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The effective structural strength was 14–32 % of the strength of fully dense Ti-6Al-4V made by PBF and the ligament structural strength was 34–49 % of the strength of fully dense material .
 strength, strength, fully dense, PBF, strength, strength, fully dense
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:
 strength, strength, fully dense, PBF, strength, strength, fully dense