1、BRITISH STANDARD BS 1983-5: 1989 Incorporating Amendment No. 1 Chucks for machine tools and portable power tools Part 5: Code of practice for the safe operation of workholding chucks used on lathes UDC 621.9.022-229.323:62-783.67:62-5:621.941:614.8:006.76BS1983-5:1989 This British Standard, having b
2、een prepared under the directionof the Machine, Engineers and Hand Tools Standards Committee, was published under the authority of the Board of BSI and comes intoeffect on 31August1989 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference MTE/1 Draft for c
3、omment 84/77942 DC ISBN 0 580 16961 8 Committees responsible for this British Standard The preparation 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 M
4、anufacturing Technology Research Institute Cranfield Institute of Technology Department of Trade and Industry Mechanical Engineering and Manufacturing Technology Division (Mmt) Federation of British Engineers Tool Manufacturers Health and Safety Executive Institution of Production Engineers Ministry
5、 of Defence University of Aston in Birmingham The following body was also represented in the drafting of the standard, through subcommittees and panels: Portable Electric Tool Manufacturers Association Amendments issued since publication Amd. No. Date of issue Comments 6664 November 1990 Indicated b
6、y a sideline in the marginBS1983-5:1989 BSI 09-1999 i Contents Page Committees responsible Inside front cover Foreword iii 1 Scope 1 2 Chuck grip 1 2.1 General 1 2.2 Forces applied to the chuck 1 2.3 Change of grip at speed 13 2.4 Achieving the required grip 16 2.5 Flexible workpieces 16 3 Maximum s
7、peed of the chuck 16 4 Balancing 17 5 Inertia loading imposed on the drive 18 6 Gravitational and cutting forces: effect on the machine 20 7 Other aspects ofthesafe operation of lathe chucks 20 7.1 Chuck keys 20 7.2 Gross overspeeding 20 7.3 Adaptors 21 7.4 Mounting bolts for chuck body 21 7.5 Mount
8、ing bolts for jaws 21 7.6 Jaw materials 21 7.7 Dissipation of kinetic energy 21 7.8 Stroke detectors 21 7.9 End of bar detectors 21 8 Summary of the responsibilities of machine tool manufacturer, chuck manufacturer and user 21 Appendix A Estimation of power available at the cutting zone 23 Appendix
9、B Radial stiffness and out-of-roundness of ring held in jaws 23 Appendix C Measurement of the inertia of irregular components 25 Appendix D Worked example 41 Figure 1 External forces: horizontal spindle, overhung workpiece 26 Figure 2 External forces: vertical spindle 26 Figure 3 External forces: in
10、clined slide 27 Figure 4 Feed rate v. torque factor C s : drilling 28 Figure 5 Feed rate v. feed force factor F s1(for drills up to 16 mm diameterinsteel and cast iron and for all drill sizes in brass and aluminium) 29 Figure 6 Feed rate v. feed force factor F s1(for drills 16 mm diameterandlarger,
11、in steel and cast iron) 30 Figure 7 Multiplying factors when tailstock centre is used 31 Figure 8 Typical curve showing change of grip with speed 32 Figure 9 “Standard” jaw positions 33 Figure 10 Calculation of change of grip at speed 34 Figure 11 Calculation of change of grip at speed: flexible wor
12、kpieces 35 Figure 12 Graph of change of grip v. stiffness ratio for a flexible workpiece 36 Figure 13 Maximum residual specific unbalance 37 Figure 14 Typical output from a velocity transducer (mounted transversely on a headstock) 38BS1983-5:1989 ii BSI 09-1999 Page Figure 15 Loads applied to spindl
13、e 39 Figure 16 Clamping on to a thin ring: multiple jaws 40 Figure 17 Trifilar suspension 41 Figure 18 Sketch of component 43 Figure 19 Permitted mass x eccentricity v. spindle speed 44 Figure 20 Inertia load permitted 45 Figure 21 Lathe spindle data 46 Figure 22 Chuck: leading dimensions and data 4
14、7 Figure 23 Change of grip with speed (external grip) 48 Figure 24 Total grip v. drawbar pull 49 Figure 25 Radial deflection v. total, grip 50 Figure 26 Forces applied to chuck 52 Figure 27 Loading on chuck (2nd operation) (turning and facing) 53 Figure 28 Loading on chuck and spindle (1st operation
15、) 54 Table 1 Typical value of density, p 2 Table 2 Specific cutting forces, k s , for turning, facing and boring 3 Table 3 Work material factor, k, for drilling (and deep hole boring) torque 5 Table 4 Work material factor, k f , for drilling (and deep hole boring) feed 6 Table 5 Value of work materi
16、al factor, k, for tapping 6 Table 6 Values of tap factor, C t 7 Table 7 Values of thread depth factor, C d , for tapping 7 Table 8 Values of thread factor, C m , for tapping 8 Table 9 Experimentally determined gripping coefficient, sp(mandrel chuck) (taken from VDI3106) 15 Table 10 Maximum periphera
17、l speeds for various diameters of chuck bodies 17 Table 11 Radii of gyration and moments of inertia 19 Table 12 Typical values of inertia for chucks where jaws are outwardly offset and lie flush against the outside diameter 20 Table 13 Values of k $and k $ $ 24 Publications referred to Inside back c
18、overBS1983-5:1989 BSI 09-1999 iii Foreword This Part of BS1983 has been prepared under the direction of the Machine Engineers and Hand Tools Standards Committee and is based on a draft submitted by the Advanced Manufacturing Technology Research Institute (AMTRI). This Part of BS1983 will also be sub
19、mitted as a UK proposal to the International Organization for Standardization (ISO) for consideration as an International Standard. Lathe chucks operated at any speed are, potentially, very dangerous. They have to be suitably guarded in order to ensure that personnel do not come into contact with a
20、moving chuck and that parts released from the chuck (for whatever reason) cannot be thrown at personnel either directly or after a ricochet. Power chuck controls also have to be suitably interlocked such that workpieces are not inadvertently released. These safety aspects are covered in BS1983-4 “Sp
21、ecification of criteria to be stated affecting performance of power operated workholding chucks at speed” and in BS5304 “Code of practice for safeguarding of machinery”. However, because of the versatility of lathe chucks it follows that chuck designers and manufacturers cannot know the full range o
22、f uses to which their chucks will be put (i.e.range of machines on which a chuck may be mounted, type of jaws to be fitted, type of workpiece to be held). It is essential, therefore, for the user to take some responsibility for the application of a chuck. Further, in order that such duties can reaso
23、nably be undertaken by the user, it is essential that sufficient design data are available and that methods of calculation and/or of testing are specified. The machine tool manufacturer will also be involved in certain aspects of these problems. This Part of BS1983 attempts to outline the duties of,
24、 and to provide some of the necessary information needed by: a) the machine tool manufacturer; b) the chuck manufacturer; c) the chuck user. However, because of the large number of chucks already in use it is necessary also to attempt to recommend the proper course of action regarding the applicatio
25、n of existing chucks for which the required design data were not, in fact, passed over from manufacturer to user and which are now unobtainable. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct app
26、lication. 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, pages i to iv, pages1to 58, an inside back cover and a back cover. This standard has been updated (see copyright date
27、) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS1983-5:1989 BSI 09-1999 1 1 Scope This Part of BS1983 identifies and describes safe practices for design operation of workholding chucks used on turning machines. The technic
28、al aspects covered by this code concern: a) the adequacy of the gripping force in the chuck; b) the fact that at excessive speed there may be failure of chuck components (fracture or excessive yielding); c) acceptable degrees of lack of balance and consequent vibration; d) the inertia loading impose
29、d on the machine drive both by the chuck and by the workpiece; e) gravitational forces arising from the mass of the chuck and workpiece, together in some circumstances with cutting forces, and their effect on the machine; f) other aspects concerning the safe operation of lathe chucks. Whilst primari
30、ly intended for application to lever and wedge type power chucks, including centrifugally compensated types, this code of practice can and should also be applied to manual chucks, but in such cases it is necessary to know the input torque. NOTE 1It should be recognized that even when a torque wrench
31、 or power driver is used, the grip is known to a lesser accuracy than, say, that of a power chuck having an hydraulically operated drawbar. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Chuck grip 2.1 General It should be recognized that the
32、re will be change of grip as the rotational speed increases even when the chuck has centrifugal compensation. In the case of uncompensated, or only partially compensated, chucks set up for external grip, i.e.the jaws move inwards radially as the chuck is tightened, then an increase in rotational spe
33、ed causes a loss of grip. However, when set up for internal grip an increase in rotational speed causes an increase in grip. Over-compensation has the opposite effect, i.e.an external grip increases with speed. However over-compensation is not recommended in general because it may lead to progressiv
34、e tightening if the speed is cycled up and down repeatedly. It is essential that the chuck gripping condition is evaluated by the user or by tooling experts employed by him. 2.2 Forces applied to the chuck 2.2.1 General. The forces and torques applied via the workpiece to the jaws of the chuck can b
35、e represented by four terms: Each cutting tool, deadweight force and out-of-balance force and torque makes a contribution, usually to two or more of these total forces and torques, hence each contribution has to be calculated or measured. Evaluation of mass induced forces requires values of density
36、(seeTable 1) unless components can be weighed. Evaluation of dynamic forces involves also the eccentricity, e (see clause4). C F ax the total axial thrust; C F r the total radial force; C M d the total torque (about the spindle axis); C M k the total (tilting) moment (about an axis perpendicular to
37、the spindle in the transverse centre plane of the jaws).BS1983-5:1989 2 BSI 09-1999 Table 1 Typical value of density, 2.2.2 Cutting forces and torques. There are many elaborate methods of calculating cutting forces and these methods are not precluded. Nevertheless the following simple methods are de
38、emed to be sufficiently accurate. a) For turning, facing and boring: 1) Estimate the tangential cutting force, F s(in N), as: F s= depth of cut (in mm) feed (in mm) specific cutting force (in N/mm 2 ) where the specific cutting force is taken fromTable 2. kg/m 3 Magnesium alloy Aluminium alloy Iron
39、Steel Zinc Tin Copper Nickel Brass 1800 2750 7500 7850 7000 7290 8780 8800 8280 (on average)BS1983-5:1989 BSI 09-1999 3 Table 2 Specific cutting forces, k s , for turning, facing and boring Material Tensile strength Brinell hardness number a Specific cutting force, k s Feed per revolution 0.1mm 0.2m
40、m 0.4mm 0.8mm N/mm 2 HB N/mm 2 N/mm 2 N/mm 2 N/mm 2 Carbon steels low carbon (0.15%C) low carbon (0.25%C) medium carbon (0.4%C) high carbon (0.55%C) up to 490 490 to 580 580 to 680 680 to 830 up to 150 150 to 200 180 to 250 200 to 300 3600 4000 4200 4400 2600 2900 3000 3150 1900 2100 2200 2300 1360
41、1520 1560 1640 Cast steel 290 to 490 490 to 680 680 + 3200 3600 3900 2300 2600 2850 1700 1900 2050 1240 1360 1500 Alloy steels 680 to 830 830 to 970 970 to 1370 1390 to 1750 4700 5000 5300 5700 3400 3600 3800 4100 2450 2600 2750 3000 1760 1850 2000 2150 Stainless steel 580 to 680 5200 3750 2700 1920
42、 Tool steel 1460 to 1750 5700 4100 3000 2150 Manganese hardened steel 6600 4800 3500 2520 Cast iron up to 200 1900 1360 1000 720 Cast iron 200 to 250 2900 2080 1500 1080 Cast iron, alloy 250 to 400 3200 2300 1700 1200 Tempered cast iron 2400 1750 1250 920 Copper 2100 1520 1100 800 Copper with commut
43、ator mica (collectors) 1900 1360 1000 720 Brass 80 to 120 1600 1150 850 600 Cast copper 1400 1000 700 520 Cast bronze 3400 2450 1800 1280 Zinc alloy Zn-Al 10-Cu2 940 700 560 430 Pure aluminium 1050 760 550 400 Aluminium alloy with high Si content (11% to 13%, Si) 1400 1000 700 520 Piston alloy Al, S
44、i (toughened) G Al-Si 1400 1250 1000 900 700 650 520 480 Other aluminium castings up to 290 290 to 420 1150 1400 840 1000 600 700 430 520 Wrought aluminium alloys 420 to 579 1700 1220 850 640 Magnesium alloys 580 420 300 220 Hard rubber, ebonite 480 350 250 180 Rubber free insulating compound Novote
45、x, Bakelite, Pertinaz 480 350 250 180 Hard paper, cardboard 380 280 200 140 Hard graphite (nuclear) 90 a See BS 860.BS1983-5:1989 4 BSI 09-1999 NOTEWhen surfacing on a lathe, the depth of cut is measured radially and the feed axially but when facing the depth of cut is measured axially and the feed
46、radially. Alternatively estimate the power, P (in W), available as inAppendix A and derive the cutting force as follows: 2) Increase F sby1% for each degree of top rake less than10, add10% to allow for tool wear. 3) Usually, feed force 0.6F s . (For difficult materials at slow speed, e.g.titanium, f
47、eed force = F s .) The feed force lies parallel to the spindle axis when cylindrical turning or boring, i.e.F vinFigure 1 toFigure 3. It lies perpendicular to the spindle axis when facing, i.e.F pinFigure 1 toFigure 3. 4) Separating force 0.25F sand may usually be neglected. The separating force lie
48、s perpendicular to the spindle axis when cylindrical turning or boring, i.e.F pinFigure 1 toFigure 3. It lies parallel to the spindle axis when facing, i.e.F vinFigure 1 toFigure 3. b) For drilling (and, approximately, for deep-hole boring): 1) Estimate the drilling torque, M (in Nm), as: M = 1.2k C
49、 s where: 2) Estimate the feed force, F a(in N), as: F = k f F s1 where: NOTE 1The information given inTable 4 andFigure 5 andFigure 6 is based on two separate series of tests and does, therefore, show small discrepancies in the region of12mm to16mm drill diameter. NOTE 2This calculation may be omitted if the workpiece is axially located by the chuck. Cutting speed, V (in m/s) = ; cutting diameter (in m) spindle speed (in r/s) Tangential cutting force, F s=
