Issue link: https://www.e-digitaleditions.com/i/1000772
36 July 2018 Tablets & Capsules handling. An ultrasonic cleaner uses high-frequency pressure waves to agitate a liquid (typically cleaning solution or water) and cause cavitation, which creates tiny bubbles that loosen and remove debris from the tool surface. When used properly, ultrasonic cleaning is highly effective for removing traces of product and contami- nants, as shown in Figure 1. The ultrasonic waves pene- trate all tooling surfaces—including hard-to-clean areas such as key slots (not shown), cups, and die bores—and cause debris such as oil, grease, and biological residue to break up and disperse. However, when using an ultra- sonic wash unit, it's critical to ensure that the tools are rinsed and dried thoroughly, because any cleaning solu- tion residue or water left on the tool can corrode or dis- color the surface. The benefits of ultrasonic cleaning include: More effective cleaning. Ultrasonic cleaners remove even tightly adhered material from tool surfaces and are more effective and thorough than manual scrubbing, which can be ineffective on heavily soiled tooling and can dam- age delicate tool surfaces. Reduced cost. Not only does ultrasonic cleaning save labor costs, it also saves time. A typical ultrasonic clean- ing cycle for moderately soiled tools can last less than 15 minutes and requires little supervision, which frees up staff for other tasks. The most important way ultrasonic cleaning can reduce costs, however, is by preventing the tool wear and damage often caused by manual cleaning. Reduced environmental impact. Ultrasonic cleaning offers multiple environmental benefits compared to manual cleaning. Newer ultrasonic cleaners require much less energy and are more efficient to operate than older mod- els, and the machines require less water per tool than manual cleaning. Also, the FDA-compliant ultrasonic cleaning solution is environmentally friendly and non-ozone-depleting. Validated cleaning process. Most pharmaceutical compa- nies operate under very strict regulations and audit pro- cedures requiring that all product contamination is removed from all tablet press components, including tooling. Ultrasonic cleaning can allow a company to val- idate the process by swabbing the clean tools and verify- ing that, when the ultrasonic cleaning steps are followed, the tooling is free of contaminants and the process is repeatable. Polishing. Over time, tooling loses its luster and can develop nicks, scratches, and a wear pattern commonly called a J-hook, in which excessive wear around the perimeter of the punch cup creates a thin, sharp edge that curls inward. These imperfections can cause tablet defects such as capping, in which the top or bottom por- tion of the finished tablet separates from the tablet body; lamination, in which the finished tablet separates in hor- izontal layers; sticking, in which a portion of the com- pressed formulation adheres to the punch surface and breaks away from the tablet; and picking, which is simi- lar to sticking but occurs within the letters, logos, or designs embossed on the punch cup surface. Often, companies will replace tooling when these tablet defects damage mating press components, including the punch guides, keyways, cams, and pressure rollers. You can ensure proper lubrication at startup by simply applying a food-grade barrel lubricant to the punch bar- rel and a food-grade grease to the punch head prior to tablet press setup and operation. Cleaning. Dirty tools can also cause binding during operation. Keeping tools clean decreases the chance of premature tool wear and increases the effectiveness of lubrication, allowing the machine to run more efficiently and produce more tablets. An ideal cleaning procedure is one that consistently cleans the tools but minimizes handling to reduce the potential for damage. Ultrasonic cleaning with an auto- matic dryer is optimal because it increases the tooling's exposure to the cleaning solution and requires minimal Photo 1: Ultrasonic cleaning is a quick, easy, and safe method for thoroughly cleaning your punches and dies. Figure 1 Typical tablet punch a. Before ultrasonic cleaning b. After ultrasonic cleaning Head Barrel Tip Back angle Head flat Cup