Development of seamless knitted bra for optimum fit

Abstract

Many existing bras are difficult to fit and painful to wear. Seamless knitted bras have the potential to replace conventional cut and sewn underwired bras particularly for smaller breasted women. However, the designs of commercial seamless bras have limitations in that they tend to compress the breasts and are not totally seamless. The overall aim of this study was to develop new seamless knitted bras for improved fit. The following four specific objectives were set: 1. to design and manufacture a new seamless knitted bra prototype for optimum fit; 2. to develop objective and subjective methods to assess the fit performance of seamless knitted bras; 3. to investigate the relationships between key body dimensions, knitting parameters, finished bra tension and bra fit perception; 4. to identify the optimum tension requirements for different bra components. New design concepts have been devised to overcome the existing limitations of seamless knitted bras by creating a 3D cup shape affording greater volume to accommodate the breasts without compressing them. By innovative design of different structures for different bra sections and graduating the loop length, unique contoured knitted cups have been developed. A further innovation was the method to setthe cup shape using high temperature and steam over a unique 3D former. Furthermore, the bra straps were inventively made totally seamless by using a press-off technique with special knitting structures. To evaluate existing crop top bras and the new bradesigns, a wearer trial and three-dimensional body scanning involving 95 subjects was conducted. A new "Shape Change Ratio" (SCR) for four key breast shape parameters: breast depth height ratio (DHR), breast depth in lateral section, breast curvature in lateral section, and lower to upper height ratio was devised to characterize the changes in breast shape induced when wearing different items of intimate apparel. The relationships between the knitting, body and fit parameters were established. By achieving the optimum fit, optimum tensions for the components are important factors that affect the optimum fit. A newly proposed method called "Binary Search" was developed for determining the individual optimum tensions for the underband and shoulder straps in the minimal number of wearer trials. The application and limitations of the proposed method was discussed. The optimum tensions for the underband were shown to be positively related to the underbust girth and the across bust length; the optimum tensions for the shoulder straps were shown to be positively related to the front neck point to right bust point length and the front to back length.