Karakterizacija in napovedovanje učinka pulzirajočega visokotlačnega dovoda hladilno mazalne tekočine v proces struženja

doktorsko delo

Matjaž Kern (Author), Franci Pušavec (Mentor)

Abstract

Kljub napredku v odrezovalnih procesih in razvoju rezalnih orodij, je uporaba hladilno-mazalnih sredstev oz. tekočin (HMT) pri večini obdelav še vedno potrebna, kar je spodbudilo razvoj novih tehnologij mazanja in hlajenja. Poleg konceptov pri katerih se za hlajenje uporablja kriogene medije, se za obdelavo težko obdelovalnih materialov v industriji pojavlja uporaba visokotlačnega (VT) dovoda HMT. Prednosti, ki jih izkazuje visokotlačni dovod HMT, se odražajo v povečani obstojnosti orodja, nižjih temperaturah v rezalni coni, povečani rezalni hitrosti in produktivnosti, vendar je uporaba te tehnologije zaradi visoke hitrosti curka in močno pospešenih odrezkov (obstreljevanje obdelane površine) ter veliki potrošnji električne energije, močno zavrta. Kot pristop k problemu in spremembi fizikalnih mehanizmov VT odrezavanja, v doktorskem delu predstavljamo inovativno idejo oz. koncept pulzirajočega visokotlačnega dovoda HMT. V sklopu doktorske naloge je bil razvit sistem za sekvenčni nadzor odrezavanja s podporo VT curka, s katerim se pulzno nadzoruje pretok in tlak dovedene HMT in s tem mazalni, hladilni in lomilni učinek v odrezovalnem procesu. Z integracijo razvitega sistema v obdelovalni center je bilo na procesih struženja analizirano temeljno delovanje, so bili prepoznani fizikalni mehanizmi in so bile določene osnovne karakteristike pulzirajočega VT odrezavanja na podlagi odrezkov, obstojnosti orodja, rezalnih sil, rezalnih temperatur, integritete obdelane površine ter potrošnje el. energije. Uporaba pulzirajočega dovoda HMT ponuja možnost aktivnega nadzora nad obliko odrezkov, zato je bil izdelan model za napovedovanje deformacije odrezka in določitev kritičnega momenta, ki je potreben za lom odrezka. Analiza je pokazala smiselnost uporabe pulzirajočega VT dovoda HMT v procesu struženja z vidika zmanjšanja obrabe orodja, kakovosti obdelanih površin ter dviga produktivnosti s pridobljenim nadzorom nad dolžino odrezkov.

Keywords

disertacije;pulzirajoče visokotlačno odrezavanje;dovod hladilno-mazalne tekočine;struženje;odrezki;deformacija odrezkov;obremenitve orodja;

Data

Language:	Slovenian
Year of publishing:	2024
Typology:	2.08 - Doctoral Dissertation
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[M. Kern]
UDC:	621.9:621.941:681.7.048(043.3)
COBISS:	211030531
Views:	9
Downloads:	7
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Characterization and prediction of the effect of pulsating high-pressure cooling lubrication fluid supply on turning process
Secondary abstract:	Despite advancements in cutting processes and development of cutting tools, the use of cooling and lubrication fluids (CLF) remains essential in most machining operations, prompting the creation of innovative cooling and lubrication technologies. In addition to concepts in which cryogenic media are used for cooling, High-Pressure (HP) CLF systems are increasingly used for machining difficult-to-cut materials, offering benefits like longer tool life, lower cutting zone temperatures, higher cutting speeds, and improved productivity However, the use of this technology is severely limited due to the high CLF jet speeds, the highly accelerated chips (which damage the machined surface), and high power consumption. As an approach to address the problem and alter the physical interactions that occur during HP cutting process, an innovative idea or concept of pulsating high-pressure CLF supply is presented in this doctoral thesis. As part of the dissertation, a system was developed for sequential control of the cutting process with the support of the HP jet, which controls the flow and pressure of the supplied CLF and thus influences the lubrication, cooling and chip breaking effect in the cutting process. By integrating the developed system into a machining center, the fundamental operation was analysed in turning processes, the physical mechanisms were identified, and the fundamental characteristics of pulsating HP machining were determined based on chips, tool durability, cutting forces, cutting temperatures, surface integrity of the machined part, and electricity consumption. The use of pulsed CL supply offers the possibility to actively control the chip shape. Therefore, a model was developed to predict chip deformation and determine the critical moment for chip breakage. Analysis demonstrated the feasibility of using the pulsed HP CLF system in turning processes, reducing tool wear, improving surface quality, and increasing productivity by controlling chip length.
Secondary keywords:	dissertations;pulsating high-pressure machining;coolant application;turning;chips;chip deformation;cutting tool load;
Type (COBISS):	Doctoral dissertation
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za strojništvo
Pages:	XXVI, 170 str.
ID:	25266632