EPP ni ngufi yaguye polypropylene, intego ya Epp mbere yo kwaguka ni ugutanga imyanda ya polypropylene kubiti byifuzwa. Mugihe cyo kwaguka, ibisigo bya EPP byagaburiwe mu bwato burimo umufasha kandi bugenzurwa n'ibikoresho byo mu kirere, iyi nyamaswa yitwa Epp mbere. Diameter yibice byiyongera mugihe ubucucike bwa resin iragabanuka. Nyuma yo gusohoka kuva kwagutse, ibisaro byagutse bizatemba binyuze mu kumeneka kugirango ukureho ubushuhe, hanyuma ujye kuri silo.