Surface conditioning and texturing of cutting tool edges for the optimization of machining processes
Zusammenfassung der Projektergebnisse
The target of the project was to develop an innovative approach for preparation of cutting tools by changing the tool face and flank properties through the application of laser technology. Short pulsed laser radiation was used to manufacture a surface textured by partial remelting. Ultra short pulse laser ablation was utilized to manufacture tribological effective surface micro structures (dimples). These “tribostructures” can reduce the friction between tool surfaces and material during the cutting process and hence can provoke a reduction of cutting forces. The main challenges were to develop a robust laser ablation strategy for the target dimples on hard metal / cemented carbide, the measurement method of the dimples, which must be reliable, repeatable and operable according to production requirements and to determine their influence on the tool performance in an abstract manner. Both laser processes could be successful conducted in a robust and repeatable process strategy using automated data generation software. While the remelted texture could not lead to any tribological improvement, the micro dimples could influence the cutting forces and the friction in the cutting process. It could be shown, that the dimple size has to be chosen according to the target system, meaning to take into account the material to be cut as well as the cutting process parameters. These results could be supported by simulation works, giving the possibility to pre-design micro dimples based on the stress situation detail of the target system and hence reduce the extent of prior fundamental investigations using tribometers. Based on the task to acquire a surface topography containing roughness remaining from conventional manufacturing as well as laser generated dimples with minimum information loss, 4 optical measurement systems were chosen and analyzed in relation to the acquisition of textured surfaces. The used measurement techniques were: Confocal microscope (Nanofocus µSurf Custom), Low coherence interferometry (Bruker NPFLEX), Focus-Variation (Alicona InfiniteFokus) and chromatic confocal sensor (FRT MicroProf). The evaluation of these measurement techniques for the surface characterization was conducted based on the test specimen presented in the previous sub-section. Every field was measurement 5 times with the different equipment and analyzed. The overall system characteristic with relation to the aimed application was summarized in a decision table. Based on the results, the low coherence interferometry was chosen. The different textured surface measurements were analyzed and processed based on the parameters of the DIN EN ISO 25178. For the analysis of the measurement data an analysis of the material content has been carried out by means of the Abbott curve. Using the Abbott curve for a material, the relative proportion of the surface topography has been detected as well as all Sk and surface volume parameters. In addition, a motif analysis was performed to find every single dimple and analyze its individual features. Every evaluation field was consequently also characterized based on its geometrical parameters, as number of dimples, average height, average diameter, average of the smallest / largest diameter, mean spherical radius fitted in the dimple cavity and location of Dimple. Relevant correlations between the laser processing strategy and the resulting surface could thus be revealed: • The average depth of the dimple is strongly correlated with the Svk. • With increasing laser intensity the parameters Sk and Spk increases. • Average depth of the dimple is strongly correlated with Vvv (with increasing Dimple depth the also Vvv also increases). • The laser intensity is correlated with Vmp, Vmc, Vvc (with increasing laser intensity the Vmp, Vmc, Vvc parameters also increase). • Number of laser pulses correlate with the average depth of the dimple.
Projektbezogene Publikationen (Auswahl)
-
3D surface parameters (ISO 25178-2): Actual meaning of Spk and its relationship to Vmp. In: Precision Engineering 40 (2015) 106–111
Sinatora, A. et al.
-
Effect of Solid-State Laser Parameters on the Surface’s Topography Formation During Texturization of Hard Metal Cutting Tools. In: Journal of Aerospace Technology and Management. Jg. 7, 2015, Nr. 1, S. 63-69
Oliveira Teixeira, P. H. de; Reis, A. G.; Janssen, A.
-
Analysis of dimple textured surfaces on cutting tools. In: Journal of the Brazilian Society of Mechanical Sciences and Engineering. 2016
Stoeterau, R. L.; Janssen, A.; Mallmann, G.
-
Friction Analyses of Dimple-Structured Surface. In: Journal of Mechanics Engineering and Automation. Jg. 6, 2016, Nr. 6, S. 269-276
Stoeterau, R. L.; Janssen, A.; Mallmann, G.
