AA 18-2008 Standards for Aluminum Sand and Permanent Mold Castings (FIFTEENTH EDITION)《砂型铝及永久模铸造标准》.pdf

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1、Standards For Aluminum Sandand Permanent Mold CastingsTHE ALUMINUM ASSOCIATION CASTING STANDARDS PROGRAMAluminum permanent mold and sand castings are widely used in all types of applications due to aluminums exceptional characteristics and the great design flexibility inherent in these two casting p

2、rocesses.Historically, foundries each used their own individual standards covering the various aspects of permanent mold and sand castings. As new techniques and molding materials became available, they also contributed to further variations. The variations in that information, along with the lack o

3、f data in many areas, indicated the need for reliable and realistic criteria to which castings could be consistently produced. These criteria would provide all persons involved in the procurement of castings with an instrument by which they could expect foundries to base proposals and produce castin

4、gs to a specific quality level.Therefore, The Aluminum Association, as a service to the customers of the industry, prepared this guide for designers, engineers, buyers and production personnel as to the most economical use of the permanent mold and sand casting processes. This guide has two chapters

5、 each of which contains a series of product standards: E Series, Engineering Standards and M Series, Metallurgical Standards and Data.Dimensions, tolerances and other quantities expressed in both U.S. customary and Metric units in these standards are not necessarily identical due to rounding practic

6、es used by the committee.These Product Standards are not intended to be limiting in any way but rather they are expected to provide a measure of optimum conditions for the most economical use of the processes included and to provide consistency in terminology and definition, thereby resulting in a b

7、etter understanding between supplier and user. The use of these standards by any member or nonmember of The Aluminum Association is voluntary and issuance or existence of these standards does not in any respect prevent or restrict any member or nonmember from manufacturing or supplying products not

8、in conformance with these standards.As all published material is subject to change as new experience is gained, it is suggested that the data contained herein be verified with The Aluminum Association if there is any doubt as to their current validity.FIFTEENTH EDITIONJULY 2008This issue supersedes

9、all prior issues. Copyright 2008, The Aluminum Association, Inc.Unauthorized reproduction by photocopy or any other method is illegal.PREFACE 1-1 CHAPTER 1, ENGINEERING SERIES (E) PageE-1 LINEAR TOLERANCESOne Side of Parting Line 1-4E-2 LINEAR TOLERANCESAcross Parting Line 1-5E-3 LINEAR TOLERANCESCo

10、red Areas; Sand and Moving Parts 1-6E-4 DRAFT REQUIREMENTS AND INTERPRETATION 1-7E-5 FLATNESSSTRAIGHTNESS 1-9E-6 HOLES AND POCKETSSand Cast 1-10E-7 HOLES AND POCKETSPermanent Mold 1-11E-8 PROFILE TOLERANCE 1-12E-9 EJECTOR PIN MARKS 1-15E-10 FLASH REMOVALSnagging, Grinding, Removal of P/L, Chill Mark

11、s, Gates and Risers 1-16E-11 ANGULARITY - PERPENDICULARITY - PARALLELISM 1-17E-12 CONCENTRICITY 1-21E-13 MACHINE FINISH ALLOWANCE 1-24E-14 POSITIONAL TOLERANCE 1-25E-15 WALLS, FILLETS Sand and Moving PartsENGINEERING SERIES (E)NOTE: The values shown herein represent normal production practice at the

12、 most economic level. Greater accuracy involving extra close work or care in production should be specified only when and where necessary since additional costs may be involved. Conversely, more liberal values should be indicated, when acceptable, as these tend to keep costs to a minimum. Any variat

13、ions in these values shall not be binding on the foundry unless accepted in writing.The use of sand and/or metal cores broaden the design flexibility of sand and permanent mold castings by allowing a hole or undercut to be produced in a surface of a casting perpendicular to the parting plane. Since

14、these cores are separate from the sand or metal mold there must be a clearance allowance for placement or movement. Such allowances create an added variation in dimensions of a surface produced by the core to a surface produced by the mold. The amount of this additional tolerance is governed by the

15、projected area of the core.ADDITIONAL TOLERANCE, in., mmProjected AreaSand Mold Sand CorePM to Sand CorePM to Metal Corein.2cm2in.2cm2in. mm in. mm in. mmUp thru 10 65 .020 0.50 .015 0.38 .010 0.25Over 10 65 thru 50 320 .035 0.90 .025 0.60 .015 0.38Over 50 320 thru 100 650 .045 1.10 .030 0.80 + .015

16、 0.38Over 100 650 thru 250 1600 .060 1.50 .040 1.00 + .022 0.60Over 250 1600 thru 1000 6500 .090 2.30 .060 1.50 + .032 0.80For over 1000 in.2(6500 cm2) of projected area, consult foundry.NOTE: The above tolerances are to be added to those determined for a dimension as provided in Standards E1 and E2

17、. Dimensions wholly within the area of a single core need not have this tolerance added; linear tolerance, only, would apply.*Formerly AA-CS-E3-92 in previous editions 1-7Standards For Aluminum Sandand Permanent Mold CastingsNOTE: The values shown herein represent normal production practice at the m

18、ost economic level. Greater accuracy involving extra close work or care in production should be specified only when and where necessary since additional costs may be involved. Conversely, more liberal values should be indicated, when acceptable, as these tend to keep costs to a minimum. Any variatio

19、ns in these values shall not be binding on the foundry unless accepted in writing. The molding process, the overall casting size and configuration need also be considered when specifying draft requirements.All walls on castings that are perpendicular to the parting plane require draft or taper. This

20、 draft is not constant. It will vary with the length of draw (L). See sketches below and graph on Page 2 which applies to all surfaces except cored holes and pockets.E4* DRAFT REQUIREMENTS Page 1 of 2Normally the drawing does not show draft (Figure 1). Standard foundry practice is to add draft to th

21、e part. To avoid misunderstanding, this is synonymous with saying it will add metal to the casting, thereby increasing its size and weight.Draft “d” will be added to “A”, increasing its size to “A1”. Note that added draft affects dimension “B” by decreasing its size to “B1”. This is shown in Figure

22、2.Draft may be removed if desired but must be specified on drawing, as shown in Figure 3.In holes, draft will be added to “a” decreasing its size to “a1”; see Figure 4. When the designer desires a hole dimension to become larger for reasons such as clearance, he should so indicate.The direction in w

23、hich draft is applied is governed by the location of the parting line and will be at the foundrys option unless otherwise specified; see Figure 5.When a parting line interrupts a surface to which draft is applied, the amount of draft to be added will be determined by the longer portion of surface to

24、 be drawn. Drafts will be applied to the remainder of the surface to provide a match at the parting line; see Figure 6.ENGINEERING SERIES (E)Fig. 1 Fig. 2Fig. 3Fig. 4Fig. 5 Fig. 6*Formerly AA-CS-E4-92 in previous editions 1-8Standards For Aluminum Sandand Permanent Mold CastingsENGINEERING SERIES (E

25、)NOTE:Figures shown in degrees are recommended angular draft for a given length of draw.E4* DRAFT REQUIREMENTS Page 2 of 2*Formerly AA-CS-E4-92 in previous editions 1-9Standards For Aluminum Sandand Permanent Mold CastingsENGINEERING SERIES (E)NOTE: The values shown herein represent normal productio

26、n practice at the most economic level. Greater accuracy involving extra close work or care in production should be specified only when and where necessary since additional costs may be involved. Conversely, more liberal values should be indicated, when acceptable, as these tend to keep costs to a mi

27、nimum. Any variations in these values shall not be binding on the foundry unless accepted in writing.FLATNESS: Flatness is that condition which exists when all points on a surface lie in the same plane. The surfaces of castings can be measured for flatness by supporting the surface in question on th

28、ree widely separated points to establish the basic plane. The flatness variation is the deviation from that plane as measured by mutually accepted methods.FLATNESS TOLERANCE: A flatness tolerance is that total deviation permitted from a plane and consists of the distance between two parallel planes

29、within which the entire surface so toleranced must lie.E5*FLATNESS- STRAIGHTNESS-Greatest Dimension Permanent Mold Tolerance Sand Tolerancein. mm in. mm in. mm0 thru 6 150 within 0.020 within 0.50 within 0.030 within 0.80each additional 1 thru 24 25 thru 600 0.003 per inch 0.08 per 25 mm 0.003 per i

30、nch 0.08 per 25 mmFor castings over 24 inches (600 mm), consult foundry.Checking for flatness will be performed only on those surfaces specified.On castings of such configuration and/or alloy where it becomes impossible or impractical to straighten, exceptions to the above tolerances are required. I

31、n such cases the foundry should be consulted.Tolerances closer than the above can at times be obtained. Special gauges and fixtures requiring extra costs may be needed.STRAIGHTNESS: Straightness is that condition which, when matched with a true straight edge of a true flat surface, will permit full

32、line contact along the full length. Tolerance should be discussed with foundry.*Formerly AA-CS-E5-92 in previous editions 1-10Standards For Aluminum Sandand Permanent Mold CastingsENGINEERING SERIES (E)NOTE: The values shown herein represent normal production practice at the most economic level. Gre

33、ater accuracy involving extra close work or care in production should be specified only when and where necessary since additional costs may be involved. Conversely, more liberal values should be indicated, when acceptable, as these tend to keep costs to a minimum. Any variations in these values shal

34、l not be binding on the foundry unless accepted in writing.E6* HOLES AND POCKETSSAND CASTHoles and pockets in sand castings may be produced either by incorporation as integral features of the pattern equipment (provided size limitations, draft requirements and direction of draw are satisfactory), or

35、 by insertion of separately made sand cores. These sand cores will give a flexibility of design to the pattern equipment (see figure above), but generally at a higher production cost.The limiting factors in casting holes and pockets are depth, degree of draft and the narrowest dimension across the h

36、ole.The table below lists limiting sizes, depths and drafts for holes as produced with or without separate sand cores. Note that as in the above figure, “a” refers to the shortest dimension across the base of the hole or pocket.a BaseHole diameter or Minimum dimension of recess in., mmin. mm in. mm

37、in. mm in. mm in. mm0.25 6 0.50 12 1.0 25 2.0 50 4.0 100L Maximum Depth, in., mmSand Mold Solid Solid 0.50 12 0.75 19 1.50 38 2.0 50Sand Core Solid Solid 0.50 12 2.0 50 4.0 100 8.0 200d Draft Required Per Side, Deg.Sand Mold 10 10 10 10 7 7 5 5Sand Core Same as Standard E4 for Sand Castings*Formerly

38、 AA-CS-E6-2000 in previous editions 1-11Standards For Aluminum Sandand Permanent Mold CastingsENGINEERING SERIES (E)NOTE: The values shown herein represent normal production practice at the most economic level. Greater accuracy involving extra close work or care in production should be specified onl

39、y when and where necessary since additional costs may be involved. Conversely, more liberal values should be indicated, when acceptable, as these tend to keep costs to a minimum. Any variations in these values shall not be binding on the foundry unless accepted in writing.E7*HOLES AND POCKETSPERMANE

40、NT MOLDHoles and pockets in permanent mold castings are preferably produced by steel cores which are so incorporated in the mold design that they can be withdrawn manually or mechanically during the casting cycle. Such cores require draft for withdrawal.Sand cores may be used where normal draft cann

41、ot be tolerated, or where internal chambers are required which do not permit withdrawal of steel cores. Thus modified, the process is known as “Semi-permanent” mold.In special circumstances steel cores may be collapsed and removed in sections to accomplish a similar result. Loose pieces can be used

42、to form undercuts or provide non-drafted surfaces. In such cases consultation with the foundry is advisable.The table below gives desired values for core depths and drafts in relation to diameters.BaseHole diameter or Minimum dimension of recess in., mmin. mm in. mm in. mm in. mm in. mm0.25 6.0 0.50

43、 12.0 1.00 25.0 2.00 50.0 4.00 100.0Maximum Depth, in., mmPermanent Core 0.25 6 1.0 25 2.0 50 4.0 100 8.0 200Sand Core Solid Solid 0.50 12 2.0 50 4.0 100 8.0 200Draft Required Per Side, Deg.Permanent Core 10 10 7 7 5 5 3 3 3 3Sand Core Same as Standard E4 for Sand Castings*Formerly AA-CS-E7-2000 in

44、previous editions 1-12Standards For Aluminum Sandand Permanent Mold CastingsENGINEERING SERIES (E)NOTE: The values shown herein represent normal production practice at the most economic level. Greater accuracy involving extra close work or care in production should be specified only when and where n

45、ecessary since additional costs may be involved. Conversely, more liberal values should be indicated when acceptable, as these tend to keep costs to a minimum. Any variations in these values shall not be binding on the foundry unless accepted in writing.A profile is the outline of an object in a giv

46、en plane. Profiles are formed by projecting a three-dimensional figure onto a plane or by taking cross sections through the figure. The elements of a profile are straight lines, arcs, and other curved lines.The profile tolerance specifies the width of a uniform zone (one half on each side of the bas

47、ic profile) within which the elements of the surface must lie.Where applicable, a general profile tolerance requirement may be specified in a note on the drawing. The general profile tolerance should specify the datum system (usually defined by datum target pointsSee AA-CS-E20-92, Page 32) from which the basic profile of the toleranced surfaces are located. (Figure 1)In determining the amount of tolerance to be specified in a general profile tolerance requirement, consideration must be given to a number of factors. The general profile toleran