Study About Minimum Quantity Lubrification in Bearing Holes Bored with Pcd Tools in Aluminum Alloy

Cutting Fluid in Abundancy – CFA is a standard cooling technique used in machining due to the good relationship between quality and productivity. However, due to sustainability problems, economic, social, and environmental, several research types have been carried out worldwide about replacing or eliminating these inputs in the cutting process. In this work, three full factorial Design of Experiment - DoE were used to verify the performance and feasibility of replacing the Cutting Fluid in Abundance - CFA by Minimum Quantity Lubrification – MQL during the bearing of holes bored with Polly Cristaline Diamond – PCD tools in aluminum alloy. The input variables were cutting speed (𝑣𝑐), feed per knife (𝑓𝑧) and depth of cut (𝑑𝑜𝑐). While output variables were diameter and circularity deviation. For each machining atmosphere, dry, CFA, and MQL, a full factorial DoE (2 3 ) was performed with test and replicate. A total of 48 runs were performed. The main conclusion is that MQL showed similar CFA results, as proven by the mean hypothesis test. Based on the results of this work, it can be affirmed that MQL could replace the CFA technique.

The Performance of Polycrystalline Diamond (PCD) Tools Machined by Abrasive Grinding and Electrical Discharge Grinding (EDG) in High-Speed Turning

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.

Flank-milling of Integral Blade Rotors made in Ti6Al4V using cryo CO2 and Minimum Quantity Lubrication (MQL)

This paper presents the machining of Ti6Al4V Integral Blade Rotors (IBR) using CO2 as cryogenic cooling. This kind of component is typical in gas turbines, pumps and other rotary machines. Flank milling technique using diamond polycrystalline (PCD) tools using CO2 and Minimum Quantity Lubrication (MQL), denominated CryoMQL, is an alternative to conventional oil emulsions. The proposed approach implies a balance between technical and environmental issues, and it makes feasible the use PCD tools avoiding the high temperature reactivity of Ti6Al4V alloy with this type of cutting tools. CO2 must be supplied and injected onto the cutting zone, avoiding the risks of dry ice formation and clogging of both pipes and nozzles. For this purpose, a new device for CO2 delivery was developed, using gas and liquid CO2.

Study of cutting force and tool wear during turning of aluminium with WC, PCD and HFCVD coated MCD tools

Enormous developmental work has been made in synthesis of metastable diamond by hot filament chemical vapor deposition (HFCVD) method. In this paper, micro-crystalline diamond (MCD) was deposited on WC–6 wt.% Co cutting tool inserts by HFCVD technique. The MCD coated tool was characterized by the scanning electron microscope (SEM), X-ray diffraction (XRD) and micro Raman spectroscopy (μ-RS). A comparison was made among the MCD tool, uncoated tungsten carbide (WC) tool and polycrystalline diamond (PCD) tool during the dry turning of rolled aluminum. The various major tests were conducted such as surface roughness, cutting force and tool wear, which were taken into consideration to establish a proper comparison among the advanced cutting tools. Surface roughness was measured during machining by Talysurf. The tool wear was studied by SEM after machining. The cutting forces were measured by Kistler 3D-dynamometer during the machining process. The test results indicate that, the CVD coated MCD tool and PCD tool produced almost similar results. But, the price of PCD tools are five times costlier than MCD tools. So, MCD tool would be a better alternative for machining of aluminium.

Evaluation of surface roughness, dimensional and shape accuracy of Al₂O₃ ceramics in hardened state after milling

The effect of technological parameters of machining on surface roughness, dimensional and shape accuracy in the process of milling Al2O3 ceramics in hardened state was evaluated. The unique properties of ceramic materials cause more and more interest in them in various branches of industry. Ceramics in the hardened state can be processed using unconventional methods and conventional methods while maintaining the appropriate technological parameters. Ceramics cutting tests were carried out in a hardened state (face and shape milling) on a CNC milling machine using PCD tools. Geometric surface structure study and measurements of geometric dimensions were made.