Powder Testing-Dealing with the Daily Challenges

摘要

Efficient,quality manufacture coupled with continued cost reductions remain high priorities in the powder processing industries.Process optimisation is helped by the ability to predict process behaviour,but the nature of powders often makes this reasonable expectation difficult to achieve.Powders are complex in that their rheological or flow properties can change greatly,to the detriment of efficient processing.This complexity stems from the fact that powders are a mixture of solids,liquids and gases (usually air).Individually,each of these constituents is well understood,but in combination they can be unpredictable and databases of the rheological properties of powders simply do not exist.Developing an understanding of the way that powders behave under different sets of conditions can hold the key to improved processing.Traditional approaches to characterising powder flowabi-lity often fail to provide sufficient information for the necessary optimisation of powder and process.In this article,some of the challenges facing the powder processor are explored and the use of a powder rheometer for the measurement of flowability is examined,with examples from pharmaceutical processing.