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12 Pharmaceutical Technology TRENDS IN MANUFACTURING 2022 eBOOK P h a r mTe c h . c o m Solid Dosage The first step in the process is to clean the tooling. Punches and dies should be completely clear of dirt, lubricants like oils and grease, and product contami- nation. Any residue left on the tooling can cause cross contamination between campaigns and also hide a multitude of problems such as cracks or chips. If the cleaning step is not completed effectively and residue remains, it will lead to tableting issues such as sticking. New product can stick to the old causing major problems for the next batches or new campaigns resulting in visually undesirable tablets and weight variation. Product left on the punch tips can also cause the punches to become overloaded by way of double compression and result in tip break- age and tablet press damage. Corrosion is another negative affect of incorrect or ineffectual cleaning practices. Some granule contains corrosive elements, and if these are left on tools for longer than is necessary, they will corrode the steel. The process of cleaning can be split into four prin- ciples: time, temperature, mechanism, and chem- istry. These work together to complete a cleaning cycle. Increasing the effectiveness of any of the prin- ciples (i.e., raising the temperature, or increasing the cleaning time) reduces the requirement for other processes, like the use of a stronger detergent. Ultra- sonic is the most effective method to ensure tooling is clean and free from contaminant and works to the four principles of cleaning thanks to its controlled mechanism (Figure 2). This means each inf luence can be controlled. For example, a shorter cleaning cycle time to improve production efficiency can be utilized, or a temperature that does not negatively affect the tooling can be used. This process has the benefit of being suitable for both coated and uncoated tooling and can produce excellent results in short cycle times. Inspecting the damage Following cleaning, the next step is to assess the tablet tooling. Assessing tooling can give an indi- cation of problems with the tablet press or with the tooling itself. For example, it can identify press setup issues that could cause problems during pro- duction, such as tip misalignment or die pocket wear. It also helps to find punch damage like tip breakage, cracks, and bruises. It is important to inspect all parts of the punch including the barrel, neck, head, and key if present. Also be aware of tip stem distortion if the tooling is used to produce small tablets. Due to the reduced dimensions, these designs are susceptible to bend- ing from over pressure. Corrosion can also be found during this step. This can be detected by the appearance of discol- oration, etching, or common red rust. There are many reasons for corrosion to form including un- suitable cleaning methods and the lack of corro- sion inhibitor to form an oxide film on the surface of the metal. It can also simply be caused through corrosive product being left on the tooling for too Figure 1. A program of consistent maintenance procedures should be followed to ensure punches and dies are ready for production. FIGURES ARE COURTESY OF I HOLL AND.