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Graphic element Research > Growth > Research projects > Cross-disciplinary projects > Making a cleaner cut
Graphic element Making a cleaner cut
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The cutting of metals, a key stage in many production processes, requires lubricants to reduce tool wear and dissipate generated heat. Traditional lubricants impose a high cost on manufacturers and on the environment, as the effluents are harmful. As such lubricants can affect the health of operators, regulators and insurers strictly control the whole field. The four-year LEPOCUT project deconstructed the cutting process and looked at each element to make it cheaper, better and less polluting. Participants included makers of tools, lubricants and coatings, as well as end-users and research institutes.

During a metal-cutting operation, the lubricant can account for up to 20% of the total cost, and most of it is thrown away at the end. The main driver of LEPOCUT was to develop techniques using minimal quantities of lubricant (MQL), without risking the quality of the final product.

Closer look at cutting tools

This BRITE EURAM targeted research action identified ten specific tasks. The first step for the participants was to choose the cutting tools and machine tool systems they would use in the project. Suppliers Kendu of Spain and Kennametal Hertel of Germany demonstrated some standard tools to the metalworking enterprises that would use them. These were the major German industrial group Robert Bosch, which machines aluminium parts; Ovako Steel of Sweden, part of the SKF group and a producer of precision steel parts for bearings; and Austria's Enzesfeld-Caro Metallwerke, a member of the Austria Buntmettal non-ferrous metal group, which manufactures bronze friction bearings.

During the programme, Kendu worked on improving cutting tools, choosing the materials from which they could be made in order to minimise pollution, and delivering them to the three manufacturers - which were particularly interested in tools and techniques for working on more difficult metals and alloys.

Spanish company Danobat, which specialises in machine tools, has optimised the design of lathes and machining centres to guarantee the reliability of production processes. It also helped develop dry cutting systems, using coated tools.

New lubricants or dry machining

Specialist Italian manufacturer Fuchs Lubrificanti worked on new synthetic lubricants that would be environmentally friendly, yet give good lubrication and be suitable for MQL systems. It has succeeded in developing two synthetic fluids based on esters, which were successfully tested in the laboratory and in trials by Bosch. These have since been further analysed and have the potential to replace traditional lubricants in many processes.

The key feature of dry cutting is to eliminate the need for lubricant by applying a wear-resistant coating to the tools. Drilling and turning operations on steel showed that cutting fluids could be replaced by dry machining under controlled conditions without significant reduction in tool wear life.

Both dry cutting and MQL cutting are complex processes that severely attack the coatings. However, the project co-ordinator Bodycote of the Netherlands studied this aspect of the programme - as did Spanish research organisation, Tekniker. Tekniker developed physical vapour deposition (PVD) coatings for drilling, milling and turning tools, which successfully met the requirements for the selected materials. It also investigated the possibilities of gaseous cooling media and a biodegradable neat-oil cutting fluid.

Another aspect investigated was whether cemented carbide or high-speed steel tools with suitable coatings could cut materials such as aluminium alloys, chrome steel and bronze. Here, the effect of tool pre-treatment on coating life was found to be important. A further desirable coating property is easy stripping when the tool becomes worn and has to be reground. When the best coatings had been identified, their hardness was optimised, production costs were minimised and sample tools produced for end-users to test.

Dry machining was also developed for precision operations on bronzes and sequences of aluminium parts. The method has been proven on a laboratory scale, and production tests promise early adoption by industry.

   Total machining system

The Rhine-Westphalia technical high school (WZL) at Aachen developed a systematic methodology for implementing low-pollutant cutting for all the applications studied. WZL also measured the concentration of vapours in the machining area to study the health aspects, performed cutting tests with the new products, and proposed various cutting strategies.

This work led to the development of a machining system including all the new elements in a process optimised to use the least amount of cooling lubricant to give a good result. It has the potential to increase the profitability of manufacturing for a key industrial sector, while also improving the quality of the environment in Europe.

See also
Growth programme shows new ways to sustainable development
Closer look at cutting tools
New lubricants or dry machining
Total machining system

Key data

Improving production techniques is a priority of the Innovative products, processes and organisation key action. Minimising use of lubricants for metal cutting can bring valuable economies to industry, while also reducing environmental pollution and workplace health hazards.


LEPOCUT - Developing less pollutant cutting technologies (BRPR-CT95-0107)

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