Abstract:
The present invention relates to a cleaning apparatus for printed circuit board. The cleaning apparatus includes a base, a clamping plate fixed to the base, at least one holding member, at least one cleaning roller, and a driving mechanism. The holding member is elastically supported on the base. The at least one cleaning roller is pivotably disposed on the at least one holding member respectively. The cleaning roller includes a cleaning layer attached to a surface of the cleaning roller. The clamping plate is opposite to and departs from the cleaning roller at a distance. The driving mechanism is coupled to the cleaning roller and configured for driving the cleaning roller to rotate. The cleaning apparatus can clean printed circuit board high efficiently.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a cleaning apparatus, especially to a cleaning apparatus for printed circuit boards. 
         [0003]    2. Discussion of Related Art 
         [0004]    Recently, as the electronic appliances are becoming smaller in size and diversified in function, printed circuit boards (PCBs) widely used in such electronic appliances are required to have higher circuit density and reliability. 
         [0005]    Usually, a chemical etching process is used for etching a conductive pattern on a copper clad laminate (CCL) as described below. First, a photoresist layer is applied on the CCL by screen printing method. Second, the CCL is driven to pass through an etching bath by a feed roller, thereby an etchant is sprayed simultaneously and evenly onto both an upper surface and a bottom surface of the CCL by a number of spray nozzles. As a result, the copper layer uncovered by the photoresist layer is etched and a conductive pattern is formed on the copper layer. In order to obtain a multilayer PCB, additional CCLs will be applied on the etched CCL and then through holes may be formed using a drilling method or laser ablation method. After that, through holes are plated a copper layer thereon. Finally, the chemical etching process is repeated so as to form conductive patterns on the outer CCLs. 
         [0006]    Various dust or debris produced in the above mentioned method are likely to cling on the CCLs. Such dust or debris may affect the quality of the CCLs. For example, referring to  FIG. 13 , a piece of debris of adherence layer clings on a copper layer. The debris acts as a protective layer when the copper layer is etched. As a result, the area under the debris, which is set to be etched, is not etched. This will cause short circuit between the conductive line  13  and  14 . Therefore, CCLs must be cleaned prior to perform steps such as etching on the CCLs. Accordingly, there is a desire to develop a cleaning apparatus for cleaning CCLs. 
       SUMMARY OF THEN INVENTION 
       [0007]    This and other features and advantages of the present invention as well as the preferred embodiments thereof and a cleaning apparatus in accordance with the invention will become apparent from the following detailed description and the descriptions of the drawings. 
         [0008]    In the present embodiment, a cleaning apparatus includes a base, a clamping plate fixed to the base, at least one holding member, at least one cleaning roller, and a driving mechanism. The holding member is elastically supported on the base. The at least one cleaning roller is pivotably disposed on the at least one holding member, respectively. The cleaning roller includes a cleaning layer attached to a surface of the cleaning roller. The clamping plate is opposite to and departs from the cleaning roller at a distance. The driving mechanism is coupled to the cleaning roller and configured for driving the cleaning roller to rotate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present invention in which: 
           [0010]      FIG. 1  is an isometric view of a cleaning apparatus in accordance with a first embodiment; 
           [0011]      FIG. 2  is a partial cutaway exploded view of  FIG. 1 ; 
           [0012]      FIG. 3  is a partial cutaway cross sectional view of  FIG. 1  along line III-III; 
           [0013]      FIG. 4  is a partial cutaway cross sectional view of  FIG. 1  along line IV-IV; 
           [0014]      FIG. 5  is an isometric view of a cleaning apparatus in accordance with a second embodiment; 
           [0015]      FIG. 6  is a cross sectional view of  FIG. 5  along line VI-VI; 
           [0016]      FIG. 7  is cross sectional schematic view of a cleaning apparatus in accordance with a third embodiment; 
           [0017]      FIG. 8  is an isometric view of a cleaning apparatus in accordance with a fourth embodiment; 
           [0018]      FIG. 9  is a partial cutaway cross sectional view of  FIG. 8  along line IX-IX; 
           [0019]      FIG. 10  is partial cutaway cross sectional view of  FIG. 8  along line X-X; 
           [0020]      FIG. 11  is a schematic view of a cleaning apparatus in accordance with a fifth embodiment; 
           [0021]      FIG. 12  is a schematic view of a cleaning apparatus in accordance with a sixth embodiment; and 
           [0022]      FIG. 13  is a schematic view of a printed circuit board to be cleaned. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    Referring to  FIG. 1 , a cleaning apparatus  100  in accordance with a first embodiment includes a base  10 , a clamping plate  11 , a holding member  12 , a cleaning roller  13  and a driving mechanism  14 . 
         [0024]    In this embodiment, the case  10  is a cuboid chest having a plain top plate  102  and a chamber  104  formed therein. Referring to  FIGS. 2 and 3 , a rectangle shaped opening  106  is defined in the tope plate  106 . The clamping plate  11  is fixed, for example, secured or adhered to an outer surface of the top plate  102 . The holding member  12  includes a holding portion  121  and a positioning portion  122  extending from the holding portion. A through hole  123  is formed in the holding portion  121 . Two cylinder shaped supporting portions  124  extend from the holding portion  121 . Each supporting portions  124  has a height of H. The positioning portion  122  is configured for passing through the opening  106  such that the holding member  12  can only move in a direction perpendicular to the top plate  102 . In other words, the positioning portion  122  is restricted in the opening  106 . 
         [0025]    Referring to  FIG. 3 , the holding portion  12  is elastically disposed on the top plate  102 . Specifically, the holding portion  12  is disposed on two elastic supporting members  126 . The two elastic supporting members  126  are disposed on two sides of the positioning portion  122  respectively. Elastic supporting members  126  are not limited to a special structure or type. A general criteria is that the elastic supporting members  126  can provide adequate elastic force to support the holding portion  12 . Adequate elastic force means that a height of elastic supporting members  126  is larger than H when the holding portion  12  is disposed on the two elastic supporting members  126 . In other words, an end of the supporting portion  124  does not contact with the top plate  102 . Examples of the elastic supporting members  126  include spring and underlay made of elastic materials such as rubber. In this embodiment, the elastic supporting members  126  are cylinder shaped elastic underlays made of rubber. 
         [0026]    Referring to  FIG. 4 , the cleaning roller  13  includes a roller core  130 , a shaft  132  extending from the roller core  130 , and a cleaning layer  134  attached to a surface  136  of the roller core  130 . The shaft  132  passes through the through hole  123 ; as a result, the cleaning roller  13  can rotate around the holding portion  12 . The cleaning layer  134  is made of soft materials such as fabric and fiber. Preferably, the cleaning layer  134  further includes a cleaning solution absorbed therein. The cleaning solution can be selected form the group consisting of water, alcohol, n-propanol, isopropyl alcohol, acetone, hydrochloric acid solution, vitriol acid solution, nitric acid solution, hydrogen peroxide solution and combination thereof. In this embodiment, the cleaning roller  13  is disposed above the clamping plate  11 . A printed circuit board  15  to be cleaned is disposed on a surface of the clamping plate  11 ; a distance between the cleaning roller  13  and the clamping plate  11  is less than a height of a printed circuit board  15 . As a result, the cleaning layer  134  can tightly contact with a surface of the printed circuit board  15 . 
         [0027]    The driving mechanism  14  includes a motor  142  and a strap  144 . An end of the shaft  132  is coupled to the motor through the strap  144  such that the motor  142  can drive the cleaning roller  13  to rotate. 
         [0028]    In this embodiment, the cleaning apparatus  100  uses a motor  142  to drive a cleaning roller to clean a surface of the printed circuit board  15   
         [0029]    Referring to  FIG. 5 , a cleaning apparatus  200  in accordance with a second embodiment is similar to that of the first embodiment except the clamping board  21  and the driving mechanism  24 . In this embodiment, the driving mechanism  24  includes a turnplate  242  and a handle  244 . The turnplate  242  is fixed to an end of the cleaning roller  23 . The handle  244  is fixed to a side of the turnplate  242 . The driving mechanism  24  can be driven by an operator. Alternatively, the driving mechanism  24  can also be a crank. Referring to  FIG. 6 , the clamping plate  21  includes a convex portion  211  towards to the cleaning roller  23 . A printed circuit board  25  is disposed on the clamping board  21 ; the convex portion  211  can support the printed circuit board  25  such that the printed circuit board  25  is not fully contacted with the clamping plate  21 . Therefore, abrasion damage caused by the clamping plate  21  can be reduced. 
         [0030]    Referring to  FIG. 7 , a cleaning apparatus in accordance with a third embodiment is similar to that of the first embodiment except that there are two cleaning rollers  32  and  33 . A first cleaning roller  32  includes a roller core  321  and a cleaning layer  322  attached to a surface of the roller core  321 . A second cleaning roller  33  includes a roller core  331  and a cleaning layer  332  attached to a surface of the roller core  332 . The first cleaning layer  322  includes a first cleaning solution absorbed therein. The second cleaning layer  332  includes a second cleaning solution absorbed therein. Preferably, the first cleaning solution can be resolved in the second cleaning solution. For example, the first cleaning solution can be hydrochloric acid solution and the second cleaning solution can be water. 
         [0031]    In this embodiment, the two cleaning rollers  32  and  33  rotate in a same direction. A printed circuit board  25  to be cleaned moves in a direction from the first cleaning roller  32  to the second cleaning roller  33 . A surface of the printed circuit board  25  is cleaned by the first cleaning solution of the first cleaning roller  32  at first, then the surface is cleaned by the second cleaning solution of the second cleaning roller  33 , as a result, a better cleaning result can be obtained. 
         [0032]    Referring to  FIG. 8 , a cleaning apparatus  100  in accordance with a fourth embodiment includes a base  40 , a clamping plate  41 , a holding member  42 , a cleaning roller  43 , a driving mechanism  44  and a regulating mechanism  45 . 
         [0033]    In this embodiment, the case  40  is a cuboid chest having a plain top plate  402  and a chamber  404  formed therein. The clamping plate  41  is fixed, for example, secured or adhered to an outer surface of the top plate  402 . 
         [0034]    Referring to  FIG. 9 , the holding member  42  includes a main body  420  and two arms  422  extending from two opposite sides of the main body respectively. The main body  420  includes a bearing  421  disposed therein. Each arm  422  has a through hole  424  formed therein. The two through holes  424  are parallel with each other. An elastic supporting member  426  supports each arm  422 . In this embodiment, the elastic supporting member  426  is a spring. 
         [0035]    Referring to  FIG. 10 , the cleaning roller  43  includes a roller core  431 , two shafts  433  respectively extending from two opposite ends of the roller core  43 , and a cleaning layer  422  attached to a surface of the roller core  43 . Each shaft  433  is rotatably disposed in a corresponding holding member  42 , specifically; each shaft  433  is disposed in the bearing of  421  of the holding member  42 . 
         [0036]    The driving mechanism  44  includes a motor  442  and a strap  444 . An end of one of the two shafts  433  is coupled to the motor through the strap  444  such that the motor  442  can drive the cleaning roller  43  to rotate. As described in the second embodiment, the driving mechanism  44  can also be a crank. 
         [0037]    Referring back to  FIGS. 8 and 9 , the regulating mechanism  45  includes a beam  451 , two columns  452 , and a bolt  453 . The beam  451  includes two through holes  455 . Each through hole  455  is aligned with a corresponding through hole  424  of the arm  422 . Each of the two columns  452  is fixed on the top plate  402  and extends through a corresponding through hole  424  of the arm  422  and a through hole  455  of the beam  451 . Preferably, each column  452  also extends through a corresponding elastic supporting member  426 . 
         [0038]    Two ends of the beam  451  are secured on the two columns respectively. In this embodiment, each end of the beam  451  is secured with two nuts  454 . Therefore, a height of the beam  451  can be adjusted. The bolt  453  is threadingly engaged with the beam  451  and an end  456  of the bolt  453  is in tightly contact with the main body  420  of the holding member  42 . Preferably, the end  456  is in contact with a central portion of the main body  420 . In this embodiment, if the bolt  453  is further screwed, the end  456  of the bolt  453  will apply a pressure to the main body  420  of the holding member, as a result, the holding member  42  will move to the top plate  402 . 
         [0039]    Referring to  FIG. 11 , a cleaning apparatus  500  in accordance with a fifth embodiment includes a feed roller  51 , a gathering roller  52 , a cleaning roller  53 , and a driving mechanism  54 . The driving mechanism  54  includes a motor  541  and a strap  542 . The driving mechanism  54  is configured for driving the cleaning roller  53  to rotate. A printed circuit board  56  to be cleaned is rolled on the feed roller  51 . The feed roller  51  provides printed circuit board  56  to the cleaning roller  53 . The cleaning roller  53  cleans the printed circuit board  56 ; and the cleaned printed circuit board  56  is rolled on the gathering roller  52 . The feed roller  51  and the gathering roller  52  can also be connected with a driving mechanism such as a motor.  FIG. 11  only shows a schematic view, however, the detail structure of the cleaning roller  53  and driving mechanism  54  can be learned from above embodiments. 
         [0040]    Referring to  FIG. 12 , a cleaning apparatus  600  in accordance with a sixth embodiment is similar to that of the fifth embodiment except that there are two cleaning rollers  63  and  64 . In this embodiment, a first cleaning roller  63  includes a first cleaning layer  632 ; a second cleaning roller  64  includes a second cleaning layer  642 . The first cleaning layer  632  and the second cleaning layer  642  can clean two opposite surfaces of a printed circuit board  66  simultaneously. Furthermore, the first cleaning layer  632  and the second cleaning layer  642  can absorb different cleaning solution. For example, the first cleaning layer  632  absorbs a cleaning solution suitable for a dielectric surface of the printed circuit board  66 , such as actone, isopropanol alcohol; and the second cleaning layer  642  absorbs a cleaning solution suitable for a copper surface of the printed circuit board  66 , such as hydrochloric acid solution, vitriol acid solution, nitric acid solution and hydrogen peroxide solution. 
         [0041]    Finally, it is to be understood that the above-described embodiments are intended to illustrate rather than limit the invention. Variations may be made to the embodiments without departing from the spirit of the invention as claimed. The above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention.