188
Thus , it is quite difficult to obtained fully consolidated parts , without defects , using AM methods that produced directly sintered bodies .
 concept or principle: defects; manufacturing process: AM; manufacturing process: directly sintered bodies
Please list all entity words in the text that fit the category.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} 
Answer:
 concept or principle: defects; manufacturing process: AM; manufacturing process: directly sintered bodies