A novel strategy for the production of sintered ceramic dental implants is reported. The innovative and versatile 7-axes laser processing test bench makes the production of complex shapes with high precision possible. Quasitangential strategies prove an average deviation smaller 5 μm with a surface roughness Ra of 0.24 μm. The material is an yttria-stabilized alumina-toughened zirconia ceramic suited for biological applications subjected to load and wear. The heat-affected zone is negligible as shown by Raman spectroscopy. Following, this layer is laser ablated with an orthogonal strategy. Defined surface structures, like spots and grooves in the micrometer regime, are introduced for potential altered tissue interaction and enhanced osseointegration.
A novel conditioning routine of metallic bonded diamond grinding worms is reported. The competitive manufacturing time is realized by a combination of orthogonal and quasi-tangential laser processes. The introduced quasi-tangential process is only limited by the maximum available laser power of 100W at 10 ps and 800 kHz for roughing. Hence, a maximal ablation rate of 55mm3 min-1 is reported and the accumulated ablation rate for conditioning is 3mm3 min-1. Following, the manufacturing of grinding tools within a maximal geometric deviation of 40 μm is shown. The threaded tool is finished by a laser sharpening process exposing the bonded diamonds on the surface for increased cutting characteristics. Thermally induced phase transitions are assessed via Raman spectroscopy and reveal a negligible heat-affected zone.
Capabilities and advantages of laser ablation processes utilizing ultrashort pulses have been demonstrated in various applications of scientific and industrial nature. Of particular interest are applications that require high geometrical accuracy, excellent surface integrity and thus tolerate only a negligible heat-affected zone in the processed area. In this context, this work presents a detailed study of the ablation characteristics of common ultrahard composite materials utilized in the cutting tool industry, namely polycrystalline diamond (PCD) and polycrystalline cubic boron nitride composite (PCBN). Due to the high hardness of these materials, conventional mechanical processing is time consuming and costly. Herein, laser ablation is an appealing solution, since no process forces and no wear have to be taken into consideration. However, an industrially viable process requires a detailed understanding of the ablation characteristics of each material. Therefore, the influence of various process parameters on material removal and processing quality at 10 ps pulse duration are investigated for several PCD and PCBN grades. The main focus of this study examines the effect of different laser energy input distributions, such as pulse frequency and burst pulses, on the processing conditions in deep cutting kerfs and the resulting processing speed. Based on these results, recommendations for efficient processing of such materials are derived.
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