Tabletting machines product shapes

Tabletting machines, 356 Manestv. 356,358 product shapes, 362 Sharpies, 356,358...

For accurately shaped compacts with extreme demands on tolerance only the confined die approach of pressure agglomeration is applicable. Such requirements exist, for example, in the pharmaceutical industry where tabletting machines are used to carry out the task. None of the growth agglomeration methods can yield products with these specifications. 

Shape is often also an important characteristic. In many cases spherical products of size enlargement are desired. This approximate shape can be obtained with all growth agglomeration methods. On the other hand, unless extremely accurate feed control can be established in some tabletting machines, spherical products cannot be produced with pressure agglomeration equipment. The nearest approximation would be lens- or almond-shaped compacts. 

The reciprocating movement of the piston(s) and the relatively small volume of the die cavity severely restrict the capacity of this type of equipment even if modern, multistation, rotary tabletting presses are considered. With the production of larger pieces in, for example, hydraulic presses or roller briquetting machines, the accuracy in weight, shape, and dimensions is no longer obtained. 

A blister pack or strip is a container with a foil that is shaped so that it can contain separate dosages [26]. An aluminium lidding foil closes the form foil. Blisters are mostly used to package tablets or capsules. For blister packs a form foil of PVC or laminate of PVC/PVDC (polyvinylidene chloride) is used. The form foil is warmed in a blister machine and a mold station makes round or capsule-Uke pockets with compressed air. PVC is permeable to water vapour and therefore not suitable for tablets or capsules that are moisture sensitive. To package such products the PVC form foil should include an outside layer of PVDC. PVDC permeates less water vapour. Dependent on product sensitivity to moisture, different PVDC-thicknesses can be chosen. When complete resistance to water vapour is necessary a form foil that consists of a formable aluminium laminate (consisting of polyamide, soft aluminium and PVC) has to be used. 

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