Lasers a boon for the manufacture of Thai ceremonial umbrellas

Found atop pagodas, in Buddhist ordination halls and in royal palaces, the tiered umbrella is one of Thailand’s oldest and most sacred ornamental symbols. It can take master craftsmen up to six months to make one of these ornamental pieces, also called chatras.

In the Laser Applications Journal, Researchers have demonstrated a technique for manufacturing seven-tier umbrellas using high-power lasers, dramatically reducing production time. Using carbon dioxide lasers, they were able to manufacture stainless steel umbrellas in a matter of days while preserving their intricate beauty.

“Currently, artisans who make multi-tiered umbrellas have become rare,” says author Pichet Limsuwan. “We hope to show a new way to contribute to the preservation of arts and culture in Thailand.”

The use of chatras dates back to the Dvaravati Kingdom, which ruled what is now modern Thailand 1,400 years ago. Royal chatras come in odd-numbered variations of five-, seven-, and nine-tiered umbrellas that correspond to princes, crown princes, and kings, respectively.

A year ago, Limsuwan set to work to better understand the customs surrounding chatras and how they are made. His first months of umbrella research involved studying primary historical documents written in Thai and then synthesizing his findings into a history written in English, a rare type of research for physicists.

Decorated with ornate brass and often featuring white silk lampshades edged with gold and precious stones, conical chatras are suspended above sacred places, each concentric level wider than those before it.

“A new king will not be able to sit on the throne under the nine-tiered umbrella until the coronation rites are completed,” Limsuwan said.

Lasers offer many advantages in manufacturing such finely detailed items, including narrow cuts, smooth edges and the ability to process complex shapes.

Brass, traditionally used for chatras, is however highly reflective and not well suited to laser cutting. To get around this problem, the team used stainless steel. To achieve the characteristic golden colour, they deposited titanium nitride onto the steel using electric arcs in vacuum chambers.

This approach reduces the six-month time it takes to make an umbrella to about 113 hours. While much of the process is automated, hand drawings can be easily incorporated using common laser manufacturing tools.

The group provides extensive technical details for anyone with the equipment to make umbrellas themselves, from vacuum and electrical settings to titanium nitride deposition to expected production times for each piece.

“Thailand is a country rich in arts and culture,” Limsuwan said. “The multi-tiered umbrellas are just one example of Thai arts, culture and religions. I think future projects will be related to other facets of Thai arts, culture and religions.”