Abstract:

Objective Multi-color striped fabrics are one of the important fashion elements in knitwear design. The development of the knitwear fashion trend reveals that fabrics with a small number of colors can no longer meet the needs of consumers. How to carry out a reasonable and feasible secondary innovative design based on multi-color striped fabrics to replace the original monotonous stripes is the challenge to the majority of designers. In this process, it is also a big problem to predict the feasibility of knitting and the color effect of multi-color striped fabrics.
Method To quickly generate a feasible design scheme and three-dimensional (3-D) simulation for multi-color striped fabrics, the pattern design models were constructed and the colored-yarn knitting sequence model was generated according to the knitting principle and characteristics of the striping circular weft knitting machine. The types of colored yarn knitted by each knitting system were calculated and the yarn guiding model was generated. According to the yarn arrangement principle, the yarn threading model was established. The loop geometry and translation mapping models were constructed, and the 3-D simulation method of multi-color striped fabrics was explored with coordinate translation mapping.
Results The design and simulation of eleven-color gradient striped fabric were taken as an example to verify the knitting feasibility for pattern and threading design on the four-color striping circular machine. The fabric design and 3-D simulation process were used to verify the feasibility of the study method (Fig. 2). The pattern model (P) and knitting model (K) were generated according to the pattern design, and the color sequence was reordered from large to small in proportion to produce colored yarn knitting sequence model (Y) (Fig. 3). According to the parameters of the knitting machine and the above pattern model, guiding instructions of yarns were assigned to the guiding devices in each knitting system to obtain guiding model (G) (Fig. 4). Based on the yarn guiding model, the codes of colored yarns in each knitting system were arranged in the yarn threading model(T). Only the number 1 to 4 thread adjusting fingers were arranged in the yarn threading model, enabling patterns of eleven-color striped fabric to be knitted normally on the four-color striping circular machine (Fig. 5). The results of the design model show that the proposed method can effectively predict the knittability of multi-color striped fabrics on the striping machine. For 3-D simulation, the coordinate model of the loop control point (L) was established. The relative position of each loop in the fabric coordinate system was achieved based on the knitting model, hence obtaining the loop translation model (t). Finally, the new spatial coordinate of each loop control point (L') at different positions was calculated. With the help of the Three.js tool, the 3-D simulation of the multi-color gradient striped fabric was achieved (Fig. 6(b)). The results show that the simulation method can visually and clearly display the color effect of multi-color striped fabrics (Fig. 6(a)), and the simulated color effect is regarded as satisfactory.
Conclusion A scientific and effective method for yarn threading design, knittability test and 3-D simulation of multi-color striped fabrics is explored. It is proved by practice that the pattern and threading design model can effectively verify the pattern knittability, so as to guide the fabric design and production. The proposed translation mapping method can effectively reduce the amount of data calculation and improve the running speed of simulation, so as to establish the 3-D simulation of fabric and predict the beauty of color quickly. This method can be applied to the design and 3-D simulation of four-color, six-color, and other multi-color striped fabrics with jacquard. It not only can automatically generate the design scheme according to the pattern, predict the knittability and aesthetics of the machine, but it can also accurately locate the wrong position in the design scheme and generate optimization suggestions, which helps improve the design production efficiency and reduce the waste of raw materials from the root.

Key words: weft knitting, striping machine, multi-color striped fabric, design model, three-dimensional simulation