Optimization of Tool Geometric Parameters For a Small Fluteless Forming Tap (FFT)

A small blind internal thread (SBIT) is used to firmly fasten some functional components to the cover of 3C electronic products. The small internal thread is made in a blind hole using a fluteless forming tap (FFT) that does not produce chips. However, the four geometric parameters (tool width (W), tooth root diameter (D2), front-end diameter (Df) and tooth angle (θ)) for the FFT affect the thread filling rate (f) and the minimum torque (T) for the tapping process. This study reports a Box-Behnken design (BBD) using DEFORM-3D (finite element model) and MINITAB (regression analysis) software to tap 7075-T6 aluminum alloy using a small FFT to achieve a repeatable thread filling rate and minimum torque. The experimental results show that the BBD accurately predicts and simulate the thread filling rate for tapping 7075-T6 aluminum alloy. The modelling software and the experimental design for this study can be used to optimize the design of tools that are used in industrial production.

Optimum Switching Angles Control of SRM for Electric Vehicle Applications

Switched Reluctance Motor (SRM) drive is being gradually used in industrial applications, including electric vehicles (EVs), due to several advantages over conventional motors. However, the nonlinear magnetic characteristics of the motor make its controller very complicated. This paper presents a simplified procedure to obtain the optimal switching angles under hysteresis current control SRM drive over a wide range of speeds. A multi-objective optimization technique is applied to determine the optimal switch on and switch off angles that achieve the optimum combination of maximum average torque with minimum torque ripple and copper loss. A searching algorithm is developed for each operating point to define the maximum average torque and the minimum torque ripple and copper losses, as they vary for different currents and motor speeds. Then the optimal values of switching angles are stored in the lookup tables to build a MATLAB model of the SRM drive system. Finally, simulation and experimental results are presented to show the validity and effectiveness of the proposed controller.

Pengaruh Oleamida Terhadap Karakteristik Pematangan Karet Alam Terisi Silika

The purpose of this study was as a feasibility study of the utilization of oleamide as a new additive for natural rubber (NR) filled with silica using the semi-efficient vulcanization system. Silica fillers used as much as 30 parts per hundred parts rubber (phr). Oleamide was obtained from the synthesis of oleic acid with urea. Oleamide was inserted into the silica filled NR compounds with the varied composition of 0.0 phr; 2.0 phr; 4.0 phr; 6.0 phr, and 8.0 phr. The influence of oleamide on the curing characteristic of the silica filled NR compounds was observed. It was obtained that the oleamide functions as a curative and also a plasticizer. The greater the levels of oleamide added, the shorter the scorch time and optimum curing time were. Oleamide also decreased the minimum torque with addition up to 8.0 phr. The greater the levels of oleamide was, the lower the minimum torque was. Oleamide also increased the maximum torque and torque difference of the silica-filled NR composites at the addition of 2.0 phr. The 2.0 phr was the optimum composition of the oleamide.

Design of Outer-Rotor Permanent-Magnet-Assisted Synchronous Reluctance Motor for Electric Vehicles

Today’s automotive industry has focused its studies on electric vehicles (EVs) or hybrid electric vehicles (HEVs) rather than gasoline-powered vehicles. For this reason, more investment has been made in electric motors with high efficiency, high torque density, and high-power factor to be used in both EVs and HEVs. In this study, an outer-rotor permanent-magnet-assisted synchronous reluctance motor (PMaSynRM) with a new rotor topology was designed for use in an EV. The design has a transversally laminated anisotropic (TLA) rotor structure. In addition, neodymium-iron-boron (NdFeB) magnets were used in rotor topology. The stator slots were designed as distributed windings, so torque ripples are minimized. At the same time, the maximum electromagnetic torque was achieved. The analysis of the designed motor was carried out using the finite element method (FEM). Optimal values of motor parameters were obtained by improving the rotor geometry of the three-phase PMaSynRM in order to obtain maximum torque and minimum torque ripple in the design. The motor is in a 48/8 slot/pole combination, a speed of 750 rpm and a power of 1 kW. The simulation results showed that the design achieved maximum torque and minimum torque ripple.

Perhitungan Nilai Maksimum Thrust, Torque, dan Efficiency Propeller Tipe B-4 Series pada Kapal Tugboat dengan Modifikasi Diameter, Rake, dan Pitch menggunakan Metode Komputasi

ABSTRAKKapal tugboat digunakan untuk membantu kapal yang akan masuk atau keluar pelabuhan. Untuk mendorong dan menarik kapal maka diperlukan propeller sebagai mesin penggerak kapal. Kinerja propeller pada kapal tugboat sangat vital dalam menunjang fungsi tugboat tersebut. Pada penelitian ini akan melakukan modifikasi pada rake, diameter, dan pitch propeller B-Series pada kapal tugboat dengan metode komputasi sehingga diperoleh nilai efficiency yang paling baik. Simulasi pada penelitian ini akan menggunakan persamaan Reynolds-Averaged Navier Stokes (RANS) dan mendiskripsikan aliran turbulen dengan menggunakan model k-ε dan k-ω. Hasil nilai torque, thrust, dan efficiency yang sudah disimulasikan akan di verifikasi dengan diagram Wageningen. Wageningen adalah karakteristik propeller B-series yang sudah dipublikasikan dari hasil eksperimen. Dari hasil simulasi CFD diperoleh kesimpulan torque paling minimum terletak pada modifikasi dengan rake 0°, pitch 1,36, dan diameter 1,3 pada rpm 180 sebesar 545,68 Nm. Modifikasi model propeller pada 230 rpm menggunakan diameter 1,4 m, rake 5° dan pitch 1,56 merupakan modifikasi yang direkomendasikan untuk memperoleh nilai thrust maksimum sebesar 12076 N, torque 3252,5 Nm dan mendapatkan nilai efisiensi yang paling optimum sebesar 0,7443.Kata kunci: Kapal Tugboat, Propeller, Diameter, Pitch, Rake ABSTRACTTugboat is used to pull or push ships which will enter or leave the harbor. To push and pull the ship, a propeller is needed as the ship propulsion. The performance of the propeller on the tugboat is vital for supporting the function of the tugboat. This research will make modifications to the rake, diameter, and pitch of the B-Series propeller on a tugboat using computational methods in order to achieve the best efficiency values. This simulation on this research will make use of Reynold-Averaged Navier Stokes (RANS) equation and describe the turbulent flow using the k-ε and k-ω. The results of the value torque, thrust, and efficiency that have been simulated will be verified with Wageningan diagram. Wageningen is the characteristics of the B-series propeller that have been published from the experimental results. From the CFD simulation result, it is concluded that the minimum torque is showed in the modification with a rake of 0°, a pitch of 1.36 and a diameter of 1.3 m at 180 rpm which is 545,68 Nm. Modification of the propeller model 230 rpm using a diameter of 1.4 m, 5° rake and a pitch of 1.56 is the recommended modification to obtain a maximum thrust value of 12076 N, torque of 3252.5 Nm and getting the most optimum efficiency value of 0.7443.Keywords: Tugboat, Propeller, Diameter, Pitch, Rake