Research And Realization Of Auto-Sewing Software For Full-Automatic Lockstitch Machine Based On DXF File

Sewing machinery industry is one of the important industries in China light industry. The sewing machine, which is represented by the lock-stitch sewing machine, plays an important role in supporting garment processing and other related industry development, enhancing the living standard, promoting social progress, and promoting national economic development. In the fierce market competition today, only the lock-stitch sewing machine manufacturers make advanced full-automatic lockstitch machine and constantly improve the sewing efficiency and quality can they meet more stringent requirements of the downstream garment industry.Therefore, the researchers from Huazhong agricultural university designed a new type of numerical controlled lock-stitch sewing machine. The lock-stitch sewing machine has the following characteristics:(1) using CAD/CAM technology and taking DXF file as the data source file; (2) adopting the unique mechanical structure—the head separating from the spindle bed; (3) the CNC system bases on the IPC and Turbo PMAC2. So, a set of reliable NC software plays a vital role to the fully-automatic NC lock-stitch sewing machine system. Among them the auto-sewing software is an essential core component of NC software for automatic NC lock-stitch sewing machine, and the command center of automatic sewing work.This paper studies and realizes the auto-sewing software for IPC, including the system initialization, the data optimization, the simulation of sewing process, the generation of NC-code and the status real-time monitoring modules.(1) The system initializationThe system initialization module is the prerequisite of the normal work of the whole lock-stitch sewing machine system, including the communication with Turbo PMAC2, the system reset, the detection of template edges and the scanning of template.(2) The data optimizationThis is the core of the software. The full-automatic NC lock-stitch sewing machine adopts CAD/CAM technology, that is to say it uses the template DXF file as data source files for subsequent sewing work. It is necessary to optimize the data in the template DXF file before sewing work. In order to realize the data optimization, this paper specially made the format protocol for template DXF file, based on the format of DXF file and the sewing process, which is used to regulate the generation and read of template DXF file. And in order to abstract and store the data in the template DXF file, this paper designed specific data structure and algorithm. On this basis, combining with the sewing process requirements, this paper optimized the data in the template DXF file, including optimization of stitches, process parameters and sewing path, aiming at shortening the spare travel time and improving work efficiency.(3) The simulation of sewing processIn order to intuitively validate the results of data optimization whether meet the sewing process requirements, this paper simulated the whole sewing process. And only when the results of the sewing process simulation achieves the desired process requirement can the template DXF file be directly converted into NC code for sequential sewing automated production. In order to achieve a better simulation effect, this paper made the agreements for simulation. And in order to realize the realistic simulation process, not only should the stitches that meet process requirements be drawn in the template display window, but also the effects, such as repeat, plotting, backstitch, pausing and marking, should be expressed in accordance with the agreements for simulation. Among them, the repeat and backstitch was focused by this paper.(4) The generation of NC-codeThe optimized template DXF file can be converted to executable NC code for PMAC after the results of sewing process simulation being approved. The flow of the NC code generation is similar to the one of the sewing process simulation, that is to say, not only should the stitches that meet process requirements be converted to NC code, but also the auxiliary NC code for the detection of template edges, the scanning of template, pausing, trimming, marking and tension control should be generated. This paper presents the flow of NC code generation.(5) The status real-time monitoringIn order to realize remote network control, harmonize and integrate above modules and provide module interfaces, it is needed to monitor and measure the sewing states and the tension of top-stitches.Among the modules, the system initialization is the prerequisite; and the status real-time monitoring is the brain and provides control logics and interfaces; and the data optimization, the simulation of sewing process and the generation of NC-code are the body and realize specific functions. The actual running results at the lock-stitch sewing machine prototype for both the single module and the software show that the auto-sewing software studied by this paper has realized automatic sewing function on the whole.