1、October 2011 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).IC
2、S 77.140.50!%(y“2058604www.din.deDDIN 6932Design rules for stamped steel parts,English translation of DIN 6932:2011-10Gestaltungsregeln fr Stanzteile aus Stahl,Englische bersetzung von DIN 6932:2011-10Rgles de dveloppement pour pices dcoupes et embouties en acier,Traduction anglaise de DIN 6932:2011
3、-10SupersedesDIN 6932:2010-01www.beuth.deDocument comprises 18 pagesIn case of doubt, the German-language original shall be considered authoritative.09.13 DIN 6932:2011-10 2 A comma is used as the decimal marker. Contents Page Foreword . 3 1 Scope . 4 2 Normative references . 4 3 General rules . 4 4
4、 Design rules 4 4.1 General . 4 4.2 Design rules for cut parts 4 4.2.1 Basic principles 4 4.2.2 Shape of pierced holes 5 4.2.3 Hole diameter 5 4.2.4 Notching 6 4.2.5 Piercing and notching on one side . 6 4.2.6 Curvatures . 6 4.2.7 Curvatures on strip lengths . 6 4.2.8 Distances . 7 4.2.9 Oblique cut
5、ting 7 4.2.10 Positioning guard . 8 4.3 Design rules for bent parts 8 4.3.1 Basic principles 8 4.3.2 Bending radii . 8 4.3.3 Internal radius/External radius 8 4.3.4 Preparation for bending . 9 4.3.5 Minimum leg length 10 4.3.6 Minimum distance from the bending axis 11 4.3.7 Relief holes 11 4.4 Desig
6、n rules for deep-drawn parts . 11 4.4.1 General . 11 4.4.2 Earing . 11 4.4.3 Radii of curvature . 12 4.4.4 h/d ratio 12 4.4.5 Buckling/Wrinkling . 13 4.4.6 Bottom flatness . 13 4.4.7 Material elongation/Material thickening . 14 4.4.8 Box-shaped deep-drawn parts 14 4.4.9 Plunging . 15 5 Dimensioning
7、15 Annex A (informative) Explanatory notes 17 Bibliography . 18 DIN 6932:2011-10 3 Foreword This standard has been prepared by Working Committee NA 026-00-03 AA Stanzteile of the Normenausschuss Federn, Stanzteile und Blechformteile (NAFS) (Springs, Stamped Parts and Moulded Parts Standards Committe
8、e). For more information on NAFS, visit our website at www.nafs.din.de. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for identifying any or all such patent rights. Amendments This standard diff
9、ers from DIN 6932:2010-01 as follows: a) normative references have been updated; b) Figure 4 in 4.2.4 “Notching” has been deleted; c) Figure 14 illustrating “Relief holes” has been revised; d) figures have been provided with titles; e) the standard has been editorially revised. Previous editions DIN
10、 6932: 1983-01, 2010-01 DIN 6932:2011-10 4 1 Scope The purpose of this standard is to provide designers with guidance on the correct design of steel stampings and to draw attention to process-related problems. 2 Normative references The following referenced documents are indispensable for the applic
11、ation of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. DIN 250, Radii DIN 6935, Cold bending of flat rolled steel DIN 7952-1, Sheet metal anchorage with threads Dimensions
12、 3 General rules 3.1 To properly design stampings, it is essential to have information on the production and subsequent processing of the part as well as on the material to be used. It is therefore often advisable to consult production specialists regarding the design of such parts and the choice of
13、 suitable material. 3.2 Appreciable savings of material are possible in stamping by choice of a favourable design. 3.3 In some cases it is more economical to produce complex-shaped parts by joining several simple-shaped stampings (e.g. by welding, riveting, adhesive bonding). 3.4 The starting materi
14、al should preferably be flat steel stock of specified material properties, dimensions and tolerances. In choosing the material, its suitability for the intended production process is also to be examined. 3.5 The stiffness of stampings can be improved by beading. 4 Design rules 4.1 General The follow
15、ing clauses of this standard specify basic rules for the design of stampings. Divergence from these rules generally leads to an increase in manufacturing costs and should, therefore, be considered only if the particular application of the part renders it necessary. In such cases, joint consultation
16、between the designer and the production specialists is advisable. The distinction drawn below between design solutions to be preferred or avoided is to be understood in terms of production process simplification and/or manufacturing costs. 4.2 Design rules for cut parts 4.2.1 Basic principles The de
17、sign of cut parts shall take into account the fact that cut surfaces always have a drawn-in band and a break band with a burr (see Figure 1). This results in hole dimensions always being larger on the break band side than on the drawn-in side (see Figure 2). DIN 6932:2011-10 5 The difference between
18、 d1and d2or l1and l2depends on the material, the clearance between punch and die and the thickness s of the flat product. If the use of the part renders it necessary, the side of the drawn-in or break band (i.e. side of the burr) shall be indicated in the drawing. Key 1 Height of cut surface 2 Drawn
19、-in band 3 Cut band 4 Break band 5 Burr height 6 Side of the break band Figure 1 Representation of a cut surface Figure 2 Comparison of drawn-in band side and break band side dimensions (notation) NOTE The position of the burr side can be decisive during the further processing of the steel into form
20、ed and bent parts. If the burr side is stretched during forming and bending, cracking is more likely to occur there than on the punch entry side. 4.2.2 Shape of pierced holes Round holes are the simplest to produce and should, therefore, be preferred. 4.2.3 Hole diameter The diameter d of a hole sha
21、ll not exceed the thickness s of the flat product. (see Figure 3). The following rule applies: d s DIN 6932:2011-10 6 a) to be preferred b) to be avoided Figure 3 Ratio of diameter to product thickness (notation) 4.2.4 Notching For the width b of notches, the following rule applies: b s, where s is
22、the thickness of the flat product. For depth l, the following rule applies: l s, where s is the thickness of the flat product. NOTE See also Annex A for problems associated with the depth l of notches. Notches are to be bevelled, if possible, and their corners rounded. 4.2.5 Piercing and notching on
23、 one side With long stampings, distortion is likely to occur if piercing or notching is carried out at close regular intervals on one side near the edge. Figure 4 Distortion of holes and notches on one side 4.2.6 Curvatures For curvatures, radii specified according to DIN 250 shall be used. 4.2.7 Cu
24、rvatures on strip lengths For radiused ends on lengths of strips, the radius of curvature r should be greater than half of the strip width b. (See Figure 5.) The following rule applies: r b/2 DIN 6932:2011-10 7 a) to be preferred b) to be avoided Figure 5 Radiused lengths of strip (notation) 4.2.8 D
25、istances For the distance from the edge and distances between features, the rule a 2 s applies. Examples of varying edge distances and distances between features in a cut part are shown in Figure 6. Figure 6 Distance from the edge and between features (Examples) (notation) 4.2.9 Oblique cutting Hole
26、s and cut surfaces at an oblique angle to the surface of the workpiece shall be avoided (see Figure 7). a) to be preferred b) to be avoided Figure 7 Parts with cuts at an oblique angle (Examples) DIN 6932:2011-10 8 4.2.10 Positioning guard To avoid confusion between the cuts for mirror-image parts,
27、it is practicable to provide a positioning guard. EXAMPLE Positioning guard for subsequent bending (see Figure 8). Key 1 Positioning guard 2 Intended bending line Figure 8 Positioning guard for subsequent bending 4.3 Design rules for bent parts 4.3.1 Basic principles Bending always leads to changes
28、in the cross section of the bending zone of the flat product. The extent of this change in cross section increases as the bending radius relative to the thickness of the flat product decreases. As the flat product also always undergoes elastic deformation during bending, the bent part will tend to s
29、pring back, with the amount of spring-back increasing as the ratio r : s increases. Depending on the chosen bending procedure, marks resulting from the action of the bending equipment cannot be avoided. 4.3.2 Bending radii As a general rule, bending radii should be as large as possible. See DIN 6935
30、 for minimum bending radii. In free bending, a geometrically exact shape of radius can only be approximately obtained. 4.3.3 Internal radius/External radius Owing to the deformation of the cross section of the flat product during bending, and with a given thickness s of the flat product and a given
31、internal radius r, the following relationship always applies: R r + s Figure 9 illustrates an example of the above. DIN 6932:2011-10 9 Figure 9 Deformation during bending (notation) The internal radius is to be stated when dimensioning. 4.3.4 Preparation for bending In the bending zone, both the thi
32、ckness of the flat product and the geometrical shape of the cross section change. Starting with a rectangular cross section, the following applies in the bending zone (see Figure 10): b1 b2 b Figure 10 Preparation for bending (notation) DIN 6932:2011-10 10 To avoid exceeding the width b in the finis
33、hed product, provision of relief notches at either end of the bending line as shown in Figure 11 is recommended. Figure 11 Relief notches (notation) 4.3.5 Minimum leg length When right-angled bending a flat product of thickness s, the minimum leg length h shall be as follows (see Figure 12): hmin= r
34、 + 2 s Figure 12 Minimum leg length (notation) DIN 6932:2011-10 11 4.3.6 Minimum distance from the bending axis Due to the deformation of the flat product in the bending zone, features shall maintain a minimum distance to the bending axis if these features are to keep their geometrical shape during
35、bending. For the minimum distance e, according to Figure 13, the following rule applies: emin= 2 s Figure 13 Minimum distance from the bending axis (notation) 4.3.7 Relief holes To prevent tearing/cracking of the workpiece for instance during lancing, the provision of relief holes as shown in Figure
36、 14 is recommended. Key 1 Relief holes Figure 14 Relief holes 4.4 Design rules for deep-drawn parts 4.4.1 General The wall thickness always changes in the forming zones of deep-drawn parts. The desired geometrical shape can only be approximately obtained. 4.4.2 Earing Earing is an unavoidable phenom
37、enon and increases with an increasing h/d ratio. DIN 6932:2011-10 12 Key 1 Earing Figure 15 Earing in deep-drawn parts (notation) 4.4.3 Radii of curvature The radii r of curvature shall be as large as possible. An illustrative example is given in Figure 16. The following rule applies: r 3 s Radii co
38、mplying with the specifications of DIN 250 shall be used. Figure 16 Radii of curvature (notation) 4.4.4 h/d ratio When designing cylindrical deep-drawn parts without a flange and with a height h and a diameter d, as shown in Figure 17, the following ratio should be kept within, if possible: h/d 0,4
39、The above ratio applies to deep drawing quality steel deep-drawn in a single operation. To obtain a larger h/d ratio, the operation shall be repeated several times. DIN 6932:2011-10 13 Figure 17 Ratio h/d (notation) 4.4.5 Buckling/Wrinkling When deep drawing in several operations, buckling in the cy
40、lindrical portion and wrinkling in the flange, associated with marked changes in dimensions can occur (see Figure 18). Figure 18 Buckling/wrinkling 4.4.6 Bottom flatness The bottom of a deep-drawn part can be expected to show a marked deviation in bottom flatness compared with that of the starting s
41、tock. DIN 6932:2011-10 14 4.4.7 Material elongation/Material thickening In deep-drawn parts as in Figure 19, the side wall becomes tapered as a result of elongation and area reduction of the steel while the flange becomes thicker due to material compression. s1s s3 s Figure 19 Material elongation/Ma
42、terial thickening (notation) 4.4.8 Box-shaped deep-drawn parts In the case of box-shaped deep-drawn parts with a radius of curvature of r = s it can be assumed that product thickness will be reduced to 0,7 s at the edges and to 0,5 s in the rounded corners (see Figure 20). Key 1 Sectional plane Figu
43、re 20 Box-shaped deep-drawn part (notation) Due to the risk of cracking associated with high degrees of deformation, particularly in the rounded corners of box-shaped deep-drawn parts, r s shall be used. DIN 6932:2011-10 15 4.4.9 Plunging The collar height of a hole formed by plunging according to D
44、IN 7952-1, shall not exceed half the diameter of the hole (see Figure 21). s1 s a) to be preferred b) to be avoided Key 1 Not flat without post-treatment Figure 21 Holes formed by plunging (Examples) (notation) 5 Dimensioning When assigning dimensions to the position of features in stampings, it is
45、advisable, if possible, to start out from a functional reference edge or reference point. Examples are shown in Figures 22 and 23. E.g. for groups of holes: Key 1 Dimensioning where distance from edge is important 2 Dimensioning where symmetry from the centre is important Figure 22 Dimensioning the
46、position of groups of holes DIN 6932:2011-10 16 E.g. for notches Key 1 Dimensioning where symmetry from the centre is important 2 Dimensioning where distance from edge is important Figure 23 Dimensioning the position of notches DIN 6932:2011-10 17 Annex A (informative) Explanatory notes In drafting
47、this standard, the Committee was guided by the following principles: The design rules are meant to reflect the current state of the art in stamping technology. This does not exclude the possibility that by applying highly developed tools or technologies higher production standards (smaller holes, sm
48、aller bending radii, oblique-angled cuts etc.) can be obtained. This standard, however, does not cater for these situations. In some examples, problems which can arise in the production of stampings are indicated. In many cases, these can be overcome by special technical measures. However, it was no
49、t intended to describe these measures, which usually add to the technical complexity of the manufacturing process, in this standard - a fact that has been referred to in Clause 3. Hence and above all, it is the primary aim of this standard to give guidance on the cost-effective production of stampings. Thus, its main intention is to give designers a feel for the characteristic features of stamping and to assist them in reconciling functional and technological requirements in stamping production. In their discussion of
