AWC is an auto-weight controller which regulates & controls the weight of tablets automatically during the tablet compression process.
Working Principle
AWC works on the principle of monitoring the compression force through a load cell by adjusting the filling of the die cavity according to the applied force & rejecting the over-weight or under-weight tablets.
Explanation
The load cell converts the mechanical force into an electronic signal to display the value of applied pressure or force.
AWC load cells are installed at the main compression rollers of the machine.
AWC adjusts weight according to the applied force, meaning for a standard weight, we have a specific value of force, and when this force deviates from the set value, it means the filling of the die cavity is altered, so a signal is sent to the dosing cam to increase or decrease the filling depth.
When the value of applied force is increased, it means that more powders or granules are filled in the die cavities, due to which the weight is increased, and ultimately the force is increased, so the filling depth is decreased by sending a signal to the servo motor of the dosing cam & vice versa.
Settings of AWC
To set the AWC for a new product, we will have to set the values for the auto weight controller to work.
Suppose our tablet’s weight is 200 mg, and we have an upper and lower weight range of 190 mg to 210 mg, respectively.
We will find out the value of the force applied for the above weight values by manual mode.
First of all, we will set the tablet weight at 200 mg & will check how much force is applied to compress the tablet at a weight of 200 mg, suppose it is 10 KN.
Now we will check the value of force for the upper weight limit, which is 210 mg and suppose it is 12 KN.
Now we will check the value of force for the lower weight limit, which is 190 mg, and suppose it is 8 KN.
Now we will go to the auto settings and will put these values for AWC to work. For entry, sometimes the value of variation is asked in percentage, so it will be ±20 %.
The auto weight controller will follow these values of force and maintain the weight of tablets near the standard weight and within the defined limits during the compression process. Whenever the applied force is increased from the value set for the upper limit, the signal is sent to the servo motor of the dosing cam to reduce the filling of the die cavity, and when the value of pressure or force is lower than the 8 KN, the filling depth of the die cavities is increased to increase the weight.
AWC auto rejection
All the tablets are rejected through an auto-rejection system which has a weight beyond the defined limits.
Meaning when the force value goes below 8KN, the tablets will be rejected through the rejection chute, and AWC will adjust the weight for upcoming tablets and vice versa.
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