1493
Also known as Thermojet , some systems can produce wax models in jetting tiny droplets of melted liquid material which cool and harden on impact to form the solid object .
 material: as; material: wax; manufacturing process: jetting; concept or principle: droplets; material: melted liquid material; concept or principle: harden; concept or principle: impact
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: as; material: wax; manufacturing process: jetting; concept or principle: droplets; material: melted liquid material; concept or principle: harden; concept or principle: impact