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Residual deformations and internal stresses caused by the repeated layerwise melting of the metal powder and transient cooling of the solidified layers still presents a significant challenge to the profitability and quality of the process .
 concept or principle: Residual deformations; machanical property: internal stresses; manufacturing process: melting; material: metal powder; concept or principle: transient; manufacturing process: cooling; concept or principle: quality; concept or principle: process
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: Residual deformations; machanical property: internal stresses; manufacturing process: melting; material: metal powder; concept or principle: transient; manufacturing process: cooling; concept or principle: quality; concept or principle: process