Control And Equipment Development Of Precision Dispensing For Micro Device

Micro device,like inertial device,is widely used in aerospace transportations like space shuttles,missiles,spacecraft,etc.Precision dispensing technology is involved in most development processes of micro device and the dispensing quality will directly affect its overall performance.At present,most of the dispensing work is done by workers under the microscope due to special dispensing requirements,such as the small size of the inertial device,high viscosity of the adhesive,high precision positioning demand.So,there is an urgent need to develop a precision dispensing system that request low positioning requirements for small devices,have accurate trajectory and dispensing amount for high viscosity adhesives.Further research on the key technology of dispensing monopolized by foreign countries,not only will improve the efficiency and quality of dispensing products,but also can promote the development of domestic dispensing technology to a certain extent.Aimed at completing the sealing task of a miniature inertial device,this paper developed an automatic precision dispensing system based on machine vision.The equipment is divided into precision positioning module,visual inspection module,micro-injection module and human-computer interaction module.The precision movement module is to complete the micron level positioning according to the preset dispensing trajectory.The visual inspection module is to fulfill the identification of parts and the control of dispensing trajectory.Micro-injection module is to realize the manipulation of dispensing action and achieve an accurate adhesive amount.The human-computer interaction module,as a communication window between the user and the equipment,is to improve the efficiency of dispensing operations by optimizing the operating steps.Combined with the time-pressure dispensing characteristics and sealing task analysis of the inertial device,this paper made in-depth research on some key control techniques in dispensing technology,including the control of dispensing consistency and vision identification of inertial devices.Firstly,a precision dispenser was selected and controlled by analyzing the influencing factors that affect dispensing amount.Then the viscosity characteristics and curing characteristics of the adhesive used in the experiment were tested.In order to solve the contradiction between the increase of camera resolution and the narrowing of vision field,a motion control program of “dispense where mouse to click” was designed.At the same time,to improve the flexibility of this dispensing system,an error compensation measure based on the droplet image was used to make up the needle mounting deviation.The calibration scheme of needle reference position was put forward,leading gap between needle and substrate controlled in 10?m by using the precision laser sensor.Based on machine vision technology,a compensation scheme of "image center first,then deviation adjust" is proposed to compensate installation eccentricity between parts and turntable.Installation and debugging of hardware was accomplished.With the mixed programming of LabVIEW and Matlab,control software of precise dispensing system was prepared.Then,the precision movement of the sliding table was tested and the deflection angle in visual coordinate system was calibrated.Dispensing parameter combination of the inertia device was optimized,and dispensing consistency under specific parameters was measured.Indicator tests of this dispensing system showed that the positioning accuracy and turntable coaxial were both controlled in 20?m,and Single droplet consistency was better than 0.002 mg.Finally,dispensing experiments were carried out on 14 inertial devices and tightness of dispensing quality is checked,experimental data showed that the leakage rate was lower than 10-8 Pa·m3 /s,achieved the desired goal.