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Electron beam melting is available but most systems use laser energy , normally in a sealed chamber , in an inert gas environment or a vacuum .
 manufacturing process: Electron beam melting; concept or principle: laser energy; concept or principle: inert gas
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:
 manufacturing process: Electron beam melting; concept or principle: laser energy; concept or principle: inert gas