Blow molding is a process by which hollow plastic parts such as bottles and other containers are formed. It is also used for forming glass bottles. There are three types of blow molding; extrusion blow molding, injection blow molding and injection stretch blow molding. In all cases the base material is semi melted and introduced into the machinery either as a “parson” or “pre-mold” into which air is blown to push the plastic into the mold. After cooling the mold opens and the part is ejected. In continuous blow molding a knife is used to cut the parsons from each other. A titanium coated trimming knife may also be used to trim off excess material. Removed material is melted for re-use. Dust can be a problem at the knife cutting operation and fume may be present at the blowing and mold release stage. For pure dust, the AAF OptiFlo RS is ideal and for a fume and dust combined the compact RotoClone W is ideal.