Abstract:
The present invention relates to an insert for slot milling, and more specifically, to an insert for slot milling which can smoothly form a front end surface of a concave portion of a slot formed at a cutting target, and provides a safe use thereof by preventing the erroneous installation of cutting inserts coupled with insert-installation seats on both sides of a milling cutter body to prevent damage of the cutting inserts and the milling cutter. To this end, the present invention is characterized in that the plurality of cutting inserts are provided around the slot milling cutter body, one of two cutting inserts protrudes with respect to one side of the milling cutter body and the other protrudes with respect to the opposite side of the milling cutter body, and two cutting inserts are formed with different structures to prevent the erroneous installation thereof on the insert-installation seats prepared on both sides of the milling cutter body.

Description:
TECHNICAL FIELD 
     The present invention relates to an insert for slot milling, and more particularly, to an insert for slot milling that can smoothly form a shape of a concave portion of a slot formed in a work material and that can enable safe use of a milling cutter by preventing erroneous coupling of left and right side surfaces of a cutting insert coupled to left and right seats of the slot milling cutter. 
     BACKGROUND ART 
     In a cutting processing using a rotation slot milling cutter, a processing of a slot shape is in a trend of gradually increasing, unlike existing slitting use, and when processing such a slot, a processing request quality after a slot processing gradually increases, and as a request of a radius form in a slot corner portion together increases, necessity of improvement of a structure of a cutting insert and a milling cutter appropriate thereto increases. 
     For reference, the slot milling is to process a concave portion of a concave form. 
       FIG. 1A  is a perspective view illustrating an exemplary embodiment of a conventional rotation slot milling cutter,  FIG. 1B  is a detail view illustrating a portion A of  FIG. 1A  and illustrating an insert mounting seat structure,  FIG. 1C  is a perspective view of a conventional cutting insert, and  FIG. 1D  is a diagram illustrating a state of inserting and processing a cutting insert into a slot of a work material. 
     In general, in a rotation slot milling cutter  1 , a plurality of cutting inserts  13  and  15  are provided in a circumference of a slot milling cutter body  11 , as shown in the drawings, and one  13  (or  15 ) of every two cutting inserts  13  and  15  is protruded at one side surface of the milling cutter body  11 , and the remaining one  15  (or  13 ) is protruded at an opposite side surface of the milling cutter body  11 . 
     As shown in  FIG. 1C , the conventional cutting inserts  13  and  15  have a structure in which a fastening through hole  13   b  is formed at the center thereof and in which a cutting edge  13   a  is formed at one side thereof along a circumference of a body portion of an approximately quadrangular hexahedron shape. An upper surface and a lower surface of the body portion are formed in a flat surface. 
     Further, a state of cutting a work material  30  using a conventional rotation slot milling cutter  1  is shown in  FIGS. 2A and 2B , and  FIGS. 2A and 2B  illustrate a state in which an end portion of the slot milling cutter  1  is inserted into a slot of the work material  30 . 
     Particularly, when a cutting edge of a thin width is formed in a radius R shape, a length of an edge portion is reduced by an R value, and thus a shape thereof is changed and distinguished according to a location that couples a cutting insert to both sides (the left side and the right side) of a milling cutter body. 
     Referring to  FIG. 2A , when using the conventional rotation slot milling cutter  1 , in a structure of a slot  20  formed in the work material  30 , a surface of a front end portion  21  of a slot concave portion is not flat and forms an inclined shape. Therefore, in order to flatly form the front end portion  21  of a concave portion of the slot  20  formed in the work material  30 , one surface of the cutting insert should have a surface of a bending shape. 
     Further, for a smooth slot milling processing, upon processing, a side surface of a cutting insert should form a predetermined allowance angle, and for a required width processing of a slot, it is necessary to prevent confusion of use according to a difference on a shape basis of a cutting insert coupled to a cutting insert mounting portion of both sides of a milling cutter body. 
     Particularly, in a conventional rotation slot milling cutter of  FIG. 1B , as a means for coupling the cutting insert  13  (or  15 ) to the insert mounting seat  11   a  formed in one side of the milling cutter body  11 , a seat protruded member  11   b  of a circular protrusion form is formed. 
     Therefore, the seat protruded member ( 11   b  of  FIG. 1B ) of a circular protrusion shape is inserted into the through hole  11   d  formed at the center of the cutting insert  13  (or  15 ) to be fastened by a separate fastening screw (not shown). 
     However, because the cutting insert  13  (or  15 ) fastened to an insert mounting seat  11   a  of the milling cutter  1  in which the circular seat protruded member  11   b  is formed has a commonly coupled structure regardless of a location of insert mounting seats  11   a  of both sides, the cutting insert may be erroneously mounted. Therefore, there is a problem that damage of a slot milling insert may occur due to part damage of the cutting insert and the slot milling cutter and there is inconvenience in using the slot milling insert. 
     DETAILED DESCRIPTION OF INVENTION 
     Technical Problem 
     The present invention has been made in view of the above problems, and provides an insert for slot milling in which confusion does not occur when a user uses and that has a structure in which left and right shapes of a cutting insert coupled to each of both sides of a milling cutter body are distinguished and in which a cutting insert is not fastened to an insert mounting seat of the opposite side. 
     The present invention further provides an insert for slot milling that can improve a processing quality of a slot by having a radius R shape in an edge portion of a cutting insert while maintaining a flat surface without forming a step at a front end surface of a concave portion of a slot after a slot processing by providing an allowance angle in a cutting insert itself and that can thus enhance customer satisfaction. 
     Technical Solution 
     In accordance with an aspect of the present invention, a cutting insert for slot milling, wherein a plurality of cutting inserts are provided in a circumference of a slot milling cutter body, one of every two cutting inserts is protruded to one side surface of the milling cutter body, the remaining one is protruded to an opposite side surface of the milling cutter body, and the every two cutting inserts are formed in different structures to prevent from being erroneously mounted in an insert mounting seat provided in each of both side surfaces of the milling cutter body. 
     Preferably, the cutting insert has an insert groove on a bottom mounting surface that contacts with the insert mounting seat of the milling cutter, and the insert groove is formed in a polygonal groove shape. 
     Preferably, a polygonal seat protruded member is protruded to an upper portion on an insert mounting seat of the milling cutter to be inserted into an insert groove forming the polygonal groove shape. 
     Preferably, in the seat protruded member, a through hole is formed on an inside central portion thereof, and a helix is formed on an inner circumferential surface of the through hole and thus a stable coupling structure is formed by fastening by screw coupling. 
     Preferably, in the cutting insert, a cutting edge of a cutting insert of one side of every two cutting inserts is rounding processed. 
     Preferably, the cutting insert has a cutting edge at one side thereof along a circumference of a rectangular parallelepiped-shaped body, a through hole for insert coupling at the center thereof, and a space portion of at least one groove form on a protruded surface of the opposite side of an insert fastening surface and thus a cutting load is reduced and a cutting chip is smoothly discharged. 
     Advantageous Effects 
     According to a rotation slot milling cutter of the present invention, as structures of every two cutting inserts of a plurality of cutting inserts coupled to each of both sides of a milling cutter body are differently formed, there is a difference in shapes thereof, and by providing a structure in which an opposite cutting insert is not fastened to insert mounting seats of both sides, damage of a cutting insert and a milling cutter due to erroneous mounting of the cutting insert can be prevented, and a user can conveniently use the rotation slot milling cutter. 
     Further, by providing an allowance angle to a cutting insert itself, after a slot processing, a flat surface is maintained without forming a step in a front end surface of a concave portion of a slot, and by providing a radius shape in an edge portion of a thin width of a cutting insert of one side, a processing quality of the slot is improved and thus customer satisfaction is enhanced. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a perspective view illustrating an exemplary embodiment of a conventional rotation slot milling cutter; 
         FIG. 1B  is a detail view illustrating a portion A of  FIG. 1A  and illustrating an insert mounting seat structure; 
         FIG. 1C  is a perspective view of a conventional cutting insert; 
         FIG. 1D  is a diagram illustrating a state of inserting and processing a cutting insert into a slot of a work material; 
         FIGS. 2A and 2B  are cross-sectional views comparing structures of slots processed by a conventional insert and an insert according to an exemplary embodiment of the present invention; 
         FIG. 3  is a perspective view illustrating a structure of a rotation slot milling cutter in which an insert is mounted according to an exemplary embodiment of the present invention; 
         FIGS. 4A to 4C  are perspective views illustrating a structure of a cutting insert according to an exemplary embodiment of the present invention and a state in which the cutting insert is fastened to an insert mounting seat of a milling cutter; and 
         FIGS. 5A and 5B  each are diagrams illustrating cases in which a cutting insert is rightly mounted and wrongly mounted in a mounting seat of a milling cutter body according to an exemplary embodiment of the present invention. 
     
    
    
     DESCRIPTION OF SYMBOLS 
       1 , 100 : rotation slot milling cutter 
       11 , 110 : milling cutter body  11   a ,  130 : insert mounting seat 
       11 B: seat protruded member (circular)  150 : seat protruded member (polygon) 
       11   d ,  13   b ,  53 ,  155 : through hole  13 ,  15 ,  50 : cutting insert 
       13   a ,  51 : cutting edge  20 ,  20 ′: slot 
       21 ,  21 ′: slot concave portion front end surface  30 : work material 
       50 ,  50 ′: cutting insert  52 : insert groove (polygon) 
     Best Modes for Carrying out the Invention 
     Hereinafter, a rotation slot milling cutter according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 3  is a perspective view illustrating a structure of a rotation slot milling cutter in which an insert is mounted according to an exemplary embodiment of the present invention, and 
       FIGS. 4A to 4C  are perspective views illustrating a structure of a cutting insert according to an exemplary embodiment of the present invention and a state in which the cutting insert is fastened to an insert mounting seat of a slot milling cutter. 
     Further,  FIGS. 5A and 5B  each are diagrams illustrating cases in which a cutting insert is rightly mounted and wrongly mounted in an insert mounting seat of a milling cutter according to an exemplary embodiment of the present invention. 
     First, referring to  FIGS. 3 and 4A to 4C , a cutting insert  50  of the present exemplary embodiment is mounted in a cutting insert mounting seat  130  provided on a main body  110  of a milling cutter  100 , and has an approximately quadrangular hexahedron-shaped body, and a cutting edge  51  is formed at one side corner along a circumference of the body. In this case, the cutting edge  51  is formed in a round processor of a radius shape in a cutting insert of any one side of cutting inserts located at both sides. 
     Further, a groove  54  of a predetermined size is formed on a protrusion surface that contacts with one side surface of each cutting insert  50 , i.e., a work material, and the groove  54  may reduce a cutting load and enable smooth discharge of a cutting chip upon cutting by securing a predetermined allowance space between the cutting insert  50  and the work material upon processing a slot. 
     As shown in  FIGS. 4B and 4C , the cutting insert  50  of the present exemplary embodiment has a structure in which an insert groove  52  of a polygonal shape is formed on a mounting surface mounted in the insert mounting seat  130  of the milling cutter  100 . A polygonal seat protruded member  150  inserted into and coupled to the insert groove  52  to correspond to the insert groove  52  is formed on the cutting insert mounting seat  130  of the slot milling cutter  100  together with forming of the insert groove  52 . 
     This structure enables to couple a cutting insert of both side surfaces of the milling cutter  100 , for example, a right side surface R and a left side surface L of the milling cutter  100  to the insert mounting seat  130  corresponding thereto and prevents an opposite cutting insert  50  (or  50 ′) from being erroneously mounted in the insert mounting seat  130  of the milling cutter  100 . 
     Further, in a structure of the cutting insert  50  of the present exemplary embodiment, each of the insert grooves  52  and  52 ′ of both sides formed on a mounting surface contacting with the cutting insert mounting seat  130  of the milling cutter  100  forms a polygonal shape and thus by differently forming the polygonal structure, erroneous coupling in which the cutting insert  50  coupled to one side surface is mounted in the insert mounting seat  130  of another side surface is prevented. That is, the seat protruded member  150  of the milling cutter  100  coupled to the insert groove  52  formed at one side surface of the cutting insert  50  of the present exemplary embodiment forms a polygon, and when these polygons have different shapes, erroneous mounting of the cutting insert  50  is prevented. 
     Therefore, in a structure of the cutting insert  50  and the slot milling cutter  100  of the present exemplary embodiment, because damage of a cutting insert and a rotation slot milling cutter by erroneous mounting of the cutting insert  50  can be previously prevented, material damage can be previously prevented. 
     The polygonal seat protruded member  150  formed in the insert mounting seat  130  of the present exemplary embodiment operates to solve a structural problem hard to stably mount a fastening screw by low rigidity due to a thin thickness of the cutting insert mounting seat  130  remaining as a problem of a rotation slot milling cutter. That is, the seat protruded member  150  formed on an upper surface of the insert mounting seat  130  has a predetermined thickness, thereby reinforcing a thin thickness of the cutting insert mounting seat  130  of the bottom. 
     In the seat protruded member  150  of the present exemplary embodiment, a through hole  153  for fastening is formed in a central portion of a body  151  having a predetermined thickness, and a helix  155  is formed on an inner circumferential surface of the through hole  153  and thus a fastening force with a fastening screw (not shown) becomes stronger than a conventional case. 
       FIG. 4B (A) is a perspective view illustrating a fastening surface of a cutting insert  50  according to an exemplary embodiment of the present invention, and  FIG. 4B (B) is a top plan view of the insert mounting seat  130  of the milling cutter. 
     Referring to  FIGS. 5A and 5B ,  FIG. 5A  illustrates a case in which a corresponding cutting insert  50  is rightly mounted in the insert mounting seat  130  of the milling cutter, and in this case, the cutting edge  51  of the cutting insert is mounted to correspond with a rotation direction for cutting to appropriately cut. 
     However, in case of  FIG. 5B , when a cutting insert  50 ′ of the opposite side is wrongly mounted in the insert mounting seat  130 , by rotating and mounting a cutting edge  51 ′ that should cut to the opposite side, when cutting, the cutting insert  50 ′ is immediately damaged. 
     Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as defined in the appended claims.