Da Italiano a Inglese Altro Produzione manifatturiera, industriale shoe manufacturing

talking about personnel required for the development of a new shoe production technology - it's a list of various types of people, no explanation other than this :

"tre operai addetti a prove tecniche e prototipazione per taglio, giunteria, fondo"

It looks to me like some sort of assembly process. On the internet I have found various terms such as splicing, lining and skive-binding supposedly equivalent to giunteria but none of them looks right to me. Does anyone here have first-hand knowledge of the footwear industry and its manufacturing processes?