Process of lost wax micro casting with recycling of exhausted wax

Process of lost wax micro casting with recycling of exhausted wax, comprising the steps of:

• molding of one or more wax models, identical to the end pieces to produce, using a first formulation of wax;
• molding of one or more molds of sprues (connecting passages), using a second formulation of wax;
• assembling of said one or more models and said one or more molds of sprues, to form a cluster;
• coating of said cluster with a ceramic shell;
• removing of wax from said shell;
• treating of said shell in an oven;
• casting of molten metal alloy within said shell and subsequent cooling to obtain a solidified casting;
• cracking of the shell to release the solidified casting;
• removing of the sprues and finishing of the pieces;
• and characterised in that it additionally comprises the following steps:
• melting of the exhausted wax coming from said step of removing wax from said shell, to obtain a molten exhausted wax;
• removing of water from said molten exhausted wax, to obtain de-hydrated molten exhausted wax;
• removing of ceramic residues, ashes or other impurity by filtration of said de-hydrated molten exhausted wax, to obtain recycled wax;
• adding virgin wax (grade 50-60° C.) in a quantity equal to at least 30% by weight of the total of the recycled wax, and at least equal to the amount of recycled wax in the case in which the same has been already obtained following a process of lost wax micro casting in which a wax formulation that contain recycled wax was used, to obtain said second formulation of wax;
• delivering of said second formulation of wax to said molding of one or more molds of sprues;
• wherein said second formulation of wax has the following properties:
• freezing point:
• 58-64° C.
• metting point (drop melt point):
• 65-71° C.
• ash content:
• ≤0.05% by weight
• penetration:
• 8-14 dmm
• viscosity at 70° C.:
• 0.6-1.3 Pa·s
• where the penetration is measured accordin to ASTM D1321 needle enetration of petroleum waxes), using a weight equal to 250 g and the viscosity is measured using a Haake RV1 absolute viscometer with a ISO 3219 Z34 DIN cylindrical rotor with, a diameter of 34 mm, using a cutting speed of 54.5 s-1 and a cooling rate of 1 degree per minute in a temperature range that starts from 85° C. to 60° C.