Water-soluble Coolant Research Articles

A Study on Anomaly Detection of Water-Soluble Coolant Using Internal-Sensors

The quality of water-soluble coolant is managed based on the maintenance schedules provided by a manager including periodic replacement of coolant. Post-maintenance is adopted when an anomaly is detected in the daily measurements. However, the reliability of management is dependent upon on the competence and experience of an operator. Condition monitoring allows users to detect critical changes in a water-soluble coolant. In contrast to the conventional method, condition monitoring can be assumed to be continuous and remote using ICT technologies. In this study, the spindle motor and NC data were utilized as internal sensors to monitor the quality of water-soluble coolant. The signal obtained from this sensor system can be easily broadcasted to the Internet as digital data and extended to an automatic data analysis using AI and machine learning in the future. It can be stated that this study enhances continuous and remote monitoring of water-soluble coolant and has the possibility of monitoring the changes in sludge concentration and Brix%. However, the sensor data cannot be used as an absolute index to estimate the quality of water-soluble coolant. It is a valuable indicator only when it is analyzed in combination with other sensor data such as pH and Brix%. The method proposed in this study can be widely extended to monitor the condition of water-soluble coolant and cutting tools.

Effect of MQL and nanofluid on the machinability aspects of hardened alloy steel

The current research comprises of various machinability aspects of 4340 hardened alloy steel which are scrutinized with in context of improvements in main cutting force, tool flank wear, crater wear, surface roughness, micro-hardness, machined surface morphology, chip morphology, chip reduction coefficient and apparent coefficient of friction under three different cutting fluid applications i.e. compressed air, water soluble coolant and nanofluid (using eco-friendly radiator coolant as the base fluid and Al2O3 as the nanoparticle) using uncoated cermet cutting inserts and a comparative assessment was performed to select which fluid performed better in terms of various machining attributes among three cutting fluids. The minimum quantity lubrication technique (MQL) was used in which a smaller volume of coolant sprinkled at high pressure. This method is found as the most effective alternative to minimize health risks and machining costs, which is quite high in other setups. The test specimen was machined at three different cutting speeds i.e. 100, 120 and 140 m/min along with two machining parameters i.e. feed and depth of cut were kept constant respectively at 0.2 mm/rev and 0.4 mm. Outcomes made a conclusion that Al2O3 enriched ecofriendly nanocoolant outperformed both compressed air and water soluble coolant in terms of every machinability aspects.

Performance evaluation of various cutting fluids using MQL technique in hard turning of AISI 4340 alloy steel

The present study emphasizes on various machinability aspects using different cutting fluids. The effect of cutting fluids on various machining forces, tool flank wear and chip thickness are carried out using the minimal quantity lubrication technique (MQL). This method predicts minimal health risks and economical aspect compared to other techniques. It is experimentally observed that depth of cut and speed was the principal cutting parameter affecting the cutting force and feed force and speed as the principal cutting parameter for the radial force for compressed air and water soluble coolant. Instead, depth of cut, feed and speed were the principal cutting parameters influencing cutting force, feed force and radial force, respectively using nanofluid. In the flank wear analysis, nanofluid performed the best followed by water soluble coolant and compressed air. Finally the mathematical models were developed for the machining forces with 95% confidence level using Minitab 16 which is frequently used for statistical data analysis. ANOVA analysis, Anderson-Darling test and normal probability plot was used to inspect the effectiveness, adequacy, authenticity and statistical significance of the developed model.

Performance evaluation of aluminium oxide nano particles in cutting fluid with MQL technique in turning of hardened AISI 4340 alloy steel

The current research comprises various machinability aspects of 4340 hardened alloy steel which are scrutinized with in context of improvements in main cutting force, tool flank wear, crater wear, surface roughness, microhardness, machined surface morphology, chip morphology, chip reduction coefficient and apparent coefficient of friction under three different cutting fluid applications i.e. compressed air, water soluble coolant based MQL, and nanofluid (using eco-friendly radiator coolant as the base fluid and Al2O3 as the nanoparticle) based MQL technique using cermet cutting inserts and a comparative assessment was performed to select which fluid performed better in terms of various machining attributes among three cutting fluids. The minimum quantity lubrication technique was used in which a smaller volume of coolant sprinkled at high pressure. This method is found as the most effective alternative to minimize health risks and machining costs, which is quite high in other setups. The test specimen was machined at three different cutting speeds i.e. 100,120 and 140m/min along with two machining parameters i.e. feed and depth of cut were kept constant respectively at 0.2mm/rev and 0.4mm. Outcomes made a conclusion that Al2O3 enriched ecofriendly nano-coolant outperformed both compressed air and water soluble coolant in terms of every machinability aspects.

Study on Recycle of Water-soluble Coolant

Study on Recycle of Water-soluble Coolant

Property and Recyclability Change of Corrosion-Inhibition-Improved Amine-Free Water-Soluble Cutting Fluid with Repeated Recycling

Cutting fluid is commonly used during metal cutting process for cooling and lubrication. Fluid types are generally classified into mineral or fatty oils and water miscible oils. In Japan, the former is called water-insoluble coolants, and the latter is called water-soluble coolants. Water-insoluble coolants are specified as dangerous material by the Japanese law due to its flammability. Therefore, the water-insoluble coolants are not appropriate for unmanned operation of machine tools. Therefore, the usage rate of water-soluble coolants is increasing. Water soluble coolants are diluted with a water by several ten times. The waste management of the water-soluble coolant become important for environment-conscious green manufacturing. We have been developing a recycling system for water-soluble coolants. In the recycle system, water is extracted from the waste coolant and the water is then reutilized as a diluent of a new coolant. We have developed various types of chemical or bio-chemical water recovery methods for recycling systems. We found a commercially available amine-free water-soluble coolant is suitable for the recycling system. The processing time, processing cost, and the biochemical and chemical oxygen demand of the extracted water are improved by the amine-free water soluble coolant compared with a conventional amine-containing coolant. However, its corrosion inhibition performance was poor in general machining applications. Our cooperative company developed a prototype of a corrosion-inhibition-improved amine-free water-soluble cutting coolant. The prototype coolant showed a good stability and cooling and lubricating performances, and its recyclability was as good as that of conventional amine-free coolants. In this study, we focused on repeated recycling of the prototype coolant. We repeatedly applied the water recycling process to the recycled coolant. The recyclability of the prototype coolant was not affected by repeated recycling; however, process residues increased with the number of recycles, and a deterioration was noticed in the corrosion-inhibition performance of the coolant diluted with recycled water.

Cutting Characteristics of Binderless Diamond Tools in High-Speed Turning of Ti-6Al-4V – Availability of Single-Crystal and Nano-Polycrystalline Diamond –

In this study, the tool performance of two types of binderless diamond tools – single-crystal diamond (SCD) and nano-polycrystalline diamond (NPD) – is investigated in the high-speed cutting of titanium alloy (Ti-6Al-4V) with a water-soluble coolant. The NPD tool allows for a larger cutting force than the SCD tool by dulling of the cutting edge, despite NPD being harder than SCD. This large cutting force and the very low thermal conductivity of NPD yield a high cutting temperature above 500°C, which promotes the adhesion of the workpiece to the tool face, thereby increasing tool wear. Based on the morphology of the tool edge without scratch marks and the elemental analysis by energy-dispersive X-ray spectroscopy (EDX) of both the flank face and the cutting chips, diffusion-dissolution wear is determined to be the dominant mechanism in the diamond tool. A thin TiC layer seems to be formed in the boundary between the diamond tool and the titanium alloy at high temperatures; this is removed by the cutting chips.

Recyclability and Performance Stability of Corrosion Inhibition Improved Amine-Free Water-Soluble Cutting Coolant

The concern for environmental problems has been increasing rapidly in recent years. Water-soluble coolants are widely used in machining processes. To reduce management costs and the environmental load of water-soluble coolants, the authors studied a recycling system for water-soluble coolants. With this recycling system, water is extracted from a waste coolant by chemical or biochemical treatment; the recovered water is re-utilized as a diluent for a new coolant. Coolant recyclability depends on the coolant type. Most water-soluble coolants contain alkanolamines for corrosion inhibition and maintenance of putrefaction prevention. However, alkanolamines are difficult to eliminate from water-soluble coolants by chemical and physical waste treatment processes. Some amine-free, water-soluble coolants have been developed and are commercially available. The reduction of environmental load in the treatment of waste coolants is anticipated for amine-free coolants. We applied the recycling process to a commercially available amine-free, water-soluble coolant. The amine-free coolant showed good recyclability and lubricating performance. However, the corrosion inhibition performance of the coolant was inadequate for use in general machining. Recently, our cooperative company developed a prototype amine-free, water-soluble coolant with improved corrosion inhibition. In this study, we experimentally examined the recyclability and performance stability of this newly developed coolant. The experimental results showed that the new amine-free coolant has good corrosion inhibition equivalent to conventional amine-containing coolants. In addition, the recyclability, stability, and cooling and lubricating performance of the coolant are equal to conventional amine-free coolants. The amine-free, water-soluble coolant with improved corrosion inhibition has the advantage that it can be used in the recycling system for water-soluble coolants.

GS0528 転動体研削時の回転数がクーラントの圧力分布に及ぼす影響

Superfinishing is one of the processing methods that can make a sliding surface of precision components with mirror surfaces. In general superfinishing, we have used a water-insoluble coolant that has high viscosity. However, smaller surface roughness than that of grind stone surfaces cannot be expected by using water-insoluble coolant because of its characteristic, i.e. grain size and materials, etc. In this study, we conducted fluid analysis and determined the pressure distribution between the grind stone and the rolling elements using water-soluble coolant. As a result, we clarified that effects of the revolution speed and the viscosity on pressure distribution are differences slightly.

Recyclability and Performance Stability of Corrosion Inhibition Improved Amine-Free Water-Soluble Cutting Coolant

Recyclability and Performance Stability of Corrosion Inhibition Improved Amine-Free Water-Soluble Cutting Coolant

Wear analysis when machining AISI 304 with ethylene glycol/TIO2 nanoparticle-based coolant

This paper discuss the tool life and wear mechanism in the end-milling of AISI304 stainless steel using a TiN-coated carbide insert with water-soluble coolant and nanoparticle-based coolant (TiO2/EG). The cutting variables are cutting speed, feed rate, and axial depth. The end-milling operation using nanoparticle-based coolant (TiO2/EG) obtains a high tool life compared with the end-milling operation using water-soluble coolant. In general, the tool failure when milling with water-soluble coolant was flank wear, cracking, chipping, and fracture at a cutting distance of 720 mm, but the milling process with nanoparticle-based coolant (TiO2/EG) showed chipping and fracture at a cutting distance of 1200 mm. According to ISO 8688-2-1989 (E), the wear criterion for milling with water-soluble coolant is reached at an average cutting distance of 800 mm, but milling with nanoparticle-based coolant (TiO2/EG) reached the ISO 8688-2-1989 (E) wear criterion at a cutting distance of 1300 mm. The SEM and EDX spectra show that there are nanolayers of Ti nanoparticles from the nanofluid embedded in and filling the holes in the insert, forming a layer which acts as a thermal bridge for the cutting insert. Attrition and oxidation at the cutting edge were the main tool wear mechanisms present during the end-milling operation with nanoparticle-based coolant (TiO2/EG). An oxide layer formed during the oxidation wear which shielded the cutting tool from impact during the milling process.

Performance Stability of Recycle Amine-Free Water-Soluble Coolant in Long Term Operation

Recently, the concern for the environment has been increasing rapidly. In machining processes, the treatment of water-soluble coolants waste has caused environmental problems. Water-soluble coolants contain surfactants, preservatives, and corrosion inhibitors for maintaining the stability and performance of the coolants. To reduce the management cost and environmental effect of water-soluble coolants, the authors have been studying a recycling system for water-soluble coolants. In the recycling system, oil-free recycle water is isolated from the coolant waste and reused as a diluent of the new coolant. The authors have been developing different types of water recovery methods for the recycling system, and the recovered water from the coolant waste has potential as a diluent for a new coolant. In this report, we focused on the amine (alkanolamine) -free water-soluble coolant. Some amine-free water-soluble coolants have been developed and are commercially available. A reduction in the environmental effect in the waste treatment of coolants is expected with amine-free coolants. We have demonstrated that the amine-free water-soluble coolant has equal or better cooling and lubricating performance compared with the conventional amine-containing coolant. In addition, the amine-free coolant shows good recyclability for the recycling system. The processing time of the recycling treatment of the amine-free coolant has been decreased by half with our recycling process compared with the conventional amine-containing coolant. In this report, we examined the stability, cooling performance and lubricating performance of the recycle amine-free water-soluble coolant in long term operation. The recycle amine-free water-soluble coolant is operated in a 3-axis machining center for several months. We observed concentration, pH, corrosion inhibition performance, cooling performance, and lubricating performance of the coolant. The results from these experiments show the amine-free water-soluble coolant has the advantage to use in the recycling system for water-soluble coolant.

A Dynamic Observation Concept to Keep Water-Soluble Coolant in Normal Condition for Long Time

We propose a dynamic observation concept to pretend aged degradation of water-soluble coolant. The first-hand observation of coolants by a CCD microscope is extremely useful for monitoring the drastic appearance change. The appearance changes of coolant also could be monitored by combining the reflectance changes from the Red, Green and Blue LED lights. The physical process of absorbing light is occurred only at the specific wavelength in the water-soluble coolants. The absorbance at the specific wavelength would become a reliable indicator to predict the controlled condition of water-soluble coolant. Setting up these sensing systems to the machine tools make it possible to observe the coolant dynamically and on real time.

Influence of Grinding Atmosphere on Grinding Characteristics of CFRP (Effect of Soluble Coolant or Liquid Nitrogen Supply)

CFRP (Carbon Fiber Reinforced Plastics), which is increasingly applied to airplanes, automobiles, production equipment for electronic device, and so on, is machined after molding process. Grinding is often used for edge finishing of CFRP parts. This paper deals with the influence of grinding atmosphere on grinding characteristics of CFRP by the experimental investigation of ground surface characteristics, surface finish, grinding force, grinding temperature, etc. in surface grinding of unidirectional CFRP using a vitrified bond diamond wheel with the water soluble coolant and the liquid nitrogen in addition to dry grinding. The grinding temperature has been measured by a developed thermocouple system using carbon fibers being made up CFRP and a constantan wire setting between CFRP specimens. The grinding temperature at wheel contact area on CFRP is higher than the glass-transition temperature of CFRP at larger setting wheel depth of cut. The wet grinding prevents in worsening ground surface of CFRP and increasing grinding force that occur in dry grinding of CFRP. The liquid nitrogen makes some effect on prevention in wheel loading and delamination of carbon fibers in dry grinding of CFRP, however the grinding force supplying liquid nitrogen becomes larger than that in dry grinding because of an increase in hardness of CFRP by freeze up. The bending strength of ground CFRP, which suggests the scale of affected layer, is improved by supplying the water soluble coolant and the liquid nitrogen in grinding process.

A023 Investigation of Grinding Temperature of Carbon Fiber Reinforced Plastics

In machining of carbon fiber reinforced plastic (CFRP), machining heat aflects an interface with matrix resin and carbon fibers to lead delamination of carbon fibers. In this study, the measuring technique of the grinding temperature of grain at grinding point and that at wheel contact area of CFRP is developed based on the Seebeck effect, and influence of grinding atmosphere, in which dry grinding, wet grinding supplying water-soluble coolant or that supplying liquid nitrogen, on grinding temperature of CFRP is experimentally investigated.

Filter-Less Purification of a Water-Soluble Coolant by Using PGA Based Flocculants and Microbubbles

In grinding processes, water-soluble working fluid is in heavy usage to maintain and improve a grinding performance. In this paper, effects of the water quality (soft or hard) were studied in a new filter-less purification system using commercially available Polyglutamic acid based flocculants and the microbubble coolant at the same time. As a result of the experiments, it was found that the collection rate of the suspended matters by the magnetic adsorption removal for the hard water became lower compared to the soft water, due to the Ca component contained in rich. It has also been made clear that by removing the suspended matters in the fluid flocked by the flocculant using the magnetic adsorption method and overflowing the residue with the microbubbles after that, the collection rate of the suspended matters in the soft water fluid would become higher than 99%. In the case of the hard water as well, improvement of the collection rate by the microbubbles was confirmed.

A Pragmatic Approach to Reduce Environmental Load in Machining Process

We discussed the coolant composition which can guarantee both the excellent fluid abilities as the cutting fluid and the good treatability as the recyclable material toward the development of sustainable cutting fluid system. We prepared three distinctive coolants; amine-free (EX-102), mineral-oil and amine free (α-1000) and amine-containing (EM-L) coolants. All of the coolants have excellent emulsion stability for standing in the natural condition butα-1000 and EM-L showed a good anti-rust properties while EX-102 showed a rather poor anti-rust property for the cast iron chips. The vegetable oil has a rather poor stability in lubricating performance than that of the mineral oils and synthetic ester. The alkaline substances dissolved in the amine-free coolant can be separated by the surfactant treatment as well as the oil contents, while some alkaline substances, maybe di-ethanol amine, are still retained in the recovered water from the amine-containing coolant. The activated carbon treatment showed no significant change for all of the coolant. Amine-containing coolant forms no stable emulsion; the recovered water cant utilize as a diluents of newly water-soluble coolant while the amine-free coolants can form a stable emulsion to a certain extent. The most direct attack to make the cutting fluid sustainable would be developing a new emulsifier and corrosion inhibitor that can substitute for amine compounds and can show a good treatability like the amine-free cutting fluid.

D28 アミンフリー水溶性加工液の運用とリサイクル性の検討(OS13 環境適応型加工(2))

D28 アミンフリー水溶性加工液の運用とリサイクル性の検討(OS13 環境適応型加工(2))

Filter-Less Purification of Grinding Fluid by Using PGA Based Flocculant

Water soluble coolant has been widely used as machining fluid owing to its environment- friendly characteristic, fine protection property and low price. However, as this type of coolant is perishable, a large amount of labor is required for its maintenance of the coolant. Moreover, in high precision machining, separation of minute machined chips generated during grinding and machine oil from the coolant is indispensable, and a special filtering-device and other equipments are necessary. In this paper, a method to purify water-soluble grinding fluid using PGA based flocculant was examined. As a result of experiments, it was clarified that the suspended matters such as grinding swarf or free abrasive grains in the fluid can be removed at the collection rate of more than 99%. A new filter-less coolant purification technology was established by combined use of micro bubble coolant.

Effect of Dry Cutting on Force and Tool Life When Machining Aerospace Material

Cutting fluids, usually in the form of a liquid, are applied to the chip formation zone in order to improve the cutting conditions. Cutting fluid can be expensive and represents a biological and environmental hazard that requires proper recycling and disposal, thus adding to the cost of the machining operation. For these reasons dry cutting or dry machining has become an increasingly important approach; in dry machining no coolant or lubricant is used. This paper discussed the effect of the dry cutting on cutting force and tool life when machining aerospace materials (Haynes 242) with using two different coated carbide cutting tools (TiAlN and TiN/MT-TiCN/TiN). Response surface method (RSM) was used to minimize the number of experiments. ParTiAlN Swarm Optimisation (PSO) models were developed to optimize the machining parameters (cutting speed, federate and axial depth) and obtain the optimum cutting force and tool life. It observed that carbide cutting tool coated with TiAlN performed better in dry cutting compared with TiN/MT-TiCN/TiN. On other hand, TiAlN performed more superior with using of 100 % water soluble coolant. Due to the high temperature produced by aerospace materials, the cutting tool still required lubricant to sustain the heat transfer from the workpiece.