Patent Publication Number: US-2021178517-A1

Title: Laser Apparatus With Synchronous Light Path Delay

Description:
This application claims the priority benefit of Taiwan patent application number 108145783 filed on Dec. 13, 2019. 
     FIELD OF THE INVENTION 
     The present invention relates to the field of laser and in particular to a laser apparatus with the adjustment of the laser light path. 
     BACKGROUND OF THE INVENTION 
     The traditional laser machining machine such as the gantry-type laser machining machine uses a moving mechanism like a gantry-type mechanism to move a laser machining head two-dimensionally to be aligned with a fixed workpiece under the laser machining head for laser machining. However, this traditional technique will cause the change of the traveling distance of the laser beam traveling from the laser source to the laser machining head. Consequently, the focus of the laser beam emitted from the laser machining head cannot be kept focusing on the surface of the workpiece or the laser beam arriving on the surface of the workpiece has an uneven spot size. Therefore, the different effects of the machining are incurred. 
     As for another traditional laser machining machine, the laser machining head is disposed above and aligned with the workpiece on the platform at a fixed height. The platform is driven to move two-dimensionally under the laser machining head in which the laser machining head is held still to keep the laser beam to focus on the surface of the workpiece. However, this traditional machine requires a large footprint, which is not proper for the machining requirements in a small space. 
     How to provide a stable laser beam suitable for the current gantry-type laser machining machine to machine the workpiece is the target which the inventor and the people in this field want to achieve. 
     SUMMARY OF THE INVENTION 
     One objective of the present invention is to provide a laser apparatus with light path delay which can synchronously adjust the light path. The laser apparatus has a laser path adjustment unit which can synchronously adjust the delay distance of the light path to compensate the total moving distance of the machining head such that the focusing condition is maintained during the movement of the machining head. 
     Another objective of the present invention is to provide a laser apparatus with light path delay which can be separated into two parts, the first bed and the second bed, for installation. The gantry-type machine is installed on the first bed and the laser path adjustment unit of the laser source is installed on the second bed. Besides, different laser sources can be installed on the second bed depending on different workpiece materials and machining requirements to meet the customized demand of various laser machining. 
     Yet another objective of the present invention is to provide a laser apparatus with light path delay in which the gantry-type machine and the laser path adjustment unit can both be installed on a single bed to meet the requirement of a compact or limited space. 
     To achieve the above objectives, the present invention provides laser apparatus with synchronous light path delay, which comprises a gantry-type machine, a source reflection assembly, and a laser path adjustment unit. The gantry-type machine has a first moving module and a second moving module movably connected to the first moving module. The second moving module is provided with a moving reflector disposed corresponding to a machining head. The machining head moves with the first moving module and the second moving module. The source reflection assembly is disposed corresponding to the moving reflector. The laser path adjustment unit has a laser source and a light path adjustment module. The light path adjustment module is disposed corresponding to the source reflection assembly. The laser source emits a laser beam which goes through the light path adjustment module and the source reflection assembly, then, travels to the machining head through the moving reflector. The light path adjustment module has a guiding part and a return reflection assembly. The return reflection assembly moves synchronously with the machining head and reciprocates on the guiding part over an adjustment distance to match the movement of the machining head. 
     The above-mentioned first moving module is an X-direction moving module; the second moving module is a Y-direction moving module. 
     The above-mentioned machining head has a third moving module which is movably connected to the second moving module; the third moving module is a Z-direction moving module. 
     The above-mentioned machining head has a beam input end, at least one beam output end, and a switch device. At least one beam output end comprises a first beam output end and a second beam output end. 
     The above-mentioned source reflection assembly comprises a first reflector, a second reflector, and a third reflector. The first reflector is disposed corresponding to the laser source and the second reflector. The second reflector and the third reflector are disposed corresponding to the return reflection assembly. The third reflector is disposed corresponding to the moving reflector. 
     The above-mentioned return refection assembly, the first reflector, the second reflector, and the third reflector are reflecting mirrors. 
     The above-mentioned gantry-type machine and the laser path adjustment unit are connected to a control unit. 
     The above-mentioned total moving distance of the machining head, which is defined by the movements of the first moving module and the second moving module; where as the adjustment distance is half of the total moving distance of the machining head. 
     The above-mentioned total moving distance of the machining head, which is defined by the movements of the first moving module, the second moving module, and the third moving module; where as the adjustment distance is half of the total moving distance of the machining head. 
    
    
     
       BRIEF DESCRIPTION OF DRAWING 
       The following drawings are used to make the present invention more easily to be understood; they will be detailed in the description and constitute part of the embodiments. By means of the embodiments in the description accompanied with the corresponding drawings, the embodiments of the present invention and the theory of operation thereof can be explained in detail. 
         FIG. 1  is a schematic view of the separate installations of the gantry-type machine and the laser path adjustment unit of the present invention; 
         FIG. 2  is a cross-sectional view of  FIG. 1 ; 
         FIG. 3  is a schematic view of the gantry-type machine and the laser path adjustment unit of the present invention connected to a control unit; 
         FIGS. 4A-4E  are top views of the various operating positions of the present invention; 
         FIG. 5  is a schematic view of the laser beam focusing on an object surface as the machining head is moving; and 
         FIGS. 6A and 6B  are schematic views of the various operating positions according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The objectives above for the present invention, the features of structure, and function of the present invention are described according to preferred embodiments in accompanying figures. 
       FIG. 1  is a schematic view of the separate installations of the gantry-type machine and the laser path adjustment unit of the present invention. The laser apparatus, shown in  FIG. 1 , comprises a gantry-type machine  10  and a laser path adjustment unit  20 . The gantry-type machine  10  and the laser path adjustment unit  20  are independent units and can be installed separately. The gantry-type machine  10  is installed on the first bed  41 ; the laser path adjustment unit  20  and the laser source  21  thereof are installed on the second bed  42 . Therefore, when different workpiece materials and different machining conditions are required, different laser sources can be used. Then, the size of the second bed  42  can be changed to adapt for the volume of the laser source. Also, it is convenient to replace different laser sources  21 . However, the configuration is not limited to the previous one. When the working space is confined, the gantry-type machine  10  and the laser path adjustment unit  20  both can be installed on a single bed. Either of the first bed  41  and the second bed  42  can be a fixed or moveable bed or both can be fixed or moveable beds. 
     The above-mentioned gantry-type machine  10  has a first moving module  11  and a second moving module  12  movably connected to the first moving module  11 . The second moving module  12  has a moving reflector  14 . The third moving module  15  is movably connected to the second moving module  12  and is provided with a machining head  13 . In this configuration, the machining head  13  can move two-dimensionally (in the X-Y direction) or three-dimensionally (in the X-Y-Z direction). In another embodiment, the third moving module  15  can be omitted for simple machining or cost reduction. For example, the machining head  13  can be movably connected to the second moving module  12  through a slider such that the machining head  13  can move two-dimensionally (in the X-Y direction). 
     The above-mentioned first moving module  11 , for example, is an X-direction moving module. The second moving module  12  such as a Y-direction moving module is supported and connected to the first moving module  11  through two posts  1123 . The third moving module  15 , for example, is a Z-direction moving module. In the current embodiment, the first, the second, and the third moving modules  11 ,  12 ,  15 , are, for example, a linear guideway, a slider, and a driving motor, respectively. 
     In the current embodiment, the moving reflector  14  is disposed corresponding to the machining head  13  of the third moving module  15 . The machining head  13  is disposed at a height in the Z-direction above and is aligned with the workpiece  31 . In some embodiments, the height of the machining head  13  in the Z-direction is adjusted through the third moving module  15 . Besides, the machining head  13  has a beam input end  131  (like a reflecting mirror), at least one beam output end, and a switch device  134  (like a reflecting mirror). As shown in  FIG. 1 , the machining head  13  comprises a first beam output end  132  and a second beam output end  133 , but not limited to this. More beam output ends can be installed according to the machining requirements. In the current embodiment, the first beam output end  132  is formed by a focusing lens, for example. The second beam output end  133  is formed by a galvanometer, for example. Thus, the laser beam passing through the beam input end  131  is output from the first beam output end  132  or from the second beam output end  133 , controlled by the switch device  134 . 
     Moreover, the vision module  16  is movably connected to the second moving module  12  through a slider. The vision module  16  comprises a microscope and a light source to visibly display the surface of the workpiece  31 . 
     When the gantry-type machine  10  moves, two posts  123  of the second moving module  12  move in the X-direction on the first moving module  11 ; the third moving module  15  carries the machining head  13  and moves along the second movable module  12  and in the Y-direction. In addition, the height of the machining head  13  in the Z-direction is kept or adjusted through the third moving module  15 . In this way, the total moving distance of the machining head  133 , which is defined by the movement of the first moving module  11  and the second moving module  12  or defined by the first moving module  11 , the second moving module  12 , and the third moving module  15 . 
     The laser path adjustment unit  20  has a laser source  21 , a light path adjustment module  22 , and a source reflection assembly  23 . The laser source  21  is used to emit a laser beam. The source reflection assembly  23  comprises a first reflector  231 , a second reflector  232 , and a third reflector  233 . The light path adjustment module  22  has a guiding part  221  (e.g. a linear guideway or a slider) and a return reflection assembly  2221 ,  2222 . The return reflection assembly  2221 ,  2222  reciprocates on the guiding part  221  through the slider. 
     The above-mentioned first reflector  231  is disposed corresponding to the laser source  21  and the second reflector  232 ; the second reflector  232  and the third reflector  233  are disposed corresponding to the return reflection assembly  2221 ,  2222 ; the third reflector  233  is disposed corresponding to the moving reflector  14 . Consequently, the optical path length (OPL) of the laser beam travelling from the laser source  21  to the first beam output end  132  or to the second beam output end  133  is formed. 
     Therefore, the emitted laser beam travels from the first reflector  231  to the second reflector  232 , then from the second reflector  232  to the return reflection assembly  2221 ,  2222 , then from the return reflection assembly  2221 ,  2222  to the third reflector  233 . After that, the laser beam travels from the third reflector  233  to the moving reflector  14 , then from the moving reflector  14  to the beam input end  131  of the machining head  13 . Finally, the laser beam is selected to be output from the first beam output end  132  or from the second beam output end  133  of the machining head  13 . 
     Furthermore, the return reflection assembly  2221 ,  2222  move with the machining head  13  synchronously and reciprocates on the guiding part  221  over an adjustment distance to match the moving distance of the machining head  13  such that the traveling distance of the laser beam that travels from the laser source  21  to the first beam output end  132  or to the second beam output end  133  remains fixed, which further prevents an insufficient traveling distance of the laser beam because of the change of the light path caused by the movement of the machining head  13 . 
     It should be explained that the laser beam travels from the second reflector  232  to the return reflection assembly  2221 ,  2222  and then travels from the return reflection assembly  2221 ,  2222  to the third reflector  233 , which forms two parallel light paths. That is, the laser beam forms a dual light path in the light path adjustment module  22 . Therefore, the adjustment distance of the laser path adjustment unit  20  is half of the total moving distance of the machining head. For example, when the total moving distance of the machining head is L, the adjustment distance is ½ L. The total light path of the laser beam is the sum of the total moving distance of the machining head L and the adjustment distance ½ L. 
     Please continue to refer to  FIG. 2 . In the current embodiment, the moving reflector  14  and the third reflector  233  of the source reflection assembly  23  are parallel with the X-direction of the gantry-type machine  10  such that the laser beam can travel to the machining head  13  of the gantry-type machine  10  along a proper light path. The return reflectors  2221 ,  2222 , the first reflector  231 , the second reflector  232 , and the third reflector  233 , for example, can be reflecting mirrors, but not limited to this. In other embodiments, the laser path adjustment unit  20  can be disposed below or above the first bed  41  of the gantry-type machine  10 ; a light path of the laser beam can be formed by the configuration of the source reflection assembly  23  that is disposed corresponding to the laser source  21  and the moving reflector  14 , respectively. 
     Please continue to refer to  FIG. 3 . In an embodiment, the gantry-type machine  10  and the laser path adjustment unit  20  are connected to a control unit  30 . The control unit  30  controls the machining head  13  of the gantry-type machine  10  and the return reflection assembly  2221 ,  2222  of the laser path adjustment unit  20  to move synchronously and controls the laser source  21  to emit a laser beam. In more detail, the control unit  30  controls the total moving distance of the machining head  13  and the adjustment distance of the return reflection assembly  2221 ,  2222  according to the total moving distance of the machining head such that the gantry-type machine  10  and the laser path adjustment unit  20  move synchronously. 
     An example is given below to explain how the gantry-type machine  10  and the laser path adjustment unit  20  move synchronously. Also, several relative positions between the machining head  13  and the workpiece  31  are illustrated. For easy understanding, the following example shows the laser beam travels through the first beam output end  132  of the machining head  13 . Besides, the scales, the coordinates, and the relative positions shown in the following examples are not to limit the scope of the claims of the present invention. 
       FIGS. 4A-4E  are top views of the various operating positions of the present invention. As shown in these figures and  FIG. 1 , the workpiece  31  has a length of 200 mm and a width of 200 mm, for example. The linear movement range of the light path adjustment module  22  is 200 mm. When the machining head  13  is at the initial position, the upper left corner of the workpiece  31  on the coordinate of X=0, Y=0, Z=0 (i.e, the machining head  13  is kept at a height in the Z-direction, the same hereinafter), it means that the total moving distance of the machining head is 0. The return reflection assembly  2221 ,  2222  of the light path adjustment module  22  are at the rightmost of the guiding part  221 , which means the adjustment distance is 0 (refer to  FIG. 4A ). 
     Further, when the machining head  13  moves rightward and arrived at the upper right corner of the workpiece  31  on the coordinate of X=0, Y=200 mm, Z=0, it means that the total moving distance of the machining head is 200 mm; the adjustment distance is 100 mm leftwards. The return reflection assembly  2221 ,  2222  arrive at the center of the guiding part  221  (refer to  FIG. 4B ). 
     In addition, when the machining head  13  moves from the initial position (i.e., X=0, Y=0, Z=0) to the center of the workpiece  31  (i.e., X=100 mm, Y=100 mm, Z=0), it indicates that the total moving distance of the machining head is 200 mm; the adjustment distance is 100 mm leftwards. The return reflection assembly  2221 ,  2222  move from the rightmost of the guiding part  221  and arrive at the center of the guiding part  221  (refer to  FIG. 4C ). 
     Besides, when the machining head  13  moves from the initial position (i.e., X=0, Y=0, Z=0) to the lower left corner of the workpiece  31  (i.e., X=200 mm, Y=0, Z=0), it indicates that the total moving distance of the machining head is 200 mm; the adjustment distance is 100 mm leftwards. The return reflection assembly  2221 ,  2222  move from the rightmost of the guiding part  221  and arrive at the center of the guiding part  221  (refer to  FIG. 4D ). 
     Moreover, when the machining head  13  moves from the initial position (i.e., X=0, Y=0, Z=0) to the lower right corner of the workpiece  31  (i.e., X=200 mm, Y=200 mm, Z=0), it indicates that the total moving distance of the machining head is 400 mm; the adjustment distance is 200 mm leftwards. The return reflection assembly  2221 ,  2222  move from the rightmost of the guiding part  221  and arrive at the leftmost of the guiding part  221  (refer to  FIG. 4E ). 
       FIG. 5  is a schematic view of the laser beam focusing on an object surface as the machining head  13  is moving. The traveling distance of the laser beam emitted from the laser source  21  to the machining head  13  is maintained through the adjustment distance of the laser path adjustment unit  20  when the machining head  13  is moving. In this way, wherever the machining head  13  moves to the workpiece  31 , the laser beam outputted through the first beam output end  132  of the machining head  13  can focus on the surface of the workpiece  31  stably, which further obtains consistent cutting edges and facilitates the precision machining. 
     As shown in  FIGS. 6A and 6B , in another embodiment, a protrusion  311   a  protruding from the surface of the workpiece  31   a  forms a high surface and a low surface on the workpiece  31   a . For example, the high surface is roughly 20 mm higher than the low surface, but not limited to this. When moving to the upper right corner of the workpiece  31 , the machining head  13  meets the high surface, the machining head  13  will be adjusted and raised 20 mm in the Z-direction to the coordinate of X=0, Y=200 mm, Z=20 mm through the third moving module  15 . Thus, the total moving distance of the machining head is 220 mm. Meanwhile, the adjustment distance is 110 mm leftwards. The return reflection assembly  2221 ,  2222  move to the left of the center of the guiding part  221 . 
     The above description has detailed the present invention. However, the above-mentioned embodiments are only preferred ones and do not limit the scope of the present invention. The scope of the present invention should be embraced by the accompanying claims and includes all the equivalent modifications and not be limited to the previous description.