Mixing Process

For precision & consistency.

Divekar Wallstabe & Schneider / Know-How / Mixing Process

Mixing Process


Two types of rubber mixing processes are used at DW&S. We are currently using in excess of 75 compound

formulations and the process of development of new ones as per customer requirements is continuously

on-going. Technical assistance from our JV partners with respect to compound development, production and

testing is taken as per customer needs.


We use a heavy duty, 45 litres Internal Mixer for preparing rubber compounds required in large quantities. The

Synthetic Rubber elastomer, fillers like carbon black and other chemicals as per the formulation are weighed

with a computer aided semi-automatic weighing system.


The system is pre-programmed with the designed recipe. It has suitable interlocks to avoid omissions

and undesired additions. When the raw materials are weighed and ready, they are loaded in the internal

mixer where the rotors operate in enclosed chamber. The mixing is done at controlled temperature.


The next step is done after a set ageing time in which the mass of raw compound is again rolled with

curing agents (accelerators). This compound is then moved through rollers to give sheets of desired thickness.


The second mixing process, which is manual, is done on open type roller mills and is mainly used for small

quantities or coloured compounds. 


The compound is then tested in the laboratory for various routine and type tests depending on the specifications. 

A few of examples are hardness tests, rheological tests, compression set tests, ageing tests in air and various

other media.


On successful completion of the tests the compound is issued to the next process.