The article below appeared on page 28 of the November/December 2009 issue of European Tool & Mould Making magazine.
Innovative Coating Methods for Moulds and Dies Produce Optimized Surfaces Cost-Effectively
Industry Trends: Developments in Technology
Coatings applied to moulds and dies by means of physical-vapour-deposition (PVD) techniques provide these tools with many performance advantages. Mainly, they add extra hardness and smoothness to a forming tool, which extends its life span as well as enhancing its performance. As an expert in PVD technology and equipment, the Dutch company Hauzer Techno Coating B.V. supplies several innovative mould-coating system technologies.
HIPIMS+ is a sputter technology for producing dense and defect-free coatings, PVD-deposited aluminium oxide coatings create mould surfaces with outstanding nonsticking performance, and the Nitrocoat Duplex Treatment provides plasma-nitriding and physical vapour deposition in just a single process step.
HIPIMS+ Technology
Not only is optimum hardness required in forming tools, but a smooth tool surface is equally important. The classic deposition methods in PVD coating technology arc evaporation and sputtering, both of which have their disadvantages. The arc technology that is employed in the evaporation method necessitates extra process steps for polishing, while, with sputtering, the deposition rate is low and the coating may be less dense than is ideal, risking adhesion problems.
High-power impulse magnetron sputtering (HIPIMS+) technology is attracting ever greater interest from the market because it enables an atomically smooth, dense coating to be deposited. This technique’s deposition rate is much faster than that possible with a traditional sputtering process. Hauzer has conducted tests with HIPIMS+ for AlTiN and Cr2N coatings and achieved excellent results.
PVD-Deposited Al2O3
Aluminium oxide coatings deposited via PVD technology have been around for a few years, with new process developments continually improving the coatings in this class. Aluminium oxide is well known for its antistick features, which make it suitable for applications involving injection moulding of aluminium or magnesium.
Normally, aluminium oxide is deposited as a coating via high-temperature chemical vapour deposition (CVD). But the improved PVD coating process works at much lower temperatures and produces a surface exhibiting high toughness. Coating layer thickness has been improved as well; layers as thick as 5 µm are easily achievable.
Nitrocoat Duplex Treatment
Plasma-nitriding is a well-established process for hardening the surface of dies and moulds. Hauzer Techno Coating has developed this process in tandem with PVD coating to create a one-step dual process called the Nitrocoat Duplex Treatment. In this process, the nitride forms a layer graded toward the hard PVD top layer. A prominent job coater has used Nitrocoat Duplex Treatment for some time now, particularly on cold-forming tools, and has found the results in terms of process stability, surface hardness and compound layer to significantly exceed those attainable via conventional plasma-nitriding.
The distinctive feature of the nitriding process, formation of a white layer, is absent in the Nitrocoat Duplex Treatment. This leads to much better adhesion of the PVD coating. Furthermore, the time necessary to achieve an effective case depth of 0.1 mm is considerably less than with conventional plasma-nitriding.
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Company Information
Hauzer Techno Coating BVP.O.Box 3057
5902 RB Venlo, Netherlands
+31 77 355 9777
Fax +31 77 3969798
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