1、DRAFT FOR DEVELOPMENT DD ENV 12448:1997 Paper Printing and business paper Determination of the coefficient of static friction ICS 35.260.20;85.080DDENV12448:1997 This Draft for Development, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under
2、the authority of the Standards Board and comes into effect on 15 February 1997 BSI 03-1999 The following BSI reference relates to the work on this Draft for Development: Committee reference PAI/24 ISBN 0 580 27105 6 Committees responsible for this Draft for Development The preparation of this Draft
3、for Development was entrusted to Technical Committee PAI/24, Business forms, upon which the following bodies were represented: British Printing Industries Federation British Telecommunications plc Local Authority Organizations Loss Prevention Council Paper Federation of Great Britain Pira Internatio
4、nal Amendments issued since publication Amd. No. Date CommentsDDENV12448:1997 BSI 03-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of ENV 12448 3 List of references Inside back coverDDENV12448:1997 ii BSI 03-1999 National foreword This Draft for
5、Development has been prepared by Technical Committee PAI/24 and is the English language version of ENV12448:1996 Paper Printing and business paper Determination of the coefficient of static friction, published as a European Prestandard by the European Committee for Standardization (CEN). ENV12448:19
6、96 was produced as a result of international discussions in which the United Kingdom took an active part. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because it is considered that
7、further experience is required in its application before it is converted into a standard. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained for reporting to the CEN committee responsible for converting the prestandard into
8、 a European Standard. A review of the prestandard will be carried out2 years after its publication. Submission of comments from users of this publication is requested. According to the replies received, the responsible BSI Committee will judge whether to support the conversion into a European Standa
9、rd. Comments should be sent in writing to the Secretary of BSI Technical Committee, PAI/24 at BSI, 389 Chiswick High Road, London W44AL, quoting the document reference (DD ENV12448:1997), the relevant clause number and proposing, where possible, an appropriate revision of the text. NOTEInternational
10、 and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick High Road, London W44AL. Cross-references Publication referred to Corresponding British Standard EN ISO 186 BS EN ISO 186:1996 Paper and board Sampling to determine average quality EN 2018
11、7 BS EN 20187:1993 Paper, board and pulps Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theENV title page, pages2to8, an inside ba
12、ck 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 theinside front cover.EUROPEAN PRESTANDARD PRNORME EUROPENNE EUROPISCHE VORNORM ENV 12448 October 1996 ICS 35.260.20; 85.080 Descr
13、iptors: Paper, printing paper, photocopying, tests, determination, friction factor English version Paper Printing and business paper Determination of the coefficient of static friction Papier Papier dimpression et de bureau Dtermination du coefficient de frottement statique Papier Druck und Bropapie
14、re Bestimmung des statischen Reibungskoeffizienten This European Prestandard (ENV) was approved by CEN on 1996-10-05 as a prospective standard for provisional application. The period of validity of this ENV is limited initially to three years. After two years the members of CEN will be requested to
15、submit their comments, particularly on the question whether the ENV can be converted into an European Standard (EN). CEN members are required to announce the existance of this ENV in the same way as for an EN and to make the ENV available promptly at national level in an appropriate form. It is perm
16、issible to keep conflicting national standards in force (in parallel to the ENV) until the final decision about the possible conversion of the ENV into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, It
17、aly, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref.
18、 No. ENV 12448:1996 EENV12448:1996 BSI 03-1999 2 Foreword This European Prestandard has been prepared by Technical Committee CEN/TC172 “Pulp, paper and board”, the secretariat of which is held by DIN. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the foll
19、owing countries are bound to announce this European Prestandard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Nor
20、mative references 3 3 Definitions 3 4 Principle 3 5 Apparatus 3 6 Conditioning 5 7 Preparation of test pieces 6 8 Procedure 6 9 Calculation 6 10 Precision 7 11 Test report 7 Figure 1 General lay out of the friction tester 4 Figure 2 Force-time curve 5ENV12448:1996 BSI 03-1999 3 Introduction This Eur
21、opean Prestandard specifies the determination of the coefficient of static friction by the horizontal plane method. The condition of a paper surface depends on the characteristic properties of the paper. Its frictional properties are largely determined by its coefficient of static friction, s , whic
22、h is measured when a sheet of paper slides over another identical sheet of paper in the horizontal plane with a perpendicular force applied between the sheets. It relates to the force required to initiate movement between the two paper surfaces. The coefficient of friction is an empirical property o
23、f a particular material under specified testing conditions. It describes the condition of the surfaces at the moment of test. This may or may not relate to the condition of the surfaces in a specific end-use situation. Nevertheless the test results are useful in determining the combined properties o
24、f the surfaces tested. The coefficient of static friction of machine made paper can be different when measured in the machine direction (MD) or in the cross direction (CD). In the machine direction there can also be a difference between the manufacturing direction (MD +) and the counter-manufacturin
25、g direction (MD ). Often there is a difference between the two sides of the paper. 1 Scope This European Prestandard specifies a test method for the determination of the coefficient of friction using the horizontal plane method. This European Prestandard is applicable to cut-size printing and busine
26、ss papers. 2 Normative references This European Prestandard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendment
27、s to or revisions of any of these publications apply to this European Prestandard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN ISO 186, Paper and board Sampling to determine average quality (ISO186:1994).
28、EN 20187, Paper, board and pulps Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples (ISO187:1990). 3 Definitions For the purposes of this Prestandard the following definitions apply: 3.1 static friction force that resists initial
29、movement of one surface sliding over another surface 3.2 coefficient of friction ratio of the static friction to the load applied normally to the surface tested 4 Principle Test pieces of the paper under test are mounted upon a sled and table friction test apparatus. A load is normally applied in a
30、direction parallel to the interface between the test pieces. The force required to initiate sliding is measured. 5 Apparatus 5.1 Friction tester Friction tester (seeFigure 1) comprises essentially of a horizontal Table (1) and a sled (5). Test pieces of the material to be tested are fixed to the und
31、erside of the sled (5) and to the top of the horizontal Table (1).ENV12448:1996 4 BSI 03-1999 The force, parallel to the plane of contact which is required to initiate movement of the sled (5) over the horizontal Table (1) is measured. The force F can be applied by using a drive mechanism (2) on eit
32、her the sled (5) or the horizontal Table (1). Designs having two drive mechanisms (2) are also permitted. The force F may then be applied to either the sled (5) or to the horizontal Table (1). It shall however be kept parallel with the plane of contract between the materials under test. The friction
33、 tester has the following parts as described in Figure 1: 5.2 Horizontal table A horizontal Table (1) with a flat top surface of imcompressible material (metal, hard wood, glass, etc.) wide enough to accomodate the sled (5) with a margin of at least 5 mm on each side. The horizontal Table (1) shall
34、be provided with means for mounting the test piece (8) firmly so that there is no slippage between the test piece (8) and the horizontal Table(1) during the test. 5.3 Sled A sled (5) shall have of total mass (900 100)g. The underside, where the test piece (8) is mounted, is flat,60mm square and made
35、 of an incompressible material. The sled (5) shall be provided with means for mounting the test piece (8) firmly so that there is no slippage between the test piece (8) and the sled (5) during the test. NOTE 1Preferably these means should be such that the test pieces (8) can be mounted without bendi
36、ng or folding it. The orientation of the sled (5) shall remain parallel to that of the horizontal Table (1) during the entire test. NOTE 2Excessive rotational motion of the sled (5) in the plane of the horizontal Table (1) before the rectilinear motion starts can cause low results. It has been shown
37、 that rotational motion within the tolerance specified has no measurable effect. 5.4 Elevator An elevator (6) for lowering and lifting the sled (5) with respect to the horizontal Table (1). When lowering the elevator, the entire area of the two surfaces shall meet simultaneously. There shall be no s
38、liding of the sled (5) as it makes contact with the horizontal Table (1), before the force F is applied. It is important for the result of the test that there is no repositioning of the sled (5) once the surfaces have met. Even the slightest motion may influence the result. The sled (5) must neither
39、 be placed on to, nor lifted from the horizontal Table (1) by hand. 1 horizontal table (5.2) 2 driving mechanism for the sled or, alternatively, the horizontal table (5.7); 3 load cell (5.7); 4 connection between the sled and the load cell (5.6); 5 sled (5.3); 6 elavator for the sled (5.4); 7 backin
40、gs of foam rubber (5.9); 8 test pieces for the sled and the horizontal table; Z elasiticity in the connection between the load cell and the sled; h distance between the horizontal table and the plane of action of the force F. Figure 1 General lay out of the friction testerENV12448:1996 BSI 03-1999 5
41、 NOTEThe purpose of the elevator (6) is to avoid the influence of the person performing the test. The test can be carried out without the elevator (6), providing that the necessary measures are taken to avoid any motion. If the test is made without the elevator (6) it shall be noted in the test repo
42、rt. 5.5 Load cell The load cell (3) shall measure the force F applied to the sled (5) or the horizontal Table (1) by the driving mechanism (2) with an accuracy of2% of the scale reading. Means to record and display a force-time curve shall be provided. The recording means shall have a response capab
43、ility adequate to accurately portray the dynamic force-time curve (seeFigure 2). 5.6 Means for connecting the load cell to the sled A variety of means may be used to communicate the force F between the sled (5) and load cell (3). The resultant force shall be aplied centrally with respect to the squa
44、re test area. The displacement h (seeFigure 1) of the resultant force above or below the plane of contact between the test pieces (8) is not critical but shall not exceed5mm. The direction of the resultant force shall be parallel to the surface of the horizontal Table (1). NOTESome instruments may e
45、mploy a variable degree of elasticity Z for the purpose of altering the time from initial application of the pulling force to the moment at which the sliding begins (see ramp time, Figure 2). In other instruments the degree of elasticity is not a variable. 5.7 Drive mechanism To impart a vibration f
46、ree incremental force to the sled (5) which will subsequently move the sled (5) in relation to the horizontal Table (1) as specified herein. As long as the driving force F is kept parallel to the plane of contact between the test pieces (8) either the sled (5) or the horizontal Table (1) may be driv
47、en. The rate of force increase shall be such that the ramp time is between1s and5s. (Hatching in Figure 2 indicates the range of acceptable ramp times.) Since the intention is to determine only the first coefficient of static friction, there is no specific requirement for relative motion between the
48、 sled and horizontal table test pieces beyond the point at which slinding begins. 5.8 Backing Backing (7) to ensure a uniform pressure distribution. At least one of the test pieces (8) shall be backed by a compressible backing made from a sheet of medium density sponge rubber with a hardness of40IRH
49、D to60IRHD (International Rubber Hardness Degrees). It shall have a uniform thickness of between1,5mm and2,5mm. NOTEReplace the backing if its edges are worn or the surface damaged. 6 Conditioning Condition the test pieces at standard atmosphere23/50 in accordance with EN20187 and keep them in the conditioning room during the entire test. Figure 2 Force-time curveENV12448:1996 6 BSI 03-1999 7 Preparation of test pieces The size of the test pieces depends on the design of the friction tester. Prepare a number of test pieces
