ISO 8605 pdf download.Textile-glass-reinforced plastics — Sheet moulding compound (SMC) — Basis for a specification
1 Scope
This International Standard establishes a basis for a specification for sheet moulding compound (SMC) used in the production of composite parts by hot moulding. It applies only to sheet moulding compound having glass fibres as the sole or main reinforcement. It should be noted that the term sheet moulding compound covers products which can be complex mixtures and which may differ from the definition of “mat” given in ISO 472.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 62:1 999, Plastics — Determination ofwaterabsorption. ISO 75-2:— 1 ) , Plastics — Determination oftemperature ofdeflection underload— Part2: Plastics andebonite. ISO 1 79-1 :2000, Plastics — Determination ofCharpy impactproperties — Part1: Non-instrumentedimpacttest. ISO 1 79-2:1 997, Plastics — Determination ofCharpy impactproperties — Part2: Instrumentedimpacttest. ISO 1 80:2000, Plastics — Determination ofIzodimpactstrength. ISO 291 :1 997, Plastics — Standardatmospheres forconditioning andtesting. ISO 472:1 999, Plastics — Vocabulary. ISO 527-4:1 997, Plastics — Determination of tensile properties — Part4: Test conditions for isotropic and orthotropic fibre-reinforcedplastic composites. ISO 1 1 72:1 996, Textile-glass-reinforced plastics — Prepregs, moulding compounds and laminates — Determination ofthe textile-glass andmineral-fillercontent — Calcination methods.
3 Term and definition
For the purposes of this International Standard, the following term and definition apply. 3.1 sheet moulding compound SMC a homogeneous mixture of resin and chopped and/or unchopped reinforcement, with or without fillers, produced in sheet form in thicknesses generally between 1 mm and 25 mm, and capable of being cured by moulding under heat and pressure NOTE Additives may be added to the mixture to obtain an SMC with specific properties.
4 Classification of SMC
4.2.2 Reinforcement(s) 4.2.2.1 Form Although this International Standard covers only glass reinforcements, other types may nevertheless be used together with the main (glass) reinforcement. The glass reinforcement generally takes the form of chopped or unchopped strands, used alone or in combination with continuous yarns deposited in various ways, depending on the properties required for the parts to be produced from the SMC (e.g. continuous-strand mats, looped-strand mats). 4.2.2.2 Strand length With isotropic reinforcements produced using chopped strands, the length varies from one type of SMC to another (usually 25 mm and/or 50 mm). The length of the chopped strands shall be stated in the specification. With directional reinforcements, the fibres may be continuous or discontinuous, with lengths varying between 1 0 cm and 40 cm. The orientation of these directional fibres is generally such that their ends are distributed in a homogeneous manner in a direction longitudinal to the sheet or to the roll of SMC (i.e. staggered). 4.2.2.3 Proportion of reinforcement Sheet moulding compound may contain between 1 5 % by mass and 70 % by mass of reinforcing material. The proportion of reinforcement shall be stated after the designation of the type of SMC. 4.2.3 Modes of reinforcement 4.2.3.1 General Depending on the length of the fibres (i.e. whether they are chopped or not) and their orientation, distinction can be made between the following types of SMC. 4.2.3.2 SMC-R (R = random) This type of SMC is produced using strands chopped and deposited without preferential orientation. This is the type called “standard”, which permits flow in all directions and has mechanical properties which are average and isotropic. EXAMPLE SMC-R containing 40 % by mass of reinforcement is designated SMC-R40.