8151
The results clearly show that open source industrial FPF/FGF 3D printers have significant economic potential when used as a distributed recycling/manufacturing system using recyclable feed stocks in the green fab lab context .
 source, industrial, 3D printers, as, recyclable, feed
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:
 source, industrial, 3D printers, as, recyclable, feed