The tangram is a Chinese dissection puzzle, consisting of seven flat shapes, called tans, which are put together to form assorted silhouettes. Starting from the customer’s order, the Mini-Factory assembles the desired game-set, either taking components and boxes from the warehouse or by manufacturing the missing ones. The Mini-Factory is usually busy with the production of game-sets made to stock, to be gifted to visitors and partners as a gadget. A visiting customer, using a configurator running on a tablet, can customize his own tangram, choosing from an extensive range of personalization options, including: 4 choices of colour of each tan, 2 type of boxes (plastic or wood), and a choice among 6 totemic animals to be engraved on the wooden box.
The production process
Once the customer has configured the personalized tangram, the scheduler rearranges the to-stock production, to make room for the new order (the customized order, while given priority, coexists with the production of the to-stock tangrams). The system checks the components already available in the warehouse and, if something is missing, commands the production of those elements. The warehouse nominal status is known to the system, but the actual status is verified though RFID tags (corrections, if needed, are made automatically). Likewise, the system checks for the production modules status and capacity to perform given tasks (the modules self-declare their status and an array of smart cameras accurately define their location, to self-adapt to variation in configuration and position) and assigns the realization of the missing components to the more suitable module. The needed components are retrieved from the warehouse by a cartesian robot and they are moved to the assembly station, by means of a carriage driven by a transportation system based on a linear motor. The transportation system features two carriages that can be moved independently one from the other. The carriage commutes back and forth from the warehouse, to collect all the components. On the way out of the warehouse, the geometrical features of the components are checked by a laser scanner, both to perform a quality check, and to acquire the real geometry of the tans, which may differ from the nominal one. In the assembly station, a SCARA robot starts the assembly procedure. The SCARA is equipped with an intelligent vision system to correctly pick the tans, even if misplaced, and to detect and correct possible failures in the assembly process (no mechanical jigs are in place, as the process is fully driven by an extensive use of machine vision). The SCARA is also tasked to retrieve the newly produced tans from the production modules: once the modules are finished 3D printing the required components, the SCARA picks up the printing-bed and places it on the detachment station. The tans are then brought to the assembly station. The positioning of the selected cover on the top of the box completes the assembly process. The boxed tangram is eventually picked by the SCARA robot from the assembly table and brought to the warehouse by the carriage.