Volume 15, Issue 2, 2020/Journal Proceedings in Manufacturing Systems

Abstract: This paper is a presentation of Greeny’s evolution over the design phases. The study started with an analysis of the existing products on the market, the requirements for such vehicles and the applied legislation in this case. There were mainly 3 versions of Greeny: V1.0, V2.0, V3.0. Each version brings optimisation in terms of autonomy, stability and ergonomics. The goal is to obtain a cost-effective product using mostly prefabricated parts having a high degree of recyclability. The evolution of different subassemblies (Handlebar, Fork, Folding System, Tilting System, The Hull, Rear Axle) is presented in this paper. Materials used for Greeny are also presented since we tried to lower the weight of the vehicle which influences its autonomy. For better damping, we have chosen for V2.0 and V3.0 a different type of fork which lead us to a change on the folding system that also is easier to be handled. The handlebar was changed to improve ergonomics and the safety of the passenger. It is also easier to be set to height. The safety of the passenger was considered also when the tilting system was changed. This change also brings a better posture on the vehicle. The hull design was decided by the position of the batteries that was changed to improve stability and ergonomics. A better feet position was obtained changing the design of the rear axle.

Key words: electric tricycle, safety, stability, design..

pp. 53-58 View full text

Optimization of the industrial process of painting plastic bars using kaizen methodology

Aleodor-Constantin BOGDAN^1,*, Elena-Iuliana GINGU (BOTEANU)², Florea Dorel ANANIA³, Vasile BENDIC⁴

¹⁾PhD Student, Robots and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

²⁾PhD, University ”Politehnica” of Bucharest, Romania and Advanced Technologies Institute

³⁾PhD, Assoc. Prof., Robots and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

⁴⁾PhD, Prof., Robots and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

Abstract: In recent years, Kaizen methodology has been widely used to improve the activities in the manufacturing systems. The improvements achieved by applying Kaizen are small, but at some point, evaluated over long periods are beneficial to organizations. In this regard this article provides optimization strategies by using Kaizen methodology in order to improve the painting process of the plastic parts (bars) and to ensure a growing in cadence from 67 vehicles/hour to 75 vehicles/hour. A real case study from a vehicle company is analyzed, new ideas to improve the quality of the painting product are provided and the financial impact of the improvement proposals is presented.

Key words: painting process, Kaizen, optimization, financial impact.

pp. 59-64 View full text

Investigation and modeling of cutting tool temperature in turning of Inconel 625 steel by using Taguchi method and long short term memory network

Shpetim SALIHU¹, Miha KOVACIC², Uros ZUPERL^3,*

¹⁾ Phd student, University of Maribor, Faculty of mechanical engineering, Maribor, Slovenia

²⁾ Assoc. Prof., Štore Steel, Slovenia

³⁾ Assoc. Prof., University of Maribor, Faculty of mechanical engineering, Maribor, Slovenia

Abstract: In this paper, the results of an experimental investigation of cutting tool temperature in turning operations are presented. The cutting tool temperature is a very relevant in order to avoid excessive tool wear and tool damage. This study explains the impact of cutting speed, feed rate and depth of cut on cutting tool temperature during machining of Inconel 625 steel. Taguchi methodology is used to formulate the experimental layout. A Taguchi L27 design of experiment is applied to analyze the effect of each cutting parameter on the cutting tool temperature. Minitab software is used to process the experimental data and to develop a mathematical regression formula among three main cutting parameters and tool temperature. The obtained data in experimental work are used to perform deep learning using the Long Short-Term Memory (LSTM) network in order to predict the cutting tool temperature. The obtained results indicate that feed rate has the largest effect on cutting tool temperature followed by depth of cut and cutting speed. The predicted cutting tool temperature values obtained from LSTM network are very close to those of experimental, where the average percentage error from test base is 1.93%. According to the results, the LSTM predicts well the expected outcomes, and the standard deviation is in acceptable interval for predicting the cutting tool temperatures.

Key words: machining, turning, cutting tool temperature, prediction, Taguchi, deep learning, LSTM.

pp. 65-70 View full text

Reengineering a solution for small companies in the context of the pandemic

Elena SIMA^1*

¹⁾ Lecturer, PhD, Faculty of Engineering, "Lucian Blaga" University of Sibiu, Romania

Abstract: Reengineering consists of reinventing business by using the latest technology and, therefore, making leaps in performance. Reengineering and restructuring are not synonymous. Restructuring responds to the interests of shareholders to increase efficiency and effectiveness, while reengineering is concerned with the situation of employees and customers. Reengineering aims to change the way processes are conducted and, as a rule, does not change the organizational chart and does not involve the disappearance of positions and dismissals of employees. The paper presents how, in the difficult pandemic period in which many businesses were reduced or even disappeared, a small company, using the principles of reengineering, reinvented itself and manages to survive. The specialized literature mentions that among the companies that resort to reengineering are those that face great difficulties. It is known that trouble teaches you what to do but the company in question had no great problems before the pandemic. They could send employees into technical unemployment, but they wanted to continue production by making the products that were requested online and start the production of protective masks from the debris that fell from the cutting process, given that the raw material met the requirements. In the first period, they were donated to hospitals and later they sent for sale. The employees were divided and worked in shifts to respect the distance, thus avoiding possible illnesses. Sales increased in time, people did not lose their jobs, nor did their income decrease, customers were satisfied, and the business also grew.

Key words: reengineering, process, efficiency, employees, customers.

pp. 71-80 View full text

The corporate management model from the perspective of organizational culture

Corina BOTEZ (CONSTANTIN)^1,*, Gabriela Beatrice COTEȚ (NICA)²

¹⁾ PhD Eng., Master Student, Robots and Manufacturing Systems, University "Politehnica" Bucharest, Bucharest, Romania

²⁾ PhD Lecturer, Training Department for Teaching Career and Socio-Human Sciences, University "Politehnica" Bucharest, Bucharest, Romania

Abstract: Organizational culture is a topical issue today, holding an important place in the process of transformations societies go through, implicitly organizations. At the same time, the success or failure of an organization’s activity is partially determined by the organizational culture it adopted, this being an essential element associated with progress in society. The notion “organizational culture” has its origins in the field of sociology and anthropology being a concept used to clarify the so-called “social order”. The purpose of this paper is to research and compare different types of organizational cultures adopted by companies of a similar size in Romania and Serbia. In order to carry out the practical study, two tools for evaluating the organizational culture were applied to the members of the organizations, namely, the questionnaires created by the specialists in the field: Roger Harrison, Kim Cameron, and Robert Quinn. After applying the questionnaires and interpreting the data obtained, it was found that all the companies analysed adopted a mixture of different types of organizational culture described by the three authors. The study can also provide relevant information for the managers of the studied companies regarding a better understanding of the role of organizational culture in the company's activity and its influence on its members. The study can also help managers by contributing to improving the performance and productivity of organizations, in order to diversify the business under good conditions, without hindering the performance improvement.

Key words: culture, organizational culture, cultural dimensions, medium-sized organizations, evaluation.

pp. 81-90 View full text

Study regarding flight autonomy estimation for hexacopter drones in various equipment configurations

Mihai-Alin STAMATE^1*, Adrian-Florin NICOLESCU², Cristina PUPĂZĂ²

¹⁾ Ph.D. Student, Eng., Robots and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

²⁾ Prof., Ph.D., Robots and Manufacturing Systems Department, University "Politehnica" of Bucharest, Romania

Abstract: The use of multirotor drones in a wide range of applications in the civilian environment has seen an uprising trend over the past decade. It is estimated that by 2025, the market for drones used in the civilian environment will reach about 48 billion USD. Although there are currently different propulsion variants for the multirotor drones, such as LiPo batteries, fuel supply systems, and hybrid solutions none of reported articles comprise a synthetic comparative study from the designer point of view. This paper aims to address a hexacopter drone from the perspective of flight autonomy, which uses as a propulsion system 6 BLDC (Brushless Direct Current) motors, powered by LiPo batteries. This research was done by carrying out comparative studies, with different equipment configurations, by taking into account all of the hexacopter components: the frame, the propulsion system consisting of propellers, motors, ESCs – Electronic Speed Controller, LiPo batteries, communication/ telemetry/ FPV – First Person View systems, and different types of payloads respectively. The study was performed using online platforms: https://www.ecalc.ch/xcoptercalc.php, https://flyeval.com/, http://www.drivecalc.de/, and represents an alternative to choose the optimal combination of components, to ensure the best flight range. The novelty of the paper consists in the customization of available platform information gathering it in an extensive comparative study to allow the best decision in multirotor drone design. Because the work has also limitations, the continuation of the research is expected.

Keywords: drone, hexacopter, brushless motor, payload, autonomy.

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