1、BRITISH STANDARD BS ISO 10791-5:1998 Test conditions for machining centres Part 5: Accuracy and repeatability of positioning of work-holding pallets ICS 25.040.10BS ISO10791-5:1998 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under th
2、e authority of the Standards Board and comes into effect on 15 May 1998 BSI 05-1999 ISBN 0 580 29790 X Amendments issued since publication Amd. No. Date CommentsBSISO10791-5:1998 BSI 05-1999 i Contents Page National foreword ii Foreword iii Text of ISO 10791-5 1BS ISO10791-5:1998 ii BSI 05-1999 Nati
3、onal foreword This British Standard reproduces verbatim ISO10791-5:1998 and implements it as the UK national standard. It partially replaces BS4656-30:1992 which will be withdrawn once all other parts of this standard are published. The UK participation in its preparation was entrusted to Technical
4、Committee MTE/1, Machine tools, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and Europ
5、ean developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. BS4656-30:1992 covered the subject of Test conditions for machining centres in one Standard. ISO10791 deals with the same subject but in a number of diff
6、erent parts. This part of ISO10791 partially supersedes BS4656-30:1992 in the following way: Section4 of this standard replaces Test D19 of BS4656-30:1992. The main differences are that D19 requires the use of a master pallet whilst this standard specifies checks on individual pallets associated wit
7、h the machine. Test D19 of BS4656-30:1992 also uses the maximum range from 3 repeat cycles whilst this standard specifies using the maximum range from 5 cycles. Also, test D19 of BS4656-30:1992 had a permissible deviation of 0.010 mm at 300 mm radius whilst this standard uses a range of deviation de
8、pending on the length of the shortest side of the pallet (e.g. L 500 mm Repeat = 0.008 mm). Section 5 of this standard replaces Test D20 of BS4656-30:1992. The main difference is that test D20 addresses repeatability of positioning whilst Section5 of this standard addresses positioning accuracy. Cro
9、ss-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electron
10、ic Catalogue. 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 Standard does not of itself confer immunity from legal obligations. Summary of pages This docum
11、ent comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 6 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 theinside front cover.
12、BS ISO10791-5:1998 ii BSI 05-1999 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative references 1 3 Preliminary remarks 1 3.1 Measuring units 1 3.2 Reference to ISO 230-1 and ISO 230-2 1 3.3 Axes coding 2 3.4 Tests to be performed 2 3.5 Measuring instruments 2 4 Repeatability of positio
13、ning of individual pallets on the machine 2 4.1 Location of instruments 2 4.2 Measurement procedure 2 4.3 Formulae for calculating the deviations from individual readings 3 4.4 Tolerances 3 4.5 Checking and measuring instruments 4 4.6 Reference to ISO 230-2 4 4.7 Measured deviations 4 5 Positioning
14、accuracy of a batch of pallets relative to a pallet receiver 4 5.1 Location of instruments 4 5.2 Formulae for calculating the deviations from individual readings 5 5.3 Tolerances 5 5.4 Checking and measuring instruments 5 5.5 Reference to ISO 230-2 5 5.6 Measured deviations 5 Annex A (informative) B
15、ibliography 6 Figure 1 3 Table 1 Repeatability of positioning of individual pallets 4 Table 2 Accuracy of positioning of a batch of pallets 5 Descriptors: Machining centre, numerical control, machine tools, pallets, positioning, tests, geometric tests, determination, accuracy, testing conditions.BSI
16、SO10791-5:1998 BSI 05-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body intere
17、sted in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
18、Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75% of the member bodies casting a vote. Inter
19、national Standard ISO10791-5 was prepared by Technical Committee ISO/TC39, Machine tools, Subcommittee SC2, Test conditions for metal cutting machine tools. ISO10791 consists of the following parts, under the general title Test conditions for machining centres: Part 1: Geometric tests for machines w
20、ith horizontal spindle and with accessory heads (horizontal Z axis); Part 2: Geometric tests for machines with vertical spindle or universal heads with vertical primary rotary axis (vertical Z axis); Part 3: Geometric tests for machines with integral universal heads with horizontal primary rotary ax
21、is (vertical Z axis); Part 4: Accuracy and repeatability of positioning of linear and rotary axes; Part 5: Accuracy and repeatability of positioning of work-holding pallets; Part 6: Accuracy of feeds, speeds and interpolations; Part 7: Accuracy of a finished test piece; Part 8: Evaluation of contour
22、ing performance in the three coordinate planes; Part 9: Evaluation of the operating times of tool change and pallet change; Part 10: Evaluation of the thermal distortions; Part 11: Evaluation of the noise emission; Part 12: Evaluation of the vibration severity. Annex A of this part of ISO10791 is fo
23、r information only.iv blankBSISO10791-5:1998 BSI 05-1999 1 Introduction A machining centre, is a numerically controlled machine tool capable of performing multiple machining operations, including milling, boring, drilling and tapping, as well as automatic tool changing from a magazine or similar sto
24、rage unit in accordance with a machining programme. The object of ISO10791 is to supply information as wide and comprehensive as possible on tests which can be carried out for comparison, acceptance, maintenance or any other purpose. ISO10791 specifies, with reference to the relevant parts of ISO 23
25、0, Test code for machine tools, several families of tests for machining centres with horizontal or vertical spindle or with universal heads of different types, standing alone or integrated in flexible manufacturing systems. ISO10791 also establishes the tolerances or maximum acceptable values for th
26、e test results corresponding to general purpose and normal accuracy machining centres. ISO10791 is also applicable, totally or partially, to numerically controlled milling and boring machines, when their configuration, components and movements are compatible with the tests described herein. 1 Scope
27、This part of ISO10791 specifies, with reference to ISO230-1 and ISO230-2, the tests intended to assess the repeatability of positioning of individual pallets and the total accuracy of positioning of a batch of pallets associated with a specific machine. In a manufacturing system the accuracy of posi
28、tioning of a workpiece or a work-holding fixture depends on the fitting between pallets and receivers. It should be noted that this part of ISO10791 applies to a single machining centre, i.e.to the single receiver, with multiple pallets. The results of the tests considered here could be extended to
29、the whole manufacturing system only if the measuring instruments were placed on the different machines exactly in the same position with respect to the origins of the linear axes. This, in practice, is difficult and inaccurate, because origins of the linear axis are affected by the repeatability of
30、the axes. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO10791. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on
31、this part of ISO10791 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 230-1:1996, Test code for machine tools Part1: Geometric accuracy of ma
32、chines operating under no-load or finishing conditions. ISO 230-2:1997, Test code for machine tools Part2: Determination of accuracy and repeatability of positioning of numerically controlled axes. ISO 8526-1:1990, Modular units for machine tools Workholding pallets Part 1: Workholding pallets up to
33、 800mm nominal size. ISO 8526-2:1990, Modular units for machine tools Workholding pallets Part 2: Workholding pallets of nominal size greater than 800 mm. 3 Preliminary remarks 3.1 Measuring units In this part of ISO10791, all linear dimensions, deviations and corresponding tolerances are expressed
34、in millimeters; angular dimensions are expressed in degrees, and angular deviations and the corresponding tolerances are expressed in ratios but in some cases microradians or arcseconds may be used for clarification purposes. The equivalence of the following expressions should always be kept in mind
35、: 0,010/1 000 = 10 10 6= 10 4rad . 2 3.2 Reference to ISO 230-1 and ISO 230-2 To apply this part of ISO10791, reference shall be made to ISO230-1 as far as geometric measurements and the recommended accuracy of testing equipment are concerned. ISO230-2 shall be referred to for the methods of determi
36、ning repeatability and accuracy of positioning.BS ISO10791-5:1998 2 BSI 05-1999 3.3 Axes coding In this part of ISO10791, some letters have been used with a general meaning, which has to be clarified for each case. These letters and relevant meanings are indicated hereunder: M and N correspond to th
37、e horizontal axes of the machine and shall be replaced by X and Z (or Z and X) for horizontal machining centres and X and Y (or Y and X) for vertical machining centres, in function of the approaching direction of the pallet; P corresponds to the vertical axis and shall be replaced by Y for horizonta
38、l machining centres and by Z for vertical machining centres; R corresponds to the rotary axis of the pallet and shall be replaced by B for horizontal machining centres and by C for vertical machining centres; i is the progressive number related to the pallet (the i-th pallet); j is the progressive n
39、umber related to the approach (the j-th approach); k is used in the formulae for indicating the individual axes M, N, P and R. 3.4 Tests to be performed When testing a machine, it is not always necessary or possible to carry out all the tests described in this part of ISO10791. When the tests are re
40、quired for acceptance purposes, it is up to the user to choose, in agreement with the supplier/manufacturer, those tests relating to the components and/or the properties of the machine which are of interest. These tests, as well as the batch size to be used as a sample for the accuracy test, are to
41、be clearly stated when ordering a machine. Mere reference to this part of ISO10791 for the acceptance tests, without specifying the tests to be carried out, and without agreement on the relevant expenses, cannot be considered as binding for any contracting party. 3.5 Measuring instruments The measur
42、ing instruments indicated in the tests described in the following sections are examples only. Other instruments measuring the same quantities and having at least the same accuracy may be used. Dial gauges shall have a resolution of0,001 millimeters. 4 Repeatability of positioning of individual palle
43、ts on the machine 4.1 Location of instruments In Figure 1, a measurement setup is shown which makes use of a square placed on the pallet, lying against gauge blocks set against the reference slots. If the pallet references for locating the workpiece or the work holding fixture are different (e.g., l
44、ocation holes or edge locators as shown in ISO8526-1 and ISO8526-2), it is important that the checking instruments be located on each pallet exactly in the same position compared with the references. Measurement instruments 1, 2 and 4 should be located as close as possible to the centre lines of the
45、 pallet. 4.2 Measurement procedure Whenever possible, the axes shall be locked. A special fixture, or a square, or any other suitable artifact shall be located on the pallet. The locating references for the work holding fixture shall be used to ensure the placement of the artifacts exactly in the sa
46、me position and orientation on each pallet. The dial gauges shall be fixed in such positions as to allow for the movements for the pallet loading and unloading without interference. To prevent interference between the styli and the artifacts, the readings shall be taken by means of gauge blocks alwa
47、ys placed between the artifact and the stylus of the dial gauge. The dial gauges shall be zeroed only at the first positioning approach of the first pallet. Each pallet shall be loaded and unloaded five times without resetting the dial gauges. The five readings of each dial gauge shall be recorded.
48、The general deviation a in the various directions shall be determined from the individual readings as indicated in 4.3. NOTEThe a Rdeviation might also be measured by means of an autocollimator provided that the mirror is placed on the different pallets exactly with the same orientation with respect
49、 to the locating references for the work holding fixture.BSISO10791-5:1998 BSI 05-1999 3 4.3 Formulae for calculating the deviations from individual readings Representing the dial gauge reading in general as a, and the repeatability of positioning of the pallet along (or around) each axis as W, the required quantities are determined from the individual readings in the following way: where 4.4 Tolerances where L is the shorter side of the pallet. M and N are horizontal axes P is the vertical axis R is the rotary axis
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