Drug Sheet Embossing for Folding Zones Without Sheet Breakage
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Solution Overview
Problem
Existing methods for manufacturing reconstituted drug sheets, such as tobacco sheets, face issues with overextension, non-uniform thickness, and sheet breakage during processing, leading to undesirable fly-out effects and reduced material integrity, which affect the quality and usability of drug delivery devices.
Innovation Solution
A method and system using embossing rollers with patrix-matrix features to create folding and stiffening zones on reconstituted drug sheets, ensuring consistent contact and alignment of embossing structures to prevent overextension, enhance sheet integrity, and facilitate folding into rods for drug delivery products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If crimping is used to form the drug sheet, then the sheet can be folded into a rod, but overextension occurs causing fly-out effect and sheet breakage
Solution Approach 1:
The embossing roller divides the sheet into distinct zones: compression zones with embossed structures for stiffening, and folding enabling zones without embossing for flexibility. This segmentation allows different parts of the sheet to have different mechanical properties, enabling folding without overextension.
Solution Approach 2:
The embossed structures are applied locally to specific regions of the sheet rather than uniformly across the entire sheet. The folding enabling zones maintain the original sheet quality and flexibility, while compression zones gain enhanced stiffness through embossing.
2Strength
If embossing is applied to enhance stiffness, then the rod stiffness is improved, but sheet thickness uniformity may be compromised
Solution Approach 1:
The embossing is applied partially only to compression zones rather than the entire sheet. The embossed structures provide enhanced stiffness where needed while leaving folding zones untouched to maintain uniform thickness and flexibility.
Solution Approach 2:
The sheet is segmented into compression zones with embossed structures and folding enabling zones without embossing. This ensures that stiffness enhancement is localized to areas where structural support is needed, while folding areas maintain original thickness uniformity.
3Stress or pressure
If conventional embossing is used, then material can be compressed, but overextension causes fly-out effect and material loss
Solution Approach 1:
The compression is segmented into discrete embossed structures rather than continuous compression. This localized compression applies force only where needed to create stiffening zones, preventing overextension and material fly-out in folding zones.
Solution Approach 2:
Compression force is applied locally through embossed structures in compression zones rather than uniformly across the sheet. This prevents overextension in folding enabling zones, eliminating the fly-out effect and associated material loss.
Data Source
Figure 1
Figure 2(A)~2(B)
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AI summary
A system for embossing a reconstituted drug sheet of at least a drug embedded in a binder, having a determined sheet thickness with a set of embossing rollers in view of obtaining a pre-rod drug sheet with at least a folding enabling zone and at least a stiffening zone, each extending as a corresponding stripe on the pre-rod drug sheet in a feed direction through the set of embossing rollers, and in view of preserving an integrity of the pre-rod drug sheet. The system comprises an embossing device with the set of embossing rollers comprising at least a first and a second embossing roller separated by a nip, and configured to receive the reconstituted drug sheet in the feed direction into the nip, patrix-matrix embossing features of positive and negative projections, on the first and the second embossing rollers, whereby each of the patrix and matrix embossing features on the first embossing roller has a corresponding congruent counterpart on the second embossing roller, producing the nip to have a substantially constant value; each of the patrix and matrix embossing features on the first embossing roller and on the second embossing roller has a structure profile in which any curvature radius has a minimum value of 40 µm, and any profile depth or profile height is smaller than twice the determined sheet thickness, thereby enabling the patrix and matrix embossing features on the first embossing roller and on the second embossing roller to consistently and gaplessly be in contact with both sides of the reconstituted drug sheet in the nip. Further, the at least one of the folding enabling zone and the stiffening zone comprises respectively folding enabling embossing features and stiffening embossing features as patrix-matrix embossing features, aligned on the first and second embossing roller in a radial manner configured to emboss the corresponding stripe on the pre-rod drug sheet.