 I welcome you all for the series of lecture on metrology. Now we will start the module number 12. In this module, we will be discussing about advanced metrology. In this module, we will be discussing about the following topics and advanced metrology. We will be discussing about universal measuring machine, coordinate measuring machine. What are the softwares used in CEMs? And then we will move on to laser vision in process aging, stage position metrology. And then we will be discussing about the instrumentations used in nanotechnology. And then we will discuss about the testing and certification services. Finally, we will discuss about complex optomechanical assemblies. Now under module number 12, we will start lecture one. In this lecture, we will be discussing about various aspects of universal measuring machine and coordinate measuring machine. Now in the previous modules, we discussed about various metrological instrumentation like micrometer, linear caliper, dial indicators, protractors, depth gauges, microscope etc. These instruments are used mostly to check one feature of the workpiece. For example, micrometer is used to measure the thickness of the workpiece or the length of the workpiece. And then protractors are used to measure the angle between two surfaces. Similarly, depth gauges are used to measure the depth of holes like this. Now a measuring machine has been devised which can be used to measure the many features of the workpiece in one setting. So this device is known as universal measuring machine. So it is used to quantify inside and outside dimensions like length, diameters and distance between holes. And it can be used to measure angles between the two surfaces of the workpiece. It can also be used to check the thread parameters of inside and outside threads. It can be used to inspect hard workpieces made of hard materials. Or it can also be used to measure the features of soft materials. It is normally used to calibrate all types of standards. For example, blood gauges, ring gauges, thread blood gauges, thread ring gauges, etc. Can be calibrated using this universal measuring machine. Now I can see the pictures of universal measuring machine. We have the base of the measuring machine normally made of cast iron. We can see the guideways. So these are the flat guideway and we inverted the guideway on which the table moves. Now I can see when the table moves in this particular direction, it is moving in the X direction that is longitudinal movement of the table. And when the measuring head moves in this particular direction, it is a transverse direction or movement in the Y direction. And this is the measuring head which can be moved up and down. So this is the vertical travel of the measuring head. We can mount the different probes to the measuring head to carry out the inspection of the workpieces. We can see the objectives through which IPs, IPs through which we can take the readings. And a circular table can be mounted on this table for measurement of features like angles. We can see the hand means to achieve the motion in X, Y and Z direction. Now let us study what are the features of universal measuring machine. A large variety of accessories, supports and probes can be mounted on to the universal measuring machine to check both internal and external features of the workpieces. The measuring force is assured by means of an adjustable gear system which can be regulated to different pressures. So by adjusting the different, by maintaining different pressures, the measuring force can be maintained. So this system eliminates errors which could be caused by veiling the operator field. Because of use of this gear system, the operator field is excluded from the inspection process. Now computer support is available for acquiring processing, logging and transmitting measurement data. The measurement can be made using the probe, different kinds of probes and data is transmitted to the computer system which has a software which will analyze the data and gives the required results. So ESCO-Compliant printout of measurement data is possible. And the different kinds of accessories are available which can be mounted on to the universal measuring machine to assist the inspection of very complex workpieces. The form stability is achieved through a sturdy machine base made of cast iron or granite. And there is high resistance to wear through carbide reinforced measuring surfaces. All the surfaces which are subjected to friction or the wear are covered by carbide reinforced measuring surfaces. CCD camera attachment is also possible. All the moving parts, they have a very good parallel sum within plus or minus one micrometer. And direct display of all measured values is possible. And we have a display of minimum and maximum cold values. We can select the weekly system or metric system depending upon our requirement. And what is the measuring force currently used that also can be displayed because of this arrangement operator field is eliminated. And it is possible to introduce up to nine preset values in the universal measuring machine. The multi-window mode of modes are available on the screen. And then on-screen video help for measuring functions is possible. For example, a particular function is selected. The on-screen help is available so that the operator can use all the functions with much difficulty. On-screen display is also possible. And measurement in absolute comparative mode is possible. Now what are the specifications of these universal measuring machines? So different sizes of universal measuring machines are available in the range of 100 to 500 millimetre and 0 to 1000 millimetre is possible in this x direction movement and in the y direction movement 100 millimetre and in the gel travel 150 millimetre. So like this the universal measuring machines are different sizes are available and resolution can be switched depending upon the accuracy requirement. We can select the appropriate resolution like 1 micrometre or 0.1 micrometre or 100 micrometre like this. Resolutions can be switched and it naturally requires a controlled temperature room for the operation of UMM. And measuring force can be adjusted between 1 to 12 new times depending upon the type of workpiece. And displacement speed of the carriage or the table movement we can select up to 1.5 m per second. Such a high speed is possible. And very fine adjustment range is possible between 0 to 10 millimetre. And then operational temperature limit is from 10 to 40 degrees Celsius and operational humidity limit is 30 to 80%. And repeatability we can achieve up to 0.1 micrometre. The machine weight will be between 80 to 200 kg depending upon the size of the machine. Now various accessories are commercially enviable which can be mounted to universal measuring machine. That is the work table of cast iron is possible or granite is possible. And glass tables are also available which can be mounted onto the machine table. Circular rotary table can be mounted to assist the measurement of angles. And then center supports are available to mount the cylindrical workpieces. And then work folding devices for end measurements are possible. Dividing head they can be mounted and reference plates are available for checking racks. And display unit can be either analog type or digital indicator type. And calling method for elimination from below to measure card tools, radii, whole diameter etc. is possible. Optical system can be attached to the universal measuring machine. And locating microscopes, coniometric microscopes can be attached to the machine to measure angles. Different kinds of probes can be attached. And universal measuring head is also available. Single v support, adjustable v supports can be used. And holders can be mounted for checking the knives or for folding the knives for inspection. And then attachment for measurement between transversal angles is also possible. And lapping equipment also can be used for lapping purpose. And then user friendly software to select testing procedure, resolution and probe time. A set of two prisms can be mounted for measurement of threads. And then calibrated wires can be used for measurement of thread features. Special tool holders can be used depending upon the requirement. And attachment for measuring the picture of internal threads. And microscope for measuring the diameter of internal threads can be attached. And then thread profile heads, taper measurement attachment, all these are possible with universal measuring machine. I can see some of the commercially available universal measuring machines. You can see the base of which the other attachments are mounted. This is the table on which workpiece can be mounted. And the table can be moved in the large tunnel as well as transverse direction. And these spindles are housed in the housing. These housings can be moved in this direction to accommodate the workpieces of different lengths. And then the wheels are provided for moving the table. We can also, distal display is also possible depending upon the moment of the spindle. So, what is the moment can be read out from the distal displays. And then we can see the distal display and the keyboard is also available for setting the preset values. And probes can be attached to the spindles for measurement of internal dimensions. And then you can see here the ID measurement of ring gauge by two probes. That means the ring gauge to be measured is placed on the table as shown here. This is the ring gauge mounted on the table and probes are fixed to these two spindles. By moving the probes, we can check what is the internal diameter of the ring gauge. And similarly, we can measure the outside diameter of the ring gauges. And here, ID measurement of ring gauge using a single probe. So, that we can see and then display it also you can see distal display unit. And OD measurement of plug gauge. So, and here you can see the digital display. So, when we move the probes, what is the amount of movement and the displays on display or the distal display. And finally, we can take out the inspection report using the printers. So, presently universal measuring machines are replaced by coordinate measuring machines. Now, let us move to the discussion on coordinate measuring machine. Under this topic, we will be discussing the following points. What is the need for faster inspection and some basics about coordinate measuring machine? Like what are the different modes of operation of CMM? What are the different configurations available in CMM? And how do we prevent to conduct preventive maintenance of CMM? And then we will discuss about the recent advancement in CMM that is portable CMM and virtual metrology. Now, let us understand what is the need for faster inspection. Now, we have discussed in length about micrometer, one-year calipers, die indicators, protractors, et cetera, et cetera, which are used to measure the various features of workpieces. And these devices, metallurgical devices are used to measure only the single feature of the workpiece. For example, micrometer is used to measure length of the workpiece or thickness of the workpiece, so like that. And for measuring the different features of the workpiece, we need to have a large inventory of instruments, metrological instruments with different ranges, different accuracies, et cetera. So, the metrological instrumentation, the inventory will be too large. And since they have to use different kinds of instruments to measure the various features of the workpiece, the time taken for the inspection of the workpiece is too large. Now, there is a growing need for a device that can do faster, fast-piece inspection and many times 100% dimensional inspection. In view of this, a device is constructed, which is known as co-ordinate measuring machine, which is a sort of advancement in universal measuring machine. So, this co-ordinate measuring machine plays a vital role in the mechanization of the inspection process. We can mechanize the inspection process in a sense. In the production length itself, the CMM can be introduced and as soon as the workpiece is made, it is shifted to the table of CMM and inspection can be carried out. And feedback can be given to the software for making necessary connections with the program if there is any deviation in the workpiece. Now, let us study some basics of CMM. Similar to universal measuring machine, a co-ordinate measuring machine is a device used for measuring the physical geometrical characteristics of an object. This machine may be manually controlled by an operator or it may be a computer-controlled machine. Data collection system is used along with the CMM and data collection system typically includes a machine controller to control the movements of CMM. And there is a desktop computer which has a software to take the data points and to analyze the data points. And after analysis of the data points, it gives the inspection report. Measurements are made by a probe attached to the turret axis of the machine which is known as jet axis of the machine. Now, we can see a stylus attached to the probe head of CMM. So this stylus will move into the hole and it makes contact with the surface of the workpiece and then again it is moved in this direction. And then again the contact is made. Now, when it makes contact with the workpiece at this point, the XYZ coordinates of this particular location is given to the computer. Similarly, XYZ coordinates of this particular location is given to the computer and the software it calculates what is the distance between these two surfaces. Similarly, the diameter of the hole can be found out by making contact at three points and using the data points of the coordinates of these three data points software will calculate what is the location of the center point and then it calculates what is the diameter of the workpiece. Like this, by using the various subroutines, the features of workpiece can be assessed. Now, the probes attached to the CMM may be mechanical type or optical type. By using the mechanical type of probes, measure the various features by making contact with the workpiece surface. In case of optical probe, there is no contact between the optical probe and the workpiece. So it is a non-contact type of measurement. And probes move laterally that is in the X and Y direction, X direction and Y direction. And probe also moves in vertical direction that is Z direction and the data points are recorded. Coordinate measuring machines consist of a platform that is a worktable on which the workpiece being measured is placed. If depending upon the requirement, maybe a fixture is used to mount the workpiece or the workpiece can be directly placed on the worktable for measurement purpose without using any fixture if it is a simple workpiece. Then they are versatile in their capability to record measurement of very complex profiles with high sensitivity and speed. Whenever we need to measure the complex profiles, we can use a scanning type of mechanical probe which will move along the surface and then data points are recorded and then the profile can be evaluated. Now these CMM machines can be placed very close to the machine tool for efficient inspection and rapid feedback for correction of processing parameter before the next part is made. That is workpieces did not be moved to metrology lab. CMMs can be moved to the place where the machine is going. That is CMMs can be installed in the production line itself. As soon as the part is produced, it can be inspected. They are made more rugged to resist environmental effects in manufacturing plants such as temperature variations, vibration and dirt. If temperature variation is there or if there is vibration, automatic compensation is made using necessary software. Now let us see how the CMM looks like. I can see this is the table. It can be a granite table or cast iron table which has a flatness of fraction of a micrometer. And on this table, we can mount the workpiece directly. It can be placed on the worktable surface itself or if necessary, a fixture can be used to mount the workpiece. And then we have two. In this particular configuration, we have two columns. This is column one and column two. These two columns move along the y-axis by using the ball screw and appropriate drives. You can see there is a dust cover to cover the ball screw so that dust will not accumulate on the lead screw. So at this place, column number one will be moving on the granite surface. There will be air jets below this column surface so that it moves frictionlessly. Between these two columns, there is a bridge and this bridge carries the probe head and we can mount the different kinds of probes to this probe head. And this probe head can move vertically up and down the z-axis by using the appropriate drive system. We can move the stylus in the x, y and z direction by operating the joystick. You can see the joystick and various subroutines are available. You can select the subroutines by using this keypad. For example, measurement of diameter of a hole or the angle between two surfaces. Like this appropriate subroutine is selected and then the data points are collected. We can observe a stylus stand here directly mounted on the surface of the granite table. This stylus stand holds the stylus of different sizes and different shapes. Depending upon the inspection requirement, the stylus is selected automatically. It is fixed to the probe head and then measurement is carried out. Now what are the features of a coordinate measuring machine? Now you can observe that a typical CMM is composed of three axes x-axis, y-axis and z-axis. These axes are orthogonal to each other in a typical three-dimensional coordinate system. To give maximum rigidity to the machines without excessive weight all the moving members, that is bridge structure, z-axis carriage and z-columns are made of hollow box construction. Each axis has a scale system, maybe a linear scale or rotary encoders to indicate the location of the particular axis. The machine will read the input from the touch probe or mechanical probe or an optical probe as directed by the operator RCNC program. The machine then uses the XYZ coordinates of each of these points to determine size and position with micrometer precision. Now air bearings are provided for ensuring friction-free travel. In these compressed air is forced through a series of very small holes. For example, we have a granite work table and then the column. In the case of moving column type, column will be moving. So here, air jets will be there. So I will just enlarge this portion, this is the table surface and this is the bottom of column. So here, small holes are provided through which compressed air is allowed to pass. So air will be escaping like this. Because of this arrangement, the columns will move frictionlessly. Optional rotary tables can be used to enhance the approachability of the measuring probe to complicated work pieces. In the case of advanced CMMs, they have their own computers with interactive dialog facility and friendly software so that the work pieces can be inspected with least effort. And then a map of systematic errors in the machine is built up and fed into the computer system so that the error compensation is built up into the software. Various thermocouples are incorporated throughout the machine and interface with the computer for making the thermal compensation. If there is any variation in the temperature, the thermal compensation is provided by the software. Now what are the different modes of operation? Now, CMMs are available which have manual mode. And in this case, it has a free floating probe. The operator moves the XYZ axis manually to establish contact with the part feature to be measured. The differences in scale readings among the contact points are the measurements. Now you can see this particular picture, the granite table and the work piece and then column bridge etc. Now you can see the operator is holding the probe head and he manipulates the probe. It means manually he moves the probe to make contact with the work piece. For example, this is the probe and then we have a work piece which has a step like this. So the operator moves the probe and he makes contact with this particular surface and records what is the reading. And then he lifts the probe and then it is moved in this direction and again it is moved down. And again the contact is made between the probe and the work piece surface. What is the reading is recorded. Then the difference between these two readings is calculated which will give what is the depth of this step. Like this manually the probe is moved and contact is made with the work piece feature. Readings are recorded and the required value is manually calculated. So this consumes a lot of time and maybe operator may make some mistakes by calculating. And the advancement over manual mode is manual computer assisted mode. In this case, electronic digital displays are provided to CEMM. You can observe here a monitor is provided which indicates the data points. So electronic digital displays are added to CEMM for making zero setting to select the required system or metric system to print data in the standard format. These features that is computer assistance saves time, minimizes calculations and reduces errors. Now we can also see this is a sharp floor CEMM. You can see the CEMM is mounted on this table which has wheels. So wherever measurement is required we can move this coordinate measuring machine with the help of these wheels. And then the measurement can be made. Now let us watch a demonstration of a manual coordinate measuring machine which has a built-in electronic digital display. So in this demonstration I can see the CEMM with X, Y, Z movements. The three movements are manual that means the operator has to hold the axis and he has to move by applying manual force. There is a digital readout interfaced with CEMM. This digital readout shows the coordinates of the selected data points and it also shows the results. The software in the electronic system has many subroutines. We can select appropriate subroutines to calculate various features like circle, angle, straightness etc. Manual zero setting for the three axis also we can observe. There is a touch trigger probe with A and B axis fixed to the z axis probe bar. This demonstration shows the measurement of diameter, angle, straightness, flatness, perpendicularity, depth and slot width. Alright so this is our three axis measuring machine. It's ideal for measuring some machine parts as long as your tolerances aren't too tight or laser, flame jet, water jet cut parts, those sorts of things. It's got a moving gantry so this moves back and forth towards and away from the operator, up and down. The touch probe has a number of articulating positions that you can lock it into. So to do a measurement on a part like this, first thing we're going to want to do is measure the flat surface of the plane to get it aligned. Then we'll measure along an edge to get it straight. Then we'll set a point at the end and we'll make that corner our zero location. So I'm going to bring the probe in, take those, we'll just stay down here. We'll come along the edge, take those and stay there and we'll take that and finish up. Now that we've taken our features, we can go to our display. So we can take that plane that we started with, go to the readout. We'll align that so now it's flat and we'll make that our z axis zero location. We'll go to that edge we measured, we'll align that and we'll make that our y axis zero location. I'll go to that point that we measured and make that our x axis zero. So now we're zero on that corner of the part where this edge, this edge and that plane surface come out and intersect. Now all the features that we measure are going to be taking from that point. So we'll go ahead and probe a circle here and stay there. We can go ahead and probe a circle here and what I'm doing is just pressing the finish key when I've done taking my points and the readout is going to figure out based on the points I've taken what those features are. So now we've got a few features in the readout. We can come up and we can construct a circle through the centers of those two holes and that arc that we just measured. So we'll measure a circle, we'll go into our feature list and check each one of those. So we've got three features, we have finish, now we get the circle that goes through those centers. We've got an x-y position for that and the diameter of that circle. Now on the part, if we want to see if that hole is concentric to this circle pattern, we can come in and check this whole location, finish it up and then up on the readout we can go to a distance. We can select the last hole we measured and the hole we constructed, hit finish and that will give us how far that x-y position varies. To measure an angle on the part, we can come down and we'll probe one edge of the angle, come in and probe the other edge of the angle and up on the readout we'll get a display as to what that angular measurement is. We can also pull up a view and visually see what the angle is and we can change that to the different angle sets depending on which way are parts dimensioned and we get varying angle measurements. When you're done with that, you can just hit the power button, hit the enter key a couple of times. All those features disappear, we can check something else. So with this plasma cut part, we can do something very similar. Let's say we've got an alignment to the center line of this part. We can probe a line here, we can probe a line over here and then up on the readout we can create a line, select those two lines and hit finish and that gives us a midline in between the two Since that's going to be the center of our part, we can go to the readout view, we can align it to that and we can zero out our X axis along that center line and then we can check our feature measurements to that center line. So down the part we can come in and probe each of these hole locations and up in the readout we've got XY centers, we've got a diameter for each of those holes. We can create an arc feature or a circle feature from those and find out what the overall radius is and what the center point of that is as well. So you can check odd shaped laser cut or plasma cut, water jet cut parts using something like this. And next mode of operation is motorized computer assisted CMM. In this case a joystick is used to drive the machine axis. You can see here we have a joystick. So this is a mode in the three axis, X axis, Y axis and Z axis. Accordingly the probe will move. The operator manipulates the joystick to bring the probe into contact with the job. For example, so we have a hole in the surface, then the operator will operate the joystick so that the probe moves in the jet axis, that means it is inserted into the hole. Then it is moved in the X axis, so it makes contact here and the coordinates of this point 1 are recorded and then it is moved to this point by operating the joystick. So the data points of this particular point are recorded. Then again it is moved in this direction and contact is made and then the computer records the coordinates of this point and then the software will calculate. So what is the coordinate of center point and what is the diameter of the hole. So like this using computer the manual calculations are eliminated and the error due to operator is also eliminated. So this is faster when compared to manually operated CMM. Now the another configuration is direct computer controlled CMM. So this is a fully programmable CMM. In this case the machine uses taught locations of colored data to decide where the probe contacts the job and then collects the measurement data. That means the software itself will calculate what is the probe path. Probe path is calculated by the software by using the CAD data that is provided. That means how the probe should move so that path is automatically calculated. The fully automated CMM allows the operator to place the job in a fixture or on a table and run the stored program, collect the data points and generate an output report. I can see here a fully programmable or direct computer controlled CMM. We have the monitor and then we have the computer system, we have the keyboard and then judge things are also available and this is a bridge type coordinate measuring machine with granite table. The complex work piece is directly mounted on the granite table and the probe will move depending upon the program inspection program. The probe will move and it collects the data points and then necessary inspection report is generated by the software. So here operator error is completely errated since the path is calculated by the software and the path is also optimized. Optimized path is calculated by the software so that the inspection time is very much less and there are no chances of collision with the work piece since the path is calculated by using the CAD data the chances of collision of probe with work piece are eliminated. Now let us study what are the different configurations of coordinate measuring machine. The very most common configuration is bridge type coordinate measuring machine wherein we have two columns here. As you can see here there is a column here and there is two columns in this particular case and there is a bridge between these columns. So bridge carries the probe head. This probe head can move up and down so depending upon the work piece height the z axis moment is calculated. Since the probe head is supported by two columns the deflection of the bridge is very less so these bridge type cms are most accurate and this is the dedicated computer system interfaced with the coordinate measuring machine. Now here you can see a huge gigantic coordinate measuring machine. This is the granite table on which very huge large work pieces can be mounted. This is the column 1, column 2 and then we have a bridge which houses the probe head and this is the probe and you can also see the operator to operate the coordinate measuring machine. So very tiny bridge type coordinate measuring machines are also available at the same time gigantic coordinate measuring machines are also available to accommodate large work pieces. The another configuration is cantilever construction which combines easy access and relatively small flow space requirement. It is typically limited to smaller and medium sized machines. I can see here the unlike the bridge type so here one side is completely open so that we can easily load the work pieces on the table from this open end. Parts larger than the measuring table can be inserted into the open side without inhibiting full machine travel. So we have another type of configuration known as gantry type configuration so where the probing head is held by fixed supports. Now you can see this dagger we have fixed supports which will support the bridge. For all these supports we have a guide main so this is one guide main and this is another guide main. So all these guide ways the bridge will move. Probing head is capable of sliding over the supports. The gantry type construction is particularly suited for very large components and allows the operator to remain close to the area of inspection. You can see here motor bike is being inspected by a gantry type coordinate measuring machines. So other type of configuration is horizontal arm coordinate measuring machine. So wherein we have two columns in this particular type of machine we have two columns and then there is a bridge and then there is an overhanging arm which supports the probe head. So in this case we have only one column and then an arm which supports the probing head. So this has an open gen so we can insert large pieces from this open gen. The open structure of this arrangement provides optimum accessibility for large objects such as ties, models and cork bodies. Now in these diagrams we can see moving column type this column can be moved in and out and then we have moving bridge type configuration. So depending upon the type of wood pieces we can select appropriate configuration. Now what are the various parts of coordinate measuring machine? We have main structure of coordinate measuring machine consisting of table, gantry, bridge, column, gantry, horizontal arm and probe head. And then we have machine control unit with driving systems. There is a probing system and then automatic stylus changes also get environmental monitoring system which monitors the temperature using thermocouples. And then there is computer with CMM software to assess the work pieces and then different kinds of accessories can be used during the inspection. So we have a joystick. I can see the joystick. By operating this we can see the three directions X, Y, X, Y and Z. In these directions we can move the probe by operating this joystick. And there is an emergency button also to stop the movement in case of emergency. And then we have probe head and stylus driving system to move the columns, dust covers, granite table on which both pieces are both fixed and can be mounted, thermocouples to assess the temperature variations. So like this different parts are there in the CMM. And then there is a joystick. We can also see an automatic stylus changer which holds the stylus of different configurations depending upon the inspection these probes are automatically selected and fixed into the probe head. And by operating the joystick probe can be moved in next project direction. We can see the joystick here and then the granite table. And then we can also see the four work piece features are more placed on the granite table. And the work piece which is to be inspected is held by these four features. Typical machine working envelope that means the size of the CMM. We have in the X direction movement 500 millimetre to 600 millimetre. In the Y direction the movement is from 400 millimetre to 500 millimetre. And in the Z axis 400 to 440 millimetre with an accuracy of 0.1 micrometer. So this is a tiny CMM. And in the case of country type the X, Y and Z axis movement will be in terms of meters with measurement accuracy of 1 micrometer. Now you can see the automatic stylus changer system which is directly placed on to the work piece table. This holds the probes of different configurations and different lengths. We can also see a non-contact type probe that is optical probe or sometimes it is vision type probe. And here we can see a motorized probe system and probes of different lengths. And we mount it all to the stylus changer. Here you can see a spherical type revolve type stylus. So depending upon the inspection requirement and depending upon the program these probes are selected automatically and inspection is carried out. Then advanced path planning using software. So depending upon the CAD data that is provided automatic probe angle is selected and not path is also selected. You can see here depending upon the work piece say we have a work piece at some angle a hole at some angle. So depending upon the data CAD data provided the probe attains this particular angle. So this angle is automatically selected by the CMM software. Also what is the path of the stylus? So depending upon the CAD data that is provided say probe movement path will be automatically calculated and the collision with the work piece is avoided. And then automatic collision detection also possible using appropriate sensors. And once the path is determined it is optimized depending upon the CAD data. Now we can see here whenever we are using this multiple stylus type probe when the probe moves in this SY and J direction this particular stylus should not touch the work piece. So that CAD is taken by the CMM software. Now let us summarize the lecture number one. In this lecture we discussed about the various aspects of universal measuring machine and we also discussed about the features of coordinate measuring machine. Different modes of operation of coordinate measuring machine and different configurations of CMM and main parts of CMM. With this we will conclude this lecture. We will continue the discussion on the different aspects of CMM in the next lecture. Thank you.