1、WORLDWIDEENGINEERINGSTANDARDSTest Procedure GMW14773Test Method for Determining the Dimensional Stability ofFiberboards, Cardboard, and Similar Rigid Materialsunder Humid Conditions Copyright 2013 General Motors Company All Rights ReservedFebruary 2013 Page 1 of 31 ScopeNote: Nothing in this standar
2、d supercedes applicable laws and regulations.Note: In the event of conflict between the English and domestic language, the English language shall takeprecedence.1.1 Purpose. This standard shall be used to determine the shape retention characteristics of fiberboards,cardboard and similar materials wh
3、en subjected to specific temperature and humidity conditions.1.2 Foreword. Not applicable.1.3 Applicability. Not applicable.2 ReferencesNote: Only the latest approved standards are applicable unless otherwise specified.2.1 External Standards/Specifications.None2.2 GM Standards/Specifications.None3 R
4、esources3.1 Facilities.3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a validcalibration label.3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuringvariables as specified in this standard shall be de
5、termined correctly with respect to their physical definition.3.1.3 Humidity cabinet with air circulation, adjustable, capable of maintaining a temperature of (+40 3) Cand a relative humidity of (95 5) %.3.2 Equipment.3.2.1 Cutting dies or shears for preparation of test pieces.3.2.2 Pan (for containi
6、ng test pieces) of internal dimensions (254 +10/-0) mm x (400 10) mm with verticalwalls of 30 mm height, (material optional provided that it is unaffected by the test environment e.g.aluminium).3.2.3 Vernier callipers accurate to 0.1 mm.3.3 Test Vehicle/Test Piece.3.3.1 From the available material,
7、test pieces (254 + 0/-0.2) mm x (40 0.2) mm shall be taken from twodirections perpendicular to one another. If material is bowed the longer dimension shall be the chord of thesector produced by placing the test piece on a flat surface.3.3.2 For initial sample approval and arbitration purposes six te
8、st pieces minimum from each direction, and forroutine quality control three test pieces minimum from each direction shall be tested.3.4 Test Time. Not applicable.Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking perm
9、itted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14773 Copyright 2013 General Motors Company All Rights ReservedFebruary 2013 Page 2 of 33.5 Test Required Information. Not applicable.3.6 Personnel/Skills. Not applicable.4 Procedure4.1 Preparation. For initial sample approval,
10、 arbitration purposes and routine quality control, test pieces shallbe tested in the as received condition (i.e., no special preconditioning).4.2 Conditions.4.2.1 Environmental Conditions. See paragraph 4.3.4.2.2 Test Conditions. Deviations from the requirements of this standard shall have been agre
11、ed upon. Suchrequirements shall be specified on component drawings, test certificates, reports, etc.4.3 Instructions.4.3.1 The test pieces shall be placed in the test pan such that the longitudinal dimension is across the 254 mmdimension of the pan, and that the test pieces are not in contact with o
12、ne another. Any bowing of the test pieceshall be measured with the calipers and noted as the datum for subsequent measurements.4.3.2 The pan and contents shall be maintained in the humidity cabinet for (24 +0.5/-0) h at a temperature of(+40 3) C and a relative humidity of (95 5) %.4.3.3 After the ab
13、ove treatment any convex bowing (See Figure 1) of the test piece shall be measured as thevertical distance (X) max. from the pan bottom to the underside of the test piece to the nearest 0.1 mm.Figure 1: Convex Bowing4.3.4 Where concave bowing (See Figure 2) is observed the test piece shall be revers
14、ed in the pan andmeasurement of bowing performed as above.4.3.5 All calculations of bowing shall take into account any initial bowing of the test piece.Figure 2: Concave Bowing5 Data5.1 Calculations. Not applicable.5.2 Interpretation of Results. The dimensional stability shall be evaluated in terms
15、of bowing height, indicatedas a percentage of the vertical distance (X) to the test piece length as follows:5.3 Test Documentation.5.3.1 With reference to this test method, the bowing height shall be indicated as the arithmetical mean valuerounded to the nearest 0.5 %, expressed as a maximum value f
16、or either direction and also as the sum ofbowing heights for both directions.5.3.2 The highest value obtained in each instance shall not exceed that quoted on the relevant drawing ormaterial specification.XXCopyright General Motors Company Provided by IHS under license with General Motors CompanyNot
17、 for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14773 Copyright 2013 General Motors Company All Rights ReservedFebruary 2013 Page 3 of 36 SafetyThis standard may involve hazardous materials, operations, and equipment. This standar
18、d does not propose toaddress all the safety problems associated with its use. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and determine the applicability of regulatory limitations priorto use.7 Notes7.1 Glossary.Dimensional Stability: is
19、the shape retention characteristics as determined by this test method and shall bedefined as the ability of test materials to retain their shape when subjected to the test environment, under freestanding (i.e., not mechanically stressed) conditions.7.2 Acronyms, Abbreviations, and Symbols. Not appli
20、cable.8 Coding SystemThis standard shall be referenced in other documents, drawings, etc., as follows:Test to GMW14773On drawings, material specifications, etc., the dimensional stability shall be indicated as follows:Example:Dimensional Stability to GMW14773Bowing height in one direction 0.6 % max.
21、Bowing height sum of both directions 1.0 % max.9 Release and RevisionsThis standard was originated in November 2005. It was first approved by Global Textile SSLT inNovember 2006. It was first published in July 2007.Issue Publication Date Description (Organization)1 JUL 2007 Initial publication.2 FEB 2013 5 year refresh update (Textile GSSLT)Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
