1053
Additive manufacturing employing Gas Tungsten Arc ( GTA ) as the heat source is capable of fabricating fully dense metal components layer upon layer .
 manufacturing process: Additive manufacturing; concept or principle: Gas; concept or principle: Arc; material: as; concept or principle: heat source; manufacturing process: fabricating; material: metal; machine or equipment: components; process parameter: layer
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, Gas, Arc, as, heat source, fabricating, metal, components, layer 
Answer:
 manufacturing process: Additive manufacturing; concept or principle: Gas; concept or principle: Arc; material: as; concept or principle: heat source; manufacturing process: fabricating; material: metal; machine or equipment: components; process parameter: layer