How to choose a suitable pelletizing method for my materials?

The common pelletizing methods we can see are underwater pelletizing, die face pelletizing, strand pelletizing, and water-ring pelletizing. The underwater pelletizing is especially for materials with high viscosity, low MI, or difficulty to be shaped. The die face pelletizing can be used for PVC or materials that can’t contact with water. The strand pelletizing is suitable for most plastics; however, appearances of pellets are not very good and larger factory space is needed. As to the water-ring pelletizing, it is widely used, but it is not suitable for sticky, low-viscosity materials.