JP2020066087A5 - - Google Patents

Description

End mill manufacturing method

The present invention relates to a method for manufacturing an end mill.

End mills are widely known as one of the cutting tools. The end mill typically has a main body that rotates about a rotation axis and a cutting blade attached to the surface of the main body.

Japanese Unexamined Patent Publication No. 2016-182658

As a cutting blade of an end mill, it was examined to use a cutting blade having a base made of a cemented carbide material and a sintered diamond layer provided on one surface of the base. When such a cutting blade is cut out from the base material and attached to the end mill main body, the cutting blade warps during cutting, and the warp makes it difficult to attach the cutting blade to the main body. There is.

The present invention has been made to solve the above-mentioned conventional problems, and a main object thereof is to provide a method for manufacturing an end mill capable of suppressing warpage of a cutting blade and satisfactorily attaching the cutting blade to a main body. There is something in it.

The present inventors have different heat shrinkage between the base side made of a cemented carbide material and the sintered diamond layer side due to the laminated structure, so that the heat generated when cutting out the base material causes warpage. I got to know. Then, cut the base material and the base portion made of a superhard material thicker than usual, by cutting a base subsequently, found that can be fabricated cutting blades suppressed Ri reaction that occur during excision, the Completed the invention.
The method for manufacturing an end mill of the present invention is a cutting blade having a predetermined shape by electric discharge machining or laser machining from a base material having a base made of a cemented carbide material and a sintered diamond layer provided on one surface of the base. it is cut to form pieces; by cutting the base of the cutting edge formed strip to reduce the thickness of the base portion, to obtain a cutting edge; and, attaching the cutting blade to the body; comprising a.
In one embodiment, the thickness of the cutting blade forming piece is 1.6 mm to 3.2 mm, and the thickness of the cutting blade is 0.7 mm to 1.6 mm.
In one embodiment, the thickness of the base of the cutting blade forming piece is 1.1 mm to 2.8 mm, and the thickness of the base of the cutting blade is 0.2 mm to 1.3 mm.
In one embodiment, in the manufacturing method, the cutting blade is attached to the main body by sticking.
In another embodiment, the manufacturing method attaches the cutting blade to the body by embedding it in an embedded portion provided in the body. Further, in such a manufacturing method, the cutting blade is fixed to the embedded portion by vacuum brazing in a state where the cutting blade is embedded in the embedded portion.
In one embodiment, cutting the base of the cutting blade forming piece comprises polishing.

According to the present invention, in the manufacturing method of the end mill to attach the cutting blade body having a base portion and a sintered diamond layer, cut out the cutting edge is formed pieces from the base material having a thick base, the base of the cutting edge formed strip cutting and by obtaining the thickness was small and the cutting edges of the base portion, to suppress the warping of the cutting edge, the cutting edge can be realized a method of manufacturing the end mill can be attached well to the body. As a result, it is possible to manufacture an end mill having excellent cutting ability, strength and durability. According to the present invention, since the thick base is cut to make it thinner, the material cost increases, but the manufacturing efficiency as a whole is excellent in consideration of the mountability of the cutting blade to the main body and the resulting strength and durability. It will be. That is, the present invention solves the problem by means that are never adopted by the common general technical knowledge of the industry.

1 (a) is a schematic cross-sectional view illustrating an example of a base material of a cutting blade used in the manufacturing method according to the embodiment of the present invention, and FIG. 1 (b) is a schematic cross-sectional view of the base material of FIG. 1 (a). It is a perspective view. FIG. 2A is a schematic plan view illustrating cutting out of a cutting blade forming piece from a base material in the manufacturing method according to the embodiment of the present invention, and FIG. 2B is a cutout of FIG. 1A. It is a schematic perspective view of the cutting blade forming piece. It is schematic cross-sectional view explaining the manufacturing of the cutting blade in the manufacturing method by embodiment of this invention. FIG. 4A is a schematic plan view illustrating an example of attachment of the cutting blade to the main body in the manufacturing method according to the embodiment of the present invention, and FIG. 4B is a schematic plan view illustrating another example. be. 5 (a) is a schematic plan view illustrating an example of the end mill obtained by the embodiment of FIG. 4 (b), and FIG. 5 (b) is a schematic perspective view of the end mill of FIG. 5 (a). It is a schematic plan view which shows an example of the shape of the non-linearly processed optical film which can be obtained by the manufacturing method of the optical film using the end mill obtained by the manufacturing method of this invention. It is a schematic perspective view for demonstrating the cutting process of the optical film using the end mill obtained by the manufacturing method of this invention. 8 (a) to 8 (e) are schematic plan views illustrating a series of non-linear cutting procedures, which is an example of cutting of an optical film using an end mill obtained by the manufacturing method of the present invention. Is.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. The drawings are schematically shown for easy viewing, and the ratios of length, width, thickness, etc., angles, etc. in the drawings are different from the actual ones.

A. Overall of End Mill Manufacturing Method The end mill manufacturing method of the present invention is to perform electric discharge machining or laser machining from a base material having a base made of a cemented carbide material and a sintered diamond layer provided on one surface of the base. it is cut out of the cutting edge is formed pieces of a predetermined shape by, by cutting the base of the cutting edge formed strip to reduce the thickness of the base portion, to obtain a cutting edge; and, attaching the cutting blade to the body; including .. Hereinafter, each step will be described in order.

B. Base material First, prepare the base material. 1 (a) is a schematic cross-sectional view illustrating an example of a base material of a cutting blade used in the manufacturing method according to the embodiment of the present invention, and FIG. 1 (b) is a schematic cross-sectional view of the base material of FIG. 1 (a). It is a perspective view. As described above, the base material 10 has a base portion 12 made of a cemented carbide material and a sintered diamond layer 14 provided on one surface of the base portion 12. The base metal 10 may have any suitable shape. For example, the base material 10 may have a disk shape (circular in a plan view) as shown in the illustrated example.

A typical example of the cemented carbide material constituting the base 12 is a cemented carbide. Cemented carbide typically refers to a composite material obtained by sintering carbides of Group IVa, Va, and VIa of the Periodic Table with iron-based metals such as Fe, Co, and Ni. Specific examples of cemented carbides include WC-Co alloys, WC-TiC-Co alloys, WC-TaC-Co alloys, WC-TiC-TaC-Co alloys, WC-Ni alloys, and WC-Ni. -Cr-based alloys can be mentioned. The sintered diamond constituting the sintered diamond layer 14 is typically a polycrystalline diamond obtained by baking small grains of diamond together with a binder (for example, metal powder or ceramic powder) at high temperature and high pressure. The characteristics of sintered diamond can be adjusted by changing the type and blending ratio of the binder.

The thickness of the base metal 10 is, for example, 1.6 mm to 3.2 mm, preferably 1.6 mm to 2.4 mm. When the thickness of the base material is within such a range, it is possible to suppress the warp of the cutting blade forming piece when the cutting blade forming piece is cut out from the base material, and thus the warp of the obtained cutting blade can be suppressed. It can be suppressed. As a result, the cutting blade can be successfully attached to the end mill body.

The thickness of the base 12 is, for example, 1.1 mm to 2.8 mm. When the thickness of the base is within such a range, warpage of the cutting blade forming piece can be suppressed when the cutting blade forming piece is cut out from the base material, as described above, and the resulting cutting can be obtained. It is possible to suppress the warp of the blade. As a result, the cutting blade can be successfully attached to the end mill body. The thickness of the sintered diamond layer 14 is, for example, 0.2 mm to 2.8 mm, preferably 0.2 mm to 1.0 mm, and more preferably 0.3 mm to 0.8 mm.

The base metal 10 can be made by a well-known and conventional method in the industry.

C. Cutting out the cutting blade forming piece Next, as shown in FIG. 2A, the cutting blade forming piece 20 is cut out from the base metal 10. Cutting of the cutting blade forming piece is performed by electric discharge machining or laser machining. The electric discharge machining is not particularly limited, and for example, wire-cut electric discharge machining or die-sinking electric discharge machining can be used. Wire-cut electric discharge machining is performed by, for example, using a metal wire as an electrode and immersing the base metal in a processing liquid to generate a discharge phenomenon between the base metal and the electrode to melt and remove the base metal. The die-sinking electric discharge machining is performed so that, for example, a graphite electrode or a copper electrode formed in a shape corresponding to the shape to be formed on the base material is brought close to the base material. Laser processing is performed by cutting out the base metal with laser light. As shown in FIG. 2B, the cut-out cutting blade forming piece 20 has a base portion 12 similar to that of the base material and a sintered diamond layer 14. The thickness of the cutting blade forming piece, the thickness of the base, and the thickness of the sintered diamond layer are as described in Section B above with respect to the base metal.

The cutting blade forming piece 20 typically has a rectangular plan view shape as shown in FIG. 2 (b). By having such a shape, a cutting blade having a desired shape can be manufactured by cutting the base portion as described later. The length L of the cutting blade forming piece 20 can correspond to the length of the obtained cutting blade. By cutting out the cutting blade forming piece from the base material as described above , the cutting blade forming piece (finally, the cutting blade ) can be made into a seamless integral piece along the length direction. As a result, it is possible to produce a cutting blade (finally, an end mill) having excellent cutting ability, strength and durability. The length L of the cutting blade forming piece 20 is preferably 15 mm or more, and more preferably 20 mm to 50 mm. With such a length, when cutting an optical film using the obtained end mill, it is possible to cut a work in which a desired number of optical films are laminated, so that the efficiency of cutting is improved. be able to.

D. Manufacture of cutting blade (cutting of base)
Next, as shown in FIG. 3, the cutting blade 30 is obtained by cutting the base 12 of the cutting blade forming piece 20 to reduce the thickness thereof. That is, the thickness of the cutting blade 30 is smaller than the thickness of the base material 10 (thickness of the cutting blade forming piece 20). Cutting can typically be done by polishing. Polishing is performed by polishing the surface of the base 12 with a flat surface grinding machine. However, the cutting is not limited to polishing, and other methods may be used. For example, it may be milled, latheed, or wire-cut.

The obtained cutting blade 30 has a cut base portion 16 (hereinafter, simply referred to as a base portion 16 or a cutting blade base portion 16) and a sintered diamond layer 14. The thickness of the cutting blade 30 is, for example, 0.7 mm to 1.6 mm, preferably 0.75 mm to 1.2 mm. The thickness of the base 16 of the cutting blade 30 is, for example, 0.2 mm to 1.3 mm, preferably 0.4 mm to 0.9 mm. The thickness of the base 16 of the cutting blade 30 is smaller than the thickness of the base 12 of the base material 10 (the thickness of the base 12 of the cutting blade forming piece 20). The ratio _d 14 _{/ d 16} of the thickness of the sintered diamond layer 14 and the base 16 of the cutting edge 30 is preferably 70% to 400%, more preferably 100% to 300%. When the ratio d ₁₄ / d ₁₆ is in such a range, it is possible to obtain an advantage that the strength as a cutting tool can be secured while suppressing the warp at the time of brazing.

E. Attaching the cutting blade to the main body (manufacturing an end mill)
Next, as shown in FIG. 4A or FIG. 4B, the obtained cutting blade 30 is attached to the end mill main body 40. The main body 40 can be manufactured, for example, by processing a sintered body obtained by a powder metallurgy method well known in the art into a predetermined shape (for example, a cylindrical shape) by a method well known in the industry.

In one embodiment, as shown in FIG. 4A, the cutting blade 30 is attached to the main body 40 by sticking. In the present invention, since the warp of the cutting blade is suppressed, such pasting is possible. In the present embodiment, the main body 40 is formed with a mounting surface 42. The mounting surface 42 can be formed on the body 40 by any suitable method (eg, cutting). The pasting is typically performed by brazing (eg, vacuum brazing or high frequency brazing).

In another embodiment, as shown in FIG. 4B, the cutting blade 30 is embedded in the embedded portion 44 provided in the main body 40 (typically, the cutting blade 30 is inserted into the embedded portion 44). Is attached to the main body 40. In the present invention, since the warp of the cutting blade is suppressed, such embedding is possible. Further, if the configuration is as shown in FIG. 4B, the cutting ability, strength and durability can be improved. The embedding portion 44 can be formed by any suitable method. Specific examples of the forming method include laser processing and cutting processing. The depth of the embedded portion 44 is preferably 0.30 mm to 1.50 mm, more preferably 0.30 mm to 1.00 mm, and further preferably 0.30 mm to 0.70 mm. If the depth of the embedded portion is within such a range, both the strength of the cutting blade to be fixed to the main body and the strength of the main body itself can be ensured. Preferably, the cutting blade 30 is fixed to the embedded portion 44 by vacuum brazing in a state of being embedded in the embedded portion 44. With such a configuration, cutting ability, strength and durability can be further improved. Vacuum brazing can satisfactorily adhere to the main body (embedded portion) even with a cutting blade containing a sintered diamond layer. This is because residual oxygen and water during brazing can be removed, and therefore the oxide film on the surface of the main body can be destroyed and the regeneration of the oxide film can be prevented, so that the wettability of the surface of the main body can be increased.

In the illustrated example, the embodiment in which the number of cutting blades is two has been described, but the number of cutting blades may be one or three or more (for example, three or four). The number of cutting blades is preferably 2 to 3. With such a configuration, the distance between the cutting blades is appropriately secured, so that cutting debris can be satisfactorily discharged. More preferably, the number of cutting blades is two. With such a configuration, the rigidity of the cutting edge is ensured, or One pocket can be satisfactorily discharged cutting dust is ensured.

Further, in the illustrated example, the embodiment in which the cutting edge of the cutting blade is flat has been described, but the cutting edge may be sharp (for example, in FIGS. 4A and 4B, the apex of the acute angle in a plan view is formed. You may have). The cutting edge can be sharpened by any appropriate cutting process.

As described above, an end mill can be manufactured.

F. End Mill FIG. 5 (a) is a schematic plan view illustrating an example of an end mill obtained by the embodiment of FIG. 4 (b), and FIG. 5 (b) is a schematic perspective view of the end mill of FIG. 5 (a). .. The end mill 100 in the illustrated example has a main body 40 that rotates about a rotation shaft 46 extending in a vertical direction (a work laminating direction, a work is a cutting object in which optical films are laminated, and details will be described later), and a main body 40. It has a cutting blade 30 that protrudes from and is configured as the outermost diameter. The end mill is typically a straight end mill. In the illustrated example, the main body 40 is provided with an embedded portion 44, and the cutting blade 30 is embedded in the embedded portion 44 and fixed to the main body 40. With such a configuration, even if the end mill has a small diameter and it is difficult to sufficiently secure a mounting surface for the cutting blade on the surface of the main body, the cutting blade can be satisfactorily mounted on the main body. Therefore, it is possible to actually manufacture a small-diameter end mill having a practically acceptable cutting ability. Further, it is possible to realize an end mill having excellent strength and durability. When a plurality of embedded portions are provided, the embedded portions are preferably provided at positions symmetrical with respect to the rotation axis 46. With such a configuration, good cutting can be achieved and the strength and durability of the end mill can be further improved.

In the end mill of the illustrated example, the helix angle of the cutting blade 30 is typically 0 °. With such a configuration, the optical film described later can be satisfactorily cut. More specifically, when cutting using a cutting blade having a twist angle (for example, deformed or non-linear machining), the cutting surface may be tapered when viewed from the lateral direction, and the twist angle is 0 °. By using a cutting blade, it is possible to prevent the cutting surface from becoming tapered. Here, the irregular shape processing means, for example, processing an optical film into a shape other than a rectangle. In particular, a remarkable effect can be obtained when fine non-linear processing (deformed processing) is performed on an optical film using a small-diameter end mill. In the present specification, "the helix angle is 0 °" means that the cutting blade 30 extends in a direction substantially parallel to the rotation axis 46, in other words, the blade is not twisted with respect to the rotation axis. To say. In addition, "0 °" means that it is substantially 0 °, and includes the case where the angle is slightly twisted due to a processing error or the like.

The outer diameter of the end mill in the illustrated example is typically less than 10 mm, preferably 3 mm to 9 mm, and more preferably 4 mm to 7 mm. According to the embodiment of the present invention, it is possible to actually manufacture an end mill having such a small outer diameter and having a practically acceptable cutting ability. As a result, for example, in fine non-linear processing (deformed processing) of an optical film using such a small-diameter end mill, cracks and yellow bands of the optical film can be satisfactorily suppressed, and further, the optical film has an adhesive layer. When it has, the adhesive chipping can be satisfactorily suppressed. In the present specification, the "outer diameter of the end mill" means that the distance from the rotating shaft 46 to the cutting edge 30a is doubled.

The cutting blade 30 typically includes a cutting edge 30a, a rake face 30b, and a relief surface 30c. The rake face 30b is located on the downstream side in the rotation direction R, and the pocket 50 may be defined by the rake face 30b and the main body 40. The relief surface 30c (base 16), where the surface of the sintered diamond layer 14 corresponds to the rake face 30b and the surface of the base 16 corresponds to the relief surface 30c, is preferably roughened. As the roughening process, any appropriate process can be adopted. A typical example is blasting. When the optical film is cut by roughening the relief surface and the optical film contains an adhesive layer (for example, an adhesive layer or an adhesive layer), an adhesive to a cutting blade or an adhesive or an adhesive to the cutting blade is used. Adhesion of the adhesive can be suppressed and, as a result, blocking can be suppressed. As used herein, the term "blocking" refers to a phenomenon in which optical films in a work adhere to each other with an adhesive or an adhesive on an end face when the optical film contains an adhesive layer, and scraping of the adhesive or the adhesive attached to the end face. The residue contributes to the adhesion between the optical films.

G. Method of Using End Mill The end mill obtained by the production method of the present invention can be typically preferably used in the method of producing an optical film. The manufacturing method preferably includes cutting the end face of the optical film.

Specific examples of the optical film include a polarizing element, a retardation film, a polarizing plate (typically, a laminate of a polarizing element and a protective film), a conductive film for a touch panel, a surface-treated film, and for the purpose of these. Examples thereof include a laminated body appropriately laminated (for example, a circularly polarizing plate for antireflection and a polarizing plate with a conductive layer for a touch panel). In one embodiment, the optical film comprises an adhesive layer (eg, an adhesive layer, an adhesive layer). By using the end mill according to the embodiment of the present invention, it is possible to suppress the adhesive chipping in the cutting process even in the optical film including the adhesive layer.

Hereinafter, a manufacturing method when a polarizing plate with an adhesive layer is used as an example of an optical film will be described. Specifically, each step in the method for manufacturing a polarizing plate with a planar pressure-sensitive adhesive layer as shown in FIG. 6 will be described. It is obvious to those skilled in the art that the optical film is not limited to the polarizing plate with the pressure-sensitive adhesive layer and that the planar shape of the polarizing plate with the pressure-sensitive adhesive layer is not limited to the planar shape shown in FIG. That is, the end mill obtained by the production method of the present invention can be applied to the production method of any optical film having an arbitrary shape.

G -1. Forming of Work FIG. 7 is a schematic perspective view for explaining the cutting process of an optical film, and the work 200 is shown in this figure. As shown in FIG. 7, a work 200 in which a plurality of optical films (polarizing plates with an adhesive layer) are stacked is formed. Since the polarizing plate with an adhesive layer can be manufactured by a method well known in the industry, detailed description of the manufacturing method will be omitted. The polarizing plate with an adhesive layer is typically cut into an arbitrary appropriate shape when forming a work. Specifically, the polarizing plate with an adhesive layer may be cut into a rectangular shape, may be cut into a shape similar to the rectangular shape, and may be cut into an appropriate shape (for example, a circle) according to the purpose. It may have been done. In the illustrated example, the polarizing plate with the pressure-sensitive adhesive layer is cut into a rectangular shape, and the work 200 has outer peripheral surfaces (cutting surfaces) 200a and 200b facing each other and outer peripheral surfaces (cutting surfaces) 200c and 200d orthogonal to them. Have. The work 200 is preferably clamped from above and below by clamping means (not shown). The total thickness of the work is preferably 10 mm to 50 mm, more preferably 15 mm to 25 mm, and even more preferably about 20 mm. With such a thickness, it is possible to prevent damage due to pressing by the clamping means or impact during cutting. The polarizing plates with the pressure-sensitive adhesive layer are stacked so that the workpieces have such a total thickness. The number of polarizing plates with an adhesive layer constituting the work may be, for example, 20 to 100. The clamping means (for example, a jig) may be made of a soft material or a hard material. When composed of a soft material, its hardness (JIS A) is preferably 60 ° to 80 °. If the hardness is too high, imprints may remain due to the clamping means. If the hardness is too low, the jig may be deformed and misaligned, resulting in insufficient cutting accuracy.

G- 2. End mill processing Next, a predetermined position on the outer peripheral surface of the work 200 is cut by the end mill 100. The end mill 100 is typically held by a machine tool (not shown), is rotated at high speed around the rotation axis of the end mill, and is sent out in a direction intersecting the rotation axis while moving a cutting blade to the outer peripheral surface of the work 200. It is used by making it abut and making a cut. That is, the cutting is typically performed by bringing the cutting blade of the end mill into contact with the outer peripheral surface of the work 200 to make a cut. When producing a polarizing plate with an adhesive layer having a plan view shape as shown in FIG. 6, chamfered portions 200E, 200F, 200G, and 200H are formed at four corners of the outer periphery of the work 200, and the chamfered portions 200E and 200E are formed. A recess 200I is formed in the central portion of the outer peripheral surface connecting the 200H.

The cutting process of the work 200 will be described in detail. First, as shown in FIG. 8A, the portion where the chamfered portion 200E of FIG. 6 is formed is chamfered, and then, as shown in FIGS. 8B to 8D, the chamfered portion 200F, The portions where 200G and 200H are formed are chamfered in sequence. Finally, as shown in FIG. 8 (e), the recess 200I is formed by cutting. In the illustrated example, the chamfered portions 200E, 200F, 200G and 200H, and the recesses 200I are formed in this order, but these may be formed in any appropriate order.

The cutting conditions can be appropriately set according to the configuration of the polarizing plate with the pressure-sensitive adhesive layer, the desired shape, and the like. For example, the rotation speed (rotation speed) of the end mill is preferably less than 25,000 rpm, more preferably 22,000 rpm or less, and further preferably 20,000 rpm or less. The lower limit of the rotation speed of the end mill can be, for example, 10000 rpm. Further, for example, the feed rate of the end mill is preferably 500 mm / min to 10000 mm / min, more preferably 500 mm / min to 2500 mm / min, and even more preferably 800 mm / min to 1500 mm / min. Further, for example, the depth of cut of the end mill is preferably 0.8 mm or less, more preferably 0.3 mm or less. The number of cuts of the cut portion by the end mill can be one-time cutting, two-time cutting, three-time cutting or more.

As described above, a polarizing plate with a pressure-sensitive adhesive layer that has been machined can be obtained by using the end mill obtained by the production method of the present invention. In the illustrated example, a polarizing plate with an adhesive layer including a non-linearly processed portion can be obtained.

The end mill obtained by the production method of the present invention can be suitably used for cutting an optical film. The optical film machined by the end mill of the present invention can be used, for example, in an instrument panel of an automobile or a deformed image display unit represented by a smart watch.

10 Base material 12 Base of cutting blade forming piece 14 Sintered diamond layer 16 Base of cutting blade 20 Cutting blade forming piece 30 Cutting blade 30a Cutting edge 30b Scooping surface 30c Escape surface 40 Main body 42 Mounting surface 44 Embedded part 46 Rotating shaft 50 Pocket 100 End mill 200 work

Claims (7)

Cutting out a cutting blade forming piece having a predetermined shape by electric discharge machining or laser machining from a base material having a base made of a cemented carbide material and a sintered diamond layer provided on one surface of the base.
To reduce the thickness of the base portion by cutting the base of the cutting edge forming member, to obtain a cutting edge; and
Attaching the cutting blade to the body;
How to make an end mill, including. The method for manufacturing an end mill according to claim 1 , wherein the thickness of the cutting blade forming piece is 1.6 mm to 3.2 mm, and the thickness of the cutting blade is 0.7 mm to 1.6 mm. The method for manufacturing an end mill according to claim 1 or 2 , wherein the thickness of the base of the cutting blade forming piece is 1.1 mm to 2.8 mm, and the thickness of the base of the cutting blade is 0.2 mm to 1.3 mm. .. The method for manufacturing an end mill according to any one of claims 1 to 3, wherein the cutting blade is attached to the main body by sticking. The method for manufacturing an end mill according to any one of claims 1 to 3, wherein the cutting blade is attached to the main body by embedding it in an embedded portion provided in the main body. The method for manufacturing an end mill according to claim 5, wherein the cutting blade is fixed to the embedded portion by vacuum brazing while the cutting blade is embedded in the embedded portion. The method for manufacturing an end mill according to any one of claims 1 to 6, wherein the cutting of the base of the cutting blade forming piece includes polishing.