Analýza obrobitelnosti a výskytu trhlin ocelí 1.2363 a 1.2343ESR obrobených hloubení EDM

Analysis of Machinability and Crack Occurrence of Steels 1.2363 and 1.2343ESR Machined by Die-Sinking EDM

článek v časopise ve Web of Science, Jimp

en

Die-sinking electric discharge machining (EDM) is an indispensable technological operation, especially in the production of molds and all internal and external shapes and cavities. For this reason, the effect of machine parameter settings (open-voltage, pulse current, pulse on time, and pulse off time) on the machining of two types of steels, 1.2363 and 1.2343ESR, was carefully investigated using graphite or copper electrodes in 10mm × 10 mm or 100mm × 100 mm shapes. For this purpose, a two-level half factor experiment was performed with one replication at the corner points and two replications at the central points, with a total of 80 rounds. The subject of the evaluation was the topography and morphology of machined surfaces including a detailed analysis of surface and subsurface defects in the form of cracks including the creation of regression equations describing the probability of crack occurrence. Furthermore, a study of the local hardness change in the subsurface area was performed, and lamellas were also made and studied by transmission electron microscopy. It has been found that by using die-sinking EDM, it is possible to effectively predict the probability of cracking on machined surfaces and also on machine 1.2363 and 1.2343ESR steels with a very good surface quality of Ra 1.9 and 2.1 µm using graphite electrodes. These findings will ensure the production of parts with the required surface quality without cracks, which is a crucial aspect for maintaining the required functionality and service life of the parts.

Elektroerozivní hloubení je nepostradatelná technologická operace především při výrobě forem a všech vnitřních i vnějších tvarů a dutin. Z toho důvodu byl pečlivě zkoumán vliv nastavení parametrů stroje (Open-voltage, Pulse current, Pulse on-time a Pulse off-time) na obrábění dvou druhů ocelí 1.2363 a 1.2343ESR s použitím grafitových nebo měděných elektrod ve tvarech 10x10 mm nebo 100x100 mm. Za tímto účelem byl proveden dvou úrovňový poloviční faktorový experiment s jednou replikací v rohových bodech a dvěma replikacemi v centrálních bodech, celkem 80 kol. Předmětem vyhodnocování zde byla topografie a morfologie obrobených povrchů včetně detailní analýzy povrchových i podpovrchových defektů v podobě trhlin včetně vytvoření regresních rovnic popisujících pravděpodobnost výskytu trhlin. Dále byla provedena studie změny lokální tvrdosti v podpovrchové oblasti a také byly vyrobeny lamely a studovány pomocí transmisní elektronové mikroskopie. Bylo zjištěno, že je možné pomocí elektroerozivního hloubení obrábět oceli 1.2363 a 1.2343ESR s velmi dobrou jakostí povrchu Ra 1.9 a 2.1 µm s použitím grafitových elektrod.

Die-sinking electric discharge machining (EDM) is an indispensable technological operation, especially in the production of molds and all internal and external shapes and cavities. For this reason, the effect of machine parameter settings (open-voltage, pulse current, pulse on time, and pulse off time) on the machining of two types of steels, 1.2363 and 1.2343ESR, was carefully investigated using graphite or copper electrodes in 10mm × 10 mm or 100mm × 100 mm shapes. For this purpose, a two-level half factor experiment was performed with one replication at the corner points and two replications at the central points, with a total of 80 rounds. The subject of the evaluation was the topography and morphology of machined surfaces including a detailed analysis of surface and subsurface defects in the form of cracks including the creation of regression equations describing the probability of crack occurrence. Furthermore, a study of the local hardness change in the subsurface area was performed, and lamellas were also made and studied by transmission electron microscopy. It has been found that by using die-sinking EDM, it is possible to effectively predict the probability of cracking on machined surfaces and also on machine 1.2363 and 1.2343ESR steels with a very good surface quality of Ra 1.9 and 2.1 µm using graphite electrodes. These findings will ensure the production of parts with the required surface quality without cracks, which is a crucial aspect for maintaining the required functionality and service life of the parts.

hloubení EDM; elektroeroyivní obrábění; ocel; plánovaný experiment; trhliny; nastavení parametrů stroje

die-sinking EDM; electrical discharge machining; steel; design of experiment; cracks; machining parameters

19.04.2020

MDPI

Švýcarská konfederace

2079-6412

10

4

1–18

18