Abstract:
A grinding apparatus for grinding at least one workpiece includes a base, a first pressing portion, and a second pressing portion. The base is configured for receiving the workpiece. The first pressing portion and a second pressing portion are configured for applying a pressing force against the workpiece cooperatively, so as to hold the workpiece between the first pressing portion and the second pressing portion. The first pressing portion and the second pressing portion are moveable and rotatable relative to the base for removing the workpiece apart from the base and rotating the workpiece clockwise and counter-clockwise. A grinding method is also provided.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to a grinding apparatus having a pressing portion for shaping a surface of a workpiece. 
         [0003]    2. Description of Related Art 
         [0004]    A roll grinder is generally utilized to round and/or polish a surface of a workpiece (see “High Efficiency Deep Grinding of a Low Alloy Steel with Plated CBN Wheels”, CIRP Annals-Manufacturing Technology, pp. 241-244, Volume 51, Issue 1, 2002). A typical roll grinder includes a pair of hollows. In a grinding process, the hollows are pumped/evacuated so as to create suction to hold a workpiece. The workpiece is then grinded using a grinding wheel. However, this grinder is not very efficient because the grinder can only shape one workpiece at a time. 
         [0005]    There are grinding methods for grinding a number of workpieces at one time. In one related grinding method, the workpieces are placed on a grinding bed, coated with a ultraviolet (UV) emulsion, and exposed to a UV light to cure the UV emulsion until the workpieces become attached to the grinding bed. The workpieces are grinded, and the UV emulsion is melted to displace/detach the workpieces from the grinding bed. However, drawbacks to this grinding method include contamination from retention of the UV emulsion on the workpieces and the steps of curing and melting the UV emulsion are time consuming and increase production costs. 
         [0006]    Therefore, a grinding apparatus and a grinding method that avoids potential shortcomings associated with the UV emulsion and that is generally quicker and cheaper than the known mounting methods associated with roller grinders is desired. 
       SUMMARY 
       [0007]    A grinding apparatus for grinding at least one workpiece includes a base, a first pressing portion and a second pressing portion. The base is configured for receiving the workpiece. The first pressing portion and a second pressing portion are configured for pressing against the workpiece cooperatively, so as to hold the workpiece between the first pressing portion and the second pressing portion. The first pressing portion and the second pressing portion are moveable and rotatable relative to the base for removing the workpiece from the base and rotating the workpiece clockwise and counter-clockwise. 
         [0008]    Other advantages and novel features of the present grinding apparatus and grinding method will become more apparent from the following detailed description of preferred embodiments, when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Many aspects of the present apparatus and method can be better understood with reference to the following drawings. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0010]      FIG. 1  is a schematic, isometric view of an embodiment of a grinding apparatus. 
           [0011]      FIG. 2  is a flow chart of an embodiment of a grinding method using the grinding apparatus of  FIG. 1 . 
           [0012]      FIG. 3  is an isometric view of early stages of the process of the grinding method of  FIG. 2  using the grinding apparatus of  FIG. 1 . 
           [0013]      FIG. 4  is an isometric view of middle stages of the process of the grinding method of  FIG. 2  using the grinding apparatus of  FIG. 1 . 
           [0014]      FIG. 5  is an isometric view of latter stages of the process of the grinding method of  FIG. 2  using the grinding apparatus of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0015]    Embodiments of the present apparatus and method will now be described in detail below and with reference to the drawings. 
         [0016]    Referring to  FIG. 1 , a grinding apparatus  100  includes a holding device  12 , a base  14  and two blocking members  16 . The base  14  is configured for receiving the workpieces  30 . In the illustrated embodiment, the grinding apparatus  100  is configured for grinding a plurality of workpieces  30  to a cylindrical shape or polish a surface of the workpiece  30 . 
         [0017]    The holding device  12  includes a first pressing portion  122  and a second pressing portion  124 . The first pressing portion  122  includes a first driving member  126 , a first rotation rod  128  and a first contact element  130 . The holding device  12  is configured to hold the workpieces  30  between the first pressing portion  122  and the second pressing portion  124  by pressing against the workpieces  30 . 
         [0018]    The first driving member  126  is connected to a distal end of the first rotation rod  128 . The first driving member  126  is configured for driving the first rotation rod  128  to rotate about a principal axis of the first rotation rod  128 . The first contact element  130  is attached to a proximal end of the first rotation rod  128 . The first contact element  130  is configured for contacting and holding the workpieces  30 . 
         [0019]    The second pressing portion  124  includes a second driving member  132 , a second rotation rod  134  and a second contact element  136 . The second driving member  132  is connected to a proximal end of the second rotation rod  134 . The second driving member  132  is configured for driving the second rotation rod  134  to rotate about a principal axis of the second rotation rod  134 . The second contact element  136  is attached to a distal end of the second rotation rod  134 . The first rotation rod  128  is substantially coaxial to the second rotation rod  134 . The second contact element  136  is configured for contacting and holding the workpieces  30 . In one embodiment, the first contact element  130  and the second contact element  136  are made of a flexible material, such as rubber or flexible epoxy resin, to prevent scraping the workpieces  30 . 
         [0020]    The first contact element  130  is set facing towards the second contact element  136  for holding the workpieces  30 . The first pressing portion  122  and the second pressing portion  124  can be moved towards or away from each other to allow holding the workpieces  30  with different thicknesses. 
         [0021]    The base  14  includes a groove  144  configured for receiving the workpieces  30 . The workpieces  30  to be grinded could be, for example, a plurality of square wafers, a plurality of square lenses, or other optoelectronic elements. Therefore, a shape of the groove  144  corresponds to a shape of the workpieces  30  or a shape that reduces the potential degrees of freedom of the workpiece. For example, the groove  144  may be V-shaped for holding the workpiece having at least one corner corresponding to that V-shape. In the illustrated embodiment, the groove  144  is defined by two inclined surfaces  146  forming an angle between the two inclined surfaces  146  that approximately equals 90 degrees. In this embodiment, the workpieces  30  to be grinded are all square shaped and have the same size. It may be appreciated that workpieces with different shapes can also be grinded by the grinding apparatus  100 . 
         [0022]    Two blocking members  16  are configured for blocking the workpieces  30  and squeezing the workpieces  30  to closely contact with one another in the groove  144 . In one embodiment, the blocking member  16  is made of a high density material such as metal or an alloy. A material of the blocking member  16  can be selected from a group consisting of iron, copper, and stainless steel. In the illustrated embodiment, the blocking member  16  is cylindrical shaped. A radius of the blocking member  16  should be equal to a radius of the workpieces  30  after grinding. The blocking member  16  confirms whether the size of the workpieces  30  is large enough to form a cylindrical shape with a predetermined radius by comparing the surface of the blocking member  16  with that of the workpieces  30 . For example, if the blocking member  16  is larger than the workpieces  30 , then the workpieces  30  should not be grinded and replaced with workpieces  30  that are larger than the blocking member  16 . 
         [0023]      FIG. 2  is a flowchart illustrating an embodiment of a grinding method  400  using the grinding apparatus  100 . Depending on the embodiment, certain of the blocks described below may be removed, others may be added, and the sequence of blocks may be altered. The grinding method includes the following blocks:
   Block  402 : providing a base  14  having a groove  144 , placing a plurality of workpieces  30  into the groove  144  of the base  14 ;   Block  404 : the plurality of workpieces  30  contacting with one another;   Block  406 : providing a holding device  12  comprising a first rotatable pressing portion  122  and a second rotatable pressing portion  124 , the first pressing portion  122  and the second pressing portion  124  being configured for holding the plurality of workpieces  30 ;   Block  408 : removing the base  14  and driving the first pressing portion  122  and the second pressing portion  124  to rotate clockwise or counter-clockwise;   Block  410 : grinding the workpieces  30  held between the first pressing portion  122  and the second pressing portion  124 , obtaining a finished product.     
         [0029]    Referring to  FIG. 3 , in block  402 , the plurality of workpieces  30  is placed in the groove  144  of the base  14 . The workpieces  30  are in contact with the two inclined surfaces  146 . In block  404 , the two blocking elements  16  are received in the groove  144  and the workpieces  30  are sandwiched between the two blocking elements  16 . The two blocking elements  16  are moved toward the workpieces  30  to make the workpieces  30  closely contact with one another. 
         [0030]    Referring to  FIG. 4 , in block  406 , the first pressing portion  122  and the second pressing portion  124  sandwich the two blocking members  16 . The first rotation rod  128  and the second rotation rod  134  should both be coaxial to the workpieces  30 . Then, the two blocking members  16  are removed and the first pressing portion  122  and the second pressing portion  124  are moved towards the workpieces  30  to sandwich the workpieces  30  together. The first contact element  130  and the second contact element  136  each contacts one of the plurality of workpieces  30 . The compression force applied to the workpieces  30  by the first pressing portion  122  and the second pressing portion  124  should be strong enough to hold the workpieces  30  between the first contact element  130  and the second contact element  136 . 
         [0031]    Referring to  FIG. 5 , in block  408  and  410 , the base  14  is removed. A grinding wheel  18  is provided to grind the workpieces  30 . The grinding wheel  18  is driven by a motor (not shown) and to grind the workpieces  30 . A principal axis of the grinding wheel  18  is parallel with that of the workpieces  30  while the grinding wheel  18  is grinding the workpieces  30 . 
         [0032]    While the grinding wheel  18  rotates to grinding the workpieces  30 , the workpieces  30  are driven to rotate about a principal axis of the first rotation rod  128  and the second rotation rod  134 . The first and second rotation rods  128  and  134  are rotated by the first and second driving members  126  and  132 , respectively. A rotation speed and a rotation direction of the first rotation rod  128  must be equal to a rotation speed and a rotation direction of the second rotation rod  134 . After the grinding process is completed, a plurality of finished products (not shown) is obtained. In the illustrated embodiment, the finished products are rounded products such as rounded lenses. 
         [0033]    It is to be understood that the above-described embodiment is intended to illustrate rather than limit the invention. Variations may be made to the embodiment without departing from the spirit of the invention as claimed. The above-described embodiments are intended to illustrate the scope of the invention and not restrict the scope of the invention.