FIELD OF THE INVENTION
[0001] The present invention relates to a cutting insert and a cutting tool holder for retaining the cutting insert or multiple cutting inserts, in general, and to a cutting insert and cutting tool for multi grooving and parting operations, in particular.
BACKGROUND OF THE INVENTION
[0002] Metal cutting tools used in turning operations include cutting inserts which are removably secured in a tool holder. The cutting inserts are usually formed of a suitably hard material, i.e., cemented carbide, where the tool holder is formed of a less hard material, and is reusable following the disposal of a worn or damaged cutting insert. In particular, metal cutting tools for multi grooving and parting capable of simultaneously cutting multiple grooves in a work piece, having a holder for retaining a plurality of replaceable cutting inserts therein in a side by side seating. The cutting inserts must be accurately aligned with respect to one another, to assure preciseness and repeatability.
[0003] Some cutting inserts and tool holders have arrangements for positioning the cutting insert in a desired location in the cutting tool, or for determining the extent of entry of the cutting insert into the tool holder. Some cutting inserts have a central opening for receiving a tightening screw, either centrally or at the side of the opening. Examples of such cutting tools and cutting inserts are disclosed in
DE9218472U1,
DE102005014121A1,
DE102006017458A1,
DE202011105832U1,
DE9002895U1,
GB2085333,
US3662443,
US6702524,
US6612207,
US6767168,
US6227771,
US6872033,
US2011/293382,
US2011/0305532, and
BRPI0805470.
[0004] It is an object of the present invention to provide an improved cutting insert for multi grooving and parting applications, and a cutting tool with a tool holder retaining such a cutting insert or a plurality of such cutting inserts. Each cutting insert has a clamping portion with two resilient beams and a flexibility aperture, to allow elastic deformation of the cutting insert in the vertical direction. This allows the tool holder to retain a plurality of cutting inserts, overcoming a case of different insert heights.
SUMMARY OF THE INVENTION
[0005] In accordance with one aspect of the present invention, there is provided an indexable cutting insert having an insert longitudinal axis, an insert lateral axis and an insert vertical axis, the cutting insert comprising:
two opposite insert end surfaces, and a peripheral surface extending
therebetween;
two opposite cutting portions and a clamping portion located therebetween,
arranged along the insert longitudinal axis,
wherein:
each of the cutting portions comprises a rake surface a front relief flank and
two side relief flanks, with a cutting edge formed at an intersection of the rake surface and the front relief flank, the side relief flanks defining a first width;
the clamping portion does not include the cutting edges, and comprises:
first and second side abutment surfaces extending between the two insert
end surfaces, the first and second side abutment surfaces defining a second width , the second width being greater than the first width,
two opposite elongated resilient beams with a flexibility aperture therebetween, the flexibility aperture opening out to the first and second side abutment surfaces, each of the resilient beams is located between a respective one of the insert end surfaces and the flexibility aperture, the flexibility aperture being spaced apart from the cutting portions,
the only resilient portions of the cutting insert are the two resilient beams.
[0006] In accordance with another aspect of the present invention, there is further provided a cutting tool comprising a tool holder and at least one cutting insert as described above.
[0007] The tool holder comprises:
an upper retainer having an upper retainer clamping surface;
a base retainer having at least a first base retainer clamping surface;
an insert receiving pocket defined between the upper retainer and the base retainer, and having a front end and a rear end; and
a holder top surface extending above the upper retainer in a side view of the tool holder,
the at least one cutting insert is retained within the insert receiving pocket, with one of the insert end surfaces being located adjacent the upper retainer clamping surface, and the other one of the insert end surfaces abutting the at least first base retainer clamping surface,
the cutting tool has a first state and a second state, where in the first state each of the at least one cutting insert is in a non-clamped position, and in the second state the at least one cutting insert is in a clamped position,
in the first state of the cutting tool no force is applied on the holder top surface, and in the second state of the cutting tool a force is applied on the holder top surface, and the upper retainer clamping surface is pressed against the adjacent insert end surfaces of each of the at least one cutting insert along the respective resilient beam and the respective resilient beams of each of the at least one cutting insert bends towards the base retainer.
[0008] In accordance with yet a further aspect of the present invention, there is provided an insert stack comprising a plurality of indexable cutting inserts as described above, wherein the cutting inserts are arranged side by side, with a given side abutment surface of each of the cutting inserts abutting a different side abutment surface of an adjacent one of the cutting inserts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a better understanding, the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 is a perspective view schematic illustration of a cutting tool in accordance with an embodiment of the present invention, in an assembled state;
Fig. 2 is a perspective view schematic illustration of the cutting tool of Figure 1, in a non-assembled state;
Fig. 3 is a side view of the cutting tool of Figure 1;
Fig. 4 is a side view of the cutting tool of Figure 2;
Fig. 5 is a perspective view of a cutting insert of the cutting tool of Figure 1;
Fig. 6 is another perspective view of a cutting insert of the cutting tool of Figure 1;
Fig. 7 is a side view of the cutting insert of Figure 5;
Fig. 8 is a top view of the cutting tool of Figure 1; and
Fig. 9 is a side view schematic illustration of a cutting tool in accordance with another embodiment of the present invention, in an assembled state.
[0010] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present invention relates to an indexable cutting insert, and a cutting tool having a tool holder for retaining at least one cutting insert in an insert receiving pocket. The cutting tool may include a plurality of cutting inserts, arranged side by side in a tight stack, and forming a series of spaced apart cutting edges. The cutting insert has two opposite cutting portions and a clamping portion therebetween. Each cutting portion includes a cutting edge of a first width. The clamping portion is limited between two side abutment surfaces, defining a second width, greater than the first width. The clamping portion also has two resilient beams with a flexibility aperture formed therebetween and opening out to the side abutment surfaces. Further, the cutting insert may include two opposite stopper portions for abutting a corresponding holder stopper portion, preventing the cutting insert from moving further into the insert receiving pocket. The cutting tool is for performing metal cutting machining operations, and the cutting insert is usually formed of a hard metal, such as pressed cemented carbide, cermet, and the like.
[0012] Reference is made to Figure 1, depicting a schematic illustration of a cutting tool
150, in an assembled state, herein also referred to as a second state. Figure 2 depicts a schematic illustration of the cutting tool
150 of Figure 1, in a non-assembled state, herein also referred to as a first state. Figures 3 and 4 are side views of the cutting tool
150 of Figures 1 and 2, respectively. The cutting tool
150 includes a tool holder
152 and at least one cutting insert
100. The tool holder
152 includes an upper retainer
154, a base retainer
158 and an insert receiving pocket
166 defined therebetween. The upper retainer
154 has an upper retainer clamping surface
156. The base retainer
158 has at least a first base retainer clamping surface
160. Optionally, the base retainer
158 may also have a second base retainer clamping surface
162, spaced apart from the first base retainer clamping surface
160 ), and extending parallel thereto. The insert receiving pocket
166 has an open front end
170 and a closed rear end
172.
[0013] A holder top surface
155 extends above the upper retainer
154 in a side view of the tool holder
152. In some embodiments, the holder top surface
155 is planar and may be tilted by a first angle α relative to an upper retainer inner surface plane
PI, which is defined by, and may be parallel to the upper retainer clamping surface
156 (Figure 4). Although the tool holder
150 of the embodiment depicted in Figures 1-8 includes both first and second base retainer clamping surfaces
160, 162, it should be understood that a tool holder according to the present invention may include only one base retainer clamping surface (such as the first base retainer clamping surface
160), for example, as depicted in the embodiment of Figure 9.
[0014] With further reference to Figures 5 and 6, the cutting insert
100 is an indexable cutting insert, having an insert longitudinal axis
A, an insert lateral axis
B, and an insert vertical axis
C, the axes being mutually perpendicular, and intersecting at the center of the cutting insert
100. The cutting insert
100 includes two opposite insert end surfaces
102 and a peripheral surface
106 extending therebetween. The insert end surfaces
102 may be perpendicular to the insert vertical axis
C, as indicated, for example, in Figure 7. The cutting insert
100 also has two opposite cutting portions
108, 110 and a central clamping portion
112 located therebetween, and arranged along the insert longitudinal axis
A.
[0015] Each of the cutting portions
108, 110 includes a rake surface
114, a front relief flank
116 and two side relief flanks
118. A cutting edge
120 is formed at an intersection of the rake surface
114 and the front relief flank
116. The side relief flanks
118 define a first width
W1 adjacent the front relief flank
116.
[0016] The clamping portion
112 includes first and second parallel side abutment surfaces
122, 123 extending between the two opposite insert end surfaces
102 and defining a second width
W2 therebetween. The first and second parallel side abutment surfaces
122, 123 may be parallel to the insert longitudinal axis
A. The second width
W2 is greater than the first width
W1. The clamping portion
112 also includes two opposite elongated resilient beams
125 with a flexibility aperture
124 therebetween. The flexibility aperture
124 opens out to the first and second side abutment surfaces
122, 123. Each of the resilient beams
125 extends longitudinally between a respective one of the insert end surfaces
102 and the flexibility aperture
124. The two resilient beams
125 are the only resilient portions of the cutting insert
100. In the present embodiment, the cutting insert
100 includes one flexibility aperture
124, located substantially at the center of the clamping portion
112. Thus, the flexibility aperture
124 is spaced apart from the cutting portions
108, 110, and thus is unsuitable for retaining a cutting insert, unlike insert slots found in holder blades known to those of skill in the art. Likewise, the clamping portion
112 does not include the cutting edges
120 or, for that matter, any sections that cut (i.e., the cutting edges
120 are spaced apart from the clamping portion
112). In some embodiments, the flexibility aperture
124 may have a substantially rectangular shape.
[0017] The flexibility aperture
124 allows the cutting insert
100 to elastically deform in the vertical direction, along the insert vertical axis
C, as will be elaborated herein below. The flexibility aperture
124 has an inner wall
127. The inner wall
127 may be a continuous wall forming a closed contour, in a side view of the cutting insert
100. The inner wall
127 includes at least one longitudinal wall section
131. In some forms of the flexibility aperture
124, the two opposite elongated resilient beams
125 are formed between the longitudinal wall sections
131 of the inner wall
127 and the insert end surfaces
102. Each of the elongated resilient beams
125 has a beam center height
h, which is the distance between the each of the insert end surfaces
102 and the adjacent longitudinal wall section
131, along the insert vertical axis
C (i.e., in a side view of the cutting insert
100). Each of the resilient beams
125 is capable of bending towards the flexibility aperture
124, under an applied force on the respective insert end surface
102, as will be elaborated herein below.
[0018] Each of the resilient beams
125 has a longitudinal beam length
L between two laterally-extending beam end axes
M1, M2, found in the clamping portion
112 on opposite sides of the insert vertical axis
C. The beam end axes
M1, M2 are located where the vertical distance between the respective insert end surface
102 and the inner wall
127 of the flexibility aperture
124 is a maximum beam height
h1. The maximum beam height
h1 is larger than the beam center height
h, for example, by approximately 10-20%. The beam length
L is larger than the beam center height
h, for example, the beam length
L is between 3 to 6 times as large as the beam center height
h.
[0019] According to an embodiment of the present invention, the clamping portion
112 may further includes two opposite stopper portions
126, extending parallel, or substantially parallel to the insert lateral axis
B. Each of the stopper portions
126 is formed on a respective one of the insert end surfaces
102. In a side view of the cutting insert
100, each stopper portion
126 forms a step
128 in the respective insert end surface
102. It is noted, that the stopper portions
126 may be parallel, or substantially parallel to the insert vertical axis
C.
[0020] It is noted, that according to another embodiment of the present invention, the cutting insert
100 includes the two opposite stopper portions
126, and does not include a flexibility aperture
124 therein. That is, the step-like stopper portions
126 may be employed in cutting inserts that have a continuous full clamping portion with no flexibility aperture formed therein.
[0021] An insert height
H extends between the insert end surfaces
102, along the insert vertical axis
C, in a side view of the cutting insert
100. Due to manufacturing differences and tolerances of the cutting insert
100, which is usually formed of a hard metal (e.g., pressed cemented carbide), the insert height
H may vary between different cutting inserts
100.
[0022] In the presently described embodiment and accompanying drawings, the cutting tool
150 includes a plurality of cutting inserts
100, and in particular six cutting inserts
100. However, it should be understood that the cutting tool
150 may include at least one cutting insert
100, without limitation to a particular number of cutting inserts
100.
[0023] The cutting tool
150 has a first non-assembled state and a second assembled state. In the first state each of the cutting inserts
100 is in a non-clamped position, and in the second state the cutting inserts
100 is in a clamped position. In the first state of the cutting tool
150 there is no force applied on the holder top surface
155 and thus no force applied on the insert end surfaces
102. In the non-clamped position of the cutting inserts
100, the resilient beams
125 are in a neutral, unbent, position.
[0024] The tool holder
152 has a holder plane
P passing through the insert receiving pocket
166. The holder plane
P includes a holder lateral axis
Q thereon. The cutting inserts
100 are placed in the insert receiving pocket
166, such that the insert longitudinal and lateral axes
A, B are located in the holder plane
P. Further, the insert lateral axis
B of the cutting inserts
100 coincides with the holder lateral axis
Q.
[0025] When all of the cutting inserts
100 are placed within the insert receiving pocket
166, a force
F is applied on the holder top surface
155, having a vertical force component (i.e., along the vertical axes
C of the cutting inserts
100), moving the cutting tool
150 to the second state. The upper retainer clamping surface
156 is pressed against the adjacent one of the insert end surfaces
102 of the cutting inserts
100, at the clamping portion
112 and along the respective resilient beam
125. The upper retainer clamping portion
156 is the only clamping surface of the upper retainer
154, and thus the cutting insert
100 is clamped only at the clamping portion
112 thereof. That is, the cutting insert
100 is clamped at a spaced apart location from its cutting edges
120. The insert height
H of each cutting insert
100 may be slightly different, due to production tolerances. Thus, the upper retainer clamping surface
156 is pressed until firmly contacting the adjacent one of the insert end surfaces
102 of all of the cutting inserts
100. The force
F may be applied, for example, by a press or clamp member, extending laterally along the holder top surface
155.
[0026] In a case where a certain cutting insert
100 has an insert height
H greater than the other cutting inserts
100, the upper retainer clamping surface
156 would be pressed down against the respective insert end surfaces
102 of that cutting insert
100 along the resilient beam
125 (i.e., in the vicinity of the flexibility aperture
124), thereby bending the resilient beam
125 towards the base retainer
158. In particular, the upper retainer clamping surface
156 would press down against the adjacent resilient beam
125, urging the cutting insert
100 with the greater insert height
H, to elastically deform in the vertical direction, compressing towards the base retainer
158. The resilient beam
125 which is pressed by the upper retainer clamping surface
156, undergoes beam deflection, and bends (i.e., elastically deforms) towards the flexibility aperture
124. In this manner, the upper retainer clamping surface
156 is pressed towards the base retainer
158 until firmly contacting the adjacent one of the insert end surfaces
102 of each of the cutting inserts
100 in the tool holder
152, thereby placing the cutting tool
150 in its second state (i.e., assembled state). It is noted that during the beam bending or deflection of the resilient beam
125, the beam end axes
M1, M2 are substantially static.
[0027] In the second state of the cutting tool
150 (e.g., Figures 1 and 3), the cutting inserts
100 are in the clamped position, retained within the insert receiving pocket
166, with one of the insert end surfaces
102 of each cutting insert
100 abutting the upper retainer clamping surface
156 along the respective resilient beam
125, in the vicinity of the respective flexibility aperture
124. Further, the other one of the insert end surfaces
102 of each cutting insert
100 abuts the first and second base retainer clamping surfaces
160, 162. When a plurality of cutting inserts
100 are employed, the cutting inserts
100 are arranged in an insert stack
119, side by side, such that the first side abutment surface
122 of one of the cutting inserts
100 abuts the second side abutment surfaces
123 of an adjacent cutting insert
100 (e.g., as indicated in Figure 8). In the insert stack
119, a given side abutment surface
122, 123 of each of the cutting inserts
100 abuts a different side abutment surface
123, 122 of the adjacent one of the cutting inserts
100. While Figure 8 shows the cutting inserts
100 in insert stack
119 to be identical, it is also possible for an insert stack to contain cutting inserts with non-identical cutting portions to, for example, fonn grooves of varying shapes or depths adjacent to one another.
[0028] When the cutting inserts
100 are inserted into the insert receiving pocket
166, one of the cutting edges
120 of each cutting insert
100 is an active cutting edge, and the other cutting edge
120 is a non-active cutting edge. The active cutting edge
120 of each of the cutting inserts
100 (in this case, the cutting edge
120 of the cutting portion
108) is located outside the open end
170 of the insert receiving pocket
166. The non-active cutting edge
120 of each one of the cutting inserts
100 (in this case, the cutting edge
120 of the cutting portion
110) is located adjacent the rear end
172 of the insert receiving pocket
166. However, the non-active cutting edge
120 of each one of the cutting inserts
100 does not contact the walls of the insert receiving pocket
166. In this manner, the non-active cutting edge
120 is not subject to clamping forces applied on each of the cutting inserts
100, and thus prevented from mechanical damage, such as possible fracture and breakage during cutting operations.
[0029] Reference is made to Figure 8, depicting a top view of the cutting tool
150. The second width
W2, adjacent the side abutment surfaces, is greater than the first width
W1, adjacent the cutting edges
120 of the cutting inserts
100. A lateral spacing
S is formed between two adjacent cutting inserts
100, in particular, the lateral spacing
S is formed between the same location along each of the cutting edges
120 of the two adjacent cutting inserts
100. In this manner, as seen in the top view (e.g., taken along one of the insert vertical axes
C), or in a front view (e.g., along the holder longitudinal plane
P), the insert stack
119 of cutting inserts
100 forms a series of evenly spaced apart and parallel cutting edges
120. Such a series of adjacent cutting edges
120 is suitable for making parallel uniformly spaced-apart grooves in a work piece, or for cutting out uniform slices of metal, for example, uniform rings of metal beams, pipes and the like. Since the uniform lateral spacing
S is formed by the geometrical structure of the cutting inserts
100, it is not necessary to include additional spacers for laterally separating the cutting insert
100 from one another. The magnitude of the lateral spacing
S is determined according to the first and second widths
W1, W2, which may be formed according to specific requirements of the cutting tool
150 in particular cutting operations (e.g., desired thickness of the metal slices or rings to be cut, and the like).
[0030] The base retainer
158 may further include a lateral recess
164 extending laterally between the first and second base retainer clamping surfaces
160, 162. The lateral recess
164 is an indented recess, extending parallel, or substantially parallel to the holder lateral axis
Q, and thus parallel to the base retainer clamping surfaces
160, 162. The lateral recess
164 ensures that the first and second base retainer clamping surfaces
160, 162 are separated from one another, providing two spaced apart contact regions between the base retainer
158 and the insert end surface
102, which is adjacent the base retainer
158. This provides better clamping of the cutting insert
100 within the insert receiving pocket
166.
[0031] When the cutting inserts
100 are in the clamped position, retained by the upper and base retainers
154, 158, side retainers may be placed at the lateral ends of the insert receiving pocket
166. This may be done in order to prevent the outermost cutting inserts
100 from being extracted from the insert receiving pocket
166 in the lateral direction.
[0032] With further reference to Figure 4, according to an embodiment of the present invention, the base retainer
158 further includes a holder stopper portion
174 extending along the base retainer second clamping surface
162 and parallel, or substantially parallel thereto. The base retainer
158 also includes a raised portion
176, located adjacent the rear end
172 of the insert receiving pocket
166. The holder stopper portion
174 couples the second base retainer clamping surface
162 and the raised portion
176, forming a step-like shape in a side view of the tool holder
152.
[0033] In the embodiment depicted in the drawings, the upper retainer
154 and the base retainer
158 are formed as a one piece unitary construction. In this case, the tool holder
152 may also include a holder elasticity recess
168 extending laterally (i.e., parallel to the holder lateral axis
Q) in the rear end
172 of the insert receiving pocket
166, adjacent the upper retainer
154. The holder elasticity recess
168 allows the upper retainer
154 to elastically move towards and away from the base retainer
158, when force is applied thereon, for example, when clamping the cutting insert
100 (e.g., Figure 3).
[0034] In the embodiment where the clamping portion
112 of each cutting insert
100 includes the insert stopper portions
126, each cutting insert
100 is inserted into the insert receiving pocket
166, until one of the insert stopper portions
126 abuts the holder stopper portion
174. Thereby the holder stopper portion
174 prevents each of the cutting inserts
100 from moving further into the insert receiving pocket
166. Further, all of the cutting inserts
100 are stopped at the holder stopper portion
174, thereby aligning all of the cutting insert
100 in a similar longitudinal position.
[0035] Each insert stopper portion
126 is formed on the clamping portion
112, between the first and second side abutment surfaces
122, 123, and thus it is as wide as the second width
W2. In this manner, the cutting insert
100 is stopped against the holder stopper portion
174, at the wider portion thereof. This provides further stability and strength in stopping the cutting insert
100, as it is stopped against the holder stopper portion
174 at the wider portion thereof.
[0036] Further, each of the insert stopper portions
126 is thus spaced apart from the nearest cutting portion
108, 110. If one of the cutting portions
108, 110 is damaged or breaks during a cutting operation, the cutting insert
100 may still be indexed and retained in the holder
152, with the insert stopper portion
126 abutting the holder stopper portion
174, even in the case where the cutting portion, nearest to that insert stopper portion
126, is damaged.
[0037] It should be appreciated that each of the cutting inserts
100 is an indexable insert, with a rotational symmetry of 180° about the insert lateral axis
B. Therefore, when one of the cutting inserts
100 is indexed, the cutting edge
120 that was active prior to indexing, is located adjacent the rear end
172 of the insert receiving pocket
166 after indexing. The insert end surface
102 that was adjacent the upper retainer
154 prior to indexing, is located adjacent the base retainer
158 after indexing, abutting the first and second base retainer clamping surfaces
160, 162.
[0038] In multi grooving or multi parting tools, the cutting edge wear may be asymmetrical between the various cutting inserts
100. Thus, it could be desirable to index only selected ones of the cutting inserts
100, in which the cutting edge wear is more notable than others. In the present invention, when the force
F is relieved from the holder top surface
155, the cutting inserts
100 are in the non-clamped position, such that each of the cutting inserts
100 may be pulled out of the insert receiving pocket
166 along its longitudinal axis
A, while other cutting inserts
100 are not removed, and then returned after indexing or replaced by a new cutting insert
100.
[0039] When the cutting inserts
100 are arranged in the tool holder
150, the flexibility apertures
124 of the cutting inserts
100 are longitudinally aligned relative to one another, forming a unitary stack aperture
129 (Figure 1). The cutting inserts
100 may be extracted together as a group from the insert receiving pocket
166, for example in order to index the cutting inserts
100. This may be performed with an elongated indexing bar, which can be passed laterally through the stack aperture
129. It is noted that Figure 2 depicts the cutting inserts
100 being located adjacent one another outside the insert receiving pocket
166. However, it should be understood that the cutting inserts
100 may be inserted separately, i.e., one by one, into the insert receiving pocket
166. Alternatively, the cutting inserts
100 may be inserted together as a group into the insert receiving pocket
166, for example, by employing the elongated indexing bar.
[0040] Reference is now made to Figure 9, which depicts a side view of a cutting tool
150', according to another embodiment of the present invention. The cutting tool
150' includes a tool holder
152' and at least one cutting insert
100' retained therein. For example, the cutting tool
150' includes an insert stack
119 of cutting inserts
100'. The differences between this embodiment and the first embodiment of Figures 1-8, is that the cutting inserts
100' do not include the step-like insert stopper portions
126, and the holder
152' has a holder rear stopper
173 formed in the rear end
172 of the insert receiving pocket
166, instead of the step-like holder stopper portion
174. Further, the base retainer
158 includes only the first base retainer clamping surface
160 (i.e., the base retainer
158 does not include the base retainer clamping surface
162). The cutting inserts
100' are inserted into the insert receiving pocket
166, until the front relief flank
116 adjacent the cutting edge
120 which is non-active, abuts the holder rear stopper
173.
[0041] Similarly to the above discussed cutting tool
150 of Figures 1-8, the cutting inserts
100' are retained within the insert receiving pocket
166, such that one of the insert end surfaces
102 of each cutting insert
100' abuts the upper retainer clamping surface
156 along the resilient beam
125, in the vicinity of the respective flexibility aperture
124. Further, the other one of the insert end surfaces
102 of each cutting insert
100' abuts the first base retainer clamping surface
160. When the cutting tool
150' includes an insert stack
119 of cutting inserts
100', a given side abutment surface
122, 123 of each of the cutting inserts
100' abuts a different side abutment surface
123, 122 of the adjacent one of the cutting inserts
100'.
[0042] While the present invention has been described with reference to one or more specific embodiments, the description is intended to be illustrative as a whole and is not to be construed as limiting the invention to the embodiments shown. It is appreciated that various modifications may occur to those skilled in the art that, while not specifically shown herein, are nevertheless within the scope of the invention.
1. An indexable cutting insert (100, 100') having an insert longitudinal axis (A), an insert lateral axis (B) and an insert vertical axis (C), the cutting insert (100, 100') comprising:
two opposite insert end surfaces (102), and a peripheral surface (106)
extending therebetween;
two opposite cutting portions (108, 110) and a clamping portion (112) located
therebetween, arranged along the insert longitudinal axis (A),
wherein:
each of the cutting portions (108, 110) comprises a rake surface (114), a front
relief flank (116) and two side relief flanks (118), with a cutting edge (120) formed at an intersection of the rake surface (114) and the front relief flank (116), the side relief flanks (118) defining a first width (W1);
the clamping portion (112) does not include the cutting edges (120), and
comprises:
first and second side abutment surfaces (122, 123) extending between
the two insert end surfaces (102), the first and second side abutment surfaces (122, 123) defining a second width (W2), the second width (W2) being greater than the first width (W1),
two opposite elongated resilient beams (125) with a flexibility
aperture (124) therebetween, the flexibility aperture (124) opening out to the first and second side abutment surfaces (122, 123), each of the resilient beams (125) is located between a respective one of the insert end surfaces (102) and the flexibility aperture (124), the flexibility aperture (124) being spaced apart from the cutting portions (108, 110),
the only resilient portions of the cutting insert (100, 100') are the two
resilient beams (125).
2. The cutting insert (100, 100') according to claim 1, wherein the clamping portion (112) further comprises two opposite laterally extending stopper portions (126), each formed on a respective one of the insert end surfaces (102).
3. The cutting insert (100, 100') according to claim 2, wherein each stopper portion (126) forms a step (128) in the respective one of the insert end surfaces (102).
4. The cutting insert (100, 100') according to any one of claims 1-3, wherein each of the resilient beams (125) is capable of bending towards the flexibility aperture (124), under an applied force on the respective insert end surface (102).
5. The cutting insert (100, 100') according to any one of claims 1-4, wherein the flexibility aperture (124) has a continuous inner wall (127) forming a closed contour, in a side view of the cutting insert (100, 100').
6. The cutting insert (100, 100') according to claim 4, wherein each of the resilient beams (125) is located between the inner wall (127) and the respective insert end surface (102), each of the resilient beams (125) having a beam center height (h) between the respective insert end surface (102) and the adjacent inner wall (127), measured along the insert vertical axis (C).
7. The cutting insert (100, 100') according to claim 4, wherein
each of the resilient beams (125) has a longitudinal beam length (L) between two laterally extending beam end axes (M1, M2) found in the clamping portion (112) on opposite sides of the insert vertical axis (C), the beam end axes (M1, M2) being located where the respective insert end surface (102) and the inner wall (127) of the flexibility aperture (124) are spaced apart by a predetermined maximum beam height (h1); and
the beam length (L) is between 3 to 6 times as large as the maximum beam height (h1), and, preferably, wherein the maximum beam height (h1) is 10% to 20% larger than the beam center height (h).
8. A cutting tool (150, 150') comprising a tool holder (152, 152') and at least one cutting insert (100, 100') in accordance with any one of claims 1-7.
9. The cutting tool (150, 150') according to claim 8, wherein:
the tool holder (152, 152') comprises:
an upper retainer (154) having an upper retainer clamping surface (156);
a base retainer (158) having at least a first base retainer clamping surface (160);
an insert receiving pocket (166) defined between the upper retainer (154) and the base retainer (158), and having a front end (170) and a rear end (172); and
a holder top surface (155) extending above the upper retainer (154) in a
side view of the tool holder (152, 152'),
the at least one cutting insert (100, 100') is retained within the insert receiving pocket (166), with one of the insert end surfaces (102) being located adjacent the upper retainer clamping surface (156), and the other one of the insert end surfaces (102) abutting the at least first base retainer clamping surface (160),
the cutting tool (150, 150') has a first state and a second state, in the first state each of the at least one cutting insert (100, 100') is in a non-clamped position, and in the second state each of the at least one cutting insert (100, 100') is in a clamped position,
in the first state of the cutting tool (150, 150') no force is applied on the holder top surface (155), and
in the second state of the cutting tool (150, 150') a force (F) is applied on the holder top surface (155), and the upper retainer clamping surface (156) is pressed against the adjacent insert end surfaces (102) of each of the at least one cutting insert (100, 100') along the respective resilient beam (125), and the respective resilient beam (125) of each of the at least one cutting insert (100, 100') bends towards the base retainer (158).
10. The cutting tool (150, 150') according to claim 9, wherein at least two cutting inserts (100, 100') are retained within the insert receiving pocket (166), the cutting inserts (100, 100') being arranged in an insert stack (119), with a given side abutment surface (122, 123) of each of the cutting inserts (100, 100') abutting a different side abutment surface (123, 122) of an adjacent one of the cutting inserts (100, 100').
11. The cutting tool (150, 150') according to any one of claims 9 and 10, wherein the base retainer (158) further comprises a second base retainer clamping surface (162), spaced apart from the first base retainer clamping surface (160), and extending parallel thereto.
12. The cutting tool (150, 150') according to any one of claims 9-11, wherein:
the tool holder (152, 152') has a holder plane (P) passing through the insert receiving pocket (166) and including a holder lateral axis (Q),
when the at least one cutting insert (100, 100') is in the insert receiving pocket (166), the insert longitudinal and lateral axes (A, B) are located in the holder plane (P), and the insert lateral axis (B) coincides with the holder lateral axis (Q).
13. The cutting tool (150) according to any one of claims 9-12, wherein:
the clamping portion (112) of the at least one cutting insert (100) comprises two opposite insert stopper portions (126), each formed on a respective one of the insert end surfaces (102), and extending parallel to the insert lateral axis (B),
the base retainer (158) further comprises a laterally extending holder stopper portion (174), and
one of the insert stopper portions (126) abuts the holder stopper portion (174).
14. The cutting tool (150') according to any one of claims 9-12, wherein:
the insert receiving pocket (166) comprises a holder rear stopper (173) formed in the rear end (172) of the insert receiving pocket (166), and
one of the front relief surfaces (116) of the cutting insert (100') abuts the holder rear stopper (173).
15. An insert stack (119) comprising a plurality of indexable cutting inserts (100, 100') in accordance with claim 1, wherein the cutting inserts (100, 100') are arranged side by side, with a given side abutment surface (122, 123) of each of the cutting inserts (100, 100') abutting a different side abutment surface (123, 122) of an adjacent one of the cutting inserts (100, 100').