1、Designation: F 2754/F 2754M 09Standard Test Method forMeasurement of Camber, Cast, Helix and Direction of Helixof Coiled Wire1This standard is issued under the fixed designation F 2754/F 2754M; the number immediately following the designation indicates theyear of original adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the various standard methodsthat are used for measuring camber, cast, h
3、elix, and helixdirection. The wire may be coiled with or without a spool.1.2 This test method applies to round wire that has adiameter between 0.0127 to 4.78 mm (0.0005 to 0.188 in.). Italso applies to flat or shaped wire.1.3 This test method does not apply to superelastic nitinolwire. It does apply
4、 to the as-drawn condition of nitinol wire.1.4 This test method does not apply to the measurement ofthe straightness of straightened to length wire and tubing.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may no
5、t be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibilit
6、y of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Fig. 1(a) through Fig. 1(e) illustrate the physical mean-ing of cast, helix, direction of helix, and camber.2.2 Definitions:2
7、.2.1 castthe maximum diameter of coiled wire when onecomplete circumference rests completely on a flat surface suchas a table, workbench, or floor. Fig. 1(a).2.2.2 helixthere are two common methods for measuringhelixfree end lift and hanging helix. These definitions aredefined by Fig. 1(b) and Fig.
8、1(c), respectively.2.2.2.1 helix (free end lift)the maximum lift of the freeend of the wire when laid on a flat surface, Fig. 1(b).2.2.2.2 helix (hanging helix)the maximum distance be-tween two adjacent coils of wire, Fig. 1(c).Ahanging helix canalso be measured by suspending the coils.2.2.3 helix d
9、irectioncan be left or right-handed depend-ing upon how the wire was coiled, Fig. 1(d)2.2.3.1 left-handed helixthe wire is coiled in a counter-clockwise direction, Fig. 2(a).2.2.3.2 right-handed helixthe wire is coiled in a clock-wise direction, Fig. 2(b).2.2.4 camberthe deflection in the width dire
10、ction of a flator shaped wire, Fig. 1(e).3. Summary of Test Method3.1 The maximum diameter of at least one complete cir-cumference is measured using a linear scale while it is restingcompletely flat on a flat surface such as a table, workbench, orfloor (cast measurement). The maximum lift of the fre
11、e end ofthe wire when laid on a flat surface is the free end lift helix andis measured using a linear scale. A hanging helix can bemeasured using a linear scale while the wire is being suspended(hanging helix free end lift). Camber is the offset in the widthdimension of a flat or shaped wire and can
12、 also be measuredusing a linear scale while the wire is resting on a flat surface.Alternatively, a coordinate measurement machine or opticalcomparator may be used. Helix direction is the direction whichthe wire has been coiled.4. Significance and Use4.1 The process of coiling wire causes the wire to
13、 take on acurvature from the process of being mechanically deformedinto a coiled geometry. The curvature in the wire is permanentunless the wire is straightened. It will affect how the coiledwire will react when it is subjected to additional wire formingoperations. In addition, residual stresses ind
14、uced from thecoiling operation can cause elastic recoil or spring back insubsequent wire forming operations unless the material isstraightened and stress relieved prior to forming. These re-sidual stresses can create wide variations in the dimensions ofcomponents and or parts that have been built us
15、ing the coiledwire (cast).1This test method is under the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Feb. 1, 2009. Published February 2009.1Copyright ASTM Inte
16、rnational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 The direction that the wire has been coiled affects howthe wire will be taken off of the coil for subsequent wireforming operations (helix direction).4.3 Lift or spacing between adjacent coils also aff
17、ects howthe wire will be taken off of the coil and can also affect thedimensions of components and or parts that have been builtusing the coiled wire due to residual stresses (helix).5. Apparatus5.1 A linear scale is required for measurement of the cast ofcoiled wire. An alternate approach is to use
18、 a profilometer orcoordinate measurement machine.5.2 A template is useful for measuring the cast of coiledwire that is greater than 0.6 m (24 in), Fig. 3. An alternativeapproach is to use a coordinate measurement machine oroptical comparato5.3 Special equipment is not required for measurement ofcamb
19、er, helix, or the direction of helix.6. Test Specimen6.1 Test Specimen for Measuring Cast:6.1.1 It is preferred to fixture the spool or coil in a suitablemanner so it does not move as the wire is removed. It isimportant to keep a firm tension on the wire to prevent tanglingwhich could alter the meas
20、urement.6.1.2 Scrap the first 1.5 to3m(5to10ft)ofwire in orderto eliminate any possible end effects and wire damage frombeing tied off. Ensure that the wire is easily coming off of thespool or coil without any crossing over of the wire.6.1.3 Allow the uncoiled wire to naturally form at least onecomp
21、lete circle that rests completely flat on a level surfacesuch as a smooth table, bench, or the floor.NOTE(a) Definition of cast. (b) Definition of helix as measured by lift method. (c) Definition of helix as measured by hanging method. (d) Definitionof helix direction. (e) Definition of camber.FIG.
22、1 Standard Definitions for Cast, Helix, and Camber of Spooled WireNOTE(a) Definition of left-handed helix direction. (b) Definition of right-handed helix direction.FIG. 2 Standard Definition for Direction of HelixF 2754/F 2754M 0926.1.4 For wire with a cast1morgreater (or 36 in. orgreater), cut a se
23、ction of wire 0.5 m (18 in.) in length from thespool.6.2 Test Specimen for Determining the Direction of HelixCut enough wire from the spool or coil for approximately 2 to4 full diameters of the natural cast of wire. It is important tokeep tension on the wire as it is unspooled in order to preventtan
24、gling which could effect the measurement.6.3 Test Specimen for Measurement of Helix:6.3.1 Free Lift MethodRemove approximately 2 to 4 fulldiameters of the natural cast of the wire and allow them to reston a flat surface. It is important to keep tension on the wire asit is unspooled in order to preve
25、nt tangling which could effectthe measurement.6.3.2 Hanging MethodRemove approximately 2 to 4 fulldiameters of the natural cast of the wire and suspend themusing your index finger. It is important to keep tension on thewire as it is unspooled in order to prevent tangling which couldeffect the measur
26、ement.6.4 Test Specimen for Measurement of Camber in Flat orShaped WireA cut length, typically 30 cm (12.0 in.), or asagreed upon between the purchaser and supplier, should beremoved from the spool or coil.7. Procedure7.1 Measurement of Cast:7.1.1 Allow the test specimen to form at least one complet
27、ecircle that rests completely flat on a level surface such as asmooth table, bench, or the floor.7.1.1.1 For wire with a cast less than 2.5 cm (1 in.), measurethe cast at the largest diameter of the circle using a linear scale,profilometer, or coordinate measurement machine. The castshould be rounde
28、d to the closest 5 mm (0.25 in.) measurement.For wire with a cast between 2.5 cm (1 in.) and less than 1 m(36 in.), measure the cast at the largest diameter of the circleusing a linear scale, optical comparator, or coordinate measure-ment machine. The cast should be rounded to the closest 2.5cm (1 i
29、n.) measurement or as is specified on the purchase order.If the cast is greater than 1 m (36 in.), use a sectioned piece ofwire as is described in 6.1.4. The sectioned piece of wireshould be slid on the template until the curvature matches asclosely an arc on the template. This is the cast measureme
30、ntand should be measured in 0.25 m (10 in.) increments or as isspecified on the production order. An alternate approach is touse a optical comparator or coordinate measurement machine.7.2 Determination of the Direction of Helix:7.2.1 Suspend the wire specimen described in 6.2 by grasp-ing it between
31、 a couple of fingers or by suspending it on astraight object such as an ink pen and observe the direction thatit spirals away from you.7.2.1.1 A right hand helix spirals away from you in aclockwise direction, Fig. 2(a). A left hand helix spirals awayfrom you in a counterclockwise direction, Fig. 2(b
32、).7.3 Measurement of Helix of Coiled Wire:7.3.1 Measurement of Helix by Free End Lift MethodUsing the wire specimen described in 6.3.1 if the free end doesnot lift from the top of the flat surface, the wire has a zero liftby the free end lift method. If a lift is observed, use a linearscale to measu
33、re the amount of maximum spacing between thefree end and adjacent coil. If the free end lift is between 0 to 25mm (0 to 1 in.), the helix shall be reported to the nearest 10 mm(0.25 in.). If the free end lift is greater than 25 mm (1 in.), thehelix shall be reported to the nearest 15 mm (0.5 in.). T
34、hisprocedure is to be used to measure and report the free end liftunless agreed upon otherwise between the purchaser andsupplier. An optical comparator or coordinate measurementmachine can be used alternatively to measure helix.7.3.2 Measurement of Helix by Suspension (Hanging)Method:7.3.2.1 Using t
35、he test specimen described in 6.3.2, thesuspended or hanging helix is measured using a linear scale atthe point of maximum separation at the bottom of the loop.One complete diameter of wire should be removed from thespool and suspended on a straight shaft. Hanging helix shouldbe reported in 1 cm (0.
36、5 in.) increments unless agreed uponotherwise between the purchaser and the supplier.FIG. 3 Example of a Template Used for Measuring Large Diameter Spooled Wire CastF 2754/F 2754M 0937.3.2.2 Use of background lighting or a distinct in colorbackground will enhance the visibility of the helix whensmal
37、ler diameter wire is being measured.7.4 Measurement of Camber in Flat or Shaped WireUsingthe wire specimen described in 6.4, the amount of cambershould be measured using a linear scale. Place the cut length ofwire on a flat surface with the two cut ends of the wire againsta straight edge. The camber
38、 value is the distance between thestraight edge and inside radius of the wire. See Fig. 1(e).Report the amount of camber present to the closest 3 mm(0.125 in.) unless otherwise agreed upon by the purchaser andthe supplier.8. Report8.1 The report shall include the following informationunless otherwis
39、e specified:8.1.1 Material and sample identification.8.1.2 Cast reported in SI or inch-pounds units as requestedby the purchaser.8.1.3 Helix in SI or inch-pounds units as requested by thepurchaser.8.1.4 Direction of the helix if it has been requested by thepurchaser.8.1.5 Camber reported in SI or in
40、ch-pounds units as re-quested by the purchaser for flat or shaped wire.9. Keywords9.1 camber; coil; helix; helix directionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expre
41、ssly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised
42、, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may a
43、ttend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 2754/F 2754M 094
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