Abstract:

The mixing room has a high importance in every rubber processing plant. First an own mixing facility empowers the processor to buy his own raw materials. For products with a high part of material costs, the costs for raw materials can be a decisive fact to be / or not profitable.
Second the compounding itself has a strong influence on the quality of the final product. Thus the compounding of elastomers has a big quality and cost impact.
In this paper two aspects for the mixing room are discussed. After a short overview over the typical cost structures in a mill room the sense of optimisations in terms of personal costs, investment and energy costs are contemplated. It shows that energy costs are the only cost category which gives considerable savings also in partly loaded mixing lines.
After this possibilities to save energy costs for a typical mixing line in the tyre industry are shown and introduced in detail. This starts with more effective main drives, energy saving TCU’s and hydraulic instead of pneumatic rams. Also energy saving possibilities for the downstream equipment are considered.
Apart from these direct possibilities, indirect substancial savings can be achieved. Here the better process abilities by the use of a ram-position control are introduced and demonstrated by some examples. It can be shown clearly that by this measure, filler blow-ups onto the ram roof can be avoided and such complete ram lifts can be skipped from the mixing procedure. Also the oil injection can be optimized by the systematic use of the ram position control. In total savings of up to 25% of mixing time (of course dependant on the process itself) can be shown.
Another real big step towards a higher efficiency is the use of the tandem technology. The paper will demonstrate the concept. Some typical examples for tyre compounds show savings of up to 50% of the mixing time. The paper will also demonstrate major qualitative advantages as lower spread of properties, better mechanical values for the compounds and lower porosity of extruded semi-finished products.
Based on these findings the paper will show some typical examples of the use of the tandem technology.
In total the paper has the target to demonstrate some measures to boost the output of mixing lines or at least to optimize existing installations. As already mentioned, also the qualitative aspects will be part of the discussion.
 

Curriculum Vitae    ANDREAS LIMPER

Prof.Dr.Ing. A.Limper was born in 1956 in Altenhundem (now:Lennestadt) and lives in Freudenberg /Germany.He is married and has three children.

Education / Professional Carreer :
1974-1981  study of Mechanical Engineering at the RWTH Aachen
           –branch of study:   Polymer Processing

1981-1985  scientific coworker at the IKV / Aachen under the guidance of Prof.Dr. G.Menges
           –field of work: Rubber Extrusion; Rubber Rheology; Rubber Mixing

1985  Ph.D. at Aachen University (Theme : Rubber Extrusion)

1985-1987  Head of the Extrusion Department of the IKV / Aachen
           –activities of the department (17 working groups) : plastics extrusion;
           PVC processing, Control systems; Die design; Rubber extrusion; Rubber mixing

1987-1989  Head of R&D of Battenfeld Extrusionstechnik; Bad Oeynhausen
           –pipe extrusion ; blown film lines; sheet extrusion ; calendering ;
           granulation machines; profile extrusion

1989-1995 Head of technical Department of Werner & Pfleiderer /Freudenberg
         –Rubber Mixers ; Roll Mills ; Extruders ; Control Systems for Mill Rooms

1992  Venia Legendi for “Rubber Processing” of the University of Aachen

1995-2004 Professor at the University of Paderborn (10 Working groups in the fields
          Rubber Mixing ; Rubber Rheology ; Rubber Extrusion ; Die design;
          Plastics Compounding)

since 2001 Managing Director of the Freudenberg Plant of ThyssenKrupp Elastomertechnik
           (former W&P) in Freudenberg – still holding the Professorship in Paderborn.

since 2004 Member of the Management board of Harburg-Freudenberger Maschinenbau
           (former TK Elastomertechnik)

Miscellaneous:
1991 “Best Paper Award “ at the ACS Conference (Rubber Division) in Detroit / USA
1997 “Erich Conrad Medal” of the German Rubber Association
 
Named as inventor on about 35 Patents concerning Rubber and Plastics Processing
About 150 Publications
About 100 Lectures at National / International Conferences
Author and Editor of several Books concernig Rubber and Plastics Processing