Multi-layer Tablet Cavity Formation via Segmented Punch
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Solution Overview
Problem
Existing multilayer tablets with cavities face issues of density heterogeneities, mechanical strength, and disintegration problems due to complex production methods and density variations, which affect their functional and mechanical properties.
Innovation Solution
A rotary press device with a lower punch having a longitudinal cavity and a central rod coupled via a resilient link allows for the formation of compacted multilayer tablets with a through cavity, enabling homogeneous density distribution and improved mechanical strength by controlling the central rod's movement during the compaction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If compaction by stamping is used to form a cavity in multilayer tablets, then a cavity can be formed to receive inserts, but density heterogeneities are created within the tablet causing different disintegration and solubilisation profiles
Solution Approach 1:
The lower punch is segmented into a stationary outer portion and a movable central rod portion. This segmentation allows the central rod to be independently controlled during compaction, enabling it to retract and advance at different stages to form a cavity while maintaining uniform density throughout the tablet matrix.
Solution Approach 2:
The central rod is made movable relative to the lower punch through a resilient link mechanism, transforming it from a static structure to a dynamic one. This allows the central rod to retract during powder filling and advance during compaction, creating a cavity without compromising the overall density homogeneity of the tablet.
2Manufacturing precision
If independent controlling of different parts forming lower and upper punches is used to form ring-shaped layers, then relatively homogeneous mechanical properties are achieved, but the production method becomes complex to implement
Solution Approach 1:
The invention merges the functions of the lower punch and central rod into a single integrated lower punch assembly. The central rod is coupled to the lower punch through a resilient link, combining what would otherwise be independently controlled components into one unified mechanism, thereby simplifying the control system while maintaining homogeneous mechanical properties.
Solution Approach 2:
The lower punch serves multiple functions: it provides the stationary support structure, houses the resilient link mechanism, and integrates the central rod for cavity formation. This multi-functionality eliminates the need for separate control mechanisms for each component, reducing overall system complexity.
3Shape
If a fixed central element is used during the entire compaction cycle, then tablets with cavity can be formed, but the functional properties in terms of disintegration remain to be improved
Solution Approach 1:
The central rod is transformed from a fixed element to a dynamic one that can retract and advance. During powder filling, it retracts to allow complete cavity formation. During compaction, it advances to create the cavity wall. This dynamic behavior ensures proper cavity formation while maintaining optimal density for controlled disintegration.
Solution Approach 2:
The resilient link is pre-loaded to hold the central rod in a retracted position during powder filling, ensuring the cavity space is fully available. This preliminary positioning action allows for better powder distribution and cavity formation, which subsequently improves disintegration properties.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in tablets with enhanced mechanical and functional properties, including improved disintegration times and homogeneous density, facilitating easier production and handling while maintaining complex designs.
Implementation Method 1
a resilient link to hold, in a rest position, the central rod in a deployed position in which the central rod projects with respect to an active surface of the lower punch
Data Source
AI summary
The invention relates to a press device for manufacturing compacted tablets from at least one mixture in powder form, comprising at least one compaction assembly comprising a lower punch (3) and an upper punch (4) each having an active compaction surface and placed on either side of a die, in which the lower punch has a longitudinal recess open on the side of the die, inside of which is mounted a central rod which is translatably mobile relative to the lower punch, characterized in that the central rod is coupled to the lower punch by means of a resilient link provided so as to hold, in an inoperative position, the central rod in a maximum deployed position in which the central rod protrudes relative to the active surface of the lower punch. The invention also relates to a specific compaction method and to a multi-layer compacted tablet with a recess.