Abstract:
There is provided a laser machining apparatus for sheet-like workpieces that allows an installation area to be reduced and that may be readily controlled. The laser machining apparatus comprises a Y-table movable in X- and Y-plane directions orthogonal to a laser beam irradiated from an fθ lens, a supply reel for holding a supply-side roll in which a sheet-like workpiece is rolled in a roll and capable of supplying the sheet-like workpiece, and a take-up reel for holding a take-up side roll in which the sheet-like workpiece whose machining has been finished is rolled up in a roll and capable of taking up the sheet-like workpiece. Machining is carried out by fixing the sheet-like workpiece in the machining area on the movable table and by irradiating the laser beam while relatively moving the movable table to the laser beam. Here, at least one of the supply reel and the take-up reel is disposed on the movable table.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a laser machining apparatus for repeatedly machining a sheet-like workpiece by positioning and fixing the sheet-like workpiece on a machining area on a movable table and by relatively moving the movable table and laser machining means.  
         [0003]     2. Description of Related Art  
         [0004]     Japanese Patent Laid-Open No. 2000-246479 has disclosed a sort of laser machining apparatus comprising a movable table on which an area-to-be-machined of a lengthy flexible printed board, i.e., a sheet-like workpiece, is fixed and which is movable in three axial directions and laser beam irradiating means for irradiating a laser beam to the flexible printed board, and having further with a roll-out unit, disposed on one side of the machining apparatus, for rolling out a non-machined flexible printed board rolled up in a roll and a take-up unit, disposed on the other side of the machining apparatus, for taking up the flexible printed board whose machining has been finished so that the sheet-like workpiece forms a certain length of free loops (sag) between the machining apparatus and the roll-out unit and between the machining apparatus and the take-up unit, respectively, to allow the movable table to move during machining.  
         [0005]     However, the apparatus has had a problem that its overall installation area is large because there has to be an enough distance between the machining apparatus and the roll-out unit and between the machining apparatus and the take-up unit in order to prevent the flexible printed board from being damaged by a twist or the like caused when the movable table moves during machining.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     It is therefore an object of the invention to provide a laser machining apparatus for sheet-like workpieces which requires less installation area and which may be readily controlled.  
         [0007]     In order to solve the abovementioned problems, according to a first aspect of the invention, a laser machining apparatus for machining sheet-like workpieces comprises: 
        laser beam irradiating means installed on a bed and capable of irradiating a laser beam;     a movable table provided so as to be movable at least in plane directions (X- and Y-plane directions) orthogonal to the laser beam;     a supply-side roll holding device for holding a supply-side roll in which a sheet-like workpiece is rolled up in a roll and capable of supplying the sheet-like workpiece to the movable table; and     a take-up side roll holding device for holding a take-up side roll in which the sheet-like workpiece whose machining has been finished is rolled up in a roll and capable of taking up the sheet-like workpiece on the movable table: and     machines the sheet-like workpiece in a machining area on the movable table by fixing the sheet-like workpiece placed on the machining area on the movable table and by irradiating the laser beam thereto by the laser beam irradiating means while relatively moving the movable table and the laser beam irradiating means during machining:     wherein at least one of the supply-side roll holding device and the take-up side roll holding device is disposed on the movable table.        
 
         [0014]     According to a second aspect of the invention, the supply-side roll holding device and the take-up side roll holding device are disposed on one side of the machining area on the movable table.  
         [0015]     According to a third aspect of the invention, the laser machining apparatus further comprises moving means for holding and moving the sheet-like workpiece by a desirable distance in the take-up direction in taking up and supplying the sheet-like workpiece by the take-up side roll holding device and the supply-side roll holding device a fter machining.  
         [0016]     Structuring the laser machining apparatus as described above allows at least one space where a free loop of the sheet-like workpiece is formed to be eliminated, so that an overall installation area thereof may be reduced. Still more, the apparatus may be readily controlled because it is composed of the fewer components.  
         [0017]     Additional objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, which are best understood with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a front partial section view of a laser machining apparatus of the invention.  
         [0019]      FIG. 2  is an enlarged view of a part A in  FIG. 1 .  
         [0020]      FIGS. 3A through 3L  are drawings for explaining operations of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     The present invention will be explained below based on an embodiment thereof shown in the drawings.  
         [0022]      FIG. 1  is a front partial section view of a laser machining apparatus of the invention and  FIG. 2  is an enlarged view of a part A in  FIG. 1 .  
         [0023]     In the inventive laser machining apparatus  50 , a gate-type column  30  is fixedly installed on a bed  1 . Disposed on the column  30  are a laser oscillator  31 , a plurality of mirrors  32  (two in  FIG. 1 ), a pair of mirrors  33  and an fθ lens  34 .  
         [0024]     A linear guide  2  is disposed on the upper face of the bed  1 . The linear guide  2  allows an X-table  3  to move on the bed  1  in the X direction. A linear guide  4  is disposed on the upper face of the X-table  3 . The linear guide  4  allows a Y-table (movable table)  5  to move on the X-table  3  in the Y direction. From the structure described above, the Y-table  5  is movable in the X and Y directions with respect to the bed  1 .  
         [0025]     As shown in  FIG. 2 , a machining table  6  and a reel holder  10  are disposed on the upper face of the Y-table  5 . A channel  6   m  having a lateral width wider than that of a sheet-like workpiece (hereinafter referred to simply as a “workpiece”) w is formed in the Y direction at the under face of the machining table  6 . A plurality of holes connected with a hollow section not shown within the table are formed on the upper face of the machining table  6  and the hollow section not shown within the table is connected to a vacuum source not shown. Disposed on the reel holder  10  are a supply reel  11 , a take-up reel  12 , guide rollers  13 ,  14  and  15 , clampers  16  and  17 , a return roller  18  and a workpiece conveying device (moving means)  20 .  
         [0026]     The supply reel  11  is disposed on the reel holder  10  so that a lower end  11   b  of a shaft thereof is positioned on a level below an upper end  13   t  of the guide roller  13  and is rotatable by means of a motor not shown. That is, the supply reel  11  holds a supply-side roll  40  in which the non-finished workpiece w is rolled up in a roll and is capable of supplying the workpiece w when it is driven by a motor not shown (supply-side roll holding device).  
         [0027]     The take-up reel  12  is disposed so that a lower end of a take-up side roll  41  of the workpiece w which has been taken up is positioned on a level above a lower end  14   b  of the guide roller  14  and is rotatable by means of a motor not shown. That is, the take-up reel  12  holds the take-up side roll  41  in which the finished workpiece w is taken up in a roll and is capable of taking up the workpiece w when it is driven by the motor not shown (take-up side roll holding device).  
         [0028]     The rotatable guide roller  13  is supported by the reel holder  10  so that an upper end  13   t  thereof is positioned on a level above the surface of the machining table  6 . The rotatable guide rollers  14  and  15  are supported by the reel holder  10  so that lower ends  14   b  and  15   b  thereof are positioned on a level under the bottom face of the channel  6   m.    
         [0029]     The clampers  16  and  17  are composed of receptacles  16   u  and  17   u  and pressers  16   p  and  17   p  disposed so as to face to the receptacles  16   u  and  17   u . These components, except of the receptacle  17   u , are movable in the Z direction (vertical direction in the figure) respectively by means not shown. A standby position of the receptacle  16   u  is its lowering end and at this time, its upper face is positioned on a level lower than the surface of the machining table  6 . When it is located at its raising end, its upper face is positioned on the same level with the upper end  13   t  of the guide roller  13 . A lowering end of the presser  16   p  is located on a level far below the upper face of the receptacle  16   u  located at its standby position so that the lower face of the presser  16   p  can press the upper face of the receptacle  16   u  located at its standby position. Still more, the lowering end of the presser  17   p  is located on a level far below the upper face of the receptacle  17   u  so that the lower face of the presser  17   p  can press the upper face of the receptacle  17   u.    
         [0030]     The rotatable return roller  18  is supported by the reel holder  10  so that its upper end  18   t  is positioned on the same level with the upper end  13   t  of the guide roller  13 .  
         [0031]     The workpiece conveying device  20  may be moved and positioned in the X direction with respect to the reel holder  10  by means not shown such as a motor and a guide rail mechanism. The workpiece conveying device  20  supports a clamper  21 . The clamper  21  is composed of a presser  21   p  and a receptacle  21   u  movable in the vertical direction. A standby position of the receptacle  21   u  is the position where its upper face is on a level lower than the upper face of the machining table  6  and its raising end is on the same level with the upper end  13   t  of the guide roller  13  and the upper end  18   t  of the return roller  18  as shown in  FIG. 2  by solid lines. A standby position of the presser  21   p  is the position where the lower end thereof is located on a level above the upper end  13   t  of the guide roller  13  and the upper end  18   t  of the return roller  18  and its lowering end is located on a level far below the upper end of the receptacle  21   u  located at its raising end so that the lower face thereof can press the upper face of the receptacle  21   u  located at its raising end. It is noted that the standby position of the workpiece conveying device  20  in the X direction is located at the left end of the move shown by the solid lines in the figure and the right end of the move is shown by dotted lines in the figure.  
         [0032]     Next, operations of the laser machining apparatus  50  will be explained with reference to  FIG. 3 .  FIG. 3  is an explanatory diagram showing the inventive operation of the laser machining apparatus  50 .  
         [0033]     Prearrangement operations will be explained at first.  
         [0034]     The supply-side roll  40  is supported by the supply reel  11 , the workpiece w is wound around the return roller  18  and is then passed through the channel  6   m  of the machining table  6  to fasten its end to the take-up reel  12  (the take-up-side roll  41 ) as shown in the figures while opening all the clampers  16 ,  17  and  21  beforehand (by positioning the receptacles  16   u  and  21   u  to their standby position and the pressers  16   p ,  17   p  and  21   p  to their raising end, respectively).  
         [0035]     Next, the presser  16   p  is put into operative, i.e., is lowered, to fasten the workpiece w between it and the receptacle  16   u  while applying clockwise torque to the supply reel  11  and the take-up reel  12  as shown in  FIG. 3A . Next, the presser  17   p  is put into operative, i.e., is lowered, to fasten the workpiece w between it and the receptacle  17   u . As a result, the workpiece w is fixed on the surface of the machining table  6  without looseness. A vacuum source not shown is put into operative in this state to adhere the workpiece w closely on the surface of the machining table  6 .  
         [0036]     In succession, machining is carried out. That is, the laser oscillator  31  is put into operative and a laser beam emitted from the laser oscillator  31  is led to the mirrors  33  via the mirrors  32 . Then, the laser beam is positioned by the galvanic scanner mirror  33  and is put into the workpiece w after vertically aligning an optical axis of the laser beam by the fθ lens  34  to machine the workpiece w. After machining an area determined by the fθ lens  34 , machining of a next area is carried out by moving the X-table  3  or the Y-table  5 .  
         [0037]     Next, steps for moving the workpiece after machining will be explained.  
         [0038]     After machining, the vacuum source not shown is stopped and then the presser  16   p  is raised as shown in  FIG. 3B .  
         [0039]     Next, the clamper  21  is put into operative, i.e., the presser  21   p  is lowered after raising the receptacle  21   u  to hold the workpiece w by the presser  21   p  and the receptacle  21   u  as shown in  FIG. 3C .  
         [0040]     Next, the presser  17   p  is raised as shown in  FIG. 3D . As a result, the workpiece w is positioned on a level of the upper end  13   t  of the guide roller  13  and the upper end  18   t  of the return roller  18 .  
         [0041]     In this state, the workpiece conveying device  20  is moved to the right in the figure by a desirable distance as shown in  FIG. 3E . It is noted that in this state, the machined workpiece w is taken up by the take-up reel  12  while supplying the workpiece w by the supply reel  11 .  
         [0042]     Next, the receptacle  16   u  is moved to its raising end as shown in  FIG. 3F  and then the presser  16   p  is lowered to hold the workpiece w by the clamper  16  as shown in  FIG. 3G .  
         [0043]     Next, the clamper  21  is released as shown in  FIG. 3H . At this time, the presser  21   p  is moved to its raising end and the receptacle  21   u  is moved to the position where its upper face does not contact with the workpiece w and also with the upper face of the machining table  6 . Then, the workpiece conveying device  20  is returned to its standby position as shown in  FIG. 3I .  
         [0044]     Next, the receptacle  21   u  is positioned to its standby position as shown in  FIG. 3J  and then the presser  17   p  is lowered as shown in  FIG. 3K  to hold the workpiece w by the clamper  17 .  
         [0045]     Then, the clamper  16  is released as shown in  FIG. 3L .  
         [0046]     After that, the receptacle  16   u  is positioned to its standby position and the presser  16   p  is lowered to hold the workpiece w by the clamper  16  (see  FIG. 3A ). Then, the vacuum source not shown is put into operative to adhere the workpiece w closely to the machining table to carry out next machining. These steps are repeated in the same manner thereafter.  
         [0047]     During the steps and machining described above, the motor for rotating the supply reel  11  and the take-up reel  12  is driven with torque of a range that causes no ill-effect on the workpiece w and is controlled so as to apply a tensile force to the workpiece w so that the workpiece causes no looseness. Note that it is possible to arrange so that a tensile force is applied to the workpiece w so that the workpiece w causes no looseness by urging the guide rollers  13  and  14  or the return roller  18  in predetermined directions by springs or the like.  
         [0048]     As described above, the inventive laser machining apparatus  50  for sheet-like workpieces allows the space where a free loop of the sheet-like workpiece is formed to be eliminated and thereby allows an overall installation area of the laser machining apparatus  50  to be decreased. Still more, it may be readily controlled because it requires fewer components.  
         [0049]     Still more, since the supply reel  11  and the take-up reel  12  are disposed on one side on the Y-table  5 , the overall installation area of the laser machining apparatus  50  may be decreased as compared to the case of disposing them on the both sides of the Y-table  5 .  
         [0050]     It is noted that although the case of disposing both the supply reel  11  and the take-up reel  12  on the Y-table  5  has been explained in the embodiment described above, at least one free loop may be reduced by disposing at least one of the supply reel  11  and the take-up reel  12  on the Y-table  5 . Accordingly, the overall installation area of the laser machining apparatus  50  may be reduced as compared to the conventional one.  
         [0051]     While the preferred embodiments have been described, variations thereto will occur to those skilled in the art within the scope of the present inventive concepts which are delineated by the following claims.