Patent Publication Number: US-2021178421-A1

Title: Viscous liquid dispensing method using three-dimensional scanner

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation of International Application No. PCT/KR2019/011006, filed on Aug. 28, 2019, which claims the priority benefits of Korea Application No. 10-2018-0102068, filed on Aug. 29, 2018. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a viscous liquid dispensing method using a three-dimensional scanner, and more particularly, to a viscous liquid dispensing method using a three-dimensional scanner, allowing a three-dimensional shape of a work, to which a viscous liquid is to be dispensed, to be identified using the three-dimensional scanner, and the viscous liquid to be dispensed to the work using the identified result. 
     Description of Related Art 
     In a semiconductor process or an electronic product manufacturing process, a process of dispensing a viscous liquid, such as an adhesive, to a correct position with a correct volume is very important. When there is an error in the dispensing position and volume of the viscous liquid, defects may occur in the product. 
     In particular, when the viscous liquid is dispensed to a synthetic resin work, it is important to control the dispensing position and volume. As the demand for higher specifications in products increases, the position to which the viscous liquid is dispensed and the width of the viscous liquid to be dispensed are required to be accurate enough to be processed within an error of about several tens to several hundreds of micrometers. However, in the case of a synthetic resin work, dimensional errors of several tens of micrometers or more are easily generated for each work due to the characteristics of a manufacturing process in which injection molding is used. When an injection molding work is manufactured in a very sophisticated manner to prevent such errors, there is a problem that process costs are dramatically increased. 
     When a viscous liquid dispensing process may be performed by considering shape or dimensional errors that may occur due to work characteristics, as in a synthetic resin work, and controlling a viscous liquid dispensing path or position while responding to such errors, a defect rate may be remarkably reduced and productivity may be improved. In particular, even in the case of a synthetic resin work, high quality and precise manufacturing are not required for the dispensing process, in such a way that manufacturing costs of the work itself may be significantly reduced. 
     There is a need for a viscous liquid dispensing method using a three-dimensional scanner, which is capable of accurately dispensing a viscous liquid according to the shape of each work by effectively considering errors in the individual shape and dimension of the work, to which the viscous liquid is to be dispensed, as described above. 
     SUMMARY 
     Technical Problem 
     The present disclosure is directed to providing a viscous liquid dispensing method using a three-dimensional scanner, which is capable of individually measuring the shape and dimension of a work, to which a viscous liquid is to be dispensed, and dispensing the viscous liquid to a correct position with a correct volume using the measured result. 
     Solution to Problem 
     According to an aspect of the present disclosure, there is provided a viscous liquid dispensing method using a three-dimensional scanner, in which a viscous liquid is dispensed to a work by using a pump, the method comprising (a) obtaining three-dimensional shape data for an area of a work, to which the viscous liquid is to be dispensed, and surroundings of the area by scanning at least a portion of the work with a three-dimensional scanner, (b) calculating, by a control unit, a dispensing path to which the viscous liquid is to be dispensed using the three-dimensional shape data for the work obtained in step (a), and (c) dispensing the viscous liquid to the work while moving the pump along the dispensing path, which is calculated by the control unit in step (b), using a pump moving unit. 
     Advantageous Effects 
     A viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure has the effect of improving the quality of a viscous liquid dispensing process by allowing a viscous liquid to be dispensed to a correct position of a work. 
     A viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure has the effect of indirectly lowering manufacturing costs of a work even when there are some errors in the shape and dimension of the work by dispensing a viscous liquid using a method that can compensate for the errors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a configuration diagram of a dispenser that is used for implementing an example of a viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure. 
         FIG. 2  is a diagram illustrating an example of a work to which a viscous liquid is to be dispensed by the viscous liquid dispensing method using a three-dimensional scanner according to an embodiment of the present disclosure. 
         FIGS. 3 and 4  are cross-sectional views taken along line III-III and line IV-IV, respectively, for partial areas of the work shown in  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, an example of a viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure will be described with reference to the accompanying drawings. 
       FIG. 1  is a configuration diagram of a dispenser that is used for implementing an example of the viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure, and  FIG. 2  is a diagram illustrating an example of a work to which a viscous liquid is to be dispensed by the viscous liquid dispensing method using a three-dimensional scanner according to an embodiment of the present disclosure. 
     First, the configuration of the dispenser, which is used for implementing an example of the viscous liquid dispensing method using a three-dimensional scanner according to the present disclosure, will be described with reference to  FIG. 1 . 
     A work  10  having a shape as shown in  FIG. 2  is supplied by being placed on a work transfer unit  600 . The work transfer unit  600  transfers the work  10  in a horizontal direction. 
     A three-dimensional scanner  100  and a pump  300  are disposed above the work transfer unit  600 . 
     The three-dimensional scanner  100  is moved in the horizontal direction and a vertical direction by a scanner moving unit  200 . When the scanner moving unit  200  moves the three-dimensional scanner  100  to a position close to a major part of the work  10 , the three-dimensional scanner  100  scans the work  10  and obtains three-dimensional shape data for the work  10 . Various known configurations may be used for the three-dimensional scanner  100 . In the present embodiment, a case will be described as an example, in which the three-dimensional scanner  100  obtains a three-dimensional shape of a corresponding area by capturing an image of the work  10  at high speed using a digital micromirror device (DMD) with digital light processing (DLP) technology. 
     When the scanner moving unit  200  moves the three-dimensional scanner  100  to a position at which three-dimensional shape data needs to be obtained, the three-dimensional scanner  100  scans the work  10  three-dimensionally and obtains the three-dimensional shape data. 
     When the three-dimensional scanning for the work  10  is completed, the work transfer unit  600  transfers the work  10  to a space below the pump  300 . 
     A pump moving unit  400  moves the pump  300  in the horizontal direction and the vertical direction with respect to the work  10  on the basis of the three-dimensional shape data, and the pump  300  dispenses the viscous liquid through a nozzle. In the case of the present embodiment, the pump moving unit  400  controls an angle of the pump  300  with respect to the work  10  by tilting the pump  300 . 
     A control unit  500  controls operations of the three-dimensional scanner  100 , the pump  300 , the scanner moving unit  200 , the pump moving unit  400 , and the work transfer unit  600 . 
     Hereinafter, a process of dispensing a viscous liquid to the work  10  by the viscous liquid dispensing method using the three-dimensional scanner  100  of the present embodiment, in which the dispenser configured as described above is used, will be described. 
     In the present embodiment, a process of dispensing an epoxy adhesive as the viscous liquid to a synthetic resin injection-molded work having a quadrangular frame shape as shown in  FIG. 2  will be described. 
     In the case of the work  10  having a form of a synthetic resin injection-molded work, dimensional and shape errors of several tens of micrometers or more are easily generated due to characteristics of a synthetic resin and characteristics of an injection molding process. In addition, even in injection-molded works manufactured by the same process using the same mold, each work  10  is often slightly different in size and shape. 
     A process of dispensing a viscous liquid to the work  10  having the above-described form will be described. 
     First, at least a portion of the work  10  is scanned by the three-dimensional scanner  100  to obtain three-dimensional shape data for an area, to which the viscous liquid is to be dispensed, and surroundings of the area (step (a)). 
     The work  10  is placed below the three-dimensional scanner  100  by the work transfer unit  600 . The area to which the viscous liquid is to be dispensed and an area around the area are scanned three-dimensionally by the three-dimensional scanner  100  while moving the three-dimensional scanner  100  with the scanner moving unit  200 . All areas to which the viscous liquid is to be dispensed may be three-dimensionally scanned or only a partial area may be three-dimensionally scanned. When DMD technology is used, hundreds of images or more are captured in one second to obtain the three-dimensional shape data, and thus a very fast operation is possible. The process of obtaining the three-dimensional shape data is performed only for a partial area of the work  10  in order to further increase the operation speed. In the case of the present embodiment, a case in which three-dimensional scanning is performed only on four corner portions  13  (as shown in dotted lines in  FIG. 2 ) of the work  10  having a quadrangular frame shape will be described as an example. 
     The change in shape at the four corner portions  13  of the work  10  is relatively large due to the injection molding process. Since the result of dispensing the viscous liquid in these portions greatly affects the quality of the entire process, three-dimensional scanning is performed on the quadrangular corner portions. 
     The three-dimensional shape data obtained by the three-dimensional scanner  100  is transmitted to the control unit  500 . The control unit  500  calculates a dispensing path in which the viscous liquid is to be dispensed using the three-dimensional shape data for the work  10  obtained in step (a) (step (b)). 
     The control unit  500  may calculate the dispensing path using various methods. Various dispensing path calculation methods according to the structure and characteristics of the work  10  are programmed and performed by the control unit  500 . 
     In the present embodiment, the control unit  500  calculates the dispensing path using an edge shape of the work  10 . The control unit  500  extracts portions of edges  11  and  12 , at which surfaces meet, from the shape of the work  10  using the shape data obtained by the three-dimensional scanner  100 . The dispensing path may also be calculated along paths of the edges. For example, it is possible to set a path maintaining a reference distance inward with respect to an outer edge  12 , among the edges  11  and  12  of the work  10  shown in  FIGS. 2 to 4 , as the dispensing path. For example, the control unit  500  may set a point away from the outer edge  12  inward by 1 mm to be the dispensing path. Alternatively, it is possible for the control unit  500  to extract an inner edge  11  and the outer edge  12  of the work  10  shown in  FIGS. 2 to 4  and calculate a point between the two edges  11  and  12  as the dispensing path. In the case of the present embodiment, a case in which the control unit  500  sets an intermediate point that is a half of a width W between the inner edge  11  and the outer edge  12  as the dispensing path will be described as an example. In addition to the above-described method, the control unit  500  may calculate the dispensing path in various ways according to the characteristics of the work  10  and needs in the process. 
     When the control unit  500  completes the calculation of the dispensing path for the four corner portions  13  of the work  10  having a quadrangular frame shape as described above, the control unit  500  may also calculate a dispensing path for the remaining portions of the work  10 . When errors in shapes of portions corresponding to four sides are not great unlike the four corner portions  13  of the quadrangular frame, the control unit  500  may set a dispensing path corresponding to the four sides using the shape data for the work  10  stored in advance. It is also possible for the control unit  500  to set a dispensing path numerically corresponding to the four sides by a method of connecting dispensing paths for the four corner portions  13 . In this case, end portions of the dispensing paths of the four corner portions  13  may be connected by a straight line or a curved line reflecting a predetermined curvature, or it is also possible to set the dispensing path by interpolating a section between the end portions using the shape data for the four corner portions  13 . The control unit  500  may calculate a dispensing path for a section between areas scanned by the three-dimensional scanner  100  in various ways as described above. 
     Meanwhile, the control unit  500  may three-dimensionally calculate a dispensing path. That is, the control unit  500  considers the height of the work  10  along a dispensing path in addition to a path moving on a plane and calculates the dispensing path, through which the nozzle of the pump  300  passes, in such a way that three-dimensional coordinates are connected. 
     As described above, when the calculation of the dispensing path by the control unit  500  is completed, in response to the command of the control unit  500 , the pump  300  dispenses a viscous liquid to the work  10  while being moved along the dispensing path by the pump moving unit  400  (step (c)). At this point, the control unit  500  controls such that the pump  300  dispenses the viscous liquid to the work  10  while being moved three-dimensionally by the pump moving unit  400  in such a way that a distance between the nozzle of the pump  300  and the work  10  is maintained constant. Accordingly, the distance between the nozzle and a surface of the work  10  to which the viscous liquid is dispensed is maintained constant, thereby improving the quality of a dispensing process. 
     When an angle between the nozzle of the pump  300  and the surface of the work  10  is maintained as a right angle by the pump moving unit  400  in performing the process of dispensing the viscous liquid to the work  10  as described above, the quality of the dispensing process may be further improved. 
     To this end, a process of obtaining information about an angle of the surface of the work  10  along the dispensing path is required. When the dispensing path is calculated in step (b), the control unit  500  calculates an angle of the surface of the work  10  at a position corresponding to the dispensing path using the shape data for the work  10  obtained in step (a) (step (d)). In the case in which only a portion of the work  10  is three-dimensionally scanned as described above, the dispensing path between the scanned areas is numerically calculated by a method such as using reference shape data for the work  10  stored in advance or interpolating the angle of the surface of the work  10  calculated in the scanned area. 
     In the case in which the control unit  500  calculates the angle of the surface of the work  10  in step (d) as described above, when the viscous liquid is dispensed in step (c), the viscous liquid is dispensed while controlling the angle of the pump  300  by the pump moving unit  400  in such a way that the angle between the nozzle of the pump  300  and the surface of the work  10  is maintained as a right angle. It is preferable that the viscous liquid is dispensed in a state in which the nozzle of the pump  300  and the surface of the work  10  are perpendicular to each other, but in some cases, it is also possible to dispense the viscous liquid while maintaining an angle other than 90° constant. 
     As described above, according to the present disclosure, since the dispensing may be performed while controlling the angle of the pump  300  according to the angle of the surface of the work  10 , it is possible to dispense a viscous liquid to a correct position with a correct volume even for the work  10  formed to have a three-dimensional curved surface, and even when there are dimensional errors, shape errors, and processing errors on the surface of the work  10 , on which the dispensing is performed, by considering these errors, the viscous liquid dispensing process may be accurately performed. In addition, even in a case in which the work transfer unit  600  on which the work  10  is placed or a work mounting tray which is disposed between the work  10  and the work transfer unit  600  is inclined, when the viscous liquid is dispensed in consideration of the angle of the work  10  as described above, the quality of the dispensing process may be improved. 
     As described above, when the shape data for the work  10  is obtained by the three-dimensional scanner  100  in step (a), it is also possible for the pump  300  to dispense the viscous liquid while changing the dispensing volume along the dispensing path by considering the shape of the work  10 . 
     To this end, the control unit  500  calculates a dispensing amount of the viscous liquid to be dispensed to the work  10  along the dispensing path, which is calculated in step (b), before step (c) is performed (step (e)). 
     For example, the control unit  500  may calculate the dispensing amount of the viscous liquid in a manner of calculating the width W and a depth D of a space between the two edges  11  and  12  of the work  10  as shown in  FIGS. 3 and 4 , increasing the dispensing amount when the width W and the depth D are greater than reference values, and decreasing the dispensing amount when the width W and the depth D are less than the reference values. 
     As described above, in the case in which the control unit  500  calculates the dispensing amount of the viscous liquid in step (e), when step (c) is performed, the viscous liquid is dispensed as much as the calculated dispensing amount of the viscous liquid. 
     As a typical method of controlling the dispensing amount of the viscous liquid, a method of fixing one of a moving velocity of the pump  300  and a flow rate of the viscous liquid, which is dispensed through the nozzle of the pump  300 , and controlling the remaining one thereof is used. In the case of the present embodiment, a method of fixing the moving velocity of the pump  300  and controlling the flow rate of the viscous liquid dispensed by the pump  300  is used. The flow rate of the viscous liquid dispensed through the nozzle is controlled by moving the pump  300  at a constant velocity using the pump moving unit  400 . When the piezoelectric pump  300  is used, the flow rate of the viscous liquid may be controlled by controlling a period, in which a valve rod of the piezoelectric pump  300  is raised and lowered, by the control unit  500 . 
     As described above, various advantages may be obtained by differently controlling the amount of viscous liquid dispensed for each work  10  in consideration of the shape data for the work  10 . The process costs of processing or manufacturing the work  10  may be reduced. Even when the dimension accuracy of the work  10  is not high, the viscous liquid is dispensed in consideration of the actual shape and dimension of the work  10  in the operation of dispensing the viscous liquid, in such a way that it is possible to reduce costs required for the manufacturing process of the work  10  for manufacturing the work  10  with high accuracy. Even for the work  10  to be treated as a defective work because there is an error in the dimension and shape of the work  10 , by dispensing the viscous liquid in consideration of such dimensional or shape error, it is possible to treat the work  10  as a good work without treating the work  10  as a defective work in the process. In this way, the yield of the entire product manufacturing process may be improved. 
     For example, it may be impossible for another part to adhere to the work  10  due to a shape error of the work  10 , or even when the adhesion is made, the adhesion between the work  10  and the part may not be achieved in some sections, and a gap may be generated between the work  10  and the part, but even in this case, by additionally dispensing and curing an adhesive in consideration of the shape error of the work  10 , the gap that may be generated between the work  10  and the part may be filled with the adhesive, thereby preventing defects. 
     Even when the position and direction of the pump  300  are controlled and the dispensing amount is controlled in consideration of the three-dimensional shape of the work  10  as described above, in some cases, it may be sometimes difficult to accurately control the volume of the dispensed viscous liquid. In general, as time passes and temperature changes, characteristics of the viscous liquid change and operating characteristics of the pump  300  also change, and thus an error may exist in the dispensing result even when the dispensing is performed with the same viscous liquid and pump  300 . 
     In this case, as will be described below, the error may be corrected through a method of inspecting the dispensing result using the three-dimensional scanner  100  to determine whether there is a defect, and adding the dispensing amount of the viscous liquid with the pump  300  when the dispensed amount of the viscous liquid is insufficient. 
     When the process of dispensing the viscous liquid to the work  10  is completed through step (c), the work transfer unit  600  transfers the work  10  to the space below the three-dimensional scanner  100  again. The scanner moving unit  200  moves the three-dimensional scanner  100  to the area of the work  10 , to which the viscous liquid is dispensed, and the three-dimensional scanner  100  scans the result of dispensing of the viscous liquid performed in step (c) and obtains three-dimensional shape data for the work  10  to which the viscous liquid is dispensed (step ( 0 ). 
     The control unit  500  inspects the result of dispensing of the viscous liquid performed in step (c) using the three-dimensional shape data obtained in step ( 0  (step (g)). 
     When it is determined that the dispensing amount is insufficient as a result of inspecting the result of dispensing of the viscous liquid while performing step (g), the control unit  500  calculates a dispensing path to which the viscous liquid is to be added and a dispensing amount. 
     The work transfer unit  600  transfers the work  10  to the space below the pump  300  again, and the control unit  500  additionally dispenses the viscous liquid to the work  10  according to the result of step (g) while moving the pump  300  using the pump moving unit  400  (step (h)). 
     In this manner, the result of dispensing of the viscous liquid may be inspected by the three-dimensional scanner  100 , or in some cases, the dispensing amount of the viscous liquid may be corrected. In this manner, the quality of the dispensing process may be further improved, and also, the defect rate may be reduced. 
     In some cases, it is also possible to perform the viscous liquid dispensing method using the three-dimensional scanner  100  of the present disclosure in a manner of dispensing the viscous liquid less than a set volume while performing step (c), and then sequentially performing the steps (f), (g), and (h) to more accurately control the dispensing volume of the viscous liquid. 
     Although the present disclosure has been described with reference to the preferred examples, the scope of the present disclosure is not limited to the form described and illustrated above. 
     For example, it was previously described that only four corners of the work  10  having a quadrangular frame shape are scanned with the three-dimensional scanner  100  in step (a) and the space between the scanned areas is calculated numerically, but in some cases, it is also possible to obtain three-dimensional shape data by performing step (a) for all areas along the dispensing path. 
     Further, it was previously described that the angle of the surface of the work  10  is calculated in step (d) and the dispensing is performed while controlling the angle of the pump  300  in consideration of the angle of the surface of the work  10 , but in some cases, depending on the characteristics of the work  10 , it is also possible to perform step (c) while fixing the angle of the pump  300  without considering such an angle. 
     Further, it was previously described that the dispensing path is calculated using the edges  11  and  12  of the work  10 , but it is also possible to calculate the dispensing path using criteria other than edges. For example, a line that will be a reference of the dispensing path may be previously marked on the work  10  using a laser or the like, and the control unit  500  may calculate the dispensing path on the basis of the line. In step (b), the control unit  500  may calculate the dispensing path using various methods other than the above-described methods in consideration of the characteristics of the work  10 . 
     Further, it was previously described that the process of three-dimensional scanning and inspecting the dispensing result is performed in the steps (f) and (g), and the process of additionally dispensing is performed in step (h), but it is also possible to perform a viscous liquid dispensing method using the three-dimensional scanner  100 , in which the steps ( 0  to (h) are not performed. 
     Meanwhile, a portion corresponding to the corner of the quadrangular frame and a portion at which surfaces meet at four sides of the quadrangular frame were described by expressing as the corner and the edge, respectively, for classification.