4791
The presence of δ-ferrite in 316L stainless steel powder reused several times contributes to structural defect formation in selective laser melted parts built using the pin support structure .
 material: 316L stainless steel powder; concept or principle: structural defect; manufacturing process: selective laser melted; engineering feature: support structure
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: 316L stainless steel powder, structural defect, selective laser melted, support structure 
Answer:
 material: 316L stainless steel powder; concept or principle: structural defect; manufacturing process: selective laser melted; engineering feature: support structure