1、STD.AA SUP-1-ENGL 1775 = Ob04500 002878L 474 I- -v I Understanding Aluminum Extrusion Tolerances The Aluminum Association I- I lid n II: 1 1 n L I, I mil rn STDOAA SUP-II-ENGL 1995 Ob04500 OOII782320 About The Aluminum Association The Aluminum Association represents primary and secondary producers o
2、f aluminum, as well as semi- fabricated products, Member companies operate approximately 400 plants in 30 states. The Associations mission is to increase understanding of aluminum and the aluminum industry and increase aluminums use through its technical, statistical, marketing and informational act
3、ivities and services. The Associations programs are designed to serve its customers, consumers, educators, students, government and the public generally. For the aluminum industry and its customers, the Association develops standards and designation systems, prepares codes and specifications involvi
4、ng aluminum products and addresses technical and marketing issues for the industry. The Association is the leading source of statistics for the aluminum industry. Copyright 1990. Unauthorized reproduction by photocopy or any other method is illegal. The Aluminum Association, Inc. 900 19th Street, N.
5、W. Washington, D.C. 20006 First Edition January 1990 Second Edition February 1995 STD-AA SUP-1-ENGL 1995 O604500 00118783 267 Understanding Aluminum Extrusion Tolerances his publication explains and illustrates many aspects of the published standard tolerances for aluminum T alloy extrusions, such a
6、s those contained in The Aluminum Associations Aluminum Standards and Data and the American National Standard Dimensional Tolerances for Aluminum Mill Products, ANSI H35.2. These standards are maintained by The Aluminum Association, the latter on commission by the American National Standards Institu
7、te (ANSI). The tolerances published in Aluminum Standards and Data and in ANSI H35.2 result from the voluntary consensus standards development process prescribed by ANSI. Hence, the existence of the standards do not preclude an individual or organization fiom manufacturing, marketing, purchasing, or
8、 using products not conforming to the tolerances covered by the standards and discussed in this publication. The publication and the videotape upon which is was based were developed under the guidance of a technical task force of The Aluminum Associations Extruded Products Division, which sponsored
9、their production. While the task force used its best efforts to ensure the accuracy of the content, the task force, the Extruded Products Division, and The Aluminum Association do not warrant, guarantee, or otherwise assume any responsibility for the use of the information provided in any specic app
10、lication. This publication, Understanding Aluminum Extrusion Tolerances, was originally written as a supple- ment for a 30-min video with the same title. The section and page numbers used in the publication were intended as references to sections of that videotape; in using the publication by itself
11、, those designations have no special significance. The videotape Understanding Aluminum Extrusion Tolerances is stili avail- able for purchase from The Aluminurn Association at the address printed inside the front cover. Acknowledgement is made to Aluminum Association consultants Stan Benjamin and P
12、aul V. Mara for valuable technical assistance with the project leading to this publication and the associated videotape. - STD-AA SUP-1-ENGL 1995 Ob04500 0018784 lT3 m APPENDIX Gap Width Inches 0.040-0.062 0.063-0.124 0.1 25-4.249 0.250-0.499 O .500-0.999 1 .000-1.99 2.000 and over iml Extrusion For
13、ms c.1-1 CLASS 1 CLASS 2 Group A Group B Group A Group B Alloysa Alloys Alloys 0 Alloys Ratio ) 2.0 1.5 2.0 1 .o 3.0 2.0 2.5 i .5 3.5 2.5 3.0 2.0 4.0 3.0 3.5 2.5 4.0 3.5 3.5 2.5 3.5 3.0 3.0 2.0 3.0 2.5 3.0 2.0 Hollow Shapes C.4 Solid Shapes C.5, C.6 Semihollow Shapes C.6, C.7, C.8 Definitions of Pro
14、ducts n dctermining the general configurations of desired shapes, notc the several basic classifications: solids, semiholiow, hollow, etc. These shapes are ail pro- ducible, but for economic consideration, solid shapes are most economical with costs increasing for the hoiow shapes for both metal and
15、 tooling. The produc- ers engineering and design personnel can be of assis- tance in re-designing, if needed, shapes which will ful- fill the desired function, yet reduce overall costs. How- ever, even the most intricate extruded shapes may Of- ten still be the most economic solution to your specifi
16、c need. l ExffuSbn: An extrusion is a product formed by pushing metal through a die. xtnrded ShUp: An extruded shape is a wrought product that is long in relation to its cross sectional dimensions and has a cross section other than that of sheet, plate, rod, bar, tube or wire. solid Extnrded ShUpe:
17、Any exuuded shape other than a hollow or semiholiow shape. Example, Figure 1. Figure 1 EXtnrded Rod: A solid extrusion whose cross section is round, and whose diameter is 0.375-inch or greater. Smaiier sizes are classified as wire. Table 1 : Classification-Semihollow Extruded Shapes STD-AA SUP-1-ENG
18、L 1995 W Ob04500 0038785 03T m Semihollow Shapes C.6 Figure 2 Typical Semihollow Extruded Shapes. Use Void Area D and Gap Width B or Void Areas C and D and Gap Width A, Whichever Results In Larger Ratio. Cbss I Semihollow Extruded Shape: A semihollow extruded shape of two voids or less which in the
19、area of the voids and surrounding metal thickncss is symmetrical abut the centeriine of the gap. Example, Figures 3 and 4. Figure 3: Typical Class 1, Semihollow Extruded Shape Class 2 Semihollow Extnrded Shcrpe: Any semihoilow exmded shape other than Qass 1. Example, Figures 5 and 6. n Figure 5: Typ
20、ical Class 2, Semihollow Nonsymmetrical Void, Symmetrical Surrounding Metal Thickness Figure 4: Typical Class 1, Semihollow Extruded Shape Figure 6: Typical Class 2 Semihollow Symmetrical Void, Non-symmetrical Surrounding Metal Thickness STD-AA SUP-1-ENGL 1795 Ob04500 0016786 T7b Hollow Shapes C.4 H
21、ollow fxtruded Shape; An extruded shape, any part of whose cross section completely encloses a void. CksJ I Hollow ExtBldedShape: A hollow exuuded shape whose void is round and one inch or more in diameter and whose weight is equaiiy distnbuted on opposite sides of two or more equaiiy spaced axes. E
22、xample, Figure 7. Ckcrss 2 lfo/bw Extnrdedshape: Any holiow extruded shape other than class 1 which does not exceed a 5-inch circumscribing circle and has a singie void of not less than 0.375-inch diameter or 0.1 10 square inch area. Example, Figure 8. Figure 7: Class 1 Hollow Extruded Shape II Figu
23、re 8 Class 2 Hollow Extruded Shape ChSS 3 ffObw hdet than class 1 or class 2. Example, Figure 6. Ope: An hollow extruded shape other Tube: A hollow section that is long in relation to its cross-section, which is symmetrical and is round, square, rectangular, hexagonal, octagonal, or ellipticai, with
24、 sharp or rounded comers, and having uniform wall thickness except as affected by comer radii. DrUWfI Tube: A tube having final dimensions produced by drawing through a die. Extruded Tube: A tube produced by hot extrusion. Pipe: A tube having certain standardized combinations of outside diameter and
25、 wall thickness, commonly designated by Nominal Pipe Sizes and ANSI (American National Standarh Institute) Schedule . Numbers. Figure 9 Class 3 Hollow Extruded Shape (“his information adapted from: Drafiing Standards for Aluminum Extruded and Tubular Products, The Aluminum Association, Washington, D
26、C, 1981) STD-AA SUP-1-ENGL 1995 W 0604500 0018787 902 W - APPENDIX JD.2/ Individual Tolerances D.2-1 Importance of Determining Tolerances Individually n examining extruded product specifications, it may sometimes ap I pear that if certain specifications are within standard tolerances, they should gu
27、arantee the accuracy of others as well. It is never safe to make that assumption. It is very important to determine and inspect each appiicabe standard tolerance individually, independent of all others. Consider, for example, a simple extruded channel of alloy 6063 with these dimensions and the stan
28、dard tolerances indicated by Tables 1 1.2 (Cross-Sectionai Dimension Tolerances) and 1 1.12 (Angularity) in ASD, 1988. See Figure 1. Even in this simple shape, several dimensions can be comfortably within tolerance, while another is not. Example 1, Tipre 2. In this example, the bottom and sides of t
29、he channel are ail 0.012 less than their specified dimension of 1 .ooo“, while the top-outside measures 0.023“ more than its specified dimension of 1 .ooo“ and angle at the left measures exactly 90 degrees. Ail of those dimensions are within their standard tolerances. But the angle at the right, the
30、n, must be 92 degrees, 2 minutes - 2 degrees, 2 min- utes larger than specified and 2 minutes larger than its allowable tolerance. in Example II, Figure 3, the sides and bottom each measure 1 .ooo“, ex- actly as specified. Each angle is 91 degrees, one degree larger than speci- fied, but well within
31、 the +/-2.Megree tolerance allowed by ASD Table 11.12. inch larger than the aiiowed tolerance of 1.ooo“ +/- 0.023. But the topoutside dimension is 1.035 inches, which is 0.012- Figure 1 91 Wo #. t-l.wO+ Figure 3 STD-AA SUP-L-ENGL 1995 Ob04500 0018768 849 - APPENDIX D.2 Individual Tolerances D.2-2 As
32、 the figures in Example III, Fgure 4 make clear, ;niganty in this shape can be far out of tolerance even if aU of the perimeter linear dimen- sions are exactly as specified. in fathe angies can take on any vahe at all, while he perimeter mains within tolerance! Faure 4 Many other examples muid be pv
33、ided, but he point mains the same: each tolerance must be determined anci inspected independently of other tol- erances. STD-AA SUP-II-.ENGL II995 W Ob04500 OOL8789 785 W APPENDIX Flatness Tolerancing G.1-1 What A Flatness Tolerance Means fa surface width of an extrusion is intended to ap- amount ai
34、iowed for its width -the tolerance values. The baseline for fiames tolerancing is the ideal straight line connecting the two end points of the profiled surface (in effect, an ideal flat plane, seen end-on). See Figure 1. pear in cross section, as a suaight line, a standar I tolerance for flatness ap
35、plies to that width. That means that this surface, measured in cross- section at any location dong the exmion, may not deviate from a perfectly straight line by more than the +rT+ 4r-z-7- Fgure 1 The profiled piane must lie entirely within two planes which: side of the baseline (see Figui.c 2); 1. J
36、ust touch, but do not penetrate, (are tangent to) the surface on either ,=m= Right =m= I Wrong Figure 2 2. Are parallel to Lhe baseline (see Figure 3); Right Wrong Figure 3 3. And are separated by a distance no greater than the allowed tolerance. If tolerance = .o04 inch: .4“ or Less Over ,004“ 1 -4
37、 In Tolerance Out of Tolerance Figure 4 APPENDIX G. 1 Flatness Toierancing G. 1-2 in summary: deviations from flamess must be contained between two tangen- tial planes parallel to a baseline representing the ideal flat surface. The flatness tolerance limits the maximum distance between these planes.
38、 the baseline itself becomes identical with one of the two limiting planes: If deviations from perfect flamess lie entirely to one side of the bascline, then Plane 1 .) Plane Base= Plane 1 Plane 2 Plane 2 Plane 2 Figure 5 The extruded flatness tolerance tables in Aluminum Standards and Data are il-
39、lustrated, for simplicty and clarity, with shapes displaying concave deviations from flamess. But it does not matter whether the fiat surface has a concave deviation that dips “inside“ the ideai shape of the solid metal or a convex deviation that bulges “outside“ the ideai shape. The principle is th
40、e same: the deviation is measured fmm the baseline con- necting the ends of the tolerand width, see Figure 6. Flatness Toierans for Solid and Semihollow Shapes hollow shapes are given in ASD Table 11.6. The flamess tolerances for surfaces of extruded bar, solid shapes and semi- TABLE 11.6 Flatness (
41、Flat Surfaces)o BAR, SOLID SHAPES AND SEMIHOLLOW SHAPES EXCEPT FOR SHAPES IN O. T3510.14510, T651O.l76510 and Ta510 TEMPERS3 SURFACE WIDTH In. upm 1 1mniS.oOS In any 1 in. of mdM TOLERANCE-ln. Concave deviation *- Convex deviation from flames Figure 6 Note tha thxee tolerances are imposed: a minimum
42、 tolerance for surfas no wider than one inch; a total tolerance over the entire width; and a unit tolerance in any one inch of width. STD-AA SUP-1-ENGL 1995 Ob04500 OOLB79L 333 D APPENDIX Flatness: Narrow Surfaces 6.4-1 Narrow-Surface Flatness Tolerance able 1 1.6 allows a deviation from perfect fla
43、mess of up to .o04 inch on any width up through 1.ooO inch. This means, for example, that a surface 0.5 inch wide is allowed a flat- T ness deviation of .o04 inch; so is a surface 0.8 inch wide, or 1. inch wide - or any other width less than one inch To put it ather way, a surface is aiiowed 0.004 i
44、nch flamess deviation regardiess of its specific width, as long as that width is no greater than one inch. STD-AA SUP-L-ENGL 1775 I Oh04500 0038772 27T - APPENDIX Flatness: Total-Width Tolerance 6.5-1 Total- Width Flatness Tolerance able 11.6 allows a total maximum deviation from flatness of: 0.004
45、T inch times the width of the surface in inches. The baseline for this measurement is the straight line wmecting the extreme ends of the toler- anced surface. This applies u) surfaces wider than one inch but not wider than 5.999 inches. For example, a surface 2.000 inches wide may deviate around its
46、 full- width baseline by no more than a total of -008 inch (2.000 x .OW = -008). See Figure 1. .008 Max. Boseline zky total tolerances on surfaces more than one inch up to 5.999 inches wide; and unit tolerances on any one-inch increment of width. imum thickness of the metal which forms the surface.
47、ness tolerances are: But they divide these tolerances into two classes, depending on the min- If the metai has a minimum thickness no larger than O. 187 inch, the flat- 0.006 inch minimum on surfaces up to one inch wide. 0.006 inch times total width (up to 5.999 inches) for total tolerance. 0.006 in
48、ch deviation in any single inch of width. If the metal has a minimum thickness of 0.188 inch or more, the flatness tolerances are the same as those of solid shapes: 0.W inch minimuin. 0.004 times width, total. 0.004 inch deviation in any single inch of width. STD.AA SUP-1-ENGL 1995 m Ob04500 OOL8795
49、 T9 - APPENDIX 1 H. 1 1 Straightness H.1-1 Straightness Tolerancing tandard straightness tolerances place limits on the samount of bow or waviness that is acceptable in an exuuded product. ASD Straightness Tolerancing Tables 11.4, and 12.8 are illustrated with e example of a Single curvahife, or bow, over the entire length of an extrusion. RigM Wrong Figure 1 Wrong As shown in Figure 1, the tolerance is applied and measured while the extrusion rests on its two ends, on a surface known to be accurately flat, and the “bow“ is min
