Semi-dry Machining Research Articles

Evaluation of the superabsorbent coolant as a new approach to semi-dry machining

This work presents a novel coolant suitable for different machining processes. The focus of this study is applying superabsorbent coolant (SAC) during milling of hardened H13 steel and evaluating the possibility of utilizing superabsorbent material as a coolant and comparing with dry and flood conditions. The use of SAC is a novel method of semi-dry machining that proves the performance of hydrogels as a coolant and opens a new window for industrial applications. The main purpose besides improving machining performance is that a suitable condition has been provided to use benefits of nanoparticles (higher thermal conductivity and lubricity) safely and prevent distribution of nanoparticles and other chemical additives in the air which can cause serious occupational and environmental problems as well. The results of machining studies indicate that SAC can considerably reduce cutting force, improve surface integrity, and increase tool life. In addition, the friction conditions at the cutting zone have been improved. The results show a lower surface roughness of the chip surface.

Robust Design of the Optimal Supply Condition of Cutting Fluid in Semi-dry Machining

Robust Design of the Optimal Supply Condition of Cutting Fluid in Semi-dry Machining

Study on the Effects of Abrasive and Coolant-Lubricant Types on Minimum Quantity Lubrication-MQL Grinding

In dry grinding, as there is no coolant lubricant to transfer the heat from the contact zone, generation of surface damages are not preventable. Promising alternatives to conventional flood coolant applications are also Minimum Quantity Lubricant (MQL) or Near Dry Machining (NDM) or Semi Dry Machining (SDM). This research has been conducted to study the influence of the abrasive and coolant-lubricant types on the minimum quantity lubrication (MQL) grinding performance. One type of CBN and three types of conventional wheels (corundum) were tested. The tests were carried out in presence of fluid, air jet and eleven types of coolant-lubricants, as well as in dry condition. The results indicate that the finest surface quality and the lowest grinding forces could be obtained when grinding with CBN wheels. In the case of conventional wheels, the coarser wheel induces much proper grinding results.

An investigation on surface grinding of AISI 4140 hardened steel using minimum quantity lubrication-MQL technique

In dry grinding, as there is no coolant lubricant to transfer the heat from the contact zone, generation of surface damages are not preventable. Promising alternatives to conventional flood coolant applications are also Minimum Quantity Lubricant (MQL) or Near Dry Machining (NDM) or Semi Dry Machining (SDM). As the name implies, MQL machining uses a very small quantity of lubricant delivered precisely to the cutting zone. Often the quantity used is so small that no lubricant is recovered from the parts. Any remaining lubricant may form a film that protects the parts from oxidation or the lubricant may vaporize completely due to high temperatures of the cutting zone. A number of studies have shown that MQL grinding can show satisfactory performance in practical grinding processes. However, there has been little investigation of cutting fluids to be used in MQL grinding. In this study, several grinding fluids, including mineral, vegetable and synthetic esters oil, are compared on the basis of the grinding forces and surface quality properties that would be suitable for MQL grinding applications, to develop a multifunctional fluid having the MQL results such as cooling, lubrication and high ecological and environmental safety performances. The grinding performance of fluids is also evaluated in dry and conventional fluid grinding techniques.

Mathematical analysis of the micromachining of 316L stainless steel

The interactions between 316L stainless steel and a multi-point cutting tool create significant opportunities to understand how dry milling of hardened materials affects micromachining conditions. The present work not only compares various computational approaches to the solution of shear plane and tool face temperatures during semi-dry machining, but also discusses how the accompanying machining attributes react to large changes in the coefficient of friction caused by changes in the type of coated cutting tool used for micromachining. The paper accounts for the changes in material properties during semi-dry machining as a function of changes in temperature and also shows how stresses and strains are affected by significant changes in the magnitude of the coefficient of friction.

Minimal quantity lubrication-MQL in grinding of Ti–6Al–4V titanium alloy

Titanium and its alloys are attractive materials due to their unique high strength–weight ratio that is maintained at elevated temperatures and their exceptional corrosion resistance. The major application of titanium has been in the aerospace industry. On the other hand, titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. The problems that arise during grinding of titanium alloys are attributed to the high specific energy and high grinding zone temperature. Significant progress has been made in dry and semidry machining recently, and minimal quantity lubrication (MQL) machining in particular has been accepted as a successful semidry application because of its environmentally friendly characteristics. A number of studies have shown that MQL machining can show satisfactory performance in practical machining operations. However, there has been few investigation of MQL grinding of special alloys like titanium alloys and the cutting fluids to be used in MQL grinding of these alloys. In this study, vegetable and synthetic esters oil are compared on the basis of the surface quality properties that would be suitable for MQL applications. The cutting performance of fluids is also evaluated using conventional wet (fluid) grinding of Ti–6Al–4V. As a result, synthetic ester oil is found to be optimal cutting fluids for MQL grinding of Ti–6Al–4V.

Mechanical properties and cutting performance of nanocomposite Cr–Si–N coated tool for green machining

In this paper, comparative studies on mechanical properties and cutting performance between CrN and Cr–Si–N coatings for green micro end-milling were conducted. Ternary Cr–Si–N coatings, in which Si was incorporated into CrN, were synthesized onto WC–Co substrates using a hybrid system of arc ion plating and sputtering techniques. The high hardness of Cr–Si–N coatings was related to the composite microstructure consisting of the fine CrN crystallites and amorphous Si3N4. The average friction coefficient of Cr–Si–N coatings gradually decreased with increase of Si content in CrN coatings. Cutting tests were carried out to evaluate the characteristics of micro cutting in vertical machining center using ultra-high speed air turbine spindle. An integrated evaluation system of cutting tools was introduced. Consequently, the Cr–Si(9.3 at.%)–N coated end-mill using semi-dry machining showed good cutting performance under ultra-high speed cutting condition.

Feasibility Study for Using a Supersonic-Emulsified Cutting Fluid System in an Aircraft Parts Machining Process

It is an urgent subject to reduce environmental burden in manufacturing processes. In a machining process, although an MQL (Minimal Quantity Lubrication) system has been utilized in the past few years, its application to aluminum alloy machining is difficult because of its cooling capability. To overcome this obstacle, we developed an S.S.E. (Supersonic Emulsification) system which uses a water soluble cutting liquid for semi-dry machining. By applying supersonic 0/W emulsification just before the supply to cutting point, we were able to create an O/W emulsion without using an emulsifier which has a high environmental burden. One of the advantages of this process is to create emulsion with only using a very small amount of energy. Another is ease of retrofitting conventional machine tools with this system. When performing a cutting test using this S.S.E for semi-dry machining the cutting force was reduced by 15% compared to that by using the conventional “flood type emulsion machining”. This could bring out approximately 4% reduction in power consumption for axis rotation. In a feasibility cutting test for machining air craft parts could also observe 2.3-5.4% reduction in power consumption. The required quality of the machined part was also maintained. Finally, when using a 10% Rape Seed Emulsion supplied at 12 ml/min, 30% reduction in oil cost could be achieved.

Dry and semi-dry machining using finely crystallized diamond coating cutting tools

Finely crystallized diamond coatings with smooth surfaces have recently been developed by the authors. In the present study, shaft tools with these new coatings were applied to dry and semi-dry machining of highly adherent aluminum alloys whose efficient means of dry machining have not yet been established for. In comparison to the case of conventional diamond coatings with rough surfaces, more than four times longer durability of drills was realized in perfectly dry condition. In the case of minimum quantity of lubricant condition, the lifetime was found again to be more than four times longer and successfully achieved the largest improvement of diamond-coated drills ever reported in semi-dry condition.

Tribological Characteristics and Cutting Performance of Lubricant Esters for Semi-dry Machining

In semi-dry machining, such as minimal quantity lubrication (MQL) machining, a very small amount of a lubricant plays an Important role to achieve a successful operation. This study investigates the tribological behavior of lubricants for semi-dry application in connection with their cutting performance. In MQL turning, synthetic biodegradable esters are superior to a vegetable oil and provide the satisfactory cutting performance compared with a conventional cutting fluid of flood supply. Their tribological action is further evaluated with the aid of tool surface analysis and the adsorption characteristics of a model ester are fundamentally examined using a controlled atmosphere machining apparatus.

2821 超微結晶ダイヤモンド被膜を用いたドライおよびセミドライ加工

2821 超微結晶ダイヤモンド被膜を用いたドライおよびセミドライ加工

軟質金属切削における塗布効果 （第３報） 浸漬法による潤滑機構中の塗布効果の役割究明

Oil-submerged cuttings were conducted on an NC precision cutting apparatus in order to measure the influence of the lubricant applying effect on lubrication. The tool and work were completely submerged into cutting fluids which contained in an oil bath. Any deviation in lubrication due to oil supplying method, operators, and etc. can be eliminated by this method. The cutting forces in the oil-submerged cutting were compared to those in the lubricant applying effect cutting. The comparison indicates that the lubricant applying effect shares a high percentage in the lubrication. In other words, it plays a major role in lubrication in most cutting conditions, which enables semidry machining.

Development of a Semi-dry Machining Process

Development of a Semi-dry Machining Process

A Synthetic Ester as an Optimal Cutting Fluid for Minimal Quantity Lubrication Machining

Significant progress has been made in dry and semidry machining recently, and minimal quantity lubrication (MQL) machining in particular has been accepted as a successful semidry application because of its environmentally friendly characteristics. A number of studies have shown that MQL machining can show satisfactory performance in practical machining operations. However, there has been little investigation of the cutting fluids to be used in MQL machining. In this study, several fluids, including vegetable and synthetic esters, are compared on the basis of the physical properties that would be suitable for MQL applications. The cutting performance of fluids is also evaluated using actual MQL operations. As a result, biodegradable synthetic esters are found to be optimal cutting fluids for MQL machining.