Sheet moulding compound (SMC) or sheet moulding composite is a ready to mould glass-fibre reinforced polyester material primarily used in compression moulding.[1] The sheet is provided in rolls weighing up to 1000 kg. Alternatively the resin and related materials may be mixed on site when a producer wants greater control over the chemistry and filler.
SMC is both a process and reinforced composite material. This is manufactured by dispersing long strands (usually >1”) of chopped fiber, commonly glass fibers or carbon fibers on a bath of thermoset resin (typically polyester resin, vinyl ester resin or epoxy resin). The longer fibers in SMC result in better strength properties than standard bulk moulding compound (BMC) products. Typical applications include demanding electrical applications, corrosion resistant needs, structural components at low cost, automotive, and transit.
Paste reservoir dispenses a measured amount of specified resin paste onto a plastic carrier film. This carrier film passes underneath a chopper which cuts the fibers onto the surface. Once these have drifted through the depth of resin paste, another sheet is added on top which sandwiches the glass. The sheets are compacted and then enter onto a take-up roll, which is used to store the product whilst it matures. The carrier film is then later removed and the material is cut into charges. Depending on what shape is required determines the shape of the charge and steel die which it is then added to. Heat and pressure act on the charge and once fully cured, this is then removed from the mould as the finished product. Fillers both reduce weight and change the physical properties, typically adding strength. Production challenges include wetting the filler, which could consist of glass microspheres or aligned fibers rather than random chopped fibers; adjusting die temperature and pressure to provide the proper geometry; and adjusting chemistry to end use.
Advantagesedit
Compared to similar methods, SMC benefits from a very high volume production ability, excellent part reproducibility, it is cost effective as low labor requirements per production level is very good and industry scrap is reduced substantially. Weight reduction, due to lower dimensional requirements and because of the ability to consolidate many parts into one, is also advantageous. The level of flexibility also exceeds many counterpart processes.
Physical propertiesedit
Properties vary depending upon filler and resin types, with compounds using aligned fibers (especially long fibers) being subject to greater anisotropy. Typical ranges are listed below.[2][3][4][5]
^Whelan, A. (2012). Polymer Technology Dictionary. Springer Science & Business Media. p. 391. ISBN9789401112925.
^AZO Materials (21 August 2001). "Polyester - SMC; High Impact". AZO Materials. Retrieved 23 December 2018.
^Trauth, Anna; Pinter, Pascal; Weidenmann, Kay (December 2017). "Investigation of Quasi-Static and Dynamic Material Properties of a Structural Sheet Molding Compound Combined with Acoustic Emission Damage Analysis". Journal of Composites Science. 1 (2): 18. doi:10.3390/jcs1020018.
^Hager, William; Young, John (16 January 1998). "Session 5-C". SPI/CI International Conference and Exposition 1998. CRC Press. pp. 1–9. ISBN9781566766425.
^"Sheet Molding Compounds, Bulk Molding Compounds". www.idicomposites.com. IDI Composites International. Retrieved 23 December 2018.
This material-related article is a stub. You can help Wikipedia by expanding it.
sheet, moulding, compound, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, . This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Sheet moulding compound news newspapers books scholar JSTOR January 2018 Learn how and when to remove this message Sheet moulding compound SMC or sheet moulding composite is a ready to mould glass fibre reinforced polyester material primarily used in compression moulding 1 The sheet is provided in rolls weighing up to 1000 kg Alternatively the resin and related materials may be mixed on site when a producer wants greater control over the chemistry and filler SMC is both a process and reinforced composite material This is manufactured by dispersing long strands usually gt 1 of chopped fiber commonly glass fibers or carbon fibers on a bath of thermoset resin typically polyester resin vinyl ester resin or epoxy resin The longer fibers in SMC result in better strength properties than standard bulk moulding compound BMC products Typical applications include demanding electrical applications corrosion resistant needs structural components at low cost automotive and transit Contents 1 Process 2 Advantages 3 Physical properties 4 See also 5 ReferencesProcess editPaste reservoir dispenses a measured amount of specified resin paste onto a plastic carrier film This carrier film passes underneath a chopper which cuts the fibers onto the surface Once these have drifted through the depth of resin paste another sheet is added on top which sandwiches the glass The sheets are compacted and then enter onto a take up roll which is used to store the product whilst it matures The carrier film is then later removed and the material is cut into charges Depending on what shape is required determines the shape of the charge and steel die which it is then added to Heat and pressure act on the charge and once fully cured this is then removed from the mould as the finished product Fillers both reduce weight and change the physical properties typically adding strength Production challenges include wetting the filler which could consist of glass microspheres or aligned fibers rather than random chopped fibers adjusting die temperature and pressure to provide the proper geometry and adjusting chemistry to end use Advantages editCompared to similar methods SMC benefits from a very high volume production ability excellent part reproducibility it is cost effective as low labor requirements per production level is very good and industry scrap is reduced substantially Weight reduction due to lower dimensional requirements and because of the ability to consolidate many parts into one is also advantageous The level of flexibility also exceeds many counterpart processes Physical properties editProperties vary depending upon filler and resin types with compounds using aligned fibers especially long fibers being subject to greater anisotropy Typical ranges are listed below 2 3 4 5 Density 1 1 2 0 g cm3 69 125 lb cu ft Impact Strength 4 11 J cm 7 21 ft lbf in Flexural Strength 120 230 MPa 17 33 ksi Flexural Modulus 10 15 GPa 1 500 2 200 ksi Tensile Strength 55 125 MPa 8 18 ksi Tensile Modulus 7 14 GPa 1 000 2 000 ksi Compressive Strength 130 220 MPa 19 32 ksi Heat Deflection Temperature at 1 82 MPa 264 psi 200 260 C 392 500 F Heat Deflection Temperature at 0 455 MPa 66 psi 115 180 C 239 356 F Curing Temperature 80 150 C 176 302 F See also editBulk moulding compound Fiberglass Fibre reinforced plastic Thermosetting polymer Thermoset polymer matrix Forged composite CFSMCReferences edit Whelan A 2012 Polymer Technology Dictionary Springer Science amp Business Media p 391 ISBN 9789401112925 AZO Materials 21 August 2001 Polyester SMC High Impact AZO Materials Retrieved 23 December 2018 Trauth Anna Pinter Pascal Weidenmann Kay December 2017 Investigation of Quasi Static and Dynamic Material Properties of a Structural Sheet Molding Compound Combined with Acoustic Emission Damage Analysis Journal of Composites Science 1 2 18 doi 10 3390 jcs1020018 Hager William Young John 16 January 1998 Session 5 C SPI CI International Conference and Exposition 1998 CRC Press pp 1 9 ISBN 9781566766425 Sheet Molding Compounds Bulk Molding Compounds www idicomposites com IDI Composites International Retrieved 23 December 2018 nbsp This material related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Sheet moulding compound amp oldid 1093725548, wikipedia, wiki, book, books, library,
