1、BRITISH STANDARD BS 6979:1989 Incorporating Amendment No.1 Method for Measurement of static deflection of power presses UDC 621.042:621.979:620.174.22+621.3.082.12BS6979:1989 This British Standard, having been prepared under the directionof the Machine, Engineers and Hand Tools Standards Committee,
2、was published under the authority ofthe Board of BSI and comesintoeffect on 31March1989 BSI 12-1999 The following BSI references relate to work on this standard: Committee reference MTE/1 Draft for comment 87/72928 DC ISBN 0 580 16806 9 Committees responsible for this British Standard The preparatio
3、n of this British Standard was entrusted by the Machine, Engineers and Hand Tools Standards Committee (MTE/-) to Technical Committee MTE/1, upon which the following bodies were represented: Advanced Manufacturing Technology Research Institute Cranfield Institute of Technology Department of Trade and
4、 Industry (Mechanical Engineering and Manufacturing Technology Division) Health and Safety Executive Institution of Production Engineers Machine Tool Trades Association Ministry of Defence Society of British Aerospace Companies Limited University of Aston in Birmingham The following bodies were also
5、 represented in the drafting of the standard, through sub-committees and panels: Institute of Sheet Metal Engineering Metalforming Machinery Makers Association Limited Amendments issued since publication Amd. No. Date of issue Comments 6296 May 1990 Indicated by a sideline in the marginBS 6979:1989
6、BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Measuring equipment 1 4 Test conditions 4 5 Procedure 4 6 Test report 4 Appendix A Typical format of test report for user 8 Appendix B Typical format for record of measurements for retention
7、 by manufacturer 10 Figure 1 Directions of the axes 1 Figure 2 Typical measuring equipment 2 Figure 3 Bolster measuring plate and additional discs 3 Figure 4 Position of dial gauges 4 Table 1 Dimensions of bolster measuring plates and additional discs 3 Table 2 Deflection tests 5 Publications referr
8、ed to Inside back coverBS6979:1989 ii BSI 12-1999 Foreword This British Standard has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Committee and is based on EPPMP Recommendation5, prepared by the European Power Press Manufacturers Panel (EPPMP). The EPPMP is a
9、voluntary organization of which the membership is comprised of machine tool manufacturers associations of a number of West European countries. Although the method is mainly applicable to power presses of mechanical open front type with capacities up to and including2500kN, it may also be applied to
10、straight sided and hydraulic presses and to presses with capacities over2500kN. Capacity ratings, dimensions and definitions of power presses are given inBS6590. Accuracy requirements and geometrical and practical tests are given in BS4656-34. A British Standard does not purport to include all the n
11、ecessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, page
12、s1to16, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS 6979:1989 BSI 12-1999 1 1 Scope This British Standard describes a method for measuri
13、ng the deflection of power presses under static conditions. Permissible values for deflection are not given. For reasons of simplicity the diagrams in this standard illustrate only typical machines. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover.
14、2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 x (-axis) the axis parallel to the lower tool face (upper surface of bedplate) of the press, running from front to back 2.2 y (-axis) the axis parallel to the lower tool face of the press, running from right
15、 to left 2.3 z (-axis) the vertical axis coinciding with the centre line of the fixing pin hole in the unloaded press NOTESeeFigure 1 for directions of the axes. 3 Measuring equipment NOTE 1The measuring equipment may be designed in various ways; seeFigure 2 for examples. The measuring equipment sha
16、ll fulfil the following requirements. a) As far as possible no torque and/or horizontal force shall be transmitted to the ram. b) The bolster measuring plates and additional discs (seeFigure 3) shall be selected from different size ranges depending on the nominal capacity of the press (seeTable 1).
17、c) The dimensions of the bolster measuring plate and additional discs shall give acceptable values of material compression and non-plastic deformation when using low carbon steel with minimum yield stress of300N/mm 2 . NOTE 2In order to avoid any deformation of the bed, a low carbon steel sheet shou
18、ld be placed between the bed and the measuring equipment. d) The measuring equipment shall be stable enough to ensure that it does not influence the measuring results. NOTE 3The modified fixing pin should be so designed that plastic deformation will not occur on slide surface. NOTE 4The rod for fixi
19、ng measuring equipment should be fastened to the bolster plate in such a way that the deflection during loading will be minimized. Figure 1 Directions of the axesBS6979:1989 2 BSI 12-1999 Figure 2 Typical measuring equipmentBS 6979:1989 BSI 12-1999 3 Table 1 Dimensions of bolster measuring plates an
20、d additional discs (seeFigure 3) All dimensions are in millimetres. Figure 3 Bolster measuring plate and additional discs Press capacity Bolster measuring plate diameters Additional disc diameters Measuring equipment d 1 d 2 d 3 d 4 d 5 d 6 kN mm mm mm mm mm mm 100 110 140 160 250 400 630 110 or 130
21、 140 or 170 150 230 800 1000 1250 1600 130 170 170 300 2000 2500BS6979:1989 4 BSI 12-1999 4 Test conditions 4.1 General Measurements are normally made on prototypes,i.e. one power press of each size in each range. Measurements are normally carried out on presses having standard bedplates with bed pl
22、ugs in position. On presses which are generally used without bedplates or with non-standard bedplates, similar tests may be carried out and these conditions stated in the test report (seeclause6). When measuring deflections of used presses, special attention should be paid to the correct location of
23、 the bedplate rings in the bedplate. 4.2 Preparation for test Before testing, set clearances in load transmission parts and in slide guides according to the manufacturers instructions. 5 Procedure 5.1 General During the test, position the crankshaft in its top position to reduce the effect of moveme
24、nt in the slide. Set the ram adjusting screw close to its middle position and the stroke adjustment at the maximum length. Set the slide counter-balance, where fitted, so as to balance the slide at top dead centre. Load the press to its full capacity and release three times before tests are carried
25、out. Where there is insufficient capacity of the hydraulic load cell, extrapolation to the nominal press force capacity (F N ) is permitted. The hydraulic load cell should in this case have a capacity of at least50% of the nominal press force. NOTETest load F N /3 at eccentricity b/6 is only calcula
26、ted for measuring purposes and should not be understood to be a manufacturers recommendation for practical use. 5.2 Application of tests Carry out tests as given inTable 2, according to the type of press as follows. Apply the following tests to open front presses and straight sided presses. Test D1
27、Angular deflection () front to back and height of intersection point (B) at concentric loading. Test D2 Spring constant (C). Test D3 Maximum bedplate deformation (Z N ). Test D4 Angular deflection( ) right to left at eccentric loading. Apply the following tests to straight sided presses, in addition
28、 to testsD1toD4. Test D5 Angular deflection ( ) right to left and height of intersection point (A) at concentric loading. Test D6 Angular deflection ( ) front to back at eccentric loading. 5.3 Position of dial gauges Position dial gauges as shown inFigure 4. NOTE 1It is most important that the dial
29、gauges are placed as close as possible to the centre plane of the press,i.e. the x-z plane for those on the x-axis and the y-z plane for those on the y-axis. NOTE 2Readings on the dial gauges are represented byZ 11andZ 12for test D1,Z 21andZ 22for testD2, etc. as shown inFigure 4 and given inTable 2
30、. 6 Test report The test report shall contain the information given in columns6 and7 ofTable 2. If tests have been carried out on presses generally used without bedplates or with non-standard bedplates, this shall be stated in the test report (see4.1). NOTEA typical format in which the test report m
31、ay be presented to the user is given inAppendix A. A typical format in which the test results may be recorded for retention by the manufacturer is given inAppendix B. NOTEPosition of dial gauges is represented by“x”. Figure 4 Position of dial gaugesBS 6979:1989 BSI 12-1999 5 Table 2 Deflection tests
32、 NOTEDimensions L 1toL 6are in metres. Dial gauge readings are in millimetres. 1 2 3 4 5 6 7 No. Diagram showing application of load F and position of dial gauges Object Observations Formulae Graph Result record D1 Angulardeflection front to back Height of intersection point B (mm) at concentric loa
33、ding measured at half nominal capacity and nominal capacity L 1 L 2 Dial gauges set to zero atF N/4 kN Read off gauges Z 11 , Z 12 , X 13at F N/2and atF N NOTESpecial attention should be paid to the+ or signs on the gauges. N/2 NB N/2 (mm) B N (mm) D2 Spring constant Dial gauges set to zero at F 0 =
34、0kN Read off gauges Z 21 , Z 22atF N/4and at four steps up to F N , or to max. force of hydraulic load cell mm m - mm m - mm m - C kN mm - C kN mm - BS 6979:1989 6 BSI 12-1999 Table 2 Deflection tests NOTEDimensions L 1toL 6are in metres. Dial gauge readings are in millimetres. 1 2 3 4 5 6 7 No. Dia
35、gram showing application of load F and position of dial gauges Object Observations Formulae Graph Result record D3 Maximum bedplate deformation at Z 31 (mm) Z 32 (mm) Z 33 (mm) Z 34 (mm) Dial gauges set to zero at F N/4 kN Read off gauges Z 31 , Z 32 , Z 33 , Z 34atF N Z N 31 (mm) Z N 32 (mm) Z N 33
36、 (mm) Z N 34 (mm) D4 Angular deflection right to left at eccentric loading L 3 e = b/6 Dial guages set to zero atF N/4 kN Read off gauges Z 41 , Z 42atF N/3 e (mm) F N/3 (kN) mm m - mm m - BS 6979:1989 BSI 12-1999 7 Table 2 Deflection tests NOTEDimensions L 1toL 6are in metres. Dial gauge readings a
37、re in millimetres. 1 2 3 4 5 6 7 No. Diagram showing application of load F and position of dial gauges Object Observations Formulae Graph Result record D5 Angular deflection right to left Height of intersection point A (mm) at concentric loading measured at half nominal capacity, and nominal capacit
38、y L 4 L 5 Dial gauges set to zero at F N/4 kN Read off gauges Z 51 , Z 52 , X 53atF N/2and atF N NOTESpecial attention should be paid to the+ or signs on the gauges. A N/2 (mm) A N (mm) D6 Angular deflection front to back at eccentric loading L 6 e = t/6 Dial gauges set to zero at F N/4 kN Read off
39、gauges Z 61 , Z 62atF N/3 e (mm) F N/3 (kN) mm m - N/2mm m - Nmm m - mm m - mm m - BS6979:1989 8 BSI 12-1999 Appendix A Typical format of test report for userBS 6979:1989 BSI 12-1999 9BS6979:1989 10 BSI 12-1999 Appendix B Typical format for record of measurements for retention by manufacturerBS 6979
40、:1989 BSI 12-1999 11BS6979:1989 12 BSI 12-1999BS 6979:1989 BSI 12-1999 13BS6979:1989 14 BSI 12-1999BS 6979:1989 BSI 12-1999 15BS6979:1989 16 BSI 12-1999BS 6979:1989 BSI 12-1999 Publications referred to BS 4656, Accuracy of machine tools and methods of test 1) . BS 4656-34, Specification for power pr
41、esses, mechanical open front type. BS 6590, Specification for capacity ratings and dimensions of power presses, mechanical open front type 1) . 1) Referred to in the foreword only.BS 6979:1989 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national bod
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