Process for manufacturing a shell mold
AssigneesSafran, Safran Aircraft Engines
InventorsWen Marie Gérard ZHANG, Patrice Henri Claude RAGOT
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Abstract
The invention concerns a method of manufacturing a shell mould (1) with several layers (2, 3, 4, 5), including at least one contact layer (2), from a model (6) of wax or other similar material of a part to be manufactured, the method comprising a step of dipping the model (6) into a contact slip forming the contact layer (2) and comprising an inorganic or organic binder and a powder, wherein the powder is a mullite-zirconia composite.
Claims13
A method for manufacturing a shell mould (1) with several layers (2, 3, 4, 5) including at least one contact layer (2), from a model (6) of wax or other similar material of a part to be manufactured, the method comprising a step of dipping the model (6) into a contact slip forming the contact layer (2) and comprising a binder and a powder, characterized in that the powder comprises a mullite-zirconia composite.
Process according to the previous claim, in which the zirconia content in the powder is between 10% and 50% by weight.
A process according to any one of the foregoing claims, wherein the particles of the mullite-zirconia composite powder have an average size between 5 and 20 μm.
A process according to any one of the foregoing claims, wherein the contact layer has a thickness less than or equal to 1 mm.
A process according to any one of the foregoing claims, wherein the binder is colloidal silica.
A process according to any of the above claims, wherein the contact slip also comprises at least one wetting agent and/or at least one antifoaming agent.
A process according to any of the foregoing claims, which comprises, following soaking of the model (6) in the contact slip, the steps wherein:
- the model (6) is sandblasted,
- the sandblasted model (6) is dried,
- the sandblasted and dried model (6) is dipped in a second slip, preferably without zirconia,
- the model (6) dipped in the second slip is coated with a reinforcing material,
- the model (6) coated with the reinforcing material is dried, and
- the model (6) coated with the reinforcing material and dried is subjected to heat treatment.
A process according to the previous claim, in which the steps of soaking in the second slip, coating in the reinforcing material and drying the model (6) coated with the reinforcing material and dried are repeated.
A process according to any of the foregoing claims, which, prior to soaking the model (6) in the contact slip, comprises a phase of making the contact slip comprising the steps of:
- introducing the mineral colloidal binder into a container, in this case a mixer,
- adding the mullite-zirconia composite powder to the mixer,
- allowing the mixture of mineral colloidal binder and powder to stabilize.
Use of a mould (1) obtained by the process of any of the above claims for the manufacture of a cast and solidified turbomachine part.
Dependencies are inferred from the claim text.