Patent Publication Number: US-2010108650-A1

Title: Automatic Positioning/Engraving Method For A Laser Engraving Machine

Description:
TECHNICAL FIELD 
     The present invention is related to a laser engraving method for a laser engraving machine and, more particular, to an automatic positioning/engraving method for a laser engraving machine, where at least two positioning points are positioned on the peripheries of a workpiece, a processor is then provided to calculate and decide a center between the two positioning points, and, finally, a driving unit is used to move a pen carriage to the center to start pattern engraving or cutting operation. 
     BACKGROUND 
     The process for laser engraving or cutting is very simple. Like printing a paper via a computer and a printer, patterns can be engraved onto a workpiece by using a laser engraving machine. The only difference is that printing is to apply ink onto a paper while laser engraving is to project laser onto a wooden article, an acryl, a plastic plate, a metallic plate or a stone and the engraving procedure can be easily completed. 
     It is a conventional way to position a workpiece on a working platform before a laser engraving process. Thereafter, the center of a pattern to be processed is obtained by means of measurement with a ruler. The pen carriage of a laser engraving system is then manually moved to the center of the workpiece. When the center of the pattern is also projected onto the workpiece, the position of the pattern to be engraved on the workpiece is determined. 
     Accordingly, a center is usually determined by means of measurement with a ruler on the workpiece or is roughly determined by visual estimation conventionally. By this way, deviation of the center resulted from such manual positioning is inevitable and it takes more time for manual positioning. In order to overcome these disadvantages, the present invention provides an automatic positioning/engraving method for a laser engraving machine after many years study, hard research, and developments. 
     SUMMARY OF THE DISCLOSURE 
     The primary object of the present invention is to provide an automatic positioning/engraving method for a laser engraving machine. The technical features of the present invention are: setting at least two positioning points on the peripheries of a workpiece; determining a center between the two positioning points by the calculation of a processor; automatically moving a pen carriage to the center to start pattern engraving or cutting. Thereby, when a pattern is accurately formed on a workpiece by using the method according to the present invention, it saves time without manual positioning and prevents errors resulted from manual positioning. 
     To achieve the above objectives, the present invention provides an automatic positioning/engraving method for a laser engraving or cutting machine comprising following steps: A. providing a workpiece; B. moving a pen carriage of the laser engraving machine to position at least two positioning points on the peripheries of the workpiece; C. providing a processor to calculate and decide a center between the two positioning points; and D. utilizing a driving unit to move the pen carriage to the center and begin pattern engraving or cutting. 
     In practice, in step B, a first positioning point and a second positioning point are preferably setup and a center between the first and second positioning points are calculated by utilizing the processor. 
     Alternatively, in step B, a first, a second, a third, and a fourth positioning point are preferably positioned. Based on the four coordinates, maximum and minimum values of the respective x-coordinate and y-coordinate values are obtained. Additionally, the mean values of the maximum and minimum values of the x-coordinate and y-coordinate are calculated. These mean values are further used as the coordinates of the center point. 
     The present invention will be apparent after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a flow chart of an automatic positioning/engraving method of the present invention. 
         FIG. 2  illustrates a schematic view showing step B and step C of the automatic positioning/engraving method in a first embodiment of the present invention; 
         FIG. 3  illustrates a schematic view showing a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1  that shows a flow chart of an automatic positioning/engraving method according to the present invention. The automatic positioning/engraving method comprises following steps: 
     A. providing a workpiece; 
     B. moving a pen carriage of the laser engraving machine to position at least two positioning points on the peripheries of the workpiece; 
     C. providing a processor to calculate and decide a center of the positioning points; and 
     D. utilizing a driving unit to move the pen carriage to the center and to begin the pattern engraving or cutting operation. 
       FIG. 2  shows a first preferred embodiment of the present invention. In this embodiment, a workpiece in rectangular shape is used as an example. According to the embodiment, a first positioning point and a second positioning point are positioned respectively. A center on the line aligning these two positioning points is then calculated by the processor. Preferably, the first and the second positioning points are two points on the peripheries of the workpiece having the longest distance than any other two points on the workpiece. 
     As shown in  FIG. 2 , a laser engraving machine  1  is provided on one lateral side thereon with a processor  12 , a screen  14 , and a keyboard  142 . Besides, the laser machine  1  is provided with a platform  16  on which a pen carriage  18  is provided capable of moving transversely and longitudinally. The pen carriage  18  has an infrared emitter/receiver  182  therein. A workpiece  2  is a plain plate and is positioned on the platform  16  of the laser engraving machine  1 . 
     In step B, the infrared emitter of the pen carriage  18  is used for positioning, the processor is used for reading the coordinate data fed back from a driving unit to decide the coordinates of the pen carriage  18 , and a display screen is used to show the coordinates. As shown in  FIG. 2 , when the pen carriage  18  is moved above the workpiece  2 , the infrared emitter of the pen carriage  18  emits infrared ray downwards. When the infrared receiver receives the reflected infrared ray, the information of the coordinates detected by the infrared ray is transmitted to the processor  12  and displayed on the screen  14  simultaneously. Accordingly, a first positioning point  30  is determined. In a similar way, a second positioning point  32  can be determined and displayed on the screen  14  when the pen carriage  18  is moved to the second positioning point  32 . 
     In step C, the processor  12  is used to figure out a center  50  on the line aligning the first and the second positioning points  30 ,  32  according to the coordinates of the first and the second positioning points  30 ,  32 . After obtaining the coordinates of the center  50 , the processor  12  activates a servo motor that can move the pen carriage  18  longitudinally or transversely to move the pen carriage  18  to the center  50  that is used as a reference point for starting pattern engraving or cutting operation. Besides, the servo motor used for moving the pen carriage  18  longitudinally or transversely is served as the driving unit (not shown in  FIG. 2 ). 
     In practice, the positioning method as described in step B, an infrared emitter can be utilized to emit infrared ray. When the emitter irradiates on the platform  16  and a storage key on the keyboard  142  is pressed, the processor  12  reads the data fed back from the driving unit to determine the coordinates of the pen carriage  18  and display the coordinates on the screen  14 . By the method set forth above, the coordinates of the first and the second positioning points  30 ,  32  can be accurately obtained. After the calculation executed by the processor  12 , the pen carriage  18  can be moved to the center  50  under the control of the driving unit to start pattern engraving or cutting operation. 
       FIG. 3  shows a second preferred embodiment of the present invention. For better description, all features similar to those of the first preferred embodiment are omitted. In the second preferred embodiment, the workpiece  2 ″ is a rectangular, however, applicable to any irregular shape workpiece. In practice, a center  52  is determined after four positioning points, a first, a second, a third, and a fourth positioning point  40 ,  42 ,  44 ,  46 , are positioned. 
     As shown in  FIG. 3 , when the four positioning points  40 ,  42 ,  44 ,  46  are determined, the maximum and minimum values of the x-coordinate and y-coordinate values are respectively determined based on the coordinates of the four positioning points  40 ,  42 ,  44 ,  46 . Then, the mean values of the maximum and minimum values of the x-coordinate and y-coordinate values are calculated by the processor  12 . The mean values serve as the center  52  of the four positioning points  40 ,  42 ,  44 ,  46 . Finally, the pen carriage  18  is moved to the center  52  to start pattern engraving or cutting operation by the driving unit. 
     In conclusion, according to the above description, the present invention surely can accomplish the expected objects to provide an automatic positioning/engraving or cutting method for a laser carving machine. Adopting this method can save time for manual positioning, avoid errors resulted from any manual positioning, decide accurately the position for processing a pattern, and save material cost as well. It is new and can be put into industrial use. 
     Although the embodiments of the present invention have been described in details, various modifications and variations may be made by those skilled in the art from the teachings disclosed hereinabove. Therefore, it should be understood that any modification and variation equivalent to the spirit of the present invention be regarded to fall into the scope defined by the appended claims.