2227
In order to achieve this goal , a first step is to prove the technical feasibility to recycle thermoplastic material intended for open-source 3D printing feedstock.The contribution of the present study is twofold : first , a general methodology to evaluate the recyclability of thermoplastics used as feedstock in open-source 3D printing machines is proposed .
 step, feasibility, thermoplastic material, open-source, 3D printing, methodology, recyclability, thermoplastics, as, open-source, 3D printing
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:
 step, feasibility, thermoplastic material, open-source, 3D printing, methodology, recyclability, thermoplastics, as, open-source, 3D printing