Abstract:
Fine abrasive machining of a part includes providing a tool having a plurality of successive portions configured and arranged so that each preceding portion provides a coarser abrasive machining while each subsequent portion provides a final abrasive machining, and providing a relative movement of the abrasive tool relative to the part so that first a portion of the tool configured a coarser abrasive machining machines a part and thereafter a portion of the tool configured for a finer machine provides abrasive machining of the part.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a method of and a device for fine abrasive machining of materials, and also to all abrasive tool provided therefor. 
         [0002]    Methods and devices for all abrasive machining, and abrasive tools for them are well known in the art. In known machining processes and equipment in order to provide a fine finished surface an abrasive machining is performed by multiple instruments and means, which carry out successive processes of removing the material from a workpiece in a way that a coarser machining is performed in preceding processes while a finer machining is performed in subsequent processes. For example, for fine abrasive machining of a glass surface, for example three spindles which carry abrasive grinding tools are first used; then, for example three further spindles with abrasive tools for prepolishinig machining are used; and then three tools with abrasive polishing slurry are utilized. Substantially similar processes, tools and equipment are used for fine abrasive machining of other materials. 
         [0003]    With the above described known abrasive machining, a significant number of tools with a complicated equipment and multi-step processes are utilized, which are characterized by increased cost of instruments and equipment, size of equipment, and time of machining. 
       SUMMARY OF THE INVENTION 
       [0004]    Accordingly, it is an object of the present invention to provide a method of and a device for fine abrasive machining of materials, and an abrasive tool provided therefor, which are further improvements of the existing methods, devices and tools. 
         [0005]    In keeping with these objects and with others it should become apparent hereinafter, one feature of the present invention resides, briefly stated, in a method of fine abrasive machining of a part, comprising the steps of providing a tool having a plurality of successive portions configured and arranged so that each preceding portion provides a coarser abrasive machining while each subsequent portion provides a finer abrasive machining; and providing a relative movement of the abrasive tool relative to the part so that first a portion of the tool configured for a coarser abrasive machining machines a part and thereafter a portion of the tool configured for a finer machining provides abrasive machining of the part. 
         [0006]    It is another object of the present invention to provide a device for abrasive machining of a part, comprising a tool having a plurality of successive portions configured and arranged so that each preceding portion provides a coarser abrasive machining while each subsequent portion provides a finer abrasive machining; and means providing a relative movement of the abrasive tool relative to the part so that first a portion of the tool configured for a coarser abrasive machining machines a part and thereafter a portion of the tool configured for a finer machining provides abrasive machining of the part. 
         [0007]    It is still a further object of the present invention to provide an abrasive tool for fine abrasive machining of a part, the tool having a plurality of successive portions configured and arranged so that each preceding portion provides a coarser abrasive machining while each subsequent portion provides a finer abrasive machining, so that with a relative movement of the abrasive tool relative to the part first a portion of the tool configured for a coarser abrasive machining machines a part and thereafter a portion of the tool configured for a finer machining provides abrasive machining of the part. 
         [0008]    When the method of abrasive machining is performed, the device for abrasive machining is designed, and an abrasive tool is configured in accordance with the present invention, instead of a multiple equipment a multiple step operation, a single abrasive tool can be used for abrasive machining starting from a coarse machining and proceeding until a final machining of the part. 
         [0009]    In accordance with another feature of the present invention, a working surface of the abrasive tool used in the inventive method and in the inventive device, can be inclined, and also a tool can be configured as a rotary tool with an axis of rotation which is inclined as well, so as to provide the above mentioned abrasive machining of parts. 
         [0010]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an end, axial view of an abrasive tool in accordance with the present invention, for use in an inventive method of fine abrasive machining and in an inventive device for fine abrasive machining; 
           [0012]      FIG. 2  is a side view showing an abrasive tool in accordance with the present invention; 
           [0013]      FIG. 3  is a side view of an inventive device for fine abrasive machining with the use of the inventive method and the inventive abrasive tool; and 
           [0014]      FIG. 4  is a perspective view showing another embodiment of an inventive abrasive tool, as well as an inventive method and an inventive device for fine abrasive machining. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]      FIG. 1  shows an abrasive tool in accordance with the present invention which is used for fine abrasive machining in a device for fine abrasive machining in accordance with the present invention. 
         [0016]    An abrasive tool in accordance with the present invention has a plurality of individual portions which are identified with reference numerals  1 ,  2 ,  3  and  4 . It is to be understood that it is possible to provide less than four portions or more than four portions, depending on a material of a part to be treated, a degree of fineness of abrasive machining, and many other factors. The tool is formed as an integral tool including all above portions formed integrally with one another. 
         [0017]    The portions  1 ,  2 ,  3 ,  4  of the tool shown in  FIG. 1  are configured for providing a different degree or fineness of abrasive machining. The preceding portions are provided for a coarser abrasive machining, while subsequent portions are provided for a finer abrasive machining. 
         [0018]    If the fine abrasive machining is performed with the abrasive tool shown in  FIG. 1 , so that the abrasive machining starts by the center of the tool and proceeds toward its periphery, then the portion  4  is configured for the coarsest abrasive machining, while the portion  1  is configured for the finest abrasive machining. 
         [0019]    For example for machining a glass parts, the portion  4  can contain abrasive particles such as diamond particles with a size of 150-200 micron and a concentration of 100%, the portion  2  can contain diamond particles with a size of 80-63 micron and concentration of 75%, the portion  2  can contain diamond particles with a size of 40-28 micron and a concentration of 50%, and the portion  1  can contain diamond particles with a size of 10-7 micron and a concentration of 25%. 
         [0020]    It is believed to be clear that the concentration is selected in accordance with the international standards, wherein 100% concentration means that there are 72 karat in one cubic inch of the portion. 
         [0021]    It is to be understood that both the size of the abrasive particles in the portions  1 ,  2 ,  3 ,  4  as well as the concentration of the abrasive particles in these portions can be different, depending on a material of a part to be treated, and other parameters of the method. 
         [0022]    If the fine abrasive machining is performed by starting from the periphery of the tool and progressing toward its center, the concentration of the abrasive particles decreases in the same direction. 
         [0023]    As shown in  FIG. 1 , the portions  1 ,  2 ,  3 ,  4  are formed as concentric portions arranged around a common center or axis A. 
         [0024]    With the inventive tool, in the inventive method and the inventive device, various materials can be subjected to abrasive machining, for example glass, ceramics, metals, ferrites, semiconductor crystals, etc. 
         [0025]    Various abrasives can be used as abrasive particles in the corresponding portions, such as diamonds, cubic boron nitride, aluminum oxide, cerium oxide, zirconium oxide, silicon carbide, etc. 
         [0026]    The machining of the materials can be performed for any areas of corresponding parts, such as surfaces, edges, bevels, arises, etc. 
         [0027]    In accordance with a further feature of the present invention, a working surface of the abrasive tool is inclined at a predetermined angle to a horizontal plane. 
         [0028]    As shown in  FIG. 3  the inclination of the working surface of the tool is performed with an angle α from the axis of the tool and going to its periphery, uniformly around the axis A. 
         [0029]    During abrasive machining of a part, for example a glass part shown in  FIG. 2 , the tool is arranged so that the axis of rotation A of the tool is inclined relative to a vertical axis by an angle β so that a part of the working surface of the tool at one side of the axis A is for example horizontal (at the right side of the axis A) and is in contact with the part to be machined, while another part of the tool is not in contact with the part to be abrasively machined (left side of the axis A. 
         [0030]    When as shown in  FIG. 2  the part to be machined, for example a glass part, is displaced relative to the tool or vice versa, the glass part is successively finely abrasively machined by the portions  4 ,  3 ,  2 ,  1  of the inventive tool, thus successively providing a coarser treatment, then a finer treatment, then a more finer treatment, and then a final fine treatment by the corresponding portions  4 ,  3 ,  2 ,  1 . 
         [0031]    In the embodiment shown in  FIGS. 1-3  the abrasive tool is formed as an abrasive disk with an end-side abrasive layer that include the above-mentioned portions. 
         [0032]      FIG. 4  shows another embodiment of the abrasive tool in accordance with the present invention, which is used in accordance with the present invention in the inventive device for fine abrasive machining. 
         [0033]    In the embodiment of  FIG. 4  a centreless fine abrasive machining is performed. For this purpose the abrasive tool is formed as a roller having a plurality of disk shaped portions  5 ,  6 ,  7 ,  8 ,  9  integrally attached to one another to form a single integral abrasive tool. A part to be machined is advanced between the abrasive tool and an opposite rotating roller so as to be successively finely machined. 
         [0034]    Each preceding disk-shaped abrasive portion of the tool shown in  FIG. 4  provides a coarser abrasive machining than each subsequent abrasive portion. The corresponding portions  5 ,  6 ,  7 ,  8 ,  9 , can have a size of abrasive particles 150-200 micron, 100-70 micron, 50-30 micron, 25-15 micron, 10-7 micron, with corresponding concentrations 100%, 80%, 60%, 40%, 20%. 
         [0035]    The device for fine abrasive machining shown in  FIG. 2  includes the abrasive tool described herein above, and means for rotating the abrasive tool around an axis A which are known per se in the art and formed for example as a rotatable spindle. 
         [0036]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of methods and constructions differing from the type described above. 
         [0037]    While the invention has been illustrated and described as embodied in a method of and a device for abrasive machining, and abrasive tool provided therefor, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
         [0038]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, be applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.