– A 6,000-year-old amulet discovered in Pakistan offers proof of ancient high-tech knowledge. Our ancestors were familiar with lost-wax casting, a method used for making duplicate metal objects.
This technique is still used by NASA.
The amulet was found in 19774 at Neolithic village of Mehragarh, Pakistan. A technique known as ‘photoluminescence imaging’ has now helped experts to determine how the artifact was produced. The process involves shining a light on the artifact and then measure the amount of light that bounces back.
Scientists from Ipanema, a European center for studying archaeological materials have concluded that the amulet was cast as a single piece, leading the researchers to conclude that it was made used a process known as lost-wax casting. According to the study published in Nature, “a visual inspection indicates that its ‘spoked wheel’ shape consists of six small rods lying on a ring of 20 mm diameter.
At the centre of the wheel, the spokes were clearly pressed on each other until a junction was obtained by superposition; the base of each spoke was attached to the support ring using the same technique. Both the spokes and the support ring are circular in section.
Only a wax-type material, that is, easily malleable and fusible, could have been used to build the corresponding models. This wheel-shaped amulet cannot result from casting in a permanent mould: this shape could not have been withdrawn without breaking the mould, as no plane intercepts jointly the equatorial symmetry planes of the support ring and of the spokes without inducing an undercut. The artefact was therefore cast using a lost-wax process.”
The artifact has been identified as the oldest known object made by lost-wax casting and providing a better understanding of this fundamental invention.
The ancient object is also another good example showing our ancestors possessed advanced knowledge in a number of areas.
In modern times, we use lost-cost waxing to produce highly complex designs.
The technique has been used to create numerous components used on the International Space Station and the Curiosity Mars rover, as well as NASA’s now-defunct space shuttle.
The process was also used to create parts of the Messenger spacecraft, which orbited Mercury between 2011 and 2015.
‘It is also today the highest precision metal forming technique— under the name ‘investment casting’—in aerospace, aeronautics and biomedicine, for high-performance alloys from steel to titanium,’ researchers said.