EP4308326A1

EP4308326A1 - Method for manufacturing a fan disc with a part by additive manufacturing

Info

Publication number: EP4308326A1
Application number: EP22714230.4A
Authority: EP
Inventors: Alexandre Michel Henri Hasquenoph; Hamza Guessine; Jeremy Smith; Antonin VIGOURT
Original assignee: Safran Aircraft Engines SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 2021-03-16
Filing date: 2022-03-11
Publication date: 2024-01-24
Also published as: US20240227004A1; CN116997427A; WO2022195207A1; FR3120813B1; FR3120813A1

Abstract

The method for manufacturing a fan disc (3) of a turbine engine (1) according to the invention is characterized in that it comprises the following steps: - a step FO of forging a first cylindrical shape (60) of axis X, - a step U of machining the first cylindrical shape (60) to obtain a second cylindrical shape (61), - a step FA of adding, by additive manufacturing, at least one relief element (33, 31, 350) to the second cylindrical shape (61).

Description

DESCRIPTION

TITLE: Process for manufacturing a fan disc with part in additive manufacturing

TECHNICAL FIELD OF THE INVENTION

The technical field of the invention is that of aeronautical turbine engines, in particular turbine engines with a very high bypass rate and more particularly the fan disk fitted to said engines.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] The fan disk is located in the upstream part of the turbine engine and carries the blades. Its main function is to transmit torque from the low pressure compressor shaft to the blades.

The blades are mounted on the periphery of the disc by engagement of the blade roots in cells formed on the periphery of the disc in the form of grooves for the radial retention of the blade roots. This disk is described in particular in documents EP 1 400 698, FR 3 081 520, FR 3 048 997. It comprises a plurality of substantially axial grooves regularly distributed angularly and intended to receive a plurality of removable blades which extend radially outwards at the periphery of said disk, each blade comprising a blade root seated in a groove. It also has several protruding perforated nipples on its rear periphery which complete the attachment of the blades. Two raised internal ferrules are also provided at the front and rear for front attachment of the blades and for attachment of the fan disc to the drive shaft. These different elements must be machined from a raw part.

[0004] The fan is subjected to significant stresses, it is therefore necessary to use materials with improved properties which are obtained by means of a forging process.

[0005] Current manufacturing methods use conventional manufacturing means (milling machine, lathe, etc.) to produce the fan disk. These methods impose a pre-machining as well as a large blank encompassing the entire part, ie the blank has an envelope that covers all the roughness of the finished part. The pre-machined are heavy and expensive because of large dimensions, they require a prolonged machining cycle and a significant loss of chips, resulting in a lot of wasted material and a high manufacturing cost.

SUMMARY OF THE INVENTION

The invention offers a solution to the problems mentioned above, by greatly reducing the size of the rough and the pre-machined, by reducing the costs of obtaining the rough and the pre-machined which are of simpler form while offering both the possibility of changing the material and, potentially, gaining mass on the finished part, and of producing new shapes that cannot be manufactured with conventional means for secondary functions.

The object of the invention is to produce the disk partly by additive manufacturing.

[0008] The method of manufacturing a fan disk of a turbine engine according to the invention is characterized in that it comprises the following steps: a step of forging a first cylindrical shape with axis X, a step machining the first cylindrical shape to obtain a second cylindrical shape, a step of adding by additive manufacturing at least one element in relief on the second cylindrical shape.

[0009] The first cylindrical shape is a simplified raw part which includes the main parts of the disc without the various raised parts, in particular those of small sizes, such as the studs and the ferrules, it is therefore smaller and of more simple as the raw part of the state of the art. It is therefore lighter and less bulky, and therefore less expensive.

[0010] The second cylindrical shape made from the first cylindrical shape is a semi-finished part which does not include the elements in relief. It is also lighter and less bulky. The part is less expensive because not only is there less material, but also less material is lost during machining.

[0011] The various elements in relief are added by additive manufacturing in the areas that have been simplified. But elements in relief can be placed where desired and have new shapes not achievable with means conventional. The simplified zones, which can correspond to stress functions that do not need the same material characteristics as the main body, are added by an additive manufacturing process using the same material or another with more interesting properties compared to the needs (lower density, better tensile strength, etc.).

[0012] In addition to the characteristics which have just been mentioned in the previous paragraph, the method according to the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations.

[0013] Advantageously, the second cylindrical shape has an outer face and an inner face, and the element in relief is located on the outer face of the second cylindrical shape. The relief element is added by additive manufacturing on the outer face of the second cylindrical shape, there can be one or more, they can be continuous or discontinuous.

[0014] Advantageously, the second cylindrical shape has an outer face and an inner face and the element in relief is located on the inner face of the second cylindrical shape. The relief element is added by additive manufacturing on the inner face of the second cylindrical shape, there can be one or more, they can be continuous or discontinuous

[0015] Advantageously, the element in relief is circular with an X axis. It can be located inside or outside the second cylindrical shape, at the front or at the rear of the latter. It may include fixing elements and therefore be perforated. This element can for example constitute a ferrule.

[0016] Advantageously, the element in relief is a stud. The nipple is protruding and semi-circular in shape connected to the second cylindrical shape.

[0017] Advantageously, the stud is pierced along an X' axis. The hole is used to fix the blade and it can also be tapped.

[0018] Advantageously, the X' axis is parallel to the X axis.

[0019] Advantageously, several studs are added to the outside of the second cylindrical shape. Preferably, there will be at least as many nipples as blades. [0020] Advantageously, the studs are arranged in a circular manner on the second form. The nipples will, for example, allow the rear fixing of each blade.

The invention also relates to a fan disk obtained by the process according to with at least one of the preceding characteristics.

BRIEF DESCRIPTION OF FIGURES

The figures are presented for information only and in no way limit the invention.

[0023] [Fig. 1] is a cross-section of the front end of a turbine engine with a state-of-the-art fan disk;

[0024] [Fig. 2] shows detail ll-ll of figure 1 showing the raw part and the finished part made with a process of the state of the art;

[0025] [Fig. 3] is a perspective view of another prior art fan disk; [0026] [Fig. 4] is a cross-section of part of the fan in FIG. 3 showing the raw part and the finished part produced using a prior art process;

[0027] [Fig. 5] is a section of the part of FIG. 1 showing the raw part and the finished part made with a method according to the invention;

[0028] [Fig. 6] is a section of the part of figure 4 showing the raw part and the finished part produced with a method according to the invention

[0029] [Fig. 7] shows the steps of the method according to the invention.

DETAILED DESCRIPTION

The figures are presented for information only and in no way limit the invention. [0031] Unless specified otherwise, the same element appearing in different figures has a single reference.

[0032] Throughout the description, the upstream part of the turbine engine will be called "front" in the direction of the air flow according to arrow A and "rear", the downstream part. The part located towards the inside of the cylindrical part will be called “inner”, and the “outer” on the outer part will be called.

The turbine engine 1 comprises blades 2 and a fan disk 3 on which the blades 2 are arranged. The turbine engine 1 and the fan disk 3 have a common axis X. The fan disk 3 is hollow and cylindrical in shape.

We can see on another example of disc is shown in perspective in Figure 3, which shows that this disc has a very complex shape and has a large number of asperities both on the outside, on the inside, front and back.

[0035] For a better understanding, only one side of the section of the fan disc 3 is shown in Figures 2, 4, 5 and 6, the axis X being an axis of symmetry.

In the section of Figure 2, the shape of the blank 4 is shown by the solid line while the profile of the fan disk 3 is dotted. The fan disc 3 comprises studs 33 on its outer surface and a front shroud 31 on its front part and a rear shroud 32 on its rear part, as well as feet 34 inside. The studs 33 and the front shroud 31 are used to fix the blades 2, while the rear shroud 32 is fixed to the shaft 5. All these elements in relief must be contained in the blank 4 to obtain a one-piece part able to meet to the different opposites undergone by the blades 2.

[0037] The realization of the fan disc 3 from the blank 4 according to the state of the art is as follows: production of a blank 4 of annular shape by forging roughly enveloping the entire final part and, machining of the blank 4 by the outside to precisely produce the outer roughness such as the pins 33, but also grooves 36 on the outer surface 301, machining of the blank 4 from the inside to precisely produce the inner roughness such as the feet 34 on the inner surface 300 , machining of the blank 4 from the front and from the rear to precisely produce the front asperities such as the front ferrule 31 and rear such as the rear ferrule 32. [0038] It is understood that the blank 4 cannot have a complex shape or be cut too much, it must always be machined to respect the dimensions and shapes necessary for the production of the final part. Indeed, the final part must meet certain tolerances that are incompatible with forged parts. The machining steps are all the longer and more complex as the fan disc 3 is cut out and has a number of asperities.

Thus, as can be seen in the example illustrated in Figure 2, the blank part 4 is delimited by a thick line representing a first cylindrical shape 40 while the final part is delimited by a dotted line 30. he difference between the two lines represents all the material lost by the machining which is significant. One can also see the complexity of the shapes to be made by machining, in particular the fine parts such as the studs 33 perforated along an X' axis, and the front 31 and rear 32 ferrules, the latter also having particularly complicated profiles to develop. .

In the second example of Figures 3 and 4, the profile of the fan disc 3 is different in its inner part and its rear part. Thus the fan disc 3 has studs 33 perforated along an axis X', a front shroud 31 and an inner arm 35 intended to fix the fan disc 3 on the shaft 5. This inner arm 35 forms a U with the surface interior 300 of the fan disc 3. But the manufacturing process is identical.

In Figure 4, the blank 4 is delimited by a continuous line representing a first cylindrical shape 40 and the fan disc 3 by a continuous line 30 with the interior hatched. The gap between the lines shows the material lost by machining which is also important. Here again, the shapes to be produced are very cut out and complex to produce by machining. In particular, the studs 33 are first formed externally by a first machining then they are perforated along an axis X', then possibly tapped by a second machining.

[0042] With the method according to the invention, the fan discs 3 are made differently, since it consists of using three different techniques: forging, machining and additive manufacturing.

The first step indicated by the reference FO in Figure 7, is a step of producing by forging a low elaborate crude 6 having a simple profile in a first cylindrical shape smaller than that of the known method. The second step consists of a machining operation referenced U in Figure 7, this step U makes it possible to achieve the general shape of the fan disc 3 without its roughness in a second cylindrical shape. This step U is simpler than that of the state of the art since there are fewer shapes to be made by machining and they are less complex.

The third step referenced FA in Figure 7, makes it possible to achieve all the missing roughnesses to obtain the final shape of the fan disk 3. These roughnesses can have more complex shapes than those made by simple machining as in the process of the state of the art.

Thus, as can be seen in the example illustrated in Figure 5, the blank part 6 is delimited by a thick line representing a first cylindrical shape 60 while the final part is delimited by a dotted line 30. can see that the final shape represented by the dotted line 30 is divided into two parts: a first part 302 placed inside the first cylindrical shape 60 and a second part 303 placed outside the first cylindrical shape 60. The difference between the first line 302 and the first cylindrical shape 60 represents all the material lost by the machining which is less than that of FIG.

In Figure 4, the blank 4 is delimited by a continuous line representing a first cylindrical shape 60 and the fan disk 3 by a continuous line 30 with the interior hatched. It can be seen that the final shape represented by the continuous line 30 is broken down into two parts: a first part 302 arranged inside the first cylindrical shape 60 and a second part 303 arranged outside the first cylindrical shape 60 The gap between the line 302 and the first cylindrical shape 60 shows the material lost by machining which is also less than that of Figure 6.

The forging step FO therefore consists in producing the blank 6 according to a first cylindrical shape 60.

The machining step U consists in eliminating the material between the cylindrical shape 60 and the first part 302 of the line 30, in order to produce a second cylindrical shape 61. The last step FA of additive manufacturing makes it possible to produce all the roughness not contained in the second cylindrical shape 61. This second cylindrical shape 61 has an internal face 610 and an external face 611.

[0051] Thus for the fan disc shape 3 illustrated in Figure 5, the forged part is in the form of the blank 6 enveloping only part of the final part, in fact the first cylindrical shape 60 does not include the protruding parts such as the studs 33 and the front shell 31. Once the machining of the blank 6 has been completed, a second cylindrical shape 61 is obtained delimited by the dotted line 302. On this second cylindrical shape 61 the studs 33 are added and the front shroud 31 by additive manufacturing up to line 303.

For the example of Figure 6, in the same way a blank 6 is produced by forging, this blank constituting a first cylindrical shape 60 does not include either the nipples 33, or the front pox 31, or the end 350 of the arm 35. Then the machining is carried out which makes it possible to achieve the second cylindrical shape 61 delimited by the hatched part and the line 302. The projecting parts are then produced by additive manufacturing up to the line 303.

Two examples of fan discs have been shown, but it is possible, thanks to the method according to the invention, to produce more protruding shapes and shapes different from those shown.

Claims

[Claim 1] Method of manufacturing a fan disc (3) of a turbine engine (1), comprising the following steps:

- a forging step FO of a first cylindrical shape (60) of axis

x,

- a step U of machining the first cylindrical shape (60) to obtain a second cylindrical shape (61),

- a step FA of adding by additive manufacturing at least one element in relief (33, 31, 350) on the second cylindrical shape (61), characterized in that the second cylindrical shape (61) has an outer face ( 611) and an interior face (610) and that the relief element (350) is located on the interior face (610) of the second cylindrical form (61).

[Claim 2] Process according to Claim 1, characterized in that the second cylindrical shape (61) has an outer face (611) and an inner face (610) and that the element in relief (33) is located on the face exterior (611) of the second cylindrical shape (61).

[Claim 3] Method according to one of the preceding claims, characterized in that the element in relief (31, 350) is circular with an X axis.

[Claim 4] Method according to one of the preceding claims, characterized in that the element in relief is a stud (33).

[Claim 5] Method according to the preceding claim, characterized in that the stud (33) is pierced along an axis X'.

[Claim 6] Method according to claim 5, characterized in that the X' axis is parallel to the X axis.

[Claim 7] Method according to one of Claims 4 to 6, characterized in that several studs (33) are added to the outside of the second cylindrical form (61).

[Claim 8] Method according to the preceding claim, characterized in that the studs (33) are arranged in a circular manner on the second cylindrical form (61).

[Claim 9] Fan disc (3) obtained by the process according to one of the preceding claims.