From Batchwise to Continuous Production

Over 150 par­tic­i­pants from approx­i­mate­ly 15 nations came to Stuttgart, Ger­many on13 and 14 Novem­ber 2018, accept­ing their invi­ta­tions to the 2018 Cope­ri­on Extru­sion Days. In keep­ing with the mot­to “Batch to Con­ti”, the con­fer­ence took up an often-dis­cussed cur­rent top­ic in the chem­i­cal indus­try, sur­round­ed in con­tro­ver­sy, that offers enor­mous sav­ings poten­tial, while reli­able infor­ma­tion regard­ing its safe­ty and depend­abil­i­ty often remains unavail­able. Pre­sen­ta­tions by inter­nal and exter­nal experts, plant tours, and live pre­sen­ta­tions gave pro­fes­sion­als in atten­dance new insights into the basics of mod­ern extru­sion with co-rotat­ing twin screw extrud­ers and their enor­mous per­for­mance gains — rel­a­tive to pro­duc­tion vol­ume — ver­sus batch­wise mix­ing and homog­e­niza­tion process­es. Such under­stand­ing serves to aid par­tic­i­pants in deci­sion mak­ing for their own uses. A cen­tral focus of many pre­sen­ta­tions was on main­tain­ing con­stant for­mu­la­tions to meet spec­i­fi­ca­tions using appli­ca­tion-specif­i­cal­ly opti­mized extrud­ers, feed­ing sys­tems, and mon­i­tor­ing sys­tems. Con­crete case exam­ples demon­strat­ed suc­cess­ful con­ver­sions from batch to extrud­er tech­nol­o­gy and the sig­nif­i­cant increas­es in pro­duc­tion capac­i­ty enabled there­by, with at least equal prod­uct qual­i­ty and, in any case, sig­nif­i­cant­ly bet­ter qual­i­ty consistency.
A ZSK 34 Mv PLUS twin screw extrud­er was the cen­tral ele­ment in a demon­stra­tion of HMPSA (Hot Melt Pres­sure-Sen­si­tive Adhe­sive) man­u­fac­tur­ing.  In this exam­ple, a Roll-ex  sys­tem mas­ti­cat­ed rub­ber balls on hand as a for­mu­la com­po­nent so far as to enable con­tin­u­ous extrud­er feeding.
Use of a demon­stra­tion extrud­er with a trans­par­ent plas­tic hous­ing allowed Cope­ri­on Stuttgart’s research & devel­op­ment team to give vis­i­tors the abil­i­ty to see for them­selves how dif­fer­ent­ly designed mix­ing ele­ments ensure com­plete mix­ing of two flu­ids with dif­fer­ent vis­cosi­ties. A CFD (Com­pu­ta­tion­al Flu­id Dynam­ics) flow sim­u­la­tion shown in par­al­lel demon­strat­ed the broad agree­ment between the­o­ry and prac­tice. Cope­ri­on is imple­ment­ing this process in order to eval­u­ate new­ly devel­oped screw ele­ments and mix­tures, among others.
“In the mean­time, con­tin­u­ous process­es are being imple­ment­ed in many indus­tries for count­less appli­ca­tions and mix­tures. The advan­tages of con­sis­tent qual­i­ty at con­cur­rent­ly high­er effi­cien­cy nowa­days are also attrac­tive argu­ments for many users in the chem­i­cal indus­try to poten­tial­ly change over from batch process­es to con­tin­u­ous pro­duc­tion”, said Oliv­er Beis­er, Team Leader of Chem­i­cal Appli­ca­tions of Coperion’s Com­pound­ing & Extru­sion Division.
The vari­ety of ques­tions raised in the forum, as well as the ani­mat­ed dis­cus­sions dur­ing breaks between event blocks, demon­strat­ed how great the need is for infor­ma­tion in this field, and how that need extends far beyond what is avail­able. Time and again, par­tic­i­pants expressed amaze­ment at the ver­sa­tile pos­si­bil­i­ties shown, even in their own com­pa­nies, to increase pro­duc­tiv­i­ty with short-term ROI and increased qual­i­ty con­sis­ten­cy. Of par­tic­u­lar note for par­tic­i­pants was a com­par­i­son of scrap quan­ti­ties that Gui­do Arzt, mem­ber of the glob­al process team at Henkel Adhe­sives & Sealants, elu­ci­dat­ed dur­ing his presentation.
More­over, dur­ing one exten­sive plant tour, par­tic­i­pants at the 2018 Extru­sion Days gleaned an impres­sion of Coperion’s ver­ti­cal inte­gra­tion at its Stuttgart loca­tion, rang­ing from screw ele­ment and extrud­er bar­rel man­u­fac­tur­ing to final assem­bly of twin screw extruders.