Abrasive Formulations
Formulations containing abrasive substances such as calcium salts, iron oxides, or certain herbal extracts can cause significant wear on punch tips and die walls. These abrasive particles act like micro-grit, eroding polished surfaces and shortening tooling life. For abrasive blends, high-wear-resistant steels such as D2 or powder metallurgy (PM) steels are recommended, complemented by hard coatings like Chromium Nitride (BS-CN) or Titanium Nitride (BS-TN). These coatings create a durable, low-friction surface that extends tooling service life.
Corrosive Formulations
Acidic, hygroscopic ingredients or moisture-rich excipients can corrode standard tool steels, especially during idle periods or prolonged production runs, causing surface pitting and contributing to sticking and poor tablet quality. Corrosion-resistant steels such as H13 or 440Care preferred for these formulations, often with protective hard chrome (BS-HC) or enhanced chrome (BS-EC) coatings. For highly aggressive environments, stainless-based alloys or carbide dies with anti-corrosive coatings may be necessary.
Sticky or Waxy Formulations
Formulations high in waxes, oils, or polymers frequently cause sticking and picking on punch tips and die walls, damaging engravings and creating residue buildup. Tooling for such sticky formulations requires a mirror-like polish and may benefit from non-stick coatings such as BS-EC or BS-CX, which lower surface energy to facilitate product release. Tablet shapes with rounded edges and shallow engraving designs also help minimize sticking.
High-Compression Formulations
Some formulations need higher compaction forces due to poor compressibility, including high-dose actives, certain herbal extracts, or blends with low binder content. These exert intense mechanical stress on tooling and risk tip breakage or punch head wear. Tools for high-compression applications should be manufactured from high-strength steels like S7 or A2, with precise heat treatment. Reinforced punch heads or carbide inserts may be employed to withstand heavy mechanical loads.
Reactive or Coated Formulations
Certain actives may chemically react with tooling surfaces during compression, while others are pre-coated with delicate films that risk scratching or deformation. Maintaining tool surface integrity and chemical compatibility is vital. Special coatings such as Titanium Nitride (BS-TN)and Chromium Nitride (BS-CN) offer chemical resistance and reduce surface energy, minimizing interaction with sensitive formulations.
Selecting appropriate tooling materials and coatings tailored to formulation types is critical for maximizing tooling life, enhancing tablet quality, and ensuring efficient production in pharmaceutical manufacturing.
