Abstract:
A sandblasting apparatus for cutting a plate-shaped workpiece into a plurality of separate tablets includes a chamber defining a cavity, a support assembly received in the cavity, a sandblasting assembly for spraying sand toward the workpiece, a first mask located between the sandblasting assembly and the support assembly, a second mask located between the sandblasting assembly and the support assembly, and a mask switching member for selectively placing the first mask or the second mask over the workpiece. The support assembly is configured for supporting the workpiece and the tablets. The first mask cooperates with the sandblasting assembly to remove unwanted portions of the workpiece thus obtaining a tablet network consisting of a plurality of tablets and a plurality of connecting portions interconnected between the tablets. The second mask cooperates with the sandblasting assembly to remove the connecting portions of the tablet network thus obtaining a plurality of separated tablets.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to cylindrical grinding technology and, particularly, to a sandblasting apparatus. 
     2. Description of Related Art 
     Many kinds of workpieces need to be ground to a desired shape before use. For example, optical lenses used in a digital camera are ground to a desired shape and size to allow their installation into lens barrels. Generally, in a cylindrical grinding process, a number of original lenses having a rectangular shape are bonded together by ultraviolet glue to form a cube, the cube is fixed on a fixing device and the original lenses ground to form a number of optical lenses, the glue is removed to separate the optical lenses, and the optical lenses are cleaned. However, the separation and cleaning are time-consuming and costly. Further, it is difficult to ensure the glue is completely removed, which can decrease the optical performance of the optical lenses. 
     Therefore, it is desirable to provide a sandblasting apparatus which can overcome or at least alleviate the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, isometric view of a sandblasting apparatus including a door according to a first exemplary embodiment, showing the door closed. 
         FIG. 2  is similar to  FIG. 1 , but showing the door open. 
         FIG. 3  is a planar view of the sandblasting apparatus of  FIG. 1 , with the door removed. 
         FIG. 4  is a schematic, isometric view of a first mask of the sandblasting apparatus of  FIG. 3 . 
         FIG. 5  is a schematic, isometric view of a second mask of the sandblasting apparatus of  FIG. 3 . 
         FIG. 6  is a schematic, isometric view of a plate-shaped workpiece. 
         FIG. 7  is a schematic, isometric view of a tablet network, after the plate-shaped workpiece being cut by a sandblasting assembly of  FIG. 3 . 
         FIG. 8  is a planar view of a sandblasting apparatus, according to a second exemplary embodiment. 
         FIG. 9  is a schematic, isometric view of a sandblasting apparatus, according to a third exemplary embodiment. 
         FIG. 10  is a cutaway view of the sandblasting apparatus of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-3 , a sandblasting apparatus  10 , according to a first exemplary embodiment, is configured for cutting a plate-shaped workpiece  20  (shown in  FIG. 6 ) into a tablet network  20   a , (shown in  FIG. 7 ) and cutting the tablet network  20   a , into a number of tablets  20   b , (shown in  FIG. 7 ). 
     The sandblasting apparatus  10  includes a chamber  12 , a sandblasting assembly  14 , a support assembly  15 , a mask switching member  16 , a first mask  17 , a second mask  18 , and a conveyor assembly  19 . 
     The chamber  12  is substantially a cube and defines a cavity  12   a . The chamber  12  includes an upper wall  120 , a lower wall  121 , a left sidewall  122 , a right sidewall  123 , a front sidewall  124 , a back sidewall  125 , and a partition plate  126 . The upper wall  120  is substantially parallel to the lower wall  121 . The left sidewall  122  is substantially parallel to the right sidewall  123 . The front sidewall  124  is substantially parallel to the back sidewall  125 . The left sidewall  122 , the front sidewall  124 , the right sidewall  123 , and the back sidewall  125  are connected end-to-end to each other. The left sidewall  122 , the front sidewall  124 , the right sidewall  123 , and the back sidewall  125  connect the upper wall  120  to the lower wall  121 . The upper wall  120  defines a first through hole  127  and a second through hole  128  apart from the first through hole  127 . A door  13  is attached to the front sidewall  124  and is configured for closing or opening the cavity  12   a . The partition plate  126  extends from the lower wall  121  and divides the cavity  12   a  into a preparation cavity  12   b  and a spraying cavity  12   c . The partition plate  126  is apart from the upper wall  120  to make the preparation cavity  12   b  communicate with the spraying cavity  12   c . The lower wall  121  defines a number of vent ports  129  in the spraying cavity  12   c . The diameter of the vent port  129  is larger than those of the tablets  20   b  and the size of the cutting scrap, and is less than those of sand sprayed by the sandblasting assembly  14 . That is, the sand can pass through the vent port  129 , while the tablets  20   b  and the cutting scrap cannot pass through the vent port  129 . 
     The sandblasting assembly  14  is positioned on the upper wall  120 . The sandblasting assembly  14  extends through the first through hole  127  and enters the spraying cavity  12   c . A portion of the sandblasting assembly  14  outside the chamber  12  is connected to a sand supplying unit (not shown). A portion of the sandblasting assembly  14  inside the chamber  12  is opposite to the support assembly  15 . 
     The support assembly  15  includes two support arms  152  and two first rollers  154 . The two support arms  152  are apart from each other. One end of each support arm  152  is fixed to the back sidewall  125 , and the other end of each support arm  152  is a free end. Each arm  152  defines a first fixing hole  156 . The first rollers  154  are fixed in the first fixing holes  156  and are driven to rotate by a driving member (not shown). The support assembly  15  is configured for supporting the plate-shaped workpiece  20  and the tablet network  20   a  and aligning the plate-shaped workpiece  20  and the tablet network  20   a  with the sandblasting assembly  14 . 
     The mask switching member  16  includes a stator  162 , a rotor  164 , and a support rod  166 . The stator  162  is fixed to the upper wall  120  and is apart from the sandblasting assembly  14 . The rotor  164  extends from the stator  162  and passes through the second through hole  128  to enter the cavity  12   a . The support rod  166  is fixed to a distal end of the rotor  164  and includes a first end  1662  and a second end  1664  opposite to the first end  1662 . The first end  1662  and the second end  1664  are at opposite sides of the rotor  164 . 
     Referring to  FIG. 4 , the first mask  17  includes a first frame  172 , a first shielding portion array including a number of first shielding portions  174 , and a number of first connection portions  176 . The first frame  172  is substantially rectangular. The first frame  172  is fixed to the first end  1662  and is parallel to the lower wall  121 . The first shielding portion array is positioned in the first frame  172 . In this embodiment, the first shielding portion array is a rectangular array. Each first shielding portion  174  has a shape conforming to the corresponding tablet  20   b . The first connection portions  176  are positioned in the first frame  172 . The first connection portions  176  are interconnected between the first shielding portions  174  and connect the first shielding portions  174  to the first frame  172  in a first fashion. In this embodiment, four first connection portions  176  are equidistantly arranged around the first shielding portion  174 . Four first joints between the first connection portions  176  and each first shielding portion  174  are homogeneous distributed. 
     Referring to  FIG. 5 , the second mask  18  includes a second frame  182 , a second shielding portion array including a number of second shielding portions  184 , and a number of second connection portions  186 . The second frame  182  is substantially rectangular. The second frame  182  is fixed to the second end  1664  and is parallel to the lower wall  121 . The second shielding portion array is positioned in the second frame  182 . In this embodiment, the second shielding portions  184  have a same pattern as that of the first shielding portions  174 . That is, the second shielding portion array is the same as the first shielding portion array. The shape of the second shielding portions  184  are the same as those of the first shielding portions  174 . The second connection portions  186  are positioned in the second frame  182 . The second connection portions  186  are interconnected between the second shielding portions  184  and connect the second shielding portions  184  to the second frame  182  in a second fashion different from the first fashion. The second connection portions  186  are distinctly oriented from the first connection portions  176 . In this embodiment, two second connection portions  186  are equidistantly arranged around each second shielding portion  184 . Two second joints between the second connection portions  186  and each second shielding portion  184  are homogeneous distributed. The positions of the first joints are different from that of the second joints. In other words, if the first shielding portions  174  are overlapped by the second shielding portions  184 , the second connection portions  186  underlaps from the first connection portions  176 . 
     In other embodiments, the first frame  172  and the second frame  182  may be round, and the first shielding portion array and the second shielding portion array may be a circular array. 
     Referring to  FIG. 2 , the conveyor assembly  19  is positioned in the preparation cavity  12   a . The conveyor assembly  19  is higher than the partition plate  126  and coplanar with the support assembly  15 . The conveyor assembly  19  includes a support plate  192  and two second rollers  194 . One end of the support plate  192  is fixed to the back sidewall  125 , and the other end of the support plate  192  is a free end. Two second fixing holes  196  are defined in the support plate  192  and are apart from each other. The second rollers  194  are fixed in the second fixing holes  196  and are driven to rotate by a driving member (not shown). The conveyor assembly  19  is configured for conveying the plate-shaped workpiece  20  to the support assembly  15 . 
     In other embodiments, the structure of the conveyor assembly  19  may be the same as that of the support assembly  15 . 
     Referring to  FIGS. 2-7 , a method for machining a plate-shaped workpiece  20 , using the sandblasting apparatus  10 , includes the following steps. 
     First, the door  13  is opened and the plate-shaped workpiece  20  is supported on the conveyor assembly  19 . 
     Second, the door  13  is closed, the plate-shaped workpiece  20  is conveyed to the support assembly  15 , and the plate-shaped workpiece  20  is aligned with the sandblasting assembly  14 . In detail, the second rollers  194  are driven to roll by the driving member (not shown) so that the plate-shaped workpiece  20  moves toward the support assembly  15 . The first rollers  154  are driven to roll by the driving member (not shown) so that the plate-shaped workpiece  20  is aligned with the sandblasting assembly  14 . 
     Third, the plate-shaped workpiece  20  is covered by the first mask  17  and exposed by the second mask  18 . In detail, the first mask  17  and the second mask  18  rotate with rotation of the stator  164 . The first mask  17  covers the plate-shaped workpiece  20 , while the second mask  18  exposes the plate-shaped workpiece  20 . 
     Fourth, the plate-shaped workpiece  20  is cut into a tablet network  20   a by spraying sand toward the plate-shaped workpiece  20  covered by the first mask  17 . 
     Fifth, the tablet network  20   a , is covered by the second mask  18  and is exposed by the first mask  17 . In detail, the first mask  17  and the second mask  18  rotate with rotation of the stator  164 . The second mask  18  covers the tablet network  20   a , while the first mask  18  exposes the tablet network  20   a.    
     Sixth, the tablet network  20   a  is cut into a number of tablets  20   b  by spraying sand toward the tablet network  20   a  covered by the second mask  18 . During this step, the tablets  20   b  fall on the lower wall  121  in the spraying cavity  12   c.    
     Seventh, sand stacked on the lower wall  121  in the spraying cavity  12   c  is evacuated from the chamber  12  through the vent ports  129 . 
     Eighth, the door  13  is opened and the tablets  20   b  are removed from the cavity  12   a.    
     During machining, no glue is needed, thus eliminating the need for the separation and glue cleaning. This saves time and money, and ensures a quality product. Further, the sand sprayed by the sandblasting assembly  14  and cutting scrap of the plate-shaped workpieces  20  are blocked by the door  13 , which protects the operator. 
     Referring to  FIG. 8 , a sandblasting apparatus  30 , according to a second exemplary embodiment, is shown. The differences between the sandblasting apparatus  30  of this embodiment and the sandblasting apparatus  10  of the first embodiment are: a chamber  32  of the sandblasting apparatus  30  omits the partition plate, and the sandblasting apparatus  30  omits the conveyor assembly, and a support assembly  35  of the sandblasting apparatus  30  includes only two support arms  352  for supporting the plate-shaped workpiece  20 . 
     During machining using the sandblasting apparatus  30 , the plate-shaped workpiece  20  is directly supported by the support assembly  35 . That is, the conveying step is omitted. 
     Referring to  FIG. 9-10 , a sandblasting assembly  40 , according to a third exemplary embodiment, is shown. The differences between the sandblasting assembly  40  of this embodiment and the sandblasting apparatus  10  of the first embodiment are: one end of each of support arms  452  of the sandblasting assembly  40  is fixed to the back sidewall  425  and the other end of each of the support arms  452  is fixed to the front sidewall  424 , one end of a support plate  492  of the sandblasting assembly  40  is fixed to the back sidewall  425 , and the other end of the support plate  492  is fixed to the front sidewall  424 , the sandblasting assembly  40  omits a door on a front wall  424 , and two doors  50  are attached to a left sidewall  422  and a right sidewall  423 , respectively. 
     During a machining process using the sand-blasting apparatus  40 , the plate-shaped workpiece  20  is supported on the conveyor assembly  49  through the door  50  attached on the right sidewall  423 . After the tablets  20   b  are formed, the tablets  20   b  are removed from the chamber through the door  50  attached on the left sidewall  422 . 
     The advantages of the sandblasting apparatus  40  of the third exemplary embodiment are similar to those of the sandblasting apparatus  10  of the first exemplary embodiment. Further, the conveying step is steadier as two ends of the support plate  492  are fixed and two ends of the support arms  452  are fixed. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments. The disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.