| Fluid dispensing,which is based on inkjet technology and include arrangement and layer-by-layer deposition of a liquid material in droplet form,has become one of the key processes in electronic packaging and 3D additive manufacturing.In this article,through the study and exploration of existing technology,summarizes of the advantages and disadvantages of existing technology are given.This paper presents a new design of precision fluid dispensing system,which mainly includes the dispensing flow control system driven by voice coil motor(VCM)and the flexible positioning platform driven by voice coil motor.The modeling and analysis of fluid dispensing flow control system and the dispensing position control system are also investigated.Specific work is as follows:(1)Fluid dispensing system driven by linear motor is proposed.Fluid dispensing flow control system,whose piston pump is directly driven by voice coil motor to achieve the precision control dispensing flow and flow velocity,is creatively proposed.Fluid dispensing position control system uses flexible positioning platform driven by voice coil motor to realize a large travel and high precision positioning.Fluid dispensing system architecture is also designed.The host computer control the slave computer under real-time MATLAB control package,and the slave computer respectively transmits data with dispensing flow system through NI6251 and transmits data with flexible positioning system through NI6259.(2)The modeling and analysis of fluid dispensing flow control system driven by VCM is explored.This paper presents a way for system analysis based on splitting and combining.The fluid dispensing flow control system driven by VCM is simplified to three parts including VCM dynamics equations,piston force equations and fluid motion equations.Further,the state space equation of dispensing flow system is obtained through the combination.Moreover,the MATLAB simulation diagram is designed,and some simulation experiments performed.The results show that the system can realize a tracking error of 0.03um of a ramp signal with the slope of 0.5mm/s when it starts and the static differential close to zero.The results demonstrate that the designed fluid dispensing flow control system has a good performance of flow and velocity control.(3)The modeling and analysis of fluid dispensing position control system is explored.The mechanical model of the single flexible spring and the total flexible positioning platform is investigated.An analysis method of flexible micro-positioning stage with large motion is formed in this paper,which provides a theoretical basis for the structure design and parameter optimization of flexible positioning platform.The stiffness and internal deformation stress of rectangular springs and double ? springs are derived based on the Castigliano's second theorem.The proposed flexible positioning platform is simplified to obtain the statics and dynamics equations.Synthesizing the working stroke and working frequency,the VCM model and the dimension parameters of flexible positioning platform are confirmed.Some ANSYS simulation optimizations of platform are also performed.(4)Some experiments of fluid dispensing position control system are performed.The experimental device is set up according to optimize of the flexible positioning platform.In the experiments,the four input three output system is simplified to single input single output system.The pure linear measurement and linear/angle measurement are designed.Respectively,the system identification for each direction and open-loop performance are tested.A PID controller is designed for the closed-loop tracking and resolution test.The experimental results show that the designed fluid dispensing position control system have a translational range of ± 2.33 mm,± 2.28 mm,± 1.2 °along x direction,y direction and around z direction with the resolution of 1 um,1 um,and 0.004°.The linear resonance frequency and the rotation frequency could realize 23.5 Hz and 18.5 Hz. |
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