3447
As additive manufacturing ( AM ) advances rapidly towards new materials and applications , it is vital to understand the performance limits of AM technologies and to overcome these limits via improved machine design and process integration .
 As, additive manufacturing, AM, materials, performance limits, AM technologies, limits, machine, design, process
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:
 As, additive manufacturing, AM, materials, performance limits, AM technologies, limits, machine, design, process