For example, vibrations affect steel strips during rolling and transportation, producing random or periodic vertical movements of the strips as they move forward along a roll path. Handbook of dimensional measurement, fifth edition features one completely new chapter covering the measurement of geometric dimensions and tolerances, while providing comprehensive stateoftheart treatment of all known dimensional measurement devices and techniques. For use with kemet flat lapping and polishing systems, kemet flatness measuring equipment is designed to assist in the measurement and maintenance of surface flatness. Flatness inspection is a fundamental issue in the quality control performed during the manufacturing of steel strips. In this example an axis is constructed through the base of the component and saved as a datum. The light ribbon is imaged by a ccdmatrix camera, as shown in figure 12. Flatness is can be measured using a height gauge run across the surface of the part if only the reference feature is held parallel. With the hs2000, flatness can be measured on the full 400x500mm area with less than 1micron of deviation in a very short time. This gives extremely precise measurements, more accurate than most cmm measurements, in an economical way. Four other extremevalue height descriptors in limited use, are.
The measurement data obtained from these inspection devices have to be further processed and analyzed, to assess the geometric form of the manufactured components. Recently, an optical technique based on diffused light was being used in the steelmaking industry for flatness measurement. May 20, 20 instructional video that clearly demonstrates how fixturlaser instrument performs flatness measurement. Decide the number of measurement points and which three will be the reference points on which the laser plane will rest. Catr with different serrated reflectors krishna tottempudi, venkata rama on. Asme b89 is collection of metrology standards that tell you how to measure b89. Flatness is applied to an individual surface, flatness tolerance does not need to be related to a datum. Below is my understanding of flatness, please correct me if i am wrong. Evaluation of straightness and flatness error using. Reference plane reference surface gradient measurement zernike. In this section, some flatness assessment methods are summarized. Search the worlds most comprehensive index of fulltext books. Netherlands measurements institute, van swinden laboratory. The simplest technique for flatness measurement involves a.
Because no stitching is needed for large surfaces, the chromatic confocal technique can accurately measure in seconds these in addition to detecting local defects. Whether youre new to engineering or an industry veteran, the specialized knowledge you gain from our course will strengthen your professional skill set and help you advance in your career. Evaluation of cmm for flatness measurements request pdf. This would be measuring parallelism instead as you are fixing the bottom of the part as a datum. On the calibration of surface plates sciencedirect. Straightness and flatness of produced parts are basic requirements in engineering design and manufacturing, and have been examined extensively in the literature of precision manufacturing engineering. This article includes recommendations for flatness and levelness based on program type. The most common method within the flat lapping sector is by using a monochromatic sodium light unit and an optical flat. To perform flatness measurements using the moody method, carry out the following steps. They have resolution of less than one millionth of an inch and they are very fast and operator friendly. The actual flatness of the measurement line will be the algebraic sum of the reading d1, d2 etc plus the reading at the datum. How does cmm software calculate flatnessperpendicularity. The flatness problem also known as the oldness problem is a cosmological finetuning problem within the big bang model of the universe. The best available way to check machine travel and flatness of things like surface plates is with a laser interferometer such as sold by hewlett packard.
The method of determining the flatness deviation of a surface plate, using differential. Laser flatness measurement automotive laser flatness measurement automotive laser displacement sensors need speed, accuracy and the capability to provide excellent performance in any application. The flatness control c defines how much a surface on a real part may vary from the ideal flat plane. The handbook of dimensional measurement is a unique resource organized into chapters by gage gauge type and function. A new generation optical flatness measurement systems. Flatness metrology measurement optical flats optical flats are used to test the flatness of finelapped surfaces such as the measuring faces on gauge blocks, measuring inserts, measuring tables, micrometers etc. Completing our course is like adding five years of experience to your resume. There are a number of ways to measure the flatness of a surface. Interference fringes appear when the optical flat is laid on the surface to be tested. The consequences of these vibrations are particularly harmful for 3d reconstruction and flatness measurement based on noncontact techniques. An optical flatness measurement system for mediumsized surface. Measurement of surface form by laser profilometry springerlink. To understand the basic principles and techniques of flatness measurement refer to. Individual chapters move from simple to complex, from timeless measurement techniques to the most modern and innovative.
Extraction strategies for flatness deviation evaluation. Lapmaster optical flats are manufactured using the finest quality materials and the latest manufacturing techniques. Aug 09, 20 recently, an optical technique based on diffused light was being used in the steelmaking industry for flatness measurement. Definitions according to iso 1101 and generalities.
For a plane flatness, it calculates the distance between 2 planes which are parallels, and seach the orientation that allows to have the distance mini between them and contains all the measured hits. Surface texture includes 1 roughness nano and microrough. This technique requires a very uniform, diffused light ribbon projected onto the surface of the product to be measured. The flatness evaluation method which has been described. Changing demands on flatness data traditionally, flatness measurement has been done manually using a straight reference straight edge or thin wire under tension and a wedge or feeler gauge. S quabis 1, m schulz 1, g ehret 1, m asar 2, p balling 3, p kren 3, r h bergmans 4, a kung 5, a lassila 6, d putland 7, d williams 7, h piree 8, e prieto 9, m perez 9, l svedova 10, z ramotowski 11, m vannoni 12, f hungwe and y kang 14. Two sets of parallel planes where the entire referenced surface must lie. In these situations, more limited extraction strategies are used is that providing a more specific information in the flatness evaluation. Flatness fundamentals why measure flatness the evaluation of flatness deviation is essential to control flat surfaces of workpieces and often to qualify a surface as a primary reference to which the other workpiece elements are referred with orientation and position tolerances. Shape is a key characteristic to determine the quality of outgoing flatrolled products in the steel industry.
The absolute flatness of the surfaces may be measured through the use of the threeintersection method by nearinfrared interferometry. They are also very expensive, although the price has come down a lot in the last ten years. As for flatness measurement, the traditional method of flatness measurement is either to measure directly by using largescale highprecision equipment or to determine the flatness after defining the ideal plane by measuring the height difference between the actual plane and ideal plane after determining the reference plane. Flatness tolerance is always less than the dimensional tolerance associated with it.
Easier to read than asme b89 measurement documents. Based on the current measuring methods and the actual engineering project, a new noncontact highprecision, lowcost large 2d flat workpiece flatness measuring system is developed, in which. The double laser line approach permits local surface slope measurement in addition to 3dposition which can be used for material vibration compensation as well as elastic deformation compensation to some. The laser beam is adjusted according to the vials on the laser transmitter, and the measurement value at the first measurement point is set to zero. Methods exist by which deviations from a perfect form can be determined. Another measure of surface roughness is an extremevalue height descriptor anonymous, 1975, 1985 r t or r y, r max, or maximum peaktovalley height or simply pv distance. Flatness measurement component axis squareness on a cone although it is possible to measure the flatness of a cone along a single trace, squareness is not possible. In the present work, algorithms based on computational geometric techniques have been developed for minimum zone and functionoriented evaluation of straightness and flatness. Flatness cannot be measured by simply placing the part on a granite slab and running a height gauge or microheight over it. A flatness measurement is now made around the conical area of the part. By aiming for the worlds best in every aspect, the lkg5000 is built with the latest cuttingedge technology.
It covers rf test and rf measurements parameters viz. Rf measurements tutorial rf device test and measurement. Online flatness measurement in the steelmaking industry. G 1 with the flatness interferometer the deviations from the flatness of surfaces f. Dec 23, 20 for a plane flatness, it calculates the distance between 2 planes which are parallels, and seach the orientation that allows to have the distance mini between them and contains all the measured hits. We use a laser line triangulation method for online measurement of manifested flatness based on a laser projector with two parallel lines. Realtime system for flatness inspection of steel strips. The flatness measurement of a large 2d flat workpiece such as a satellite solar panel substrate is a key problem in its manufacturing process. Ff and fl numbers are used to measure the flatness and levelness of concrete floors. The flatness tolerance zone is the volume between two parallel planes. Instructional video that clearly demonstrates how fixturlaser instrument performs flatness measurement. An optical flatness measurement system for mediumsized surface plates.
This rf measurements tutorial covers rf device testing basics using rf equipments. The quality requirements for such products have been increasing for the last years, and nowadays new flatness measurement techniques are needed to fullfill this requirements. Practical machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. This study represents an initial step toward the measurement of flattened silicon surfaces using a nearinfrared interferometer. This study represents an initial step toward the measurement of flattened silicon surfaces using a. It has up to now been almost accepted that precision measurement of the shape of a. Angle interferometer flatness measurement the height profile the profile of deviations from flatness is the result of a number of individual straightness measurements made along a grid of lines fig. Flatness can be defined as a condition of having a smooth, even, and level surface without a slope, tilt, or curvature.
Provided by productivity quality incs metrology toolbox 763. Using the measurement data, the analysis software provided with the cr750 can produce flatness parameter values that can be used to verify that a given wafer is in compliance with peaktovalley height range the manufacturer has specified. It is greatly influenced by flatness, a feature to describe how the surface of a rolled product approaches a plane. Well explain how dichroic beamsplitter flatness affects an optical wavefront in reflection, and how to calculate the practical impact of flatness specifications on your system. Such problems arise from the observation that some of the initial conditions of the universe appear to be finetuned to very special values, and that small deviations from these values would have extreme effects on the appearance of the universe at the. Flatness cannot be measured by simply placing the part on a granite slab and. Floor flatness and joints understanding fnumber requirements and jointing for commercial and industrial floors. This is still performed by some steel and metal producers, but automated measurement using optical gauges become more and more common. The simplest technique for flatness measurement involves a depth gage connected to a dial indicator.
Intercomparison of flatness measurements of an optical flat at apertures of up to 150 mm in diameter. A new noncontact flatness measuring system of large 2d. Part of the nato asi series book series nsse, volume 1. Architects should understand what the numbers mean and how to specify concrete floor flatness and levelness. Evaluation of cmm for flatness measurements article in metrology and measurement systems 154.
Perfect flatness is when all points of a surface lie in the same plane. This presentation details the traditional measurement techniques. Many technical methods have been proposed for the measurement of surface flatness according to the size and the quality of the surface to be inspected. Sensors free fulltext online flatness measurement in the. The field of superresolution microscopy srm has exploded in recent years, giving rise to techniques. Flatness tolerance provides a tolerance zone of specified and defined by two parallel planes in where the specified surface must lie. Cirp encyclopedia of production engineering, chapter. Optical flats are used to test the flatness of finelapped surfaces such as the measuring faces on gauge blocks, measuring inserts, measuring tables, micrometers etc. Flatness measurement tactile pressure indicating sensor.
The flatness interferometer consists of the following components, fig. Fnumbers were developed in the 1980s to provide a systematic, quantitative way to indicate the flatness and levelness. Smc plates, and glass plates, which are difficult to measure by traditional methods. How to measure flatness with optical flats by van keuren. Flatness measurement with a reference plane parallel to the horizontal plane.
The optical flats are made either from the highest quality clear fused quartz, which is known for its very low thermal expansion characteristics and resistance to abrasion, or zerodur, a glass ceramic. Pdf on oct 14, 2014, han haitjema and others published flatness find, read and. Intercomparison of flatness measurements of an optical. The procedure is based on the progressive angle measuring. Flatness is a condition of a specified surface having all elements in one plane. This chapter covers the details on the analysis and measurement of surface roughness. Flatness is can be measured using a height gauge run across the surface of the part if. Absolute flatness measurements of silicon mirrors by a. The measurement of flatnesstwist on circular planes such as flanges is also based on the use of three reference points, situated at intervals of 120 around the circle.
1482 1331 1556 1153 1300 97 713 870 205 1122 1517 1432 786 1562 86 432 94 943 1574 374 1519 1249 733 994 791 1488 542 326 702 425 261 1430 1425 164 18 1026 1329 674 311 1492 916