8561
Increasing void size in printed objects through FFF negatively affects strength Novel method of FFF proposed to reduce the void size Novel method reduces crosB-sectional void surface area by 18.0 % Novel method improves density by 6.5 % per mm increase in nozzle size Novel method improves max .
 void, FFF, strength, FFF, void, void, surface area, density, mm, nozzle
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:
 void, FFF, strength, FFF, void, void, surface area, density, mm, nozzle