The puncture force during sewing is a critical factor affecting sewing quality. In this study, the puncture process is divided into five stages, a mechanical model of the puncture process is established, and a quantitative expression is achieved. Using the ANSYS Explicit Dynamics method, a finite element analysis model of the penetration process was developed to investigate the influence of fabric structure (thickness and warp and weft density) and needle geometric parameters (point height, taper angle, and shank diameter) on penetration force. The results indicate the following: Two distinct force peaks occur during needle penetration—one at the instant of fabric piercing and another when the needle shaft enters the fabric. Increasing fabric thickness causes the former peak to rise significantly, while the latter peak increases more gradually. Puncture force decreases significantly with reduced warp and weft density. When density decreased from 85 × 85 TPI to 80 × 80 TPI, the first peak decreased by 18.5% and the second peak by 67.4%. A further decrease in warp and weft density to 75 × 75 TPI resulted in peak reductions of 58.48% and 20.64%, respectively. Additionally, the needle tip cone angle and tip height are critical parameters affecting the peak penetration force. The comparative analysis of improved standard needle tip cone angles and tip heights demonstrates that the modified machine needles exhibit lower peak penetration forces, confirming the effectiveness of the needle improvement methods proposed in this study. The research methodology and results presented herein provide an effective numerical simulation-based approach for needle selection and penetration force evaluation in fabric piercing and sewing.
Mei et al. (Thu,) studied this question.