♦Open hearth furnaces have high energy consumpiton rate since prone to heat loss compared to induction type furnaces. Coils either be locate on outer or inner part of the furnace. Kanthal(ferric-chrome-aluminum) alloy type coils could be used in inner type coils. They have lower heat output since those are resistance type coils so temperature range is varying 700-900 celsius degree. Therefore, this type crucibles only be used for specific purposes like art products. Different coil thickness will be resulted with altering temperature rates in hearth. Outer type coils are can be specified for various directions (R,T,S) to achieve desired heat distribution. Those coils are activating EMF to create enough heat for melting.
♦Three general types of glass melting furnaces are commonly used which are cross-fired, back fired and cross-fired float furnaces.
♦Indirect AM requires RT, binders, and post-processes like drying, sintering, and debinding. DIW has a lower viscosity advantage, so it enables a wider production range among glass types. Silica fumes are used, and TiO2 and rare-earth oxide dopants would increase refractivity. The incidence of cracking is lower, but particles could cluster. A sol-gel approach for DIW can overcome the clustering problem. DIW is limited to simple and 2D-shaped production.
♦SiO2 particles are merged with resin monomers, which are curable with UV and make complex designs achievable.
♦Suspended nanoparticles are used with the resin mixture borosilicate and phosphateslicate glass, which can be produced without issute. Pore size is much lower compared to SLA.
♦TPP is allowing the production of micron-scaled products. Laser sources measuring 505nm or 1030nm are suitable. A smaller particle size requires better surface quality.