Analysis of cooling-lubrication methods on the performance of grinding processes

Kareepadath Santhosh, Deepa (avtor), Krajnik, Peter (mentor), Pušavec, Franci (komentor)

Grinding is a manufacturing process, extensively used as a finishing process to attain high precision in the production of components. Given the high specific energy and elevated temperatures involved, as well as the demands of high cutting speeds and potential for wheel loading, grinding typically relies on large quantities of cooling-lubrication fluid. However, in order to support sustainable manufacturing, alternative approaches that reduce oil consumption are required. Recent advancements in cooling and lubrication, such as single-channel lubricated carbon dioxide cooling (LCO₂), have demonstrated potential in machining with defined cutting geometries. However, they remain less explored in grinding applications. This doctoral thesis first investigated the effects of various cooling-lubrication methods, specifically emulsion and LCO₂ combined with minimum quantity lubrication (MQL), on pin-grinding of hard materials like cemented carbide. The investigation examined a number of measures, including grinding forces, force ratio, specific energy, and wheel loading mechanisms. Furthermore, the impact of LCO₂+MQL and conventional flood cooling on the performance of the surface grinding was evaluated, with a particular focus on surface roughness, residual stresses, microhardness, and cost-effectiveness. The wear of diamond tools was analysed by comparing the effects of dry conditions, emulsion, and LCO₂ in single-point dressing. This was achieved by measuring dressing forces and temperature, which allows the evaluation of dressing aggressiveness. Additionally, the study examined the topography of grinding wheel and the wear of diamond grits under varying overlap ratios and depths of dressing. The findings suggest that LCO₂+MQL can be as effective as conventional flood cooling, especially at lower aggressiveness levels, and can significantly reduce wear of the dresser in the single-point diamond-dressing process.

• Jezik: Angleški jezik
• Ključne besede: grinding, sustainability, liquid carbon dioxide, minimum quantity lubrication, cryogenic machining, diamond
• Vrsta gradiva: Doktorsko delo/naloga
• Tipologija: 2.08 - Doktorska disertacija
• Organizacija: FS - Fakulteta za strojništvo
• Založnik: [D. Kareepadath Santhosh]
• Leto izida: 2025
• Št. strani: XXVI, 115 str.
• PID: 20.500.12556/RUL-169282
• UDK: 620.181.4:621.9.016:621.923(043.3)
• COBISS.SI-ID: 240188419
• Datum objave v RUL: 22.05.2025

Sekundarni jezik

• Jezik: Slovenski jezik
• Naslov: Analiza hladilno-mazalnih metod na učinkovitost brusilnih procesov

Izvleček

Brušenje je proizvodni postopek, ki se pogosto uporablja kot postopek končne obdelave za doseganje visoke natančnosti pri izdelavi komponent. Zaradi visoke specifične energije in povišanih temperatur ter zahtev po visokih rezalnih hitrostih in možnosti zapolnitve brusa se pri brušenju običajno porabijo velike količine hladilno-mazalne tekočine. Za podporo trajnostni proizvodnji so potrebni alternativni pristopi, ki zmanjšujejo porabo hladilno-mazalne tekočine. Nedavni napredek na področju hlajenja in mazanja, npr. enokanalni dovod tekočega ogljikovega dioksida (LCO2) in olja, je pokazal potencial pri odrezavanju z definirano geometrijo orodja. Uporaba te metode pri brušenju pa ostaja manj raziskana. V doktorski disertaciji so bili raziskani učinki različnih metod hlajenja in mazanja, zlasti emulzije in LCO2 v kombinaciji z minimalno količino mazanja (ang. Minimum Quantity Lubrication - MQL), na brušenje materialov, kot so karbidne trdine. V raziskavi so bili analizirani številni parametri, vključno s silami brušenja, razmerjem sil, specifično energijo in mehanizmi obrabe brusa. Poleg tega je bil ocenjen vpliv LCO2+MQL in oblivajočega hlajenja z emulzijo na hrapavost obdelane površine, zaostale napetosti, trdoto in stroške obdelave pri konvencionalnem brušenju ravnih ploskev. Obraba diamantnih orodij je temeljila na primerjavi učinkov suhega ostrenja, emulzije in LCO2 hlajenja in mazanja pri eno-točkovnem ostrenju, kjer so bile merjene sile in temperature, kar omogoča oceno agresivnosti postopka. Poleg tega je študija vključevala analizo topografije brusa in obrabe diamantnih zrn pri različnih razmerjih prekrivanja in globinah ostrenja brusa. Ugotovitve kažejo, da je LCO2+MQL lahko enako učinkovito kot konvencionalno oblivajoče hlajenje z emulzijo, zlasti pri nižjih stopnjah agresivnosti, in da znatno zmanjša obrabo diamanta pri eno-točkovnem postopku ostrenja brusov.

• Ključne besede: brušenje, trajnostni razvoj, tekoči ogljikov dioksid, mazanje z minimalno količino, kriogeno odrezavanje, diamant