1、BRITISH STANDARDBS EN ISO 293:2005Plastics Compression moulding of test specimens of thermoplastic materialsThe European Standard EN ISO 293:2005 has the status of a British StandardICS 83.080.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g3
2、8g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 293:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 10 January 2006 BSI 10 January 2006ISBN 0 580 47011 3National forewordThis Britis
3、h Standard is the official English language version of EN ISO 293:2005. It is identical with ISO 293:2004. It supersedes BS EN ISO 293:2003 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/21, Testing of plastics, which has the responsibility to: A
4、list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standa
5、rds Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard d
6、oes not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European develop
7、ments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii to v, a blank page, pages 1 to 6, an inside back cover and a back cover.The BSI copyright notice displayed i
8、n this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 293July 2005ICS 83.080.20 Supersedes EN ISO 293:2003 English VersionPlastics - Compression moulding of test specimens ofthermopla
9、stic materials (ISO 293:2004)Plastiques - Moulage par compression des prouvettes enmatires thermoplastiques (ISO 293:2004)Kunststoffe - Formgepresste Probekrper ausThermoplasten (ISO 293:2004)This European Standard was approved by CEN on 7 July 2005.CEN members are bound to comply with the CEN/CENEL
10、EC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN
11、member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members
12、 are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United K
13、ingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 293:2005: EForew
14、ord The text of ISO 293:2004 has been prepared by Technical Committee ISO/TC 61 “Plastics” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 293:2005 by Technical Committee CEN/TC 249 “Plastics“, the secretariat of which is held by IBN. This European Stand
15、ard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2006, and conflicting national standards shall be withdrawn at the latest by January 2006. This document supersedes EN ISO 293:2003. According to the CEN/CENEL
16、EC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta
17、, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 293:2004 has been approved by CEN as EN ISO 293:2005 without any modifications. EN ISO 293:2005INTERNATIONALSTANDARDISO293Third edition2004-05-01Reference nu
18、mberISO 293:2004(E)Plastics Compression moulding of test specimens of thermoplastic materialsPlastiques Moulage par compression des prouvettes en matires thermoplastiquesEN ISO 293:2005iiiiiContents Page1 Scope 12 Normative references 13 Terms and definitions 14 Apparatus . 25 Procedure . 46 Inspect
19、ion of the moulded specimens or sheets . 67 Specimen preparation report 6EN ISO 293:2005ivForewordISO (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
20、through ISOtechnical committees. Each member body interested in a subject for which a technical committee has beenestablished has the right to be represented on that committee. International organizations, governmental andnon-governmental, in liaison with ISO, also take part in the work. ISO collabo
21、rates closely with the InternationalElectrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standard
22、s. Draft International Standardsadopted by the technical committees are circulated to the member bodies for voting. Publication as anInternational Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this d
23、ocument may be the subject of patentrights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 293 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplasticmaterials.This third edition cancels and replaces the second edition (ISO 293:1
24、986), of which it constitutes a minorrevision intended, above all, to update the normative references (Clause 2).EN ISO 293:2005vIntroductionFor reproducible test results, specimens with a defined state are required. In contrast to injection moulding, theaim of compression moulding is to produce tes
25、t specimens and sheets for machining or stamping of testspecimens that are homogeneous and isotropic.In the process of compression moulding, mixing of material takes place on a negligible scale. Granules andpowders fuse only at their surfaces and preforms (milled sheets) are only partially softened.
26、Isotropic and homogeneous specimens can, therefore, only be obtained when the moulding material is itselfhomogeneous and isotropic. This has to be considered when processing multiphase materials, such as ABS,which retain their internal structure.EN ISO 293:2005viblank1Plastics Compression moulding o
27、f test specimens of thermoplastic materials1ScopeThis International Standard specifies the general principles and the procedures to be followed withthermoplastics in the preparation of compression-moulded test specimens, and sheets from which testspecimens may be machined or stamped.In order to obta
28、in mouldings in a reproducible state, the main steps of the procedure, including four differentcooling methods, are standardized. For each material, the required moulding temperature and cooling methodsare as specified in the appropriate International Standard for the material or as agreed between t
29、he interestedparties.The procedure is not recommended for reinforced thermoplastics.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the
30、referenced document(including any amendments) applies.ISO 286-1, Geometrical product specifications (GPS) ISO coding system for tolerances of linear sizes Part 1: Bases of tolerances and fitsISO 4287, Geometrical Product Specifications (GPS) Surface texture: Profile method Terms, definitionsand surf
31、ace texture parameters3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1 moulding temperaturetemperature of the mould or the press during the preheating and moulding time, measured in the nearestvicinity to the moulded material3.2 demoulding tempe
32、raturetemperature of the mould or the press platens at the end of the cooling time, measured in the nearest vicinity tothe moulded materialNOTE For positive moulds, holes are normally drilled in the mould for measuring the temperatures defined in 3.1 and 3.2.3.3 preheating timetime required to heat
33、the material in the mould up to the moulding temperature while maintaining the contactpressureEN ISO 293:200523.4 moulding timetime during which full pressure is applied while maintaining the moulding temperature3.5 average cooling rate (non-linear)rate of cooling by a constant flow of the cooling f
34、luid, calculated by dividing the difference between moulding anddemoulding temperatures by the time required to cool the mould to the demoulding temperatureNOTE The average cooling rate is usually expressed in degrees Celsius per minute.3.6 cooling rateconstant rate of cooling in a defined temperatu
35、re range obtained by controlling the flow of the cooling fluid insuch a way that over each interval the deviation from this specified cooling rate does not exceed thespecified toleranceNOTE The cooling rate is usually expressed in degrees Celsius per hour.4 Apparatus4.1 Moulding pressThe press shall
36、 have a clamping force capable of applying a pressure (conventionally given as the ratio of theclamping force to the area of the mould cavity) of at least .The pressure shall be maintained to within of the specified pressure during the moulding cycle.The platens shall be capable ofa) being heated to
37、 at least ;b) being cooled at a rate given in Table 1.The difference between the temperatures of any points of the mould surfaces shall not vary by more thanduring heating and during cooling.When the heating and cooling system is incorporated in the mould, it shall comply with the same conditions.Th
38、e platens or mould shall be heated either by high-pressure steam, by a heat-conducting fluid in anappropriate channel system, or by using electric heating elements. The platens or mould are cooled by a heat-conducting fluid (usually cold water) in a channel system.For quench cooling (see method C in
39、 Table 1), two presses shall be used, one for heating during moulding andthe other for cooling.For a specified cooling method, the flow rate of the heat-conducting fluid shall be predetermined in a testwithout any material in the mould.The temperature may be continuously controlled in the centre bet
40、ween the upper and lower platen of the press.4.2 Moulds4.2.1 GeneralThe characteristics of the test specimens prepared by using different types of moulds are not the same. Inparticular, the mechanical properties depend on the pressure applied to the material during cooling.10 min10 MPa10 %240C2C 4CE
41、N ISO 293:20053In general, two types of moulds, “flash moulds” (see Figure 1) and “positive moulds” (see Figure 2), are used forcompression moulding test specimens of thermoplastics.Flash moulds permit excess moulding material to be squeezed out and do not exert moulding pressure on themoulding mate
42、rial during cooling. They are particularly convenient for preparing test specimens or panels ofsimilar thickness or comparable levels of low internal stress.With positive moulds, the full moulding pressure, neglecting friction, is exerted on the material during cooling.The thickness, stress and dens
43、ity of the resulting mouldings depend on mould construction, size of materialcharge and the moulding and cooling conditions. This type of mould produces consolidated test specimens withmoulded surfaces and is therefore particularly suitable for obtaining flat surfaces or suppressing the formationof
44、voids within test specimens.4.2.2 FabricationThe moulds shall be made of materials capable of withstanding the moulding temperature and pressure. Thesurfaces in contact with the material shall be polished to obtain good surface conditions on the specimens(recommended surface roughness , see ISO 4287
45、). Specimen removal can be made easier bychromium plating these surfaces. For specimens of small dimensions, a taper is strongly recommended.Blind holes may be drilled in the mould so that temperature can be measured in the vicinity of the mouldedmaterial by using thermocouples or mercury thermomete
46、rs.Depending on the performance of the press (see 4.1), the moulds may have built-in heating and/or coolingdevices similar to those described for the press platens.An alloy steel, resistant to mechanical shock and heat-treated to provide a tensile strength of , willgenerally be satisfactory for the
47、moulds. However, in the special case of PVC moulding materials, the use ofmartensite stainless steel treated to provide a tensile strength of is recommended.4.2.3 Types4.2.3.1 GeneralThe type of mould used shall be capable of producing test specimens of the types and states specified in theappropria
48、te International Standard for the material or shall be agreed upon between the interested parties.Figure 1 Types of flash (“picture frame”) mouldsFigure 2 Positive-type mould0,16Ra22 200 MPa1 050 MPaEN ISO 293:200544.2.3.2 Flash (“picture frame”) mouldsWith this type of mould, the excess material is
49、 squeezed out and the moulding pressure during cooling is onlyexerted on the frame and not on the material. The thickness in the centre of the mouldings is slightly less thanat the edges due to the shrinkage during cooling. Directly moulded test bars may also have sink marks or voidsif the shrinkage is hindered by sticking of the plastic material to the mould.To overcome these disadvantages, stamping or machining of test specimens from the central part ofcompression-moulded sheets is preferred.For moulding sheets, simple and economical flash mould
