Structure Design And Drop Simulation On Miniature Commercial POS Machine

In recent years,under the impact of various objective factors,social and economic development has encountered great challenges,China’s social and economic activities gradually transit from offline to online as a majority.Before the outbreak of the COVID-19 epidemic,in order to improve the level of retail stores and consumers’ shopping experience,merchants would often buy POS machines with high-end and attractive appearance and large screen size to attract customers.Such kind of POS machines are not only expensive in price,but also space-eating with the accessories such as electronic scales,printers,scanning boxes and so on.Therefore,they don’t fill into the special economic situation at the moment: the small and medium-sized retail enterprises and online businesses require POS machine to be small in size and reasonable in price.In addition,the traditional product structure design relies more on the design experience of structural engineers and the drop impact test,which not only wastes a lot of materials,increases the production process,but also extends the product development cycle.With the development of finite element technology,more and more engineers began to pay attention to simulation analysis,through which not only the structural performance is improved,but also the development time is shortened.The main contents are as follows:（1）POS machines are classified according to cashier equipment in different consumption scenarios,and the working principles of POS machines are analyzed by taking milk tea shop as an example.Secondly,from the perspective of appearance,structure,display screen and other aspects of the existing competitive products in the market,combined with product modeling materials,structure,color,environment and other relevant factors,a conclusion is drawn.For small and medium-sized retail enterprises and online businesses,the POS machines on the current market cannot meet the current special economic situation under the threat of the COVID-19 pandemic,and it is clearly that a new type of POS machine needs to be designed.（2）By analyzing the internal structural components of POS machine,the shell design requirements from the perspectives of shell material,structural stiffness,strength,installation and disassembly are put forward and some structural design points such as the shell wall thickness,buckle connection mode,reinforcement characteristics,and rounded corner characteristics are analyzed in detail.With the help of Solid Works3 D modeling software for product module development,a 3D solid model is established to finish the design of this product.（3）The basic theory and solving steps of finite element method are studied,and the model is preprocessed according to the finite element analysis process.The complex parts in the model were simplified according to the simplification principle,and the simplified model was imported into Workbench simulation analysis software to determine the structural performance parameters of each part in the model.Tetrahedral mesh and hexahedral mesh are used to divide the whole machine model according to the grid partitioning theory.Finally,the connection mode of each component in the model is analyzed,and the contact surface,target surface and corresponding contact type are set up to complete the preprocessing of the finite element model of the whole machine.（4）By fully analyzing the theory of drop impact,the model is simulated from a height of 762 mm with three typical drop gestures: face drop,angle drop and edge drop,and the stress,strain and deformation cloud pictures of each output time node under different fall conditions were obtained.The main parts of the model are Analyzed to find the vulnerable parts of the structure,and to put forward the corresponding optimization scheme.The results show that the overall antidrop performance is improved effectively,which provides a reference for the structure and optimization design of the same type of products.