- Efficient production starts with the design of the tablet.
- Round, flat tablets offer the greatest efficiency.
- Applications, active materials, and, increasingly the design as well, all call for more complex shapes.
The formula for tablets that can be pressed with the greatest efficiency is: round and flat, or lightly domed. Tablets of this shape can easily be filled, dosed, compressed and output. The simple design allows production to proceed at maximum rotation speed. In this way manufacturers can efficiently produce even large batches of tablets with constant hardness, strong edges and little tendency to adhesion.
Special shapes in tablet production
Special shapes are often chosen for the tablet design for marketing reasons: it is important for users to give their tablets unique features with a recognition value. For some active materials, the dosing also affects the shape. If, for example, the tablets are to be coated, shapes on the spectrum between domed and spherical are necessary. If the quantity of active material is large, a round tablet can be too large to swallow comfortably. An oval, or a narrower, oblong format is appropriate in these cases.
Indentations at the side, special figures or other special shapes often present a challenge to the production process. It is more difficult in these cases to ensure that the tablets are all of consistent hardness. This can result in differences in filling and in filling times. Indentations and engraving are the most complicated, in particular closed letters (such as A, B, O or R). This can lead to fracture or adhesion of the tablets. When necessary, islands and peninsulas are sunk into the tablet surface to counteract this.
Tuning design to technology
Early consultation with the tool manufacturer is helpful in bringing production and design into harmony. Solutions can be found in this way, even in difficult cases. Consider one example: an international pharmaceutical manufacturer wanted to develop a chewing gum, in tablet form, for large quantity production. In the first prototype, however, the chewing gum had an extremely complex engraving, which had a negative impact on the efficiency of the production process.
Through small changes in the engraving, Fette Compacting, working with the customer, was able to harmonize the design with the production process. It was then possible to manufacture long runs of the product on high-performance rotary presses. Fette Compacting was, moreover, able to impress the customer with the high quality of delicate logos and engravings of photos.
Tableting tools for different shapes
The tableting tool and the tablet press must cooperate optimally, whatever the tablet shape. In this way, users achieve long service lives at the same time as high yields and low levels of servicing work. The tableting tools from Fette Compacting are optimally matched to all the components of the high-performance rotary presses, and are designed for high performance as well as for low wear. The precise calculation of the pressing force using CAD-supported FEM (Finite Element Method) techniques ensures reliable use up to the loading limits of the punch material. This accurate method of calculation, matched to the press shape, is a standardized process, and a fundamental precondition for every product release.
Punch with application-oriented head shape
The FS punches from Fette Compacting are suitable for the varying production requirements that result from tablet design. They feature application-optimized head shapes, and are ideally designed for the high rotation speeds demanded by the market.
Thanks to its special head shape, the FS12 punch permits almost exactly the same compression dwell time as the EU19 punch. On top or this, as a result of its narrow shaft, more stations can be used, raising the yield by up to 40 percent.
The FS19 has an effective compression region about 30 percent longer than the EU19 punch. With the same output, this can be seen in a compression dwell time some 30 percent longer, which has a positive effect on the hardness of the tablet with pharmaceutical formulations.
The FS45 punch is designed for even higher compression forces, and a compression dwell time 30 percent longer than the EU45 punch. It has been possible to demonstrate this in practice in, for example, the production of laundry tablets.
This article originally has been published on "Prozesstechnik Online". Read the full article there.