Evaluation of 3D tool wear in machining by successive stereo-photogrammetry and point cloud processing

Abstract

Procjena trošenja alata ima značajan utjecaj na kvalitetu proizvoda, kao i na učinkovitost proizvodnog procesa. Primijenjena je procjena trošenja alata temeljena na iskustvu i ukupnom vremenu trajanja obrade. Taktilni mehanički uređaji i optički mikroskop su također primijenjeni. Predlaže se i primjenjuje inovativna optička metoda mjerenja trošenja alata koja se zasniva na 3D skeniranju uporabom stereo-fotogrametrije i triangulacije. Metodom je moguće točno izmjeriti trodimenzionalne devijacije na ukupnoj površini rezne pločice, jer je trodimenzionalni vektor odstupanja oblika dobiven pomoću milijun točaka. Trodimenzionalnu funkciju svekupnog istrošenja alata moguće je dobiti i bez uklanjanja alata s alatnog stroja. Određivanje istrošenja alata kao trodimenzionalne funkcije nudi mnoštvo informacija prema kojima je moguće dovesti u vezu pojedinačne oblike trošenja alata s mogućim uzorcima trošenja.The tool wear evaluation has a very strong impact on the product quality as well as efficiency of the manufacturing process. Experience-based assessment of tool wear and total cumulative time of operation has been applied. Tactile mechanical sensing devices and optical microscopes have been applied as well. This paper proposes and applies an inovative optical tool wear measurement method. It is based on 3D optical sensing using stereo-photogrammetry and triangulation. It offers high accuracy 3D dimensional deviation measurement spanning over the total tool surface, hence 3D deviation vectors from some reference shape are obtained simultaneously for millions of points. The overall tool wear shape function in 3D is generated, in many cases even without disassembly of the tool. Capturing the tool wear as a 3D shape function potentially offers abundant information towards diagnostics in terms of correlating the particular tool wear shape function with respective potential causes