CN114769596A - Snake bone structure and part preparation method thereof - Google Patents

Snake bone structure and part preparation method thereof Download PDF

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Publication number
CN114769596A
CN114769596A CN202210537278.7A CN202210537278A CN114769596A CN 114769596 A CN114769596 A CN 114769596A CN 202210537278 A CN202210537278 A CN 202210537278A CN 114769596 A CN114769596 A CN 114769596A
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snake bone
degreasing
heating
sintering
powder
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余勇
欧阳豪
王霄
李益民
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Hunan Injection High Technology Co ltd
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Hunan Injection High Technology Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1017—Multiple heating or additional steps
    • B22F3/1021—Removal of binder or filler
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1017—Multiple heating or additional steps
    • B22F3/1021—Removal of binder or filler
    • B22F3/1025—Removal of binder or filler not by heating only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/042—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling using a particular milling fluid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Materials For Medical Uses (AREA)

Abstract

The invention discloses a snake bone structure and a preparation method of parts of the snake bone structure. The preparation process comprises the following steps: dispersing metal powder raw materials, weighing the metal powder raw materials and a binder according to a designed proportion, uniformly mixing to obtain a feed, sequentially carrying out injection molding, powder burying, degreasing, sintering and heat treatment to obtain the component. The snake bone has the positioning structure, so that the assembly is convenient, the assembly precision and efficiency are effectively improved, the preparation method is simple, the production efficiency is high, the cost is low, and the mass production is facilitated.

Description

Snake bone structure and part preparation method thereof
Technical Field
The invention relates to the field of medical equipment, in particular to a snake bone structure and a part preparation method thereof.
Background
The medical endoscope obtains images at different positions and reaches an operation area by bending in a human body, and most of the endoscopes on the market realize the function through a snake bone connected by a plurality of snake bone parts.
In the prior art, the snake bones are mostly prepared by a mechanical processing mode and are connected by adopting a riveting structure, for example, in patent 201510207482.2, preparation method of snake bone device of endoscope, stainless steel pipes are prepared into the snake bones after cutting, leveling, stamping, polishing and other procedures, and the production efficiency is low and the cost is high. It is known that the snake bone is prepared by injection molding to improve the production efficiency and reduce the production cost, for example, the patent '201710985068.3 metal powder injection molding method for processing the snake bone of endoscope' provides a metal injection molding preparation method, but the snake bone connection is still in a riveting form, the riveting process has higher requirement, the quality problem is easy to generate, and the production efficiency is also lower. The prior art '201780086240. X, endoscope bending part' provides a snake bone without a riveting structure, but a positioning device is not provided, and the assembly precision is difficult to guarantee.
In addition, in the using process of the endoscope, in order to reduce the pain of a patient, the inner diameter and the wall thickness of the snake bone are preferably thin, the defects of short injection, breakage, holes and the like are easily generated during injection of the thin wall and the microstructure, and the thin wall and the microstructure are easy to deform after degreasing and sintering, which puts higher requirements on the preparation process.
In view of the above problems, the present invention provides a snake bone structure with no riveting structure and easy assembly, and a method for preparing snake bone with low cost and high efficiency.
Disclosure of Invention
In order to solve the problem of preparation of the existing snake bone, the snake bone structure and the preparation method are provided, and the snake bone structure is provided with a positioning structure and is convenient to assemble; the provided metal injection molding preparation method solves the problems of complex preparation process, high production cost, low efficiency and the like of the snake bone.
In order to achieve the purpose, the invention adopts the following scheme:
the snake bone structure is characterized in that the snake bone structure is provided with two pairs of double grooves and hinge lugs which play a role in positioning and rotating and an operation wire insertion part, and the snake bone part is molded and prepared by adopting a metal injection molding method;
in the snake bone structure, a snake bone part comprises an upper part and a lower part, the upper part is provided with special-shaped grooves which are opposite along the radial direction, the part close to the inner wall of the snake bone part is a plane along the axial direction, the plane is provided with an open slot along the axial direction, the opening shape of the slot can be a rectangle, a trapezoid or a semicircle and the like, the end part of the slot is tangent to an arc, and the size of the open slot does not exceed that of the special-shaped slot; the lower part is provided with a pair of hinge lugs which pass through a central shaft plane and form an included angle of 90 degrees with the upper special-shaped groove, the inner surfaces of the hinge lugs are planes along the axial direction, the central axis is provided with a positioning part, the positioning part can be in the shape of a rectangle, a trapezoid, a semicircle or a circle with a tangent arc at the tail end, and the diameter of the arc or the circle is less than or equal to that of the tangent arc at the end part of an open groove at the upper part of the snake bone; the operation wire insertion part is positioned on the inner wall of the snake bone part and is parallel to the central axis of the part, and the axis of the insertion part and the central line of the central axis of the part, the double grooves or the hinge lugs are positioned on the same plane.
In a preferred embodiment, the preparation method comprises the following preparation steps:
s1, performing dispersion treatment, namely adding 2-5% of oleic acid into spherical or nearly spherical 17-4ph stainless steel pre-alloy powder with the average particle size of 1-10 mu m for ball milling, wherein the ball material ratio is (0.5-1): 1;
s2, mixing materials, namely uniformly mixing the metal powder raw material and the binder;
s3, injection, namely, injection molding the feed material by using an injection molding machine, wherein the injection temperature is 170-180 ℃, and the mold temperature is 100-120 ℃;
s4, burying powder, namely burying the injection blank in alumina powder, and vibrating to fill gaps with the alumina powder;
s5, degreasing, wherein the degreasing process comprises solvent degreasing and thermal degreasing, and the thermal degreasing and sintering are integrated;
s6, thermal dehydration and sintering, namely placing the solvent degreased blank in a sintering furnace for degreasing and sintering;
s7, heat treatment, namely placing the snake bone into a heat treatment furnace for solution treatment and aging treatment.
Preferably, the adhesive comprises the following components in percentage by mass:
30-50% of Paraffin (POM);
30-40% of High Density Polyethylene (HDPE);
10-20% of ethylene-vinyl acetate copolymer (EVA);
10-20% of polypropylene (PP).
In the preferable scheme, the powder loading amount is 50-55% in the material mixing process, namely the metal powder accounts for 50-55% of the total volume, the mixing temperature is 190-200 ℃, and the mixing time is 0.5-1 h.
In the preferable scheme, the solvent in the solvent degreasing is n-heptane, the temperature is 30-40 ℃, and the time is 5-7 h.
In a preferred scheme, the thermal degreasing and sintering integrated process comprises the following steps: vacuumizing, heating to 230-250 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 30-60 min, heating to 300-350 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 60-90 min, heating to 400-450 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 60-90 min, heating to 800-900 ℃ at the speed of 3-10 ℃/min, preserving heat for 20-30 min, heating to 1300-1380 ℃ at the speed of 3-10 ℃/min, preserving heat for 2-3 h, and cooling along with the furnace.
In the preferable scheme, the heat treatment process comprises heating salt bath to 1030-1080 ℃ for solid solution for 2-3 h, and aging at 450-500 ℃ for 4-6 h.
Preferably, the snake bone density is 7.5-7.8 g/cm3。
The principle and the advantages are as follows:
the snake bone structure is high in dimensional precision and convenient to assemble. In the snake bone structure, a hinge lug and a double-groove structure are adopted, and a riveting mode is replaced by a hinge mode for connection. On one hand, the production efficiency and the yield are improved; on the other hand, the double-groove structure and the hinge lug with the positioning part are butted for assembly, so that the positioning between the front snake bone parts and the rear snake bone parts can be realized, the assembly requirement is greatly reduced, the connection between the snake bone parts can be completed without higher proficiency, and the assembly precision is effectively ensured.
The snake bone parts are prepared by a metal injection molding method, and the one-step molding of complex shapes is realized. For example, the hinge lug and double-groove structure for realizing the rotation and positioning functions needs a plurality of working procedures in a machining mode, and is difficult to machine, and the metal injection molding has great freedom degree in the design of complex small parts, and can realize a structure which is difficult to realize by a conventional preparation method. The hinge lug and the double-groove structure for realizing the rotation and positioning functions can be formed at one time without subsequent processing.
Introducing powder dispersion treatment, adding 2-5% of oleic acid for ball milling, and aiming at preventing the occurrence of injection defects caused by nonuniform feeding components due to raw material powder agglomeration by ball milling dispersion agglomerated powder, reducing feeding fluidity and being incapable of effectively filling a die, wherein the oleic acid is attached to the powder surface and can prevent subsequent agglomeration; furthermore, the adsorption of the acid on the surface of the powder facilitates the binding with other organic binders during the subsequent mixing process. In the components of the binder, the paraffin content is low, and the contents of other components including HDPE, EVA and PP are relatively high, so that the strength and shape retention of a green body are improved, the dissolution deformation is avoided, and the fracture of a microstructure in the injection demolding process is prevented. The purpose of adopting higher injection temperature and mold temperature is to improve the fluidity of the feeding material so as to avoid the defects of short injection, holes and the like caused by early solidification due to rapid loss of heat in the injection process. The injection blank is subjected to powder embedding treatment before dissolution, and deformation in the degreasing and sintering processes is prevented by utilizing the supporting effect of the alumina powder. The heating rate in the thermal degreasing process is low, and the temperature is kept in a segmented manner, so that HDPE, EVA and PP are removed in a graded manner, and thermal degreasing deformation is prevented.
Drawings
FIG. 1 is an explanatory view of a snake bone part
FIG. 2 is a front view of a snake bone part
FIG. 3 is a plan view of the snake bone part
FIG. 4 is a view showing the fitting of snake bone
FIG. 5 is a schematic view of the snake bone connection bending
FIG. 6 is a schematic view of a deformed snake bone part 1
FIG. 7 is a schematic view of a deformed snake bone part 2
Detailed Description
Embodiments of the present invention are described below with reference to the drawings. The drawings are schematic nature pictures, the thickness and the proportion are different from the actual ones, and are only for explaining the product features, and there are portions different from each other in the dimensional relationship and the proportion between the drawings.
Example 1
A snake bone structure and a method for preparing parts thereof are disclosed, wherein the snake bone structure is provided with two pairs of double grooves 1a and hinge lugs 1b which play a role in positioning and rotating and an operating wire insertion part 1c as shown in figure 1. In the snake bone structure, a snake bone part comprises an upper part and a lower part, the upper part is provided with special-shaped grooves 1a1 which are opposite along the radial direction, the part close to the inner wall of the snake bone part is a plane along the axial direction, the plane is provided with an open slot 1a2 along the axial direction, the opening shape of the slot can be rectangular, the end part is an arc which is tangent with the slot, the size of the open slot does not exceed that of the special-shaped slot, and the radius of the arc 1a2 is smaller than that of the arc in the special- shaped groove 1a 1; the lower part is provided with a pair of hinge lugs 1b which pass through a central shaft plane and form an included angle of 90 degrees with the upper special-shaped groove, the inner surfaces 1b1 of the hinge lugs are planes along the axial direction, the central axis is provided with a positioning part 1b2, the shape of the positioning part 1b2 can be circular, and the diameter of the circle is less than or equal to the tangent arc of the end part of the upper opening groove 1a2 of the snake bone; the operation wire insertion part 1c is located on the inner wall of the snake bone part and is parallel to the central axis of the part, and the axis of the insertion part and the central line of the central axis of the part and the central lines of the double grooves or the hinge lugs are located on the same plane.
The preparation process comprises the following steps:
dispersing raw materials: adding 3% of oleic acid into spherical or nearly spherical 17-4ph stainless steel pre-alloy powder with the average particle size of 4 mu m for ball milling treatment, wherein the ball-to-material ratio is 0.5: 1.
B, mixing materials: mixing 50% of binder at 190 ℃ for 1h, wherein the binder comprises 40% of Paraffin (POM), 30% of High Density Polyethylene (HDPE), 20% of ethylene-vinyl acetate copolymer (EVA) and 20% of polypropylene (PP).
C, injection: the resulting feedstock was injected using a molding machine at 170 ℃ and 110 ℃.
D, powder burying: the injection blank was embedded in alumina powder and shaken to fill the gaps with alumina powder.
E, solvent degreasing: degreasing for 6h in 40 ℃ n-heptane solution.
F, thermal degreasing and sintering: the thermal degreasing and sintering are carried out simultaneously, and the process comprises the following steps: vacuumizing, heating to 250 deg.C at 1.5 deg.C/min, maintaining for 60min, heating to 320 deg.C at 1.5 deg.C/min, maintaining for 60min, heating to 450 deg.C at 1.5 deg.C/min, maintaining for 90min, heating to 900 deg.C at 8 deg.C/min, maintaining for 20min, heating to 1380 deg.C at 8 deg.C/min, maintaining for 2h, and furnace cooling.
G, heat treatment: the sintered part is subjected to solid solution and aging treatment, specifically, salt bath heating is carried out for 2 hours at 1050 ℃, aging is carried out for 4 hours at 480 ℃, and the density of the part obtained after cooling is 7.8g/cm3。
H, assembling: as shown in figure 4, the assembly mode is that the hinge lug and the double grooves of the two parts are mutually matched, the hinge lug 2b of the No. 2 snake bone part is directly inserted into the No. 1 double groove 1a along the axial direction during assembly, the radial position of the front and rear connecting snake bone part is determined by the surface of the inner groove of the double groove, the rotation or dislocation along the shaft is prevented during assembly, the rotation of the snake bones at a certain angle is ensured by the inner groove 1a2 of the No. 1 double groove and the positioning device 2b2 on the hinge lug, and the snake bone is rotated by controlling an operating line during operation, such as the operating line shown in figure 5 and not shown in the figure.
Example 2
A snake bone structure and a method for preparing parts thereof are disclosed, wherein the snake bone structure is provided with two pairs of double grooves and hinge lugs which play a role in positioning and rotating, and an operation wire insertion part as shown in figure 6. In the snake bone structure, a snake bone part is divided into an upper part and a lower part, the upper part is provided with special-shaped grooves which are opposite along the radial direction, the part close to the inner wall of the snake bone part is a plane along the axial direction, an open slot along the axial direction is arranged on the plane, the shape of the open slot can be trapezoidal, the end part of the open slot is an arc tangent to the open slot, the size of the open slot does not exceed that of the special-shaped slot, and the radius of the arc is smaller than that of the arc in the special-shaped grooves; the lower part is provided with a pair of hinge lugs which pass through a central shaft plane and form an included angle of 90 degrees with the upper special-shaped groove, the inner surfaces of the hinge lugs are planes along the axial direction, the central axis is provided with a positioning part, the positioning part is in a trapezoid shape with a tangent arc at the tail end, and the diameter of the arc is smaller than or equal to that of a tangent arc at the end part of an open groove at the upper part of the snake bone; the operation wire insertion part is positioned on the inner wall of the snake bone part and is parallel to the central axis of the part, and the axis of the insertion part and the central line of the central axis of the part, the double grooves or the hinge lugs are positioned on the same plane.
The preparation process comprises the following steps:
a, raw material dispersion treatment: adding 4% of oleic acid into spherical or nearly spherical 17-4ph stainless steel pre-alloy powder with the average particle size of 4 mu m for ball milling treatment, wherein the ball-to-material ratio is 0.7: 1.
B, mixing materials: mixing the binder at 55% loading capacity at 190 deg.C for 1h, wherein the binder comprises Paraffin (POM) 40%, High Density Polyethylene (HDPE) 30%, ethylene-vinyl acetate copolymer (EVA) 20%, and polypropylene (PP) 20%.
C, injection: the resulting feedstock was injected using a molding machine at 175 ℃ and 100 ℃ mold temperature.
D, powder burying: the injection blank was embedded in alumina powder and shaken to fill the gaps with alumina powder.
E, solvent degreasing: degreasing for 6h in 40 ℃ n-heptane solution.
F, thermal degreasing and sintering: the thermal degreasing and sintering are carried out simultaneously, and the process comprises the following steps: vacuumizing, heating to 250 deg.C at 1.5 deg.C/min, maintaining for 60min, heating to 320 deg.C at 1.5 deg.C/min, maintaining for 60min, heating to 450 deg.C at 1.5 deg.C/min, maintaining for 90min, heating to 900 deg.C at 8 deg.C/min, maintaining for 20min, heating to 1350 deg.C at 8 deg.C/min, maintaining for 2h, and furnace cooling.
G, heat treatment: the sintered part is subjected to solid solution and aging treatment, specifically salt bath heating to 1080 ℃ for solid solution for 2h, 500 ℃ for aging for 4h, and the density of the part obtained after cooling is 7.6g/cm3。
H, assembling: the assembly mode is as shown in fig. 4, when in assembly, the hinge lug 2b of No. 2 snake bone part is directly inserted into the No. 1 double groove 1a along the axial direction, the inner groove surface of the double groove determines the radial position of the front and back connection snake bone part, the rotation or dislocation along the shaft is prevented when in assembly, the inner groove 1a2 of the No. 1 double groove and the positioning device 2b2 on the hinge lug ensure that the snake bone can rotate at a certain angle, and when in operation, the snake bone is rotated by controlling an operating wire, as shown in the assembly fig. 5, the operating wire is not shown in the figure.
Example 3
A snake bone structure and a method for preparing parts thereof are disclosed, wherein the snake bone structure is provided with two pairs of double grooves and hinge lugs which play a role in positioning and rotating, and an operation wire insertion part as shown in figure 7. In the snake bone structure, a snake bone part comprises an upper part and a lower part, the upper part is provided with special-shaped grooves opposite in the radial direction, a part close to the inner wall of the snake bone part is a plane along the axial direction, the plane is provided with an open slot along the axial direction, the opening shape of the slot can be a semicircle, the size of the open slot does not exceed that of the special-shaped slot, and the radius of an arc is smaller than that of an arc in the special-shaped groove; the lower part is provided with a pair of hinge lugs which pass through a central shaft plane and form an included angle of 90 degrees with the upper special-shaped groove, the inner surfaces of the hinge lugs are planes along the axial direction, the central axis is provided with a positioning part, the positioning part is in a semicircle shape, and the diameter of the arc is smaller than or equal to that of the arc tangent to the end part of the open groove at the upper part of the snake bone; the operation wire insertion part is positioned on the inner wall of the snake bone part and is parallel to the central axis of the part, and the axis of the insertion part and the central line of the central axis of the part and the central lines of the double grooves or the hinge lugs are positioned on the same plane.
The preparation process comprises the following steps:
a, raw material dispersion treatment: adding 4% of oleic acid into spherical or nearly spherical 17-4ph stainless steel pre-alloy powder with the average grain diameter of 8.3 mu m for ball milling treatment, wherein the ball-to-material ratio is 1: 1.
B, preparation of feed: mixing 50% of binder at 190 ℃ for 1h, wherein the binder comprises 30% of Paraffin (POM), 40% of High Density Polyethylene (HDPE), 20% of ethylene-vinyl acetate copolymer (EVA) and 20% of polypropylene (PP).
C, injection: the resulting feedstock was injected using a molding machine at 170 ℃ and 120 ℃ mold temperature.
D, powder burying: the injection blank was embedded in alumina powder and shaken to fill the gaps with alumina powder.
E, solvent degreasing: degreasing for 5h in 40 ℃ n-heptane solution.
F, thermal degreasing and sintering: the thermal degreasing and sintering are carried out simultaneously, and the process comprises the following steps: vacuumizing, heating to 250 ℃ at a speed of 1.5 ℃/min, preserving heat for 60min, heating to 320 ℃ at a speed of 1.5 ℃/min, preserving heat for 60min, heating to 450 ℃ at a speed of 1.5 ℃/min, preserving heat for 90min, heating to 900 ℃ at a speed of 8 ℃/min, preserving heat for 20min, heating to 1300 ℃ at a speed of 8 ℃/min, preserving heat for 2h, and cooling along with the furnace.
G, heat treatment: carrying out solid solution and aging treatment on the sintered part, specifically heating the part to 1030 ℃ by a salt bath for solid solution for 2h, aging the part for 5h at 450 ℃, and cooling the part to obtain the part with the density of 7.5g/cm3。
H, assembling: the assembly mode is as shown in fig. 4, when in assembly, the hinge lug 2b of No. 2 snake bone part is directly inserted into the No. 1 double groove 1a along the axial direction, the inner groove surface of the double groove determines the radial position of the front and back connection snake bone part, the rotation or dislocation along the shaft is prevented when in assembly, the inner groove 1a2 of the No. 1 double groove and the positioning device 2b2 on the hinge lug ensure that the snake bone can rotate at a certain angle, and when in operation, the snake bone is rotated by controlling an operating wire, as shown in the assembly fig. 5, the operating wire is not shown in the figure.
Comparative example 1
This comparative example employed substantially the same procedure as in example 1, except that the raw material powder was not subjected to dispersion treatment, micropores appeared on the surface of the final product, and the density was 7.3g/cm3。
Comparative example 2
This comparative example employed substantially the same procedure as in example 1, except for the injection temperature and the mold temperature, and the results are shown below:
serial number Injection temperature/. degree.C Mold temperature/. degree.C Results
1 170 60 Short notes
2 170 130 Internal air hole
3 150 100 Short injection
4 190 100 Producing flash and internal porosity
Comparative example 3
This comparative example employed substantially the same procedure as in example 1, except that the powder burying treatment was not conducted, resulting in exfoliation and deformation at the thin wall after sintering.
Comparative example 4
This comparative example used a method substantially the same as example 1, except that the binder had a higher paraffin wax content, specifically: 60% of paraffin wax (POM); 20% of High Density Polyethylene (HDPE); 10% of ethylene-vinyl acetate copolymer (EVA); polypropylene (PP) 10%, with the result that deformation occurred at the thin wall after solvent degreasing.
The above-described embodiments are merely exemplary embodiments of the present invention, which should not be construed as limiting the scope of the invention, but rather as indicating any equivalent variations, modifications, substitutions and combinations of parts within the spirit and scope of the invention.

Claims (8)

1. A snake bone structure is characterized in that the snake bone structure is provided with two pairs of double grooves and hinge lugs which play a role in positioning and rotating, and an operating wire insertion part;
in the snake bone structure, a snake bone part comprises an upper part and a lower part, the upper part is provided with a plane passing through a central shaft and special-shaped grooves opposite along the radial direction, the part, close to the inner wall of the snake bone part, of the snake bone part is a plane along the axial direction, the plane is provided with an open slot along the axial direction, the opening shape of the slot can be a rectangle, a trapezoid or a semicircle with the end part being tangent to an arc, and the size of the open slot does not exceed that of the special-shaped slot; the lower part is provided with a pair of hinge lugs which pass through a central shaft plane and form an included angle of 90 degrees with the upper special-shaped groove, the inner surfaces of the hinge lugs are planes along the axial direction, a positioning part is arranged on the line, the shape of the positioning part can be rectangular, trapezoidal, semicircular or circular and the like, the tail end of the positioning part is provided with a tangent arc, and the diameter of the arc or the circle is smaller than or equal to that of the tangent arc at the end part of an open slot at the upper part of the snake bone; the operation wire insertion part is positioned on the inner wall of the snake bone part and is parallel to the central axis of the part, and the axis of the insertion part and the central line of the central axis of the part, the double grooves or the hinge lugs are positioned on the same plane.
2. The preparation method of the snake bone part is characterized by comprising the following preparation steps:
s1, performing dispersion treatment, namely adding 2-5% of oleic acid into spherical or nearly spherical 17-4ph stainless steel pre-alloy powder with the average particle size of 1-10 mu m for ball milling, wherein the ball material ratio is (0.5-1): 1;
s2, mixing, namely uniformly mixing the metal powder raw material and the binder;
s3, injection, wherein the feed is injected and molded by an injection molding machine, the injection temperature is 170-180 ℃, and the mold temperature is 100-120 ℃;
s4, embedding powder, namely embedding the injection blank into alumina powder, and vibrating to fill the alumina powder into gaps;
s5, degreasing, wherein the degreasing process comprises solvent degreasing and thermal degreasing, and the thermal degreasing and sintering are integrated;
s6, thermal degreasing and sintering, namely placing the solvent degreased blank in a sintering furnace for thermal degreasing and sintering;
s7, heat treatment, namely placing the snake bone into a heat treatment furnace for solid solution and aging treatment.
3. The method for manufacturing a snake bone part according to claim 2, wherein the chemical mass ratio of the components of the binder is as follows:
30-50% of Paraffin (POM);
30-40% of High Density Polyethylene (HDPE);
10-20% of ethylene-vinyl acetate copolymer (EVA);
10-20% of polypropylene (PP).
4. The method for preparing a snake bone part according to claim 2, wherein the powder loading amount in the mixing process is 50-55%, i.e. the metal powder accounts for 50-55% of the total volume, the mixing temperature is 190-200 ℃, and the mixing time is 0.5-1 h.
5. The method for manufacturing a snake bone part according to claim 2, wherein the solvent used in the solvent degreasing is n-heptane, the temperature is 30-40 ℃, and the time is 5-7 h.
6. The method for preparing a snake bone part according to claim 2, which is characterized in that the thermal degreasing and sintering integrated process comprises the following steps: vacuumizing, heating to 230-250 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 30-60 min, heating to 300-350 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 60-90 min, heating to 400-450 ℃ at the speed of 1.5-3 ℃/min, preserving heat for 60-90 min, heating to 800-900 ℃ at the speed of 3-10 ℃/min, preserving heat for 20-30 min, heating to 1300-1380 ℃ at the speed of 3-10 ℃/min, preserving heat for 2-3 h, and cooling along with the furnace.
7. The method for preparing a snake bone part according to claim 2, wherein the heat treatment process comprises heating the snake bone part in a salt bath to 1030-1080 ℃ for solid solution for 2-3 h, and aging at 450-500 ℃ for 4-6 h.
8. A snake bone according to any one of claims 1 to 7, which has a density of 7.5 to 7.8g/cm3。
CN202210537278.7A 2022-05-17 2022-05-17 Snake bone structure and part preparation method thereof Pending CN114769596A (en)

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CN202210537278.7A CN114769596A (en) 2022-05-17 2022-05-17 Snake bone structure and part preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210537278.7A CN114769596A (en) 2022-05-17 2022-05-17 Snake bone structure and part preparation method thereof

Publications (1)

Publication Number Publication Date
CN114769596A true CN114769596A (en) 2022-07-22

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