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The most common method for Additive Manufacturing ( AM ) of polymers is melt extrusion , which normally requires several pre-processing steps to compound and extrude filament feedstock , resulting in an overall long melt residency time .
 manufacturing process: Additive Manufacturing; manufacturing process: AM; material: polymers; manufacturing process: melt extrusion; manufacturing process: extrude; material: feedstock; concept or principle: melt
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: Additive Manufacturing, AM, polymers, melt extrusion, extrude, feedstock, melt 
Answer:
 manufacturing process: Additive Manufacturing; manufacturing process: AM; material: polymers; manufacturing process: melt extrusion; manufacturing process: extrude; material: feedstock; concept or principle: melt