PROCESS TO MAKE ENAMELS

There are three stages in which the enamels are made

Slurry Making

Slurry is made in the High Speed Disperser
In this process the materials are mixed to effect a liquid compound which can be passed through the sand mill. The slurry will consist of, pigment, solvent, resins, thickeners, additive and other materials depending on the formulation. The stirrer shaft which revolves at about 1400RPM dissolves these materials and partly removes the agglomerates, to ensure a smooth liquid with very few blobs of unmixed materials.

Dispersing The Slurry To Homogeneous Material

Once the slurry is made in the High Speed disperser, the same is passed through the sand mill. The principle of sand milling is that each individual pigment particle is separated and is coated with the resin, solvent, binder, thickener, additives in a consistent homogeneous manner.

The slurry is pumped into the sand mill from the bottom with the help of a feed pump. The flow rate is adjusted with the help of mechanical/electrical variator. The pumped liquid is passed through a shell containing grinding media, which is basically glass beads, zirconia beads, steel balls. The shearing action takes places as the slurry is passed through the grinding media. The velocity to the grinding media is given by the shaft with impellers discs fitted to a motor. The shaft rotates at the particular speed imparting velocity to the grinding media, through which the slurry is passed. Shearing action is imparted by friction between the two beads of the grinding media. As the slurry passes through these beads the agglomerates are separated by the shearing action.

As the material is pumped it rises to the top of the shell where the product material is passed through a sieve. The grinding media is separated and only the product material drains out into a collection port and out through the sand mill discharge nozzle.

The finesse can be attained in a single pass or by multiple passes if required. Thus a uniform particle size is achieved.

Thinning and Tinting/Shade Matching

The finished material from the sand mill is passed into the thinning tank. This tank is used basically for getting the consistency of the material and also for tinting or shade matching.

The thinning tank is a slow speed mixer having three sets of paddle blades moving at a fixed speed. Addition of materials like solvent, tinters, resins are added to get the right shade and consistency of the materials.