808
It offers significant improvement in mechanical properties compared to discontinuous fibers , however , there is still no robust and standard paradigm developed for 3D printing of continuous fiber composites .
 concept or principle: mechanical properties; material: fibers; concept or principle: standard; manufacturing process: 3D printing; material: continuous fiber composites
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: 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:
 concept or principle: mechanical properties; material: fibers; concept or principle: standard; manufacturing process: 3D printing; material: continuous fiber composites