Abstract: Computer embroidery machines are the main member of the decorative sewing machine industry. They are widely used in the sewing of all kinds of decorative patterns, such as the production of clothing signs and decorative patterns, enjoying a very important position in the textile and garment industry.
The multi-head embroidery machine frame features a large-span crossbeam structure, and its machine head incorporates an eccentric cam mechanism. Operating at high speeds, this setup frequently produces significant vibrations, thereby impacting the quality and production output of embroidered products. In response to the vibration challenges associated with the crossbeam in the multi-head embroidery machine, the concept of statically indeterminate crossbeam frame of multi-head computer embroidery machine was put forward through multi-body dynamic analysis and finite element analysis. By installing semi-cylindrical balance blocks on both sides of the machine head, the inertia force of the machine head's movement was reduced, and internal excitations were minimized. The design concept of a statically indeterminate beam was employed to strengthen the constraints on the crossbeam, reduce its amplitude and improve the vibration cycle. The vibration conditions of the crossbeam were analyzed and solved through a combination of ADAMS dynamic analysis and ANSYS transient dynamic analysis. For the force situation of the large-span embroidery machine crossbeam, theoretical calculation methods for maximum displacement and nodal vibration amplitude were employed and the consistency between finite element methods and theoretical calculation methods was verified. By utilizing ADAMS software, optimal design dimensions and installation angles for the balance block were obtained, significantly reducing the impact of the machine head movement on the crossbeam. The design concept of employing a statically indeterminate beam and the theoretical analysis results proposed in the design are applicable to various optimization scenarios with similar multiple loads and large spans. This approach is intended to mitigate vibration issues in crossbeams.
The result showed that compared with various frame vibration reduction schemes in the market, the statically indeterminate beam proposed in this paper can obviously optimize the vibration amplitude and vibration period, which help the cross beam to get rid of the periodic impact caused by the head operation, thus greatly reducing the vibration problem of the long-span cross beam of the multi-head embroidery machine under the high-speed operation. This study has certain significance for improving the process accuracy of embroidery machine under high speed operation. 

Key words: embroidery machine, long span beam, statically indeterminate beams, finite element, suppression, cyclic load

摘要： 多头刺绣机机架为大跨距横梁结构，机头为偏心凸轮机构，在高速工况下常激发出强烈振动，导致刺绣产品的质量和产量均受到影响。为了解决多头刺绣机横梁的振动问题，通过多体动力学分析和有限元分析，提出了多头电脑刺绣机超静定横梁机架的概念。通过机头两侧配置半圆柱形平衡块，降低机头运行的惯性力，减小内部激励；采用超静定梁的设计理念，对横梁的约束进行加强，降低横梁的振幅，改善振动周期。经与目前市场上多个机架减振方案对比，文章提出的超静定梁的振动幅值具有明显优势，横梁振动周期发生明显变化，摆脱了机头运行带来的周期性冲击影响，从而大幅度减少刺绣机由于机头高速运转而导致的大跨距横梁振动问题，有利于提高刺绣机高速运转下的工艺精度。

关键词: 刺绣机, 大跨距横梁, 超静定梁, 有限元, 抑振, 周期性负载