Latest HMCs machine compacted graphite iron

To machine compacted graphite iron components for six cylinder diesel engines, a manufacturing system includes 18 direct-loaded horizontal machining centres providing faster chip-to-chip times.

Machining compacted graphite iron (CGI) presents a complete change to the manufacturing processes applied, said Heller Machine Tools.

The company said that significantly different tools are required for this material.

It described one of the most prestigious projects to use CGI for the manufacture of engine blocks.

Heller Machine Tools was the turnkey supplier of a production system to machine CGI components for MAN D20 6-cylinder diesel engine.

Heller has a profound understanding of transfer line and machining centre technology as well as an intimate knowledge of the automotive industry.

Heller has grown with the needs of the industry, developing its machines and services to suit the ever-changing demands of the businesses which were local to it - Daimler Chrysler, Audi and Volkswagen.

Heller supports a substantial research and development department, which concentrates on creating imaginative, effective production methods for new materials and has close associations with the universities researching materials and design for the industry.

Although Heller now supplies horizontal machining centres to a wide range of industries throughout the world, it also designs and manufacturers the MLS system.

MLS is a networked and fully integrated system composed of flexible machines linked together in an almost- infinitely variable pattern to give maximum versatility in production.

In addition, the Heller range of internal and external crankshaft milling machines completes the range for critical automotive parts.

* The project - MAN undertook the development of a new engine design based on using CGI, common- rail injection, and a state-of-the-art production system.

It chose Heller as its simultaneous engineering partner to develop a binding project blueprint.

Managing diector of Redditch, UK-based Heller Machine Tools, Geoff Lloyd, said: "The project made full use of Heller's core competences.

Experiences from numerous projects have provided Heller's engineering department with the expertise required to optimise production technology.

A wide range of solutions, incorporating everything from machining centres to dedicated machines is readily available from Heller's manufacturing programme.

The difficulties of machining CGI are readily overcome by the design and construction of all Heller machines, which provide an exceptional level of rigidity and robustness".

With Heller's project blueprint accepted, MAN selected Heller as its partner in the development and implementation of a production system for the D20 engine.

Existing facilities were to be utilized to accommodate the production system, so Heller initially modelled the layout on computer.

* Manufacturing system - the manufacturing system combines four dedicated machine lines to provide specific machining of critical features with 18 direct-loaded MCH 400 horizontal machining centres (HMC).

The HMCs have the high build quality, which provides the rigidity, robustness and precision needed for efficient and profitable production.

The HMCs provide greater productivity, faster chip to chip times, bigger axes and greater tool capacity with a reduced footprint.

As the turnkey supplier, Heller also integrated an Alfing cracking system for the crankshaft bearing caps, lift and carry systems, linear loaders and overhead gantry loaders for material handling and washing machines as well as the tooling package.

Pre-machining of the main features of the crankcase, which is manufactured from CGI 450, includes machining the cylinder head and sump face joint faces, cylinder and crankshaft bores, all of which is completed on two of the dedicated machining lines.

Single spindle machining with automatic tool changers and turret heads were used on individual stations.

The system also comprised deep hole drilling and pre-machining of the crankshaft bore.

A special feature of the system is a TBT gun drilling unit and head changer in the third dedicated machine line.

The final section in the manufacturing line is used for finished machining of numerous sealing faces, the crankshaft and cylinder bores, and the cylinder head joint face.

Within the manufacturing line machining operations are monitored via in-process gauging.

* Cylinder heads and crankshafts - in addition to developing and installing the manufacturing system for the D20 crankcases, Heller also took full responsibility for planning and commissioning the manufacturing process for the other key components of the engine.

The cylinder head is manufactured using 10 Heller MCP-H 400 HMCs and 4 HCS 400 head changers integrated into an automated line.

The latest generation of Heller's internal milling machines is employed for crankshaft machining.

The machines of the RFK 400 (300) range provide excellent quality in the machining of mains and pins.

The result of the project was "remarkable", said Heller: the D20 engine has a 25% reduction in engine components and a weight reduction of 100kg.

It meets significantly reduced emissions standards, extends maintenance intervals to 120,000km and cuts fuel consumption by more than 5%.

Lloyd said "The project has been an exciting venture for both companies, and a highly successful one.

By combining state-of-the art materials, engine design, production machines and methods a highly successful new-generation of heavy engines for commercial use has been created.

It has utilised Heller's core competences to their full advantage and is a perfect example of the way in which Heller can bring to fruition a project in a previously untried field".

* About CGI - although compacted graphite iron (CGI) has been known to metallurgists for many years, it has only recently become interesting to the automotive manufacturers.

Used for the manufacture of engine blocks and heads, compared with traditional grey cast iron it offers advantages such as more power and longer intervals between maintenance, reduced weight, less pollution and diminished noise.

However, it also presents a complete change to the manufacturing processes applied, since significantly different tools are required for this material.

* Heller at EMO 2007, Hannover, Germany, September 17-22, Hall 12, Stand C85.

* Alfing at EMO 2007, Hannover, Germany, September 17-22, Hall 12, Stand C86.

* TBT at EMO 2007, Hannover, Germany, September 17-22, Hall 2, Stand D65 and Hall 4, Stand A65.

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