Filled grades shrinkage

The manufacturers stress ease of processing as a particular feature of the material. Recommended melt temperatures are in the range 320-340°C and mould temperatures are 135-165°C. Mould shrinkage of glass-filled grades is usually of the order of 0.2-0.4% in the flow direction and up to twice this value in the transverse direction. The materials are notable for their ability to withstand vapour phase and infrared soldering processes. 

A low moulding shrinkage (0.005-0.007 cm/cm) in unfilled grades down to about 0.002 cm/cm in 30% glass-fibre-filled grades. 

Open-pit zinc mining is not common, since most mines ate below the surface. The Kidd Creek Mine in Ontario, Canada, is a combination open-pit—underground mine. It is one of the richest deposits in the world with an estimated 62.5 x 10 t grading 7.08% zinc, 1.33% copper, and 151 g silver (14). Underground mining methods include room-and-pdlar, shrinkage, cut-and-fill, and square set. In the United States, ca 20 mines account for more than 98% of zinc production. 

Glass-reinforced grades of SAN exhibit a modulus several times that of the unfilled polymer and, as with other glass-filled polymers, a reduced coefficient of thermal expansion and lower moulding shrinkage. The materials are thus of interest on account of their high stiffness and dimensional stability. 

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