7500
However , 3D printing carbohydrate glass in this way presents several unique challenges : 1 ) the material must resist degradation and crystallization during printing , 2 ) the glass must be hot enough to flow freely during extrusion and fuse to the printed construct , while cooling rapidly to retain its shape upon exiting the nozzle , 3 ) the extruder needs to apply high pressure , with rapid stop and start times and 4 ) the net force that acts on the filament during extrusion must be minimized so that the filament shape is predictable , i.e. , coincides with the path taken by the nozzle .
 manufacturing process: 3D printing; material: glass; material: material; concept or principle: degradation; concept or principle: crystallization; material: glass; material: be; concept or principle: flow freely; manufacturing process: extrusion; manufacturing process: fuse; concept or principle: printed construct; concept or principle: cooling rapidly; machine or equipment: nozzle; machine or equipment: extruder; concept or principle: pressure; concept or principle: force; material: filament; manufacturing process: extrusion; material: be; material: filament; concept or principle: predictable; machine or equipment: nozzle
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: 3D printing, glass, material, degradation, crystallization, glass, be, flow freely, extrusion, fuse, printed construct, cooling rapidly, nozzle, extruder, pressure, force, filament, extrusion, be, filament, predictable, nozzle 
Answer:
 manufacturing process: 3D printing; material: glass; material: material; concept or principle: degradation; concept or principle: crystallization; material: glass; material: be; concept or principle: flow freely; manufacturing process: extrusion; manufacturing process: fuse; concept or principle: printed construct; concept or principle: cooling rapidly; machine or equipment: nozzle; machine or equipment: extruder; concept or principle: pressure; concept or principle: force; material: filament; manufacturing process: extrusion; material: be; material: filament; concept or principle: predictable; machine or equipment: nozzle