Abstract:
A laser machining device with a proximity-warning function in relation to a workpiece being machined includes a laser element and a position feedback unit. The laser element includes a laser head for emitting a focused laser beam and a movable member for moving the laser head. The position feedback unit is positioned on the movable member and connected to an alerting circuit. When an elastic contacting member in the position feedback unit is compressed because the distance between the laser head and the workpiece is less than a minimum permitted distance the alerting circuit issues an alert.

Description:
FIELD 
       [0001]    The present invention relates to machining devices, and particularly to a laser machining device. 
       BACKGROUND 
       [0002]    In laser machining, such as laser cutting engraving, a laser beam emitted from a laser head should be focused on a surface of a workpiece to be machined. Because different workpieces have different thicknesses, a height of the laser head relative to the workpieces requires to be adjusted and this can be problematic. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    The components of the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments of the present disclosure. 
           [0004]      FIG. 1  is a schematic view of a laser machining device, according to an exemplary embodiment of the present disclosure, the laser machining device including a position feedback unit. 
           [0005]      FIG. 2  is a schematic view of the position feedback unit of the laser machining device of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” The references “a plurality of” and “a number of” mean “at least two.” 
         [0007]      FIGS. 1 and 2  show one embodiment of a laser machining device  100 . The laser machining device  100  is configured for machining a workpiece  200 . The laser machining device  100  includes a supporting base  10 , a laser element  20 , and a position feedback unit  30  fixedly connected to the laser element  20 . 
         [0008]    The supporting base  10  includes a working surface  11 , the workpiece  200  being fixedly positioned on a predetermined position of the working surface  11 . Different workpieces  200  may have different thicknesses. 
         [0009]    The laser element  20  is positioned above the working surface  11  of the workpiece  200 , the laser element  20  is movable along a first direction substantially parallel to the working surface  11  and a second direction substantially perpendicular to the working surface  11 . The laser element  20  includes a movable member  21  and a laser head  22  fixed on the movable member  21 . The movable member  21  drives the laser head  22  to move along the first direction and the second direction. In detail, the movable member  21  is a three-dimensional robot arm. The laser head  22  emits a focused laser beam. A distance from a distal end of the laser head  22  facing toward the supporting base  10  to a focal point of the laser head  22  is D, and the distance D equals a distance between the laser head  22  and the workpiece  200  in a laser machining process. 
         [0010]    The position feedback unit  30  is fixed on the movable member  21  and is fixed relative to the laser head  22 . The position feedback unit  30  includes an elastic contacting member  31  and an alerting circuit  32 . The elastic contacting member  31  includes an upper portion  311  fixed on the movable member  21 , a lower portion  312  connected to the upper portion  311 , and an elastic portion  313  positioned between the upper portion  311  and the lower portion  312 . The upper potion  311  includes a first base  3111  and a barrel  3112  connected to the first base  3111 . The lower portion  312  includes a second base  3121 , a guiding bar  3122  formed on a surface of the second base  3121  facing toward the first base  3111 , and a contacting protrusion  3123  formed on another surface of the second base  3121  facing toward the supporting base  10 . The guiding bar  3122  is slidably inserted into the barrel  3112 , a restricting structure (not shown) may be formed between the barrel  3112  and the guiding bar  3122  to prevent the guiding bar  3122  falling out of the barrel  3112 . An end surface of the contacting protrusion  3123  is substantially a spherical surface. The elastic portion  313  is elastically sandwiched between the first base  3111  and the second base  3121 . In this embodiment, the elastic portion  313  is a helical spring, the elastic portion  313  sleeves on the barrel  3112  and the guiding bar  3122 , and the elastic portion  313  is between and abuts the first base  3111  and the second base  3121 . 
         [0011]    In use, when the elastic contacting member  31  is under maximum compression, a distance between the distal end of the contacting protrusion  3123  and the movable member  21  is larger than a distance between the distal end of the laser head  22  and the contacting protrusion  3123 . When the elastic contacting member  31  is uncompressed, a distance between the distal end of the contacting protrusion  3123  and the movable member  21  is less than a distance between the focal point of the laser head  22  and the movable member  21 . 
         [0012]    The alerting circuit  32  is activated when a distance between the laser head  22  and the workpiece  200  is less than a permitted value, the permitted value is to prevent the laser head  22  from hitting the workpiece  200 . The alerting circuit  32  includes a power source  321 , an alerting device  322 , a first electrode  323 , and a second electrode  324  opposite to the first electrode  323  and spaced from first electrode  323  for a predetermined distance. The first electrode  323  is electrically connected to a positive end of the power source  321  and fixed on the first base  3111 , and the second electrode  324  is electrically connected to a negative end of the power source  321  and is fixed on the second base  3121 . In this embodiment, the first electrode  323  is a conductive piece  323 , the second electrode  323  includes a bottom base  3241 , a supporting post  3242  fixed on the bottom base  3241  and protruding toward the first electrode  323 , and an electrode piece  3243  fixed on an distal end of the supporting post  3242 . The supporting post  3242  is made from an elastic material, and the supporting post  3242  is electrically connected to the negative end of the power source  321  by a wire (not shown) passing through the bottom base  3241  and the supporting post  3242 . In another embodiment, the structure of the first electrode  323  is similar to that of the second electrode  324 , the first electrode  323  and the second electrode  324  are interchangable. The alerting device  323  emits a signal when the first electrode  323  and the second electrode  324  contact each other. The alerting signal can be an audible signal, a visual signal, or other type of signal. Specifically, the alerting device  322  can be a beeper or a light-emitting diode (LED). 
         [0013]    A distance between the first electrode  323  and the second electrode  324  can be set according to different requirements. In this embodiment, a minimum permitted distance between the distal end of the laser head  22  and the workpiece  200  is preset, and the minimum permitted distance keeps the laser head  22  from hitting the workpiece  200  in a process of adjustment. When the first electrode  323  and the second electrode  324  contact each other, a distance between the laser head  11  and the workpiece  200  is equal to the minimum permitted distance. The minimum permitted distance is less than the distance D. 
         [0014]    In use, the workpiece  200  is positioned at a predetermined position of the working surface  11 , a machining position of the laser element  20  is adjusted according to a particular thickness of the workpiece  200 , and then a laser machining process is started. In the adjusting process, if a distance between the distal end of the laser head  22  and the workpiece  200  is less than the minimum permitted distance, the elastic contacting member  31  contacts the workpiece  200 , the workpiece  200  presses the second base  3121  to move toward the first base  3111 , the second electrode  324  contacts the first electrode  323  during the movement of the second base  3121 , causing the alerting device  322  send a warning to an operator. Therefore, collisions between the laser element  20  and the workpiece  200  during the adjusting process are avoided, preventing damage to the laser element  20  and the workpiece  200 . 
         [0015]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being exemplary embodiments of the disclosure.