JOURNAL OF JAPAN SOCIETY FOR DESIGN ENGINEERING
Online ISSN : 2188-9023
Print ISSN : 0919-2948
ISSN-L : 0919-2948
Volume 53, Issue 10
Displaying 1-3 of 3 articles from this issue
Paper
  • Yoshihisa MORISHIGE, Koichi SUZUMORI, Takefumi KANDA, Shuichi WAKIMOTO
    2018 Volume 53 Issue 10 Pages 745-760
    Published: 2018
    Released on J-STAGE: October 05, 2018
    Advance online publication: June 27, 2018
    JOURNAL FREE ACCESS

    Interfacial free energy of materials and micro structures on solid surface influence wetting behavior at solid-liquid interface. Controls of wettability by making constant-shaped micro surface structures have been approached. By reference to those approaches, the authors consider that deformation of micro surface structures changes wettability. In this report, we prepared a micropillar array on a silicone rubber sheet. The diameter and the height of pillars were 10 μm or 200 μm. A water droplet of volume 5 μL was dropped on the micropillar array. Pitches of pillars increased as the rubber sheet was extended, and contact angle of the droplet decreased. Pitches decreased as the sheet was contracted, and the contact angle increased. The contact line of water droplet jumped from exterior pillars to interior pillars when pitches increased. This contact angle change will contribute to surface-improvement of soft actuators.

    Download PDF (2366K)
  • Kazutake UEHARA, Fumio OBATA
    2018 Volume 53 Issue 10 Pages 761-774
    Published: 2018
    Released on J-STAGE: October 05, 2018
    Advance online publication: June 11, 2018
    JOURNAL FREE ACCESS

    In machine tools, increases in rotational speed and feed rate result in increased frictional heat, leading to thermal deformation and decreased machining accuracy. When analyzing thermal deformation, it is critical to accurately estimate the heat quantities at heat sources. To reduce machining errors induced by the thermal deformation of machine tools, we recently proposed a method to estimate the steady-state heat flux acting upon a machine tool body. In this method, quasi-steady-state increases in machine tool body temperature are used to estimate the heat flux at the heat source with sufficient accuracy for practical use. In this paper, an objective function Δ j, for which the ideal value is 0 K2, was obtained from the residual sum of squares between measured quasi-steady-state temperatures rises and those obtained by finite element analysis at all evaluation points, and the effects of the layout and number of temperature sensors on the accuracy of estimated heat quantities at steady-state heat sources were evaluated. The results suggest that the layout and number of temperature sensors should be selected to include temperature evaluation points where factorial effects are large, which are obtained using S/N ratios defined as smaller-is-better response in quality engineering. Where Δj became smaller than 100 K2, the heat quantity at the steady-state heat source could be estimated from the intercept of the approximate linear regression equation given by least squares method between the optimal solution and Δ j. Locating the temperature evaluation points both close to and far from the heat source is useful to decrease the number of points. Setting the initial steady-state heat flux at the heat source in consideration of the approximate steady-state heat quantity is an effective method to decrease the search time for optimal estimated heat quantity.

    Download PDF (2485K)
Note
  • (Conception, Design, and Creation of a Coupling)
    Koichiro YAMADA, Kaoru TOYODA, Takao MUROMAKI, Atsushi SUDA
    2018 Volume 53 Issue 10 Pages 775-786
    Published: 2018
    Released on J-STAGE: October 05, 2018
    Advance online publication: July 26, 2018
    JOURNAL FREE ACCESS

    We report an example of mechanical design and drawing education at National Institute of Technology, Maizuru College, and survey a practical method of education for mechanical design based on a questionnaire conducted on students. In this report, we focus on practical training in engineering, which is managed in the educational method called "active learning". The students study a manufacturing process through planning, designing, and producing a new coupling based on their own ideas. The new coupling has 20 mm input and output shafts and is 98 mm in length, width, and height. First, we introduce the content and schedule of this subject. Next, we describe a questionnaire on class activities. Finally, we show two drawings; they are from the teams that finished the production early and late. The results of the questionnaire showed as follows: 1) The students understand the importance of teamwork and communication skills. 2) They spend too much time on the production to keep to the schedule. 3) The preliminary survey is carried out smoothly. 4) The delay results from lack of working hours and machine tools. The results show that time management is important. This activity will enhance our faculty development.

    Download PDF (2953K)
feedback
Top