1617
17- 4 stainless steel were first produced using direct metal laser sintering system in an argon atmosphere with spherical size of approximately 15 45 micro-meter in diameter .
 material: stainless steel; machine or equipment: direct metal laser sintering system; process parameter: argon atmosphere; concept or principle: spherical; concept or principle: diameter
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:
 material: stainless steel; machine or equipment: direct metal laser sintering system; process parameter: argon atmosphere; concept or principle: spherical; concept or principle: diameter