING GREY RELATIONAL ANALYSIS BASED IN TAGUCHI METHOD

This project investigates the multi-response optimization using grey relational analysis based in Taguchi method of plastic injection mould. Four input process parameters selected are mould temperature, melting temperature, injection time and cooling time. The responses investigated were part weight, shrinkage, warpage, ultimate tensile strength, tensile modulus and percentage of elongation. It is found that the optimum setting parameter generated from multi-response optimization is at run number 4 that are mould temperature at 56oC, melting temperature at 250oC, injection time at 0.7s and cooling time at 15.4s. Result of run number 4 for multi-response optimization for part weight, warpage, shrinkage, tensile ultimate strength, tensile modulus and percentage of elongation are 6.9807g, 0.087mm, 1.73%, 24.732MPa, 981.76MPa and 31.37%, respectively. Multi-response optimization results show that all response results are not higher or lower than experimental results. This is because multi-response optimization normalized all response value. Thus, by implemented multi-response optimization process, the materials characteristics value of plastic part can be predicted

Biology, Fishery, Conservation and Management of Indian Ocean Tuna Fisheries

The focus of the study is to explore the recent trend of the world tuna fishery with special reference to the Indian Ocean tuna fisheries and its conservation and sustainable management. In the Indian Ocean, tuna catches have increased rapidly from about 179959 t in 1980 to about 832246 t in 1995. They have continued to increase up to 2005; the catch that year was 1201465 t, forming about 26% of the world catch. Since 2006 onwards there has been a decline in the volume of catches and in 2008 the catch was only 913625 t. The Principal species caught in the Indian Ocean are skipjack and yellowfin. Western Indian Ocean contributed 78.2% and eastern Indian Ocean 21.8% of the total tuna production from the Indian Ocean. The Indian Ocean stock is currently overfished and IOTC has made some recommendations for management regulations aimed at sustaining the tuna stock. Fishing operations can cause ecological impacts of different types: by catches, damage of the habitat, mortalities caused by lost or discarded gear, pollution, generation of marine debris, etc. Periodic reassessment of the tuna potential is also required with adequate inputs from exploratory surveys as well as commercial landings and this may prevent any unsustainable trends in the development of the tuna fishing industry in the Indian Ocean

Internship and audit expectation gap among undergraduate students in Universiti Utara Malaysia

The accounting profession has long faced the issue of an audit expectation gap: being the gap between the quality of the profession's performance,its objectives and results, and that which the society expects.Studies have been carried out worldwide to determine the effect of education in narrowing the audit expectation gap.Extending the knowledge acquired, this paper investigates whether intership program could reduce the audit expectation gap in Malaysia.Using a pre-post method, the research instrument adapted from Ferguson el al. (2000) is administered to the UUM's accounting students before and after completing an internship program.The results show a significant change in their perceptions after the internship program.However changes in perceptions may not warrant an internship program as a means of reducing the audit expectation gap as misperceptions abaut the duties of auditors for fraud prevention and detection are still found among respondents. Nevertheless, an internship can still be used to complement audit education as it is an ideal way to expose students to professional issues and enables them to have a better insight of the actual performance and duties of auditors