JIS-B-7513-1992-ENG.pdf

JIS B*7513 72 = 4733608 05070b4 024 'JIS UDC 621.753:531.717.8 I JAPANESE INDUSTRIAL STANDARD Precision surface plates Translated and Published by Japanese Standards Association Printed in Japan 11 s JIS B*7533 92 m 4933b08 O507065 TbO m In the event of any doubt arising, the original Standard in Japanese is to be final authority. a I a J I S B*75L3 92 W i.1933608 0507066 9T7 UDC 621.753:531.717.8 JAPANESE INDUSTRIAL STANDARD J I S Precision surface plates B 7513-1992 1 . Scope This Japanese Industrial Standard specifies the rectangular or square precision surface plates (hereafter referred to as surface plates), of which sizes of working surfaces ranging from 160 mm x 100 mm to 2500 mm x 1600 mm. Remarks 1 . The applicable standards to this Standard are given in the following: JIS G 5501-Grey iron castings JIS Z 8103-Glossary of terms-used in instrumentation 2 . The equivalent International Standards to this Standard are the following: IS0 8512-1-1990 Surface plates - Part 1 : Cast iron IS0 8512-2-1990 Surface plates - Part 2 : Granite 2 . Definitions For the purposes of this Standard, the following definitions apply, and others are in accordance with JIS Z 8103. (i) precision surface plates The board shaped structures generally made of cast iron or stone, providing precise flat surfaces or datum flat surfaces for multipurposes on their upper surfaces as the working surf aces. (2) flatness of working surface The magnitude of the deviation from the working surface of the geometrically true plane. the dimension of the interval where the interval between the two parallel flat planes becomes the minimum, when the working surface has been put between two geometrically true parallel flat planes. It is expressed by 3 . 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 . 2 B 7513-1992 Fig. 1 . Names of respective parts Made of cast iron Made of stone . Side Remarks: These Figures are those for simply indicating the names of respective parts, but are not those for specifying the const- ruction and shape. 4. Types and grades 4 . 1 Types The types of the surface plates shall be classified into made of cast iron and made of stone according to the materials, and the nominal sizes of the working surfaces shall be in accordance with Table 1, Table 1 . Nominal sizes of working surfaces Shape Rectangular shape Square shape Unit: mm Nominal size ieox 100 250x 160 400x 250 - 630x 400 1 O O O x 030 1 600x 1 O00 2000x1000 2 600 X 1 600 260x 250 400x 400 630x 630 1 OOOXl O00 -,-,- J I S B*75L3 92 m 4933608 0507068 77T m 160X 100 250X 160 400x 250 3 B 7513-1992 Grade O 3 3.5 4 4.2 Grades The grades of the surface plates shall be the three gradas of grade O, grade 1 and grade 2 according to the flatnesses of working surf aces . a I 6 1 12 7 14 I 8 16 I 10 I 20 12 24 16 33 19 38 23 I 46 7 15 9 17 10 21 14 28 5. Performances 2 188 3 296 5 47 1 8 745 13 1180 20 1880 20 ! 2 236 i 20 2 960 5 354 8 I 566 i 13 89 1 ! I 1414 I 20 5.1 Flatnesses of working surface To the flatnesses of the working surfaces, two kinds of specifications of the flatness in respect to the overall surface of the working surface and the flatness of local area in respect to a local area of 250 mm x 250 mm at an arbitrary position of the working surface shall apply. Remarks: 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 mm in maximum.) may be excluded from the application of the prescription of flatness, if its portion is in thecondition where it does not cause any in- convenience in use. 5.1.1 Flatness of overall surface The tolerance values for the flat- ness of the overall surface of the working surface shall be in accordance with Table 2 . I Informative reference: In the case where the size of the working surface is 2500 mm x 1600 mm or under and is different in size from the nominal size, the tolerance values for the flatness shall be calculated in accordance with Informative Reference 1 . Table 2. tolerance values for flatnesses of overall surfaces flatness of overall for Excluding width Length of surface()(Z) um ! of peripheral I diagonal line m I Grade 1:Crade 21 j portion mm (Informative I reference) I Nominal size of working + surtace ma I 630x 400 1 O O O x 630 1600x1000 2 O00 x 1 O00 8 9.5 2 500 x 1 600 250x 250 400x 400 630x 630 1 O00 x 1 O00 11.5 3.5 4.5 5 7 J I S B*7513 92 m 4933608 05070b9 bob m 4 B 7513-1992 Notes (l) These shall be of at 20°C i n temperature and 58 X i n humidity . The calculation formula shall be given i n Informative Reference 1 . (*) Furthermore, values have been rounded off t o the nearer values of 0.5 um for grade O and 1 um for grades 1 and 2. 5.1.2 Flatness of local area The tolerance values for flatnesses of local area 250 mm x 250 mm at an arbitrary position shall be i n accordance with Table 3. Remarks: As the surface plate of which the length of the diagonal line is smaller than 354 mm has no measuring area of 250 mm x 250 mm, the prescription of the flatness of local area shall not be applicable. Table 3. Tolerance values of flatness for local area Unit: u m Grade Tolerance values of flatness for local area(' 21 15 5.2 Rigidity of surface plate The surface plate of 400 mm x 250 mm or over i n the size of working surface, when it has been subjected to a load on the center of its working surface, shall be that of having such a rigidity as not exceeding 1pm per 200 N i n 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 - 15 % of its nominal sizes. Furthermore, the heights, thicknesses and masses for the general surface plates shall be as given i n Informative Reference Table 1 . -,-,- JIS B*75L3 92 W 4933608 0507070 328 m of working surface mm 5 B 7513-1992 Height Mass kg (informative (Informative Informative Reference Table 1 . Heights, thicknesses and masses for surface plates Nominal size I Made of cast iron Made of stone Mass kg (Informative reference) Minimum thickness um (Informative reference) - I reference) I reference) e r 160X 100 , i t - - 50 15 400x 250 630X 400 70 50 100 180 1OOOx 630 1600x1000 250 900 160 720 2 ooox 1 O00 1350 2 500 X 1 600 200 250 1 120 2 800 50 10 250X 250 400X 400 70 30 70 80 630X 630 1 O00 x 1 O00 100 280 7 . Construction and appearance The construction and appearance of the surface plates shall be in accordance with the following: e (1) The surface plates shall be provided with three feet. (2) The ribs of the cast iron surface plates shall be so constructed as to lessen the deformations of surface plates as far as possible. (3) The side surfaces of the cast iron surface plates shall be so constructed as to facilitate handling and transportation by providing such as grips or holes. ( 4 ) The working surfaces of the grade O and grade 1 cast iron surface plates shall be finished to good quality scraping or to the finish equal to or superior to this, and of the grade 2 may be by the same method or by machine finish. Furthermore, the distribution of the touching faces of the scraper shall be uniform. -,-,- J I S B*7513 92 H 4933bOB 0507071 2b4 6 B 7513-1992 (5) The working surfaces of the grade O stone surface plates shall be finished by good quality lapping, and of the grade 1 and grade 2 may be by the same 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 mm or over in radius or the chamfers of 45' as above. 8. Materials The materials of the surface plates shall be in accordance with the following: (1) The material of the cast iron surface plates shall be FC 250 specified in JIC 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 repaired by filler metal of the same 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( 3 ) , and of which structure shall be homogeneous and shall be free from defects such as cracks and the like. Note ( 3 ) The physical properties of the stone material to be used for the surface plates are given in Informative Reference 2. 9. Measuring methods 9.1 Measuring methods of flatness The measuring method of the flatness shall be in accordance with the following: 9.1.1 Measuring methods for flatness of overall surface The measure- ments for flatness of working surface of the surface plate shall be carried out under the no load condition, supporting the working surface nearly horizontally. following: The measuring method shall be in accordance with one of the (1) Method by using a level (2) Method by using an autocollimeter (3) Method by comparison with a reference surface The measurements shall be carried out after the surface plate has been adapted sufficiently to the ambient temperature and humidity. In addition, in order to avoid the influences of working patterns generated by scraping, cutting and the like, it should be preferable to measure by placing the block gauge of 30 mm x 9 mm in sectional dimensions on the measuring points on the working surface. -,-,- JIS B*75L3 92 4933608 0507072 LTO B 1 7 B 7513-1992 The flatness shall be obtained by calculation based on the heights of respective measuring points from each other measured along the measuring lines on the working surface. The method to determine the measuring lines shall be in accordance with either one of the two methods given in Fig. 2 . Fig. 2 . Measuring lines (1) Diagonal lines method Parallel crosses method The measuring lines may be increased by the number of lines (Example 1 of Fig. 3) according to the sizes of the surface plates, or by the combined method of the diagonal lines method and parallel crosses method (Example 2 of Fig. 3). Fig. 3 . Measuring lines (2) Example 1 Example 2 In order to simplify the calculation for obtaining flatness, the number of measuring points on respective measuring lines parallel to the sides of the working surface shall be taken as an odd number, and the intervals thereof shall generally be in accordance with Table 4 . -,-,- J I S B87513 72 W 4733608 0507073 037 W 8 B 7513-1992 Table 4 . Intervals between measuring points and number of measuring points points 630 140 1 O00 I 155 I 7 Remarks: The interval between measuring points of the working surface less than 250 mm in length or width are taken optionally. The interval between the measuring points on a diagonal line shall be so determined as to coincide at the center, consldering the relation given in Table 4 also. An example of the method to obtain £latness from the measured values of heights of respective measuring points £rom each other shall be given in the following (the unit in this example shall all be as p m ) . The symbols of respective points shall be in accordance with Fig. 4. Fig. 4 . Symbols of measuring points F Li (a) The heights of measuring points £rom each other measured along respective measuring lines A X C O -0.3 4 - 0 . 8 B X D O -7.0 4 - 1 . 0 A E B O +15.5 +7 . O C G D O +6.4 1 . 6 . 0 B F C O -7.5 -7.0 D H A O -9.0 -7.4 -,-,- e e e e JIS BW75L3 92 4933608 0507074 T73 m 9 B 7513-1992 (b) Obtain the value of the center intersecting point (XI, when the heights of both ends of diagonal lines AC and BD have been made the same value. A X C O -0.7 O B X D O -7.5 O (c) Obtain the values at both ends by adding or subtracting the values of either of the measuring lines so that the values of above point (X) become the same value. When, the value of B X D line is added by ( - 0 . 7 ) - (-7.5) + 6.8 B X D +6.8 -0.7 +6.8 are obtained. (d) Then the values of the both ends of the measuring lines of periphery other than the diagonal lines agree with the values of 4 points 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 difference between the highest point and the lowest point in this case is as follows: Highest point +15.4 Lowest point -1.9 Difference 1 7 . 3 (e) In Fig. 5, when A E B line is lowered by 4.3 (15.4-1/2 x 6.8) taking the H X 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 the highest point and the lowest point in this case is as follows: Highest point +11.1 Lowest- point -4.3 Difference 15.4 -,-,- _ JIS B*75i13 92 4933608 0507075 90T W 1 0 B 7513-1992 (f) Further, when point A is raised by 1 . 4 8 (2/5 the difference a between the point A and the point F), taking the D E line as an axis, the values of respective points become as given in Fig. 7 . Fig. 7. Values of measuring points (3) The difference between the highest point and the lowest point in this case is as follows: Highest point +11.1 Lowest point -2.82 13 . 92 Difference a 4 13.9 The differences between the highest points and the lowest points in ( d ) , (e) and (f) are (d) (e) (f); and the value in (f) is the smallest. Therefore, the flatness of this surface plate shall be 1 3 . 9 ym. 9 . 1 . 2 Measuring method of flatness on local area The measuring method of the flatness on the local area shall be to find the portion where the indicator 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 datum gauge exemplified in Fig. 8 . As regards this portion, measure the flatness using the method given in 9.1.1, J I S B*75L3 72 m 4733608 0507076 846 m 11 B 7513-1992 Fig. 8 . Datum gauge (Example) Unit: mm Base block Block Indicator , 0 Pads Plate spring Insulating handle Remarks: Four pieces are in the same plane, and each 280 mm2 in area. 9 . 2 Measuring method of rigidity 9 . 2 . 1 Measuring apparatus of rigidity An example of the apparatus shall be given in Fig. 9 . of the following members. Fundamentally the apparatus shall be constituted (a) A beam integrated with an indicator (b) A mass support which is independent of the beam in construction (c) A mass for loading -,-,- JIS !3*75L3 92 m 4933608 0507077 78