3D printing method for wax mold of large-size thin-wall complex-structure high-temperature alloy barrel

Abstract

The invention discloses a 3D printing method for a wax mold of a large-size thin-wall complex-structure high-temperature alloy barrel, and relates to the technical field of high-temperature alloy investment precision casting. The problems that when a large-size thin-wall complex inner cavity structure high-temperature alloy barrel is manufactured through 3D printing, the positions of a thin-wall structure and a special structure are difficult to form, a local structure of a product reversely deforms, a formed auxiliary supporting structure is difficult to remove, and the product percent of pass is low are solved. The method comprises the following steps: firstly, optimizing a digital-analog overall size structure, carrying out process correction on a large thin-wall area which is easy to deform and difficult to form, and carrying out reasonable scale reduction on different parts; an auxiliary supporting structure is placed and formed at the position, prone to local deformation or a large window, in the complex thin-wall structure; then, the overall digital model is imported into rapid prototyping equipment for printing, and then powder cleaning is conducted; the auxiliary supporting structure is protected after powder removal, and then overall wax hanging is conducted; and finally, the formed auxiliary supporting structure is removed, and the surface of the wax piece is trimmed. The method is suitable for the technical field of high-temperature alloy investment precision casting.

Description

Technical Field

[0001] The present invention relates to the technical field of investment precision casting of superalloys, and particularly relates to a 3D printing method for wax patterns of large-size thin-walled complex-structure superalloy cylinders. Background Art

[0002] With the continuous development of the aerospace field, the internal structure of superalloy products is becoming thinner-walled, more complex, and larger in size. Facing the continuous shortening of the R & D cycle of large complex thin-walled structure products, the rapid prototyping technology has been continuously applied, which can greatly shorten the R & D cycle. However, for wax parts of large complex thin-walled structures, thin-walled structures, and rotary cylinder large structural parts, it is difficult to form, and the process yield is low. During the preparation process, there are production problems such as difficult forming at the thin-walled structure positions and special structure positions, serious reverse deformation of local structures, and complex removal of auxiliary support structures.

[0003] In summary, when the existing 3D rapid prototyping preparation method is used to manufacture a large-size thin-walled complex internal cavity structure superalloy cylinder, it is difficult to form at the thin-walled structure positions and special window structure positions, and the local structure of the product has reverse deformation, and it is difficult to remove the forming auxiliary support structure, resulting in a low qualified rate of the product. Summary of the Invention

[0004] In order to solve the problems that when the 3D rapid prototyping preparation method is used to manufacture a large-size thin-walled complex internal cavity structure superalloy cylinder, it is difficult to form at the thin-walled structure positions and special window structure positions, and the local structure of the product has reverse deformation, and it is difficult to remove the forming auxiliary support structure, resulting in a low qualified rate of the product, the present invention proposes a 3D rapid preparation method for wax patterns of large-size thin-walled internal cavity structure superalloy cylinders.

[0005] A 3D printing method for wax patterns of large-size thin-walled complex-structure superalloy cylinders of the present invention is as follows:

[0006] Step 1: Optimize the overall dimensional structure of the digital model, perform process correction on the easily deformed, difficult-to-form, and large thin-walled regions, and perform reasonable scaling at different parts;

[0007] Step 2: Place forming auxiliary support structures at positions where local deformation is likely to occur in the thin-walled complex structure or at large windows;

[0008] Step 3: Import the overall digital model into a rapid prototyping device and perform overall rapid prototyping printing;

[0009] Step 4: Remove the powder from the sample after printing;

[0010] Step 5: Protect the auxiliary support structure after powder removal, and then perform overall wax dipping;

[0011] Step Six: Remove the forming auxiliary support structure and trim the surface of the rapid prototyping wax part, thus completing the preparation of the 3D rapid prototyping of the large-sized thin-walled complex internal cavity structure high-temperature alloy cylinder;

[0012] Further, in Step One, partial parts in the overall digital model are scaled down. Due to different solidification shrinkages of the high-temperature alloy material, the scaling ratio of the thin-walled structure is between 1.2% and 1.5%;

[0013] Further, in Step Two, at the large window forming position, auxiliary support is pre-carried out, the window structure is blocked, and an auxiliary support structure is set below;

[0014] Further, the auxiliary support structure adopts a thin plate type support structure;

[0015] Further, the thickness of the auxiliary support structure is between 1 mm and 2 mm;

[0016] Further, in Step Five, after powder cleaning, the auxiliary support structure is protected, and the protection method is to wind and wrap the auxiliary support structure with a thin transparent tape.

[0017] The present invention has the following beneficial effects compared with the prior art:

[0018] The present invention overcomes the shortcomings of the prior art. First, it optimizes the overall dimension structure of the digital model, makes process corrections for the easily deformed, difficult-to-form, and large thin-walled areas, and performs reasonable scaling at different parts; then places a forming auxiliary support structure at the position where local deformation is likely to occur in the thin-walled structure or at the large window; then imports the overall digital model into the rapid prototyping equipment for overall rapid prototyping printing; clears the powder from the printed sample; protects the auxiliary support structure after powder cleaning, and then performs overall wax hanging; finally, removes the forming auxiliary support structure and trims the surface of the rapid prototyping wax part; this rapid prototyping preparation method is applicable to the preparation of large cylinder thin-walled complex structures, can realize the forming of special forming structures, and can effectively ensure the overall forming dimension accuracy; using this method can solve the problem of complex removal of the auxiliary support structure, provide effective structural strength for the processes of wax part preparation, powder cleaning, wax hanging, and repair, solve the problem of difficult forming in the large thin-walled structure position and special structure position, and avoid the phenomenon of reverse deformation of the local structure of the product, thereby greatly improving the qualified rate of the product;

[0019] In the 3D printing method, the reasonable placement of the forming auxiliary support structure can not only effectively solve the forming problem of the feature position, but also avoid dimensional deformation during the forming process, ensuring the overall dimensional accuracy. And after powder cleaning, the support structure is protected by a special protection device, and combined with the auxiliary support structure using a thin plate support structure, so as to realize the rapid removal of the auxiliary support structure and improve production efficiency. Description of the Drawings

[0020] Figure 1 It is a three-dimensional schematic diagram of the product prepared by using the 3D printing method for a large-size thin-wall complex-structure superalloy cylinder wax mold described in the present invention;

[0021] Figure 2 It is an axonometric sectional view of the product prepared by using the 3D printing method for a large-size thin-wall complex-structure superalloy cylinder wax mold described in the present invention;

[0022] Figure 3 It is an axonometric view of placing the auxiliary support structure during the preparation process by using the 3D printing method for a large-size thin-wall complex-structure superalloy cylinder wax mold described in the present invention;

[0023] Figure 4 It is a reverse axonometric view of placing the auxiliary support structure during the preparation process by using the 3D printing method for a large-size thin-wall complex-structure superalloy cylinder wax mold described in the present invention. Detailed Embodiments

[0024] Detailed Embodiment 1: The 3D printing method for a large-size thin-wall complex-structure superalloy cylinder wax mold described in this embodiment is as follows:

[0025] Step 1: Optimize the overall dimensional structure of the digital model, perform process correction on the areas prone to deformation, difficult to form, and large thin-walled areas, and perform reasonable scaling at different parts;

[0026] Step 2: Place the forming auxiliary support structure at the positions prone to local deformation or large windows in the thin-wall complex structure;

[0027] Step 3: Import the overall digital model into the rapid prototyping equipment and perform overall rapid prototyping printing;

[0028] Step 4: Powder clean the sample after printing;

[0029] Step 5: Protect the auxiliary support structure after powder cleaning and then perform overall wax hanging;

[0030] Step 6: Remove the forming auxiliary support structure and trim the surface of the rapid prototyping wax part, thus completing the preparation of the 3D rapid prototyping of the large-size thin-wall complex inner cavity structure superalloy cylinder.

[0031] In this specific implementation, the overall size structure of the digital model is optimized first. Process corrections are made for areas prone to deformation, difficult to form, and large thin-walled regions, and reasonable scale reduction is placed at different positions. Then, forming auxiliary support structures are placed at positions in the thin-walled structure where local deformation is likely to occur or at large windows to avoid fragmentation and deformation during powder cleaning or wax dipping. Then, the overall digital model is imported into a rapid prototyping device for overall rapid prototyping printing. The sample after printing is subjected to powder cleaning. The auxiliary support structure is protected after powder cleaning, and then the whole is wax-dipped. Finally, the forming auxiliary support structure is removed, and the surface of the rapid prototyping wax part is trimmed. This rapid prototyping preparation method is applicable to the preparation of large cylindrical thin-walled complex structures, can realize the forming of special forming structures, and can effectively ensure the overall forming size accuracy. Using this method can solve the problem of complex removal of the auxiliary support structure, provide effective structural strength for the processes of wax part preparation, powder cleaning, wax dipping, and repair, solve the problem of difficult forming at the positions of large thin-walled structures and special structure positions, and avoid the phenomenon of reverse deformation of local structures of the product, thus greatly improving the qualified rate of the product.

[0032] Specific implementation method two: This implementation method is a further limitation on the 3D rapid preparation method described in specific implementation method one. For a 3D printing method of a large-size thin-walled complex structure superalloy cylinder wax mold described in this implementation method, in step one, scale reduction is performed on some parts of the overall digital model. Due to different solidification shrinkages of superalloy materials, the scale reduction ratio of the thin-walled structure is between 1.2% and 1.5%.

[0033] Specific implementation method three: This implementation method is a further limitation on the 3D rapid preparation method described in specific implementation method one. For a 3D printing method of a large-size thin-walled complex structure superalloy cylinder wax mold described in this implementation method, in step two, at the forming position of a large window, auxiliary support is pre-performed and the window structure is blocked, and an auxiliary support structure is arranged below.

[0034] Specific implementation method four: This implementation method is a further limitation on the 3D rapid preparation method described in specific implementation method three. For a 3D printing method of a large-size thin-walled complex structure superalloy cylinder wax mold described in this implementation method, the auxiliary support structure adopts a thin plate type support structure.

[0035] Specific implementation method five: This implementation method is a further limitation on the 3D rapid preparation method described in specific implementation method four. For a 3D printing method of a large-size thin-walled complex structure superalloy cylinder wax mold described in this implementation method, the thickness of the auxiliary support structure is between 1 mm and 2 mm.

[0036] Embodiment Six: This embodiment further limits the 3D rapid preparation method described in Embodiment One. In a 3D printing method for a large-sized thin-walled complex-structure superalloy cylinder wax mold described in this embodiment, in Step Five, after powder cleaning, the auxiliary support structure is protected. The protection method is to wrap the auxiliary support structure with thin transparent tape.

[0037] In this specific embodiment, the protection method of wrapping the auxiliary support structure with thin transparent tape can greatly simplify the removal step of the auxiliary support structure, ensure the overall dimensional accuracy, and improve the production efficiency.

[0038] Example

[0039] Combined with Figures 1 to 4 As shown, a 3D printing method for a large-sized thin-walled complex-structure superalloy cylinder wax mold described in the present invention has the following specific steps:

[0040] Step One: The external dimensions of the digital model are 550×350×300 mm, and there are also various complex structures in the inner cavity, and large-area large windows are opened; optimize the overall dimensional structure of the digital model, perform process correction on the easily deformed and large thin-walled areas, and place reasonable shrinkage scales at different positions; place a shrinkage scale of 1.2 - 1.5% at the thin-walled part. Different shrinkage scales are placed in the length direction and set in the axial direction.

[0041] Step Two: Place forming auxiliary support structures at the positions in the thin-walled structure that are prone to local deformation or at the large windows to avoid cracking and deformation during powder cleaning or wax hanging; set thin-plate-shaped auxiliary support structures at the positions where the thin and thick transitions are prone to deformation, and the thickness of the support structure is 1 mm - 2 mm; the thin-plate-shaped auxiliary support structure can adjust the height along with the inner cavity height, and while providing support, it does not increase the local cross-sectional area, avoiding large heat input during the laser sintering process, and effectively avoiding deformation while providing effective support.

[0042] Step Three: Import the overall digital model into the rapid prototyping equipment for overall rapid prototyping printing.

[0043] Step Four: After printing, clean the powder from the wax part; remove the excess powder in the inner cavity, and retain the auxiliary support structure during the powder cleaning process; for blocking the large-sized windows on the surface, process holes with a diameter of 5 - 10 mm can be opened to facilitate cleaning the residual powder.

[0044] Step Five: After powder cleaning, wrap the auxiliary support structure with thin tape to prevent the auxiliary support structure from hanging wax; avoid the auxiliary support structure being too strong to remove after the overall wax hanging in the later stage; the wax hanging material is white paraffin, the wax temperature is 65°C - 70°C, the wax hanging time is 30S, and repeat 2 - 3 times; avoid cracking and deformation caused by one-time wax hanging of large-area thin-walled structures.

[0045] Step VI. After waxing, the forming auxiliary support structure is removed as a whole, and the surface of the rapid prototyping wax part is polished to complete the preparation of the 3D rapid prototyping of the large-size thin-walled internal cavity structure superalloy cylinder.

Claims

1. A 3D printing method for a large-sized thin-walled complex structure superalloy cylinder wax mold, characterized in that: The specific method is as follows: Step 1: Optimize the overall size structure of the digital model, perform process correction on areas prone to deformation, difficult to form, and large thin-walled areas, and carry out reasonable scaling at different parts; Step 2: Place forming auxiliary support structures at positions prone to local deformation or large windows in the thin-walled complex structure; Step 3: Import the overall digital model into a rapid prototyping device for overall rapid prototyping printing; Step 4: Remove the powder from the sample after printing; Step 5: Protect the auxiliary support structure after powder removal, and then perform wax dipping as a whole; Step 6: Remove the forming auxiliary support structure and trim the surface of the rapid prototyping wax part, thereby completing the preparation of the 3D rapid prototyping of the large-size thin-walled complex internal cavity structure superalloy cylinder.

2. The 3D printing method of a large-sized thin-walled complex structure superalloy cylinder wax mold according to claim 1, characterized in that: In Step 1, scaling is performed on some parts of the overall digital model. Due to different solidification shrinkages of the superalloy material, the scaling ratio of the thin-walled structure is between 1.2% and 1.5%.

3. A 3D printing method for a large-size thin-walled complex structure superalloy cylinder wax mold according to claim 1, characterized in that: In Step 2, at the forming position of the large window, auxiliary support is pre-carried out and the window structure is blocked, and an auxiliary support structure is set below.

4. A 3D printing method for a large-sized thin-walled complex structure superalloy cylinder wax mold according to claim 3, characterized in that: The auxiliary support structure adopts a thin plate type support structure.

5. A 3D printing method for a large-sized thin-walled complex structure superalloy cylinder wax mold according to claim 4, characterized in that: The thickness of the auxiliary support structure is between 1 mm and 2 mm.

6. A 3D printing method for a large-size thin-walled complex-structure superalloy cylinder wax mold according to claim 1, characterized in that: In Step 5, after powder removal, the auxiliary support structure is protected. The protection method is to wrap the auxiliary support structure with a thin transparent tape.

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