Kennametal Inc. v Pramet Tools Sro and Another
| Jurisdiction | England & Wales |
| Judge | Henry Carr |
| Judgment Date | 05 March 2014 |
| Neutral Citation | [2014] EWHC 565 (Pat) |
| Court | Chancery Division (Patents Court) |
| Date | 05 March 2014 |
| Docket Number | Case No: HC12B01709 |
[2014] EWHC 565 (Pat)
IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT
Royal Courts of Justice, Rolls Building
Fetter Lane, London, EC4A 1NL
Henry Carr QC
(Sitting as a Deputy Judge of the High Court)
Case No: HC12B01709
Alastair Wilson QC & Richard Davis, instructed by Browne Jacobson, for the Claimants
Iain Purvis QC & Kathryn Pickard instructed by Charles Russell LLP for the Defendants
Hearing dates: 28, 29, 30 January and 3 February 2014
Approved Judgment
I direct that pursuant to CPR PD 39A para 6.1 no official shorthand note shall be taken of this Judgment and that copies of this version as handed down may be treated as authentic.
Contents
| Introduction | 3 |
| The expert witnesses | 5 |
| Mr Palmer | 5 |
| M. Festeau | 6 |
| Professor Axinte | 6 |
| Common general knowledge | 7 |
| Milling tools | 7 |
| Indexable cutting inserts | 7 |
| Positively-held cutting inserts | 7 |
| Face milling | 8 |
| Surface quality | 8 |
| The 643 Patent | 9 |
| Claim 1 of the 643 Patent | 10 |
| Construction | 11 |
| Substantially straight cutting edge region (integer 15) | 11 |
| Secondary conical clearance surface (integer 14) | 13 |
| Infringement | 14 |
| The consequences of my construction of Claim 1 | 14 |
| Is there a substantially straight cutting edge region of 0.2mm in the Pramet inserts? | 14 |
| The Defendants' design drawings | 14 |
| The Wendt grinding machine | 15 |
| Slope functionality | 15 |
| Mr Palmer's experiments | 16 |
| Shadowgraph | 16 |
| Original CMM results | 16 |
| The Zoller tests | 16 |
| Mr Palmer's milling tests | 16 |
| Professor Axinte's experiments | 17 |
| The microscopic photographs of the workpieces | 17 |
| The CMM tests carried out by NPL | 17 |
| The surface texture scans | 18 |
| Conclusion in relation to the alleged substantially straight region of 0.2mm | 19 |
| Infringement – secondary conical clearance surface | 19 |
| Additional defences to infringement | 20 |
| Section 60 (2) — "when he knows or it is obvious to a reasonable person in the circumstances" | 20 |
| No supply of ZDCW inserts | 22 |
| Validity | 23 |
| Squeeze between construction and infringement | 23 |
| Free standing invalidity case | 25 |
| Figure 21 of Nagashima | 25 |
| Figures 7 and 8 of Nagashima | 27 |
| Other matters | 28 |
Introduction
By this Claim, the Claimant alleges infringement of EP (UK) No. 1,897,643 ("the 643 Patent") for a " milling cutter tool for high feed face milling". In particular it alleges that cutting inserts produced and sold by the Defendants ("the Pramet inserts") are infringements pursuant to Section 60(2) of the Patents Act 1977. The Defendants deny infringement and counterclaim that the 643 Patent is invalid in the light of two prior publications: Japanese Patent No. 52–103081 ("Dijet") and European Patent Application No. 1,260,298 ("Nagashimi").
Cutting inserts are held in revolving cutter bodies and are used to remove metal from workpieces, particularly in milling operations. Figure 8 in the 643 Patent(the first part of which is reproduced below) is an enlargement of one pocket of a cutter body (41) with a cutting insert in the bottom right hand corner.
Figure 8:
Mr Alastair Wilson QC, who appeared for the Claimant, explained the operation of the cutting tool as follows. In use, the cutter body will revolve about an axis running from top to bottom of the figure and will advance towards the right of the figure. The advance rate is measured in mm. per tooth. Considering Figure 8, it can be visualised that the individual insert is driven down into the page and cuts into the workpiece at a rate defined by the product of the cutting speed, " depth of cut" and the advance rate per tooth. The inserts will in due course traverse the page in the opposite direction on the other side of the cutter as they revolve round towards the front.
Before the priority date of the 643 Patent it was well known that cutting inserts were liable to carve a pattern of V-shaped grooves and ridges into the milled surface, which would not produce a good surface finish. The cutting inserts were then liable to traverse these ridges and the back side of the cutter body would cut chunks out of them, making the surface finish still worse. When the primary milling process had finished the surface finish would need to be improved by a finishing step to smooth out the surface. Regions of cutting inserts, which performed this finishing step, were well known at the priority date and were called " wipers".
One feature of the characterising portion of claim 1 of the 643 Patent is a " substantially straight cutting edge region of the cutting insert" which is required to extend " in a direction substantially perpendicular a cutting axis (46) of the cutter body". The parties referred to this feature as "a substantially straight region". The substantially straight region is shown at 29 in the second part of Figure 8 in the 643 Patent, which is reproduced below.
Figure 8:
The substantially straight region is said at paragraph [0034] of the 643 Patent " to guarantee good surface finish on the machined surface".
A primary issue between the parties is whether the Pramet inserts contain a substantially straight region. This has prompted a total of seven sets of experiments, all aimed at determining the presence or absence of a substantially straight region. This is because there is no substantially straight cutting edge region in the design drawings of the Pramet inserts. Furthermore no such region can be seen with the naked eye or under magnification. I consider this issue further below.
The Parties
The Claimant is the proprietor of the 643 Patent, having purchased the relevant part of the business conducted by the previous Claimant, TDY Industries LLC ("TDY"), including the 643 Patent and all rights arising in respect of infringement. Kennametal Inc. was substituted as Claimant for TDY by an Order dated 22 January 2014. The First Defendant is a Czech company that designs, manufactures and sells cutting tools, including inserts for use in such tools. The Second Defendant is the authorised distributor of the First Defendant's products in the UK. It offers certain of the First Defendant's inserts for sale via its website and has in the past offered them in catalogues.
The alleged infringements
There are two types of Pramet inserts in issue: the ZDEW120408 and the ZDCW09T304 inserts. I will refer to these individually as the ZDEW and ZDCW inserts.
The skilled addressee of the 643 Patent
There was very little between the experts as to the identity of the skilled person. He or she is a person (or team) with responsibility for designing and manufacturing metal cutting tools and their inserts.
The expert witnesses
Mr Palmer
The CMC order of Morgan J. dated 5 th December 2012 allowed both sides to call one expert witness. The Claimant's designated expert was John Palmer. He is an employee of Stellram, a company that was taken over by TDY and acquired by the Claimant. He is Stellram's " Global Aerospace Segment Manager". During cross-examination, Mr Palmer explained that he was in charge of one of the largest sectors of the Claimant's business (aerospace comprises about 40% of the business). He also explained that the inserts protected by the 643 Patent are " of great importance to that business."
Mr Iain Purvis QC on behalf of the Defendants suggested that this created an obvious conflict of interest for Mr Palmer between the requirement, as an expert, to remain impartial and uninfluenced by the pressures of litigation, and his duty as a senior employee of the Claimant to promote its interests. Mr Purvis illustrated this by reference to various passages of Mr Palmer's cross-examination. For example:
"Q. Obviously, therefore, you are very keen that your company should win this case.
A. Yes, I would say so" [T/2/226 lines 22–24]
He was also asked how he was able to maintain independence given his position within the Claimant and the importance of the 643 Patent to the business of which he was in charge:
"Q. So I am right, that it is hard to imagine anyone less independent than you as an expert in this case.
A. In the way you put it, yes."
In my judgment Mr Palmer was put in a very difficult position in his role as an independent expert. He was not an obstructive witness. However it became clear during his cross-examination that he considered that his task was to find a substantially straight region in the Pramet inserts and that it was important to maintain this view even where it was difficult to support with objective reasons. This does not mean that I disregard his evidence. I consider that he has great practical experience of cutting inserts and was at times able to assist the Court. However, this lack of objectivity is something that I bear in mind when considering his evidence.
M. Festeau
M. Festeau was one of the named inventors of the 643 Patent and is employed by the Stellram division of the Claimant. He gave evidence of fact at the trial relating to the circumstances in which the invention was made. However at the start of the trial a third witness statement of M. Festeau was served which purported to comment on the Defendants' second Notice of Experiments served on the 15 th January 2014. This statement was only admissible as expert evidence. The Defendants did not object to its admissibility and therefore M. Festeau was permitted to give evidence as a second expert.
The Defendants submitted that M. Festeau lacked independence, being one of the inventors of the 643 Patent as well as an employee of the Claimant. They further submitted that there had been...
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