Printing unit comprising two or more stereolithography machines and at least one data processing unit configured in such a way as to manage the functions of each one of said stereolithography machines for printing three-dimensional objects through a stereolithography process, wherein each one of said stereolithography machines comprises second coupling means for installing, as at least one consumable element, at least one vat suited to contain the material to be used for making said three-dimensional objects, said vat being provided with a univocal identification code, said printing unit being characterized in that it comprises a validation system of at least one vat, said validation system being provided with:
- said at least one data processing unit comprising reading means configured to read said univocal identification code of said vat and transceiver means configured in such a way as to transmit said univocal identification code to a remote server configured to communicate with said data processing unit through an Internet connection;
- said remote server comprising storage means having a predefined list of univocal identification codes, considered authentic and active, related to at least said vat stored therein and said remote server having a memory allocation in said storage means that is reserved for each one of at least said vat with said univocal identification code, said remote server being configured to:
- receive said univocal identification code related to at least said vat from said data processing unit;
- compare said univocal identification code with said predefined list in order to verify that said univocal identification code is authentic and active;
- send a signal of validity of said univocal identification code to said data processing unit in the case where said univocal identification code is authentic and active;
- said transceiver means of said data processing unit furthermore being configured to receive said signal of validity, and said data processing unit being configured to enable the use of said vat in the stereolithography machine where at least said vat is installed in case of reception of said signal of validity, and said remote server furthermore being configured to:
- associate said vat with the number of uses of said vat by storing said number in said memory allocation;
- associate said vat with a type of base material transferred therein by storing said type of base material in said memory allocation;
- modify the state of said univocal identification code related to said vat from active to inactive in said predefined list, in a case where said number of uses reaches or exceeds a predefined number of uses.