1、BRITISH STANDARD BS6808-1: 1987 Coordinate measuring machines Part1: Glossary of termsBS6808-1:1987 This British Standard, having been prepared under the directionof the General Mechanical Engineering Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 2
2、7 February1987 BSI07-1999 The following BSI references relate to the work on this standard: Committee reference GME/28 Draft for comment85/76848DC ISBN 0 580 15771 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the General Mechanical Engi
3、neering Standards Committee (GME/-) to Technical Committee GME/28 upon which the following bodies were represented: Advanced Manufacturing Technology Research Institute British Telecommunications plc Cranfield Institute of Technology Department of Trade and Industry (National Engineering Laboratory)
4、 Department of Trade and Industry (National Physical Laboratory) Gauge and Tool Makers Association Institution of Production Engineers Ministry of Defence Society of British Aerospace Companies Limited University of Manchester Institute of Science and Technology Amendments issued since publication A
5、md. No. Date of issue CommentsBS6808-1:1987 BSI 07-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 General 1 2 Types of coordinate measuring machine 2 3 Mechanical artefacts for calibration 10 4 Calibration procedures 11 5 Measurement 11 6 Geometry 12 7 Components 13 Ind
6、ex 14 Figure 1 Cantilever coordinate measuring machine 2 Figure 2 Column coordinate measuring machine 3 Figure 3 Moving horizontal arm coordinate measuring machine 4 Figure 4 Fixed horizontal arm coordinate measuring machine 5 Figure 5 Gantry coordinate measuring machine 6 Figure 6 L-shaped bridge c
7、oordinate measuring machine 7 Figure 7 Fixed bridge coordinate measuring machine 8 Figure 8 Moving bridge (portal) coordinate measuring machine 9 Publications referred to Inside back coverBS6808-1:1987 ii BSI 07-1999 Foreword This Part of BS6808 has been prepared under the direction of the General M
8、echanical Engineering Standards Committee at the request of manufacturers and users of coordinate measuring machines (CMMs). This Part of BS6808 defines the terms used in Part2 1) , whilst Part3 1)is a code of practice and gives guidance on the implementation of Part2. The terms which are defined re
9、late to CMMs themselves, but further terms are to be added which will cover the associated computer software. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British
10、 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, pages1 to14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorp
11、orated. This will be indicated in the amendment table on the inside front cover. 1) In preparation.BS6808-1:1987 BSI 07-1999 1 This Part of BS6808 defines terms relating to coordinate measuring machines. NOTEThe titles of the publications referred to in this Part of BS6808 are listed on the inside b
12、ack cover. 1 General No. Term Definition 101 coordinate measuring machine (CMM) A machine having a series of movable members, a sensing probe and a workpiece support member, which can be operated in such a way that the probe can be brought into a fixed and known relationship with points on the workp
13、iece surface, and the coordinates of these points can be displayed or otherwise determined with respect to the origin of the coordinate system. NOTEIn most cases the coordinate system is a rectangular or Cartesian one, but a polar or cylindrical system may be used. 102 computer controlled coordinate
14、 measuring machine A coordinate measuring machine that has the capability of performing a pre-programmed measurement sequence automatically under the control of a computer. 103 manually operated coordinate measuring machine A coordinate measuring machine where the measurement procedures are under di
15、rect human control and where operations are performed by hand.BS6808-1:1987 2 BSI 07-1999 2 Types of coordinate measuring machine NOTEThere are a very large number of possible machine configurations and those types listed in2.01 to2.08 are by no means exhaustive. However, the configurations describe
16、d are a sample of those in common usage. No. Term Definition 201 cantilever coordinate measuring machine A coordinate measuring machine employing three movable components moving along mutually perpendicular guideways in which the probe is attached to the first component which is carried on, and move
17、s vertically relative to, the second; the combined assembly of the first and second components moves horizontally relative to the third; the third component is supported at one end only, cantilever fashion, and moves horizontally relative to the machine base, and the workpiece is supported on the ba
18、se. NOTESee Figure 1. Figure 1 Cantilever coordinate measuring machineBS6808-1:1987 BSI 07-1999 3 No. Term Definition 202 column coordinate measuring machine A coordinate measuring machine employing two movable components in which the probe is attached to the first component which moves vertically r
19、elative to the machine base; the second component is mounted on, and moves in a horizontal plane relative to, the machine base, and the workpiece is mounted on the second component. NOTESee Figure 2. Figure 2 Column coordinate measuring machineBS6808-1:1987 4 BSI 07-1999 No. Term Definition 203 movi
20、ng horizontal arm coordinate measuring machine A coordinate measuring machine employing three movable components moving along mutually perpendicular guideways in which the probe is attached to the first component which is carried on, and moves horizontally relative to, the second component; the comb
21、ined assembly of the first and second components moves vertically relative to the third component; the third component moves horizontally relative to the machine base, and the workpiece is mounted on the machine base. NOTESee Figure 3. Figure 3 Moving horizontal arm coordinate measuring machineBS680
22、8-1:1987 BSI 07-1999 5 No. Term Definition 204 fixed horizontal arm coordinate measuring machine A coordinate measuring machine employing three movable components moving along mutually perpendicular guideways in which the probe is attached to the first component which is supported horizontally at on
23、e end only, cantilever fashion, and is carried on, and moves vertically relative to, the second; the combined assembly of the first and second components and the third component move horizontally relative to the machine base, and the workpiece is mounted on the third component. NOTESee Figure 4. Fig
24、ure 4 Fixed horizontal arm coordinate measuring machineBS6808-1:1987 6 BSI 07-1999 No. Term Definition 205 gantry coordinate measuring machine A coordinate measuring machine employing three movable components moving along mutually perpendicular guideways in which the probe is attached to the first c
25、omponent which is carried on, and moves vertically relative to, the second; the combined assembly of the first and second components moves horizontally relative to the third; the third component moves horizontally on two guide rails raised above the machine base on either side and the workpiece is s
26、upported on the base. NOTESee Figure 5. Figure 5 Gantry coordinate measuring machineBS6808-1:1987 BSI 07-1999 7 No. Term Definition 206 L-shaped bridge coordinate measuring machine A coordinate measuring machine employing three movable components moving along mutually perpendicular guideways in whic
27、h the probe is attached to the first component which is carried on and moves vertically relative to the second; the combined assembly of the first and second components moves horizontally relative to the third; the third component moves horizontally on two guide ways, one at the base level or below,
28、 the other raised above the base, and the workpiece is supported on the base. NOTESee Figure 6. Figure 6 L-shaped bridge coordinate measuring machineBS6808-1:1987 8 BSI 07-1999 No. Term Definition 207 fixed bridge coordinate measuring machine A coordinate measuring machine employing three movable co
29、mponents moving along mutually perpendicular guideways in which the probe is attached to the first component which is carried on, and moves vertically relative to, the second; the combined assembly of the first and second components moves horizontally along a bridge structure above, and rigidly atta
30、ched at each end to, the machine base, and the workpiece is mounted on the third component. NOTESee Figure 7. Figure 7 Fixed bridge coordinate measuring machineBS6808-1:1987 BSI 07-1999 9 No. Term Definition 208 moving bridge (portal) coordinate measuring machine A coordinate measuring machine emplo
31、ying three movable components moving along mutually perpendicular guideways in which the probe is attached to the first component which is carried on, and moves vertically relative to, the second; the combined assembly of the first and second components moves horizontally relative to the third; the
32、third component is supported on two legs, which reach down to opposite sides of the machine base, and moves horizontally relative to the base, and the workpiece is supported on the base. NOTESee Figure 8. Figure 8 Moving bridge (portal) coordinate measuring machineBS6808-1:1987 10 BSI 07-1999 3 Mech
33、anical artefacts for calibration No. Term Definition 301 ball-ended bar A gauge consisting of two spheres of the same nominal diameter mounted at the ends of a connecting rigid bar. 302 ball-plate A mechanical artefact comprising a number of spheres mounted in fixed positions on the plate, usually i
34、n a single plane. 303 gauge block A mechanical artefact with an accurately known length between its two flat and parallel end faces. NOTEThe blocks are often rectangular in cross section and less than100mm in length (see BS888 or BS4311-1 for a more detailed description). 304 hole-plate A mechanical
35、 artefact that comprises a flat plate pierced with holes whose axes are normal to one of the surfaces. 305 length bar A mechanical artefact with an accurately known length between its two flat and parallel end faces. NOTELength bars are often circular in cross section and greater than100mm in length
36、 (see BS1790 and BS5317 for a more detailed description). 306 material measure A measuring instrument reproducing in a permanent fashion during its use one or more known values of a given quantity for example, a gauge block for length. 307 space frame A mechanical artefact in which the coordinates o
37、f a number of points in three-dimensional space within the work zone of a coordinate measuring machine are established by reference to points on the space frame. 308 square A mechanical artefact with accurately known squareness. NOTESee BS939 for a more detailed description. 309 step gauge (uni- and
38、 bi-directional) A gauge comprising a rigid bar with calibrated features used for determining the accuracy of distance measurements in the direction of linear motion. NOTESome gauges can only be probed from one direction, others are constructed such that probing can be performed from both directions
39、. 310 straightedge A mechanical artefact with accurately known straightness along one or more of its edges. NOTESee BS5204 for a more detailed description. 311 transfer standard A one-, two- or three-dimensional artefact used as an intermediary to compare measurement standards, material measures or
40、measuring instruments.BS6808-1:1987 BSI 07-1999 11 4 Calibration procedures 5 Measurement 401 reversal A measurement procedure in which the test surface is measured by operating the probe in one direction and then rotating the component through180 and measuring the same test surface by operating the
41、 same probe in the opposite direction. NOTEIf, for example, the straightness of a component is to be measured, the test surface is first measured in the line of the axis under consideration. The component is then rotated through180 along the measurement axis and the same test surface measured with t
42、he same probe, operating in the opposite direction. By combining the two sets of results obtained by summation and subtraction the straightness of the component and of the coordinate measuring machine can be separately determined. By extending the technique to two axes, squareness may also be measur
43、ed. 402 staging The moving of a gauge from a first position to a second position such that a series of measurements started in the first position may be continued in the second position with the results related to the first. 501 Abbe error An error in a measuring slide system, resulting from an angu
44、lar error of movement of the slide, that causes a relative displacement between the slide measuring scale and the probe operating on the measuring line and that is proportional to the Abbe offset and the angular error of the slide. 502 Abbe offset The value of the perpendicular distance between the
45、measurement system of a coordinate measuring machine, and that point on the line of measurement where the workpiece measurement takes place. 503 cosine error The measurement error in the motion direction caused by angular misalignment between a linear displacement measuring system and the gauge bein
46、g measured. 504 discrimination The quantity that characterizes the ability of a measuring instrument to react to small changes of the quantity being measured. 505 error The algebraic difference between the result of a measurement of a dimension minus the (conventional) true value of the dimension me
47、asured. 506 hysteresis The difference between the indications of a measuring instrument when the same value of the quantity measured is reached by increasing or decreasing that quantity. 507 measuring line A line in the work zone of a coordinate measuring machine along which measurements are made. 5
48、08 measuring point A point on the surface of the workpiece at which the coordinates of the coordinate measuring machine are recorded as part of the measurement. 509 random uncertainty An error that varies in an unpredictable manner in absolute value and in sign when a large number of measurements of
49、 the same value of a quantity are made under effectively identical conditions.BS6808-1:1987 12 BSI 07-1999 6 Geometry No. Term Definition 510 repeatability The closeness of the agreement between the results of successive measurements of the same measurand carried out subject to all of the following conditions: the same method of measurement; the same observer; the same measuring instrument; the same location; the same conditions of use; repetition over a short period of time. 511 systematic error An error which, in the course o
