SE526833C2 - Support for coating tool using CVD or MTCVD comprises MAX material to avoid contact mark formation - Google Patents

Abstract

The support comprises a specific MAX material to avoid contact mark formation. A support for a tool being coated using a CVD (Chemical Vapor Deposition) and/or MTCVD (Moderate Temperature Chemical Vapor Deposition) technique comprises a material of formula M n+1AX n. M : one or more metals chosen from Groups IIIB, IVB, VB, VIB or VIII; A : one or more elements chosen from groups IIIA, IVA, VA or VIA; X : C and/or N; and n : 1-3. An independent claim is also included for a CVD or MTCVD method for coating a tool using this support.

Description

25 30 35 s-ssoAsizk 2005-08-08 2 rectangular, octagonal, square, round, triangular, diamond-shaped etc.

The inserts can be manufactured with or without a center hole, with a thickness that varies from 2 mm up to 10 mm. One type of CVD and / or MTCVD coating round will therefore be deposited on as many as hundreds of different geometries of inserts that all need different devices.

Therefore, a batch charging system, which necessarily needs different devices for different cutting geometries to achieve a uniform charging density, will never function further rationally in a production environment focused on low cost and short execution time.

EP 454 686 discloses a charging system, in particular intended for PACVD, where the inserts are stacked on top of each other on a center pin with or without intermediate spacers. Using this method for CVD and / or MTCVD would present several disadvantages as it is not primarily a universal method, as described above, as different insert geometries will need different pin sets. Second, a hole is needed in the inserts. Third, when thick CVD and / or MTCVD layers are applied, the inserts are likely to adhere strongly to the spacer and / or other inserts due to the pressure from the stacked inserts which reinforces the tendency to coalesce.

US 5,576,058 discloses a batch charging system based on various devices of pins comprising a frame part, a shoulder portion, a neck and a head.

A commonly used charging device is to place the inserts in holes or grooves in a washer. This method will give contact marks on the cutting edge or on the cutting surface of the insert. This device needs a very careful treatment during transport and charging of washers to avoid the inserts falling out of position. The device is also very difficult to use when automated cutting placement is used because the inserts have to be placed in very unstable positions. In another method, the inserts are strung on a rod. The rods can be arranged vertically as in EP 454 686 with the same disadvantages as discussed above, or horizontally. The main disadvantages of the horizontal device are the lack of universality for different cutting geometries, so necessarily a large number of different arrangements are needed to manufacture all cutting geometries. In addition, this method can only be applied to inserts with a hole.

The most common devices are based on simply placing the inserts on a surface at necessary intervals either on woven metal mesh 10 15 20 25 30 35 s-590AsEk 2005-08-08 3 or on some other surface (often made of graphite). The kit is built up by stacking the metal nets on top of each other separated by spacers or by using graphite carriers where the nets are placed on top. The major disadvantage of this method so far has been the contact marks between nets and inserts that are always formed. These marks give an incorrect placement of the insert in the tool holder and can lead to a serious deterioration in the performance of the inserts. Often, some finishing, such as sanding, may be needed to remove protruding marks. In addition, marks can be detected on the cutting edge, which is also very negative for the insert's performance. Another disadvantage of using woven nets is that the inserts can slide together relatively easily before coating, thus resulting in uncoated surfaces on the insert.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a carrier body which avoids the formation of contact marks on the inserts during coating.

It is a further object of the present invention to provide a carrier body which avoids contact marks on the inserts during coating.

It is a further object of the present invention to provide a method which avoids contact marks on the inserts during coating.

The objects of the present invention are realized via a method and a carrier body having the properties specified in the characterizing parts of the appended individual claims.

DEFINITIONS In the following description we will use the following terms: Pre-coatings) defines a CVD and / or MTCVD layer applied to the mesh or carrier material before use for the first time when precipitating durable CVD and / or MTCVD layers on the final product, defined herein as growth coatings).

BRIEF DESCRIPTION OF THE FIGURES Figure 1A shows cross-sections of examples of various geometric shapes of a support body according to the present invention that can be used to support inserts. Figure 1B shows some examples of Figure 1A in perspective. Figure 2A shows six examples, in side view, of support bodies according to the present invention having surface patterns that can be used in a support body for single-sided inserts during the coating process.

Figure 2B shows another example of a part of a carrier body according to the present invention in perspective for use in coating single-sided inserts.

DETAILED DESCRIPTION OF THE INVENTION By "MAX phase family" as used herein is meant a material comprising MMAX "(n = 1,2,3) wherein M is one or more metals from groups IIIB, IVB, VB, VIB and VIII of the periodic table of the elements and / or mixture thereof, A is one or fl elements of groups IIIA, IVA, VA and VIA of the Periodic Table and / or mixture thereof of the elements, and wherein X is carbon and / or nitrogen.

Ti3SiC2 is a material in the MAX phase family and is known for its remarkable properties. It is easy to work with, rigid, resistant to thermal shock, resistant to damage, tough, durable at high temperatures, oxidation resistant and corrosion resistant. Still, it has the density of Ti-metal. This material is considered for several applications such as electric heating elements (VVO 02/51208), in contact with molten metals (US 2003075251) and for coating inserts (SE 0202036-0).

According to the present invention, it has surprisingly been found that if the surface of the carrier body (eg pyramids, cones, etc.) which is in contact or in indirect contact with the insert comprises a material selected from the MAX phase family, it is possible to avoid large contact marks and in particular protruding marks. The properties of the carrier body in contact with the inserts substantially eliminate the problem of the prior art.

According to the present invention, the material used in direct or indirect contact with the inserts mainly comprises a material from the MAX phase family as described above, preferably more than 85% by weight.

In one embodiment, M is one or more metals from groups IVB, VB and VIB in the periodic table of the elements.

In another embodiment, A is one or fl era of Si, Al, Ga or Ge.

In another embodiment, the MAX phase is of type n = 2 in MmAXn. In a further preferred embodiment, the MAX phase mainly comprises Ti3SiC2, preferably at least 85% by weight where the residue is one or more of TiC, TiSiz, Ti5Si3 or Sic.

The material is manufactured by methods known in the art as shown in e.g. US 5,942,455.

The carrier body can be manufactured in different geometric shapes to fit into the actual cutting geometry, see Figures 1A and 1B where A, B, C, D and E represent shapes shown in both figures. Each support body has a base or larger surface for contacting a support body, not shown. Usually the insert rests on the carrier body while it has some of it directed into the hole of the insert. The dashed lines in one of the examples represent a double-sided insert to be coated. It should be noted that gravity retains the insert in the carrier body in most cases. For inserts with a central hole, the shape is preferably a pyramid with three or more sides or as a cone. The pyramid corners can also be replaced with a radius between 10 pm and 2 mm. Pyramids with or without radii can also be manufactured with concave and / or convex intermediate side sections.

In order to guarantee a general geometry as independent of the cutting geometry as possible, it is preferred that the exposed sides of the pyramid or cone be straight or made as only a single radius, i.e. convex as a trumpet or concave as a ball.

The pyramids or cones can be truncated to a certain extent to make their handling easier. Truncated pyramids or cones can also be used to support the next load-bearing body.

Truncated pyramids or cones can also be made with a central hole to improve the gas flow pattern. A desired surface unit of the pyramids or cones can also offer an advantage.

For single-sided inserts, i.e. inserts where the underside will never be used, the inserts can be placed directly on a carrier of a material selected from the MAX phase family. This will give thinner layers on the side of the insert towards the carrier, but since that side is not used, there is no significant effect. The surface can then be manufactured either as a flat surface, with or without holes, or as a structural surface. The structural surface can be manufactured as a micro-pattern that varies in height and in plane dimension regularly or irregularly. Figure 2A shows six examples of support bodies according to the present invention having surface patterns that can be used in a support body for single-sided inserts during the coating process. Figure 2B shows another example of a part of a carrier body according to the present invention in a perspective for use in coating single-sided inserts. Figure 2B can represent either macro or microgeometry.

A preferred regular micro-pattern may be pyramids with three or fl sides with a base between 50 μm and 5 mm and a height between 20 μm and 5 mm. A blasting, brushing or scratching method to obtain a microyl fineness, having an Ra value between 50 μm and 500 μm, can give an irregular pattern.

In a preferred embodiment, the support body is precoated with a 5 to 100 μm thick coating of nitride and / or carbide and / or oxide of metals of groups IVB, VB and VIB of the Periodic Table, before use for the first time for production coating.

During use as a support body for supporting inserts for production coating, thicker and thicker coating will be deposited on top of the body. Surprisingly, it has been discovered that this fact does not adversely affect the result. The service life of a carrier body according to the present invention as a carrier material is longer than 50 times the production coating without any reduction in favorable performance.

The insert is intended to be placed on the support body, according to the present invention, made of a material selected from the MAX phase family.

The present invention has been described with reference to inserts, but it is obvious that it can also be used for coating other types of coated components, e.g. drills, end mills, wear parts, etc. At least the surface of the support body where the insert is to rest under the coating comprises a material selected from the MAX phase family. Instead of the whole carrier body consisting essentially of a material from the MAX phase family, it is also conceivable that at least one surface of the carrier body and / or a layer below the surface consists at least partly of a material selected from the MAX phase family. For example, a support body of any material may be coated with at least one surface layer of a material selected from the MAX phase family. The surface layer must be thick enough to avoid contact marks during coating of inserts. The thickness of the surface layer on the support body is at least of the order of 25 μm.

Example 1 Four-sided pyramids with straight corners, see Figures 1A and 1B variant A, with a base of 10 mm side and a height of 7 mm were made of MAX phase material Ti3SiC2 which has small amounts of Ti8C5, hereinafter referred to as variant 10 15 20 25 S -590ASEK 2005-08-08 A-MAX, and of graphite, called variant A-graphite. The pyramids were placed on a flat graphite tray with regularly placed holes of diameter 3 mm.

The pyramids were pre-coated with CVD and MTCVD layers of Ti (C, N) + Al 2 O 3 + TiN with a total thickness of 25 μm. Carbide inserts with the geometry CNMG120408 for the P25 application area were placed on each pyramid of the two variants. A total of 100 pyramids per variant were used.

A CVD / MTCVD production coating of Ti (C, N) + Al 2 O 3 + TiN with an approximately 15 μm total thickness was deposited on the inserts.

After coating, all inserts were examined using a stereo microscope with 10x magnification for marks. The marks were classified according to: no visible marks, visible marks less than 20 μm in height and marks over 20 μm in height. The critical size of 20 μm in height was chosen because that size is the maximum accepted for good performance of the product.

Measured inserts were coated in the first production round after pre-coating. Table 1 below summarizes the results.

Table 1 Number of inserts Number of inserts Number of inserts Degree of without anything with visible with visible adhesion visible marks under marks above mark 20 um 20 um Variant A-MAX 73 27 0 None (invention) Variant A- 0 62 38 Adheres gray (known technique) It can be clearly seen that variant A-MAX had fewer and smaller marks than A-graphite despite the fact that they had the same support body geometry. In addition, pyramids of A-MAX adhere less. This test demonstrates the advantage of a carrier body of a material selected from the MAX phase family.

Example 2 Single-sided cemented carbide inserts with the geometry XOMX0908-ME06 with a composition of 91 wt.% WC - 9 wt.% Co were used. Prior to deposition, the uncoated substrates were made. A CVD production coating of Ti (C, N) + Al 2 O 3 + TiN with an approximately 5 μm total thickness was deposited on the inserts.

The inserts were placed directly on a flat washer, similar to that in Figure 1A at the bottom right but larger. The washer contained a burr carrier body comprising essentially Ti3SiC2 having small amounts of Ti8C5, variant A-MAX, and of graphite, variant A-graphite. The thickness of the sectors was 5 mm. The sectors had been pre-coated with a CVD and MTCVD coating of Ti (C, N) + Al 2 O 3 + TiN to a total thickness of 20 μm before the production coating test.

After production coating, all inserts according to Example 1 were examined.

Measured inserts were coated in the first production coating cycle after pre-coating. Table 2 below summarizes the results.

Table 2 Number of inserts Number of inserts Number of inserts Degree of without anything with visible with visible adhesion visible marks under marks above mark 20 pm 20 pm Variant A-MAX 88 12 0 lngen (invention) Variant A- 0 77 23 Adheres graphite (prior art) The variant A-MAX according to the present invention, clearly shows the best result, the majority of the inserts are completely without any marks, and for those with marks they are less than 20 μm. Also in this example, a clear difference in adhesion can be demonstrated.

Thus, the present invention relates to a method and a support body for coating large quantities of cutting tools and in a rational and productive manner, with hard and durable refractory layers. This method is based on the use of a material selected from the MAX phase family as a sustainable carrier material used in the coating process. In this way, it has been found possible to reduce the disadvantages of known methods, i.e. contact marks.

Claims (10)

10 15 20 25 30 .fl »o s_ \ * O CO CN (N S-590ASEK 2005-08-08 PATENTKRAV A support body intended to support one or more tool inserts when coating the inserts with a CVD and / or an MTCVD method, characterized in that at least one surface of the support body and / or a layer below the surface comprises at least in part a material selected from The MAX phase family, i.e. MMAX "(n = 1,2,3), where M is one or fl your metals from groups ll | B, IVB, VB, VlB and Vlll in the periodic table of the elements and / or mixture thereof, is one or fl your elements from groups lllA, lVA, VA and VIA in the periodic table and / or mixture thereof of the elements, and wherein X is carbon and / or nitrogen. The support body according to claim 1, characterized in that at least the area of the support body where the insert is intended to be under coating comprises a material selected from the MAX phase family. The carrier body according to claim 1 or 2, characterized in that the whole carrier body mainly comprises a material selected from the MAX phase family. The support body according to claim 1 or 2, characterized in that at least one surface layer of the support body mainly comprises a material selected from the MAX phase family. The support body according to claim 4, characterized in that the surface layer is thick enough to avoid contact marks during coating of inserts, where the thickness of the surface layer of the support body is at least of the order of 25 μm. The carrier body according to any one of claims 1-4, characterized in that the carrier body is a pyramid with three or fl sides or a cone. The support body according to claim 6, characterized in that the exposed sides of the pyramid or cone are convex or concave. 10 s-s9oAsEk zoos-os-os 10 The carrier body according to any one of claims 1-7, characterized in that the material from the MAX phase family is TigSiCg. A method of coating tool inserts comprising a substrate and a coating deposited using a CVD and / or MTCVD method, characterized in that the inserts are placed on a support body during the coating as defined in claim 1. The method according to claim 9, characterized in that the support body is arranged substantially of Ti3SiC2 as a pyramid with three or fl sides or a cone by arranging a support body substantially of Ti3SiC2, which has a flat surface with or without a surface pattern.