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Melt flow plays a critical role in laser metal additive manufacturing , yet the melt flow behavior within the melt pool has never been explicitly presented .
 concept or principle: Melt flow; manufacturing process: laser metal additive manufacturing; concept or principle: melt flow; material: melt pool
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: Melt flow, laser metal additive manufacturing, melt flow, melt pool 
Answer:
 concept or principle: Melt flow; manufacturing process: laser metal additive manufacturing; concept or principle: melt flow; material: melt pool