As part of the UNESCO World Heritage Site of Angkor, Cambodia, a bronze foundry site has been unearthed immediately north of the Royal Palace, within the vast urban area of Angkor Thom. Unique in Southeast Asia, the royal foundry was active during at least the 11th century CE. Since 2016, the research project LANGAU, run jointly by the APSARA National Authority and the EFEO, has been handling both excavation and analytical campaigns at the site. Two main objectives are targeted: first, to inventory and characterise the metallurgical know-hows mastered by royal founders, with a special focus on lost-wax casting; second, to define the organisation of a specialised metal craft dedicated to royal power. The present paper aims to report on specific on-site workflows associated with the chaîne opératoire of copper-based metallurgy, from the transformation of raw materials to the operation of casting. The archaeological and scientific investigations focused on two different excavated materials, with complementary uses: on one hand, a series of in-situ metallurgical structures identified as foundry furnaces, together with isolated related artefacts such as wall furnace, tuyeres, and iron supports; on the other hand, a large and representative assemblage of crucibles, mostly fragmentary. Our methodology included inventory, photography, photogrammetry, sieving, visual and microscopic examination. Collaborations with international laboratories were also developed for petrographic and elemental analysis. Two main types of furnaces, including forced-air furnaces with bellows and tuyeres, related to specific size and shapes of crucibles were identified. This established for the first time furnace and crucible typologies associated with Angkorian copper-based metallurgy. This allowed to appraisal of a series of corresponding metallurgical operations, that is copper refining, alloy preparation and casting, and to document distinct technological choices.