Machinery's Handbook, 31st Edition
824 ISO Textural Descriptions ISO 1302:2002 does not define the degrees of surface roughness and waviness or type of lay for specific purposes, nor does it specify the means by which any degree of such irreg ularities may be obtained or produced. Also, errors of form such as out-of-roundness and out-of-flatness are not addressed in the ISO surface finish standards. This edition does bet ter illustrate how surface texture indications can be used on castings to reflect machining allowances (Fig. 2) and how symbology can be attached to geometric dimensioning and tolerancing symbology (See Fig. 3).
U Rz 0.9 L Ra 0.3
MRR U Rz 0.9; L Ra 0.3 Fig. 4. Indication of Bilateral Surface Specification Shown Textually and as Indicated on a Drawing
turned Rz 3.1
MRR turned Rz 3.1
Indication of a machining process and requirement for roughness shown textually and as indicated on a drawing. Fig. 5a. Indication of Manufacturing Processes or Related Information Fe/Ni15p Cr r Rz 0.6 NMR Fe/Ni15p Cr r; Rz 0.6
Indication of coating and roughness requirement shown textually and as indicated on a drawing.
Fig. 5b. Indication of Manufacturing Processes or Related Information
Upper (U) and lower (L) limits Filter type "X." Gaussian is the current standard (ISO 11562). Previously it was the 2RC-filter, and in the future it could change again. It is suggested that companies specify Gaussian or " 2RC" to avoid misinterpretation.
Evaluation length ( ln )
U "X" 0.08-0.8 / Rz8max 3.3
Transmission band as either short-wave and/or long-wave Surface texture parameter. First letter is Profile (R, W, P). Second character is Characteristic/parameter: p, v, z, c, t, a, q, sk, ku, m, ∆ q, mr ( c ), δ c, mr. See ISO 4287
Limit value (in micrometers)
Interpretation of spec limit: 16% or max
Manufacturing process
ground U "X" 0.08-0.8 / Rz8max 3.3
Material removal allowed or not allowed (APA, MRR, NMR) Surface texture lay Fig. 6. Control Elements for Indication of Surface Texture Requirements on Drawings
Copyright 2020, Industrial Press, Inc.
ebooks.industrialpress.com
Made with FlippingBook - Share PDF online