Abstract:

Objective Yarn packages on a creel typically employ negative warp feeding, allowing for flexible yarn supply adjustments according to the demands of jacquard patterns during the warp knitting process, which enables the manufacture of fabrics with complex pattern designs. However, due to the complexity of jacquard organization and the variability of pattern design in warp knitting the jacquard fabrics, there is currently a lack of effective methods to calculate the yarn consumption of jacquard warp yarns supplied from the warp knitting creel. This deficiency results in a waste of manpower and material resources in jacquard yarn procurement. Therefore, predicting the consumption of warp yarns in warp knitting jacquard fabrics can effectively help textile enterprises reduce costs and increase efficiency.

Method The aim of this study is to construct a jacquard yarn consumption prediction model for warp knitting jacquard fabrics. Through an in-depth analysis of the warp knitted jacquard fabrics, a mathematical model is established to describe the characteristics of their structural units. Based on the analysis of the knitting patterns of these structural units, a fabric geometric model is proposed to calculate the yarn length of the structural units by incorporating actual production process parameters. The prediction model for jacquard yarn consumption is constructed to calculate the yarn consumption for warp knitting jacquard fabrics and is put on trial for practical production.

Results In this paper, by analyzing the structural characteristics and jacquard decomposition path of warp knitted jacquard fabrics, a classification method for identifying structural unit is proposed based on the jacquard yarn movement matrix. The jacquard pattern is categorized into five types of structural units to achieve the quantitative characterization and classification statistics. The geometrical model of the structural unit in a three-dimensional Cartesian coordinate system is constructed by combining the actual morphology of the structural unit. The calculation formula for the length of the loop trunk and the extension line is derived, taking into account of the process parameters such as the machine gauge, the diameter of the yarn, and the distance of the detangling plate. Combining the statistical model of the structural unit with the length model of the structural unit, a prediction model for the yarn consumption in warp knitted jacquard fabric is proposed, realizing the calculation of the total yarn consumption of jacquard yarns within the pattern unit. To verify the reliability of the model, a warp knitted jacquard fabric was knitted on a double needle-bed jacquard warp knitting machine from Fujian UNIC Machinery Co., Ltd. The jacquard raw material consumption for making the fabric sample was predicted using the proposed model, and the error between the predicted value and the measured value was less than 5%, which is within a reasonable range.

Conclusion This paper categorizes jacquard patterns into six types of structural units and derives the calculation formula for the length of the loop trunk and the extension line, taking into account of the process parameters such as the machine gauge, the diameter of the yarn, and the distance of the detangling plate. By combining the statistical model of the structural unit with the length model of the structural unit, a prediction model for the yarn consumption for making warp knitted jacquard fabrics is proposed, enabling the calculation of the total yarn consumption of jacquard yarns within the pattern cycle. The prediction error of the model on actual fabric is 4.3%, indicating that it can meet the accuracy demands of enterprise production. The application of this model can be used to provide textile enterprises with dynamic raw material demand predictions, optimize procurement plans, reduce inventory redundancy, and offer a theoretical basis for the intelligent tuning of process parameters.

Key words: warp knitting, creel jacquard, geometric model, material consumption, prediction model, cost control of warp knitting production