Experiments
Basic Geometry Tests
To find appropriate heat and speed settings for extrusion, we conducted over one hundred iterations listed in reverse chronology.
- Horizontal Circle There is no vertical component in this extrusion. It is used to observe any dragging of the extruded geometry away from the intended path. This test helps reduce the relative dip in extrusion from the initial starting point.
- Vertical Arc Generation This vertical arc geometry determines lateral sag.
- Vertical Extrusion Test This preliminary test determines the consistency of the extrusion in one dimension. It is conducted vertically so that gravity adds minimal distortion along the extrusion path.
Causes of Failures
- Excessive heat If the speed of extrusion is too high relative to the material feed rate, the extrusion tapers. If the speed of the carriage is too high, the extruded material may collapse as it does not cool down quickly enough.
- Excessive speed If the speed of extrusion is high relative to the feed rate of the material, you can achieve thin extrusions. If the speed of the carriage is too high, the extruded material may not cool instantly and collapse.
- Low Flame For this test, a mini Butane torch was used. The rated heat of the flame generated by this torch is 1370ºC, too low to fully liquify the glass. Hence, the heat generated is barely enough to bend the glass rod. The following footage was sped up by 100X.
- Re-Heating and Deviation Without the use of vacuum to evacuate excess hot air, the flame reheats previously extruded geometry. This causes a deviation from intended extrusion path.
- Glass suction If the vacuum hose is placed too close the semi-liquid glass, it may get sucked in. Maintaining an appropriate distance and angle is crucial to appropriately divert excess hot air.
Handheld Tests
Initial extrusions carried out by hand to better understand the material properties and behaviour of soft (Effetre/Moretti) glass.