MQL with water in cylindrical plunge grinding of hardened steels using CBN wheels, with and without wheel cleaning by compressed air

et al. 2018

Among the alternatives to reduce the application of cutting fluid in machining industry, minimum quantity lubrication (MQL) technique has been promising, although it can impair cooling properties and the ability of the fluid to penetrate the cutting region. In order to further reduce the quantity of oil and to improve the characteristics of the cooling lubrication method, this work aims to compare the effect of MQL with different ratios of oil/water (1:1, 1:3, and 1:5) on the performance of plunge cylindrical grinding of alumina. Lubricating effect and effective penetration of fluid in the cutting zone are considered the most relevant factors. The lowest surface roughness value was obtained with the application of conventional flood cooling, followed by MQL 1:1. In comparison to conventional MQL technique, reduced surface roughness and grinding wheel wear could be obtained by applying MQL with water.

“…Moreover, the material used (AISI 1020) is a soft steel and does not influence wheel wear. Reliable results using this method were obtained in [19][20][21][22].…”

Section: Methodsmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Application of minimum quantity lubrication with addition of water in the grinding of alumina

Lopes

Ventura

et al. 2018

“…Moreover, according to researches carried out by Malkin and Guo [7], Marinescu et al [13] and Ruzzi et al [19] in grinding of hardened steels with conventional abrasive grinding wheels, higher the feed rate, the higher and faster is the advancement of grinding tool against the workpiece. On this way, the surface roughness increases because of the higher cutting forces that are generated by the faster advancement of the grinding wheel moving at higher infeed rate, thereby promoting vibrations and leading to deterioration of the surface finish [20].…”

Section: Surface Roughnessmentioning

confidence: 99%

Contribution to cylindrical grinding of interrupted surfaces of hardened steel with medium grit wheel

Mello

et al. 2018

Self Cite

Grinding is generally the first choice to provide combination of both superior surface finish and closer dimensional tolerances in a machined component. This process can be employed in manufacturing of continuous and interrupted surfaces. Crankshafts and engine piston rings are examples of ground precision mechanical components having interrupted surfaces. However, the specific literature about grinding of interrupted surfaces is still scarce. In this context, aiming to further contribute to the understanding of the behavior of surface integrity of interrupted surfaces during grinding, this paper presents an experimental investigation of interrupted surfaces ground with white aluminum oxide grinding wheel. Discs of AISI 4340 hardened steel with different number of grooves (2, 6, and 12) on the external surface were tested. Experiments with discs without interrupted surface were also carried out for comparisons. In addition to the number of grooves, three values of infeed rate (0.25, 0.50, and 0.75 mm/min) were used as input parameters. The output parameters investigated were the geometric errors (surface roughness and roundness) of the workpiece material as well as the diametric wheel wear. Analysis of variance (ANOVA) test was performed to verify any statistical difference among the output variables. Results showed that both surface finish and roundness of workpieces with interrupted surfaces were higher than those obtained for continuous surface. These parameters also increased with infeed rate up to 0.50 mm/min, whereas the grinding wheel wear was more sensitive to number of grooves and infeed rate. No thermal damages were observed on the machined workpieces under the conditions investigated.

“…When the lubrication property of cooling-lubrication technique is reduced, grinding forces increase, then more power is required to perform cutting. Ruzzi et al [31] reported that the when a cooling capacity in grinding of hardened steel with conventional abrasive wheel is achieved, the workpiece material temperature will be kept in lower levels, so its mechanical resistance will be retained, which in turn, hampers the cutting action by the wheel grits, thereby requiring higher grinding power.…”

Section: Grinding Powermentioning

confidence: 99%

Plunge cylindrical grinding with the minimum quantity lubrication coolant technique assisted with wheel cleaning system

Bianchi

Hildebrandt

et al. 2017

Self Cite

MQL technique is considered as a cleaner machining compared to the conventional coolant delivery one, thereby ensuring environmental sustainability and economic benefits. However, one of problems commonly reported when using the MQL technique is the wheel clogging phenomenon as a result of the inefficient chip removal from the cutting zone, then the chips lodge inside the pores of the grinding wheel, adversely affecting the quality and the finishing of the final product. In this context, this study was carried out to evaluate the performance of the minimum quantity lubrication coolant technique assisted with a wheel cleaning jet (MQL + WCJ) in plunge grinding of hardened steel. This cooling-lubrication technique was tested using the following flow rates: 30, 60, and 120 ml/h. Comparative tests were also carried out with the conventional coolant technique, as well as with the traditional MQL technique (without the wheel cleaning jet). The output variables used to assess the efficiency of the MQL + WCJ technique are roughness, roundness, workpiece microhardness, grinding wheel wear, and power consumption. The results showed that the machining with the MQL + WCJ technique outperformed the traditional MQL technique in all the output parameters investigated. Also, the efficiency of the MQL + WCJ technique increased with flow rate, thereby being an alternative coolant delivery technique in grinding due to cleaner environment, more sustainable and lower consumption of fluid compared to conventional coolant one. No thermal damages and cracks on the machined surface and sub-surfaces were observed after grinding AISI 4340 steel, irrespective of the technique.