Makiko Tada

Structure and machine braiding procedure of coupled square braids with various cross sections

Braids provide an ideal preform for textile composite materials while the structure of the braids is restricted by the machine braiding procedure. A wide variety of braided structures found in historical Japanese braids, however, implies a possibility for us to obtain a more rational preform. Thus, a systematic approach to translate the braided structures into a machine braiding procedure is required. We determined the bundle path and number of bundles of square braids and derived formulas giving the optimum number of bundles. The arrangement of horn gears and the number of necessary horn docks were studied. It was found feasible to develop a rotary braiding machine capable of manufacturing braids with arbitrary cross sections.

Comparison of Braiding Skills Between Expert and Non-experts by Eye’s Movement Measurement

A braiding rope is the Japanese traditional rope that a quality and beauty of them have depended on the skill and experience of a braider. In this research, the skill of a expert and two non-experts who practice the braiding everyday and every week, respectively were measured and compared through the eye’s movement measurement and observed the braiding rope quality. The measurement was carried out every month for three times. It was found that the expert show the constant of eye’s focus at the center of marudai plate and reveled a complete pattern of braiding rope. For two non-experts, their eye’s movement wobbled around marudai plate for all trials. However, the braiding speed and quality were developed by the regular training. There are no the defects in the ropes in the trial 2 and 3.

The Technical Effect of Using Kumihimo Disk to Make Braids, Compared to Using Marudai

In the previous study, we learned two important points from the skill of the expert, the angle of the strands on Marudai and the heights of the strands from Marudai. There were four non-experts and two experts. Two non-experts had practice with paying attention to the angle of the strands while braiding; and the other two non-experts had practice with paying attention to the height of the strands while braiding. We then understood a third important point from the skill of the expert, sitting position and posture. In these experiments, we analyzed the effects of non-experts to make braids with both the Kumihimo Disk and Marudai. We tested which braiding technique was more effective for a beginner to use first, and then verified the results. Kumihimo Disk is easier to make braids, and we taught its educational benefits to instruct a beginner on the braiding technique.

Development of Manufacturing Techniques by Hand for Non-straight Braids

Using a Marudai and hand braiding methodology, with repetitive thread movement patterns and bobbin positioning, different curved (curvature radius) braids were created. While the conventional straight braid was made keeping thread arrangements symmetrically on the Marudai, the non-straight braid was realized by breaking the symmetry principle. By using different braiding patterns, braids that are curved can be created by without applying external force. This represents a study of the relationship between the structure and the curve.

Investigation of Evaluation Method for Braiding Strings

The purpose of this study is to evaluate the various properties for braiding strings quantitatively. Flexibleness, compression and reconstruction properties in transverse direction was quantified by using universal testing machine, and relationship between quantitative data, feeling of human being, and braiding structure was investigated. From the result, loading and un-loading curves of the braid fabricated by an expert were smoother than that by a beginner. These results meant the braids fabricated by expert should be uniformly braided. Consequently, by understanding the internal structure of the braids and using mechanical testing for the braids, not only the quality of the braids, feature of the braids for suitable usage can be determined.

Teaching Method of Technique to Make the Braiding

In the previous study, we assigned one expert and two non-experts to braid strands, and measured the movements of their eyes and evaluated the quality of the finished braids. From the measurement result, we clarified two points of the know-how hidden behind the skilled worker’s technique. The first is the height from marudai, a circular frame stand, used for Japanese style braiding and the strand being moved. The other is the angle between marudai, a circular frame stand, and the strands being moved. In this study, we firstly conducted trainings with focusing on the height from the circular frame stand and the angle between the stand and strands. And then, conducted eye movement measurement and motion analysis to verify how the know-how extracted from these results brought the educational benefits to instruct a non-expert on the braiding technique.

Decision-Making Procedure for the Reproduction of Ancient Japanese Braids

Ancient textiles preserved in Japan for more than 1000 years show marked deterioration and their original forms are largely missing. However, unlike other cultural artifacts such as paintings, individual experts are still undertaking reproductions of ancient textiles. The aim of this study is to clarify the decision-making procedure through which an expert can analyze the original ancient braiding structures. The analysis focuses on important parameters including the number of ribs, their interactions with the neighbor ribs (surpass or underpass) and thread direction at the fringes. Through a questionnaire survey, it was found that these parameters allow the expert to deduce the original braided structure. The reproduction works of the expert were also observed using an eye tracking device used to demonstrate how and what the expert mainly focused on during the analysis of the specimen. A positive correlation was found between the results of the questionnaire survey and the real eye movements of the expert.