Lead-free Machining with carbon power
The future is lead-free — at least as far as brass and copper materials are concerned. This is leading to completely different material properties and behavior during machining. The automotive industry, among others, is noticing the effects. In their search for new solutions, manufacturers are being supported by innovative companies such as Werkö, a German manufacturer of precision cutting tools, and Oerlikon Balzers.
It all began in 2013, when a new EU drinking water regulation limited the lead content in drinking water to 10 micrograms per liter. Manufacturers had to use lead-free brass in the production of sanitation products to comply with the ecological rule. As a result, one of those manufacturers, a Werkö customer, saw a dramatic increase in tool consumption when producing turned parts.
Completely altered machining
“The switch to lead-free brass resulted in four times higher tooling costs, long cycle times, tool breakage and a lot of scrap for our customer,” explains Vicente Madrid, product manager and team leader for direct sales at Werkö. The lead that had been eliminated had previously made machining and chip breaking much easier. In addition, some lead-free material substitutes increase tool wear through material smearing and produce long, winding chips, which impairs process reliability. “This changes the machining process completely,” says Vicente Madrid.
For perfect results:
Ingenious combination of tool and coating.
Manufacturers in the automotive industry also face the same problem, albeit for different reasons. In many countries, RoHS1 or similar directives restrict the use of lead in electronic equipment or components. And the ELV Directive2 2000/53/EC on end-of-life vehicles allows an exemption for copper alloys containing a maximum of 4% lead only until July 2021. This means that industries are increasingly faced with the challenge of machining lead-free or low-lead copper. At the same time, demand will grow rapidly due to e-mobility — from only 185,000 tonnes in 2017 to 1.74 million tonnes in 2027, according to one study. The reason: e-vehicles, including hybrids, require up to 3.5 times more copper than cars with combustion engines, and e-charging stations also need copper for contacts and connections.
Partnership provides a solution
After intensive testing in its own application center, Werkö developed a successful solution for its sanitation products customer. The solution is based on a special tool with a sophisticated geometry and spiraling. The coating was also tinkered with, because classic PVD coatings were unable to improve the results. But the use of BALINIT HARD CARBON from Oerlikon Balzers, a long-standing partner of Werkö, led to success on the second try. The combination of the special tool developed by Werkö with the BALINIT HARD CARBON coating solved the customer’s problem — and both tool costs and cycle times were once again within reasonable limits, as before.
This success is a confirmation for Rico Fritzsche, Segment Manager Cutting Tools at Oerlikon Balzers: “We have been gathering valuable knowledge about the machining of leadfree materials since 2014 in partnership with companies and within the research group.” And Edda Enders, commercial director of Werkö, is also satisfied, although she emphasizes: “There’s no one-size-fits-all solution for cases like this. Each need is different, and ultimately it’s small details that will determine performance.”
BALINIT HARD CARBON