Quality control of low-cost electric machines for electric vehicles by DOE assisted six sigma DMADV method

Author(s):  
D. M. Wu ◽  
C. K. P. Luk ◽  
W. Z. Fei
JEMAP ◽  
2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Albertus Reynaldo Kurniawan ◽  
Bayu Prestianto

Quality control becomes an important key for companies in suppressing the number of defective produced products. Six Sigma is a quality control method that aims to minimize defective products to the lowest point or achieve operational performance with a sigma value of 6 with only yielding 3.4 defective products of 1 million product. Stages of Six Sigma method starts from the DMAIC (Define, Measure, Analyze, Improve and Control) stages that help the company in improving quality and continuous improvement. Based on the results of research on baby clothes products, data in March 2018 the percentage of defective products produced reached 1.4% exceeding 1% tolerance limit, with a Sigma value of 4.14 meaning a possible defect product of 4033.39 opportunities per million products. In the pareto diagram there were 5 types of CTQ (Critical to Quality) such as oblique obras, blobor screen printing, there is a fabric / head cloth code on the final product, hollow fabric / thin fabric fiber, and dirty cloth. The factors caused quality problems such as Manpower, Materials, Environtment, and Machine. Suggestion for consideration of company improvement was continuous improvement on every existing quality problem like in Manpower factor namely improving comprehension, awareness of employees in producing quality product and improve employee's accuracy, Strength Quality Control and give break time. Materials by making the method of cutting the fabric head, the Machine by scheduling machine maintenance and the provision of needle containers at each employees desk sewing and better environtment by installing exhaust fan and renovating the production room.


2019 ◽  
Vol 1 (1) ◽  
pp. 44
Author(s):  
Rony Trizudha ◽  
Sri Rahayuningsih ◽  
Ana Komari

As technology advances at this time, players in business are aware of the importance of product quality in the increasingly fierce competition in the industrial world due to the emergence of many similar companies. Therefore, companies must be able to compete to meet customer desires and try to retain customers. To maintain customers and their marketing areas, companies must have high competitiveness in order to survive by prioritizing quality improvement, increasing efficiency and increasing productivity to improve quality because by increasing quality, products can be accepted among consumers so that company goals can be fulfilled. Therefore, the company must carry out effective quality control which will result in high productivity, lower overall cost of making goods and the factors that cause production failure to be minimized. To improve quality, use the six sigma method, DMAIC and seven tools so that it can be known the cause of the damage and what actions are taken so that there needs to be a controversy to stabilize the processes of the production process so that we can know what percentage of damage and what factors cause damage, therefore there must be measurements and recommendations for improvement and control to reduce the causes From the analysis, it was found that the dent cup was 20.36%, the lid was 21.36% less dense, the lid was damaged in the finished product 18.72%, the cup was 19.28% less thick, the packaging was flexible 20.55%Seiring kemajuan teknologi pada saat ini pelaku di bisnis menyadari akan pentingnya kualitas produk dalam persaingan dunia industri yang semakin ketat karena banyak bermunculan perusahaan-perusahaan sejenis. Oleh sebab itu perusahaan harus dapat bersaing untuk memenuhi keinginan  pelanggan dan berusaha dapat mempertahankan pelanggan. Untuk mempertahankan pelangan dan wilayah pemasaranya perusahaan-perusahaan harus mempunyai daya saing yang tinggi untuk dapat bertahan dengan mengutamakan peningkatan mutu, peningkatan efisiensi dan peningkatan produktivitas untuk meningkatkan kualitas karena dengan peningkatan kualitas, produk dapat diterima di kalangan konsumen sehingga tujuan perusahaan dapat terpenuhi. Maka dari itu perusahaan harus melakukan pengendalian kualitas yang efektif akan menghasilkan produktivitas yang tinggi, biaya pembuatan barang keseluruhan yang lebih  rendah serta  faktor-faktor yang menyebabkan kegagalan produksi akan dapat ditekan sekecil mungkin. Untuk meningkatkan kualitas mengunakan metode six sigma, DMAIC dan seven tools agar dapat diketahui penyebab  kerusakan  dan  tindakan  apa  saja  yang dilakukan sehingga perlu ada kontror untuk menstabilkan  peoses proses produksi sehinga dapat di ketahui berapa persen  kerusakan dan faktor-faktor apa saja yang menyebabkan  kerusakan maka dari itu harus ada pengukuran dan  rekomendasi perbaikan serta melakukan kontrol untuk mengurangi penyebab kerusakan. Dari hasil analisis  di ketahui cup  penyok 20,36%, lid kurang  rapat  21,36%, lid  rusak  pada produk jadi 18,72%,cup kurang tebal 19,28 %kemasan lentur 20,55%


Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 958
Author(s):  
Maosheng Zhang ◽  
Yu Bai ◽  
Shu Yang ◽  
Kuang Sheng

With the increasing integration density of power control unit (PCU) modules, more functional power converter units are integrated into a single module for applications in electric vehicles or hybrid electric vehicles (EVs/HEVs). Different types of power dies with different footprints are usually placed closely together. Due to the constraints from the placement of power dies and liquid cooling schemes, heat-flow paths from the junction to coolant are possibly inconsistent for power dies, resulting in different thermal resistance and capacitance (RC) characteristics of power dies. This presents a critical challenge for optimal liquid cooling at a low cost. In this paper, a highly integrated PCU module is developed for application in EVs/HEVs. The underlying mechanism of the inconsistent RC characteristics of power dies for the developed PCU module is revealed by experiments and simulations. It is found that the matching placement design of power dies with a heat sink structure and liquid cooler, as well as a liquid cooling scheme, can alleviate the inconsistent RC characteristics of power dies in highly integrated PCU modules. The findings in this paper provide valuable guidance for the design of highly integrated PCU modules.


2021 ◽  
Vol 7 (2) ◽  
pp. 41
Author(s):  
Farzaneh Farivar ◽  
Pei Lay Yap ◽  
Ramesh Udayashankar Karunagaran ◽  
Dusan Losic

Thermogravimetric analysis (TGA) has been recognized as a simple and reliable analytical tool for characterization of industrially manufactured graphene powders. Thermal properties of graphene are dependent on many parameters such as particle size, number of layers, defects and presence of oxygen groups to improve the reliability of this method for quality control of graphene materials, therefore it is important to explore the influence of these parameters. This paper presents a comprehensive TGA study to determine the influence of different particle size of the three key materials including graphene, graphene oxide and graphite on their thermal parameters such as carbon decomposition range and its temperature of maximum mass change rate (Tmax). Results showed that Tmax values derived from the TGA-DTG carbon combustion peaks of these materials increasing from GO (558–616 °C), to graphene (659–713 °C) and followed by graphite (841–949 °C) The Tmax values derived from their respective DTG carbon combustion peaks increased as their particle size increased (28.6–120.2 µm for GO, 7.6–73.4 for graphene and 24.2–148.8 µm for graphite). The linear relationship between the Tmax values and the particle size of graphene and their key impurities (graphite and GO) confirmed in this study endows the use of TGA technique with more confidence to evaluate bulk graphene-related materials (GRMs) at low-cost, rapid, reliable and simple diagnostic tool for improved quality control of industrially manufactured GRMs including detection of “fake” graphene.


Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.


Author(s):  
Hui Jing ◽  
Rongrong Wang ◽  
Cong Li ◽  
Jinxiang Wang

This article investigates the differential steering-based schema to control the lateral and rollover motions of the in-wheel motor-driven electric vehicles. Generated from the different torque of the front two wheels, the differential steering control schema will be activated to function the driver’s request when the regular steering system is in failure, thus avoiding dangerous consequences for in-wheel motor electric vehicles. On the contrary, when the vehicle is approaching rollover, the torque difference between the front two wheels will be decreased rapidly, resulting in failure of differential steering. Then, the vehicle rollover characteristic is also considered in the control system to enhance the efficiency of the differential steering. In addition, to handle the low cost measurement problem of the reference of front wheel steering angle and the lateral velocity, an [Formula: see text] observer-based control schema is presented to regulate the vehicle stability and handling performance, simultaneously. Finally, the simulation is performed based on the CarSim–Simulink platform, and the results validate the effectiveness of the proposed control schema.


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