1350
The origin of the WAAM process can be traced back to the 1925s when Baker proposed to use an electric arc as the heat source with filler wires as feedstock materials to deposit metal ornaments .
 manufacturing process: WAAM; concept or principle: process; material: be; process parameter: electric arc; material: as; concept or principle: heat source; material: as; concept or principle: materials; material: metal
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: WAAM; concept or principle: process; material: be; process parameter: electric arc; material: as; concept or principle: heat source; material: as; concept or principle: materials; material: metal