Machine tool system and electrolyzed water for machine tool

Abstract

[Problem] The purpose of the present invention is to provide: a machine tool system in which a lubricating liquid for machine tools that contains no oil-soluble material derived from mineral oil is used and circulated; and electrolyzed water serving as both an operating fluid for machine tools and a processing fluid. [Solution] This machine tool system is for operating a machine tool which works in an environment where an operating fluid for lubricating the machine tool and a processing fluid for processing a member to be processed mix with each other. Electrolyzed water containing no oil-soluble material derived from mineral oil is used as both the operating fluid and the processing fluid. The operating fluid that has been used for the lubrication and the processing fluid are mixed and collected as such and are returned to a supply path for the processing fluid and / or the operating fluid and circulated. The electrolyzed water is alkaline electrolyzed water containing at least an amine, a fatty acid, and a polymer.

Description

Machine tool systems and electrolyzed water for machine tools

[0001] The present invention relates to a machine tool system that uses and recycles lubricating fluid for machine tools that does not contain oil-soluble materials derived from mineral oil, and to electrolyzed water that can be used as a working fluid and machining fluid for machine tools.

[0002] A wide variety of lubricating oils are used as hydraulic fluids for the moving parts of machine tools used to process metal materials. Traditionally, oil-soluble lubricants based on mineral oils, fatty acid esters, etc. have been used as hydraulic fluids for lubrication purposes. In addition, additives containing chlorine, sulfur, phosphorus, etc. are often added to improve lubrication performance.

[0003] However, the lubricating oil and additives used as hydraulic oil are consumed as the machine tool operates, and much of this oil ends up in a recovery tank for processing oil (working fluid) such as cutting oil used on tools and workpieces during metal processing. The hydraulic oil in the recovery tank that has been mixed into the cutting oil has various adverse effects, such as degrading the performance of the cutting oil (details will be described later).

[0004] Meanwhile, in recent years, water-soluble lubricants have been used in cutting oils and other processing oils from the perspectives of reducing the environmental impact at the time of disposal, preventing fires, preventing decay, and the like (similar to the problems (i) to (vi) of hydraulic fluids described below), and there is a social demand for their further expansion (see Patent Documents 1 to 4). However, even if a water-soluble lubricant is used in cutting oils and other processing oils (working fluids (hereinafter referred to as "cutting fluids" or "working fluids" to distinguish them from oil-soluble agents)), if a hydraulic fluid containing an oil-soluble agent is used, as described above, the hydraulic fluid (working fluid (hereinafter referred to as "working fluid" or "lubricating fluid" to distinguish it from oil-soluble agents)) will be mixed into the working fluid in the recovery tank, thereby undermining the benefits of using a water-soluble agent or requiring additional measures. Specific problems with hydraulic fluids using oil-soluble agents as a base oil are listed below.

[0005] <Problems with lubricating fluids containing oil-soluble materials> (i) When hydraulic fluids are mixed with cutting oils and other fluids that have an oil-soluble material as their base (base oil), bacteria grow over time, causing spoilage and the resulting foul odor. (ii) The oil-soluble materials and additives that form the base of hydraulic fluids, as well as the bacteria that grow, irritate workers and cause rough hands. In addition, the preservatives that are added to reduce bacterial growth also contain substances that cause rough hands, such as chlorine, sulfur, and phosphorus.

[0006] Problems When Hydraulic Fluids Containing Oil-Soluble Materials Are Mixed with Machining Fluids Containing Water-Soluble Materials: (iii) When hydraulic fluids containing oil-soluble materials are mixed into machining fluids, stickiness on the workpiece can significantly impact downstream processes (e.g., paint peeling, poor adhesion, etc.). Conversely, cleaning the workpiece to avoid these impacts can lead to problems with the cleaning fluid's deterioration and disposal. (iv) When hydraulic fluids containing oil-soluble materials are mixed into machining fluids and the oil-water separation is not achieved, even if the machining fluid itself is water-soluble, the fluid must be discarded after use, making it disposable and non-reusable. Large-scale factories, in particular, generate large amounts of waste, and this must be addressed in response to societal demands for a decarbonized society. While there are methods for introducing equipment and processes that precisely separate the oil and water components, and methods for controlling the discharge rate of hydraulic fluid to prevent contamination of the machining fluid and reduce leakage into recovery tanks, these methods incur increased costs for introducing equipment and processes to separate the two components and for using hydraulic fluids that provide lubrication with a small discharge rate. (v) Even if a water-soluble machining fluid is used, even if measures such as the separation of the two fluids and limiting the amount of discharge are taken, if a small amount of hydraulic fluid containing oil-soluble materials is mixed in, the performance of the machining fluid will deteriorate over time, and the problem of waste fluid disposal through early replacement will remain. (vi) Even if a water-soluble machining fluid is used, if the hydraulic fluid remains oil-soluble, both cannot be reused, which generally does not meet the social demand for reduce, reuse, and recycle. In particular, the sliding parts of machine tools near the machining area are prone to contamination with the hydraulic fluid applied to the sliding parts when a large amount of machining fluid is released onto the workpiece or tool, and this poses a major problem of hydraulic fluid contamination, and particular attention should be paid to this issue.

[0007] JP 2002-167594 A JP 2008-221397 A JP 2010-23154 A JP 2012-91265 A

[0008] The present invention was created in light of the above problems, and aims to provide a machine tool system that solves the various problems mentioned above by making the lubricating fluid used as the working fluid for machine tools water-soluble, while maintaining the lubricity of the working fluid and machining fluids such as cutting fluid, and that can be circulated within the machine tool, as well as electrolyzed water as the working fluid and machining fluid used in this machine tool system.

[0009] The present invention provides a machine tool system that operates a machine tool that operates in an environment where a working fluid (mainly a spindle working fluid and a sliding surface lubricating fluid) used to lubricate the machine tool and a cutting fluid (cutting fluid, grinding fluid, polishing fluid, plastic working fluid, etc. (including oil-based and water-soluble fluids)) used to process workpieces are mixed, wherein electrolyzed water that does not contain oil-soluble materials derived from minerals is used for both the working fluid and the working fluid, and the working fluid and the working fluid are mixed and recovered as they are after the lubrication function has finished, and returned to the supply flow path for the working fluid and / or the working fluid for circulation, and the electrolyzed water is alkaline electrolyzed water blended with at least amines, fatty acids, and polymers.

[0010] Furthermore, it is preferable that the alkaline electrolyzed water contains 3 to 70 wt% of alkaline electrolyzed water as a solvent in the undiluted solution, and that the undiluted solution contains 5 to 25 wt% of the amines, 5 to 25 wt% of the fatty acids, and 3 to 50 wt% of the polymers as solutes.

[0011] More preferably, the alkaline electrolyzed water is blended as a stock solution with 10% to 20% by weight of the amines, 10% to 20% by weight of the fatty acids, and 3% to 15% by weight of the polymers.

[0012] Furthermore, when the alkaline electrolyzed water is used as a processing fluid, it is sufficient that the amines, fatty acids, and polymers are mixed in an amount of 20% by weight or less, 20% by weight or less, and 15% by weight or less, respectively.

[0013] Furthermore, it is preferable that the machine tool system comprises a recovery means arranged downstream of the lubrication flow path of the machine tool for mixing and recovering the working fluid and machining fluid after the lubrication function has finished, a discharge container connected to the recovery means for storing the working fluid and machining fluid, and a circulation means for sucking the working fluid and machining fluid from the discharge container directly through an inlet arranged at a position away from the bottom without separating oil and water, and returning the working fluid and / or working fluid to the supply oil path of the machining fluid.

[0014] In the machine tool system of the present invention, neither the machining fluid nor the hydraulic fluid contain oil-soluble materials derived from mineral oil, and both use electrolytic water, a common water-soluble material, and the hydraulic fluid and the machining fluid are mixed and recovered after use (after the lubrication function has ended), and are circulated as is back to the supply side. Therefore, since no oil-soluble materials are used in the flow paths (fluid paths) of the machine tool to begin with, and electrolytic water is used, the hydraulic fluid and the machining fluid are completely dissolved, mixed, and soluble when recovered, and therefore problems such as those described in (i) to (vi) above do not occur when a hydraulic fluid containing oil-soluble materials gets mixed into a machining fluid such as cutting fluid, even without separating the two fluids (for example, by sucking up the stored fluid while avoiding the vicinity of the liquid surface, as described in the embodiments below).

[0015] Specifically, (i) and (ii) the absence of oil-soluble materials that could serve as a nutrient source reduces bacterial growth, and because electrolyzed water is a water-soluble material, it also reduces the occurrence of anaerobic conditions (anaerobic bacteria) caused by oil-soluble materials separating or emulsifying and floating to the surface, covering the liquid surface. As a result, spoilage and unpleasant odors can be reduced. Furthermore, the absence of oil-soluble materials also prevents rough hands. Furthermore, (iii) the workpieces do not become sticky or contaminated due to adhesion of oil-soluble materials to them, making post-processing cleaning processes unnecessary or simple. This reduces the amount of cleaning fluid used and waste fluid generated by preventing the cleaning fluid from deteriorating, shortening the overall processing process (reducing manufacturing costs). Furthermore, (iv), (v), and (vi) it is possible to prevent the increase in costs and the increase in size and complexity of the machine tool that would accompany restrictions on the discharge amount of the working fluid and the installation of a two-liquid separation device, and it is possible to avoid deterioration of the performance of the machining fluid over time or the need for early replacement due to the mixing of a small amount of working fluid, and by making the working fluid and the working fluid the same, it is possible to achieve the demand for reuse.

[0016] Amines are added as alkaline agents to prevent oxidation of the electrolytic water liquid and maintain a high pH to improve rust prevention. Fatty acids are added to ensure lubricity and protect surfaces such as metals by adsorbing to them. Polymers are added to ensure viscosity as a working fluid.

[0017] In particular, the electrolyzed water used in this machine tool system is alkaline electrolyzed water to which at least 10% to 20% by weight of amines, 10% to 20% by weight of fatty acids, and 3% to 15% by weight of polymers have been added as a stock solution. Furthermore, the above blending ratio is suitable for the working fluid (lubricating fluid for sliding surfaces) because the stock solution is used as is, but when the alkaline electrolyzed water is used as a machining fluid, the stock solution can be diluted and used, and it has been found that, depending on the degree of dilution, it is sufficient for the blending ratio to be at least 20% by weight or less of the amines, 20% by weight or less of the fatty acids, and 15% by weight or less of the polymers.

[0018] The amines are preferably cycloamines, diamines, alkylamines, or glycolamines.

[0019] The amines mentioned above, which are suitable ingredients for maintaining the alkalinity of electrolyzed water used in this machine tool system, such as tertiary amines contained in PS and PX, are significantly susceptible to oxidation, resulting in discoloration and adhesion, making them unsuitable as working fluids (lubricants) for sliding surfaces, particularly those acting at the interface of castings. For example, ethanolamine alone is not suitable as a working fluid for alkaline electrolyzed water. Furthermore, some secondary amines among amines have been cited as carcinogenic, making them less suitable for widespread use as working fluids and machining fluids for machine tools. In contrast, examples of suitable amines for maintaining the alkalinity of alkaline electrolyzed water as working fluids (lubricants) and machining fluids for sliding surfaces of machine tools include cycloamines, diamines, alkylamines, and glycolamines.

[0020] The fatty acid is preferably nonanoic acid, caprylic acid, undecylenic acid, isononanoic acid, or isostearic acid.

[0021] The fatty acid generally has 8 to 18 carbon atoms, but it is preferable that the fatty acid be highly transparent so that the user can visually and tactilely recognize that it is water-soluble. When used as a hydraulic fluid or machining fluid for the machine tool system of the present invention, a fatty acid with 9 to 10 carbon atoms is preferred. Furthermore, in order to prevent poor sliding of sliding members, it is preferable to select a fatty acid that does not become solid (powder) at room temperature and remains liquid. Furthermore, when considering the materials of the machine tool and workpiece, it is also necessary to select a fatty acid from the perspective of rust prevention and stability.

[0022] From this perspective, preferred fatty acids as components of the electrolyzed water used in the hydraulic fluid and machining fluid of this machine tool system are straight-chain saturated and unsaturated fatty acids such as nonanoic acid, caprylic acid, and undecylenic acid, and isononanoic acid is a preferred branched fatty acid. On the other hand, when transparency after dilution with water is not important, isostearic acid, which has a large carbon number but satisfies the above-mentioned liquid properties, rust prevention properties, and stability, can also be selected and used as a suitable fatty acid.

[0023] The polymer is preferably a polymer of ethylene oxide (A), propylene oxide (B) or butylene oxide (C) and its derivatives, or a copolymer of any two of (A), (B) and (C) and its derivatives.

[0024] The polymer is incorporated to ensure the viscosity of the hydraulic fluid and improve lubrication on sliding surfaces. To prevent sliding problems, particularly slow movement when restarting after shutdown, it is necessary to reduce viscosity changes due to water evaporation, making polymers a necessary component of electrolyzed water used in hydraulic fluids and machining fluids. Suitable examples include polymers and derivatives of (A) ethylene oxide, (B) propylene oxide, or (C) butylene oxide, as well as copolymers of any two of (A) to (C) and derivatives thereof. Among these, for example, the average molecular weight of the polyalkylene glycol is preferably in the range of 400 to 4500, with one type containing nitrogen atoms in its structure for rust prevention of sliding components, primarily made of iron-based materials, in machine tools, and the other type preferably containing butylene glycol, which acts as a lubricant in machining fluids. The average molecular weight of butylene glycol is preferably 400 to 500.

[0025] It is also preferable that the alkaline electrolyzed water is a raw solution introduced as a working fluid with a pH of less than 10.0, and that the machining fluid is circulated after being adjusted to at least a pH of 9.0 or less.

[0026] As described above, this machine tool system is a circulation system in which a stock solution of alkaline electrolyzed water is added to the working fluid used as a lubricant for the sliding parts of the machine tool, and the initial filling of the working fluid is used by adding and diluting the stock solution with water, and then both are recovered and used again as the working fluid. When this alkaline electrolyzed water is initially added as the working fluid, the viscosity is ensured by the above-mentioned polymer, and the amount mixed into the working fluid is very small. In that sense, a strong alkaline solution is not considered to be a problem, but considering the impact on non-ferrous metal materials around the machine tool, a pH of <10.0 is preferable for the stock solution added as the working fluid. Furthermore, in order to avoid any restrictions on the workpiece being machined, it is preferable to adjust the working fluid to a weak alkaline solution, at least by diluting it to a pH of ≤9.0.

[0027] The alkaline electrolyzed water preferably does not contain preservatives but contains a pH buffer.

[0028] The alkaline electrolyzed water used as the lubricating fluid for the machine tool system does not contain additives such as chlorine, sulfur, or phosphorus (to reduce bacterial growth) in base oils derived from mineral oil, but instead contains an alkaline agent that promotes antiseptic effects by maintaining the pH of water-soluble materials. Therefore, the use of this working fluid and machining fluid not only (i) reduces odors caused by bacterial growth, but also (ii) is beneficial in preventing rough hands caused by the chlorine, sulfur, phosphorus, etc. contained in antiseptics used in conventional lubricating fluids for oil-soluble materials.

[0029] It is also preferable that the supply flow path through which the circulating means returns the working fluid and machining fluid from the discharge container is a machining fluid supply flow path, and that the circulating means cuts off communication with the working fluid supply flow path.

[0030] In this preferred machine tool system, the hydraulic fluid and machining fluid recovered by the circulation means are returned only to the machining fluid (e.g., cutting fluid) supply channel and reused as machining fluid. Instead of returning the fluid to the hydraulic fluid supply channel, the hydraulic fluid forms a channel through which fresh hydraulic fluid is constantly supplied. When using electrolytic water as a water-soluble material for the hydraulic fluid, evaporation occurs on the sliding surfaces during use, and strict performance requirements, such as viscosity, for lubricating fluid are required, necessitating the adjustment of the composition of the recovered fluid for reuse. On the other hand, machining fluids such as cutting fluid contain sludge (e.g., chips) that are particulate and cannot be completely filtered to avoid contamination. Using fluid containing this sludge as a hydraulic fluid can damage the sliding surfaces, which is particularly problematic for machine tools performing high-precision machining. Furthermore, since maintaining sufficient operating fluid volume is a key issue for machining fluids, and performance requirements for electrolytic water are not as strict as those for hydraulic fluids, it has been found that used machining fluids and similar hydraulic fluids can be recovered without distinction and reused simply by adding water to replenish the evaporated water. Therefore, in this preferred machine tool system, even when electrolyzed water is used as both the working fluid and the machining fluid, component control during operation is simplified, and in order to reduce costs and expand the market, used working fluid is actively allowed to enter the machining fluid side flow path, forming a circulation flow path as is, while the used machining fluid and working fluid are not allowed to enter the working fluid side flow path, thereby avoiding backflow.

[0031] In particular, the present machine tool system can be applied to machine tools having all the functions for machining workpieces, such as lathe function, milling function, grinding function, drilling function, and sawing function.

[0032] Another aspect of the present invention provides electrolyzed water for machine tools, which is used as a working fluid for lubricating machine tools and as a processing fluid for machining workpieces. This electrolyzed water for machine tools is the working fluid for the machine tool system described above and a processing fluid obtained by diluting it, and is alkaline electrolyzed water containing at least amines, fatty acids, and polymers.

[0033] As mentioned above, the amines are preferably cycloamines, diamines, alkylamines, or glycolamines.

[0034] As mentioned above, the fatty acid is preferably nonanoic acid, caprylic acid, undecylenic acid, isononanoic acid, or isostearic acid.

[0035] As before, the polymer is preferably a polyalkylene glycol or butylene glycol.

[0036] Furthermore, it is preferable that the alkaline electrolyzed water stock solution has a pH of less than 10.0.

[0037] Similarly to the above, the hydraulic fluid and machining fluid for the machine tool that contains a water-soluble material but no oil-soluble material and is used in the machine tool system may contain no preservatives but may contain a pH buffer.

[0038] According to the machine tool system and electrolyzed water used as the hydraulic fluid and machining fluid for the machine tool of the present invention, the hydraulic fluid of the machine tool does not contain oil-soluble materials derived from mineral oil, and both the hydraulic fluid and the machining fluid are water-soluble, so the machining fluid can be circulated within the machine tool without separating the two liquids, oil and water.

[0039] Fig. 1 is a perspective view of an NC lathe device as an example of a machine tool that employs the machine tool system of the present invention. Fig. 2 is a schematic diagram showing an example of the configuration of flow paths for hydraulic fluid and machining fluid in a conventional machine tool system. Fig. 3 is a block diagram showing an example of the configuration of the conventional machine tool system of Fig. 2. Fig. 4 is a schematic diagram showing an example of the configuration of flow paths for hydraulic fluid and machining fluid in the machine tool system of the present invention. Fig. 5 is a block diagram showing an example of the configuration of the machine tool system of the present invention of Fig. 4. Best Mode for Carrying Out the Invention

[0040] An embodiment of the machine tool system of the present invention is described below. This machine tool system is applicable to various machine tools, such as cutting and grinding machines, that use a working fluid for sliding surfaces and a working fluid for workpiece machining locations. In this specification, FIG. 1 illustrates an NC lathe as an example of a machine tool that employs this machine tool system. In particular, a perspective view of a horizontal NC lathe, in which the spindle (the workpiece rotation axis) is oriented horizontally, is shown as an example of an NC lathe. Furthermore, FIGS. 2 and 4 show schematic diagrams of a vertical NC lathe, typically used for large-scale lathe machining, as an alternative to the NC lathe shown in FIG. 1. Additionally, FIG. 2 illustrates an example of a conventional machine tool system using this vertical NC lathe, and FIG. 4 illustrates an example of the present machine tool system using the same vertical NC lathe.

[0041] As shown in FIG. 1, a general-purpose horizontal NC lathe 10 has two spindles (C1 axis 14, C2 axis 16) arranged on a base 12 at a distance from each other so that their axes (the longitudinal direction of the lathe (Z-axis direction)) are the same or parallel to each other. A workpiece 18 is mounted on both the C1 axis 14 and the C2 axis, and the spindles rotate as indicated by arrows A and B. A lower bed 22 is mounted on the base 12, and an upper bed 24 is mounted on the lower bed 22, sliding relative to the lower bed 22 in the Z-axis direction. A headstock 26 is mounted on the upper bed 24, sliding relative to the upper bed 24 in the Y-axis direction. A tool spindle 20 is mounted on the headstock 26, and moves up and down relative to the headstock 26 in the X-axis direction. A tool (not shown) is chucked at the tip of the tool spindle 20. With this configuration, in the perspective view of the horizontal NC lathe device shown in FIG. 10, the cutting edge of the tool approaches and moves away from a desired position on the workpiece 18 that is rotating along its axis, thereby cutting the workpiece 18.

[0042] As mentioned above, FIG. 2 shows an example of the configuration of a conventional machine tool system using a vertical NC lathe 100, while FIG. 3 shows an example of the configuration of a new machine tool system using the same vertical NC lathe 100 as in FIG. 2. Note that components in FIGS. 2 and 3 with the same last two digits as those in FIG. 1 represent the same components. The vertical NC lathe 100 is a lathe type that performs turning by placing a workpiece on a rotary table with a vertical rotation axis, like a potter's wheel, and is suitable for machining workpieces with large diameters. Specifically, the rotary table 130 carrying the workpiece 118 rotates about an axis OO, and the tool spindle 120 of the headstock 126 approaches and moves away from the rotating workpiece 118, cutting the workpiece 118 with a tool 132 held at its tip.

[0043] <<Example of a Conventional Machine Tool System (See Figures 2 and 3)>> Next, the lubricating fluid supply flow path in a conventional machine tool system using this vertical NC lathe 100 (hereinafter also simply referred to as "NC lathe 100") will be described with reference to Figures 2 and 3. Figure 2 shows an example of the configuration of a conventional machine tool system using the NC lathe 100, and Figure 3 shows a block diagram illustrating an overview of the conventional machine tool system shown in Figure 2. Note that, as the conventional NC lathe 100, the lubricating fluid used when machining the workpiece 118 with the tool 132 is based on a water-soluble material, and the working fluid used to lubricate the sliding surface of the tool spindle 120 and the rotating shaft of the turntable 130 is based on a mineral oil-based oil material. The arrows in Figure 3 indicate the flow of the working fluid or hydraulic fluid, and the thickness of the arrows represents the flow rate.

[0044] The NC lathe device 100 is equipped with an external or internal storage tank 134, which is comprised of a first storage tank (discharge container) 134a and a second storage tank 134b. Regarding the "machining fluid," a predetermined amount of new machining fluid 136 is poured into the first storage tank (discharge container) 134a before operation begins. (The structures of the first storage tank 134a and the second storage tank 134b will be described later.) When the NC lathe device 100 begins operation, the machining fluid 136 stored in the first storage tank 134a is pumped up by a pump (not shown), transported through an intake passage 138 to the machine tool body, and then discharged from a discharge port 138a to a machining location near the workpiece 118 or tool 132. After the released machining fluid 136 has lubricated and cooled the machining area, it falls from the workpiece 118, the rotary table 130, and other surrounding parts where it has scattered, and is collected in a collection container (collection means (e.g., a so-called oil pan)) 140 that receives all of the released machining fluid.

[0045] The used machining fluid collected in the collection container 140 is discharged from a discharge port 142a through a discharge flow path 142 disposed downstream thereof into the first storage tank 134a. While Fig. 2 shows the machining fluid in the collection container 140 being transported to the first storage tank 134a through the discharge flow path 142, other flow path configurations may be used as long as the machining fluid in the collection container 140 is discharged into the first storage tank 134a and functions as a single collection and storage container (see Fig. 3). For example, the collection container 140 and the first storage tank 134a may be directly connected, or the machining fluid may be temporarily assembled from the collection container 140 and transported to the first storage tank 134a. The machining fluid in the collection container 140 contains sludge 144 (sediment such as cutting chips) generated during machining, and the sludge 144 settles to the bottom of the used machining fluid stored in the first storage tank 134a.

[0046] The machining fluid stored in the first storage tank 134a is pumped into the suction passage 138 through a suction port 138b located at a predetermined height so as not to pump up sludge 144 that settles at the bottom, forming a circulation passage for reuse as machining fluid (the second storage tank 134b and the like will be described later). As is clear from Fig. 3, this circulation passage allows the machining fluid, once poured into the first storage tank 134a in the initial state, to be reused many times thereafter, except for the addition of a reduced amount or for periodic maintenance, and does not require waste disposal of unnecessary machining fluid.

[0047] Next, regarding the "hydraulic fluid," hydraulic fluids used in conventional machine tool systems are primarily composed of oil-soluble materials, regardless of the components of the machining fluid, and when new hydraulic fluid 152 is initially filled into the hydraulic fluid filling tank 150, it is subsequently filled appropriately to make up for any small amounts that have been lost. The hydraulic fluid 152 in the hydraulic fluid filling tank 150 is generally divided into a first hydraulic fluid supply path 154 on the tool spindle 120 side and a second hydraulic fluid supply path 154 on the turntable 130 side, and is supplied to the sliding parts 151 (see FIG. 3) of the tool spindle 120 and the turntable 130, respectively. This hydraulic fluid is supplied to lubricate the sliding parts 151, and although it is not released in large quantities like the hydraulic oil described above, a small amount does leak out of the sliding surfaces of the tool spindle 120 and the turntable 130. The leaked working fluid 152 falls downward from the tool spindle 126, the tool 132, the tool spindle 126, the tool 132, the rotary table 130, etc., and much of it reaches the recovery container 140 arranged to recover the machining fluid 136 (since the recovery container 140 and the first storage tank 134a may be an integrated member in some cases, FIG. 3 illustrates the fluid reaching the entire recovery and storage means). As a result, the liquid in the recovery container 140 becomes a mixture of the oil-soluble components of the working fluid 152 and the water-soluble components of the machining fluid 136, and reaches the first storage tank 134a via the discharge flow path 142.

[0048] As described above, the first storage tank 134a is intended to store and reuse the machining fluid 136, but in reality, it stores machining fluid 136 mixed with working fluid 152. In the mixed liquid of machining fluid 136 and working fluid 152 stored in the first storage tank 134a, working fluid 152, which is an oil-soluble component, floats near the liquid surface due to the difference in specific gravity, and machining fluid 136, which is a water-soluble component, remains below it.

[0049] The machine tool system using the conventional NC lathe device 100 shown in Figure 2 has a configuration in which the machining fluid 136 and the working fluid 152 are separated into two fluids so that only the machining fluid 136 can be pumped from the suction flow path 138, circulated, and reused.

[0050] The machining fluid 136 containing oil-soluble working fluid 152 that has reached the first storage tank 134a first enters and accumulates in the area marked with a circle 1. The partition 134c, which opens downward, allows the machining fluid 136 to enter the area marked with a circle 2 (see arrow α). At this time, sludge 144 settles to the bottom, and the oil-soluble working fluid 152 forms a layer of separated or emulsified working fluid 152 near the upper liquid surface of the area marked with a circle 1. Below this, machining fluid 136 with a significantly reduced content of oil-soluble working fluid 15 accumulates. Therefore, the liquid that enters and accumulates in the area marked with a circle 2 is mostly composed of working fluid 136 that does not contain oil-soluble working fluid 15. The separated or emulsified oil-soluble working fluid 152 near the upper liquid surface of the area marked with a circle 1 is discharged to the second storage tank 134b through a waste flow path 142, the suction side of which is located near the liquid surface, and is then discarded to the outside. This accomplishes the first stage of two-liquid separation, which generally separates the machining fluid 136 from the mixture of the hydraulic fluid 152 and the machining fluid 136 (including the sludge 144).

[0051] Furthermore, machining fluid 136 in the region marked with a circle 1 passes through partition 134d, whose upper end is lower than partition 134c, and enters region marked with a circle 3 (see arrow β). Then, through partition 134e, whose upper end is higher than partition 134d and whose lower end is open, it enters region marked with a circle 4 (see arrow γ). As a result, even if oil-soluble working fluid 152 remains near the upper liquid surface in region marked with a circle 2, most of it is removed from machining fluid 136 that enters region marked with a circle 4. Furthermore, machining fluid 135 in region marked with a circle 4 is pumped into intake flow path 138 from suction port 138b, which is positioned below the liquid surface and higher than the bottom, forming a circulation flow path where it is reused as machining fluid. This achieves the second-stage two-liquid separation, in which machining fluid 136 is largely separated from the mixture of working fluid 152 and machining fluid 136.

[0052] <<Example of a Machine Tool System of the Present Invention (See Figures 4-5)>> Next, an example of a lubricant supply flow path in a machine tool system of the present invention will be described with reference to Figures 4-5. Figure 4 shows an example of the configuration of a conventional machine tool system using an NC lathe 200, and Figure 5 shows a block diagram illustrating an overview of the machine tool system of the present invention. To demonstrate how the machine tool system of the present invention can utilize the machine tools used in conventional machine tool systems, Figures 4-5 use an NC lathe 200 with the same basic configuration as the NC lathe 100 shown in Figures 2-3. Here, we will describe the lubricant supply flow path in this machine tool system, particularly the configuration that differs from that shown in Figures 2-3. Note that components in Figures 4-5 with the same last two digits and symbols as those in Figures 2-3 have the same components and functions as those in Figures 2-3. Furthermore, arrows in Figure 5 indicate the flow of machining or hydraulic fluid, and the thickness of the arrows represents the magnitude of the flow rate, as in Figure 3.

[0053] In the machine tool system of the present invention, as in the NC lathe device 200, the base of the machining fluid used in the machining of the workpiece 218 by the tool 232 among the lubricating fluids is a water-soluble material as in the past, but in this machine tool system, the base of the working fluid used to lubricate the sliding surface of the tool spindle 220 and the rotating shaft of the turntable 230 is the same water-soluble material (described in detail later) as the working fluid. Also, in the NC lathe device 200, the second storage tank 134b is not provided alongside the first storage tank 234a as in the past.

[0054] First, as for the "machining fluid," a predetermined amount of new machining fluid 236 is initially poured into and stored in a first storage tank 234a, as in the previous example shown in Figures 2 and 3. When the NC lathe device 200 is operated, the machining fluid 236 in the first storage tank 234a is pumped up and discharged through a suction flow path 238 and a discharge port 238a to the machining portion (see Figure 5) near the workpiece 218 and tool 232. The discharged machining fluid 236 lubricates and cools the machining portion, and then falls from the workpiece 218, the rotary table 230, etc., and is received and collected in a collection container (collection means) 240.

[0055] The recovered machining fluid is returned from a discharge port 242a through a discharge flow path 242 downstream of the recovery container 240 to the first storage tank 234a, and is then pumped again into the intake flow path 28 from an intake port 238b located at a predetermined height so as not to pump up sludge 244 that has settled at the bottom, thereby completing a machining fluid reuse and circulation process. Note that this machining fluid (and working fluid, described below) reuse and circulation process may have other flow path configurations as long as there is a recovery and storage means (see FIG. 5) downstream of the used liquid processing section. For example, the recovery container 240 and the first storage tank 234a may be directly connected, or the machining fluid may be temporarily assembled from the recovery container 240 and transported to the first storage tank 234a, as in the previous examples shown in FIGS. 2 and 3. Hereinafter, when machining fluid is initially poured into the first storage tank 134a in the initial state, there is no need to collect and dispose of the oil-soluble components in the second storage tank 134b for two-liquid separation (oil-water separation) as in the conventional machine tool system shown in Figures 2 and 3, and since the total amount of machining fluid in the system is only reduced due to water evaporation, etc., new machining fluid or dilution water is poured in or added only to make up for the reduced amount or when regular maintenance is performed. Below, we will explain why there is no need for a two-liquid separation process for the working fluid and machining fluid, while showing examples of the flow path and components of the hydraulic oil.

[0056] First, regarding the flow path of the "hydraulic fluid," hydraulic fluid is primarily composed of an oil-soluble material, and is generally filled in a closed space. Therefore, when new hydraulic fluid 252 is initially filled into the hydraulic fluid filling tank 250, a small amount of hydraulic fluid leaks out, and the remaining amount is appropriately filled. The hydraulic fluid 252 in the hydraulic fluid filling tank 250 is generally diverted into a first hydraulic fluid supply path 254 on the tool spindle 120 side and a second hydraulic fluid supply path 254 on the rotary table 230 side, and is supplied to the sliding parts of the tool spindle 220 and the rotary table 230 (see FIG. 5), respectively. This hydraulic fluid is supplied to lubricate the sliding parts, and, as described above, is not released in large quantities like hydraulic oil, but a small amount does leak out of the sliding parts. The leaked working fluid 252 falls downward from the tool spindle 226, tool 232, rotary table 230, etc., and much of it reaches the recovery container 240 arranged to recover the machining fluid 236, and the liquid in the recovery container 240 becomes a state in which the working fluid 152 has been mixed into the machining fluid 236.

[0057] However, unlike conventional machine tool systems, the working fluid 152 and the machining fluid 236 both contain the same water-soluble material as their components, and therefore the mixture of the working fluid and the machining fluid recovered in the recovery container 240 reaches the first storage tank 234a via the discharge flow path 242 as a liquid that does not contain oil-soluble components. Therefore, except for the concentration, the working fluid 152 and the machining fluid 236 stored in the first storage tank 234a are of the same quality as the machining fluid initially filled.

[0058] As a result, there is no need for a two-liquid separation process as in the conventional machine tool systems shown in Figures 2 and 3, and as described above, the recovered and stored working fluid 152 and machining fluid 236 can be circulated directly to the machining section and reused. As described above, this is beneficial in various ways. In the example of the machine tool system of the present invention shown in Figures 4 and 5, because sludge 244 that settles in the first storage tank 234a remains, the mixed liquid of working fluid 152 and machining fluid 236 stored in the first storage tank 234a is not reused or circulated as working fluid (see the arrow in Figure 5).

[0059] <<Examples of Compositions of Machining Fluid and Hydraulic Fluid>> The compositions and blending ratios of the hydraulic fluid 152 and the machining fluid 236 that have been verified to be effective in the machine tool system of FIGS. 3 and 4 are shown below.

[0060] The preferred compositions (and blending ratios) of working fluid 252, which is electrolyzed water as a stock solution, and machining fluid 236, shown in (i) to (vi) below, were verified. Note that the first part in parentheses below indicates the "usable blending ratio" and "more preferred blending ratio" for the "stock solution." Since the stock solution is often diluted before use for machining fluids, the preferred blending ratio for that working fluid is shown in the second part in parentheses. Here, the "usable blending ratio" refers to a blending ratio that can satisfy the sliding characteristics and lubricity, even when left unused for a long period of time and undergoes special conditions such as viscosity changes and decay, and the "more preferred blending ratio" refers to a range that reliably satisfies the sliding characteristics and lubricity in an environment where the fluid is normally used in a general manner. (i) amines (5 to 25% by weight, more preferably 10 to 20% by weight, even more preferably 10 to 20% by weight; when used as a processing fluid, less than 10% by weight may be used); (ii) fatty acids (5 to 25% by weight, more preferably 10 to 20% by weight; when used as a processing fluid, less than 10% by weight may be used); (iii) polymers (3 to 50% by weight, more preferably 3 to 15% by weight; when used as a processing fluid, less than 3% by weight may be used); (iv) alkaline electrolytic water (present as a solvent, proportion in the stock solution is 3 to 70% by weight); (v) if added, anticorrosive agent (0.1 to 0.2% by weight); (vi) if added, pH buffer material (0.1 to 0.2% by weight).

[0061] (i) Amines are added to maintain the alkalinity of electrolyzed water and maintain a high pH to prevent it from becoming acidic. pH adjustment will be discussed in the explanation of alkaline electrolyzed water (iv) below.

[0062] However, not all amines are suitable. For example, tertiary amines, such as those found in PS and PX, are susceptible to oxidation, resulting in discoloration and adhesion. They are particularly unsuitable for use as working fluids (lubricants) on sliding surfaces at the interface of castings. For example, ethanolamine, a tertiary amine, is not suitable for use alone or in combination. Furthermore, some secondary amines have been identified as potentially carcinogenic, and as such, secondary amines in general are generally not favored worldwide. Given the widespread use of alkaline electrolyzed water as working fluids for machine tools and machining fluids, these fluids are not necessarily suitable. Based on these considerations, suitable amines for use as working fluids (lubricants) and machining fluids on sliding surfaces include cycloamines, diamines, alkylamines, and glycolamines.

[0063] In addition, (iv) the components of the water to be blended are selected taking into consideration the risk of the alkaline electrolyzed water turning into powder when the water evaporates, and taking this into consideration, the amount of (iv) amines to be added as alkaline agents is preferably in the range of 5-25% by weight, more preferably 10-20% by weight.

[0064] (ii) The fatty acid is blended to ensure lubrication. Generally, fatty acids have 8 to 18 carbon atoms. However, when the fatty acid is used in the hydraulic fluid or machining fluid of the machine tool system of the present invention from the viewpoint of contributing to the promotion of a decarbonized society by making the user aware of its water-solubility visibly and tactilely, it is preferable to avoid raw materials that are solid (powder) as much as possible and to select fatty acids that remain liquid at room temperature. Examples of such fatty acids include fatty acids with 9 to 10 carbon atoms, such as straight-chain saturated fatty acids such as nonanoic acid, decanoic acid, and caprylic acid, straight-chain unsaturated fatty acids such as undecylenic acid, branched saturated fatty acids such as isononanoic acid and versatic acid, and dibasic acids such as sebacic acid.

[0065] Of these, versatic acid has a strong salt exchange effect, so unless the base is carefully selected, there is a risk of separation and metal corrosion, making it not necessarily suitable. Furthermore, from the perspective of rust prevention and stability, linear saturated and unsaturated fatty acids such as nonanoic acid, caprylic acid, and undecylenic acid are preferred, and among branched fatty acids, isononanoic acid is preferred. On the other hand, if transparency after dilution with water is not important, isostearic acid, which has a large carbon number but satisfies all of the liquid properties, rust prevention, and stability requirements, can also be selected and used as a suitable fatty acid. Furthermore, in order to make the (ii) higher fatty acid water-soluble, a salt is formed between (i) an amine and (ii) the higher fatty acid.

[0066] (iii) Polymers are incorporated to ensure the viscosity of the hydraulic fluid and improve lubrication on sliding surfaces. To prevent sliding problems, particularly sluggishness after restarting after shutdown, it is necessary to reduce viscosity changes due to water evaporation. Polymers are therefore required as a compounding component of electrolyzed water used in hydraulic fluids and machining fluids. Suitable examples include polymers and derivatives of (A) ethylene oxide, (B) propylene oxide, or (C) butylene oxide, as well as copolymers of any two of (A) to (C) and derivatives thereof. Among these, for example, polyalkylene glycols preferably have an average molecular weight in the range of 400 to 4500. One of these polyalkylene glycols contains nitrogen atoms in its structure for rust prevention of sliding components, primarily made of iron-based materials, in machine tools. The other preferably contains butylene glycol, which acts as a lubricant in machining fluids. The average molecular weight of butylene glycol is preferably 400 to 500.

[0067] As described above, this machine tool system is a circulation system in which the stock solution of alkaline electrolyzed water is added to the working fluid used as a lubricant for the sliding parts of the machine tool, the stock solution is diluted with water when initially filled with machining fluid, and the two are used again as machining fluid after recovery. (iv) The alkaline electrolyzed water is alkaline water containing potassium hydroxide obtained using potassium carbonate as an electrolyte, for example, and when this alkaline electrolyzed water is initially added as working fluid, the viscosity is ensured by the above-mentioned polymer and the amount mixed into the machining fluid is very small, so in that sense a strong alkali with a pH of 10.0 to 12.5 is considered to be no problem, but considering the impact on non-ferrous metal materials around the machine tool, a pH of <10.0 is preferable for the stock solution added as working fluid.

[0068] Furthermore, if the material being machined is a non-ferrous metal, a high pH may cause corrosion, so it is preferable to dilute and adjust the machining fluid to a weak alkali, at least pH ≤ 9.0, so as not to place any restrictions on the workpiece being machined.

[0069] The hydraulic fluid and machining fluid do not contain preservatives, but may contain (v) an anticorrosive agent, such as one suitable for non-ferrous metals such as copper, zinc, and aluminum. (vi) Silicone-based antifoaming agents are used. Both are added as desired depending on the material of the machine tool and the composition of the above (i) to (iv).

[0070] As described above, it has been verified that when the hydraulic fluid and machining fluid containing the above-mentioned water-soluble material are used in the horizontal NC lathe device 10 of FIG. 1 and the vertical NC lathe device 200 of FIG. 3 as examples of the machine tool system of the present invention (FIGS. 4 and 5), the continued operation is suitable.

[0071] Therefore, it will be understood by those skilled in the art that, according to the machine tool system of the present invention, the hydraulic fluid and the machining fluid for the machine tool can both be water-soluble materials that do not contain oil-soluble materials derived from mineral oil, and the machining fluid can be reused and circulated without separating into two liquids. Note that the embodiment shown in this specification and the drawings is one example of the present invention, and it will be obvious to those skilled in the art that various other improvements and modifications exist based on the concept and teachings of the claims.

[0072] REFERENCE SIGNS LIST 10 Horizontal NC lathe device 100, 200 Vertical NC lathe device 12 Frame 14 Spindle (C1 axis) 16 Spindle (C2 axis) 18, 118, 218 Workpiece 20, 120, 220 Tool spindle 22 Lower bed 24 Upper bed 26, 126 Headstock 130, 230 Rotary table 123, 232 Tool 134 Storage tank 134a, 234a First storage tank (discharge container) 134b Second storage tank 136, 236 Machining fluid 138, 238 Intake flow path 138a, 238a Discharge port 138b, 238b Intake port 140, 240 Recovery container (recovery means) 142 Discharge flow path 142a Discharge port 143 Waste flow path 144, 244 Sludge 146 Waste flow path 150, 250 Hydraulic fluid filling tank 151, 251 Sliding portion 152, 252 Hydraulic fluid 154, 254 First hydraulic fluid supply path 156, 256 Second hydraulic fluid supply path

Claims

1. A machine tool system that operates a machine tool in an environment where a working fluid used for lubricating the machine tool and a processing fluid used for processing a workpiece are mixed, wherein electrolytic water that does not contain oil-soluble materials derived from minerals is used for both the working fluid and the processing fluid, the working fluid and the processing fluid are mixed and recovered as they are after the lubrication function has ended, and are returned to the processing fluid and / or working fluid supply path for circulating, and the electrolytic water is alkaline electrolytic water containing at least amines, fatty acids, and polymers.

2. The machine tool system according to claim 1, characterized in that the alkaline electrolyzed water contains 3-70% by weight of alkaline electrolyzed water as a solvent in the original solution, and contains 5-25% by weight of amines, 5-25% by weight of fatty acids, and 3-50% by weight of polymers as solutes in the original solution.

3. The machine tool system according to claim 1, characterized in that the alkaline electrolyzed water is blended in its original solution with 10% by weight to 20% by weight of the amines, 10% by weight to 20% by weight of the fatty acids, and 3% by weight to 15% by weight of the polymers.

4. The machine tool system according to claim 1, characterized in that, when the alkaline electrolyzed water is used as a machining fluid, it is blended with 20% by weight or less of the amines, 20% by weight or less of the fatty acids, and 15% by weight or less of the polymers.

5. A machine tool system as claimed in any one of claims 1 to 4, characterized in that it comprises: a recovery means arranged downstream of the lubrication flow path of the machine tool for mixing and recovering the working fluid and machining fluid after the lubrication function has ended; a discharge container connected to said recovery means for storing the working fluid and machining fluid; and a circulation means for drawing the working fluid and machining fluid in the discharge container as they are from an inlet arranged at a position away from the bottom without oil-water separation, and returning them to the supply oil path for the machining fluid and / or working fluid.

6. The machine tool system according to any one of claims 1 to 5, characterized in that the amines are cycloamines, diamines, alkylamines, or glycolamines.

7. A machine tool system according to any one of claims 1 to 5, characterized in that the fatty acid is nonanoic acid, caprylic acid, undecylenic acid, isononanoic acid, or isostearic acid.

8. A machine tool system according to any one of claims 1 to 5, characterized in that the polymer is a polymer of ethylene oxide (A), propylene oxide (B) or butylene oxide (C) and its derivatives, or a copolymer of any two of (A), (B) and (C) and its derivatives.

9. A machine tool system according to any one of claims 1 to 5, characterized in that the alkaline electrolyzed water is a raw solution fed as a working fluid with a pH of < 10.0, and the machining fluid is circulated after being adjusted to at least a pH of ≦ 9.

0.

10. A machine tool system according to any one of claims 1 to 5, characterized in that the alkaline electrolyzed water does not contain any preservatives and contains a pH buffer.

11. A machine tool system as claimed in any one of claims 1 to 10, characterized in that the supply oil passage through which the circulating means returns the hydraulic fluid and machining fluid from within the discharge container is a machining oil supply oil passage, and communication to the hydraulic oil supply oil passage is blocked.

12. The machine tool system according to any one of claims 1 to 11, characterized in that it has a lathe function, a milling function, a grinding function, a drilling function, or a sawing function for machining a workpiece.

13. Electrolyzed water for machine tools used as a working fluid for lubricating machine tools and as a processing fluid for processing workpieces, characterized in that the electrolyzed water for machine tools is alkaline electrolyzed water containing at least amines, fatty acids, and polymers.

14. The electrolytic water for machine tools according to claim 13, characterized in that the amines are cycloamines, diamines, alkylamines, or glycolamines.

15. The electrolytic water for machine tools according to claim 13, characterized in that the fatty acid is nonanoic acid, caprylic acid, undecylenic acid, isononanoic acid, or isostearic acid.

16. The electrolytic water for machine tools according to claim 13, characterized in that the polymer is polyalkylene glycol or butylene glycol.

17. The electrolytic water for machine tools according to claim 13, characterized in that the original alkaline electrolytic water has a pH of less than 10.0.

Images