Ceramic coating layer ideal for milling processes

LMT

Nanolock Black layer

LMT's Boehlerit division has launched Nanolock Black, a heat- and wear-resistant ceramic coating layer that helps to withstand the impact stresses created by high-productivity milling processes.

Nanolock Black is designed to maximise performance and insert tool life when milling without coolant.

The new coating also provides high protection against wear and extends the in-cut life of the insert thanks to its elastic damping effect.

Nanolock Black milling inserts, now available through LMT UK of Meriden, capitalise on LMT's expertise in chemical vapour deposition (CVD) to deposit the Kappa-A1203 ceramic layer to the titanium carbonitride (TiCN) coating.

Thanks to the 'zip-fastener' bonding of the nano-structure, the effects of abrasion on the insert are minimal and any tendency for 'thermal comb' cracks to develop are resisted.

The new coating also means that any surface oxidation is prevented when used in dry milling applications.

The introductory Universal Nanolock LC230E milling insert was initially applied to demanding applications such as machining the edges of steel plates for pipelines and resurfacing manganese-steel railway lines, where the black coating has been run at cutting speeds of up to 300m/min.

Central to Nanolock's performance capability is the ultra-fine needle-shaped surface adhesion characteristics achieved through the development of its coating technology that was originally pioneered by LMT's Boehlerit division and launched some two years ago on the LMT Steeltec LC215K turning insert.

The company was able to work at nanostructure levels (1nm = 1 billionth of a metre), which enabled a reduction in the crystallite size of particles.

In addition, by mixing the elements of carbon and nitrogen used in TiCN coatings, it was able to improve the bonding of the different material particles.

Last year, LMT created Nanosphere Red, a nano-composite multi-layer coating of titanium, aluminium and nitrogen (TiAlSiN) for milling hardened materials and high tensile steels up to 68 HRC.

Nanosphere Red has the capability to be worked at temperatures some 200C higher than existing aluminium-nitride coatings, which typically cannot exceed 850C.

The coating is also said to improve the working life of LMT's inserts.

Since the original launch of the Steeltec LC215K indexable insert for turning, LMT's application engineers have demonstrated the advantages of the extreme levels of hardness without brittleness achieved with Nanolock coatings when machining steel at more than 300m/min.

Even when running at these high cutting speeds, the applications have still recorded improvements of more than 50 per cent in the effective cutting life of the insert.

The Nanolock Black coating is now available in a range of ISO indexable milling inserts and is acceptable on all common tool systems.

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