Influence of cooling conditions on the machining process under MQCL and MQL conditions

Abstract

Original scientific paper The paper presents the results of investigation of the influence of conditions of forming emulsion and oil mist on the chip shape and surface roughness of X10CrNi18-8 stainless steel during turning. In the tests, the following machining operations have been compared: dry machining, cooling by the MQCL (Minimal Quantity Cooling Lubricat) method, cooling by the MQL (Minimum Quantity Lubricat) method. The tests have been performed in two stages. In the first stage, the influence of the mass flow of the active medium on the chip shape and on the Ra and Rq roughness parameters of the machined surface have been determined. The purpose of stage two was to determine the influence of the MQL and MQCL method on the selected indices of the machining process as compared to dry machining as a function of variable cutting speed. It has been found that, under MQCL and MQL conditions, the area of formation of elemental chips and ones with the shape of short spirals is wider as compared to dry turning. With increased mass flow of emulsion and oil, tangled chip is formed. Cooling by the MQCL and MQL method results in reduction of the selected roughness parameter values by 2 % to 42 % as compared to dry machining. Keywords: emulsion mist; chip shape; MQCL; MQL; oil mist; surface roughness Utjecaj uvjeta hlađenja na postupak obrade u uvjetima MQCL i MQLIzvorni znanstveni članak U radu se predstavljaju rezultati istraživanja utjecaja uvjeta stvorenih djelovanjem emulzijske i uljne izmaglice na oblik strugotine i površinsku hrapavost nehrđajućeg čelika X10CrNi18-8 tijekom tokarenja. Uspoređivane su sljedeće vrste obrade: na suho, hlađenje MQCL metodom (minimalne količine maziva za hlađenje), hlađenje MQL metodom (minimalne količine maziva). Ispitivanje je provedeno u dva stadija. U prvom je određen utjecaj protoka mase aktivnog medija na oblik strugotina i Ra i Rq parametre hrapavosti obrađivane površine. U drugom je stadiju trebalo odrediti utjecaj MQL i MQCL metode na izabrane indekse postupka obrade u odnosu na obradu na suho kao funkcije promjenljive brzine rezanja. Ustanovljeno je da je, u MQL i MQC uvjetima, područje stvaranja elementarnih strugotina i onih u obliku kratkih spirala šire, u usporedbi s tokarenjem na suho. S povećanim protokom mase emulzije i ulja, stvaraju se zamršene strugotine. Hlađenjem MQL i MQC metodom dolazi do smanjenja vrijednosti izabranih parametara hrapavosti za 2 % do 42 % u usporedbi s obradom na suho.

Structural and Microhardness Changes After Turning of the AISI 1045 Steel for Minimum Quantity Cooling Lubrication

“…However, due to tool life and poor surface quality, methods based on minimum quantity lubrication-MQL (Ref 3, 4, 13, 14, 17, 18)-and minimum quantity cooling lubrication-MQCL ( Ref 9,18,19)-are good alternatives. In both these methods, the amount of active medium in the form of aerosol typically does not exceed 50 ml/h ( Ref 4,18,20), while for flood cooling method flow rate of MWFs is over the 500 ml/h ( Ref 20).…”

“…In both these methods, the amount of active medium in the form of aerosol typically does not exceed 50 ml/h ( Ref 4,18,20), while for flood cooling method flow rate of MWFs is over the 500 ml/h ( Ref 20). In the MQL method, oil is the main active medium (Ref 4,13,18); hence, its main purpose is to lubricate, while in the MQCL method an emulsion concentrate is usually the main medium, which is why in this method the primary task is to cool the cutting zone and therefore to dissipate as much heat as possible (Ref 12,21).…”

Predictive compensation of thermal deformations of ball screws in CNC machines using neural networks

“…The literature describes methods based on design, manner of operation, thermal stabilisation and thermal compensation [10][11][12]. The most common solutions are a direct measurement system, cooling of the ball screw transmission, or preheating of the machine tool [13,14]. Most of these methods enable significant improvement in positioning accuracy in the case of medium and large machines.…”

The influence of cooling method on cutting power during turning of 316L austenitic steel

“…W obu metodach ilość CCS w postaci aerozolu nie przekracza na ogół 50 ml/h [3,5] [5,6], dlatego jej głównym zadaniem jest chłodzenie strefy skrawania, a tym samym odprowadzanie jak największej ilości ciepła [8]. W celu poprawy własności smarnych CCS, czyli zmniejszenia tarcia pomiędzy narzędziem a materiałem obrabianym, wprowadza się do nich specjalne dodatki EP/AW.…”

“…W obu metodach ilość CCS w postaci aerozolu nie przekracza na ogół 50 ml/h [3,5] i metody te znalazły już zastosowanie w procesach: toczenia [3,5,6], frezowania [4], wiercenia [7] i szlifowania [1]. W metodzie MQL medium czynnym jest przede wszystkim olej [1, 3÷5, 7], stąd jej głównym zadaniem jest smarowanie.…”