1、SI BSXqBLB 33 D Lb24bb9 0353552 933 m BRITISH STANDARD Method for Determination of the creasing quality of carton board (Pira method) UDC 676.27.017 BS 4818 : 1993 BSI BS*4818 93 W 1624bb9 0353553 87T W BS 4818 : 1993 Committees responsible for this British Standard Amd. No. Date First published Jul
2、y 1972 Second edition April 1993 The preparation of this British Standard wm entrusted by the Paper and Printing Standards Policy Committee (PAM/-) to Technical Committee PAM/ll, upon which the following bodies were represented: Rxt affected British Carton Association British Fibreboard Packaging As
3、sociation British Paper and Board Industry Federation British Printing Industries Federation British Textile Confederation Envelope Makers and Manufacturing Stationers Association Her Majestys Stationery Office Institute of Paper Conservation Pira International Post Office University of Manchester (
4、Institute of Science and Technology) Coopted member This British Standard, having been prepared under the direction of the Paper and Printing Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 April 1993 Amendments issued since publicatio
5、n The following BSI references relate to the work on this standard: Committee reference PAM111 Draft for comment 92/43100 DC ISBN O 580 21632 2 SI BSX4818 93 Lb24bb 0353554 706 BS 4818 : 1993 Contents Committees responsible Foreword Page Inside front cover 2 Method Introduction 1 Scope 2 Normative r
6、eferences 3 Definition 4 Principle 5 Apparatus 6 Sampling 7 Conditioning 8 Preparation of test pieces 9 Procedure 10 Reproducibility of results 11 Est report 3 3 3 3 3 3 3 3 4 4 6 6 ables 1 Instrument settings 2 Groove number equivalent of groove widths 4 6 Figures 1 Back of board cracks 5 2 Liner c
7、racks 5 3 Pressure ridges 5 List of references Inside back cover This British Standard has been prepared under the direction of the Paper and Printing Standards Policy Committee. It supersedes BS 4818 : 1972, which is withdrawn. The ability of carton board to accept creases without damage in the vic
8、inity of the crease is an important requirement for the conversion of the board into cartons. The width and depth of the creasing groove (or channel) are important variables and the method described in this standard provides a laboratory means of altering these variables so as to help predict the cr
9、easing quality of the board and reduce both the trial and error in make-ready that can occur and the production of faulty cartons. There are several designs of instrument available for carrying out laboratory creasing, but the carton board creaser developed by Pira international is one of the best k
10、nown and is widely used in the United Kingdom. Grateful acknowledgement is made to Pira International for permission to reproduce the creasing defects illustrated in this publication. Compliance with a British Standard does not of itself confer immunity from legal obligations. ES1 BS*48L8 93 = Lb24b
11、b 0353555 642 BS 4818 : 1993 Foreword 2 BS 4818: 1993 Method Introduction The creasing range found gives a direct indication of the quality of a board for carton creasing. The wider the range, the easier it wili be for the converter to find acceptable settings on the cutting and creasing press. In v
12、iew of the many variations in carton size, cutting and creasing presses, make-ready materials and board, it is inadvisable to lay down rules as to the range that is acceptable for different grades of board in this test. The full benefit from this test will be realized only when the user relates the
13、results obtained on the instrument to the performances of the boards on his own converting equipment. Similarly, the boardmiii without converting equipment will find it beneficial to correlate miil test results with reports on performance supplied by customers. When a carton manufacturer wishes to u
14、se the creaser to assist with correct make-ready settings, again the link between test results and practice is necessary. Particular attention should be paid to the differences in the crease conditions that the tester reveals as necessary for the machine and cross directions. 1 Scope This British St
15、andard describes a method of test that provides a numerical assessment of the creasing qualities of carton board. The test can be applied to board materials that would normally be converted into cartons on cutting and creasing presses. 2 Normative references This British Standard incorporates, by re
16、ference, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standard o
17、nly when incorporated in it by updating or revision. 3 Definition For the purposes of this British Standard the following definition applies. creasing quality The minimum and maximum widths of groove that will give satisfactory folds at a given depth of crease under specified conditions. NUTE. A sat
18、isfactory fold is described in terms of the appearance of 180 O hand folds. 4 Principle A test piece is creased in a hand-operated platen press to give creases of specified width and depth. The creased test piece is examined for visible faults at the crease then folded through 180 O away from the cr
19、ease and again examined for faults. 5 Apparatus 5.1 Carton board creaser, consisting of a smaii, hand-operated1) platen press adapted to take the two parts of a creasing die. The upper platen is fitted with a chase containing three parallel creasing rules, each 75 mm long and whose distances apart c
20、an be altered from 12.5 mm to 83 mm by moving the furniture that spaces them. These three creasing rules shall be either 2, 3 or 4 points thick (0.71 mm, 1.07 mm and 1.42 mm respectively) according to the thickness of the board to be tested. The lower platen has a corresponding set of creasing groov
21、es machined in steel strips. Grooves of width 1.40 mm, 1.90 mm, 2.41 mm and 2.79 mm are placed, as specified for the board thickness (see table i), below the outer two rules. Sixteen alternative grooves are available for the central position; these range in width from 1.00 mm in steps of 0.13 mm up
22、to 2.54 mm and in steps of 0.25 mm up to 4.06 mm. The grooves are known by numbers corresponding to their widths in units of 25.4 pm (see table 2). The depth of crease is indicated on a dial gauge fitted to the upper platen, when the operating handle is in the mid-position. The crease depth setting
23、has a screw adjustment that can be locked at the required value during a test. NX. The dimensions of the instrument are converted from the imperial dimensions to which it was originally designed. 6 Sampling Specimens shall be selected as described in BS 3430 : 1986. 7 Conditioning When required, the
24、 specimens shall be conditioned in accordance with BS 3431 : 1973. NOTE. Changes in board moisture content affect the folding and cracking behaviour of carton boards. It is therefore recommended that the conditioning procedure be used whenever it is intended to carry out comparative tests. I) Inform
25、ation on the availability of suitable equipment can be obtained from Customer Services, Information Services Group, BSI, Linford Wood, Milton Keynes MK14 6LE. 3 BSI BSS48L8 93 m 1624669 0353557 415 m BS 4818 : 1993 8 Preparation of test pieces If possible prepare the test pieces in Le same condition
26、ing atmosphere used to condition the specimens. Cut from the specimens at least 10 test pieces not less than 250 mm in length in each of the principal directions of the board. For cross-direction folds, i.e. where the crease is at right angles to the machine direction the test pieces shall be 50 mm
27、wide and for machine direction folds the test pieces shall be 73 mm wide. This width difference will help to equalize the creasing pressures for the two directions. 9 Procedure 9.1 Calibration Place a set of rules in the upper chase and the corresponding set of grooves in the lower. Turn the capstan
28、 screw as far to the right as possible to raise the upper platen. Turn the centre groove in the lower chase upside down. Turn the operating handle so that the upper platen is at the lower limit of the creasing stroke and hold in position. Gently turn the capstan screw to the left to lower the upper
29、platen until the centre creasing rule is brought into contact with the base of the upturned centre groove. With the centre rule in contact with the upturned centre groove, the dial gauge should read zero. If this is not so, unlock the bezel of the dial gauge and rotate it to zero against the pointer
30、. Relock the bezel in the new position. Raise the upper platen and turn the centre groove back over into its correct position under the central rule. NOTE. When calibrated in this way, a dial gauge reading of zero indicates that the rules come level with the upper surface of the grooves at the limit
31、 of the creasing stroke. A negative reading indicates that the rule does not reach the groove and a positive reading indicates entry of the rule into the groove. 9.2 Making the crease NOTE. The manner in which a test is carried out depends to some extent on the use to be made of the results obtained
32、. For quality control purposes, tests may be made on the board as taken, but if it is desired to predict creasing press settings then the sample should be in the printed or printed and varnished state in which it is received by the press operator. In view of the effect of moisture content (see claus
33、e 7) it is recommended that the board is always conditioned prior to testing. 9.2.1 Carry out the test in the same conditioning atmosphere used to condition the specimens. Set up the press with rules and grooves appropriate to the board thickness. NUE. For quality control, these can be standardized,
34、 and suggested settin are shown in table 1. Here the distance between the creases is 50 mm, but this may be varied if a particular carton size is involved. 9.2.2 Check the crease depth whilst making a trial crease with a board test piece in place. If on operating the press the required crease depth
35、is not indicated on the gauge, adjust the crease depth by turning the capstan screw. Check the crease depth for each variation of groove width. 9.2.3 Make a series of creases, with the liner (or top surface) in contact with the creasing rules, varying the width of the central or measuring groove. In
36、 operating the press, move the handle smartly between its extreme positions without pausing at the mid-position. Do not make the crease with such rapidity that the ram strikes hard on its upper limit stop. Remove the creased test piece. bble 1. Instrument settings Board thickness range Pm 350 to 460
37、 470 to 560 570 to 870 880 to 1020 Width of rule point 4 1.42 Depth of crease: dial gauge setting fim + 50 + 50 + 25 O Number of outer (or clamp grooves 55 75 95 110 Width of outer (or clamp) grooves mm 1.40 1.90 2.41 2.79 4 BSXV818 93 m lb24bb 0353558 351 m BS 4818 : 1993 9.3 Examination 9.3.1 With
38、out folding the test piece examine the groove impression on the back of the test piece. A faulty crease will show a crack along the centre of the raised ridge (see figure 1). Figure 1. Back of board cracks 9.3.2 Fold the crease through 180 O away from the top surface by hand and press shut between f
39、inger and thumb, then open out to 90 O and examine, by using a low power microscope if necessary, the liner for cracking (see figure 2). NOTE. Coated boards may show hair line cracks parallel to the fold direction. Figure 2. Liner cracks a) Beside main raised rib b) Along grain crumpled rib c) Acros
40、s grain crumpled rib Figure 3. Pressure ridges 9.3.3 If the folds are satisfactory continue the test using both wider and narrower grooves than the initial choice until faults appear. If the folds show either cracking of the back or liner or a pressure ridge, proceed by using wider grooves. If the f
41、olds show a crumpled rib, proceed by using narrower grooves. NOTE. The amearance of a wide fold differs in t.he machine and cross dirctions. If liner cracking is absent reverse the test piece and examine the inside of the fold for either pressure ridges besides the main raised rib or a crumpled appe
42、arance to that rib (see figure 3). 5 BSI BS*48L8 93 m Lb29669 0353559 298 m BS 4818 : 1993 9.3.4 Record the minimum and maximum groove widths (see table 2) and crease depth for satisfactory folds and the nature of the faults which limit this range. NOTE. The identification across grain should be use
43、d for creases made at nght angles to the machine direction of the board and along grain for creases made parallel to the machine direction. Lgble 2. Groove number equivalent of groove widths Groove number 40 45 50 55 60 65 70 75 80 85 90 95 100 110 120 130 140 150 160 Width mm 1.02 1.14 1.27 1.40 1.
44、52 1.65 1.78 1.90 2.03 2.16 2.29 2.41 2.54 2.79 3.05 3.30 3.56 3.81 4.06 - 10 Reproducibility of results In tests of this nature, for which the end point depends on a subjective assessment of a hand fold, variability in the results may be due to one or more of the following: a) instrument variabilit
45、y; b) errors in setting the crease depth; c) variability in the board samples; d) test operator effects. For some applications of the results, a knowledge of item c) may be important and it is possible to design experiments to study this effect. In all work it is important that items a), b) and d) s
46、hould be reduced to a minimum and to this end proper instruction of the test operators is essential. 11 Test report The test report shall include the following particulars: a) reference to this standard, i.e. BS 4818 : 1993; b) precise identification of the sample; including whether plain, printed,
47、etc.; c) whether or not the sample was conditioned and the conditioning atmosphere used; d) sample thickness; e) creasing rule thickness, rule separation and crease depth; f) minimum and maximum groove widths avoiding the faults illustrated; g) the types of faults to which the sample is prone; h) an
48、y departure from the procedure described in this standard, together with any circumstances or influences that may have affected the results. 6 SI BSXLIBLB 93 m 1ib24bb9 0353560 TOT BS 4818 : 1993 List of references (see clause 2) Normative references BSI standards publications BRITISH STANDARDS INST
49、ITUTION, London BS 3430 : BS 3431 : 986 973 Meth d for samplin to detemzine the average quality of paper and board Method for the conditioning of paper and board for testing ES1 BS+4838 93 m 3b BS 4818 : 1993 BSI 2 Park Street London W 1A 2BS BSI Linford Wood Milton Keynes MK14 6LE 9304- 5- 0.6k- B 4bb9 0353563 94b m BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Contract requireme
