Timing Calculations for Double Puller Systems in Aluminum Extrusion

摘要

Many extruders do not appreciate the requirements imposed on the plant design when deciding to invest and install a double puller system. When a plant is to he installed on a greenfield site, the limitations of design pose no problems, but when equipment is to be installed in an existing building or retrofitted to an existing press, these limitations can be prohibitive. When asked why a double puller is needed, the extruder may answer; "We want the latest technology," or "We want to cut on the fly to eliminate the stop mark." These requirements are made without the realization that double pullers require long leadouts if the extrusion speed capability is to be exploited. Older plants are often limited in length by the dimensions of the building or the proximity of other equipment, and increases in initial table length can only be achieved at the expense of the runout. This may turn out to be unacceptably short.