Nowadays, 3D printers can extrude a lot of different substances. Ranging from food to metals, the list is growing at an exponential rate. Now another unfamiliar addition has been made to that list: glass. While powdered glass and silica have already been extruded by 3D printers, this will be the first time molten glass is extruded. The idea credits for this belong to a team of researchers led by Neri Oxman of MIT’s Mediated Matter Group.
The process is first of its kind and is called Glass 3D Printing or G3DP for short. It extrudes optically transparent glass through a material extrusion 3D printer and updates the 4,500 year old glassmaking process to produce beautiful objects and ornaments.
There were a lot of challenges faced by the team as the glass requires to be cooled down in a controlled environment and temperature to avoid undesirable stresses which may result in spontaneous breakage of the glass in the future. The team used propane torches at first but this method was unfeasible and laborious. Thus, an annealing chamber was built at the bottom of the setup, into which the objects were printed and then cooled in a controlled environment.
The fused deposition modelling (FDM) is most common in 3D printing but its applications are quite limited as it cannot handle materials with high melting points. This gives the FDM some unwanted limitations. The G3DP, on the other hand, uses glass which has many durable and optical properties and is very cheap to produce, requiring only silica sand, soda ash and limestone as raw material.
The G3DP setup includes a kiln cartridge where molten glass beads are top loaded into a 1,800 watt furnace which retains the molten state of the glass between 1,040 and 1,165° C. This temperature range can be changed and maintained depending on the viscosity of the glass. This molten matter is then extruded through a 10mm diameter, 300 watt ceramic nozzle which is pre-heated at 1,000° C.
The size of the objects that this setup can produce is limited by the annealing chamber which is 250 x 250 x 300 mm at the moment. The chamber is equipped with a transparent ceramic windows to observe the building process, layer after layer. The applications are endless. Besides artful glass sculptures, this printer can be used in the future to produce lab equipment and parts for the aerospace industry. The details of this whole project are published in the 3D Printing and Additive Manufacturing journal.
The following video shows the G3DP setup in action.