9109
Counterintuitively , specimens with 0° infill direction were consistently the worst performing due to the tangency voids and poor edge surface finish resulting from the toolpath .
 infill, voids, surface finish, toolpath
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:
 infill, voids, surface finish, toolpath