"We at Micro vision Enterprises are committed to
achieve customer satisfaction by manufacturing
consistent quality Rubber Testing Machines and providing
continually improved service after sale This is
achieved through adherence to ISO 9001 : 2000 quality policy and active participation of employees and associates.
The oscillating Disc type Rheometer is an efficient, simple and reliable testing equipment. It is quite easy to operate. The Rheometer describes precisely and quickly curing and processing characteristics of
vulcanizable rubber compounds. It works on a very simple principle. A test piece of rubber compound is contained in a sealed test cavity under positive pressure and maintained at a specified elevated temperature. A Rotor ( biconical disc )is embedded in the test piece and is oscillated through a small specified rotary amplitude. This action exerts a shear strain on the test piece and the torque (force) required to oscillate the disc depends upon Stiffness (shear modulus) of the rubber compound.
The stiffness of the specimen compound increases when
cross links are formed during cure. The direct Proportionately posited between the shear modulus and the cross linking density is based on the statistical theory of rubber elasticity .At a constant temperature of the test, a cross linking isotherm is the function of time of that property which serves
to measure the course of the cross linking reaction. In the context of
Rheometer, the cross linking isotherm is thus the function of time, of the oscillating shear force F, or of the Rheometer indication proportional to it, occurring at a given temperature as a result of
vulcanization. A plot of this torque (force) value against time gives a typical graph called "Cure Curve or
Rheograph". A trained eye
can monitor the initial trough i.e. processing behavior of the compound, the slope of rise during cure phase i.e. curing characteristics and final shape of the curve. Internationally designated parameters
like MI, MH, TS2, TS5, TC50, TC90 etc. are markers which can be used to describe a graph. The Cure Curve obtained with Rheometer is a finger print of compound's
vulcanization & processing character.
In order to produce consistent quality of rubber product, it is of vital importance that compounded rubber is of consistent quality. The
process of mixing is subject to variations due to
a) Ingredients variations
b) Machinery variation
c) Man variation
d) Batch to batch variation
as the compound is mixed in batches. To minimize the effect of above four variables one has to design technique to overcome it. If randomly selected batches are subjected to Rheometeric analysis, one could in a large sample size, workout upper and lower control limits, range, mean and standard deviation, with reference to Rheological parameters.
Each batch on testing can be classified in Pass/Fail criteria depending upon the quality control limits. Based on this, the internationally acceptable control called "Statistical Quality Control"
(SQC) can be designed. One can also design quality control gates which can be marked on the screen so that a quick decision can be made regarding acceptability or rejection . Rheometer is a versatile instrument and of numerous applications . A compounder can use it to his advantage in areas like development of new compound,
rationalization of existing compound both in terms of quality and economics, optimization of curing process in the manufacturing process to get a better yield. It is
up to the user to design his own techniques with the help of this excellent tool to suit his process.