Tabletting process is generalized as four courses: feeding, flatting, tabletting, and ejecting. Any one course is so important to affect the quality of the tablets. But in the process of tablet manufacturing, we are often encountered with many problems of this kind or that kind. In this article, we would discuss the problem that many customers are fed up with, why the materials being fed into dies are insufficient, or why the weight of tablets is shorter than expected.
Obviously, this problem is related to the first tabletting course—feeding. No matter for the single punch tablet press or rotary tablet compression machines, if we could improve feeding condition, then we could get tablets of right weight. To solve the problem, we should figure out the possible causes first.
The first and the foremost cause can be the unqualified materials with poor fluidity.
Generally speaking, there is a certain formula to make tablet materials, active ingredients, excipients and other ingredients. And this formula directly influences the fluidity of the materials. Poor fluidity is always performed as the materials could not flow down steadily, stopping at a certain area. The solution is to make a comprehensive and qualified formula before applied in production.
If the size of particles are not uniform, the fluidity of material is also poor. Too coarse of the particles may be heaped up and blocked at the feeder inlet, whereas too fine may affect its gravity. Anyway, the materials could not gravitate themselves into the middle die cavity as a result of coarse or fine performance. Therefore, make sure that the materials applied are in uniform size, neither too coarse nor too fine.
The materials may get damp due to the moist in the air. Damp particles will be condensed into pieces that may block the inlet of die cavity, or adhere to the inside wall of feeder, clogging the channel of particles. So we have to store the materials at dry place, prevent them from damp and binding.
The second cause is the matter of bucket feeder.
This cause is only applicable for single punch tablet press like TDP-0, TDP-5. The rotary tablet press are equipped with fixed Tsukigata feeder, and some high speed rotary tablet press are configured with forced feeding system, both of which have good and strict control of the filling amount into die cavity.
On single punch pill press, the feeding course should be completed with lift pole’s up and down, lift cam’s rolling, bucket feeder’s feeding and scrapping. If the bucket feeder moves so fast that rush to finish filling, the consequence must occur that filling amount into the die cavity is less than expectation. In such case, the operator should adjust all the relevant components to ensure every part could exert its full function.