2403
A major factor limiting the adoption of powder-bed-fusion additive manufacturing for production of parts is the control of build process defects and the effect these have upon the certification of parts for structural applications .
 additive manufacturing, production, build, defects
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 additive manufacturing, production, build, defects