Machinery's Handbook, 31st Edition
816
Surface Texture
Measured Profile Without Electrical Filtering
1 mm
With 0.8 mm Cutoff = 3.5-4.2 m Ra
25 m
With 0.25 mm Cutoff = 1.8-2.2 m Ra
With 0.08mm Cutoff = 0.95-1.05 m Ra
Fig. 6. Effects of Various Cutoff Values Surface Texture Symbol.— The symbol used to designate control of surface irregulari ties is shown in Fig. 7b and Fig. 7d. Where surface texture values other than roughness average are specified, the symbol must be drawn with the horizontal extension as shown in Fig. 7f. Use of Surface Texture Symbols: When required from a functional standpoint, the desired surface characteristics should be specified. Where no surface texture control is specified, the surface produced by normal manufacturing methods is satisfactory provided it is within the limits of size (and form) specified in accordance with ASME Y14.5-2018, Dimensioning and Tolerancing. It is considered good practice to always specify some maximum value, either specifically or by default (for example, in the manner of the note shown in Fig. 8 on page 818). Material Removal Required or Prohibited: The surface texture symbol is modified when necessary to require or prohibit removal of material. When it is necessary to indicate that a surface must be produced by removal of material by machining, specify the symbol shown in Fig. 7b. When required, the amount of material to be removed is specified, as shown in Fig. 7c, in millimeters for metric drawings and in inches for non- metric drawings. Tolerance for material removal may be added to the basic value shown or specified in a general note. When it is necessary to indicate that a surface must be produced without material removal, specify the machining prohibited symbol as shown in Fig. 7d. Proportions of Surface Texture Symbols: The recommended proportions for drawing the surface texture symbol are shown in Fig. 7f. The letter height and line width should be the same as those for dimensions and dimension lines.
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online