Abstract

The increase in productivity regarding metal machining is one of the main efforts in industries dealing with automotive components and air & space applications. This productivity is reached by increased cutting speeds (high speed cutting, HSC), high feed rates (high performance cutting, HPC), and overall the increase in metal removing rates (high efficient production, HEP). Especially difficult to machine materials like superalloys, high alloyed steels for turbine blades, and modern cast iron materials require high performance cutting tool systems with new approaches regarding coating, substrate material, chip geometry, and tool concept. In the following presentation this issues are targeted describing special tool and grade developments for HEP metal cutting processes. Additional new developments regarding cast iron materials with high fatigue resistance and increased machinability are highlighted as well. (...)

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The Swedish company Aerodyn specialises in the machining of blades for propelling screws. The cast skin is eliminated and the profile finished through milling. After milling the surfaces are carefully polished. In this way, since the year 2000, several projects have been realized in close cooperation with the carbide expert CERATIZIT and productivity increased.

Propelling screw in application
The propelling screw converts the energy produced by the motor into motion. The propeller blades are characterised by a hydrodynamic wing profile. The blades are designed in such a way that the water streams around them asymmetrically when they rotate. A difference of pressure is caused in or contrary to the direction of movement. A current called 'thrust' is generated and drives the vessel.

5-axis milling centres for propelling blades
Aerodyn was founded in 1989 and first produced components for the aerospace industry: this is where the company name comes from. The company is based in the Swedish Karlskoga and has 40 employees who now specialise in the machining of propelling screws. In this special field Aerodyn is one step ahead. The secret: Aerodyn was one of the first companies to utilize 5-axis machining centres for the machining of this kind of blade. Previously, they used to be ground, not milled.

Per year the Aerodyn employees machine between 500 and 700 blades and numerous other components for propulsion systems of super oil tankers, freight vessels and cruise liners. The blades, cast in bronze or stainless steel, weigh between 80 kilos and 5 tons and are shipped directly to the company which equips the vessels with them. There they are assembled as propelling screws. The cycle time of one blade at Aerodyn ranges from two to three weeks or three months, depending on its complexity and size. The propelling screw has two to seven blades. Propelling screws for ice-breaking vessels are normally made of stainless steel. 75 % of Aerodyn’s blades are made of bronze, the others of stainless steel.

Maximum quality requirements – surface quality is decisive
Aerodyn’s quality requirements are extremely high. The customers’ specifications concerning both strength and form are very precise, in fact a surface roughness of Ra 1,6 is often demanded. Furthermore the weight of the single propeller blades should not differ from each other. With a given weight of the blades of 3.8. tons the tolerance is only 6 kilos, in a very fast vessel the difference in weight must not exceed one kilo. For every order independent audits are carried out before the products are released.

Productivity increase with CERATIZIT tools
In recent years several projects in the field of cutting tools have been realized in close cooperation between the Swedish Aerodyn sales and the CERATIZIT Energy & Transport segment. The CERATIZIT inserts -M31 CTC 5235 with HyperCoat-coating have, for instance, been applied now for several months. And the results are stunning. “Applying the CTC5235 inserts we have been able to increase the cutting depth by 50% and simultaneously double tool life. I don’t think we need to go into more detail here“, says a satisfied Petri Piippo, production manager at Aerodyn.
Lars Andersson, Aerodyn managing director, on the question about the particular advantages of working together with CERATIZIT states: “Quality, service and market-adapted prices are the characteristics of CERATIZIT. We also appreciate the possibility to be able to order online via the E-TechStore at CERATIZIT.”

With its segment strategy in the business unit end-users of the cutting tool division, the carbide expert CERATIZIT is particularly successful as the company counts on segment-specific and customer-specific products as well as on tailor-made solutions. In this way the global player in the field of advanced carbide solutions also proves its competence in niche markets. International cooperation within the group plays an important role here. An international team developed a unique milling concept for the automotive industry, namely the aluminium cutter MaxiMill HPC 12.

A complete tooling concept in only six months
The starting point of the project was a meeting at an automotive customer’s in July 2003. CERATIZIT made an offer to the production manager to deliver new tools which would meet the increased requirements within only six months. An extremely ambitious deadline chosen by CERATIZIT itself. The CERATIZIT project team had an additional goal: a new flexible tooling concept should be developed which would be suitable for the majority of applications in aluminium milling for the automotive industry.

This development project brought the MaxiMill HPC12 concept into being. The idea was to develop a milling concept where the number of teeth, the form of the cutter body, the coolant, the cutting edge geometry, the rake angles and the cutting materials (CBN, PCD) could be modified.

MaxiMill HPC 12 – the properties Low cutting forces thanks to positive rake angles Reduced deformation of the components Reduced built-up edge Increased tool life Tool body made of steel Precise repeatability during insert change Very high stability and longer tool life Options: bimetallic version (steel ring and aluminium core).  High speed – high performance Reduced work piece heating Maximum productivity Optimised design of tool and insert seat Axial fine adjustment Short setting time through easy handling Fine adjustment = 0.1 mm

HPC 12 allows savings up to 30 %!
The automotive industry in particular places high demands on their tools. The processes in this field must not only be quick and stable, they also need to be highly consistent and predictable. Furthermore, in most of the cases productivity has also to be improved. In a test with an AHPC 100R12.12 milling cutter MaxiMill HPC 12 showed its abilities and its saving potential at a CERATIZIT customer's who produces gear box cases made of aluminium AS7.

Applying the HPC 12 milling cutter the CERATIZIT customer was able to reduce the machining time by 11.3 seconds (at the beginning the machining time amounted to 30.5 seconds and was reduced to 19.2 seconds thanks to MaxiMill HPC 12). A surface quality of Rmax < 6µ – was requested, and CERATIZIT even obtained 4.42µ. The test is also very significant for its extreme cutting data:

• vc = 4,712 m /min
• n  = 15,000 rev./min
• f   = 25,200 mm/min
• fz = 0.14mm

These excellent results can be attained with the HPC 12 milling cutter thanks to its stability and its simple and precise fine adjustment.

International cooperation – voices of the CERATIZIT group:
The idea and the drawing for the HPC 12 concept come from France. The project was finally concentrated at the automotive segment at CERATIZIT Reutte, Austria. Jürgen Duwe from the development department in the BU end-users: “It was one of the first projects where employees of several sites were involved. Despite different languages and cultures the project was a resounding success. We got to know each other better and are now in closer contact. This will definitely be an advantage for future projects.”

“I consider the tooling system HPC 12 a real ‘door opener’ for companies of the automotive industry,” says Tinus Zuetenhorst, sales manager of CERATIZIT Nederland. “Ever since we presented this tool we have had a much stronger presence and actively invited to carry out tests. We have already been successful at three companies with the tool – this looks very promising!”

Gonzalo Artaega, sales representative at CERATIZIT Ibérica about the HPC milling system: “This solution has enabled us to offer our customer Fasa Renault Valladolid an efficient and economic tool which is better than the competitors’ tools. Above all, the low weight, the long tool life and the good surface quality produced by this milling cutter have convinced our customers.”

CERATIZIT has developed a new tooling system for special face milling operations. The MaxiMill HFC (High Feed Cutting) system is synonymous with maximum feed and chip removal rates.

High-feed cutting tools are applied where maximum chip removal rates must be achieved in a minimum of time. A typical application is rough milling of flat faces, for instance in the field of mould and die construction.

MaxiMill HFC guarantees minimum vibration thanks to a light cutting geometry with positive rake angles and high chip removal rates. The inserts for this system have a special chip groove specifically developed for this application and are offered with the innovative HyperCoat coatings. CTP1235 (for steel), CTP2235 (for stainless steel) and CTC3215 (for cast iron). The combination of the new HFC milling system and the latest CERATIZIT grades guarantee maximum performance in terms of tool life, surface quality and reduced tendency for vibration.

The optimised tool coating ‘hard & tough’, which is both wear resistant (hard) and corrosion resistant (tough), guarantees long tool life. 

Flexibility concerning the coolant plays an important role when high-feed milling. Every tool therefore possesses a special coolant hole design which is particularly adapted for minimum quantity lubrication.

The main application range of the new MaxiMill HFC system is face milling with maximum feed (up to 3.0 mm per tooth), plunging for the production of deep pockets and with maximum chip removal rates (more than 1,500 ccm/minute).

AUDI HUNGARIA MOTOR Kft. in Györ, Hungary, has 5,500 employees. Here the engines for the brands of the Volkswagen group, Audi, VW, Skoda and Seat are manufactured. In Györ the Audi TT Coupé and Roadster is built, and the Audi A3 Cabriolets will be built there in the future. In 2006 more than 23,500 vehicles and close to two million engines left the plant. This makes Audi Hungaria the second biggest exporter in Hungary. For the machining of crankshafts Audi Hungaria counts on the technology and experience of the carbide expert CERATIZIT.

Audi is synonymous with optimum technical performance and the logo with the four rings. In a few words: Audi ranks as one of the top firms in the automotive world. It therefore makes sense to purchase products at CERATIZIT, the technological leader in the field of carbide for wear parts and cutting tools.

Crankshaft machining at Audi
Györ is situated 45 km from the Austrian border, in Hungary, and numbers 130,000 inhabitants. Since 1994 Audi Hungaria Motor Kft has been located at the periphery of the town. Audi selected this site for various reasons: the logistic connection is very good, within a radius of 50 km there are competitive subcontractors, a hall with a surface of 100,000 sq.m. already existed, and a lot of people in this area speak German very well. Furthermore the technical University of Györ ensures that well-trained engineers and experts are available.

Crankshafts are exposed to enormous forces; their production requires maximum precisionZoltán Szathmári is in charge of production planning and tool technology in engine production at Audi Hungaria Motor Kft. He works closely together with the CERATIZIT representatives and development specialists. His most important contact on site is Barnabás Deri, the sales manager of CERATIZIT Hungaria.

Szathmári leads us through the impressive production department: high, luminous halls with three extremely long and up-to-the-minute production lines, which are in addition fully automated. At Audi in Hungary it is very clean and one is immediately aware that the employees are proud to work here.

In crankshaft machining Audi Hungaria relies on seven different types of inserts from CERATIZIT: special solutions CERATIZIT developed together with the machine manufacturer GFM. Maximum precision is required. Zoltán Szathmári explains: “The crankshaft is an essential component of the engine. It converts the linear movement into a rotational movement. The component is exposed to enormous forces. We manufacture six different crankshafts. The crankshafts are supplied in forged condition. Before machining, a crankshaft for the 3.0 TDI engine weighs 26 kg, after machining it still weighs as much as 18 kg.“

Interview with Zoltán Szathmári, production planning and tooling technology at Audi Hungaria

Mr Szathmári, what is important in the machining of crankshafts?
Szathmári: “Two thirds of production relate to the 3.0 TDI engine. The crankshafts for this engine are made of 42CrMoS4. Rough machining of this crankshaft represents a difficult task as it consists of a high-tensile material at the limit to soft machining. The hard forging skin virtually ‘eats away’ the tool.”

What does that mean for the tools?
Szathmári: “The blank crankshaft is irregular and shows varying properties and the surface is not homogeneous. This means hard and irregular strain on the insert.”

How long does an insert last?Szathmári:“When rough machining (rough milling of main bearing and webs) the inserts are mounted on a planetary milling cutter or side and face milling cutter. After around 250 crankshafts the inserts in the milling cutter have to be indexed.”

How do you assess the relationship with CERATIZIT?
Szathmári: “We have been working together with CERATIZIT for four years and maintain a very open relationship, there are no secrets. For every new development we are informed precisely about what has been improved. CERATIZIT is in a continuous optimization process and is aware that coming to a standstill is dangerous, because the pressure is high: every year we invite tenders for the inserts, every year there are new test procedures and CERATIZIT has to assert itself. We have been very successful for four years.”

Interview with László Janó, product segment V6, mechanical production department at Audi Hungaria

Mr Janó, how long does the machining of a crankshaft take?
Janó: “There are several ways of looking at this. You could say that at the end of the production line a finished crankshaft comes out every 49 seconds. This is the cycle time of the line. Including the buffers (per line there are 5,700 cranks in the buffers) the flow time for 1,400 parts per day amounts to around six days.”

How important is the role of the tools in this production line?
Janó: “Extremely important. This line is very complex and flexible. The investment for such a line, for instance, is three times as high as for a line for the production of cylinder heads. For such a complex machining method process security has to be very good. In the automated machining chain tool life has to be consistently high. 65% of the costs are tooling costs. The tools also play a very important role."

What is the proportion of non conforming material?
Janó: “The tolerances for a crankshaft are very close. The entire line is designed for this and is continuously optimized. Quality control is also very intensive. For the 3.0 TDI engine a 100% rupture test is carried out. For me the quality of the final product is important, not so much the share of non conforming material. In the last four years only two crankshafts have been returned to us; this was due to faulty material, not to faulty machining.“

What can a crankshaft withstand?
Janó: “I don't want to give numbers, but the basic rule is that the crankshaft has to withstand three times as much as the engine."

[Technical info box] Patrick Zobl, product manager at CERATIZIT, describes crankshaft machining in detail Technique for crankshaft machining High cutting speeds (up to 260 m/min) Planetary milling cutters with diameters ranging from 350mm to 750mm  Dry machining leading to high temperature stress on the cutting material.  High number of teeth of the planetary milling cutters (40 up to 200 teeth) Main bearing and webs are machined at the same time with two planetary milling cutters Due to the length and the relatively small diameter of the crankshaft machining stability is low Requirements with regard to the CERATIZIT inserts High resistance to thermal shock Consistent quality of the cutting material providing process security at the customer Long tool life, therefore low tool changing costs Smooth surface thanks to lower frictional heat and wear Materials used in crankshafts Cast iron materials for engines when subject to reduced stress in the engine Alloyed steel (Cr, Ni, Mo) with high fatigue strength in engines which are subject to higher stress or to reduce weight Basic characteristics of CERATIZIT inserts Geometry of the insert is mainly defined by the profile of the crankshaft CERATIZIT chooses the insert to be applied as well as the geometry of the cutting edge

[Info box about the production steps] Steps in the production of a crankshaft a. Preparation Cutting and centring Internal and external profile milling of the pin of the bearing and connection rod bearing pin Turning of the main bearing pins and the end parts Deburring Solid carbide deep hole drilling b. Hardening (induction hardening) c. Finishing Hard turning Threading Chain wheel broaching CBN grinding Fluorescent rupture test Dynamic balancing Finishing (polishing and lapping) d. Quality test

“Now it is important to find one’s own way to follow in the footsteps of a great predecessor.” This is how Andreas Olthoff, new managing director of the CERATIZIT Deutschland GmbH, sees his task. At the beginning of August he followed Jan van der Veen who retired after fifteen years at CERATIZIT.

“I believe that a company cannot be successful without team spirit“, says Andreas Olthoff, new head of CERATIZIT Deutschland GmbH. He sees his style of management as ‘result-oriented’ while allowing employees a good deal of individual responsibility.
 
A rapid career
The new managing director (age 41) has already gathered experience at the German branch of an American company. He began his career in the field of sales there after studying mechanical and economic engineering. He became key-account manager for northern Europe, subsequently sales manager and was then appointed managing director.
“After fifteen years I was looking for a new professional challenge,“ he states. At CERATIZIT Germany he accepted this challenge. The sales volume of the CERATIZIT group in Germany is >100 million Euros; the sales company employs 65 people. The new managing director says: “I’m happy to have found a growing company with an excellent international position. It is a gratifying and challenging task to contribute to the further success of CERATIZIT.“
 
Commitment to the Corporate Values
Andreas Olthoff considers Corporate Values an overall concept with important functions. He thinks that the value of communication and an interaction based on trust between superior and team are essential for a continuously growing company. “No company can be successful without the active implementation and experiencing of values,” he says. “I would like make a contribution to this company culture.”His predecessor Jan van der Veen supports this belief: “I have often regretted that we talk a lot about our corporate values but do not always live according to them. Communication matters, trust and respect matter!“ So the change of generations at the vanguard of the CERATIZIT Deutschland GmbH is all settled.
 
Short description of Andreas Olthoff
Age 41, married
Hobbies: running (marathon), squash, motor-biking
Studies: mechanical and economic engineering
Professional career:
15 years in the German branch of an American company (listed on the stock market) selling hydraulic tools. His positions were
- Junior sales representative
- Key-account manager for northern Europe
- Sales manager
- Managing Director
.

The launch of CERATIZIT’s MaxiMill HEC face milling system at EMO 2007 is further proof of the high levels of research and development taking place at its Reutte, Austria manufacturing facility.

The MaxiMill HEC accepts CERATIZIT precision-manufactured inserts of either carbide, ceramic or CBN material, which provide up to eight useable edges. These tangentially-mounted inserts are mounted in such a way as to ensure maximum cutting performance and cutter stability, while at the same time reducing the power required to operate them at their optimum, making them suitable to a much wider range of machine tools.

The result is a face milling cutter that will generate high table feeds, long and consistent tool life, economic application and process security. While MaxiMill HEC can be used in virtually any C.I. face milling application it will be of real interest to those companies supplying the automotive sector where the volumes and component types will suit its particular characteristics and generate the maximum productivity and cost savings for the end-user. Typical application areas for MaxiMill HEC would be cast iron components such as contact faces of crank cases, cylinder heads, turbochargers and pump cases, etc.

“MaxiMill HEC is the result of an ongoing and extensive development programme at CERATIZIT”, says Conan Jackson, CERATIZIT UK’s Sales Manager. “HEC is a welcome extension to the existing MaxiMill range and will provide many of our automotive customers with the opportunity to maximise their machine capacity while reducing tooling costs.”

With the LNHX 1106PNER inserts available in grades CTC3215 (carbide), CTN3105 Si3N4 (ceramic) and segmented CBN, the cutting data achieved is impressive. For example, machining GG25 material at a hardness of HB 180-220 is achieved at 200m/min, 0.25 mm/tooth feed rate with up to 5 mm depth of cut and 79 mm width of cut. Similarly, GGG 70 material at a hardness of HB 240-300 can be cut at 180 m/min at a feed of 0.2 mm/tooth.

What do the punctual departure of a train, a tenancy agreement, a game of chess and New Year’s Eve have in common? They are all subject to time. A contribution on the ‘time on the wrist’, the innovative watch manufacturer Rado and CERATIZIT’s role in the production of scratchproof watch cases.

The presentation of the first scratchproof watch in 1962 represented the start of Rado’s success story. Everything began when Rado chief designer at the time, Marc Lederrey, put forward a totally new idea. He was constantly irritated when gold and steel watches, which at the beginning looked beautiful, often showed scratches after only a few days and subsequently had to be polished frequently. Then, tungsten and titanium carbides were only known as extremely resistant materials in the field of high-tech production of special tools. “Making a watch out of this material - that would be the solution," said Lederrey. And Dr. Paul Lüthi, who was at that time the boss of Rado, gave the go-ahead for this development. The result: the first scratchproof watch in the world!

High-tech materials in watch production
Today Rado is one of the most important watch manufacturers in Switzerland. The Rado group has been part of the Swatch group since 1983 and already has more than 300 service centres and more than 8,000 sales points.

While other watch manufacturers apply conventional materials such as gold, copper or steel, Rado counts on high-tech materials of the future. Lanthanum, ceramic, sapphire crystal, high-tech diamond and last but not least carbide. The level of scratch resistance of a material depends on its hardness. Hard materials make scratches in softer materials: diamond makes scratches in sapphire, sapphire in glass, and glass in metal. The harder a material, the more brittle it is, and thus more sensitive to impact. Resistance to scratches therefore is not the same as indestructibility.

Rado has never only focused on beautiful watches. The main decision has always been the selection of the material. In this way design and material combinations are developed which perfectly combine the two functions of a watch:  a modern piece of jewellery and a functional time indicator.

Carbide from CERATIZIT for the top watch brand Rado
CERATIZIT has supplied Rado with carbide cases for decades. The development and the production of the cases started at the beginning of the 1960's at the Reutte site. Now they are produced in Mamer, Luxembourg and are then subjected to several machining processes at Rado’s subcontractors until they become high-quality watches. Marc Lanners, production manager of the watch case line in Mamer: “The most tricky thing when producing watch cases is aesthetic quality. The preparation of the feedstock (a mixture of powder and binder) is of maximum importance in order to be able to fulfil the quality requirements. Both surface and form have to be absolutely perfect. This is why quality control is obviously extremely important for these products. We have very precise control systems.”

“We produce tens of thousands of carbide watch cases per year, today we have five models,” says Hans Müller, business segment manager of special industrial wear parts. “Even for these high-quality products the life cycle is continuously decreasing. We must therefore react ever faster. The latest case model was developed within only four months by CERATIZIT.”

Interview with Peter Oppliger, Rado Purchasing Manager

How did the partnership with CERATIZIT start?
Oppliger: The partnership began in the middle of the 1980’s. After carrying out a detailed study about batch production of our model ’The Original’ whose success has been unparalleled since 1962, we decided to modify our production method. We no longer wanted to produce the watch crown of our top model through pressing but through injection moulding. So we referred to Cerametal in Luxembourg.

Why does Rado count on carbide from CERATIZIT?
Oppliger: CERATIZIT has a reputation as a reliable business partner. Its extensive know-how in the field of carbide injection moulding enables embossing of our logo in the watch case. In this way it’s also easier for us to proceed against counterfeits.

What is important with regard to the watch cases? What are the special characteristics and properties?
Oppliger: Since its foundation 50 years ago Rado has always been a watch manufacturer who has focused specifically on technology and innovative batch production processes. At the time of the market launch the objective was to create a watch on which time would leave no traces, i.e. a scratchproof watch. For this purpose you need a hard and sufficiently shockproof material. Carbide combines these characteristics and in addition is a visually pleasing material, which is extremely important for watches.

What are the current projects and further developments?
Oppliger: Following its pioneering spirit Rado is working on several projects simultaneously; however, we are unable to discuss anything particular about them right now. CERATIZIT has offered us a very interesting new carbide which is light and hardly releases any nickel. So it can continuously be in contact with the skin. This new material allows us to think about many possible applications for the future.

Are there any materials which compete with carbide?
Oppliger: In a certain respect high-tech ceramic manufacture which was introduced in the watch industry by Rado, is a carbide competitor. Its lightness and hypoallergenic properties make this ceramic a material which can be easily worn on the wrist without complications.

What would CERATIZIT have to optimise in order to score additional points and to get more business?
Oppliger: As for every other supplier for us it seems important to maintain close cooperation and good communication. As these are luxury articles where aesthetics and quality are basic requirements it is obviously decisive to guarantee consistent and impeccable quality.

The Rado Story

• In 1917 in Lengnau (canton of Bern, Switzerland) the watch producer Schlup & Co. was founded by the Schlup brothers. Later on, this subcontractor for the watch industry becomes Rado Uhren Co. Ltd.
• In 1957 the first watch collection is presented under the brand name Rado.
• Today the Rado products are available all over the world in 180 countries. 
• The brand has about 8,000 sales points and more than 300 service centres.
• Rado has around 300 employees.