Fill cams are the most important and critical parts of the tablet compression machines.
Compression machines are used to compress the powder or granules to produce the tablets and during this process the weight of the tablets is one of the most important factors which must be as per the weight mentioned in the batch manufacturing record.
The weight of the tablet is greatly affected by the amount of powder or granules filled in the die cavities, if the die filling is not proper and uniform it will result in weight variation & hardness issues.
What is fill cam?
Fill cam is the part of the tablet compression machine which controls the filling of powder and granules in the die bore & ultimately regulate the tablet weight.Fill cams are available in different sizes and usually are available in 6 mm to 22 mm.For small weight tablets the lower number of cams are used & for large size tablets the upper size is used as per the requirement.
Role of Fill Cam
Fill cam plays an important role during tablet compression and following are some key roles of fill cam
- Control of filling depth
- Control of punch movement
- Die filling
- Die Overfilling
- Weight uniformity
Control Of Filling Depth
How deep the tip of the lower punch will be in the die cavity is determined by the fill cam,if punch tip is at lower level of die bore the filling depth will be high & more powder will be filled in the die cavities & vice versa.The die bores are overfilled & excessive power is removed by the dosing cam.
Control of Punch movement
The fill cam also controls the movement of lower punches after tablet ejection.When the tablet from die is ejected the fill cam pulls down the lower punch & again makes a space for powder filling when die passes below the feeder.
Die Filling
Die filling is controlled by the fill cam as it guides the lower punch to its lowest position during the filling stage and ensures maximum filling of the die cavity.
Overfill Die Cavities
The fill cam is designed in such a way that it results in overfilling of the die cavities and excessive power is removed by the dosing cam.
Why Fill Cam Must Be Accurate
The tablet weight & compression force are deeply dependent on the fill cam, so if the fill cam is rightly selected and positioned at its right place it will result in production of good quality tablets but if the fill cam is worn out or the size selection is wrong it will result in following issues,
- Weight variation
- Under filled dies
- Powder wastage
Weight variation
If the fill cam is worn out or not properly selected or wrongly installed, it will result in improper filling of the die cavities which will result in weight variation issues.
Under filled dies
If dies remain under filled means don’t receive proper amount of the powder or granules it will result in production of fragile or low hardness tablets.
When To Replace Fill Can
The fill cams must be inspected at regular time intervals to avoid weight variation issues. If weight variation issue is not resolved after making all adjustments then must replace the fill cam because it may hinder the punch movement.
If there is any roughness or groves on the fill cam then must replace it with a new one.
Also Read