4600
Mechanical properties of the structures were investigated in order to estimate the quality of the 3D printed parts in electronics ’ industry .
 concept or principle: Mechanical properties; concept or principle: quality; application: 3D printed parts; concept or principle: electronics; application: industry
Given options, please tell me the categories of all the listed entity words.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} 
 Entities: Mechanical properties, quality, 3D printed parts, electronics, industry 
Answer:
 concept or principle: Mechanical properties; concept or principle: quality; application: 3D printed parts; concept or principle: electronics; application: industry