Surface Roughness and Form MeasuringJIS B 7513 cag Precision surface plates 4. Se0pe his Japanese Industretal Standard specifies the rectangular or square 4sion surface plates (hereafter referred to as surface plates), of which meeteoe working surfaces ranging £100 160 ma x 100 wa to 2500 2 = 1600 aa. Remarks 1, The applicable standards to this Standard are given in the following: JIS G 5501-Grey tron castings YS % 8103-Glossary of teras used in instrumentation 2. The equivalent International Standards to this Standard are the following: 730 8512-1-1990 Surface plates - Part 1: Cast fron £80 8512-2-1990 Surface plates ~ Part 3: Granite © 2, Definitions For the purposes of this Standard, the following definitions apply, and others are in accordance with JIS Z 8103. (2) preeision surface plates The board shaped structures generally made Of east iron or etone, providing precise flat surfaces or datum flat surfaces for aultipurposes on their upper surfaces as the working surfaces. ? (2) flatness of working surface The magnitude of the deviation from the Sea surface ofthe geouecrically true plane. It is expressed by the dimension of the interval where the interval between the two parallel fist planes becomes the: minisum, when the working surface has been put between two geometrically ,true parallel flat planes. Sy Manes of respective parts The names of respective parts of the surface plate to be used in this ‘Standard shall be in accordance with Fig. 1. ieie==B 7513— Fig. 1. Names of respective parts Made of east tron Made of stone Thlekneas of working surface Side wurfece Ste esta Morking surface Side eerface Side eurface Side surface Reuarks: These Figures are those for simply indicating the naaes of Tespective parts, but are not those for specifying the cosate ruction and shape. 4. Types and grades A Types The types of the surface plates shall be classified into aade of cast Iron and made of stone according to:the materials, and the noainel Sizes of the working surfaces shall be in accordance with Table 1 Table 1. Nominal sizes of working surfaces Unie: mm Shape Nominal size Rectangular tox 100 ‘shape —- 250% 160 ox 20 sox 09 000% eo 1 600% 1 00 | 200100 200% 600 Square shape 20x 250 . “0x a0 60% 60 100 1 06JIS B 7513. (1982) Precision surface plates 4. Scope This Japanese Industrial Standard specifies the rectangular or square cision surface plates (hereafter referred to as surface plates), of which Meee of working surfaces ranging from 160 an x 100 ma to 2500 am x 1600 um Resarks 1. The applicable standards to this Standard are given in the following: JIS G 5501-Grey tron castings JIS Z 8103-Glossary of teras used tn instrumentation 2, The equivalent International Standards to this Standard are the Following: 780 8512-1-1990 Surface plates - Part 1: Cast tron £80 85122-1990 Surface plates ~ Part Granite Definitions For the purposes of this Standard, the following definitions apply, and others are in accordance with JIS z 8103. (2) preeision surface plates The board shaped structures generally made Of cast ifoa or etone, providing precise flat surfaces or datum flat surfaces for multipurposes on their upper surfaces as the working surfaces. 7 , (2) flatness of working surface The magnitude of the deviation from the Sgrklng sivface of The geouetrically true plane. It is expressed by the dimension of the interval where the interval between the two parallel fiat planes becomes the minimum, when the working surface has been put between two geometrically true parallel flat planes. | 4+ Names of respective parts ‘The names of respective parts of the surface plate to be used in this Standard shall be in accordance with Fig. 1. 625 —B7513— 42 Grades The grades of the surface plates shall be the three grades Tap grade 0, grade 1 and grade 2 according to the flatnesses of working porfaces+ 5. Peeformances 5.1 Flatnesses of working surface To the flatnesses of the working surfaces, (00 Kinds of specifications of the flatness in respect to the Shrall surface of the vorking surface and the flatness of local orca in orgpeet to a local area of 250 mm x 250 mm at an arbitrary position of The working surface shall apply. ‘The peripheral rim portion of the working surface corre~ sponding to 2 % of the size of the surface plate width (however, it shall be 20 am in maximum.) may be excluded fron the application of the preseription of Flatness, tf tts portion is in the condition where tt does not cause any tn- convenience in use. Selel Flatness of overall surface The tolerance values for the flat~ | gess of the overall aurface of the working surface shall be in accordance with Table 2. Reaarkst In the case where the size of the working surface is 2500 an x 1600 mn or under and is different in stze from the nominal size, the tolerance values for the flatness shall’ be calculated in accordance with Informative Reference 1. Infornative referenc: Table 2. tolerance values for flatnesses of overall surfaces | meme en | ares [Seema | Stn Tox 6, ery ons 00 eonx169 tox | 38 wl Pa = be 00x 400 45 2 wil 8 1 508 a eae 7] lm Tommi yale Ta—B 7513— Notes (*) These shall be of at 20°C in teaperature and 58 X in hhuatatey. ©) The calculation formula shall be given in Informative Reference 1. Furthermore, values have been rounded off to the nearer values of 0.5 um for grade 0 and 1 ya for grades 1 and 2, 4H 5.1.2 Flatness of local area The tolerance values for flatnesses of local area 750 wa x 250 aa at an arbitrary position shall be in accordant with Table 3. Remarks! As the surface plate of which the Length of the dtagoual Line is snaller than 354 ma has no measuring area of 25) m x 250 um, the prescription of the flatness of local area shall not be applicable. ; eee es cee Table 3. Tolerance values of flatness for local area Units ym Grade| Tolerance values of flatness for local area(*) ~ | 3.5 1 7 2 15 5.2 Rigidity of surface plate The surface plate of 400 mm x 250 ax or over inthe sive of working aittace, when it has been aubjected to a leet ma the center of its working surface, shall be that of having such a rigidity as not exceeding 1 um per 200 N in the flexure at the loaded portion. 6. Shapes and dimensions The tolerance values for respective sizes of the working surfaces of the surface plates shall be 45 % of ite nominal elzea, Furthermore, the heights, thicknesses and masses for the general surface plates shall be as given in Inforaative Reference Table 1. — 628 ——B 751— Informative Reference Table 1. Heights, thicknesses and aasses for surface plates Nostoal cite | Made of cast iro Hade of atone of wording, Siefece oc REE | ete ass te Gieliectise | Eatorbeive Tisfottacive Seieremer™ | reteeeneel stereceed 10x tan z Boe fee 0% 160 om» 50 » * © 100 x0 Construction and appearance The construction and appearance of the surface plates shall be in “accordance with the following: (1) ‘The surface plates shall be provided with three feet. (2) The ribe of the cast tron surface plates shall be so constructed as to lessen the deformations of surface plates a far as possible. () The side curfaces of the cast iron surface plates shall be so constructed as to facilitate handling and traneportation by providing such as grips or holes. (4) the working eurfaces of the grade 0 and grade 1 cast iron surface Plates shall be finished to good quality scraping or to the finish equal to or superior to this, aud of the grade 2 uay be by the same thod or by wachine finish, Furthermore, the distribution of the touching faces of the scraper shall be uniform. —629——B 7513 (5) The working surfaces of the grade 0 stone surface plates shall be finished by good quality lapping, and of the grade 1 and grade 2g, be by the cane method or by the polishing finish. (6) The peripheral rims and each corner of the working surfaces of the surface plates shall be processed with roundings of 2 am or over ig radius of the chanfers of 45° as above. Materials ‘The materials of the surface plates shall be in accordance with the following: (2) The material of the cast iron surface plates shall be FC 250 specified in JIS G 5501 or the cast iron of equal to or superior to this in mechanical properties, and of which structure shall be homogeneous and shall be free from harmful defects such as blowholes, Pinholes and cracks. However, for the grade 2 surface plates, very Small defects of the working surface may be repatred by filler netal of the sane material in composition. Furthermore, for the purposes of removing internal stresses, necessary heat treatment or natural seasoning shall be used, (2) The material of the stone surface plates shall be granite or that ‘equal to or superior to this in physical properties(*), and of which structure shall be homogeneous and shall be free from defects such as cracks and the like. Note (*) The physical properties of the stone material to be used for the surface plates are given in Informative Reference 2s Measuring methods 9.1 Measuring methods of flatness The measuring method of the flatness shall te in Becetdence wlth the following: 9.1.1 Measuring methods for flatness of overall surface The measure- vents for £iataree oF working cuiface of the eurlace plate chall be carried out under the no load condition, eupporting the vorking surface nearly horizontally. The measuring method shall be in accordance with one of the following (D) Method by using @ level (2) Method by using an autocollimeter (3) Method by comparison with a reference surface ‘The neasurenents shall be carried out after the surface plate has tee adapted sufficiently to the ambient temperature and humidity. In addition, in order to avotd the influences of working patterns generated by scraping, cutting and the like, it should be preferable to neasure by placing the block gauge of 30 mmx 9 mm in sectional dimensioas on the measuring poiats on the working surface.-B 7513— ‘The flatness shall be obtained by calculation based on the heights of respective weasuting potnts fron each other measured along the measuring Jfes on the working surface. The sethod to determine the measuring lines shall be tn accordance with either one of the two methods given ia Fig. 2. Fig. 2. Measuring Lines (1) Diagonal Lines method Parallel crosses sethod The neasuring Lines aay be increased by the number of Lines (Example 1 of Pig. 3) accordiag to the cizes of the cutface plates, or by the coabined | petliod of the diagonal Lines mothod and parallel crosses method (Example 2 | of Fig. 3). Fig. 3. Measuring Lines (2) Example 1 Example 2 In order to staplify the calevletion for obtaining flatness, the number of wessuring points on respective measuring ines parallel to the sides of the vorking surface shall be taken ac an odd number, and the intervals thereof ohall generally be in accordance with Table =e—B 7513— Table 4 Intervals between measuring points and nuaber of measuring points Length or width of|Taterval between | Number of working surface jueasuring points | measuring ‘on potas 1 3 2 ae 10 5 1 2 1% a 0 oy Renarks: The interval between measuring points of the working surface Jess than 250 mm in length or width are taken optionally, ‘The interval between the measuring points on a dlagonal line shall be so determined as to coincide at the center, considering the relation given in Table 4 also. An example of the method to obtain flatness from the measured values of| heights of respective measuring points from each other shall be given in the following (the unit in this example shall all be as y The synbole of respective points shall be in accordance with Fig. 4, Fig. 4. Symbols of measuring points (a) The heights of measuring points from each other measured along respective measuring lines AxC 0 0.3 40.8 BXD 0 -7.0 41,0 AEB 0 415.5 47.0 CGD 0 46.4 46.0 BFC 0 -75 © =7.0 DHA 0-900 =7.4 =632—o>) © (a =B 7513~ Obtain the value of the center intersecting point (x), when the heights of both ends of diagonal lines AC and BD have been made the same value. aAxc 0 07 0 BxD 0 -7.5 0 Obtain the values at both ends by adding or subtracting the values of either of the measuring Lines so that the values of above potat (X) become the same value. Whea, the value of BX D Line ts added by (-0.7) - (-7.5) = +608 BXD 46,8 -0.7 +6.8 are obtained. Then the values of the both ends of the measuring lines of periphery other than the diagonal Lines agree with the values of 4 potnts determined in (C), and the values of the middle points thereof are obtained as given in Fig. 5. Fig. 5. Values of measuring points (1) ‘The éifference between the highest point and the lowest point in this case is as follows Highest point #15.4 Lowest point -1.9 _ Difference 17.3 In Fig. 5, when AEB line ts lowered by 4.3 (15.4-1/2 x 6.8) taking the HX F line as an axis, the values of respective points become as given in Fig. 6. Fig. 6. Values of measuring points (2) £ The difference between sp the highest point and the iN : lowest point in this a i case is as follows: Lor ase aa | Highest pofut +11.1 Lowest point 3 Difference 15.4 633 ——B 7513 (£) Purther, ven point A is raised by 1.48 (2/5 the ditference between the point A and che point F), taking the DE line sy axis, the values of respective points become as given in Figs Fig. 7. Values of measuring points (3) The difference tet € ie Ligeia AR lowest potac ta the | | case is as follows: x die: Seale Mighest potar ti | Lovet: poine 2 auth — 450 fe : Difference 13.93 Be The differences between the highest points and the lowest points ia (a), (e) and (£) are (a) > (e)>(£), and the value in (f) 16 the saallest, Therefore, the flatness of this gurface plate shall be 13.9 ua. 9.1.2 uring method of flatness on local area The measuring nethod of the flavaean on the Tocal afea shall be to Tint the portion eheretene {adicator indicates the variation of readings exceeding the tolerance values of the flatness of the local area, scanning completely the surface of the working surface of the surface plate by the datun gauge exemplified ia Fig. 8. As regards this portion, measure the flatness using the method given ta WL-B 7513— Fig. 8. Datum gauge (Example) vate: om ® tase dock @_ Block ® indicator @®, © rads © Plate spring @_ Insulating handle Remarks! Four pieces are in the same plane, and each 260 um? in area. 9.2 Measuring method of cigidity - 9.2.1 Measuring apparatus of rigidity An example of the apparatus shall be given Fag- os Fundonentelly the apparatus shall. be constieuted of the following menbers. (a) A bean integrated with an tndicator (b) A mass support which is independent of the beam in construction (e) A aass for loading 635 —-B 7513— Figs 9. Measuring apparatus of clgtdity (Example) ® bes © supporting tegs (ewo pleces) ® center ass support @® te entra foor (offset) © ass (tor Loading) @ Prectston indteator The bean (B) 1s of rigid construction being supported by two ees (0) and these legs an be positioned at an arbitrary interval along the bess. [At the center of the bean, the third foot (E), being offset fros the center line of the two feet, is provided, and further the indicator (F) being slightly offset towards the center in the same manner is installed so that * gauge head contacts on to the surface plate.=B 7513 shecafore, the foot (B) being offset can accomplish to stabilize the sais TES" Ricy aa tne Gtdeondjeacaene,daview of toe Indiontloe of the Reaceacoes whi Sestae oP oifcee an eiar te Bintnaee ea eaantiieg cere, seilsate apie ertrenelysenail conparedito ithe semmtsot,thevottset)ef the mo Oe The center mass support (B), being independent of the beam, can be goved up and dovn on the eurface plate with respect to the bean withta a Salles "the ceatral area on the cutface plate to which « load 1s applied Hall be 120 na in diameter for the surface plate of leas than 1000 ma x {h00 an in the size of working surface, and be 300 mm in diameter for the Terger aveface plate chan that. ‘The load to be used in the measurement shall generally be not made co such an anount ae to defora the curface plate to 1/2 or over the peraissible Value of the flatness of overall surface. The masses of the maximum Concentrated loads applicable to the surface plates of respective sizes and grades sball be given in Table 5. Table 5. Masses for aaximum concentrated load of surface plates Dimensions of | Masses of the maximum concentrated working loads liable to generate deforma~ surface of tion of 1/2 the tolerance value surface plate | for flatness of overall surface of surface plates with respect to respective grades kg Grade 0 | Grade 1 | Grade 2 400% 250 o « 160 4— 630% 400 0 100 20 1000 630 o 120 240 16001 000, » 60 20 : 2000%1 000 6 180 380 iF 25001 0 us Zo 400 400% 400 6 % a0 630% 630 @ 10 20 1.000% 1 000 we 20 637 —=B 7513~ 9.2.2 Measuring procedures The measuring procedures for rt, etdte surface plates shall be in accordance with the following: tes of (1) The 1eg interval of both ends of beam shall be tnstalied on te Aiagonal Line adjusting to the length of the diagonal Line of hy’ surface plate to be measured. the (2) Set the indicator on the surface plate, and take the reads its value. Pepe (3) Put the specified mass onthe mass support, and take the x of the value of the indicator. rs (4) Resove the mass to ascertain the value of the indicator vader thy ao load condition. (5) Convert the difference of readings of the indicator 4£ (2) and (3) in proportion to per 200 N, and obtain the deformation emouat of the surface plate. 10, Inspection The inspection of the surface plates shall be carried out on the per~ formances, shapes and dimensions, construction and appearance, and saterial, and the results shall satisfy the requirements of 5., 6., 7+ and 8. 11. Designations The surface plate shall be designated by the title of the Standard or ~ number of the Standard, type, grade and size of working surface. Example 1. Precision surface plate, made of cast iron, grade 1, 1000 x 630 Example 2, JIS B 7513, made of stone, grade 0, 1600+x 1000 12. Marking The surface plate shall be marked with the following information. (1) Manufacturer's name or ite abbreviation (2) Serial aunber (3) Grade (4) Nominal size of working surface (5) Mass —633——B 7513 Informative Reference 1. Bases of tolerances on flatness preface This Informative Reference describes tolerances on flatness based on 150 8512, and it does not constitute a part of this Standard. wases of tolerances on flatness of overall surface ‘The tolerances on flatness of the overall surface are based on the following formula: teedter + @ where, ¢ ¢ the tolerance on flatness of overall surface (um) (+ the mom{oal length of the diagonal line of a surface plate being rounded off to the nearest above 100 na (ma) eu G+ constants for the grades of the surface plate, and are given in Informative Reference 1 Table 1. Informative reference 1 Table 1. Values of ¢, and c: ines . @ me 2 1 os 5 2 oe » Surface plates of other than noninal eizes In the case of the surface plates of other than the nominal sizes given fa Table 1 of the text, the tolerance values for flatness of their overall Gurfaces are calculated using the formula (1). 3. Tolerance values.on flatness of Local area The tolerance value on the flatness of local area is the value faleulated from the formula (1), taking the size of working surface as 250 an x 250 aa. zoe=B 7513— Informative Reference 2. Physical properties of stones Preface ‘This Informative Reference describes the physteal properties of stones based on 180 8512-2, and 4t does not constitute a part of this Standard, Physical properties ‘The stones used for surface plates should preferably have the physica properties given in the following (1) Density: 2.5 x 10? to 3 x 10? ke/a? (2) Tensile breaking stress: 7 to 35 N/an? (3) Compressive breaking stress: 100 to 300 N/an? (4) Porosity coefficient: 1.5 % or under (5) Inbibitton coeffictent: 3 % or under (6) Coeffietent of Idnear thermal expansion: 2 to 8 x 10°K*=B 7513— Informative Reference 3. Matters to be attended to 1a handling of surface plates preface This Inforsative Reference describes the matters to be attended to in handiing of the surface plates based oa 180 8512, and it does not constitute Part of this Standard. 4, Matters to be attended in handling Matters to be attended in handitng of the surface plates are in ‘accordance with the following: GQ) A surface plate should preferably be installed in an-atuosphere of controlled tesperature and hunidity. Direct sunlight and abrupt ventilation must be avoided. In addition, it 1s also tportant s0 as not cause a teaperature gradient of upper side and under side such that the working surface and its underside are at differeat teaperatures. Informative Reference: If there is a persistent difference of 1°C between the upper surface and the back surface, in the surface plate of 1000 mn x 630 mm in working surface and 250 wm in thickness, there can be a distortion of about 5 um in a cast iron surface plate and about 1 um ina granite surface plate. These values are equivalent to 80 % and 15 % of the permissible values of flatness of grade 0 respectively. OS a : — (2) The surface plate is to be installed on a firm gtable foundation being sufficiently levelled. (3) In general, after the surface plate has been levelled by the feet of the three horizontal adjusting «crews, adjust the remaining auxiliary feet co as not to impair levelness and giving the minimum deviation from flatness. (4) Referring to the text 9.2, pay attention eo that the surface plate ts not overloaded and disperse the load as much as possible. (5) Since there are local unevennesses on the working surface of the Scraper or machine finished surface plate, the use of point contact ust be avoided. Contact should be made through the block gauge of 10 mm or under in height (see JIS 8 7506) or a similar precision @istance piece. (©) The working surface must be used widely and effectively, and concentrated use always on a certain point aust be avoided. —6n——B 7513 qa (8) ) cao) ay ‘The working surface 1¢ of a datum and must be protected from dan; ‘as much as possible. It must always be kept clean, and a tool ant measuring instrument must not be placed directly on the working surface. ‘The flaws on the working surface of a cast tron surface plate generates burrs. Since these burrs accelerate the weat of the working eurface, the method of elimination is to use 2 grindstone, and then polishing agents shall be completely wiped off. : When the surface plate is left woused, a cover is always to be put the upper face. When it ie not used for a long period, the workt: surface of a cast iron surface plate is coated with a corrosion inhibitor. Since the working surface of a surface plate gets wear by use, the flatness of the working curface is to be inspected periodically according to the frequencies of uses, and it 16 necessary to know the degree of wear. The inspection method of flatness £5 to be in accordance with 9.1 of the text. Spectaltst services of surface plate manufacturers should be uttlizel to repair or recondition surface plate: —642— -