Tablet press fill cam

In this article we will learn about tablet press fill cam science behind fill cam its selection and its importance.

Fill cam is critical part of tablet press commonly known as Pull down cam. Tablet press is based upon the principle of overfill and the overfill is achieved using fill cam to lower down the lower punch allowing the die to fill excess blend. Selection of appropriate fill cam is necessary for proper machine running.

Too deep fill cam will take excessive blend which will finally end up in recirculation and too shallow fill cam will be unable to adjust required weight.

Method of determining fill cam.

Tablet press Fill cam

Theoretical Formula for fill cam selection is. Tablet weight in mg/Punch surface area mm² * Bulk density.

Fill cam selected shall be above the size we get using above formula example if using above formula we get value 9.2 mm fill cam used should be of 10 mm.

However, for some selective batches the above formula does not work due to cohesive and sticky nature of product. In such blends the fill cam according to above formula should give 110% of blend is giving only 70% in such cases deeper fill cam must be used.

Fill cams of different vendors

Some vendors like cadmach give fill cam in inches like 5/16 , 7/32 11/16 and most vendors like sejong , Korsch give fill cam in mm. mm is easily understandable mode of checking the filling depth However fill cam in inches could be converted to mm by formula 5*25.4/15 where 25.4 is value of mm in 1 inch.

Can fill cam cause the problem of black spots ?

Consider a situation too deep fill cams are use for product and there is excessive oil on punches plus bad vacuum pickup where would all the particles collected on punches go all these combined can lead to quality issues like Black spots on tablets. so,selection of fill cam shall be done carefully.