A stereolithography resin called ProtoCast AF19120 generated significantly less burnout ash when used to make casting patterns for key aerospace parts. The castings that resulted also had fewer flaws that needed weld repair, saving KomTek in Worcester, Mass., about $6.75 per casting in labor. The photopolymer is used to make a 2-lb investment casting through the Quick- Cast method. Normally, foundries burn…