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This is the second part of our study on needle heating in heavy industrial sewing. In this part, a finite element analysis (FEA) model is presented. Using a commercial FEA software system, ANSYS, the needle is modeled by a number of 3D bar elements and the sewing process is modeled by a series of time and space dependent boundary conditions. The model considers various important factors such as the needle geometry (including the point angle and point length of the needle), the friction between the needle and the fabric, the friction between the needle eye and the thread, the fabrics’ material property, and the sewing conditions. It can predict needle heating in high accuracy. In order to validate the model, a large number of experiments were conducted, in which the needle temperatures were measured using infrared radiometry. It is found that the simulation results match the experiment results very well. Finally, a number of suggestions to reduce the needle heating are presented.

This paper presents an experimental study on needle heating in sewing heavy materials such as upholstery fabrics. In the experiments, infrared (IR) radiometry, high speed line scanning IR radiometry, and high speed IR radiometry are used to obtain thermal images of the needle during sewing. In particular, IR radiometry was used in lower speed sewing (approximately 500rpm). High speed IR and high speed line scanning IR radiometry were used for medium speed sewing (1,000‐2,000rpm). Using Taguchi’s design of experiment method, the effects of various factors are studied including needle conditions (sharp or blunt), sewing speeds, number of stitches per inch, material being sewn, and thread tension. It is found that even with air vortex cooling the needle may still reach high enough temperatures that may affect the sewing quality and even cause thread breakage. This was confirmed via a thread tensile testing experiment. An empirical model of the mean needle temperature is also proposed and tested.

Bar‐tacking is a specialized sewing stitch designed to provide immense tensile strength to the garment which requires a high‐speed precision bar‐tacking sewing machine. This paper aims to present an event‐driven multi‐axis cooperative control method for a bar‐tacking sewing machine.

The control method consists of two parts: the multi‐axis cooperative control and the needle stop positioning control. The challenges include the high speed and the precision. For example, the needle must stop at a set position in milliseconds.

The presented multi‐axis cooperative control can ensure the high speed response and the precision of the cooperative control. The needle stop positioning control is based on a combination of the velocity control and the position control with velocity feed‐forward and limitation.

The bar‐tacking sewing machine requires high‐speed start and stop response and coordination of displacement and velocity only at some given points. Therefore, the conventional multi‐axis cooperative control methods are not suitable. In addition, it requires high‐speed precision control under varying loading conditions.

While there are a number of commercial textile machines available in the market, designing a smart bar‐tacking sewing machine with good speed and precision performance remains a challenge.

The bar‐tacking sewing machine requires highly accurate multi‐axes cooperative control. The presented event‐driven multi‐axis control method is effective. It has not only the required high accuracy but also the fast time response.

Sewing is one of the most commonly used manufacturing processes in the world. Millions of parts are sewn every day ranging from cloths, shoes, furniture, to automobile seat covers. However, it is also one of the least understood processes. In fact, according to literature survey, few know how to calculate the sewing force or the fabric deformation during the sewing. This paper presents our research on using finite element model (FEM) to study the sewing process. The model is developed using ANSYS software system. In the model, the fabric is approximated by a number of perpendicular beam elements with elastic and plastic capabilities. On the other hand, the needle is modeled by a simple elastic beam. The contact between the two parts is modeled by contact elements. The variations of the needle geometry and the fabric material properties as well as the sewing conditions are also included in the model. The model can simulate the needle piercing through a material, and calculates the sewing forces as well as the fabric deformation forming a hole. It has been verified experimentally and can be used to study the effects of the key sewing parameters such as the fabric material properties and the needle geometry.

The purpose of this paper is to present, an optimization problem based on the imperialistic competitive algorithm (ICA) approach for optimizing the needle velocity and variation of needle acceleration in a link drive mechanism of a sewing machine. The optimal geometry of the link drive has been achieved using a non-linear optimization procedure.

As an important study in this case, the authors might refer to a previous work in which they introduced the possibility of replacing the slider-crank mechanism, that is typically used in sewing machines, with a link drive mechanism. The authors regenerate the optimization problem by modifying the objective function and follow a novel optimization method based on the ICA to overcome the drawbacks of that work. In addition, further modification of the objective function with respect to the variation of needle acceleration is applied to assure smooth movement of the needle during sewing process.

The results showed a significant improvement with respect to the optimization of needle velocity and variation of needle acceleration in comparison to that previous work. This clearly justifies the efficiency and reliability of the optimization formulation based on the ICA approach.

Needle temperature is considered as an effective parameter on sewing process efficiency and stitch quality. Needle heat generated during sewing process is directly related to needle velocity in penetration zone which in turn depends on the needle driver mechanism of sewing machine. According to literature survey, few researches have focussed to design a driver mechanism of the sewing machine to reduce the generated needle heat. This mechanism has the ability of reducing the penetration velocity of the needle without affecting sewing speed which consequently can reduce the needle heat generated during needle penetration. The work here is novel regarding implementation of optimization algorithm for this mechanism.