Highest hygiene: stainless steel, rust-free, for tray handling systems

In integrated plant concepts for tablet manufacturing, product-contact components made of stainless steel corrosion-resistant provide the necessary product safety across processes. © L.B. Bohle

Granulation systems with stainless steel components ensure efficient granulation. © L.B. Bohle

The use of stainless steel in tablet manufacturing equipment significantly contributes to the quality, safety, and cost-effectiveness of the products. © L.B. Bohle

Stainless steel, due to its corrosion resistance and good processing properties, is a standard material for numerous components in tablet manufacturing equipment. © WZV/ERWEKA

High-quality stainless steel, rust-free, meets the strictest hygienic requirements through its smooth, abrasion-resistant, and easy-to-clean surface. © L.B. Bohle

In tablet manufacturing systems, components made of stainless steel – like this measuring machine – provide reliable protection against emissions and cross-contamination. © FETTE Compacting

The use of stainless steel (stainless) in this fully automatic tablet hardness tester guarantees a hygienic production environment. © WZV/ERWEKA

For equipment enclosures, stainless steel is the guarantee of sustainably highest hygiene and reliable durability in 24/7 operation. © FETTE Compacting

For granulation systems, stainless steel (rust-free material) is the material of choice. © L.B. Bohle

Granulate flow tester with built-in stainless steel funnel and stainless steel outlet nozzles. © WZV/ERWEKA

When it comes to stainless steel tablet presses, product quality and process safety are the focus. © FETTE Compacting

Tablets are among the most widespread forms of medication, nutraceuticals, and dietary supplements. Easy to dose, convenient to transport, and to take with a sip of water whenever needed, they ensure precise release of active ingredients. Their production demands the highest standards: consistently high quality and compliance with all regulations for process and food safety must be balanced with resource-efficient, sustainable manufacturing and cost-effectiveness. Tablet presses, which can be flexibly used for batch and high-volume production, automate and control the complex process from powder to finished tablet. The heart of these production lines are tablet presses, as they significantly contribute to the quality, safety, and economic efficiency of the products. For all parts in contact with the product, high-quality stainless steel, corrosion-resistant, is mandatory.

Diverse types of tablets – single or multilayer, coat-core, effervescent, or lozenges – as well as various tablet shapes require tailored equipment concepts. The range of tablet presses extends from laboratory eccentric presses for initial feasibility studies, through R&D rotary presses, standard single and multi-station rotary presses, to high-performance double rotary presses. Fully integrated systems in enclosed design with containment features for highly active or toxic substances encompass the entire production process, from material feeding, dosing, granulation, to tableting and quality control, packaging into blisters or cans, as well as cleaning, retooling, and maintenance of all system components.

Fundamental components of every tablet press include hoppers, feed shoes, dies, and punches. Besides the active pharmaceutical ingredient, tablets usually contain additional excipients such as binders, lubricants, and flow regulators. A balanced interplay of these components is crucial for the flow properties of the material. Granulates have better flow characteristics compared to powders and can therefore be dosed more effectively. Various processes such as fluidized bed, vertical, high-shear, or double-screw granulation are used industrially to produce granulates for tablets. Batch granulators combine three process steps in one vessel: mixing, vertical or high-shear wet granulation, and drying.

Up to one million tablets per hour

The powder or granulate mixture is fed into the hopper, which distributes it into openings called dies, determining the later tablet shape, on a rotating die wheel. Die segments can replace the rotor to enable significantly more tablet stations at the same press size. In the dies, upper and lower punches compress the material with increasing force into the final tablet shape. Often, tablets are also marked with a break line and a logo here.

Sensors measure the pressing force and ensure consistent quality by monitoring weight, hardness, thickness, and breaking strength of each individual tablet. Some press models address the high load on tooling with heavy-duty profile heads to minimize wear. The finished tablet is pushed upward from the die by the lower punch and transported into a collection container or onto a conveyor belt by a shuttle. High-performance presses process all types of granulate and viscous products at high speed using changeable die discs. They can produce over a million single-layer tablets in various shapes or up to 500,000 multilayer tablets per hour.

Protection against emissions through containment features

Ensuring process safety also involves protecting people and the environment from emissions. Product changeovers require the press to be thoroughly cleaned beforehand to prevent cross-contamination. Increasing demands for active ingredient safety and process control are reflected in various containment features in tablet production. Modern tablet presses are designed with dust-tight basic equipment and operate under vacuum to prevent active ingredient escape. When processing highly active or toxic substances, a fully enclosed system with complete containment features is necessary. The five-stage containment pyramid from the International Society for Pharmaceutical Engineering (ISPE), known as the Occupational Exposure Band (OEB), is used to classify the hazard level of the substances used.

In practice, for products rated OEB 3 and above, fully automated tablet production from system filling to dust-minimized tablet discharge is considered the minimum standard. Glove boxes, leak-proof transfer systems, and efficient dry and wet cleaning technologies complement containment solutions. From OEB 4 onwards, Wash-in-Place (WIP) procedures significantly reduce the workload for machine operators during cleaning. For hazard class OEB 5, the highest safety requirements in production and personnel protection are ensured by a highly complex high-containment system for the entire plant: including a closed material handling system with fully enclosed, integrated production lines from automatic material feeding, tableting, in-process quality control, comprehensive dust emission control, air management, and Wash-in-Place technology.

For highly active active pharmaceutical ingredients, whose demand is rapidly increasing due to new therapies, such as in oncology, continuous direct compression in a closed system is considered a future-oriented solution.

Cross-process use of stainless steel

Given strict requirements for hygiene and purity of the production environment according to ISO standards or Good Manufacturing Practice (GMP), stainless steel is indispensable for all product-contact components in tablet production lines. High-quality stainless steel, such as grades 1.4404 and 1.4435, meets the strictest hygienic standards due to its smooth, wear-resistant, and easy-to-clean surface. The durable surface quality of this inert material withstands corrosive environments, high pressures, and temperatures over the long term. Particularly, austenitic stainless steel 1.4404 with 2 to 2.5 percent molybdenum content is a standard material for many components in integrated production lines due to its corrosion resistance and good processing properties.

Electropolished surfaces with defined roughness prevent particle adhesion, further increase corrosion resistance, and withstand mechanical stresses. Appropriately designed stainless steel components in tablet systems are fully WIP-compatible and can be cleaned repeatedly without residue. In integrated tablet manufacturing systems, product-contact components made of corrosion-resistant stainless steel provide the necessary process safety and reliable protection against emissions and cross-contamination across the entire process chain.

From IBC containers for raw material and product storage, to granulators, mixers, hoppers, dies, and punches, up to conveyor belts, sampling systems, waste disposal units with metal detectors, sorting and counting systems, high-quality stainless steel is standard practice. It is also used in dust extraction filters, air filters, cleaning systems, sensor and control housings, and plant enclosures, ensuring maximum hygiene and reliable durability in 24/7 operation.