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Bachelor's Thesis
Author of thesis: Václav Raštica
Acad. year: 2025/2026
Supervisor: Ing. Aleš Polzer, Ph.D.
Reviewer: Ing. Vendula Sámelová, Ph.D.
This bachelor's thesis presents a systematic evaluation of surface texture on the functional tooth flank surfaces of two gear components from Festool professional power tools. Basic technical documentation was prepared for the measured specimens. In view of the tribological behaviour of involute gearing — specifically lubricant film formation, contact fatigue and wear — the selection of specific profile R-parameters (Ra, Rq) and areal S-parameters (Sa, Sq, S10z, Ssk, Vvc) in accordance with ISO 21920 and ISO 25178 was justified. Measurements were carried out using three methodologically distinct instruments: a contact stylus profilometer Taylor Hobson Form Talysurf 50, a non-contact optical system Alicona InfiniteFocus G5 based on focus variation, and a Taylor Hobson CCI Lite interferometer. Due to the complex geometry of the gear teeth, destructive specimen preparation was required; its feasibility was verified analytically in advance. Five repeated measurements were performed on each specimen. For specimen A, the measured values were Rq = 0.396 µm and Sq = 0.728 µm (TH CCI); for specimen B, Rq = 0.476 µm and Sq = 1.010 µm (TH CCI). The expanded measurement uncertainty reached U = 0.73 µm for the stylus profilometer and U = 0.20 µm for the optical methods. Conformity assessment according to ČSN EN ISO 14253-1 revealed that the measured values of both specimens fall within the uncertainty zone, and conformance with the drawing specification cannot be unequivocally declared. Based on the results, widening of the tolerance limits and the use of the Alicona InfiniteFocus G5 as a non-destructive metrological alternative are recommended.
Surface texture, metrology, tribology, functional parameters, gear teeth
Date of defence
09.06.2026
Result of the defence
Defended (thesis was successfully defended)
Grading
C
Process of defence
Student seznámil komisi se svojí bakalářskou prací formou prezentace. Otázky oponenta práce: 1. Otázka plně zodpovězena. 2. Otázka plně zodpovězena. 3. Otázka plně zodpovězena. Otázky komise k práci: 1. Jaký byl použit objektiv u měřícího zařízení Alicona Infinite Focus G5 a jak ovlivní použitý objektiv nejistoty měření? Otázka zodpovězena částečně. 2. Jaké jsou typy nejistot měření a co je ovlivňuje? Otázka plně zodpovězena. 3. Jaké byly cíle práce? Otázka plně zodpovězena 4. Jaké by byly další možné, vhodnější parametry textury povrchu pro daný účel? Otázka plně zodpovězena. 5. Co vyjadřuje parametr šikmosti? Otázka plně zodpovězena.
Language of thesis
Czech
Faculty
Fakulta strojního inženýrství
Department
Institute of Manufacturing Technology
Study programme
Engineering (B-STR-P)
Specialization
Manufacturing Technology (STG)
Composition of Committee
doc. Ing. Josef Chladil, CSc. (předseda) prof. Ing. Marek Sadílek, Ph.D. (místopředseda) prof. Dr. Ing. Miroslav Neslušan (člen) doc. Ing. Michal Šajgalík, PhD (člen) Ing. Karel Osička, Ph.D. (člen) Ing. Jiří Hajnyš, Ph.D. (člen) Ing. Martin Petrenec, Ph.D. (člen)
Supervisor’s reportIng. Aleš Polzer, Ph.D.
Grade proposed by supervisor: C
Reviewer’s reportIng. Vendula Sámelová, Ph.D.
Grade proposed by reviewer: C
Responsibility: Mgr. et Mgr. Hana Odstrčilová