Cast Aluminium Backrest,made by sand casting process,used for outdoor&indoor chair,OEM for oversea market.. Material: aluminum alloy Process: die-casting, sand casting and permanent mold casting (gravity or chill casting) Software for drawing: pro/E, auto CAD, UG, CAD, PDF and solidworks 2008 flow analysis Further machining work: turning and cutting, milling, grinding, drilling, reaming and ...