T 1874/06 14-07-2009

Reasons for the Decision

1. Admissibility of requests

Main request and auxiliary requests I and II

1.1 The amended main request and auxiliary requests I and II were filed by the appellant at the start of the oral proceedings before the Board. Thus these three requests were filed after the time limit set by the Board in its communication annexed to the summons to oral proceedings wherein the parties were requested to make any submissions at least one month before the oral proceedings and were advised to take note that the admittance of facts and evidence was still subject to the provisions of Article 114(2) EPC and Articles 12 and 13 RPBA (see point V above).

1.1.1 From Article 13(3) RPBA it is clear that amendments to a party's case after the issue of the summons to oral proceedings shall not be admitted if they raise issues which the Board or the other party cannot reasonably be expected to deal with without adjournment of the oral proceedings.

The Board thus examined the amendments and their consequences for the appeal proceedings.

1.1.2 First of all, the respondent did not object to the filing of these three requests at this stage of the proceedings.

1.1.3 Claims 1 to 11 of the main request are identical with those of the former main request. Independent process claim 12 is based on claim 12 of the former main request but principally has been restricted to the materials and tools of claim 1 by incorporating the subject-matter of claims 14 and 15 as granted (see point IX, above).

Claims 1 to 11 of auxiliary request I are identical with claims 1 to 11 of the former auxiliary request while process claim 12 of auxiliary request I is based on claim 12 of the new main request which has been brought into agreement with product claim 1 by adding the feature concerning the stress (see point X, above).

1.1.4 Since the main request and auxiliary request I do not raise any new issues they are admitted into the proceedings.

1.1.5 Claims 1 to 11 of auxiliary request II are based on claims 1 to 3, 7 to 13 and 16 of the main request but the subject-matter of the independent claims 1 and 7 has been restricted to materials consisting of (Ti,Al)N and product claim 1 has been further restricted by introducing an upper limit for the QI value (see point XI, above). Thus this restricted embodiment was already covered by the main request.

1.1.6 Taking account of all these elements the Board therefore decides to admit the main and auxiliary requests I to II into the proceedings.

Auxiliary request III

1.2 At the end of the discussion of inventive step of the subject-matters of product claim 1 and process claim 12 of auxiliary request II, i.e. before the break for deliberation on this issue by the Board, the appellant requested to submit a new auxiliary request III. By this new request, which then was submitted after said break, it attempted to overcome the conclusion of the Board of lack of inventive step with respect to the aforementioned request.

1.2.1 Claims 1 to 3 of auxiliary request III are identical with claims 9 to 11 of auxiliary request II (see point XII, above).

1.2.2 The respondent stated that the reason for submitting this new request at this very late stage of the proceedings was that it only realised during the discussion of inventive step that the claimed product could be obtained in other ways than by the claimed method.

The fact that the appellant submitted a new main request and auxiliary requests I and II at the start of the proceedings shows that it was aware of the risk that the appeal could be dismissed. Therefore it could have filed said auxiliary request III earlier than at that stage of the oral proceedings, which is thus considered as filed very late.

1.2.3 However, since the respondent did also not object to the filing of this new request at the oral proceedings the Board sees no reason not to admit this auxiliary request III into the proceedings.

1.3 Thus the main request and auxiliary requests I to III were admitted into the proceedings and discussed as to their substance.

2. Admissibility of amendments (Articles 123(2) and (3) EPC)

Since the Board comes to the conclusion that the subject-matter of claim 1 of all requests lacks an inventive step (see points 5 below) there is no need to verify whether the amendments comply with Articles 123(2) and (3) EPC.

3. Sufficiency of disclosure (Article 83 EPC)

The Board comes to the conclusion that the patent in suit and particularly the subject-matter of claims 1 and 12 of the main request comply with Article 83 EPC for the following reasons:

3.1 According to feature QI = I(200)/I(111) of claims 1 and 12 the ratio of the intensities (i) of the (200) and (111) peaks of the X-ray diffractogram of the MeX layer is defined with the proviso that the I(200) value to be at least 20 times larger than the "average intensity noise value" which has to be measured with a specific diffractometer and specific settings thereof.

The respondent's arguments that the person skilled in the art does not know what is meant by said feature of "average intensity noise value" cannot hold since noise is a measured random signal and the person skilled in the art knows how to extract non-random signals to be measured from noise. Furthermore, it is specified in both claims to consider only signals which are 20 times larger than the noise and such a signal to noise ratio is always measured against a standard. The person skilled in the art is likewise able to analyse a drifting diffractogram. Fluorescence is considered not to fall under the definition of noise since fluorescence is a well-known physical effect which produces known non-random signals. With respect to Annex B it is remarked that the XRD conditions (see XRD operating parameters: Step: 0.007º Step time: 3813. s) were such that fluorescence occurred, i.e. the sample was radiated with X-rays for a certain time to induce the fluorescence. Such an angular speed of 0.007º/3813 seconds, however, does not fall under the definition of the diffractometer settings of claims 1 and 12 where the angular speed is defined to be 0.05º/min, i.e. 0.05º/60 seconds.

3.2 None of the respondent's arguments concerning the Siemens D500 diffractometer hold, either. First of all, the respondent has not submitted any evidence that on the application date of the patent in suit that this specific diffractometer was not available to the person skilled in the art. As argued by the respondent this diffractometer was a common instrument used by several institutions in Germany at that time so that the person skilled in the art was enabled to carry out measurements including the noise. Furthermore, all diffractometers work with the same source and same principles and thus should in principal produce identical XRD spectrograms so that in scientific papers measuring results are presented without any indication as to how the measurements were carried out.

The respondent's arguments that this instrument nowadays is no longer available or that its software would have been modified and that therefore uncertainty with respect to a possible infringement would exist are not considered being particularly relevant concerning the issue of sufficiency of disclosure. Such infringement proceedings are not relevant to the decision of the Boards of Appeal. In this respect the Board notes that the relevant date for compliance with Article 83 EPC is the application date, not subsequent dates.

3.3 The respondent's arguments concerning the missing teaching with respect to the carbides and carbonitrides cannot hold for the following reasons. The application as originally filed (corresponding to the published WO-A-99 14391) discloses many examples (in total there are 47 examples and comparative examples) on how to produce a nitride film in accordance with the claims 1 and 12 of the main request. According to examples 14 to 16 outermost layers of TiCN and (TiAl)NO as well as an interlayer of TiCN (example 16) were apparently applied with the same arc ion plating apparatus and same method as the deposited interlayers of TiN and the (TiAl)N layers since the outermost Al2O3 layer of examples 17 and 18 is stated to have been deposited by a (different) plasma CVD technique (see WO-A-99 14391, Table 2, and page 9, lines 1 to 21).

Furthermore, the person skilled in the art generally knows how to produce carbides or carbonitrides with the same process parameters of the reactive cathodic arc evaporation technique by merely adding a carbon-containing gas to the nitrogen to obtain the corresponding metal carbonitride, or by replacing the nitrogen with a carbon-containing gas to obtain the corresponding metal carbide. E2A for example applies its teaching onto a huge number of compounds, i.e. carbides, nitrides and carbonitrides of metals from groups 4a, 5a and 6a of the periodic table and Al without giving examples for all of them - actually there are only 12 examples of binary nitrides disclosed - but the person skilled in the art is able to put into practice its teaching.

3.4 The respondent's arguments with respect to the open range of the QI value of at least 5 up to "infinity" cannot hold, either. The examples of the application as originally filed provide QI values up to 22.5 (see Table 1, example 7) and thus it has been demonstrated that high QI values are possible. No evidence to the contrary has been submitted by the respondent. Furthermore, the person skilled in the art is aware of the fact that in practice a QI value of infinity cannot be achieved. The peak for the plane (111) will always be present even if it will be very small and likewise the peak for the plane (200) will not grow to infinity. Consequently, the methods of measurement and of deposition actually set limits for these intensity values and thus for the resulting QI value. As the said example 7 with the high QI value of 22.5 discloses a residual stress of only 1.2 GPa (see Table 1) it is not apparent that the stress range limits the QI value.

4. Novelty (Article 54 EPC)

4.1 Novelty of the subject-matter of the independent product and process claims has not been disputed by the respondent during the appeal proceedings. The Board is satisfied that none of the documents on file discloses either a tool or a method for making a tool having all the features of the independent claims 1 and 12 of the main request.

The Board therefore considers that the subject-matters of independent claims 1 and 12 of the main request are novel (Article 54 EPC).

4.2 The above conclusion applies mutatis mutandis to claims 1 and 12 of auxiliary request I (see point X above), to claims 1 and 9 of auxiliary request II (see point XI, above) and to claim 1 of auxiliary request III which is identical with independent process claim 9 of auxiliary request II (see point XII above), since these claims are narrower in scope than claims 1 and 12 of the main request. Consequently, the subject-matter of the independent claims of auxiliary requests I to III is likewise considered to be novel (Article 54 EPC).

5. Inventive step (Article 56 EPC)

Auxiliary request II

5.1 The Board comes to the conclusion that at least claim 1 of auxiliary request II (which is narrower in scope than claim 1 of the main request) lacks an inventive step over the disclosure of E2A for the reasons which follow:

5.2 E2A is considered to represent the closest prior art with respect to a tool comprising a tool body and a wear resistant layer system comprising at least one hard material MeX coating consisting of (Ti,Al)N, wherein said layer has a QI value > 1.5, with QI = I(200)/I(111) (see paragraphs [0006] and [0010]; Table 1, examples 1 and 7). Said layer system is superior in abrasion resistance and fracture and chipping resistance (see paragraph [0001]). Said tool body is e.g. high speed steel (HSS) (see paragraph [0010]) or a cemented carbide (see paragraph [0007]) and said tool is e.g. a cutting tool insert or tip, or can be an end mill and the like (see paragraphs [0002] and [0011]).

Examples 1 and 7 of E2A were made with a coated cemented carbide 84WC-3TiC-1TiN-3TaC-9vol%Co throw away insert having the tool shape SEE42TN-G9Y at a bias of middle voltage (50-100 V) and high voltage (150-200 V) with nitrogen as reaction gas at a pressure of 10**(-1)Pa; the material to be milled was SDK61 with a cutting speed of 250 m/min, a feed of 0.2 mm/blade and a depth of cut of 2.0 mm which for the 3 µm thick coating of (Ti, Al)N and a QI value of 2.3 resulted in a cutting length of 2.9 m (at a maximum abrasion reaching "0.2 mm" [which presumably should read "0.2 µm"]; see paragraphs [0012] to [0014]).

5.3 The subject-matter of claim 1 of auxiliary request II is thus distinguished from the (Ti,Al)N coated tool according to E2A in that:

i) the content x of titanium in Me is: 70 at.% >= x >= 40 at.%,

ii) the content y of aluminum in said Me is: 30 at.% <= y <= 60 at.%, iii) said QI value is at least 5, and

iv) the I(200) value is at least 20 times the intensity average noise value as measured with the specified equipment (Siemens diffractometer D500) and settings.

5.3.1 The patent in suit is silent with respect to the effect of all these features.

5.3.2 The Board considers that features i) and ii) are responsible for the deposited MeX (TiAl)N compound, such as e.g. Ti0.4Al0.6N or Ti0.5Al0.5N, having the required hardness and wear resistance properties in order to be suitable as a coating for a cutting tool (compare in this context E1, page 104, second paragraph in combination with Figure 7).

Feature iii) influences the texture of the deposited MeX-compound and thereby it's cutting and wear properties.

Feature iv) is considered to be the result of the QI value since a better (more uniform) texture provides a higher peak (higher intensity) whereas the specified settings of the XRD influence the quality of the resulting diffractogram but not of the product per se. Therefore the definition of the diffractometer as such is not considered to be limiting since any equipment allowing for said settings can be used.

5.3.3 The objective problem is therefore the provision of a tool having an improved wear resistance (compare patent, paragraph [0009]).

5.4 This problem is solved by the coated abrasive as defined in claim 1 of auxiliary request II. Taking account of the examples of the patent in suit it is credible that the claimed measures provide a solution to said technical problem.

5.5 Considering the above objective problem the person skilled in the art would start from the closest prior art E2A wherein the wear resistance is improved by providing a hard coating of (Ti,Al)N having a QI value of at least 1.5 on a WC cemented carbide cutting insert. E2A teaches that lowering the bias voltage increases the QI value (see Table 1) and suggests working within the middle bias range of from 50 to 100 V (see paragraph [0007]). By lowering the bias voltage from 150 V to 80 V the QI value of the (Ti,Al)N coating is increased from 1.2 to 2.3.

Therefore in view of the Board the person skilled in the art would apply the teaching of E2A, i.e. to apply the lowest value of 50 V of said the middle range of the bias voltage. As can be deduced from the diagram annexed to the Board's communication there exists no linear increase of the QI value for (Ti,Al)N in the bias region of -50 to -60 V. On the contrary, there is a steep increase of the QI value in this region as proven by the curves based on the bias voltage and QI values of the examples 12, 8 and 5, and examples 11, 9, 1 and 6 of the patent in suit, respectively, which were all made with the compound (Ti0.5Al0.5)N at an arc current of 150A, and at nitrogen pressures of 0.5x10**(-2)mbar and 2.0x10**(-2)mbar, respectively. The line drawn between the points of the examples 9, 1 and 6 (which have QI values of 0.7, 1.5 and 15.4 at bias voltages of -100 V, -60 V and -30V, respectively) of the patent in suit intersects the bias voltage of -50 V at a QI value of about 5.

Since E2A is silent with respect to the composition of the (Ti,Al)N compound the person skilled in the art by applying his common general knowledge would select either (Ti0.4Al0.6)N or (Ti0.5Al0.5)N which have the required hardness and wear resistance in order to be suitable as the coating of the cutting tool (see E1, Figure 7).

Therefore - since the line drawn between the points of examples 1 and 7 of E2A (which have QI values of 1.2 and 2.3 at bias voltages of -150 V and -80 V, respectively) already starts well above the said line based on the points of the examples 9 and 1 of the patent in suit - the Board considers that the application of a bias voltage of -50 V in combination with the discharge current and nitrogen pressure being held constant at those of examples 1 and 7 (i.e. starting from the line of the examples 1 and 7 of E2A) would inevitably produce a QI value above 5. Therefore the person skilled in the art would inevitably arrive at the subject-matter of claim 1 of auxiliary request II without any inventive skill.

5.5.1 The appellant's arguments with respect to E2A cannot be accepted. The situation of a linear extrapolation is not given, as proven by the examples of the patent in suit. Furthermore, since E2A states that a bias voltage below 50 V cannot be used because the film will separate due to an insufficient ion bombardment (see paragraph [0009]) the person skilled in the art would conclude that the authors have carried out corresponding experiments which, however, are not described in E2A for whatever reason.

With respect to "sketch A" provided by the appellant it is remarked that no effect can be acknowledged at all since this comparison - the appellant compared the cutting distance of examples 1-2 and 4-7 (which had only a 5 µm thick TixAlyN layer on the cemented carbide substrate) with the cutting distance of examples 13-18 (which all had a first 0.4 µm TiN layer, with a second 4.6 µm thick TixAlyN layer (ex.13), or a second 4.1 µm thick TixAlyN layer with either a 0.5 µm TiCN layer (ex. 14) or a third layer of (TiAl)NO (ex.16) or a third layer of Al2O3 (ex. 17 and 18), or a second 4.4 µm thick TixAlyN layer and a third layer of 0.5 µm TiCN (ex. 15) relative to the QI value of these examples - has not been made in agreement with the established jurisprudence of the Boards of Appeal. Consequently, it has not been shown that this effect has its origin in the distinguishing feature (see Case Law of the Boards of Appeal of the European Patent Office, 5th edition 2006, chapter I.D.9.8):

Example 4 was made with TixAlyN with x=0.4 and y=0.6 while all other examples 1-2, 5-7 and 13-18 were made with x=y=0.5. Even if one ignores the slightly different composition the influence of the additional layers on the cutting distance is evident when comparing e.g. examples 1 and 13 (the latter having an additional TiN layer between the substrate and the identical TixAlyN layer having the same QI value of 1.5): 2.2 m to 4.5 m. Furthermore, as evident from examples 1-7 a higher QI value does not imply an increased cutting distance: compare example 1 (QI: 1.5 with a cutting distance of 2.2 m), example 3 (QI: 8.1 with a cutting distance of 8.8 m), example 5 (QI: 6.0 and 2.0 m), example 6 (QI: 15.4 and 4.2 m) and example 7 (QI: 22.5 and 3.3 m) which had all the same composition of x=y=0.5, and further example 4 (QI: 10.2 and 3.9 m) with the slightly different composition of x=0.4 and y=0.6 (see patent, Table 1).

5.6 Claim 1 of auxiliary request II therefore does not comply with the requirements of Article 56 EPC. Consequently, auxiliary request II is not allowable.

Main request

5.7 Since claim 1 of auxiliary request II is narrower in scope than claim 1 of the main request (compare points IX and XI) the above conclusion with respect to claim 1 of auxiliary request II applies mutatis mutandis to claim 1 of the main request.

The Board therefore concludes that claim 1 of the main request does not comply with the requirements of Article 56, either. The main request is thus also not allowable.

Auxiliary request I

5.8 Claim 1 of auxiliary request I differs from that of the main request in that a range for the stress of the MeX layer has been added (see point X, above).

The Board comes to the conclusion that the subject-matter of claim 1 of auxiliary request I does not involve an inventive step for the following reasons:

5.8.1 This feature was incorporated into claim 1 of auxiliary request I basically in order to limit the one-side open range for QI as defined in claim 1 of the main request (see letter dated 20 May 2009, point 3.2).

5.8.2 The appellant did not contest that the additional feature of claim 1 covers the normal working range for the person skilled in the art and that the stress is linked to the hardness.

The Board considers in this context that the person skilled in the art would select the optimum range of the stress of the applied coating so that it is suitable for the intended purpose of a cutting insert. Thereby the person skilled in the art would choose a stress value in the range which is common in the prior art.

5.8.3 E2A talks about this stress in terms of Vickers hardness Hv and discloses a range of 2300-3000 Hv as the normal range for a (Ti,Al)N coating and teaches to watch the compressive stress which increases with increasing bias voltage (see paragraphs [0003] and [0009]). E2A does not state that hardness is a problem but only states that the bias voltage should not go beyond 50 V since an insufficient ion bombardment is then provided, i.e. that the adhesion of the coating is not sufficient (see paragraph [0009]).

E1 similarly discloses Vickers hardness measurements for (Ti,Al)N in the range of about 2100-3000 Hv [= kg/mm**(2)] (see page 104, last paragraph; page 106, Figure 7).

D4 discloses for a (Ti50Al50)N coating on a HS steel substrate, which has been deposited at a bias voltage in the range of -50 V to -200 V with a steered arc technique, an internal stress value of 1950± 50 MPa (=1,95 GPa) (see page 548, last sentence of the first paragraph; page 548, fourth paragraph; page 550, Figure 1; page 553, second paragraph). D4 mentions generally a range of 1700-3200 Hv for (Ti,Al)N coatings (see page 551, last paragraph).

5.8.4 Consequently, none of the appellant's arguments hold because no particular effect can be seen which could be linked to this stress range.

Therefore the subject-matter of claim 1 of auxiliary request I lacks an inventive step. Auxiliary request I is thus not allowable.

Auxiliary request III

5.9 Process claim 1 of auxiliary request III differs from the reactive cathodic arc evaporation process of E2A by the following features in the characterizing portion (compare point 5.2 above):

i) realising said desired QI value to be at least 5,

ii) by increasing the partial pressure of the reactive gas, and

iii) thereby selecting the I(200) value to be at least 20 times larger than the intensity average noise value as measured with the specified equipment (Siemens diffractometer D500) and settings.

5.9.1 Feature i) influences the texture of the deposited MeX-compound and thereby it's cutting and wear properties.

Feature ii) is responsible for obtaining the desired QI value.

Feature iii) is considered to be the result of the QI value (see point 5.3.2 above).

5.9.2 Thus the objective technical problem to be solved in view of E2A is to improve the wear resistance of tools.

5.9.3 It is credible that claim 1 of auxiliary request III solves the aforementioned objective problem.

5.9.4 The Board comes, however, to the conclusion that the subject-matter of process claim 1 is obvious to the person skilled in the art.

E2A suggests lowering the bias voltage to obtain higher QI values. Thus the application of a bias voltage of -50 V in combination with the discharge current and nitrogen pressure being held constant at those of examples 1 and 7 of E2A inevitably produces a QI value above 5 (see point 5.5 above).

If the person skilled in the art wanted to get higher values then he would look to other parameters which influence the structure of the coating. D5 discloses that the preferred orientation of unbiased (TiAl)N films gradually changed from (111) to (200) as the nitrogen flow rate is increased whereas the biased films grow preferentially towards (111) planes (see page 218, summary, point 2). "Unbiased" means in this context that no bias voltage has been applied but that the so-called floating potential between the substrate and the chamber is present.

D5 thus teaches the person skilled in the art that the nitrogen pressure influences the structure and therefore he would select this parameter as another possibility to obtain a higher QI value when carrying out the cathodic arc deposition process.

5.9.5 The appellant's arguments with respect to D5 thus cannot hold. As D5 teaches either to change the bias voltage or to vary the pressure to change the (111) structure to the (200) one and since E2A only suggests varying the bias potential it is clear that the person skilled in the art would choose said second alternative, i.e. the variation of the pressure. In view of D5 the person skilled in the art would have refrained from selecting another parameter such as the discharge current or the frequency.

5.9.6 Therefore the Board considers that person skilled in the art would modify the process of E2A by increasing the nitrogen partial pressure as suggested by D5 in order to further increase the QI value and thereby would arrive at the subject-matter of claim 1 of auxiliary request III without any inventive skills.

Therefore claim 1 of auxiliary request III lacks an inventive step. Auxiliary request III is therefore not allowable.