Functional surfaces are a key factor for the quality, efficiency and competitiveness of products and processes that are subject to complex strains and stresses. Tailor-made materials and procedures ensure resistance to abrasion, erosion and corrosion – the very factors that influence the service life and life cycle of plants and equipment.
As a generative process with reliable reproducibility, precision 2D or 3D application capability and low levels of strain on the treated components, laser cladding is the established standard for the specific adaptation of surface properties to the requirements of their specific fields of application in mould construction, tool making and mechanical engineering. But this procedure using standard processing heads meets its limits when it comes to difficult-to-access internal contours.
Proven solution
Access apertures of less than 100 mm call for considerably slimmer optical heads. This is where the iClad comes in, a compact special laser head with integrated process media feed developed by Pallas GmbH & Co. KG in Würselen near Aachen, Germany. This solution, which has already proven itself repeatedly on a project basis, makes laser cladding of internal contours and blind bores possible to a working depth of 500 mm through access apertures down to the size of a two-euro coin. Now, the strategic partnership between Pallas and the German company GTV Verschleißschutz GmbH in Luckenbach (Westerwald) marks the starting signal for industrial serial production and worldwide marketing of the iClad.
In laser cladding, the strictly localised laser beam melts the base material of the workpiece and the powder feed and joins them metallurgically into a dense coating with low dilution. This approach, controlled by CAD, makes coating thickness ranging from a few tenths of a millimeter up to several millimeters possible. Thanks to the tight focusing of the laser beam, the thermal strain on the component and its base material is very low, which keeps warpage to a minimum. The near-net coating also minimises the need for reworking.
Compact casing
All necessary assemblies for beam guidance and formation are integrated in the compact casing. The plugs for laser fiber and feed lines for the process media are located at the rear end of the head. An active cooling system protects the optical components from overheating, and an internal lens protection prevents deposits of powder particles building up. The optical path is constantly flushed with shielding gas, and an optional camera connection supports calibration or monitoring of the process.
With a working depth of 500 mm through access apertures from as small as 30 mm diameter, iClad is ideal for repairing transmission components, housings, cylinder liners or tools. In the coating process, the rotationally symmetrical workpiece is rotated around the fixed processing head, which, depending on the positioning of the treatment area, may employ one of two different laser beam angles. Blind bores, where the laser beam's working point is in front of the head, are treated using a 30° beam angle; through bores with a 90° beam angle. In contrast to conventional processing heads, where working distances of 20 mm are common practice, the iClad® only needs a working distance of 5 to 12 mm.
Bundling strengths
Through the partnership between Pallas and GTV, the aim is to advance customer-geared further development of the special laser processing head, and to make it increasingly available on the market. Pallas will continue to be in charge of development, design and production of the processing heads, especially in the case of custom constructions. GTV will assume responsibility not only for global sales and distribution, but also for development and optimisation of individual components like nozzles.
A first special processing head with a nozzle construction by GTV/Pallas is currently in use in continuous three-shift operation and impressing users with its improved powder feed and increased level of efficiency. For global marketing of the iClad, GTV's strategy is standardisation of the system components to render the device suitable for serial production. This will ensure that large companies will find the same conditions for deployment of the processing head for laser cladding everywhere, regardless of location. Service and support will be provided through GTV's international sales partners and subsidiaries.
