CN112496341B - Laser selective melting forming and post-processing method for thin-wall interlayer cooling structure - Google Patents
Laser selective melting forming and post-processing method for thin-wall interlayer cooling structure Download PDFInfo
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Abstract
The invention relates to the technical field of additive manufacturing, and discloses a selective laser melting forming and post-processing method for a thin-wall interlayer cooling structure, which comprises the following steps: (1) Optimizing the design based on the additive manufacturing technology and establishing a three-dimensional model; (2) placing the established models according to requirements; (3) Intercepting partial parts to perform forming and post-processing tests, and performing iterative optimization on the model according to a liquid flow result; (4) adding a support; (5) selective laser melting and forming; (6) Cleaning powder, filling wax for protection (7), removing external support by adopting methods such as wire cut electrical discharge machining, manual polishing and the like, and performing dewaxing treatment after finishing; (8) Heat treatment and chemical polishing are adopted to polish the inner surface of the thin-wall interlayer, so that the smoothness of the inner cavity meets the requirement.
Description
Technical Field
The invention relates to the technical field of additive manufacturing, in particular to a selective laser melting forming and post-processing method for a thin-wall interlayer cooling structure.
Background
The thin-wall interlayer cooling structure is a main structural form which effectively ensures the normal service of a rocket engine thrust chamber in a high-temperature and high-pressure environment, and is mainly applied to a combustion chamber, a contraction and expansion section and an expansion section. The combustion chamber is a place for mixing and combusting the propellant, and the fuel and the oxidant are fully mixed and combusted at the place to generate high-temperature fuel gas. The contraction and expansion section is a key part in the thrust chamber and is of a double-bell structure, one end of the contraction and expansion section is connected with the combustion chamber, and the other end of the contraction and expansion section is connected with the expansion section. When the engine works, the throat part of the thrust chamber body is in a high-temperature and high-pressure environment, the working environment is extremely severe, the working temperature reaches 3500K, and the high-temperature gas scouring speed exceeds 1000m/s. The traditional manufacturing process method cannot directly and integrally form the interlayer cooling structure and adopts the inner and outer wall brazing process to manufacture. The processing technology has the following problems: first, the performance stability is poor. The cooling body part of the interlayer of the thrust chamber adopts an inner wall and outer wall brazing process, so that the problem of blockage or bulge of a cooling channel caused by uneven overflow of brazing materials often occurs, and the service performance of a product is influenced. In addition, the body part adopts a split welding process after sectional brazing, and because the deformation of each section after brazing causes poor butt joint precision and poor weld quality during split welding of each section, the quality and the stability of the engine are reduced. Second, the yield is low. When the inner wall and the outer wall of the thrust chamber interlayer cooling assembly are assembled, the inner wall needs to be expanded to enable the inner wall and the outer wall to be attached, and due to material resilience, the brazing gap between the inner wall and the outer wall at the small end after expansion is large, so that the brazing quality is poor, and when the subsequent hydraulic test examination is carried out, the problems of pressing, bulging and the like can occur in a weak brazing seam area, so that the product is scrapped. Thirdly, the processing period is long. The force chamber interlayer cooling assembly cannot be integrally formed by adopting the traditional process, so that the force chamber interlayer cooling assembly is required to be divided into a multi-section structure, each section is brazed and then welded into an integral structure, the structure and the process flow are complex, dozens of procedures such as forging, heat treatment, machining, bulging, brazing, electron beam welding and the like are involved in the forming process, the production period is long, the time consumed by the whole production period is nearly 4 months, and the rapid development of an engine is not facilitated.
Disclosure of Invention
The invention solves the technical problems that: the invention provides a selective laser melting forming and post-processing method for a thin-wall interlayer cooling structure, which can realize integral forming of the thin-wall interlayer cooling structure and has high forming quality and high reliability.
The technical solution of the invention is as follows: a selective laser melting forming and post-processing method for a thin-wall interlayer cooling structure comprises the following steps:
(1) Establishing a three-dimensional model of the thin-wall interlayer cooling structure according to an additive manufacturing technology;
(2) In model processing software, placing the small end of the three-dimensional model established in the step (1) upwards;
(3) Intercepting a local part in the model to perform a forming and post-processing test, and performing iterative optimization on the model according to a liquid flow result to obtain a three-dimensional model of the thin-wall interlayer cooling structure body part;
(4) Adding a shape-following lattice support and an outer wall support of the inner wall of the revolving body according to the three-dimensional model determined in the step (3);
(5) In an inert gas environment, carrying out selective laser melting forming according to the three-dimensional model with the support obtained in the step (4) to obtain a thin-wall interlayer cooling structural member with a substrate and the support;
(6) Cleaning the inner cavity powder of the thin-wall interlayer cooling component with the substrate and the support obtained in the step (5), and performing wax filling protection;
(7) Removing the outer wall support of the thin-wall interlayer cooling structure member protected by wax filling in the step (6) by adopting a mechanical processing and manual polishing method, separating the substrate and the thin-wall interlayer cooling structure member by adopting wire cut electrical discharge machining, removing the inner wall conformal lattice support and the machined end face by adopting mechanical processing, and then carrying out dewaxing treatment;
(8) And (4) carrying out heat treatment and surface finishing on the thin-wall interlayer cooling structure member without the external support obtained in the step (7) to obtain the thin-wall interlayer cooling structure.
The thin-wall interlayer cooling structure comprises an inner wall, an outer wall, a rib wall, an outlet liquid collecting ring and an inlet liquid collecting ring, wherein the outlet liquid collecting ring and the inlet liquid collecting ring are respectively arranged at two ends of the outer wall, the rib wall is positioned between the inner wall and the outer wall, the rib wall is of a straight-through type or a spiral inclination angle type structure, the thicknesses of the inner wall and the outer wall are not more than 5mm, and a cooling channel is a flow channel with the length-diameter ratio exceeding 100.
In the step (1), according to the structural strength and the liquid flow performance of the thin-wall interlayer cooling structure, a connecting structure and a welding line existing in a thin-wall interlayer cooling structure model are eliminated, the additive manufacturing method is modified, the thin-wall interlayer cooling structure is obtained, the STL format three-dimensional model is derived, and the derivation precision is superior to 0.008mm.
The specific method of the step (3) is as follows:
3.1, respectively extracting characteristic local part models at the top, the throat and the bottom of the thin-wall interlayer cooling structure by using modeling software;
step 3.2, modifying the rib width, the rib height and the channel width of the interlayer cooling channel structure in the feature part, and establishing a series of cooling channel size models with the rib width of 1.0-2.5 mm, the rib height of 2.0-4.0 mm and the size of 0.1mm increasing progressively;
step 3.3, carrying out laser selective melting forming on the serial interlayer cooling channel size model to obtain a real object, then polishing the cooling channel by adopting a chemical polishing reagent, and carrying out a liquid flow test under the pressure of 0.5MPa to obtain a structural model meeting the requirements of the liquid flow test and a treatment process parameter after chemical polishing;
step 3.4, measuring the size of the cooling channel after chemical polishing, and obtaining an optimal cooling channel structure size model through mechanical calculation;
and 3.5, modifying the three-dimensional model obtained in the step (1) according to the results of the step 3.3 and the step 3.4 to obtain a final three-dimensional model of the thin-wall interlayer cooling structure body.
In the step (4), the shape-following lattice support of the inner wall of the revolving body is used for preventing the inner wall from deforming, the size of the lattice cell element is linearly changed along with the revolving radius of the inner wall, and the minimum size of the lattice cell element is not less than 2mm; the relation formula of the size of the dot matrix cell and the turning radius is as follows:
L＝R/(ksinα)；
wherein, L is the cell size that the dot matrix supported, R is the radius of gyration of inner wall (2), and k is the constant, and alpha is the contained angle of solid of revolution inner wall along axial tangent line and horizontal plane.
In the step (5), the parameters of selective laser melting and forming are as follows: the laser power is 280-320W, the scanning speed is 800-1100 mm/s, the line spacing is 0.10-0.13 mm, the spot diameter is 90-110 μm, the powder layer thickness is 0.03-0.06 mm, and the phase angle is 67 degrees.
In the step (6), powder cleaning is carried out on the inner cavity of the formed component by adopting 0.6-0.8 Mpa compressed air to match with a multi-axis ultrasonic vibration platform; the wax liquid of the wax comprises 50 percent of paraffin and 50 percent of stearic acid, and the wax filling temperature is 60-70 ℃.
In the step (7), the wire cutting is high-speed reciprocating wire-cut electrical discharge machining, the pulse width is set to be 8-28 mu s, the pulse interval is 112-170 mu s, and the waveform is rectangular pulse;
removing the external support of the revolution surface by adopting lathe machining, and machining the end surface support and the allowance of the component by adopting a milling machine;
the dewaxing method comprises the following steps: firstly, the residual wax liquid is steamed in a dewaxing furnace with the pressure of 0.6 plus or minus 0.05MPa and the temperature of 160-170 ℃, and then the residual wax liquid is blown off by high-temperature steam with the temperature of 100 ℃.
In the step (8), the heat treatment system is as follows:
raising the temperature to 600-700 ℃ within 60min, preserving the heat for 60min, then raising the temperature to 1170 ℃ within 60min, preserving the heat for 2-3h, and inflating and cooling.
In the step (8), the surface finishing method is chemical polishing, the polishing solution is a mixed solution of hydrochloric acid, nitric acid and hydrofluoric acid, the polishing solution flows uniformly in the thin-wall interlayer cooling structure component under the rated pressure of 0.1MPa, and the polishing time is 30-35 min.
Compared with the prior art, the invention has the advantages that:
(1) In the process design, lattice support along with the size of a deformation cell element is added in the cold removal structure of the thin-wall interlayer of the revolving body, so that the structural strength of the thin-wall revolving body is ensured, the revolving body is not easy to deform in the forming and post-treatment machining processes, and the thin-wall base layer cooling component is possible to be formed integrally with high quality and high precision; meanwhile, a special chemical polishing tool is adopted to ensure that polishing liquid flows uniformly in the thin-wall interlayer cooling component, so that the aims of uniform polishing of a high-length-diameter-ratio flow passage and good liquid flow effect are fulfilled, and a key link of the heat exchange functionality of the thin-wall interlayer cooling component is realized.
(2) The invention ensures the structural strength of the rotary thin wall by adding lattice support along with the dimension of the deformation cell element on the inner wall, ensures that the rotary body is not easy to deform in the forming and post-treatment machining processes, ensures the possibility of forming the thin-wall interlayer cooling member in a high-quality, high-precision and integrated manner, and simultaneously ensures the forming quality of the thin-wall interlayer cooling member.
(3) The thin-wall interlayer cooling component is prepared by the existing process, the brazing seam strength is only 50% of the strength of the base material, the reliability is not high, the brazing process is not needed by adopting the material increase manufacturing whole, the problem that the cracking is easily caused by multiple times of vibration in the working process of an engine is avoided, and the reliability is improved.
(4) Compared with the traditional brazing process after machining, the integral forming method adopted by the invention has the advantages that the number of parts is dozens to 1, the machining procedures are reduced, and the production period is shortened from 4 months to 2 weeks.
(5) The invention adopts a chemical polishing method to carry out the finishing processing on the interlayer cooling channel, thereby ensuring that the liquid flow result meets the design index on one hand, solving the problem that the powder in the inner cavity of the interlayer cooling channel with high length-diameter ratio is difficult to remove on the other hand, and ensuring the reliability of the thin-wall interlayer cooling structure component.
Drawings
FIG. 1 is a front view of a thin-walled sandwich cooling member of the present invention.
FIG. 2 is a structural view of an internal flow passage of the thin-walled sandwich cooling member of the present invention.
FIG. 3 is a connection structure diagram of the thin-wall interlayer cooling member and the inner wall lattice support according to the present invention.
FIG. 4 is a parameter diagram of a lattice-supported cell size formula according to the present invention.
FIG. 5 is a schematic view of a lattice support structure according to the present invention.
Reference numerals: 1-outer wall, 2-inner wall, 3-rib wall, 4-outlet liquid collecting ring, 5-inlet liquid collecting ring, 6-inlet and 7-inner wall conformal lattice support.
Detailed Description
The invention is described with reference to the accompanying drawings.
As shown in fig. 1 and 2, the thin-walled sandwich cooling structure of the present invention comprises an inner wall 2, an outer wall 1, a rib wall 3, an outlet liquid collecting ring 4 and an inlet liquid collecting ring 5, wherein the rib wall 3 is located between the inner wall 2 and the outer wall 1 to jointly form a sandwich channel which is a variable cross-section flow channel, and the minimum channel dimension is 1mm × 1mm. The cooling liquid enters the body part through four inlets 6 of the inlet liquid collecting ring 5 and flows in the cooling channel to cool the sandwich structure.
In order to effectively prevent the interlayer from cooling and removing the structural string cavity and improve the working reliability, the optimal forming scheme is to integrally form under the condition of ensuring the dimensional precision and the surface quality requirement of a complex flow path, and based on the method, the application provides a selective laser melting forming and post-processing method for the thin-wall interlayer cooling structure.
Because the existing thin-wall interlayer cooling component is generally formed by assembling and welding after parts are processed in a split mode, part of the structure is not suitable for integral forming, and the structure needs to be modified adaptively, the method comprises the following steps:
(1) Establishing a three-dimensional model of a body part (namely the whole thin-wall interlayer cooling structure) and optimizing:
and establishing a three-dimensional model of the body part by using modeling software UG or Pro/engineer, comprehensively considering a plurality of constraint conditions such as structural strength, liquid flow performance and the like, eliminating a large number of connecting structures and welding seams existing in the body part model, carrying out additive manufacturing adaptability modification to obtain an integral thin-wall interlayer cooling member, and then exporting the STL format three-dimensional model with the exporting precision superior to 0.008mm.
(2) Placing the three-dimensional model established in the step (1) according to the requirements: in order to ensure the accuracy of the subsequent liquid flow process test result, the consistency and the forming stability of the flow channel need to be ensured, and the small end of the thin-wall interlayer cooling component is placed upwards.
(3) The interlayer cooling channel is a unit component determining performance, so that according to the three-dimensional model laid in the step (2), parts of the top, the throat and the bottom in the model are extracted for iterative optimization to determine a final three-dimensional model:
the method for establishing the final model by iterative optimization comprises the following steps:
firstly, respectively extracting feature part models at the top, the throat and the bottom of a body part by using modeling software;
secondly, modifying the size of the interlayer cooling channel in the feature part, wherein the size of the interlayer cooling channel is a main parameter influencing the liquid flow effect, and the main parameter comprises rib width, rib height and channel width, establishing a series of cooling channel size models with the rib width of 0.5mm-1.0mm, the rib height of 2.0mm-4.0mm, the channel width of 1.0mm-2.5mm and the size of increasing 0.1mm, and the specific flow channel size comprises the rib width multiplied by the rib height multiplied by the channel width: 0.5 mm. Times.2.0 mm. Times.1.0 mm, 0.6 mm. Times.2.1 mm. Times.1.1 mm, etc.;
thirdly, carrying out a 'forming-chemical polishing post-treatment-liquid flow' process test on the serial interlayer cooling channel size model to obtain a structure model meeting the requirements of the liquid flow test and chemical polishing post-treatment process parameters;
fourthly, measuring the size of the cooling channel after chemical polishing, comprehensively considering the light weight requirement and the strength requirement of the product, and obtaining an optimal cooling channel structure size model through mechanical calculation;
and fifthly, modifying the three-dimensional model obtained in the step (1) according to the results of the third step and the fourth step, and performing iterative optimization to obtain a final body three-dimensional model.
(4) Because body portion intermediate layer runner is long and narrow, and interior outer wall is thin-walled structure, the support intensity when the solid of revolution takes shape is not enough, and the vibration material disk equipment sets up the outside support when taking shape other products, according to the three-dimensional model that step (3) confirmed and the scheme of putting that step (2) confirmed, adds solid of revolution inner wall and takes shape lattice support and outer wall support:
as shown in fig. 3, 4 and 5, the revolving body conformal lattice support 7 is mainly used for preventing the deformation of the inner wall, the size of lattice cells changes linearly with the revolving radius, and the size of the cells at the throat part is the smallest and is not less than 2mm.
The relation formula of the cell size and the turning radius is as follows:
L＝R/(ksinα)；
wherein, L is the cell size that the dot matrix supported, and R is radius of gyration, and k is the constant, and alpha is the contained angle of solid of revolution inner wall along axial tangent line and horizontal plane.
(5) In an inert gas environment, carrying out selective laser melting forming according to the supported three-dimensional model obtained in the step (4) to obtain an interlayer cooling member with a lattice support and an outer wall support:
specifically, the parameters of selective laser melting forming are as follows: the laser power is 280-320W, the scanning speed is 800-1100 mm/s, the line spacing is 0.10-0.13 mm, the spot diameter is 90-110 μm, the powder layer thickness is 0.03-0.06 mm, and the phase angle is 67 degrees.
(6) Cleaning the inner cavity powder of the thin-wall interlayer cooling component with the substrate and the support obtained in the step (5), and filling wax for protection;
blowing powder from the formed body inner cavity by using 0.6 Mp-0.8 Mpa compressed air and an ultrasonic vibration platform; the wax liquid of the wax filling comprises 50 percent of paraffin and 50 percent of stearic acid, and the wax filling temperature is 60-70 ℃.
(7) Removing the outer wall support of the thin-wall interlayer cooling component protected by wax filling in the step (6) by adopting a mechanical processing and manual polishing method, then separating the substrate and the component by adopting wire cut electrical discharge machining, then removing the inner wall conformal lattice support and the machined end face by adopting mechanical processing, and then carrying out dewaxing treatment:
the wire cutting is high-speed reciprocating wire-cut electrical discharge machining, the pulse width is set to be 8-28 mu s, the pulse interval is 112-170 mu s, the waveform is rectangular pulse, the cutting efficiency is high, the cutting effect is good, and the quality of the formed body part is ensured; removing the external support of the revolution surface by lathe processing, and processing the end surface support and the allowance of the body part by a milling machine; the dewaxing treatment method comprises the following steps: firstly, steaming and removing the wax liquid in a dewaxing furnace with the pressure of 0.6 +/-0.05 MPa and the temperature of 160-170 ℃, and then blowing and removing the residual wax liquid by using high-temperature steam; and removing the external support at the bottom and the lower end of the second layer by adopting lathe machining.
(8) Carrying out heat treatment and surface finishing on the body part with the external support removed obtained in the step (7) to obtain the thin-wall interlayer cooling structure member: the heat treatment system is stabilized treatment, the temperature is increased to 600-700 ℃ within 60min, the temperature is kept for 60min, then the temperature is increased to 1170 ℃ within 60min, the temperature is kept for 2-3h, and the mixture is aerated and cooled; and (4) selecting the surface finishing process according to the step (3), specifically, the surface finishing method is chemical polishing, the polishing solution is a mixed solution of hydrochloric acid, nitric acid, hydrofluoric acid and the like, the polishing solution uniformly flows in the body part under the rated pressure of 1MPa, and the polishing time is 30-35 min.
Those skilled in the art will appreciate that those matters not described in detail in the present specification are not particularly limited to the specific examples described herein.
Claims (7)
1. A selective laser melting forming and post-processing method for a thin-wall interlayer cooling structure is characterized by comprising the following steps:
(1) Establishing a three-dimensional model of the thin-wall interlayer cooling structure according to an additive manufacturing technology;
(2) In model processing software, placing the small end of the three-dimensional model established in the step (1) upwards;
(3) Intercepting a local part in the model to perform a forming and post-processing test, and performing iterative optimization on the model according to a liquid flow result to obtain a three-dimensional model of the thin-wall interlayer cooling structure body part;
the specific method of the step (3) is as follows:
3.1, respectively extracting characteristic local part models at the top, the throat and the bottom of the thin-wall interlayer cooling structure by using modeling software;
step 3.2, modifying the rib width, the rib height and the channel width of the interlayer cooling channel structure in the feature part, and establishing a series of cooling channel size models with the rib width of 1.0-2.5 mm, the rib height of 2.0-4.0 mm and the size of 0.1mm increasing progressively;
step 3.3, carrying out laser selective melting forming on the serial interlayer cooling channel size model to obtain a real object, then polishing the cooling channel by adopting a chemical polishing reagent, and carrying out a liquid flow test under the pressure of 0.5MPa to obtain a structural model meeting the requirements of the liquid flow test and a treatment process parameter after chemical polishing;
step 3.4, measuring the size of the cooling channel after chemical polishing, and obtaining an optimal cooling channel structure size model through mechanical calculation;
step 3.5, modifying the three-dimensional model obtained in the step (1) according to the results of the step 3.3 and the step 3.4 to obtain a final three-dimensional model of the thin-wall interlayer cooling structure body part;
(4) Adding a shape-following lattice support and an outer wall support of the inner wall of the revolving body according to the three-dimensional model determined in the step (3);
in the step (4), the shape-following lattice support of the inner wall of the revolving body is used for preventing the deformation of the inner wall (2), the size of lattice cell elements is linearly changed along with the revolving radius of the inner wall (2), and the minimum size of the lattice cell elements is not less than 2mm; the relation formula of the size of the dot matrix cell and the turning radius is as follows:
L＝R/(ksinα)；
wherein L is the size of a cell supported by the dot matrix, R is the gyration radius of the inner wall (2), k is a constant, and alpha is the included angle between the inner wall of the revolution body and the horizontal plane along the axial tangent line;
(5) In an inert gas environment, carrying out selective laser melting forming according to the three-dimensional model with the support obtained in the step (4) to obtain a thin-wall interlayer cooling structural member with a substrate and the support;
(6) Cleaning the inner cavity powder of the thin-wall interlayer cooling component with the substrate and the support obtained in the step (5), and performing wax filling protection;
(7) Removing the outer wall support of the thin-wall interlayer cooling structure member protected by wax filling in the step (6) by adopting a mechanical processing and manual polishing method, separating the substrate and the thin-wall interlayer cooling structure member by adopting wire cut electrical discharge machining, removing the inner wall conformal lattice support and the machined end face by adopting mechanical processing, and then carrying out dewaxing treatment;
(8) Performing heat treatment and surface finishing on the thin-wall interlayer cooling structure member without the external support obtained in the step (7) to obtain a thin-wall interlayer cooling structure;
in the step (8), the surface finishing method is chemical polishing, the polishing solution is a mixed solution of hydrochloric acid, nitric acid and hydrofluoric acid, the polishing solution flows uniformly in the thin-wall interlayer cooling structure component under the rated pressure of 0.1MPa, and the polishing time is 30-35 min.
2. The selective laser melting forming and post-processing method for the thin-wall interlayer cooling structure according to claim 1, wherein the selective laser melting forming and post-processing method comprises the following steps: thin wall intermediate layer cooling structure include inner wall (2), outer wall (1), rib wall (3), export album of liquid ring (4) and entry album of liquid ring (5), outer wall (1) both ends set up export album of liquid ring (4), entry album of liquid ring (5) respectively, rib wall (3) are in between inner wall (2) and outer wall (1), rib wall (3) are two kinds of structures of through type or spiral inclination formula, the inside and outside wall thickness all is no longer than 5mm, cooling channel is the runner that draw ratio surpasses 100.
3. The selective laser melting forming and post-processing method for the thin-wall interlayer cooling structure according to claim 1 or 2, wherein the selective laser melting forming and post-processing method comprises the following steps: in the step (1), according to the structural strength and the liquid flow performance of the thin-wall interlayer cooling structure, a connecting structure and a welding line existing in a thin-wall interlayer cooling structure model are eliminated, the additive manufacturing method is modified, the thin-wall interlayer cooling structure is obtained, the STL format three-dimensional model is derived, and the derivation precision is superior to 0.008mm.
4. The selective laser melting forming and post-processing method for the thin-wall interlayer cooling structure according to claim 3, wherein the selective laser melting forming and post-processing method comprises the following steps: in the step (5), the parameters of selective laser melting and forming are as follows: the laser power is 280-320W, the scanning speed is 800-1100 mm/s, the line spacing is 0.10-0.13 mm, the spot diameter is 90-110 μm, the powder layer thickness is 0.03-0.06 mm, and the phase angle is 67 degrees.
5. The selective laser melting forming and post-processing method of the thin-wall interlayer cooling structure according to claim 4, wherein the selective laser melting forming and post-processing method comprises the following steps: in the step (6), powder cleaning is carried out on the inner cavity of the formed component by adopting 0.6-0.8 Mpa compressed air to match with a multi-axis ultrasonic vibration platform; the wax liquid of the wax comprises 50 percent of paraffin and 50 percent of stearic acid, and the wax filling temperature is 60-70 ℃.
6. The selective laser melting forming and post-processing method of the thin-wall interlayer cooling structure according to claim 5, wherein the selective laser melting forming and post-processing method comprises the following steps: in the step (7), the wire cutting is high-speed reciprocating wire-cut electrical discharge machining, the pulse width is set to be 8-28 mu s, the pulse interval is 112-170 mu s, and the waveform is rectangular pulse;
removing the external support of the revolution surface by adopting lathe machining, and machining the end surface support and the allowance of the component by adopting a milling machine;
the dewaxing method comprises the following steps: firstly, the residual wax liquid is steamed in a dewaxing furnace with the pressure of 0.6 plus or minus 0.05MPa and the temperature of 160-170 ℃, and then the residual wax liquid is blown off by high-temperature steam with the temperature of 100 ℃.
7. The selective laser melting forming and post-processing method of the thin-wall interlayer cooling structure according to claim 6, wherein: in the step (8), the heat treatment system is as follows:
raising the temperature to 600-700 ℃ within 60min, preserving the heat for 60min, then raising the temperature to 1170 ℃ within 60min, preserving the heat for 2-3h, and inflating and cooling.
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