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This paper presented a 3D-printing system that integrated fused filament fabrication ( FFF ) and laser-based powder bed fusion ( PBF ) to produce hybrid metal and polymer components .
 3D-printing, fused filament fabrication, FFF, powder bed fusion, PBF, metal, polymer, components
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:
 3D-printing, fused filament fabrication, FFF, powder bed fusion, PBF, metal, polymer, components