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
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
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
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
or dry machining
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
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
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
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.
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.
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.
- Developing less pollutant cutting technologies (BRPR-CT95-0107)