Simulations used as the basis for laser hardening applications

simulatie laserharden

Integrated laser hardening offers many advantages when producing mechanical components, but generating the correct laser parameters for new materials and surface conditions is often a process of experimentation. Simulation therefore offers a solution for making this process faster and easier.

Integrated laser hardening as a technology has many advantages for producing mechanical components such as cutting tools, guide strips, gate openings, matrices and gearwheels. The lead times are substantially shortened by combining milling and local hardening into a single step, as well as avoiding expensive logistical movements. Because laser hardening is localised, which results in faster cooling speeds when compared to traditional hardening, there is no need for finishing work such as grinding and so the hardness can be maximised. This is good for the tool life. The process is also 40 per cent cheaper when compared to traditional methods and hard finishing.

However, finding the right laser parameters for new materials and surface conditions is often simply a process of experimentation. Fusion occurring on the material surface must be avoided at all costs. Solidified surface layers are admittedly extremely hard, but are also rougher and exhibit signs of tensile stress, whereas normal laser hardening processes show no change in roughness and cause heavy compression stress (> 500 MPa). Solidified surfaces therefore lower the life span of an item in comparison with properly hardened layers and require finishing such as grinding and hard milling.

Process simulation

Sirris is now able to simulate the laser hardening process in order to speed up the process of finding the parameters faster and more easily. Using a 3D CAD model, the thermal properties of the material and the surface conditions (ground, milled or blasted), it is possible to determine the temperature distribution in the material at various speeds, spot sizes and laser capacities. Based on the phase diagram of the material and therefore the known fusion temperature, it can be determined which laser parameters are suitable for hardening correctly. The depth of the hardening can also be determined, which is certainly advantageous for unique items: cutting through an item for metallurgical analysis is not always ideal.

In order to illustrate this better, we have modelled a cutting blade in the COMSOL software package.

Would you like to find out more about this case study? Read more on Techniline (in Dutch/French).

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