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In order to overcome these issues this study follows an open hardware approach , which uses an open source 3-D printer to both fabricate the slot die and then to functionalize a 3-D slot die printing system .
 source, 3-D, fabricate, die, 3-D, die
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, 3-D, fabricate, die, 3-D, die