Sun-Pui Ng

Application of the Box-Behnken design to the optimization of process parameters in foam cup molding

Currently, foam molding technologies are widely adopted for most bra styles, which demonstrate the incomparable advantages in the contemporary intimate apparel industry. The determination of proper molding conditions, such as molding temperatures and length of time on the basis of cup sizes and styles, is crucial in achieving the required cup shape with high stability, which is regarded as the most challenging part of the molded bra making process. To determine the optimal process parameter settings, numerous process trials are generally required to evaluate the molding variables and their interactions. This study proposes a novel systematic methodology to identify the optimal molding process parameters based on design of experiment (DOE) and a parameterization-based remesh method to evaluate the 3D shape conformity of molded cups. By solving the regression equation obtained from a Box-Behnken design (BBD) and analyzing the response surface plots, the results prove that molding temperature has greater influence than the length of the dwell time on the 3D shape conformity of molded cups. The optimal molding conditions can be determined for the cup depths of different sized mold heads, which are validated by the experimental results.

Studies of Three-Dimensional Trajectories of Breast Movement for Better bra Design

This paper presents a new method for evaluating 3D breast motion relative to the thorax using a new breast coordinate system. A local virtual origin is defined by four breast boundary points, in a constant relative distance from four bone-fixed thoracic points. The validity and reliability of the method was tested with 11 subjects and confirmed (interclass correlation coefficient = 1.00). The feasibility of the new system was tested with two subjects with pert and ptotic breasts, respectively. Each subject participated in motion experiments whilst treadmill jogging, with and without a sports bra. In the braless motion experiments, the breast movement trajectories of six breast positions resembled a butterfly shape. In a jogging cycle, there was a single anterior and medial peak, and a double peak in the vertical breast displacement. The ptotic breast displacement during jogging was larger and wavy, with a more evident vertical and medial-lateral vibration. It tended to move more medially and anteriorly than the pert breast. The bra trajectories of the subjects wearing sports bras showed that the superior movements of the upper breast need further control. To achieve this, it was proposed that the neckline of the bra should better fit the upper breast boundary.

Innovation and technology of women's intimate apparel

Assessment of womeni?½s body beauty Breast measurement and sizing Innovations in bras Bra pattern technology Innovations in girdles Physical and physiological health effects of intimate apparel Pressure evaluation of body shapers Intimate apparel with special functions Performance evaluation of knitted underwear Process innovation in seamless intimate apparel.

Identifying effective design features of commercial sports bras

This paper identifies the effective design features of commercial sports bras by evaluating the reduction of breast displacement during activities. Four subjects, with breast and body types representative of Chinese females of age 24–40 years were studied while they performed activities either braless or wearing one of seven different sports bras representative of the range commercially available. The three-dimensional movement of the breasts was derived by videoing the motion of breast markers attached at six different breast positions using a Vicon 3D motion analysis system. The breast displacement relative to the thorax was measured using a validated local “thorax–breast 3D coordinate system”. The results showed that there was a significant difference in breast displacement between the different breast markers. The bra samples generally achieved the greatest reduction in breast displacement in the medial–lateral direction. The reduction in breast displacement was positively related to the gore height, shoulder strap width, neckline height and side seam depth. The underlying mechanism of breast movement and bra support is also discussed. The study concluded that the most effective bras had the following features: compression type, short vest style, high neckline, slings, cross back, bound neckline, no centre gore, no wire, no cradle, no pad and a non-adjustable wide strap. This provides practical guidelines for bra designers and manufacturers to develop more supportive bras for women performing these physical activities.

Methods of studying breast motion in sports bras: a review

There is exponentially increasing number of research publications studying breast motion in sports bras. However, there are large varieties of their methods and findings. To critically evaluate the consistency and limitations of previous breast motion studies, a systematic review of all articles on breast motion in sports bras was performed. A total of 17 fully extracted studies included 216 subjects, aged from 20 to 60 with bra cup sizes from A to J. They participated in only four types of activities with or without bras, but not in randomized controlled trials. Most studies focused on the vertical nipple movements, but seldom examined the three-dimensional breast velocity, acceleration, and trajectory. The sample sizes and the types of activities were limited. The reference frames were not stable in most studies. To study the realistic breast movements in the future, a standardized local coordinate system will be needed.

Brilliant Whiteness Surfaces from Electrospun Nanofiber Webs

Inspired by the brilliant whiteness of Cyphochilus beetles found in Southeast Asia, we produced an electrospun nanofiber web with a very high CIE whiteness index, thus providing an extremely effective and efficient light shielding layer for textile and industrial applications. Polyurethane, polymethyl methacrylate and poly(ethylene terephthalate) electrospun nanofiber webs were prepared on a polyurethane foam surface of about 30 × 30 cm 2. Processing parameters, such as the type of solvent used, polymer concentration and collection geometry were carefully selected and studied in order to produce an interconnecting network of fibers around 250 nm in diameter. The whiteness index of the electrospun samples was measured by a spectrophotometer. The polyurethane nanofiber web showed a very high CIE whiteness index exceeding 85. Excellent anti-yellowing effects of electrospun nanofiber webs on polyurethane foam were also illustrated via phenolic yellowing and UV light resistance tests.

Inducing hydrophobic surface on polyurethane synthetic leather by atmospheric pressure plasma

This study investigates the use of atmospheric pressure plasma (APP) treatment for improving surface hydrophobicity of polyurethane (PU) synthetic leather with hydrophobic organosilane precursor. The precursor was deposited on the synthetic leather surface by means of APP treatment regarded as an effective, simple, and single-step low pollution method. The result showed that under a particular combination of the experimental parameters, a hydrophobic surface was achieved on the APP treated sample with contact angle of 94 °. Moreover, the hydrophobic surface is stable for at least 30 days after APP treatment.

Parametric design and process parameter optimization for bra cup molding via response surface methodology

Seamless and traceless undergarments have rendered foam sheet molding as an important manufacturing technique for the intimate apparel industry. Seamless bra cups are made by one-step forming technology. The three-dimensional (3D) cup shape is formed by using high temperatures and pressures with flexible polyurethane foams. Nevertheless, the mold head design process and control of the bra cup molding process are highly complicated and error prone. There is limited knowledge about the effects of foam properties, molding parameters and foam cup geometric parameters on molding process optimization. This research presents a response surface methodology as the approach for parametric design and process parameter optimization of bra cup molding. The proposed approach integrates 3D scanning via reverse engineering, parameterized-based remeshing and registration algorithm, non-linear mathematical prediction models for cup shape conformity, a model of foam shrinkage and example-based bra cup design and grading to optimize the bra cup development and production process. The experimental results show that this method is highly effective and more timesaving in the design and development of new products, as well as providing consistent quality control of the bra cup molding process.

Parametric study of CF4-plasma on the hydrophobicity of polyester synthetic leather

Atmospheric pressure plasma (APP) technology has been proven to be an effective method for improving the hydrophobicity of fabric surface. While many researchers have worked on apparel fabrics, polyester and synthetic leather fabrics, popular in the luxury textile market, have been examined rarely. In this regard, this paper reports the effects of APP treatment using tetrafluoromethane (CF4) as the polymerizing monomer on hydrophobicity of polyester synthetic leather. The polyester synthetic leather samples were treated under various parameters and hydrophobicity was found to be greatly enhanced under a certain range of treatment conditions. An optimization of the treatment parameters was conducted and the results showed that a hydrophobic surface with a contact angle of 106 ° was achieved, compared to the untreated sample’s 0 °.

Prediction of fabric tension and pressure decay for the development of pressure therapy gloves

Pressure garments are commonly used in the treatment of hypertrophic and deformed scars. Pressure monitoring is crucial for effective pressure therapy. A new method is proposed to predict the amount of pressure acting on skin induced by pressure therapy gloves on the basis of hand curvatures extracted from three-dimensional hand images. The non-linear tensile properties of seven types of fabrics with various structures and their tension decay in relation to prolonged usage and reduction factors are examined. By taking into consideration the fabric elongation when the gloves are worn, a total of 36 pressure gloves are tailor-made by using three reduction factors. Based on the fabric tensile behavior, the corresponding glove pressure is predicted by the local strain, fabric tension per unit length and curvature of hand surface. No statistical difference at significance level of 0.05 is found between the predicted glove pressures and the measured values. In the measuring points on the dorsum of the hand, except the metacarpal site, the root mean square error ranges from 0.79 to 1.18 kPa. The investigation confirms that all pressure gloves lose tension and, therefore, pressure delivering ability upon repeated uses. It is also revealed that the pressure measuring positions and their corresponding curvature and geometry changes caused by hand movements and postures are closely associated with interfacial pressure delivered by the glove.