| 摘要 |
PURPOSE: A Teflon bellows manufacturing method using air pressure is provided to prevent excessive stretching of a starting portion of a corrugated part because a pre-forming step and a complete forming step are separately performed so that the corrugated part is formed at constant thickness. CONSTITUTION: A Teflon bellows manufacturing method using air pressure is as follows. A Teflon tube(TT) is inserted into flanges(110) and both end parts of the Teflon tube are flared. A mold support is inserted between forming molds(130) so that the forming molds are fixed. Upper and lower covers(150) are joined to upper and lower flanges and a core mold(140) is inserted between the covers. A flange assembly formed by assembling the flange, an O-ring(120), the Teflon tube, the core mold, and the covers is heated in an electric furnace at 280-330°C so that the Teflon tube becomes preheated. The pneumatic pressure is supplied to the Teflon tube and the Teflon tube becomes inflated and closely adhered to the forming molds so that the mold support is removed. The Teflon tube is inflated by the pneumatic pressure so that a gradual corrugated part is formed. The upper cover is pushed by a press so that the forming mold is closely adhered and the gradual corrugated part is formed into a perfect shape. The flange assembly is heated again in the electric furnace for 20-50 minutes at 280-330°C. The pneumatic pressure of 6-12kg/cm^2cm^2 is consistently supplied so that the flange assembly becomes cooled.
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