1、BRITISH STANDARD BS4656-36: 1987 ISO8636-1: 1987 Accuracy of machine tools and methods of test Part36: Specification for plano-milling machines, portal type ISO title: Acceptance conditions for plano-milling machines Testing of the accuracy Part1: Portal-type machines UDC 621.9.01187.001.4:621.914.2
2、1BS4656-36:1987 This British Standard, having been prepared under the directionof the Machine, Engineers and Hand Tools Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 23December1987 BSI 10-1999 The following BSI references relate to the work on this
3、 standard: Committee reference MTE/1 Draft for comment85/73679 DC ISBN 0 580 16290 7 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 t
4、he following bodies were represented: Advanced Manufacturing Technology Research Institute Cranfield Institute of Technology Department of Trade and Industry Mechanical Engineering and Manufacturing Technology Division (Mmt) Health and Safety Executive Institution of Production Engineers Ministry of
5、 Defence University of Aston in Birmingham Amendments issued since publication Amd. No. Date of issue CommentsBS4656-36:1987 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Preliminary observations 1 4 Defi
6、nitions and description 1 5 Nomenclature and designation of axes 3 6 Test conditions and permissible deviations 6 Annex Equivalent terms 34 Figure 1 Portal-type plano-milling machine with variable height cross-rail 3 Figure 2 Type1: machine with two milling heads 4 Figure 3 Type2: machine with three
7、 milling heads 4 Figure 4 Type3: machine with one milling head on the cross-rail 5 Figure 5 Type4: machine with one milling head on the cross-rail and an additional milling head swivelling on axes C and A 5 Publication referred to Inside back coverBS4656-36:1987 ii BSI 10-1999 National foreword This
8、 Part of BS4656 has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Committee and implements agreements of the International Organization for Standardization (ISO). It is identical with ISO8636:1987 “Acceptance conditions for plano-milling machines Testing of the
9、 accuracy Part1: Portal-type machines”. Inch dimensions. In accordance with the UK policy of metrication, inch dimensions given in this standard are not valid and are included for information purposes only. Abbreviations. For the purposes of this standard, various methods of expressing permissible d
10、eviations are employed, each having a particular type of application. The methods employed are as follows. Diagrams. For reasons of simplicity the diagrams in this standard illustrate only one type of machine. Terminology and conventions. The text of the International Standard has been approved as s
11、uitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice t
12、o use a full point on the baseline as the decimal marker. Wherever the words “this part of ISO8636” appear, referring to this standard, they should be read as “this Part of BS4656”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards
13、are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. - - -/- - - This type of expression applies to deviations of perpendicularity that are ratios. - - - for any length of - - - This type of expression applies to
14、 deviations of straightness and parallelism, and is used in fact for local permissible deviations, the measurement length being obligatory. - - - per - - - This type of expression applies to deviations of straightness and parallelism and is used to recommend a measurement length, but in this case th
15、e proportionality rule comes into operation if the measurement length differs from that indicated. Cross-reference International Standard Corresponding British Standard ISO230:1961 BS3800:1964 Methods for testing the accuracy of machine tools (Technically equivalent) Summary of pages This document c
16、omprises a front cover, an inside front cover, pagesi andii, pages1 to34, 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.BS4656-36:1987 BSI 10
17、-1999 1 1 Scope and field of application This part of ISO8636 specifies, with reference to ISO230-1, preliminary tests, geometrical tests and practical tests for portal-type plano-milling machines which apply to general purpose, normal accuracy, machines and gives the corresponding permissible devia
18、tions. This part of ISO8636 is applicable to machines with moving tables and fixed double columns. It does not include single-column (open-sided) machines and those with fixed tables and moving columns. This part of ISO8636 deals only with checking the machine accuracy. It does not apply to the test
19、ing of the running of the machine (vibration, abnormal noise, stick-slip motion of components, etc.) nor to the machine characteristics (speeds, feeds etc.) which should generally be checked before testing the accuracy. This part of ISO8636 provides the nomenclature used for the principal parts of t
20、he machine and the designation of the axes. NOTEIn addition to terms used in the three official ISO languages (English, French and Russian), this part of ISO8636 gives the equivalent terms in the German and Italian languages in an annex; these have been included at the request of ISO Technical Commi
21、ttee ISO/TC39 and are published under the responsibility of the member bodies for Germany, F.R. (DIN) and Italy (UNI). However, only terms given in the official languages can be considered as ISO terms. 2 Reference ISO230-1, Acceptance code for machine tools Part1: Geometric accuracy of machines ope
22、rating under no-load or finishing conditions. 3 Preliminary observations 3.1 In this part of ISO8636, all dimensions and deviations are expressed in millimetres and in inches. 3.2 To apply this part of ISO8636, reference should be made to ISO230-1, especially for the installation of the machine befo
23、re testing, warming up of spindle and other moving parts, description of measuring methods and recommended accuracy of testing equipment. 3.3 The temperature conditions throughout the tests shall be specified by agreement between manufacturer and user. 3.4 The sequence in which geometrical tests are
24、 given is related to the sub-assemblies of the machine and in no way defines the practical order of testing. In particular, to make instrument mounting or gauging easier, tests may be applied in any order. 3.5 When inspecting a machine, it is not always necessary to carry out all the tests given in
25、this part of ISO8636. It is up to the user to choose, in agreement with the manufacturer, those tests relative to the properties which are of interest to him, but these tests are to be clearly stated when ordering a machine. 3.6 Practical tests shall be carried out with finishing cuts and not with r
26、oughing cuts which are liable to generate appreciable cutting forces. 3.7 When establishing the tolerance for a measuring range different from that given in this part of ISO8636 (see sub-clause2.311 of ISO230-1), it should be taken into consideration that the minimum value of tolerance is0,005mm(0.0
27、002in). 3.8 For reasons of simplicity, the diagrams in this part of ISO8636 are based on a single machine type. 4 Definitions and description 4.1 Definitions of the machining processes that can be carried out 4.1.1 milling operations milling is a machining operation which consists of removing materi
28、al by means of a rotary tool called a “milling cutter” of which there are several different types. The usual operations of milling mostly involve face milling or end milling. The tools are mounted either in the spindle taper or on the spindle front face 4.1.2 boring operations boring consists of mac
29、hining the diameters of cylindrical, conical, blind or through holes, to the required sizeBS4656-36:1987 2 BSI 10-1999 4.1.3 drilling and tapping operations these operations consist of drilling and/or tapping blind or through holes 4.2 Definition of plano-milling machines and main types 4.2.1 Defini
30、tion portal-type plano-milling machine: double-column machine with one or more vertical spindle heads mounted on the cross-rail, above a table which has longitudinal traverse only additional horizontal spindle heads may be mounted on the columns, of which the horizontal spindle axes may be inclinabl
31、e 4.2.2 main types of machines these machines are classified into two types depending upon construction: plano-milling machines with a movable height cross-rail and a bridge or tiepiece between the columns; plano-milling machines with a fixed height cross-rail which may replace the bridge or tiepiec
32、e. 4.3 Description See5.1, in which the numbers are explained. 4.3.1 Bed and table The bed(1) is the fixed base of the machine which may be constructed of several parts. It supports the table(3) which moves parallel to the major axis of the bed. 4.3.2 Column, cross-rail and tiepiece or bridge The co
33、lumns(4) and(5) provide the vertical frame of the machine and are fixed on either side of the bed. The columns may be fitted with vertical slideways to accommodate a side milling head(9) with a horizontal or inclinable spindle axis. The bridge or tiepiece(10) is a fixed piece connecting both columns
34、 at or near the top. The cross-rail(7) has its major axis parallel to the table plane and is fitted with horizontal slideways on which one or more milling heads(8) with vertical or inclinable spindles can move. The variable height cross-rail may be moved up and down the vertical slideways(6) on the
35、columns. In the case of machines with fixed height cross-rail, the latter is also fastened to the columns and may replace the bridge or tiepiece. 4.3.3 Milling head These heads include the spindle and driving mechanism and the ways for mounting on the cross-rail or column. In some cases the spindle
36、may be mounted in a ram or quill(12) with a feed motion for drilling or boring operations. 4.3.4 Cutting motion Cutting motion is provided by the spindles and drive mechanisms of the milling heads. 4.3.5 Feed motion The following feed movements may be provided with constant or variable feed rate: ho
37、rizontal movement of the table; horizontal or vertical movement of the cross-rail or column heads; vertical movement of spindle rams or quills (ifany); vertical movement of the cross-rail (if any). NOTEIn general, rapid traverse is available in addition to feed movement.BS4656-36:1987 BSI 10-1999 3
38、5 Nomenclature and designation of axes 5.1 Nomenclature Figure 1 Portal-type plano-milling machine with variable height cross-railBS4656-36:1987 4 BSI 10-1999 5.2 Designation of axes Figure 2 Type1: Machine with two milling heads Figure 3 Type2: Machine with three milling headsBS4656-36:1987 BSI 10-
39、1999 5 Figure 4 Type3: Machine with one milling head on the cross-rail Figure 5 Type4: Machine with one milling head on the cross-rail and an additional millinghead swivelling on axes C and ABS4656-36:1987 6 BSI 10-1999 6 Test conditions and permissible deviations 6.1 Preliminary tests No. Diagram O
40、bject G01 A Bed Verification of levelling of bed slideways a : a) Longitudinal verification: checking of accuracy of slideways in a vertical plane. b) Transverse verification: checking of position of slideways with respect to one another.BS4656-36:1987 BSI 10-1999 7 Permissible deviation Measuring i
41、nstruments Observations and references to the ISO230-1 acceptance code mm in Sub-clauses3.1 and3.2 Local tolerance: Table dismounted. a) a) Place level in the longitudinal direction on each slideway at a number of equally spaced positions along the bed length. 0,02 0.0008 over any measured length (f
42、lat or convex) of 1000 40 b) Straightedge, precision levels, special support b) Place the special support and level in the transverse direction on each slideway. It shall not indicate slope variations exceeding the tolerance at any measuring point over the bed length. 0,02/1000 0.0008/40. Such check
43、s shall be carried out when mounting the machine. a The shape characteristics of the bed basic plane from which the permissible deviation is measured shall be supplied graphically or described by the manufacturer.BS4656-36:1987 8 BSI 10-1999 No. Diagram Object G02 Checking of straightness of bed ref
44、erence slideways in a horizontal plane. G03 Checking of parallelism of bed reference slideways in a horizontal plane (formachines with two reference slideways).BS4656-36:1987 BSI 10-1999 9 Permissible deviation Measuring instruments Observations and references to the ISO230-1 acceptance code mm in 0
45、,02 for L a u2000 0,03 for200020000 0.0008 forL a u 80 0.0012 for80800 Microscope and taut wire or any other optical instrument, special support or measuring carriage Sub-clauses5.212.3 and5.222 Dismounted table. Fix taut wire to each end of slideway, stretch and orientate it. Place and orientate sp
46、ecial support and microscope on slideway. Move special support on slideway at different, equally spaced, positions and read the variation in the recorded value. In the case of machines with two V-shaped slideways, testing can be carried out by checking straightness for one slideway and parallelism f
47、or the other. Local tolerance: 0,01 0.0004 over any measured length of 500 20 a L is the slideway length. 0,02 0.0008 Special support or measuring carriage and dial gauge Sub-clause5.412.6 Place the special support on one of the reference slideways and on the opposite slideway. Move the special supp
48、ort along the slideways through various, equally spaced, positions. Read the variation in the dial gauge indication. whichever is the distance between slideways in the horizontal planeBS4656-36:1987 10 BSI 10-1999 6.2 Geometrical tests No. Diagram Object G1 B Table Checking of flatness of table surf
49、ace. G2 Checking of straightness of movement of table on bed in a horizontal plane.BS4656-36:1987 BSI 10-1999 11 Permissible deviation Measuring instruments Observations and references to the ISO230-1 acceptance code mm in x a u1000 0,02 100010000 0.0008 for L a u 80 0.0016 for 80Lu 200 0.0024 for200Lu 400 0.003 for Lu 400 Microscope and taut wire or other optical instrument Sub-clauses5.212.2, 5.212.3 and5.232.2 Fix taut wire to each end of the bed, stretch and orientate it. Fix and orientate microscope on the tabl
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