(111d) Powder Flow: the 4m Business and Systems Approach

Professor Scarlett initiated and promoted the 4M business for particle technology for years. The four M's consist of making, measuring, modeling, and manipulating. Measuring and modeling are tools to design and control products and processes, which we want to make and manipulate. To be able to use the 4M business properly, a systems approach needs to be used. Every system has its own time and length scale. From bottom up we can for example recognize atoms, molecules, particles, powders, process equipment, processes, and the environment. Every system builds up the next, each with its distinct time and length scale. In this paper the 4M business and systems approach as taught by professor Scarlett are explained and their applicability to powder flow is discussed. It will be shown that the four M's are largely interconnected and are more valuable used in conjunction. In industry the focus is on making products or equipment to handle these products. We want to manipulate these products and processes to optimize them. To do this we can measure and model. But what comes first? Chicken or egg, measuring or modeling? For reliable data a good understanding of the measuring equipment is eminent. None of the existing powder testers are perfect, so it is important to know what the strong and weak points of different testers are. Modeling can be used to find and explain the artifacts of existing testers. But for the models we need measurements. Models should be built upon first principles that contain parameters that have to be measured. The 4M approach will not work well by itself. It has to be implemented together with the systems approach, which connects different length scales, since every length scale feeds the one above it. Currently most of the powder flow measurements are performed with powder shear testers. Using the systems approach one has to start from the bottom. What is the material the particles consist of? What is the crystalline structure? What is the particle size distribution? What are the inter-particle forces? All this information is used to model a particle ensemble scale using Discrete Element Modeling. The number of particles that is simulated does not have to be very big, just enough to feed the next scale which is a Finite Element Model. This Finite Element Model simulates a powder as a continuum in e.g. process equipment. Depending on the problem extra length scales, between those named, might have to be investigated or length scales can be skipped. The power of the approach is the capability to manipulate the lower scales to optimize the scale that is of interest, in this case the powder flow scale. So the question what comes first, measuring or modeling, is a non-question. Measuring and modeling have to go hand in hand and across the different length scales. A better model enables the development of better measurements, and better measurements will aid to better models. Using the 4M and systems approaches, both products and processes can be designed reliably and in a cost effective way.