WO2014081281A2 - Lubrication system in cnc machine linear guide ways for precise machining and less oil consumption - Google Patents

Abstract

The present invention relates to a lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption. The system includes: a) at least four thermocouples Tcpl_A, Tcpl_B, Tcpl_C, Tcpl_C embedded in linear guide of X-axis and Z- axis of CNC machine for temperature measurement; b) lubrication unit for discharging accurate amounts of oil or lubricant at predetermined intervals; c) lubrication control unit (LCU) with several modules for electrical circuit system; and d) program software for facilitating data acquisition, digital or analog input/output, data analysis, and for monitoring output of the lubrication system; wherein the lubrication system is capable of simultaneously monitoring real time current and temperature of the machine.

Description

LUBRICATION SYSTEM IN CNC MACHINE LINEAR GUIDE WAYS FOR PRECISE MACHINING AND LESS OIL CONSUMPTION

FIELD OF INVENTION

The present invention relates generally to a lubrication system, and more particularly to an intelligent lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption. BACKGROUND OF INVENTION

Friction occurs in all mechanical systems such as transmissions, valves, piston rings, bearings, machines, etc. It is well known that journal bearings, friction also occurs in all lubrication regimes. However, shaft misalignment in rotating system is one of the most common causes of wear and tear. In many engineering system, when two surfaces slide against one another, friction is a nuisance. Friction in engineering system has two undesirable effects, i.e. it increases wear and tear, and adds work which is not useful (energy loss). Accordingly, wear is the progressively damage involving material loss, which occurs on the surface of a component as a consequence of its motion (friction) relative to the adjacent working parts; and friction between two surfaces converts kinetic energy into thermal energy, or heat.

In recent times there have been rapid changes in the way of machine to perceive lubrication as new technologies have become accessible to skills in the arts whose care about the consumption of lubricant. Carriage movement which allows movement of filing tools for vector machining operations is of great importance on the table of CNC machines. It is to be noted that there will always be wear and corrosion of parts between two pieces of frictions and temperature stimulus, thus manufactures are of great interested in lubrication system, particularly to facilitate the lubrication system for more precise machining and less oil consumption which takes better ways to progress.

In many cases, accuracy and precision of CNC turning machines are affected due to variety of errors. The errors are combined (superposed) resulting in final irregularities on surface of work piece. Some errors occur during cutting operation or caused by process operation, and some other errors may already exist before cutting. The increasing requirements for precision of spindle rotation on metal-cutting machine tools, including the account for thermal deformations, require provision of small heat release in the bearing when operating at substantially high speeds. Thus, problem of rolling-element bearing lubrication on machine-tool spindle arises and being an urgent task. According to the data of FAG (Germany), with the installation of high-precision bearings in in the spindle assemblies of machine tools, the temperature of the spindle bearings should not exceed 50°C - 60°C (temperature rise of 30°C - 40°C), while for the very high-precision machines the temperature should not exceed 30°C - 40°C (temperature rise of 10°C - 20°C).

High-speed spindles and tables in CNC machine tools which are highly related to thermal errors have received significant attention over the past few years. Although thermal errors can be reduced by structural improvements to machine tools, physical limitations still require a compensation system. A temperature raise in a machine structure can start from a few heat sources, the heat from which is then transferred into an individual structure. As a result, the temperature variable may have a strong dependency. The most current research is focused on the thermal error compensation of the whole machine tool. Thermally induced error is a time-dependent nonlinear process cause by non-uniform temperature variation in the machine structure. The interaction between the heat source location, its intensity, thermal expansion coefficient and the machine system configuration crates complex thermal behavior. Researchers have employed various techniques such as finite element methods, coordinate transformation methods, neural networks etc., for modeling thermal characteristics.

It is also known that a high-speed drive system generates more heat through friction at contact area, such as the ball screw and the nut, thereby causing thermal expansion, which adversely affects machining accuracy. Thus, the thermal deformation of a ball screw is one of the most important objects to consider for high-accuracy and high-speed machine tools. In order to achieve high precision positioning, preload on the ball screw is necessary to eliminate backlash. Ball screw preload also plays an important role in improving rigidity, noise, accuracy and life of the positioning stage. However, preload produces significant friction between the ball screw and the nut that generates greater heat, leading to large thermal deformation for the ball screw and causing low positioning accuracy. Consequently, the accuracy of the main system, such as a machine tool, is affected.

Although a high-speed feed drive system reduces a non-cutting time and tool replacement time, making production more economical. However, it also generates more heat through friction at contact area, such as the ball screw and guide ways, causing thermal deformation that subsequently degrades the accuracy of the machine tool. Errors that affect the machine tool accuracy are classified as (i) geometric errors, (ii) thermal errors, and (iii) cutting force-induced errors. Among said errors, thermal errors account for 70% of the total errors. Moreover, influences of current may affect the moving parts of servo motors. In order to correct the thermal errors, building a robust thermal error model may require as first step. However, the mechanism causing the machine tool deformations is so complex that it is impractical to theoretically derive an analytical expression as the thermal error model by use of all initial conditions and operating conditions for a machine tool. As far as most modeling methods are concerned, the thermal error models are all achieved by finding the best mapping relations between the thermal error model and some thermal key points' temperature changes.

Numerical computation is another branch on studying machine tools' thermal deformations. Accordingly, structural design of headstocks of precision lathes was optimized based on the computation results with finite element method in reference, investigated thermal-bending behavior of the spindle simplified as a simple beam. Slide guide have been widely used for precision motion applications due to their high load- bearing capability and high damping property. However, because slide guide dynamic friction properties vary with external load, speed, and running time, it has become necessary to monitor and compensate for these effects to achieve precision motion. Furthermore, in order to maintain a high degree of reliable accuracy over long period of operation, it is of paramount importance that an appropriate control model of the slide guide is established in terms of preload, wear, and operation conditions. Also, the motion errors due to thermal distortion have to be properly predicted and compensated on-line. A suitable lubrication can reduce friction and hence, energy consumption. Suitable lubrication can further reduce wear and prevent seizure, and hence can extend the life of a machine and save natural resources. In fact, the effect of lubrication is usually far more remarkable in reducing wear than in reducing friction. Conventionally, two methods are used for lubrication of carriages in CNC machines, i.e. (i) manual lubrication, and (ii) automatic lubrication. Manual and automatic lubrication methods are used independently or together based on the design provided by the machine makers.

In view of these and other shortcomings of the existing know-how, it would be useful and advantageous to provide an intelligent lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption.

SUMMARY OF THE INVENTION

The present invention relates to an intelligent lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption. In this project and research study, the lubrication system as an alternative intelligent method is proposed for CNC machines. A systematic approach in lubrication, introducing new control techniques and intelligent optimum quantities of lubrication in CNC machine has been deliberated. The premeditated of lubrication system in CNC machine mainly examines thermal effect in the carriage and current effects in server motors, and presents compensation schemes for friction in two different positioning systems with precision accuracy requirements.

Accordingly, the lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption, the system includes: a) at least four thermocouples Tcpl_A, Tcpl_B, Tcplc, Tcpl_c embedded in linear guide of X-axis and Z-axis of CNC machine for temperature measurement; b) lubrication unit for discharging accurate amounts of oil or lubricant at predetermined intervals; c) lubrication control unit (LCU) with several modules for electrical circuit system; and d) program software for facilitating data acquisition, digital or analog input/output, data analysis, and for monitoring output of the lubrication system; wherein the lubrication system is capable of simultaneously monitoring real time current and temperature of the machine.

In the preferred embodiment, two thermocouples are disposed at each axis, i.e. the X- axis and Z-axis, for temperature measure of linear guides. Accordingly, the thermocouples are embedded inside two parallel linear guides of each axis. Preferably, the thermocouples Tcp , Tcpl_B, Tcpl_c and Tcpl_D are symmetrically embedded inside the linear guide of the X-axis and Z-axis. Accordingly, the thermocouples are installed on rail guide ways of the Z-axis with predefined distance from edge of chuck. Accordingly, the thermocouples are installed on middle of rail guide ways of the X-axis with predefined distance from spindle axis.

It will be appreciated that sensors are preferably placed between two linear guides nearby the chuck; each sensor is at predefined distance from the thermocouple so that maximum temperature can be sensed. Accordingly, sit place of the sensors at predefined length are used for detecting the maximum range of temperature of the X- axis.

In the preferred embodiment, the thermocouples Tcpl_A and Tcpl_B measure the temperature of Z-axis linear guides, while the thermocouple Tcpl_c and Tcpl_D measure the temperature of X-axis linear guides.

It is to be noted that the thermocouples Tcpl_A, Tcpl_B, Tcpl_c, Tcpl_c detect real time temperature in contact interface between carriage and rail guides and wherein temperature readings are sent to Lubrication Control Unit (LCU) for processing.

In accordance with preferred embodiment of present invention, the predetermined intervals of the lubrication unit for discharging accurate amounts of oil or lubricant can be from several minutes to several hours.

In the preferred embodiment, the lubrication unit is a type of VERSAMATIC III, a self- contained motorized gear pump which is compact and efficient. Accordingly, the lubrication unit is complete with a built-in level switch, pressure switch, built-in controller or external controller.

The lubrication unit further includes motor-driven gear pump with a built-in flow control valve. Accordingly, the flow control valve relieves distribution line pressure during "OFF" period.

It will be appreciated that the lubrication unit further includes a pressure switch and low- level switch to monitor occurrences of pump cycle and low oil levels in reservoir. The lubricator unit may further include a built-in timer to control the operating cycles of the lubricator.

In the preferred embodiment, the reservoir includes three different capacities i.e. 2 liters, 3 liters or 4 liters and the reservoir is made of materials such as ABS or metal.

In the preferred embodiment, the electrical circuit system connects four major parts, i.e. sensors, measurement modules, test controller and actuators. Accordingly, the electrical circuit system provides signals which are sent from thermocouples and current clamp to universal measurement module; and this module processes temperature errors and current variable from servo motors that arrives in the test controller.

It will be appreciated that the module of the preferred embodiment is a programmed micro controller for controlling data input from the sensors and to send output to the actuators. In accordance with preferred embodiment of the present invention, the lubrication control unit (LCU) is equipped with modules and test controller to acquire and analyze data with a default supplier testing program. Accordingly, the LCU sends necessary signals to the actuators and monitoring unit, and wherein the LCU can be adjusted to some default setup. Preferably, the default setup includes operation sensors' limits, type of sensors to be used, color and type of curve to be displayed in monitoring unit. It will be appreciated that the test controller is a programmable module with flash data memory that offers a graphically programmable PAC function. Accordingly, the test controller includes interfaces for modules connection. The modules connection can connect up to 16 modules to each of the four serial interfaces (UARTs) of the test controller.

In the preferred system, the modules include universal measurement module and temperature measurement module.

Accordingly, the universal measurement module is a modular data acquisition system offering flexible approach to each application, said module is used independently for exploiting features and functionality, or used in combination with a test controller.

Accordingly, the temperature measurement module includes at least eight electrically isolated analog inputs for thermocouples or voltages.

In the preferred embodiment, the test controller is communicated with program software and universal measurement module. Preferably, the program software is real time software for data collection, signals capturing, data monitoring and analysis. Accordingly, the program software used in the system is Nl Lab VIEW V.11 or above and this software package is comfortable tool to configure either in the online or offline mode.

It will be appreciated that the system is suitable for manual mode, semi-programmed mode and fully programmed mode machineries.

The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying description and drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, wherein:

FIG. 1 shows an X-Axis servo motor of a CNC machine in accordance with preferred embodiment of present invention; FIG. 2 shows a Z-Axis servo motor of the CNC machine according to preferred embodiment of the present invention;

FIG. 3 shows a belt tightener with holders of the CNC machine according to preferred embodiment of the present invention;

FIG. 4 shows a carriage joint for connecting to lubrication pipe of the CNC machine according to preferred embodiment of the present invention;

FIG. 5 shows a special Current monitor model Pearson, which fixed on the wires of servo motor drivers X and Z-Axes.

FIG. 6 shows a flow control valve for oil pressure of hydraulic pump according to preferred embodiment of the present invention; FIG. 7 shows sensors installation according to preferred embodiment of the present invention; FIG. 8 shows configuration of oil pipes at Z-axis and X-axis supporters in accordance with preferred embodiment of the present invention;

FIG. 9 shows modules of Lubrication Control Unit LCU configured at electrical box in accordance with preferred embodiment of the present invention;

FIG. 10 is a lubrication unit (VERSAMATIC III) according to preferred embodiment of the present invention; FIG. 11 is a lubrication control unit (LCU) electrical circuit system in accordance with preferred embodiment of the present invention;

FIG. 12 shows a lubrication unit for electrical circuit system according to preferred embodiment of the present invention;

FIG. 13 shows a schematic of the Automated Lubrication system according to preferred embodiment of the present invention;

FIG. 14 shows a pin assignment for Universal Measurement Module A101 according to preferred embodiment of the present invention;

FIG. 15 shows a measurement of voltage for Universal Measurement Module A101 ;

FIG. 16 shows a measurement of current for Universal Measurement Module A101 ;

FIG. 17 shows a measurement of thermocouple for Universal Measurement Module A101 ; FIG. 18 shows a digital input and output of the Universal Measurement Module A101 ;

FIG. 19 shows a pin assignment for Temperature Measurement Module A104 according to preferred embodiment of the present invention;

FIG. 20 shows a measurement of voltage for the Temperature Measurement Module A104. FIG. 21 shows a measurement of thermocouple for Temperature Measurement Module A 04;

FIG. 22 shows a pin assignment for Digital Measurement Module D101 according to preferred embodiment of the present invention;

FIG. 23 shows a digital input and output of the Digital Measurement Module D 01 ;

FIG. 24 shows a dialog with a force transducer (4-wire) and a current input configuration for sensor parameter setting;

FIG. 25 shows a dialog with a digital input and output configuration for digital inputs/outputs;

FIG. 26 shows a digital with a computation configuration (maximum) according to preferred software of the present invention

FIG. 27 shows a dialog for specifying a time format for system variable; FIG. 28 shows a configuration dialog for a virtual variable; FIG. 29 shows a display of buffer contents with Test Viewer;

FIG. 30 shows a dialog for displaying the variable values;

FIG. 31 shows a dialog displaying the module information; FIG. 32 shows a dialog displaying the status information;

FIG. 33 shows a comparison of temperature variation in X and Z -Axes linear guides for every 30 minute reading when initial temperatures are different in according to one set of experiments Thermocouple Tcpl_A, Tcpl_B, Tcpl_c and Tcpl_D of a fully manual mode;

FIG. 34 shows a comparison of temperature variation at every 30 minute reading when the initial temperatures of Z-Axis is 30.4°C according to another set of experiments Thermocouple Tcpl_A, Tcpl_B, Tcpl_c and Tcpl_D of fully manual mode; FIG. 35 shows a comparison of temperature variation at every 30-minute reading when initial temperatures of X and Z Axes are different and critical temperature is 32°C, for semi-programmed mode;

FIG. 36 shows a thermocouples temperature records in Z-axis direction of guide ways using the Semi-programmed lubrication mode; FIG. 37 shows a comparison of temperature variation at every 30-minute Reading when initial temperature of the X-Axis is 30.2°C and that of the Z-Axis is 30.3°C and critical temperature is 32°C (MRI= 20s), for semi-programmed mode;

FIG. 38 shows a thermocouples temperature records in X-axis direction of guide ways using the Semi-programmed lubrication mode;

FIG. 39 shows values indicate the temperature alarm is ON "1", where Tcpl_D = Tcr, for fully programmed mode;

FIG. 40 shows a real time temperature variation for X and Z Axes (for third time Tcpl_D = Tcr), and Enlargment of ineffectual variation;

FIG. 41 shows a Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 10 s;

FIG. 42 shows a view values indicate that Temp Alarm is ON "1" while pump operation is OFF "0";

FIG. 43 shows a Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 15 s; FIG. 44 shows values indicate for the third time, the temperature alarm is OFF "0";

FIG. 45 shows a Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 20 s; FIG. 46 shows values indicate that oil injection occurred for the second time since pump operation = "1";

FIG. 47 shows a Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 25 s;

FIG. 48 shows values indicate the second time after oil Injection;

FIG. 49 shows comparison of temperature variation in X and Z Axes linear guides, after 7:42:52 hours CNC machining for MRI= 25s;

FIG. 50 shows comparison of temperature variation in X and Z Axes linear guides, after 7:40:58 hours CNC Machining for MRI=15s;

FIG. 51 shows a circuit of adjustable resistor (potentiometer) for the system;

FIG. 52 shows a current variation in time interval;

FIG. 53 shows values indicate the motor alarm is OFF "0";

FIG. 54 shows values Indicate the motor alarm is ON "1";

FIG. 55 shows current variation at 2hrs:48min: 09s;

FIG. 56 shows a temperature variation of (a) Z, and (b) X-Axes Linear Guides; FIG. 57 shows a temperature variation of (a) Z, and (b) X-Axes Linear Guides in different condition;

FIG. 58 shows a temperature variation of (a) Z, and (b) X-Axes Linear Guides in another different condition;

FIG. 59 shows a temperature variation of (a) Z, and (b) X-Axes Linear Guides in still another different condition; FIG. 60 shows a temperature variation of (a) Z, and (b) X-Axes Linear Guides in yet another different condition;

FIG. 61 shows real time temperature variation for X and Z-Axes (Tcpl_A,B,c,D < Tcr); FIG. 62 shows values indicate the temperature Alarm is OFF'O";

FIG. 63 shows a real time temperature variation for X and Z-Axes (for second time Tcpl_D = Tcr); FIG. 64 shows values indicate for second time, the temperature alarm is ON "1"

FIG. 65 shows a real time temperature variation for X and Z-Axes (for third time TD = Tcr); FIG. 66 shows values Indicate for third time the temperature alarm is OFF "0"; FIG. 67 shows comparison of real time temperature variation between two axes, and the critical temperature was 33°C (MRI = 10s);

FIG. 68 shows a real time temperature variation for X and Z-Axes after about 7hrs and 42min, that is lower than Tcr, where after the Machine is turned off.

FIG. 69 shows a real time temperature variation for X and Z-Axes MRI= 25s (Tcpl_D = Tcr); FIG. 70 shows a real time temperature variation for X and Z-Axes MRI= 25s (for second time Tcp = Tcr);

FIG. 71 shows a behavior of the fully automated lubrication mode and the oil consumption levels at different MRIs during the entire of the working time;

FIG. 72 shows a real time current variation after 7 hours and 47 minutes, MRI=25s; FIG. 73 shows values indicate the motor alarm is ON "1";

FIG. 74 shows comparison of oil consumption for MRI=10, 15, 20 and 25s;

FIG. 75 shows comparison of oil Consumption for PSOQL and ordinary modes of operation when MRI= 10s and 15s. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an intelligent lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption. Hereinafter, this specification will describe the present invention according to the preferred system of the present invention. However, it is to be understood that limiting the description to the preferred system of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the scope of the appended claims.

The present invention generally involves a project which is undertaken to contribute to the development of an intelligent lubrication system in CNC machine liner guide ways for more precise machining and less oil consumption. The following are objectives for the research: a) To design and analyze a lubrication control unit and electric circuit system design using Computer Aided Design (CAD) and Solid Work software;

b) To fabricate a lubrication system and to modify the CNC machine using Computer Numerical Control (CNC) milling machine;

c) To evaluate the intelligent lubrication system performance with special software (Nl LabVIEW V11) and to test commander on a computer desktop.

Generally, the process of this research includes three stages, i.e. a) Disassembly; b) Edit and Embed; and c) Assembly. It will be appreciated that before operating of the intelligent imbrication system in CNC machine linear guide ways for more precise machining and less oil consumption, any relevant experiments on base's machining accuracy on various material workpieces should be done. The preliminary studies are to be done by researchers and data collections as well as analysis have to be investigated. It is to be noted that in order to control the lubrication system in a CNC machine, National instrument and LabVIEW V11 are preferably used. The characteristic of the software, necessary equipment, inter-relationship, control and data monitoring will be described herein after in the description. The significant stage is the design and installation of the lubrication system on the machine.

Before any editing and embedding the circuit and respective sensors to any existing machine design, it is a necessity to disassemble certain movable metal parts and rotary axis of the machine. Accordingly, certain machine parts such as chip cover, cable chain, limit switches, X and Z axis servomotors (FIGS. 1 and 2), X-axis servomotor, couplings, bearings, X-axis ball screws, table support mounting, X-axis liner guide, Z-axis supporter, Z-axis liner guide, Z-axis ball screw, beltings, bearings of spindle axis belt tightener (FIG. 3), coupling, chuck, spindle axis, spindle cell have to be removed for easy access and installation.

It will be appreciated that for installation of the lubrication system and embedding sensors, some machines such as Electrical Discharge Machining (EDM), CNC milling machine, manual milling machine, manual turning, radial drill press, dressing machine, general mechanical machinery may be used. Appropriate instruments are important for effective installation which can reduce time and cost. It will also be appreciated that before any mechanical change to the work piece and machine, computer-designed of work piece is primary applied. Preferably, the changes are applied to the work piece separately for reliable results finding before the changes are applied to the machine. Accordingly, the preferred computer-designed software such as solid work 2009 is used. By way of example, but not limitation, individual part of design changes may include follows:

1. Making a first 5-path from aluminium for distributing main channel to:

a) Secondary 5-path

b) Z-axis ball screw

c) Z-axis carriage lubricating pipe

2. Making a secondary 5-path from aluminium for distributing lubricating pipe from first 5-path's junction to:

a) X-axis ball screw

b) X-axis carriages

3. Making special X-axis carriage joints for connecting to the lubrication pipes (FIG. 4)

4. Making holes for:

a) Tapping over the spindle axis shell and brush between the bearings to create an inlet oil path

b) tapping below the spindle axis shell and brush between the bearings to create an oil bypass

5. Making appropriate holes on machine body for pitching the pump and reservoir

6. Making mould and special tool from copper to spark machining (EDM) on liner guider (FIG. 5)

7. Grooving on X and Z - axis's linear guides with EDM to predetermined depth for thermocouples installation

8. Creating holes on worktable and on sitting place of linear guides to the spindle for passing wire of thermocouples

9. Making hole in the nut of Z-axis ball screw for passing oil pipe

10. Chip removal from all parts before machining 11. Making hole for tapping under Z-axis supporter to attach joints of carriage and ball screw lubrication pipes

12. Making hole on the Z-axis supporter and on the sitting place of X-axis liner guides at their middle for passing thermocouple wire

13. Creating holes for tapping on the Z-axis supporter for pitching the first five-path

14. Making holes and tapping place of thermocouple wire on the Z-axis supporter

15. Making hole for tapping on the supporter for lubrication pipe installation between the first and second five-paths.

16. Machining with CNC milling machine on the X-axis supporter for:

a) attaching the second five-path

b) passing the lubrication pipes and brass joints

17. Making hole on X-axis supporter for passing the ball screw lubrication pipe

18. Chip removal from all parts before machining the X-axis supporter. In the assembly process, the assembly requires to accomplish sliding, as well as install the lubrication circuit and brass joints simultaneously. This stage is important because any lack of precision, accuracy of machinery and attention to pitch parts of machines may result in decreasing work pieces life and lead to incorrect operation. By way of example, but not limitation, the assembly of parts may include:

1. Attaching oil pump and reservoir to machine body

2. Attaching outer spindle cell, spindle axis, chuck eccentric on spindle axis, chuck on spindle

3. Installing and modifying belt lightener holder on outer shell of the spindle

4. Installing the belt in pulleys of servo spindle and spindle axis

5. Putting belt lightener's bearing and attaching fixer screws in suitable traction

6. Attaching junctions and following control of hydraulic pump pressure (FIG. 6) 7. Attaching the lubrication couple pipe from spindle to oil pump three path and passing from a predefined way

8. Installing Z-axis carriage in linear guides

9. Attaching junction of lubrication on the Z-axis carriage

10. Passing thermocouple wire from the table holes in extension of linear guide's axis

1 1. Installing liner guile correctly, with attention to location of the thermocouples and attaching the linear guide's screws

12. Installing ball screw inside the nut and Z-axis ball screw's body

13. Putting ball screw with its nut on true location and attaching the coupling, bearing and holders between the servomotor and ball screw

14. Attaching the Z-axis servomotor

15. Installing the ball screw's middle oil pipe and attaching the carriage pipes behind the Z-axis supporter with four junction pieces

16. Putting Z-axis supporter in body of ball screw's nut and attaching screws

17. Attaching first 5-path to the wall of Z-axis supporter

18. Installing joining oil pipes to the carriage and Z-axis ball screw via special junctions to the first 5-path

19. Passing the thermocouple wires from the holes made on the Z-axis supporter in the extension of sitting place of X-axis liner guides (FIG. 7)

20. Correct installation of liner guides, with attention to thermocouple locations

21. Attaching converter joints before machining to connect to X-axis carriage pipes

22. Installing X-axis carriage on the linear guides

23. Attaching the second 5-path on the X-axis supporter and simultaneously installing all oil pipes inside the grooves

24. Installing the X-axis supporter on the carriage

25. Attaching the oil pipes on the X-axis supporter and connecting to the carriage 26. Accomplish sliding and test of move metal test of X-axis supporter on the linear guides for confiding to the correct and easy movement without skip/slip

27. Attaching the oil pipe between the first and second 5-paths on the body of Z-axis supporter and connecting its head and end (FIG. 8)

28. Attaching the nut of ball screw to internal part of the X-axis supporter

29. Installing the head and end of the X-axis ball screw bearings and straddles between servomotor and X-axis ball screw

30. Attaching the X-axis servomotor to the stand

31. Passing all cables of X-axis servomotor and wiring harness of limit switches from cable chain

31. Passing the wires of thermocouple from the cable chain after restraining them on the body via some joints

32. Selecting suitable place for installing modules and controlling inside of electrical box (FIG. 9)

33. Connecting the wires of thermocouples to universal modules after passing those from the body to the inside part of the electrical box

34. Attaching two brackets of cable chain in the machine body and X-axis servomotor stand

35. Attaching hose of oil main way to the first path on the Z-axis supporter

36. Attaching the wires of limit switches according to design

37 Providing 220V electricity for connecting to adaptor to convert and direct 12V of electricity

38. Turning on CNC machine and testing Installation Process of Sensors

A suitable place for embedding thermocouple on the CNC machine is investigated. Accordingly, one point between the carriages is chosen. Attention to be paid to parameters such as number of thermocouples, load of parts weight, length of work piece and amount of feed rate especially when pickup becomes the places for embedding the thermocouples. In the preferred embodiment, at least four thermocouples are used. Preferably, chromel and alumel of stainless steel are used. It is to be noted that two thermocouples are preferably used for each axis, i.e. the X and Z axis, for temperature measure of linear guides. The thermocouple is embedded inside two parallel linear guides of each axis. Data collection on the heat transfer from each carriage is to be analyzed so that appreciates location for thermocouples installation is defined.

By way of example but not limitation, the installed thermocouples on rail guide ways of the Z-axis have a distance 0.15m (150mm) from edge of chuck. Sensors are preferably placed between two linear guides nearby the chuck. It will be appreciated that each sensor is preferably of 0.06m (60mm) from the thermocouple so that maximum temperature can be sensed.

The thermocouples installed on X-axis are used in middle of rail guide ways where the thermocouples are preferably embedded about 0.2m (200mm) distance from spindle axis. It will be appreciated that maximum diameter of work piece, which can be machined by the CNC, is preferably 0.06m (60mm). Thus, sit place of the sensors (L = 60mm) is suitable for detecting the maximum range of temperature (FIG. 7).

On the Z-axis (in spindle alignment), the carriages undergo almost 45kg of load. That includes the weights of: supporter, worktable, bearings, holder plans, holder of tools, carriages and linear guides, ball screw axis, etc. On the X-axis (in vertical axis spindle), the carriages undergo almost 21kg of load. That includes weights of: supporter, turret, bearings, holder plans, holder of tools, carriages and linear guides, ball screw axis, etc. All these loads are on the Z-axis. Thus, in summary, 66kg loads are on the Z-axis.

Linear guide is used in the Electrical Discharge Machining (EDM) machine to generate a groove therein. The EDM typically works with materials that are electrically conductive. In order to prevent deformation and bending of the linear guide, the machining time has to be increased by decreasing cutting feed rate. A special tool according to FIG. 5 is to be used before the linear guide is introduced. Preferably, this special tool is molded from copper to spark machining on the linear guide.

Technical Data Sheet for Lubrication Pump

In accordance to preferred embodiment of the present invention, a lubrication unit, such as VERSAMATIC III is used (FIG. 10). Generally, the lubrication unit, VERSAMATIC III, is a self-contained motorized gear pump which is compact and efficient. This type of lubrication unit is suitable for most industrial lubricants from 20cst to 2000cst, and it meets a variety of lubricating requirements.

Accordingly, the VERSA III is programmed to discharge accurate amounts of oil at predetermined intervals from several minutes to several hours. The units are available complete with a built-in level switch, pressure switch, built-in controller (SMAC / SM-B1) or external controller. There are three different capacities for the reservoir: 2 liters, 3 liters and 4 liters, and made of materials such as ABS or metal. It will be appreciated that the VERSA III can also be used in PDI system and SLR system. Applications for the VERSA III include: machine tools, plastic machinery and textile machinery, printing machinery, elevator and conveyor equipment.

The VERSA III lubricator unit generally includes a motor-driven gear pump with a built-in flow control valve. The flow control valve relieves distribution line pressure during the "OFF" period, as required for PDI systems. A pressure switch and low-level switch are provided at the VERSA III lubricator unit to monitor occurrences of pump cycle and low oil levels in the reservoir. The VERSA III lubricator unit further includes a built-in timer to control the operating cycles of the lubricator. Accordingly, three modes are required to operate the lubricator, i.e. "Pause" period (pump motor off), "Pressure build" period and "Pressure hold" period. At the end of Pause period, power is supplied to the lubricator's electric motor, commencing Pressure Build operation and increasing oil pressure. Once pressure to operate the system is attained, the lubricator's built-in pressure switch closes, advancing the controller to Pressure Hold mode. The pump motor continues to run until the Pressure hold time is completed. Then the controller advances to the Pause mode and remains in this mode for the preset interval. The controller shuts off the pump allowing the lubricator's pressure dump valve assembly to relieve pressure from the system network, and allows all injectors to reset for the next cycle.

Electrical Circuit System

In the preferred embodiment, an Electrical circuit intelligent lubrication connects four major parts, i.e. sensors, measurement modules, test controller and actuators. Accordingly, signals are sent from thermocouples and current clamp to the universal measurement module and this module processes temperature errors and current variable from servo motors that arrives in the test control. The lubrication control unit (LCU) Electrical Circuit System is shown in FIG. 11.

It will be appreciated that the lubricator unit with a motor-driven gear pump of reasonable structure, excellent performance, complete function, wide applicability, good self-absorption and high volume efficiency. Reservoir capacity for the lubricator unit is preferably 2 liters. The motor-driven gear pump of the lubricator unit is preferably equipped with a level switch and pressure switch that can be employed according to different applications (FIG. 12).

In the preferred embodiment of the present invention, the lubrication control unit (LCU) includes several modules. Each module is a micro controller which has already been programmed for data input from the sensors and to send output to the actuators. Accordingly, the lubrication control unit (LCU) is equipped with modules and a test controller to acquire and analyze data with a default supplier testing program. The LCU sends the necessary signals to the actuators and monitoring unit. However, the LCU can be adjusted to some default setup such as the operation sensors' limits, the type of sensors to be used, and also the color and type of curve displayed in the monitoring unit.

It will be appreciated that the modules have been developed for industrial measurement and testing technology, in particular, for multi-channel measurements of electrical, mechanical and thermal signals on engine and component test-rigs as well as for monitoring processes and long-term supervision.

The individual modules can be combined to form one system as required. It will appreciated that user can connect 32 or 64 modules to one of the Test Controllers and then address them, from a PC or PLC via a single interface. Alternatively, it is also possible to address single modules directly via the serial interface and on all modules the power supply, the bus interface and the inputs and outputs are electrically isolated from one another. Test controller is a programmable module with its own 128 megabyte flash data memory, and in addition it offers a graphically programmable PAC function.

Optionally, Ether CAT is available as an additional interface with a data rate of up to 10 KHz. We can connect up to 16 modules to each of the four serial interfaces (UARTs) of the test controller. We can connect the modules directly to a PC or PLC via the RS-485 interface on the modules.

In the preferred embodiment, a socket is used for supplying power to the module, for synchronization and for the transfer of data. The module is also electrically connected to the top-hat rail (35mm, DIN rail according to DIN EN 50022) through a metal spring in the socket. In addition, user can activate the terminating resistances for the interface at the end of the connection lines, save the module configuration in the socket and restore this configuration when inserting a new module.

For the power supply, an unregulated DC voltage between 10 and 30 volts is required, which is connected to contacts 5 and 6 from above the socket. Each module requires a power of approximately 2W in addition to the power supplied for the connected transducers. The power required is almost constant over the complete voltage range. FIG. 13 shows a schematic of the Automated Lubrication system according to preferred embodiment of the present invention;

Modules and their Connection Options The user can use the modules in the system for specific purposes. The following table (Table 1) gives an overview of A/D Converter Module specifications: types of sensors which can be connected, signal outputs, the number of input channels, maximum data rate in the module and the multiplexer connection options.

Table 1 : A/D Converter Module specifications

Universal Measurement Module (A101 )

The universal measurement module is a modular data acquisition system offering a very flexible approach to each application. Modules can be used independently, exploiting their own features and functionality, or used in combination with a test controller. Accordingly, the universal measurement module has two electrically isolated analog inputs and two digital inputs or outputs. The pin assignment of the two connector strips is identical and the connection terminals have numbers for identifying the connections (FIG. 14). With voltage measurements two connection variants are possible, depending on the level of voltage to be measured, up to 10V and up to 60V (FIG. 15). A shunt resistance of 50 Ω is integrated into universal measurement module A101 for current measurement. This facilitates the measurement of currents of up to 25mA. For higher currents use a voltage measurement with an external shunt (FIG. 16). For connecting thermocouples, a special connecting plug is required. Accordingly, the connecting plug requires comparative measuring point (cold junction compensation) for thermocouples. By way of example but not limitation, the connecting plug can be obtained under the designation Q.bloxx Terminal CJC-A101 from Gantner Instruments Test & Measurement GmbH (Fig 3.20). The user can connect the following types of thermocouple i.e. B, E, J, K, L, N, R, S, T and U. Alternatively, the user can also use two thermocouples or a reference temperature source (FIG. 17).

In is to be noted that on each connecting plug a contact is available for an input or output (FIG. 18). The can use the appropriate function depending on the wiring. The digital input is active (high level) when the applied signal voltage lies above the threshold of 10V.

Temperature Measurement Module (A104)

A temperature measurement module has eight electrically isolated analog inputs for thermocouples or voltages. A pin assignment of the two connector strips is identical and the connection terminals have numbers for identifying the connections. If several connections are possible, the user may find the associated ones in each case at the same place in the circuit diagrams, for example, the figures quoted in the second place belong in each case to one possible connection method. FIG. 19 shows the pin assignment for the temperature measurement module A104.

According to the preferred embodiment, the user can measure voltages of up to 80mV. Voltages which exceed the permissible limits may produce incorrect measurement data as the inputs are protected against over-voltages and limit the input voltage. FIG. 20 shows a measurement of voltage for the temperature measurement module A104. For connecting thermocouples, the user requires a special connecting plug which contains the comparative measuring point (cold junction compensation) for thermocouples. By way of example but not limitation, the connecting plug can be obtained under the designation module Terminal CJC-A104 from Gantner Instruments Test & Measurement GmbH. The user can connect the following types of thermocouple, i.e. B, E, J, K, L, N, R, S, T and U. Alternatively, the user can also use two thermocouples or a reference temperature source (FIG. 21).

Digital Measurement Module (D101)

A digital measurement module has eight digital inputs and eight digital outputs. Accordingly, a pin assignment of the two connector strips is identical and the connection terminals have numbers for identifying the connections. If several connections are possible, the user may find the associated ones in each case at the same place in the circuit diagrams, for example, the figures quoted in the second place belong in each case to one possible connection method. The digital measurement module is preferably connected to the existing test controller system to cater for digital output control. Data exchange between the test controller and automation levels is communicated via Ethernet connection. FIG. 22 shows the pin assignment for the digital measurement module D101.

In is to be noted that on each connecting plug contact for four inputs and four outputs are available. Since the inputs and outputs of this module are electrically isolated from the power supply voltage, The user requires connect the ground (0V, GND) for the inputs and the ground and a supply voltage (+V) for the outputs. FIG. 23 shows a digital input and output of the Digital Measurement Module D101. Accordingly, the digital input is active (high level) when the applied signal voltage lies above the (programmable) threshold. Test Controller

It should be noted that a test controller is communicate well with a software and universal measurement module. However, this system does not provide real programming such as PLC, as real time software is already a powerful tool for data collection, and all signals can be captured or monitored and analyzed in this software.

Generally, the test controller has been designed for demanding measurements found in today's most industrial measuring and testing environments. The range of applications starts from single stand-alone-solutions up to networked multi channeled applications in the field of component testing, engine testing, and process performance testing and structural monitoring.

The range and flexibility of the modules allow an optimized solution for each single task: dynamic signal acquisition of up to 100kHz, in/outputs for all types of signals, galvanic isolation of in/outputs, multi-channel solutions, high density packaging and intelligent signal conditioning.

In the preferred system, data exchange between the test controller and automation levels is being realized via Ethernet TCP/IP or field bus systems such as, for Example, EtherCAT, Profibus-DP or CANopen and additional Ethernet based industrial standards.

To facilitate data acquisition, digital or analog input/output, data analysis, and also for monitoring output for the Intelligent lubrication system, special software is required. Preferably but not limited to, software such as Nl LabVIEW V11 or above is to be used. This software package is a comfortable tool to configure either in the online or offline mode. For test application, several numbers of analog and digital inputs and outputs are required. For all these signals, the invention provides different kind of modules, which will be connected to a test controller i.e. the interfaced between all the sensor signals via the modules and an automation system to speed up the data transmission and to define testing procedures. Depending on the requirements for such a testing application the modules as well as the test controller had to be configured. This configuration can preferably be done with test.commander software in comfortable way.

Accordingly, the test.commander software itself includes the module configuration software ICP100 and the visualization tool Test Viewer. The advantage is that all the modules can be configured in the same way as without test.commander, all user experience of configuration can be used further on.

Configuration of the Software

For the configuration of each connected measurement and I/O module, the software ICP 100 is preferably implemented in test.commander. By clicking on a module or a variable of a module, of which configuration has to be changed the ICP 100 configuration software starts automatically as soon as the test.commander is started. The ICP 100 will run in the background and there is no need to start this software package separately.

A project also contains the hardware setup, the sensor and I/O settings present in the modules as well as the sensor signals used and computations, the so-called variables, which are to be output. Setting Sensor Parameters

In order to set parameters the sensors should be connected to the module and have called the configuration program (ICP 100 which is started automatically by test.commander). Mark a module and select from the context menu Configuration or double click on a module or module signal (variable) to start the configuration program. Then carry out all the module settings in the window of this program. The user can, however, also configure a project without a direct connection and then, once user has established the connection, load the corresponding files into the modules and load Test Controller. All module signals are defined as variables. Therefore, for the entry activate the tab Variable Settings in the configuration program. FIG. 24 shows a dialog with a force transducer (4-wire) and a current input configuration for sensor parameter setting. Specifying Digital Inputs/Outputs

In order to set parameters digital inputs/outputs should be connected to the module and have called the configuration program (ICP 100 which is started automatically by test.commander). Mark a module and select from the context menu Configuration or double click on a module or module signal (variable) to start the configuration program. Then carry out all the module settings in the window of this program. The user can, however, also configure a project without a direct connection and then, once we have established the connection, load the corresponding files into the modules and load Test Controller. All module signals are defined as variables. Therefore, for the entry activate the tab Variable Settings in the configuration program. FIG. 25 shows a dialog with a digital input and output configuration for digital inputs/outputs.

Defining Computations

In order to set parameters for computation, it should be connected to the module and have called the configuration program (ICP 100 which is started automatically by test.commander). Mark a module and select Configuration from the context menu or double click on a module or module signal (variable) to start the configuration program. Then carry out all the module settings in the window of this program. The user can, however, also configure a project without a direct connection and then, once user has established the connection, load the corresponding files into the modules and load Test Controller. All module signals are defined as variables. Therefore, for the entry activate the tab Variable Settings in the configuration program. FIG. 26 shows a digital with a computation configuration (maximum).

System Variable

The software enables the user to specify any format for time signature that is to be recorded: Context menu for system variables Add Variable > ABSDATETIME. After double-click on the variable and a further click on Formula, user can also select other formats (FIG. 27).

With virtual variables, the user can carry out computations, evaluate trigger conditions or carry out assessments. The variables can be output such as measurements, or linked to other variables, measurements or digital l/Os. In the context menu select Add Variable > ARITHMETIC _ EMPTY. After double-click on the variable user can either specify a formula for the computation, define an event which is to be monitored (trigger) or specify the data format to be used (FIG. 28). Online Tools, Displaying Measurements

i) Read Data Buffer

To read the logged data from the data buffer, select File > Read Online Buffer from Controller to read all measured values from the ring buffer and display them graphically. FIG. 29 shows a display of buffer contents with Test Viewer. The user may also use the menu or the icons to set further parameters, to show the channel list, view spectra or to start a live-stream with measured data. The test.viewer provides helpful features such as different measurement zoom functions, many scaling and design tools, etc. It is possible to start test.viewer from test.commander and show the buffer file, or to use test. viewer as a separate tool to show a lot of different types of data such as wav files, etc. The file, stored with test.viewer, can be visualized with the freeware Green Eye Reader, available on our homepage and on our CD, so anybody can work with the recorded data for free. Send the data, including Green Eye Reader, per e-mail and the addressed person can work with these data. ii) Display Measured Values

To open the window with the online asset values, the user may select File > Read Online Values from Controller to view the values of variables. If the user has defined appropriate variables, the user can also set initial values in this dialog. FIG. 30 shows a dialog for displaying the variable values. iii) Read Module Information

To open the window with the Module Information, the user may select File > Read Online Slaves Info from Controller to view information like address or serial number of our system. FIG. 31 shows a dialog displaying the module information. iv) Read Status Information

The information is available with the selection of File > Read Online State Info from Controller to view status information of our system. FIG. 32 shows a dialog displaying the status information.

Experimental Results

In this project and research study, all tests were carried out on a prototype CNC lathe machine. Preferably, scale CNC lathe of 2.0m ^χ 1.0m ^χ 1.5m with a worktable length of 0.8m is examined. Accordingly, maximum Z-axis interval that is available for machinery is restricted to 0.4m by limit switches; and maximum diameter of the cylindrical work pieces is 0.06m. It will be appreciated that the prototype lathe machine was designed for educational purposes. However, the intelligent lubrication system in CNC machine linear guide ways was fabricated and implemented for the machine.

It will also be appreciated that implementing Intelligent lubrication system to the educational lathe machine is considered to improve the learning concepts of machinery with CNC systems. Accordingly, two main variables were considered in the research, including temperature of linear guides on X and Z axes and current in servo-motors for Z-axis. Temperature in X and Z axes were measured by four thermocouples, i.e. Tcpl_A, Tcpl_B, Tcplc and Tcpl_D). Type of thermocouples used is thermocouple K. Tcpl_A and Tcpl_B measure the temperature of Z-axis linear guides, while Tcpl_c and Tcpl_D measure the temperature of X-axis linear guides. The thermocouples are embedded inside the linear guides to detect real time temperature in contact interface between the carriage and the rail guides. The temperature readings are sent to Lubrication Control Unit (LCU) for processing.

The real time Z-axis servo-motor current was measured to control the power load on the motor due to the friction/lubrication process. The measurement is done by a current Monitor Model 2877 fixed on the wire of the motor to detect output current. The result is sent to LCU for processing.

Temperature and current changes by time were measured to control the quality of the CNC performance and command for the optimum required lubricant using a certain program developed for this purpose. It is required to input a critical temperature (Tcr) and critical current (lcr) to the program (Nl LabVIEW V1 1) according to the climate and mode of the machinery. The Tcr and lcr, are determined and can be changed by the operator or user. The program is then takes over the control of the system during machining and sends commands to increase or decrease the lubricant injection into the system.

The real time, measured temperatures and the current are reported in digital numbers and displayed in graphs on the screen of the computer connected to the system via the RS-485 interface on the Modules as described above. Accordingly, the operator or user can observe the changes and the values of measured quantities.

It will be appreciated that presented data can show the influence of the applied load, speed, friction, and other parameters on the machining process of CNC. Parameter monitoring is useful for research study as well as for industrial performance analysis. The parameter provides information about possible unexpected happenings. The mode of the monitored quantities is selected by the operator or user. It is possible to observe one or more measured quantities at the same time on the screen. This fact allows the operator or user to compare the data for the optimum working mode. The operator or user can regulate the injection time of the pump, although the ordinary injection time of the pump was fixed at 10 seconds. However, the Pause-time period can be flexibly selected by operating a DIPswitch in the controller as previously described. It will be appreciated that the pause-time can be adjusted from 1 to 255 minutes. However, fixed injection time (10s) is not desirable for the Intelligent system purpose. Therefore, some changes in the network were made to obtain adjustable injection time. The changes facilitated injection time selection and pause-time simultaneously. The injection time is called Motor Response Interval (MRI) in this work. The MRI was adjusted preferably to 10s, 15s, 20s and 25s. Therefore, the number of variables was increased and included the MRI. On the other hand, the variables are temperature, current, and MRI. The combination of related data about temperature, current and MRI gives the complete picture of machining and intelligent lubrication during machining. Accordingly, the data of these parameters was collected in three modes:

. Fully Manual mode

2. Semi-programmed mode

3. Fully programmed mode

The results of the investigation on the three modes confirmed the reliability, and validity of the collected data. The data collected in this research is shown hereinafter. 1. Fully Manual Mode Experimental Results

The fully manual mode refers to the condition when the lubrication system is off. These experiments were performed to evaluate repeatability of the experiments for temperature increase under similar conditions. In these modes two initial conditions are considered. The conditions related to the initial temperatures shown by the four thermocouples. In a set of experiments Thermocouple Tcpl_A, Tcpl_B, Tcpl_c and Tcpl_D were different. The results of this case are shown in FIG. 33.

In another set of experiments Tcpl_A=Tcpl_B and Tcpl_c = Tcpl_D at the initial time. FIG. 34 shows the results of this case. The temperature reading was carried out every 30 minutes. The figures show the same behavior of temperature growth within 210 minutes with different rates. In all figures the Tcpl_A, B centered on the Z-axis, and Tcpl_c, D centered on the X-axis. The thermocouples can report temperature changes of each linear guide's lubrication to the control unit. The heat source operating temperature changes in linear guides are going and back movement supporters, and the weight of the burden of them. This creates friction force between the carriages, and linear guides are being generated. To say of course is necessary due to changes in ambient temperature influences the sensitivity of thermocouples on the top has been measured.

Initial temperature for each of the thermocouples is different and after 210 minutes the temperature reached 33°C. Each curve of the thermocouples has a gentle slope. We investigate in the next chapter the thermo changes for each of the X, and Z-axes.

Accordingly, the X and Z-axes' thermocouples below the two axes at the two initial tests are at common temperature. Raise in temperature is well coordinated. Temperature changes in FIG. 34 shows continuous temperature growth with time.

2. Semi-programmed Mode Experimental Results

Semi-programmed mode refers to sets of experiments when critical temperatures of Tcr and MRI are considered in the experiments. In a set of experiments Tcr = 32°C and MRI = 10s (FIG. 35 and 36). In these figures initial temperatures of thermocouples are different. The temperature reading was performed every 30 minutes. The figures show that the temperature increase rate changed near the critical temperature and declined later. The decline of temperature is observed just after an interval of time from the time when the temperature reached critical temperature. Therefore, the injection of lubricant into the system cooled down the machine after a short delay, and hence the curves include a maximum. In order to investigate the influence of MRI on cooling rate and machine response another set of experiments were carried out. In this set, the time of injection was considered to be MRI=20s. The initial temperature of the Z-axis was 30.3°C while the temperature of the X-axis was 30.2°C, and the critical temperature was 32°C (Tcr = 32°C). The results are shown in FIG. 37. The figure shows that the cooling rate increased and delay time after reaching to the critical temperature shortened.

3. Fully Programmed Experimental Results

Fully programmed mode refers to the experiments carried out under the control of the program test.commander. The program monitors the four temperatures measured by Tcpl_A, Tcpl_B, Tcplc and Tcpl_D. If one or more of the readings reach the given critical temperature (Tcr), the Temp Alarm indicates "ON=1" that shows the injection order is sent to LCU for lubrication. The lubricant will be injected for an interval of particular MRI, once only, until the next time one of the temperatures reaches Tcr again. On the other hand, the program is set to detect the stability of the alarmed temperature under the Tcr to be T=Tcr - 0.2. During this time interval, the LCU is not allowed to inject lubricant, unless the temperature reaches Tcr for the second time. Temp Alarm ="0" indicates that temperatures have not reached the given Tcr, OFF state. If Pump Operation indicates "0", that means there is no injection, or OFF state. While indicating "1" means the injection system is operating, or ON state. The indicator is on "0" or " only for the duration equal to the given MRI.

FIG. 38 shows shows a thermocouples temperature records in X-axis direction of guide ways using the Semi-programmed lubrication mode. Tcpl_c measured the temperature that reached Tcr =32°C at this particular time. The values of time and temperature are indicated in the figure. The related View values are presented in FIG. 39. The figure shows TempAlarm ="1" and Pump Operation ="1". This means that reaching Tcr = 33°C was detected by the program, and the program has sent a signal to LCU to turn the injection "ON'. MRI = 15s was considered in this experiment. In the graph of each Tcpl, some fluctuations are observed that are related to accidental events such as on/off switching of CNC, tool changer replacement, modifying the process, etc. These events are quite ordinary and occur frequently in CNC machining. FIG. 40 shows a real time temperature variation for X and Z Axes (for third time Tcpl_D = Tcr). As can be seen in the graph shown in FIG. 41 , a Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 10 s

In FIG. 42, the view values indicate that Temp Alarm is ON "1" while alarm is activated "1", but the pump function is turned off "0". This is because MRI = 15s, but the real time is t = 20s after the injection. Generally, if the MRI is set on 15s, then after Temp Alarm "ON" condition appears, the LCU will inject lubricant only for 15s. After this particular time (15s), although Temp Alarm still is "ON", the Pump Operation is "OFF". This situation will continue constantly until the temperature falls to T = Tcr - 0.2 C. Once again, if the temperature rises to Tcr = 33°C the LCU will operate again only for 15s. This scenario will be repeated every time. In other words, when the Temp Alarm is "ON" the LCU operates the injection for the duration of given MRI defined by the operator. FIG. 43 shows that the Temperature Variation in X and Z Axes Linear Guide ways, After 460 minutes Machining for MRI= 15 s. Temperature was measured half an hour after the machine was turned off. FIG. 44 shows values indicate for the third time, the temperature alarm is OFF "0". The results for MRI =20, and 25s are presented in FIGS. 45, 46, 47, and 48. The temperature-time values indicate that Temp Alarm was ON" twice about t = 2:42 and t = 6:38. The Pump goes ON" for the duration of MRI = 25s, and then goes "OFF".

In another set of experiments MRI=25s was considered for machining. FIG. 49 shows that Temp Alarm went "ON" only twice within about 7 hours and 42 minutes. Each time, LCU injected oil to the CNC for the duration of MRI = 25s. Since the injection rate is constant, 108ml/min, the amount of oil injected to the machine twice (2 ^χ 25 = 50s) is more than that of oil injected for three times if MRI = 15s (FIG. 50). Therefore, the oil consumption when MRI = 15s is less than that of MRI = 25s.

Experimental Results of Current Control

Another variable considered in the research was the current in Z-axis servo motor. Since the Z-axis is along the spindle axis of the turning machine, it has more transitional movement than the X-axis. The real time Z-axis servo-motor current was measured to control the power load on the motor due to the friction/lubrication process. The measurement is done by a current Monitor Model 2877, fixed on the wire of the motor to detect output current. The result is sent to LCU for processing.

Current control is necessary because it is sensitive to the friction increase in contacts. Therefore, the current of servo motors was selected as a variable to be measured. The changes in current indicate that the mechanical movements are not smooth. The skip- slip motions of carriages and/or supporters cause an increase of current in the servo motors. These undesirable mechanical movements of the parts, in a short time, result in damage to the sliding surfaces. In the long term, the non-smooth displacements of parts result in decreased precision of machining. Therefore, detecting real time current is required to have on time information about the conditions of the machining process. The detection of existing problems in machining is done by current clamp monitor. Then the signals are sent to the LCU to command relay for oil injection.

The servo motor current increases only if some difficulties in mechanical movements occur. In this case, the condition may affect damages to the machine. Therefore, it is necessary to simulate the problem and study the interaction between current clamp and the LCU in controlling the required oil in the machining process. Obviously, detection of any mechanical problem requires more lubricant to facilitate smooth movements. In this research, a variable resistor and/or a potentiometer was used to cause current changes flowing into the LCU. The resistance is installed between current clamp and LCU (as shown in FIG. 9). FIG. 51 shows adjustable resistor (potentiometer) for the system.

It is required to define a critical current (lcr) for a fully- programmed mode experiment. The servo motor maximum current under unload conditions machining is 0.4A. The lcr = 0.5A was set for this mode. For any other conditions, it is required to measure the maximum current, and then define an according critical current. This can be done by the program test.commander. If the current exceeds lcr = 0.5A, a signal is sent to the LCU for oil injection into the machine. It is necessary to mention that the problems related to mechanical movements seldom happen to cause changes in the servo motor current. However, it is inevitable in the machining process and occurs if there is a severe problem in the mechanical parts movements. Therefore, these problems need serious and urgent attention. Once the current changes are detected by the program and command of injection is sent to the LCU, the process of injection will continue until the current drops to lcr = 0.5A. FIGS. 52 and 53 show real time current variation in serious experiments, where these current variations were simulated by the potentiometer.

FIGS. 54 and 55 indicate real time current values of experiment, Pump Operation, and Motor Alarm. In this moment in time of pump operation, lubrication is generated for 20sec. because the current is more than the critical current.

Data Analysis

Experimental data shows that when the environment temperature of linear guides achieves critical level grade, the LCU sends a command to the oil pump to trigger a relay. Time of the lubrication or motor response interval (MRI) was measured via various tests so that the injection of oil is cut off as soon as temperature and/or current reach a given critical value. Considering the various experiment setups, the time changed from 10 to 25 seconds until finally in the best condition, which was 15 seconds, it was fixed. Meanwhile, the amount of different environmental temperature conditions was tested repeatedly to ensure reliability of the results. The present invention of the lubrication system was set to operate at critical temperatures of 32, 33 and 34 degrees. The best temperature to stabilize the situation in the current environment was considered Tcr = 33°C. This temperature can be changed flexibly by the changes applied to the program.

Accordingly, the defined critical temperature is selected based on the following factors: a. Hard rate of work piece

b. Amount of feed rate load

c. Type of insert (cutting tools)

d. Time of oil injection.

1. Fully Manual Results Analysis The graph in FIG. 56(a) (and also refer to FIG. 33) shows the two curves of temperature variation for Z-axis increase in the temperature variation of the experiment time in 210 minutes. In general, both temperatures increased up to around 32.5°C at which point, there was not a reduction in temperature due to retrenchment. In initial time, the Tcpl_A was almost 30.7°C. During the initial time, the temperature initiated to increase slowly, with some fluctuations, by just over 0.3°C. Then during 60 minutes, from an operation of lath machine, the temperature underwent a rapid increase after 150 minutes. From 150 to 210 minutes there was a gradual increase in the temperature of Tcpl_A. Finally, this temperature reached nearly 33°C.

Generally, it can be seen that 210 minutes after turning the CNC machine on, operation thermal effects happened on the linear motion of carriages. After that we can define the critical temperature for each one of the thermocouples, independently. In this figure, another curve of thermocouple Tcpl_B shows that it almost follows the curve of temperature variation of thermocouple Tcpl_A with lower, not significant variations.

According to FIG. 56(b), the temperature variation of Tcpl_c, D for X-axis is investigated. From initial time, there was an upward trend in the temperature, and it reached a peak at 32.55°C. From initial time up to 210 minutes after that the result had a likeness of both Tcplc, D- From 90 minutes until the end, there was a moderate increase in temperature at Tcpl_D, rather than Tcpl_c. Both these curves are created close to each other, and it shows that temperature variation for X-axis linear guides are not different.

In general, with reference to FIG. 33, to compare temperature variations on X-axis and Z-axis linear guides, when the initial time is different it can be said there is an upward linear trend in the temperature variation for Tcpl_D. Position of this thermocouple is on the X-axis, and it is the nearest to the spindle axis. The graphs in FIG. 57(a) present information on the temperature variations in linear motions of the machine in different conditions to the last experiment. In this test, there is a common initial temperature Tcpl_A, _»■ Temperature of thermocouples at the initial time was 30.4°C. 210 minutes after the lath machine operation where there was neither lubrication operation nor cooling on the axes, the temperature increased by almost 2°C. Meanwhile it can be seen that some fluctuations, but in general it has gradual increase. After three hours Tcpl_A reached almost 32°C. In this time Tcpl_B reading was about 31.5°C. This temperature difference, which has been observed from initial time in both thermocouples, is due to the Tcpl_B which has been embedded on the linear guide far from the spindle axis. Therefore, it has fewer loads than Tcpl_A. That is why there is a slight upward trend in the temperature variation at Tcpl_B.

According to FIG. 57(b), in the first 60 minutes the temperatures of Tcpl_c, D had a rapid increase, and they were similar. Meanwhile, they both had 29.4°C at initial time. From 90 minutes (when Tcpl_D reached 31 °C) machining until the end, increasing temperature rate was slow until the temperature reached about 32°C.

It can be clearly seen that temperature variation has an upward trend, and there might be some insignificant fluctuations.

2. Semi-programmed Results Analysis

Semi-programmed mode refers to sets of experiments when critical temperatures of Tcr and MRI are considered in the experiments. FIGS. 58(a) to 60(b), discussed in this section present the details of semi-programmed experimental data. According to the graphs in FIG. 58(a), temperature increase rates in Tcpl_{Ai B}fell after reaching the critical point. Tcpl_Aj B had a temperature of about 30°C before machining. In 90 minutes, there was a slight upward trend in temperature variation. From this time to 150 minutes the temperature increased dramatically. During this time, when the temperature of Tcpl_A reached the critical point or critical temperature (Tcr), LCU injected oil for 10 seconds. Almost 30 minutes from oil injection the temperature increase rate went down. Then, after 180 minutes the temperature decreased. This means there is a delay time between the injection process and decreasing temperature to below Tcr = 32°C. This curve shows a good selection of critical temperature for intelligent lubrication after 2°C from initial time, because a significant upward trend for temperature has been shown. In this figure there is another curve which shows the temperature variation of Tcpl_B. Its Initial temperature is less than Tcpl_Al and never reached the critical temperature because at 31.5°C the lubrication process affected Tcpl_B. The behavior of this curve is very similar to Tcpl_A.

FIG. 58(b) shows temperature variation of X-axis thermocouples. At the initial time of the experiment, both thermocouples had a temperature of about 30°C. There was a rapid linear upward trend for both Tcpl_c, _D- There was still an increase in temperature 30 minutes after the injection of oil, and it reached 32°C after 180 minutes. However, although in LCU the temperature alarm was ON "1", no oil injection occurred again. Lubrication at the time of almost 120 minutes brought on a downward trend in these thermocouples.

Generally, there are some fluctuations at temperature variation before the critical temperature (Tcr = 32°C). However, after the critical temperature and oil injection, an orderly downward trend in temperature is obtained.

It can be clearly seen in FIG. 59(a), that the temperature dropped almost 30 minutes after reaching the critical point, Tcr = 33°C. In initial time of experiments in all thermocouples temperature was equal to 31.7°C. From this time until 90 minutes, the temperature curve shows almost a sharp increase. According FIG. 59(b), because the thermocouple reached the critical temperature earlier than the other thermocouples, the 90 minute timeout oil injection operation was done. Motor response interval time for the oil injection by LCU was MRI = 10s. Tcpl_A, B still did not reach Tcr = 33°C, but operated under the influence of lubrication, so there was a reduction in the rate of temperature rise. At 120 minutes the temperature of Tcp reached 33°C. Because the TempAlarm was still "ON", there was no more oil injection. However, afterwards the temperature in Tcpl_A declined and ultimately reached 32.5°C at 210 minutes. There is the same fluctuation in another curve (Tcpl_B) which is slightly different from the Tcpl_A. So between the times of 120 minutes and 150 minutes the temperature of TcplC was fixed at 32.9°C. Then a decreasing trend occurred quickly.

FIG. 59(b) presents the temperature changes on the X-axis, and the trend of temperature change is uniform. It can be seen that up until the temperature reached critical point TCr = 33°C, a sharp upward trend without fluctuations was observed. At 90 minutes of machining when the Tcpl_D reached critical temperature (Tcr = 33°C), the LCU began oil injection. MRI = 10s for X-axis thermocouples is not enough to have an influence on the linear guide temperature. Thus, as can be seen for Tcpl_c, D it took approximately 60 minutes to bring a downward trend in temperature.

Overall, considering FIG. 36, at critical temperature 33°C for the amount of oil injection, 10 seconds for cooling and controlling the heat in the X-axis linear guides are not sufficient. In other words, in order for the system reaction to be able to control the thermal error, longer time should be considered for oil inject (MRI >10s). The graphs in FIG. 60(a) present longer oil injection time or in other words, the length of the motor response time (MRI) has a direct effect on the rate of temperature reduction. As can be seen in FIG. 60(a), this MRI = 20s was selected as lubrication timeout. That is why the curve for all the thermocouples, which indicates temperature variations, has major differences from previous experiments. Tcpl_A, B in initial time had the same temperature of 31.6^°C. 90 minutes after the initial operation of CNC lathe machine, Tcpl_A had an increase in temperature by 1.2^°C, while temperature in Tcpl_B increased about 0.6^°C. As previously described Tcpl_A, B mounted on the Z-axis. Since Tcpl_A is close to the spindle axis, there is a difference between Tcpl_A and Tcpl_B thermodynamically. So the temperature increase observed is doubled, because there is the burden of too much weight moving axes on the carriages of linear guides. In addition, a desktop milling machine under a 30 degree angle will increase the resultant force on the carriages. It has been proven through previous experiments and the curves confirm it.

However, at thermal exposure time of 90 minutes in FIG. 60(b), Tcpl_D reached critical temperature (Tcr = 33°C) earlier than other thermocouples. The temperature was already brought to the system program. From this moment onwards the LCU sent a message for oil injection for a period of MRI = 20s to the oil pump. Approximately 30 minutes after the oil injection the temperature continued to rise, but with a slighter slope. Oil injection effect on the cooling system was observed 120 minutes later. It can be seen that a faster decrease in temperature in the system. The diagram of both thermocouple curves did not achieve critical temperature, but they were affected by Intelligent lubrication system.

According to FIG. 60(b), the initial temperatures of Tcpl_c, _D were 31.7^°C. There was an upward trend, similar to Tcp , B- AS shown in FIG. 60(b), Tcpl_D reached critical temperature (Tcr = 33°C) earlier than other thermocouples. The thermocouple was installed on the X-axis and since the length of the axis is less than Z-axis, the X-axis linear guides have lower heat transfer. In addition, they have more localized heat; therefore according to the figure generated thermal energy is higher. In general, Tcpl_c, D had temperature variations very close to each other, so their curves are similar. The highest temperature at this time is related to the Tcpl_D, which has reached 33.TC. It means only after critical temperature is just 0.1 ^°C above the Tcr = 33°C, the cooling process can be observed. 3. Fully Programmed Results Analysis

The Fully programmed experiments were carried out to modify the real time variables such as critical temperature, MRI, Temp Alarm, and Pump Operation. Furthermore, in this mode the operator can control all variables in Nl LabVIEW V11 or above program, and their real values are indicated in View Values page of the test.commander program.

Tcpl_D, reached the critical temperature of 33^°C after almost five hours for the second time. Therefore, the temperature alarm signal was sent to the lubrication control unit (LCU) to start the pump and send oil to the drive axis for MRI = 15s. According to FIG. 61 , Tcpl_D is on the X-axis and is closer to the spindle axis, so temperature variation rate was greater than the rest. Tool holder and cutting tools are closer than other thermocouples to this thermocouple; therefore, load as well as the tool holder and cutting tool are the main reasons for these changes. Another thermocouple with similar curves was embedded on the X-axis. If compare X-axis thermocouples with Z-axis thermocouples, it can be observed that more temperature variation on the X-axis. It means the linear guides temperatures decreased rapidly after the lubrication operation. X-axis temperature increased during machining and there was more friction on the X-axis. Thermal stress around the embedded thermocouples was due to improper positioning, as well as a short length of linear guides on the X-axis resulted in more temperature changes. FIG. 62 shows values indicate the temperature Alarm is OFF'O";

Values in FIGS. 63 and 64 indicate the Temperature Alarm is ON "1" for the second time. The lubrication system can control the temperature on the moving X and Z-axes, according to FIG. 65, after about 7 hours and 30 minutes. The process of reducing the temperature at each time can be seen on each curve. So when the critical temperature for this test has been defined (Tcr = 33°C), there is no signal from the lubrication control unit and the oil pump is in the off mode.

The graph in FIG. 65 shows that at the end of all curves the slope for the reduction of temperature gradient is faster. This temperature reduction is due to the lubrication operation and stopping machining after 7 hours.

Values shown in FIG. 66 prove that the temperature alarm and pump function are OFF "0" when the temperature in all thermocouples is less than the critical temperature. Z-axis thermocouples (Tcp , B) and X-axis thermocouples (Tcpl_c, D) values are shown separately in FIG. 67 for comparison.

The total time of experiments was 7 hours and 40 minutes. In this period, the thermocouples reached the critical temperature defined three times. The times were: t1 = 3:27, t2 = 5:09, t3 = 6:34. When the motor response interval was MRI = 15s during the test time (7 hours and 40 minutes), oil injection occurred 3 times (FIG. 68). In this process the amount of oil consumption is 45s * 108ml/min = 81 ml. The injection of oil by the intelligent lubrication system to the machine was done during 45 seconds in the whole process. According to the oil pump specifications unit volume oil transfer is 108ml/min. Thus, during the 45 seconds, almost 81 ml of oil were sent. While in the same working conditions, if user adjusts the dip switch setting mode corresponding the following mode, at this time 108ml will be consumed. It shows that the present system managed to control the consumption and optimum quantity of oil in a CNC turning machine.

The total time for DIP switch "4, 7 = ON" is 72 minutes (Table 2), while the total time is 462 minutes, therefore the injection process was performed 6 times. Also, MRI = 10s. Results in 60s lubrication means: 60s * 108ml/min = 108ml oil was consumed. It is clear that for MRI = 15s, the oil consumption was 81 ml, but for MRI = 10s it reached 108ml. It means that MRI = 15s can save 27ml of oil in the total process.

Table 2: Setup Pause-time Mode by DIP Switch

The results of these experiments are very important because they are able to achieve three important conclusions. Accordingly, the three primary goals of the research study are as follows: 1. Selecting the appropriate critical temperature for the thermocouples in a workshop environment;

2. Effective setting of Motor Response Interval (MRI); and

3. Reducing oil consumption considerably in comparison with the CNC lathe machine without intelligent lubrication system.

In several tests, the best temperature Tcr determined was 33^°C. Proper selection of Tcr = 33°C can improve accuracy and precision in machining operations. Furthermore, it reduces excess friction that causes wear on moving ingredients like linear guides, carriages, ball screws, etc.

In addition, selecting the appropriate critical temperature causes a soft feed rate without skip-slip of axes. On-time injection of oil and lubrication operation is only possible through selection of correct critical temperature. In addition, the duration of oil injection was measured at 10, 15, 20, and 25 seconds (FIGS. 69, and 70). Some of these tests are given in the research. Finally, the length of response time MRI for this CNC turning machine is designed with the lubrication system.

The graph in FIG. 71 shows a behavior of the fully automated lubrication mode and the oil consumption levels at different MRIs during the entire of the working time.

Oil pump motor response interval was determined to be 15 seconds (MRI = 15s). This time (15s) is not only enough to control the axis temperature, but at least to reduce the consumption of oil in similar machines. In machines with the same oil pump unit but without the system, by the appropriate timer settings and operator needs the lubrication is done. The settings are given in table 2 for setting the pump controller's Dipswitch. Keys Collection is placed in a particular state in accordance with the needs through the machine manufacturer. With every turn on the machine of the first oil injection will start for 10 seconds constantly.

Accordingly, Red LED flashes 10 times as motor runs for 10 seconds. Then green LED turns on and motor stops in Standby mode simultaneously. Each oil injection interval moves buttons to change the Dip switch. This gap is up to 255 minutes. As the RI and pause-time in intelligent lubrication system have been changed, hence the duration of sending oil will be changed through the programming in test-commander software with the tests done. As already mentioned the best calculated time was 15 seconds. In addition, each injection interval in the system is defined. The critical temperature and current variation sensors are determined. It depends on the working condition of the lathe.

Results Analysis of Current Control

The critical current lcr = 0.5A was set in the experiment. A potentiometer was added to set the servo motor current. FIG. 72 shows that the current was less than lcr during 467 minutes except at about t = 25min. At this time, the potentiometer resistance was changed purposely to exceed critical current and observe the injection process. In this experiment MRI = 25s was set, but the oil injection did not follow the MRI time out. This means that as long as the current is greater than lcr = 0.5A, the injection will continue for even more than 25 s until the current falls below the defined critical value. In other words, the MRI = 25s would not stop oil injection unless the current dropped under the critical value. The Motor alarm and Pump operation have the value "1 = ON" in FIG. 73. This means that exceeding the critical current, at the moment I = 0.6A, resulted in Motor Alarm = 1 and consequently the pump injected oil to the CNC machine. The process of oil injection continued until the current dropped below ICr = 0.5A.

Table 3: Lubrication Unit Specifications, where delivery volume is 108 ml/min.

^* The starred cases are not practically realistic because the time is more than total experiment time. According to the values presented in Table 3 Lubrication Unit Specifications, where delivery volume is 108 ml/min. Based on Table 2 the total pause-time mode in accordance with the operating DIPswitch has been calculated. Also the number of pump injections during 7 hours and 40 minutes was calculated. MRI = 10s at self-lubrication mode is fixed. Therefore, the oil injection time during machinery is shown in the table 3.

As an example, for MRI = 10s the oil consumption is 08ml. Selected switches 2, 3, 4, 5, and 6 are "ON". Thus, the total time is 62min and the total processing time is 460min, therefore six injections were performed and consumed 108ml oil in total. The selected mode of the dip switches show the extra need of the CNC machine for oil. Therefore, if we can decrease the period and duration of lubrication according to the need of the machine, we will be successful in achieving optimum oil consumption.

As already mentioned, the variation in the lubrication unit has been generated. Before this MRI was fixed at 10 seconds, but now it is changed to the several modes which all depend on the intelligent lubrication program in the test.commander software. When MRI=15s, the oil consumption will be 81 ml. Minimum oil consumption was observed for MRI = 15s, that being the best mode of lubrication with intelligent lubrication system. Optimum lubrication was observed when MRI = 15s. FIG. 74 presents the difference of oil consumption for MRI = 0, 15, 20, and 25s.

Ordinary machining consumes 108ml oil, while the designed intelligent lubrication reduced the oil consumption to 90ml (FIG. 75). These results show that intelligent lubrication system reduced by 17% when MRI = 10s, and 25% at MRI = 15s oil consumption in 460 minutes of machining.

As a conclusion to this research study as well as to the present invention of the intelligent lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption, the major findings as follows:

1. The intelligent lubrication system was successfully designed, fabricated and applied to an educational CNC turning machine.

2. The designed intelligent lubrication system is capable of simultaneously monitoring real time current and temperature. 3. The thermocouples Tcpl_A, Tcpl_B, Tcpl_c and Tcpl_D were symmetrically embedded inside the linear guide of the X-axis and Z-axis, and resulted in consistent, reliable measurement data.

4. The positions of the thermocouples Tcpl_A, Tcpl_B, Tcpl_c and Tcpl_D were at the most effective points for temperature detection (FIG. 7).

5. Fully manual, semi-programmed and fully programmed results confirmed each other and showed the correctness and effectiveness of the Intelligent lubrication performance.

6. The critical values according to the environmental and/or CNC machine conditions are Tcr = 32°C, TCr = 33°C, lcr = 0.5A, and MRI = 10s, 15s, 20s, and 25s.

7. The optimum oil consumption of intelligent lubrication system has been observed at MRI = 15s. This condition reduced oil consumption by up to 25% compared to ordinary lubrication.

8. Dipswitches have 16 possible options (Table 3). The best option found was No.12.

9. Oil injection has been observed 5 times, 3 times, and 2 times, for MRI = 10s, MRI = 15s, 20s, and MRI = 25s, respectively, for about 467 minutes machining.

It will be appreciated that independent critical temperature sensing alarms for each thermocouple and according injection for each particular axis using an individual oil pipe may be improved the intelligent lubrication system. It is to be noted that after completing injection process, the existing oil in the pipes returns back to the pump. Therefore, if LCU commands for injection again, the returned oil may need some times to move in the pipes and reach to its previous place in the carriages. This means that the interval time needed returning back the oil a gap time between real injection interval and ideal injection pump the motor Response Interval (MRI) function for a few seconds. To improve this process, a check valve or pressure valve may be used. It will be appreciated that the Lubrication Control Unit (LCU) can be simplified by removing the modules. Thus, all the data directly is sent to the controller. On the other hand controller monitors and sends the signals to actuators. Therefore the LCU function can be simplified.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the principle and scope of the invention, and all such modifications as would obvious to one skilled in the art intended to be included within the scope of following claims.

Claims

1. A lubrication system in CNC machine linear guide ways for more precise machining and less oil consumption, the system includes:

a) at least four thermocouples Tcpl_A, Tcpl_B, Tcpl_c, Tcpl_c embedded in linear guide of X-axis and Z-axis of CNC machine for temperature measurement;

b) lubrication unit for discharging accurate amounts of oil or lubricant at predetermined intervals;

c) lubrication control unit (LCU) with several modules for electrical circuit system;

d) program software for facilitating data acquisition, digital or analog input/output, data analysis, and for monitoring output of the lubrication system;

wherein the lubrication system is capable of simultaneously monitoring real time current and temperature of the machine.

2. A lubrication system according to Claim 1 , wherein two thermocouples are disposed at each axis, i.e. the X-axis and Z-axis, for temperature measure of linear guides.

3. A lubrication system according to Claim 2, wherein the thermocouples are embedded inside two parallel linear guides of each axis.

4. A lubrication system according to Claim 3, wherein the thermocouples Tcp , Tcpl_B, Tcplc and Tcpl_D are symmetrically embedded inside the linear guide of the X-axis and Z-axis.

5. A lubrication system according to Claim 4, wherein the thermocouples are installed on rail guide ways of the Z-axis with predefined distance from edge of chuck.

6. A lubrication system according to Claim 4, wherein the thermocouples are installed on middle of rail guide ways of the X-axis with predefined distance from spindle axis.

A lubrication system according to Claim 5, wherein sensors are placed between two linear guides nearby the chuck, each sensor is at predefined distance from the thermocouple so that maximum temperature can be sensed.

A lubrication system according to Claim 6, wherein sit place of the sensors at predefined length are used for detecting the maximum range of temperature of the X-axis.

A lubrication system according to Claims 7 and 8, wherein the thermocouples Tcpl_A and Tcpl_B measure the temperature of Z-axis linear guides, while the thermocouple Tcpl_c and Tcpl_D measure the temperature of X-axis linear guides.

10. A lubrication system according to Claim 9, wherein the thermocouples Tcpl_A, Tcple, Tcplc, Tcplc detect real time temperature in contact interface between carriage and rail guides and wherein temperature readings are sent to Lubrication Control Unit (LCU) for processing.

11. A lubrication system according to Claim 1 , wherein predetermined intervals of the lubrication unit for discharging accurate amounts of oil or lubricant can be from several minutes to several hours.

12. A lubrication system according to Claim 11 , wherein the lubrication unit is a type of VERSAMATIC III, a self-contained motorized gear pump which is compact and efficient.

13. A lubrication system according to Claim 12, wherein the lubrication unit is complete with a built-in level switch, pressure switch, built-in controller or external controller.

14. A lubrication system according to Claim 13, wherein the lubrication unit further includes motor-driven gear pump with a built-in flow control valve.

15. A lubrication system according to Claim 14, wherein the flow control valve relieves distribution line pressure during "OFF" period.

16. A lubrication system according to Claim 13, wherein the lubrication unit further includes a pressure switch and low-level switch to monitor occurrences of pump cycle and low oil levels in reservoir.

17. A lubrication system according to Claim 16, wherein the lubricator unit further includes a built-in timer to control the operating cycles of the lubricator.

18. A lubrication system according to Claim 16, wherein the reservoir includes three different capacities i.e. 2 liters, 3 liters or 4 liters and the reservoir is made of materials such as ABS or metal.

19. A lubrication system according to Claim 1 , wherein the electrical circuit system connects four major parts, i.e. sensors, measurement modules, test controller and actuators.

20. A lubrication system according to Claim 19, wherein the electrical circuit system provides signals which are sent from thermocouples and current clamp to universal measurement module; and this module processes temperature errors and current variable from servo motors that arrives in the test controller.

21. A lubrication system according to Claims 1 and 19, wherein the module is a programmed micro controller for controlling data input from the sensors and to send output to the actuators.

22. A lubrication system according to Claims 1 and 19, wherein the lubrication control unit (LCU) is equipped with modules and test controller to acquire and analyze data with a default supplier testing program.

23. A lubrication system according to Claim 22, wherein the LCU sends necessary signals to the actuators and monitoring unit, and wherein the LCU can be adjusted to some default setup

24. A lubrication system according to Claim 23, wherein the default setup includes operation sensors' limits, type of sensors to be used, color and type of curve to be displayed in monitoring unit.

25. A lubrication system according to Claim 20, wherein the test controller is a programmable module with flash data memory that offers a graphically programmable PAC function.

26. A lubrication system according to Claim 25, wherein the test controller includes interfaces for modules connection.

27. A lubrication system according to Claim 26, wherein the modules connection can connect up to 16 modules to each of the four serial interfaces (UA Ts) of the test controller.

28. A lubrication system according to Claim 27, wherein the modules include universal measurement module and temperature measurement module.

29. A lubrication system according to Claim 28, wherein the universal measurement module is a modular data acquisition system offering flexible approach to each application, said module is used independently for exploiting features and functionality, or used in combination with a test controller.

30. A lubrication system according to Claim 28, wherein the temperature measurement module includes at least eight electrically isolated analog inputs for thermocouples or voltages.

31. A lubrication system according to Claim 27, the test controller is communicated with program software and universal measurement module.

32. A lubrication system according to Claim 1 , wherein the program software is real time software for data collection, signals capturing, data monitoring and analysis.

33. A lubrication system according to Claim 32, wherein the program software used in the system is Nl LabVIEW V11 or above and this software package is comfortable tool to configure either in the online or offline mode.

34. A lubrication system according to Claim 1 , wherein the system is suitable for manual mode, semi-programmed mode and fully programmed mode machineries.