Issue link: https://www.e-digitaleditions.com/i/723777
As times have changed, so have many of the variables that contribute to successful tablet compression. Pharmaceutical and nutraceutical preparations have improved and in many cases their potency has risen sig- nificantly. That fact, coupled with a regulatory climate that has—by necessity—become more stringent, have made any form of guesswork or operational "feel" out of place. The standard now: Precise, efficient manufacturing at high speed. Tablet press manufacturers have responded to the need for more speed and better efficiency with a variety of new features and upgraded processes. They center around three areas: changeover, operation, and maintenance. Changeover The importance of being able to thoroughly clean a tablet press after a campaign and quickly prepare it to run another cannot be overstated. Today's most advanced tablet presses are recipe-driven, meaning that once the parameters for successfully compressing a particular tablet are in the control system, operators don't have to re-enter data the next time they run that product. The result is a streamlined process with better product yield and less waste. Many manufacturers are opting to use "quick-change" kits, which assemble all the product-contact components used by the press during a campaign. These typically include items that are quick to remove and install, such as the product hopper, feeder, scrapers, take-off assembly, and re-circulation components. Quick-change kits allow operators to switch rapidly between products. They also allow you to clean the product-contact components from the previous campaign offline and prepare them for use in another quick-change kit. Removable turret assemblies are a big part of reducing changeover times, because they eliminate the most labor- intensive part of any changeover: Cleaning and setting up the punches and dies at each individual station. With a second turret cleaned, tooled, and ready for action, you can quickly and simply remove the dirty turret, clean the interior of the press, and start manufacturing. It makes a huge difference in how quickly companies can get their presses back into service for a new campaign. Everyone using a tablet press should stay in touch with their preferred vendors to learn what new features are available and whether they come only with a new press model or can be retrofit. Tablet press suppliers often improve the components on existing models and those improvements can have a big impact on your operation. Examples include components that optimize how the feeder operates and adjusts, paddle wheels of different shapes and styles, and seals that contain dust better and thus increase yields and reduce the time needed to pre- pare the press for a new campaign. Some tablet press options have revolutionized the con- cept of changeover. The tedious task of removing and rein- stalling the tooling—the single-most time-consuming part of changeovers—is a good example. That job can be made much faster and easier by eliminating individual dies in favor of robust segments that have the product cavities machined into them. Operation Assuming a powder or granulation flows well enough to reach the material hopper of a tablet press, the next sub- assembly it encounters is the feeder. It's difficult to overstate the importance of the force feeder to the operation of a modern press. It's the critical component for moving the product from the hopper and into the die cavities in the correct amount, often at high speed. That's why the top tablet press manufacturers offer not only operational improvements to feeders, but also enable you to adjust them much more easily than before. Another improvement pertains to monitoring the rela- tive standard deviation (RSD) of compression force as the tablet press operates. RSD correlates strongly with how consistently die cavities are filled. If the RSD is erratic, or high—i.e., in excess of around 3.5 to 4 percent—then the operator must adjust the feeder speed in order to stabilize or even improve the process. Today, that adjustment is sim- ple because most modern presses use feeders with drives that are independent of the machine's main motor. In fact, many presses enable you to change the rotational direction of the feeder paddles and/or change the paddles them- selves. Different paddle configurations, i.e., flat-faced spokes versus cylindrical ones, can have very different effects on different products. It is also critical for operators to understand that when it comes to compression force, it's possible to apply too much when seeking to hit the target tablet characteristics. It's understandable that operators would opt to apply more than enough force because many new presses can produce very high forces. But the maximum force the press can gen- erate is rarely, if ever, needed to achieve the target tablet hardness. In fact, applying too much force is counterpro- ductive: Instead of making better tablets, you'll damage the particles you're compressing, which could lead to softer, not harder, tablets. 14 September 2016 Tablets & Capsules Swapping fully tooled turrets reduces downtime because technicians don't have to set up the punches and dies at the machine.