What Every Engineer Should Know about Graphite Fixturing

For decades successful manufacturers of precision parts used heat-treating fixtures made out of alloys that combined for maximum quantity of components while trying to minimize the fixture weight in supporting the components to obtain a minimal amount of part distortion. The downside however, was that these alloys would become distorted and embrittled from long exposure to temperatures, often resulting in the damage and distortion of the components.  In recent years, more and more heat treating engineers are making the switch to graphite fixturing using carbon fiber composite materials which offer excellent thermal shock resistance and thermal conductivity.  This high thermal stability allows filigree structures to be manufactured with high mechanical strength.  (The strength of graphite actually increases with temperature.)  The complete flatness of this material combined with a low thermal mass affords rapid heat-up and cool-down time, reducing cycle times and providing for longer service life.  This paper discusses the (many) pros and (some) cons of using carbon fiber composite fixturing in the heat treating environment.  It presents insight into the technology of the fixturing from conceptual design to operational working environments that will continue to prove their cost effectiveness for years to come.