Abstract:
A testing apparatus and a testing method are disclosed. The testing apparatus has a testing assembly. The testing assembly includes a first plate body, a testing paper, and a second plate body. The first plate body has a plurality of pins; the testing paper includes a plurality of first through holes whose locations correspond to the plurality of pins. The second plate body connects with the testing paper and has a plurality of second through holes whose locations correspond to the first through holes for allowing the plurality of pins to pass through the corresponding through holes. A sprayer is located, beneath the second plate body and sprays flux onto the inner wall of each second through hole, and a plurality of wet marks are left on the testing paper for interpretation of the coating quality.

Description:
FIELD 
       [0001]    The present invention relates to a testing apparatus and a testing method, and especially relates to a testing apparatus and a testing method for testing the quality of a flux coating. 
       BACKGROUND 
       [0002]    As technology develops, the functions of electronic products have become more and more complex, and it is also a trend for electronic products to be compact and lightweight. However, in order to accomplish the complex functions of the electronic products, the electronic components within the electronic products have a significant increase in performance, accompanied by a noticeable increase in the quantity of pins. Therefore, the PCB (printed circuit board) layouts of electronic products have become delicate and complicated, and the welding of electronic components on the PCB has become more difficult. 
         [0003]    Before electronic components are welded to a PCB, a flux coating procedure sprays flux for removing the oxides on the surface of the PCB to prevent re-oxidation, decrease the surface tension of the solder, and increase the welding performance. Furthermore, the quantity of the flux sprayed on the PCB directly affects the reliability of the welding joint. If the sprayed quantity of flux is inadequate, an insufficient amount of solder will contact the complements accommodated in the penetrating hole. If too much flux is sprayed, built up residues of the acidic flux material will damage the PCB in the long term, causing electrical failure; in addition, overuse of flux causes waste and increases the manufacturing costs accordingly. 
         [0004]    Please refer to  FIG. 1  to understand the prior art testing assembly  100 . As shown in  FIG. 1 , the prior art testing assembly  100  comprises a PCB  80 , a base fixture  90 , and a testing paper (not shown), wherein the testing paper is attached on the PCB  80 . In  FIG. 1 , from the viewer&#39;s point of view, the stacked position (from the near side to the far side) is the base fixture  90 , the PCB  80 , and the testing paper. In general, the PCB  80  is a dummy PCB; i.e., it is an actual PCB used in real electronic products, but one without any electronic components welded to it. The plurality of holes  91  of the base fixture  90  are set according to the positions of the components&#39; pins for facilitating flux spraying. While the prior art testing assembly  100  is in a flux testing process, the flux is sprayed underneath the base fixture  90 , passes through the through hole of the PCB  80 , and leaves wet marks on the testing paper. 
         [0005]    After the flux spraying procedure is finished, a technician removes the testing paper from the PCB  80  and observes the wet marks on the testing paper to determine whether every through hole in the PCB  80  has been coated with flux or not. This testing method can identify only whether every through hole in the PCB  80  is coated with flux or not; however, the quality of the spray coating in each through hole cannot be identified. Therefore, after the welding process is accomplished, problems such as poor solder joint reliability or dewetting still occur even if every through hole in the PCB  80  was coated with flux. The cause of the above-mentioned problems is the lack of electronic components placed on the PCB  80  used in the prior art testing assembly  100 ; during the actual welding process, the pins of electronic components are accommodated in each through hole of the PCB  80 , and the pin, being inside the through hole of the PCB  80 , occasionally blocks the flux coating, which causes the quality of a flux coating of the through hole to be poor and leads to the problem of poor solder joint reliability or de wetting. 
         [0006]    To sum up, because the quality of a flux spray coating has a direct effect on the welding process and the solder joint reliability of the PCB afterwards, there is a need to provide a new testing assembly for testing the quality of a flux spray coating to overcome the problems in the prior art. 
       SUMMARY 
       [0007]    One object of the present invention is to provide a testing apparatus for testing the quality of a flux coating. 
         [0008]    Another object of the present invention is to provide a testing method for testing the quality of a flux coating. 
         [0009]    In order to achieve the abovementioned objects, the testing apparatus of the present invention comprises a testing assembly and a base, wherein the base is applied for bearing the testing assembly. The testing assembly comprises a first plate body, a testing paper, and a second plate body. The first plate body comprises a plurality of pins; the testing paper is stacked on the first plate body. The testing paper comprises a plurality of first through holes, each of which corresponds to a pin. The second plate body is stacked on a surface opposite to the surface connected to the testing paper of the first plate body. The second plate body comprises a plurality of second through holes, each of which is corresponding to a first through hole for allowing every pin to pass through the corresponding first through holes and the second through holes. After the flux has been sprayed underneath the second plate body by the sprayer, the testing paper is removed and at least one wet mark corresponding to each second through hole is left on the testing paper for interpretation; thus, the quality of a flux coating of the testing apparatus can he evaluated. 
         [0010]    According to one embodiment of the present invention, the second plate body further comprises a first surface opposite to the surface connected to the testing paper, and the plurality of pins are exposed to the first surface after the plurality of pins pass through the plurality of second through holes respectively. 
         [0011]    According to one embodiment of the present invention, the plurality of second through holes comprise a plurality of aperture sizes and/or a plurality of formats. 
         [0012]    According to one embodiment of the present invention, the base comprises a bearing surface, and the second plate body further comprises a first surface opposite to the. surface connected with the testing paper, wherein the bearing surface contacts the first surface and the bearing surface comprises at least one opening for exposing the plurality of second through holes. 
         [0013]    According to one embodiment of the present invention, when the sprayer sprays the flux underneath the base, the flux passes through the opening and is coated on an inner wall of each second through hole, such that at least one wet mark is left on the testing paper corresponding to a location of each of the second through holes for interpretation. 
         [0014]    According to one embodiment of the present invention, the base comprises at least one clamp, and the at least one clamp comprises a fixed end and a free end, wherein the fixed end is connected with the bearing surface. When the testing assembly is placed on the base, the free end touches the first plate body for fixing the testing assembly between the bearing surface and the clamp. 
         [0015]    According to one embodiment of the present invention, the wet mark is in an annular shape, and the annular shape comprises at least one opening angle θ. The quality of a flux coating is satisfactory when the at least one opening angle θ is equal to or smaller than 60°. The flux-spray coating quality is unsatisfactory when the at least one opening angle θ has a plurality of opening angles θ or the at least one opening angle θ is greater than or equal to 60°. 
         [0016]    The present invention further provides a testing method for testing the quality of a flux coating of the testing apparatus after a flux has been sprayed thereon by a sprayer. The testing method comprises the following steps: allowing each pin of the first plate body to pass through each of the first through holes of the testing paper respectively; allowing each of the pins of the first plate body to pass through each of the second through holes of the second plate body respectively; spraying the flux underneath the second plate body by the sprayer; then removing the testing paper and interpreting at least one wet mark corresponding to each second through hole left on the testing paper for evaluating the quality of the flux-spray coating of the testing apparatus. 
         [0017]    According to one embodiment of the present invention, the testing method further comprises the following steps before the sprayer sprays the flux beneath the second plate body: placing the testing assembly on the base, and fixing the testing assembly to the bearing surface by the at least one clamp. 
         [0018]    According to one embodiment of the present invention, the at least one wet mark is in an annular shape and the testing method for interpreting the at least one wet mark further comprises the following steps: the flux-spray coating quality is satisfactory when the annular shape comprises at least one opening angle θ and the at least one opening angle θ is equal to or smaller than 60°; the flux-spray coating quality is unsatisfactory when the at least one opening angle θ is greater than 60°. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The exemplary embodiment of the present invention will be understood more fully from the detailed description given below and from the accompanying drawings of the invention, which, however, should not be taken to limit the invention to the specific embodiment, but are for explanation and understanding only. 
           [0020]      FIG. 1  is the prior art of the testing assembly. 
           [0021]      FIG. 2  is an exploded view of the testing apparatus of the present invention. 
           [0022]      FIG. 3  is a schematic drawing of the testing apparatus of the present invention. 
           [0023]      FIG. 4  is a sectional schematic drawing of the present invention. 
           [0024]      FIG. 5  is a partly enlarged drawing of  FIG. 4 . 
           [0025]      FIG. 6  is a schematic drawing of the wet marks on the testing paper. 
           [0026]      FIG. 7  is a schematic drawing of the opening angle of the wet marks. 
           [0027]      FIG. 8  is the flow chart of the testing method of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    To facilitate understanding and to clarify the object, characteristics and advantages of the present invention, the following specific embodiment and figures illustrating the present invention are presented to provide a detailed description. 
         [0029]    Please refer to  FIG. 2  to  FIG. 5 , relating to one embodiment of the present invention, wherein  FIG. 2  is an exploded view of the testing apparatus of the present invention;  FIG. 3  is a schematic drawing of the testing apparatus of the present invention;  FIG. 4  is a sectional schematic drawing of the present invention;  FIG. 5  is a partly enlarged drawing of  FIG. 4 . 
         [0030]    The testing apparatus  1  of the present invention is employed for testing the quality of a flux coating of the testing apparatus  1  after a flux  70  has been sprayed thereon by a sprayer  60 . As shown in  FIG. 2  and  FIG. 3 , the testing apparatus  1  of the present invention comprises a testing assembly  10  and a base  20 , wherein the base  20  is applied for bearing the testing assembly  10 . The testing assembly  10  comprises a first plate body  11 , a testing paper  12 , and a second plate body  13 . The base  20  comprises a bearing surface  21  and at least one clamp  22 , wherein the testing assembly  10  is placed on the bearing surface  21  and the testing assembly  10  is fixed between the at least one clamp  22  and the bearing surface  21 . 
         [0031]    In this embodiment, as shown in  FIG. 2  and  FIG. 3 , the first plate body  11  is a steel plate. The first plate body  11  comprises a plurality of pins  111  and locating holes  112 . The plurality of pins  111  simulate the pins of various electronic components mounted in a PCB; therefore, the plurality of pins  111  comprise a plurality of aperture sizes and formats. Furthermore, the locations and arrangement of the plurality of pins  111  can be customized, and the arrangements shown in  FIG. 2  and  FIG. 3  are for illustration only. 
         [0032]    As shown in  FIG. 2 , the testing paper  12  is stacked on the first plate body  11 , and the testing paper  12  has a plurality of first through holes  121 , each of which corresponds to a pin  111 , for allowing the plurality of pins  111  to pass through. After the plurality of pins ill pass through a plurality of first through holes  121 , the testing paper  12  is fixed with the first plate body  11  by an adhesive tape or other proper fastening. In this embodiment, the testing paper  12  is thermal paper; however, the present invention is not limited to this. The testing paper  12  can be replaced with any material that is capable of absorbing flux. 
         [0033]    As shown in  FIG. 2 , the second plate body  13  comprises a plurality of second through holes  131 , a locating hole  132 , and a first surface  133  at the bottom, wherein the locations of the plurality of second through holes  131  are corresponding to the locations of the plurality of first through holes  121  for allowing each pin  111  to pass through the corresponding second through hole  131 . The locating hole  132  is used for aligning with the locating hole  112  of the first plate body  11 , such that the plurality of pins  111  can pass through the plurality of second through holes  131  smoothly. The hole-to-hole alignment in this embodiment is one example, but the present invention is not limited to this. 
         [0034]    Another example is to dispose a convex post on the base  20  for connecting and aligning with the locating hole  132 . The testing paper  12  is clipped in-between the first plate body  11  and the second plate body  13  for accomplishing the assembly of the testing assembly  10  of the present invention. It is noted that the plurality of second through holes  131  of the second plate body  13  is applied for simulating a condition in which the flux  70  is sprayed on various sizes of through holes; therefore, as mentioned before, identical to the pin  111 , the second through holes  131  comprise a plurality of aperture sizes and formats. Furthermore, as shown in  FIG. 4  and  FIG. 5 , after the plurality of pins  111  pass through the corresponding second through holes  131 , the plurality of pins  111  are exposed to the first surface  133  of the second plate body  13 . In this embodiment, the second plate body  13  of the present invention is a dummy for simulating an actual PCB. 
         [0035]    As shown in  FIG. 2  and  FIG. 3 , after the testing assembly  10  of the present invention is assembled, the testing assembly  10  can be placed on the base  20  of the present invention. In this embodiment, the first surface  133  of the second plate body  13  in the testing assembly  10  directly contacts the bearing surface  21  of the base  20 . As shown in  FIG. 5 , the bearing surface  21  further comprises at least one opening  211  for exposing the plurality of second through holes  131  to allow the sprayer  60  to spray the flux  70  underneath the base  20 . It is noted that, as shown in  FIG. 2 , the opening  211  in this embodiment is a plurality of openings  211 ; however, the present invention is not limited to this. As long as all of the plurality of second through holes  131  of the second plate body  13  can be exposed, there is no limitation on the number of the openings  211 . According to one embodiment of the present invention, the base  20  of the present invention is made of aluminum alloy for ensuring that the base  20  of the present invention is reusable, resistant to corrosion, and resistant to 100-degree heat, but the material of the base  20  of the present invention is not limited to this embodiment. 
         [0036]    As shown in  FIG. 2  and  FIG. 3 , in this embodiment, the at least one clamp  22  is a plurality of steel clips located at the four side edges of the bearing surface  21  for fixing the testing assembly  10  to the base  20 . As shown in  FIG. 3 , the clamp  22  comprises a fixed end  221  and a free end  222 , wherein the fixed end  221  can be connected with the bearing surface  21  by screws or other fastening elements. After the testing assembly  10  is placed on the base  20 , a technician toggles the free end  222  of the clamp  22  to cause the free end  222  to contact the testing assembly  10 ; therefore, the testing assembly  10  is fixed in-between the bearing surface  21  and the clamp  22 . Furthermore, the testing assembly  10  with various thicknesses can also be fixed in-between the bearing surface  21  and the clamp  22  by the clamp  22  to increase the suitability of the base  20 . It is noted that, in this embodiment, the free end  222  of the clamp  22  contacts a surface of the first plate body  11 , for example, the top surface, on which no pins  111  are disposed. 
         [0037]    Please refer to  FIG. 5 ,  FIG. 6  and  FIG. 7 , wherein  FIG. 6  is a schematic drawing of the wet marks on the testing paper;  FIG. 7  is a schematic drawing of the opening angle of the wet marks. 
         [0038]    As shown in  FIG. 5 , in this embodiment, after the testing assembly  10  is assembled and placed on the base  20 , the testing apparatus  1  of the present invention moves along a direction indicated by the arrow in  FIG. 5 . While the testing apparatus  1  is moving, the sprayer  60  sprays the flux  70  underneath the base  20 . The flux  70  passes through the opening  211  and coats an inner wall of each second through hole  131 , thereby leaving a plurality of wet marks  71  on the testing paper  12 , which is located between the first plate body  11  and the second plate body  13 , such wet marks  71  corresponding to each second through hole  131  (as shown in  FIG. 6 ) for allowing a technician to interpret the level of the flux  70  coating the inner wall of each second through hole  131 . 
         [0039]    As shown in  FIG. 6 , after the flux  70  spraying process has finished, each wet mark  71 ,  71   a  on the testing paper  12  is located at the outer edge of each first through hole  121 . In this embodiment, the wet marks  71 ,  71   a  are in annular shapes and the level of the flux  70  coating the inner wall of each second through hole  131  can be determined by observing the shape of each wet marks  71 ,  71   a , to determine whether the spray coating quality of the flux  70  coating the corresponding inner wall is satisfactory or unsatisfactory. 
         [0040]    As shown in  FIG. 6  and  FIG. 7 , the quality of a flux coating of the inner wall of the second through hole  131  corresponding to a wet mark  71  meets manufacturing criteria, or the quality of a flux coating is satisfactory, when o wet mark  71  on the testing paper  12  is in a closed annular shape, or when there is an opening angle θ in the annular shape of the wet marks  71  and the opening angle θ is equal to or smaller than 60° or another predetermined angle. Furthermore, when all of the wet marks  71  on the testing paper  12  are interpreted as indicating that the flux  70  coating each corresponding inner wall of the second through holes  131  meets manufacturing criteria, then there is no need to adjust the sprayer  60  to change the spraying way or the spraying direction of the flux  70 . 
         [0041]    As shown in  FIG. 6 , the quality of a flux coating of the inner wall of the second through hole  131  corresponding to the wet marks  71  fails to meet manufacturing criteria, or the quality of a flux coating is unsatisfactory, when a wet mark  71   a  on the testing paper  12  comprises an opening angle θ greater than 60° (or greater than another predetermined angle) or more than two (or another predetermined amount) opening angles and at least one of the opening angles θ is greater than 60° (or greater than another predetermined angle). In such a case, there is a need to adjust the sprayer  60  to change the spraying way or the spraying direction of the flux  70  for improving the spray coating quality of the flux  70 . 
         [0042]    The difference between the present invention and the prior art is that the testing assembly  10  of the present invention has a plurality of pins  111 , each of which is located in the corresponding second through hole  131  of the second plate body  13 . The connecting state of the testing assembly  10  of the present invention is the same as the connecting state of a PCB through hole in which the pin of an electronic component is accommodated during the welding process. Therefore, the quality of a flux coating of the PCB through hole during the manufacturing process can be represented by the quality of a flux coating of the testing assembly  10 . Furthermore, a technician can also get a broad picture of the quality of a flux coating of the various formats of pins  111  located in different aperture sizes by observing the wet marks  71 ,  71   a.  Thus, the spraying direction, the spraying way, and the spraying quantity of the flux  70  can be adjusted to the optimum conditions by technicians before the welding process. As a result, the quantity of the flux  70  coated in each PCB through hole will be sufficient and the reliability of the solder joints thereby increased. In addition, a waste of the flux  70  in the prior art caused by ensuring that every PCB through hole was coated with an adequate quantity of flux  70  such that some of the PCB through holes were coated with too much flux  70  is also avoided in the present invention. 
         [0043]    Please refer to  FIG. 2 ,  FIG. 7  and  FIG. 8  for understanding one embodiment of the testing method of the present invention, wherein  FIG. 8  is the flow chart of the testing method of the present invention. 
         [0044]    As shown in  FIG. 5 , the testing method of the present invention is applied for testing the quality of a flux coating of a testing apparatus  1  after a flux  70  has been sprayed thereon via a sprayer  60 . As shown in  FIG. 2  and  FIG. 3 , the testing apparatus  1  comprises a testing assembly  10  and a base  20 . The testing assembly  10  comprises a first plate body  11 , a testing paper  12 , and a second plate body  13 . The first plate body  11  comprises a plurality of pins  111 ; the testing paper  12  comprises a plurality of first through holes  121 ; the second plate body  13  comprises a plurality of second through holes  131  and the first surface  133 ; the base  20  comprises a bearing surface  21  with at least one opening  211  and at least one clamp  22 . As shown in  FIG. 8 , the testing method of the present invention comprises the following steps: 
         [0045]    Step S 1 : allowing each pin of the first plate body to pass through each of the first through holes of the testing paper respectively. 
         [0046]    As shown in  FIG. 2 , each of the pins  111  of the first plate body  11  passes through the first through hole  121  of the testing paper  12  respectively, wherein the first through holes  121  are set in advance and the locations of the first through holes  121  are corresponding to each of the pins  111 . In this embodiment, an adhesive tape is used for fixing the testing paper  12  to the first plate body  11 . 
         [0047]    Step S 2 : allowing each of the pins of the first plate body to pass through each of the second through holes of the second plate body respectively. 
         [0048]    As shown in  FIG. 2 , each of the pins  111  of the first plate body  11  passes through each of the corresponding through holes  131  of the second plate body  13 , and the testing paper  12  is located between the first plate body  11  and the second plate body  13 . As shown in  FIG. 4  and  FIG. 5 , every pin  111  is exposed to the first surface  133  of the second plate body  13  after passing through the second through holes  131 . 
         [0049]    Step S 3 : placing the testing assembly on the base. 
         [0050]    The testing assembly  10  is placed on the base  20 . As shown in  FIG. 2  and  FIG. 4 , in this embodiment, the first surface  133  of the second plate body  13  of the testing assembly  10  contacts the bearing surface  21 . 
         [0051]    Step S 4 : fixing the testing assembly to the bearing surface by the at least one clamp. 
         [0052]    After the testing assembly  10  is placed on the base  20 , the testing assembly  10  is fixed between the bearing surface  21  and the clamp  22  by the clamp  22  of the base  20  (as shown in  FIG. 3  and  FIG. 4 ). 
         [0053]    Step S 5 : spraying the flux underneath the second plate body via the sprayer, then removing the testing paper and interpreting at least one wet mark, which corresponds to each second through hole, left on the testing paper. 
         [0054]    As shown in  FIG. 5 , the sprayer  60  sprays the flux  70  underneath the base  20 . The flux  70  passes through the opening  211  and then coats the inner wall of each second through hole  131 , simultaneously leaving a plurality of wet marks  71  on the testing paper  12 , which is between the first plate body  11  and the second plate body  13 , corresponding to each second through hole  131  (as shown in  FIG. 6 ) for a technician to interpret the quality of a flux coating on the inner wall of each second through hole  131 . 
         [0055]    Step S 6 : removing the testing paper and interpreting the plurality of wet marks. 
         [0056]    As shown in  FIG. 6 , the wet marks  71 ,  71   a  on the testing paper  12  are located at the outer edge of each first through hole  12 . In this embodiment, the wet marks  71 ,  71   a ′ are in annular shapes and a technician can determine the quality of a flux coating of the inner wall of each second through hole  131  through observing the shapes of the wet marks  71 ,  71   a.    
         [0057]    Step S 61 : wet mark has at least one opening angle θ or not. 
         [0058]    As shown in  FIG. 6 , if the wet marks  71   a,    71   a  have at least one opening angle θ, Step S 62  is implemented. As shown in  FIG. 6 , if the wet marks  71 ,  71   a  do not have any opening angle θ, Step S 63  is implemented. 
         [0059]    Step S 62 : number of the opening angles θ is greater than a predetermined value. 
         [0060]    In this embodiment, the predetermined value is one; therefore, if the number of the opening angles θ of the wet marks  71 ,  71   a  is more than one, Step S 7  is implemented. If the number of opening angles θ of the wet marks  71 ,  71   a  is less than one, Step S 64  is implemented. 
         [0061]    Step S 63 : the flux-spray coating quality is satisfactory. 
         [0062]    As shown in  FIG. 6 , the flux  70  is evenly coating the inner wall of the second through holes  131 , corresponding to the wet mark  71 , and the quantity is adequate; i.e., the spray coating quality is satisfactory when there is no opening angle θ in one wet mark  71 , or one wet mark  71  has an opening angle θ and the opening angle θ is equal to or smaller than 60°, indicating that the quantity of flux  70  coating the inner wall of second through hole  131  is also sufficient; i.e., the spray coating quality is satisfactory. 
         [0063]    Step S 64 :θ:≧60° or θ≦60° 
         [0064]    As shown in  FIG. 6 , when the opening angle of a wet mark  71  a is greater than 60°, Step S 7  is implemented. When the opening angle of a wet mark  71   a  is smaller than 60°, Step S 63  is implemented. 
         [0065]    Step S 7 : the flux-spray coating is unsatisfactory. 
         [0066]    As shown in  FIG. 6 , the flux  70  coating the inner wall of the second through hole  131  corresponding to the wet marks  71   a  is insufficient when one wet mark  71   a  has a plurality of opening angles B or one of the opening angles θ is greater than 60°; thus the spray coating quality is unsatisfactory. Therefore, there is a need to adjust the sprayer  60  to change the spraying way or the spraying direction of the flux  70  for improving the spray coating quality of the flux  70 . 
         [0067]    It is noted that the steps of the testing method of the present invention are not limited to the above-mentioned order. As long as the objects of the present invention can be realized, the steps of the testing method can be changed. 
         [0068]    It is noted that the above-mentioned embodiments are only for illustration. It is intended that the present invention cover modifications and variations of this invention provided they fail within the scope of the following claims and their equivalents. Therefore, it will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention.