CN112902744A

CN112902744A - Rocket launching tube bracket and integrated rapid forming method thereof

Info

Publication number: CN112902744A
Application number: CN202110192565.4A
Authority: CN
Inventors: 韩志杰; 黄风山; 刘晓阳; 满晓飞; 霍增辉
Original assignee: Hebei University of Science and Technology
Current assignee: Hebei University of Science and Technology
Priority date: 2021-02-20
Filing date: 2021-02-20
Publication date: 2021-06-04
Anticipated expiration: 2041-02-20
Also published as: CN112902744B

Abstract

The invention discloses a rocket launcher bracket and an integrated rapid forming method thereof. The rapid integrated forming processing is realized through scanning and preprocessing of bracket parts, three-dimensional model reconstruction, metal 3D printing and finish machining of 3D printed parts. The bracket can realize the quick fixation of the rocket tube, the adjustment range of the shooting range is large, the overall stability is good, the quick forming method of the bracket can avoid the problems of overlarge deformation of the welding part of the bracket and the like, the interface bonding strength and the matching precision can be effectively improved, and the dead weight of the bracket is greatly reduced on the premise of ensuring the overall strength.

Description

Rocket launching tube bracket and integrated rapid forming method thereof

Technical Field

The invention relates to auxiliary supporting equipment in a rocket launching device and a preparation method for quick forming of the auxiliary supporting equipment, in particular to a rocket launching tube bracket and an integrated quick forming method of the rocket launching tube bracket.

Background

The existing rocket launcher mainly comprises a launching tube, a protective shell, a front protective cover, a rear protective cover, a launching mechanism, a firing mechanism, an aiming device, a handle, braces and the like, wherein the launching tube is of a sleeve type structure, the front tube is made of glass fiber reinforced plastic materials, and the rear tube is made of aluminum products. The launching tube is fixed on the frame and is wound by a protective belt to form an integral protective shell. The auxiliary support is arranged below the integral protective shell and comprises a tripod and a bracket, the auxiliary support is used for supporting and positioning the emitter barrel, the integral balance of the whole device is guaranteed when the rocket projectile is emitted, and the angle of the barrel can be adjusted.

At present, because a rocket tube is a portable antitank weapon for launching rocket projectiles, the reaction time of easy fire control is required to be less than 10 seconds, the directional shooting range is 360 degrees, and the high-low shooting range is-6 degrees to 30 degrees. The bracket on the rocket launcher is generally in a U-shaped welding structure, the lower end of the bracket is provided with a base connected with a tripod, the upper end of the bracket is a U-shaped support, and the support connecting section is connected with the rocket launcher through a pin. Because the shape of horse shoe-shaped bracket is the welding piece of high strength steel, the shape is more complicated, and the machined surface is more, and the quality is big, can not satisfy the requirement of field equipment lightweight, because welding heat input is too high and electric arc pressure is great, leads to its shaping quality poor, and the shaping precision is lower, and the welding piece after the cooling can produce the deformation, and the welding seam is difficult fully to contact in addition, influences the cooperation precision between whole bracket and the rocket tube, hardly guarantees requirements such as high accuracy location and quick adjustment.

In addition, due to the problems of precision processing and the like, the fork frame type part similar to a rocket launcher bracket is generally prepared by adopting a 3D metal printing technology to realize integrated molding. The reinforcing ribs, the fixing plates or the connecting frames with different thicknesses and shapes can be integrally formed with the integral shape of the part in the integral forming process, the limitations of the traditional processes such as casting forming, extrusion forming and welding forming are greatly broken through by the shape, the thickness, the strength and the like of the formed part, and therefore the connecting part or the welding area can be prevented from becoming a weak link of the integral structure. However, for parts with complex structures, the parts are designed for traditional manufacturing, and in the reverse modeling process, a connection part or a welding area exists to influence the molding quality of the printed parts, so that the reversely constructed model cannot be directly used for 3D metal printing. In the prior art, the precision of metal parts prepared by a 3D printing technology is not more than 0.1mm, so that the rocket launcher bracket parts prepared by the existing 3D printing technology can not reach application indexes.

Disclosure of Invention

The invention aims to solve the technical problem of providing a rocket launcher bracket and an integrated rapid forming method thereof, wherein the bracket can realize rapid fixation of a rocket launcher, has a large adjustment range of shooting range and good overall stability, can avoid the problems of overlarge deformation of a bracket welding part and the like, can effectively improve the interface bonding strength and matching precision, and greatly reduces the self weight of the bracket on the premise of ensuring the overall strength.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a rocket launch canister carriage, characterized in that: the support device comprises a fixed seat and two arc-shaped support arms, wherein the fixed seat is horizontally arranged, the sections of the support arms are groove-shaped plates, one ends of the two support arms are connected with two side surfaces of the left end of the fixed seat to form a semicircular surrounding structure, the other ends of the support arms are provided with semi-open connecting ends, and lightening holes are distributed in the support arms; the middle part of the fixed seat is provided with a positioning boss, the center of the positioning boss is provided with a positioning pin hole, one side of the positioning boss is provided with a connecting boss integrated with the fixed seat, and the center of the connecting boss is provided with a threaded hole for connection; two parallel thread fixing frames are fixed at the right end of the fixing seat, the end parts of the thread fixing frames are round columns, and the centers of the round columns are threaded holes.

Further explaining the scheme, a through hole is formed in the middle of the connecting end, a sliding groove communicated with the through hole is formed in the upper end face of the connecting end, and a 30-degree chamfer is machined at the edge of the sliding groove.

The integrated rapid forming method of the rocket launching tube bracket is characterized by comprising the following steps:

step 1, scanning and preprocessing bracket parts: placing the bracket on a horizontally placed platform to perform scanning more than twice to obtain a plurality of groups of point cloud data of the bracket; respectively importing each group of point cloud data into a Geomagic Wrap platform to obtain a plurality of point cloud models, respectively selecting points at positions corresponding to brackets on the point cloud models as characteristic points, merging the characteristic points, and integrating the characteristic points into a bracket surface patch model; performing completion, finishing and rounding treatment on the bracket dough sheet model;

step 2, bracket three-dimensional model reconstruction: guiding the surface patch model of the bracket into a Geomagic Design X platform, and aligning the coordinate system of the model with the coordinate system of the Geomagic Design X platform; constructing a reference plane of the solid model on the surface patch model of the bracket, and realizing reverse construction of the CAD model based on the reference plane; then, checking the contact ratio of the CAD model and the surface patch model, simultaneously carrying out strength and quality analysis on the CAD model, and carrying out high-precision characteristic processing on the bracket CAD model meeting the requirements to obtain a bracket printing model;

step 3, 3D printing of the bracket: adjusting the internal environment and printing parameters of the metal 3D printer, setting the printing model in a layered mode and simulating printing; after no problem is detected, printing is started to obtain a titanium-based alloy piece of the bracket;

and 4, finishing the 3D printed piece: and carrying out surface treatment on the bracket part obtained by 3D printing by using a polishing tool, and carrying out finish machining on the high-precision characteristic of the bracket formed by printing to finally obtain the bracket part with the same structure as the original model.

Step 2, in the reconstruction process, removing irregular surface patches from the welding part between the fixed seat and the supporting arm of the bracket, and adding the regular characteristic of chamfering; for the surface of the supporting arm of the bracket, a solid model is formed by offsetting based on a large number of sampling points and a component standard curved surface.

In the step 2, the bracket CAD model carries out a high-precision characteristic processing principle: and deleting holes or threaded holes with the diameter less than 8mm on the CAD model of the bracket, reducing the hole diameter of the holes with the diameter more than or equal to 8mm, increasing the hole diameter of the holes with the diameter more than or equal to 1mm along the normal direction for the position of a large machined surface, filling the features of the small machined surface, and removing the features of the position.

The metal 3D printer adopts laser melting printing equipment of SLM forming technology.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

(1) the rocket launching tube bracket adopts a semicircular surrounding structure to fixedly support the launching tube, and adopts a sliding groove structure at the connecting position, so that the launching tube and the bracket can be conveniently and quickly disassembled and assembled, and the rocket launching tube bracket is convenient for field use;

(2) the lower part of the rocket launching tube bracket is designed into a positioning boss and a connecting boss, so that the rocket launching tube bracket and the triangular bracket can be quickly positioned and connected through pins, the quick disassembly and assembly in the field are facilitated, the matching surfaces are two circular planes, the positioning is stable and does not shake, and the overall stability of the rocket launching tube after installation is ensured;

(3) rocket launcher bracket integration rapid prototyping method, very big reduction product production cycle, adopt titanium base alloy material to carry out 3D printing, can easily prepare the part that has hollow or lattice structure, compare original high strength steel and traditional design processing mode and compare, the use quantity of connecting piece has been reduced by a wide margin under the condition of guaranteeing mechanical properties, realize the optimization of part overall dimension and shape, size miniaturization and self weight reduce by a wide margin, can provide bigger space for the installation of functional part, help the bracket to be applied to the rocket launcher, the portability requirement of using in the field.

Drawings

FIG. 1 is an exploded view of the structural components of the bracket;

FIGS. 2 and 3 are schematic views of the welded bracket structure;

FIG. 4 is a schematic view of the connecting end of the bracket;

FIG. 5 is a flowchart of the integrated forming of the bracket;

in the figure: 1. the connecting end 2, the supporting arm 3, the fixing seat 4, the positioning boss 5, the thread fixing frame 6, the connecting boss 7, the lightening hole 11, the chamfer 12, the sliding groove 13 and the pin hole.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

As shown in the attached figure 1, the rocket launcher bracket is formed by welding a fixed

seat

3 and 2 arc-shaped supporting arms 2 which are horizontally arranged, wherein the 2 arc-shaped supporting arms 2 are respectively positioned at two sides of the fixed seat 3 and are integrally formed with the fixed seat, the 2 arc-shaped supporting arms 2 form a semicircular enclosing structure, the open ends of the two supporting arms 2 are provided with connecting ends 1, the connecting ends 1 are connected with pins symmetrically fixed on the outer wall of the rocket launcher, and the semi-enclosing parts of the supporting arms 2 contain the outer circular surface of the rocket launcher to form connection and support for the rocket launcher.

In order to enable the bracket to meet the use and strength requirements of the rocket launching tube and reduce the overall weight of the bracket, as can be seen from figures 1 and 2, the supporting part of the supporting arm 2 is processed into a plate shape by high-strength alloy steel, the end surface of the supporting arm is of a groove-shaped structure, and a plurality of lightening holes 7 are distributed in the middle of the supporting arm 2; the fixing seat 3 is of a frame structure formed by connecting two reinforcing plates in the middle of two vertically-arranged flat plates, the middle of the lower surface of each reinforcing plate is symmetrically provided with a positioning boss 4 and a connecting boss 6, the center of each positioning boss 4 is provided with a positioning pin hole, and the center of each connecting boss 6 is provided with a threaded hole for connection. The positioning boss 4 and the connecting boss 6 are cylindrical structures, and the end surfaces of the positioning boss and the connecting boss are processing surfaces and are positioned on the same plane; two parallel thread fixing frames 5 are fixed at the right end of the fixing seat 3, the end parts of the thread fixing frames 5 are round columns, and the centers of the round columns are threaded holes;

in order to ensure smooth connection between the bracket and pins of a rocket launching tube and facilitate on-site disassembly and assembly, a through hole is formed in the middle of the connecting end 1, a sliding groove 12 communicated with the through hole is formed in the upper end face of the connecting end 1, and 30-degree chamfers are formed in the edges of the sliding groove 12. The pins are elastic and slide into the through holes along the chamfer angles by being aligned with the sliding grooves 12, so that the assembly of the rocket launching tube is completed.

Due to the particularity of application conditions, the bracket disclosed by the invention needs to meet the requirement of light weight of field equipment to the greatest extent besides meeting the requirements of strength and use, so that the aspects of processing mode, material quality, precision and the like of the bracket are improved, and an integrated forming scheme of the bracket is formed. The integrated rapid forming step of the bracket is divided into four stages:

the first stage is as follows: carrier part scanning and preprocessing

(1) Model scanning: the carriage is placed on a horizontally placed platform for scanning. The method comprises the steps of firstly, attaching the surface a of a bracket to a platform, utilizing a handheld three-dimensional optical scanner to conduct 360-degree all-dimensional scanning around and above the bracket, then attaching the surface b to the platform, conducting secondary scanning, and obtaining two point cloud data of the bracket. Before scanning, pre-scanning is required to be carried out, the scanning effect is ensured, the scanner is moved at a constant speed in the scanning process, and the scanning result is checked. In the scanning process, the scanning device rotates around the outer part of the bracket, the data of the outer surface of the scanning result is complete, and the data of the inner side surface of the hole or the groove in the bracket part are not complete, so that the data of the edge part of the hole or the groove in the bracket needs to be checked, the edge structure is required to be clear, and the subsequent model processing is facilitated.

(2) Point cloud data merging: and respectively importing the two scanned point cloud data into a Geomagic Wrap platform to obtain two point cloud models, respectively selecting points at the corresponding positions of the brackets on the point cloud models, taking the points as characteristic points, and merging the points. The feature points are typically selected on the machined surface. On the bracket, the vertexes of four corners of the upper surface of the connecting end 1 and the edge points of the lower surface of the positioning boss 4 are selected as characteristic points. And combining the two point cloud models through the superposition of the characteristic points to form a bracket surface patch model.

(3) Processing of the patch model: completing the incomplete part of the inner surface of the hole or the groove in the bracket dough sheet model to make the inner side wall of the hole or the groove be a complete dough sheet; and smoothing and polishing are carried out on all surface patch data in the bracket surface patch model, so that the surface of the bracket model is smoother, and the arc transition part is more mellow and more close to the surface structure requirement of an actual part. And finally, exporting a bracket patch model as an asc format file by a Geomagic Wrap platform.

And a second stage: three-dimensional model reconstruction of a carrier

(1) And (3) coordinate system alignment: and importing the asc format file of the patch model of the bracket into a Geomagic Design X platform, and adjusting the direction of the bracket model to align the reference plane with the coordinate system in the Geomagic Design X platform. Generally, the a-plane of the carriage model is set as a reference plane, and the position of the plane is manually adjusted so as to coincide with the XOY plane of the stage.

(2) Model reconstruction: necessary fields are divided for the patch model of the bracket to form a reference plane for constructing the solid model. Based on the reference surface, a sketch graph is formed by using sampling points, and a CAD model is reversely constructed by using modeling commands in a platform, such as basic commands of stretching, rotating, lofting, scanning and the like.

In the reconstruction process, removing irregular surface patches and increasing the rule characteristics such as chamfer and the like at the welding part between the fixed seat and the supporting arm of the bracket; the irregular curved surface part of the bracket, such as the surface of the supporting arm, needs to be offset to form a solid model based on a large number of sampling points and the standard curved surface of the component.

(3) Model checking: checking the contact ratio of the CAD model and the surface patch model, requiring the surface offset error of the two models to be within 3%, if the error is too large, repeating the step (2), correcting the models, and finally forming the corrected CAD model.

(4) And analyzing the strength and quality of the CAD model, and judging whether the CAD model meets the design requirements. If the design requirements are not met, the support model is reprocessed according to the analysis structure, and analysis is repeated until the design requirements are met.

(5) Model processing: carry out high accuracy feature processing to satisfying intensity bracket CAD model, mainly handle little structure on the bracket or the position that later stage needs processing, avoid not satisfying the assembly requirement because of 3D prints part surface structure requirement. The treatment principle is as follows: and deleting holes or threaded holes with the diameter less than 8mm on the CAD model of the bracket, reducing the hole diameter of the holes with the diameter more than or equal to 8mm, increasing the hole diameter of the holes with the diameter more than or equal to 1mm along the normal direction for the position of a large machined surface, filling the features of the small machined surface, and removing the features of the position.

For example: removing a sliding groove 12 and a chamfer 11 at the connecting end in the bracket model to enable the side surface of the connecting end to be a plane, and reducing the diameter of a pin hole 13 at the position by 1-2 mm; extending the end face of the positioning boss 4 and the end face of the connecting boss 6, namely the a face to be processed, so that the height is 1mm higher than that of the model, and the aperture of the positioning hole in the center of the positioning boss 4 is reduced by 1-2 mm; and removing the internal thread of the threaded hole at the threaded fixing frame 5, and reducing the aperture by 1 mm.

(6) And exporting the processed bracket CAD model into a file in stl format on a Geomagic Design X platform to obtain a bracket printing model.

And a third stage: bracket 3D printing

(1) Before printing, a dried plane copper substrate is fixed on an internal working platform of the metal 3D printer, the substrate is preheated, titanium-based alloy powder is put into a powder feeder, the feeding and distributing speed is adjusted to be 18g/min, and the collecting effect of powder flow and laser beams is guaranteed. Argon gas environment is arranged in the forming bin, the oxygen content threshold value is 500ppm, the frequency of a circulating pump is set to be 37Hz, the laser power is 340W, the diameter of a light spot is 30 micrometers, the laser scanning speed is 1250mm/s, the scanning interval is 50 micrometers, and the layering thickness is 50 micrometers.

(2) 3D printing: and importing the stl format file into a model layering platform, setting the position, layering the printing model, and transmitting the printing model to a metal 3D printer.

(3) Adjusting the angle of the bracket to enable the a surface to coincide with the substrate, placing the model in the center of the substrate, simulating the molding process of the model by a slicing tool, starting printing after no problem is detected, closely observing in the printing process, and finally obtaining the titanium-based alloy part of the bracket.

A fourth stage: finish machining of 3D printed matter

The 3D printed carrier part is first surface treated with a burnishing tool and then machined. And (3) performing high-precision characteristic finish machining on the printed bracket by adopting a traditional machining technology, machining the part designed in the second stage step 4 at the position, including the characteristics of a machined surface a, a hole, a thread and the like, and finally obtaining the bracket part with the same structure as the original model.

In the processing flow, the metal 3D printing is laser printing, an IPG-YLS-6000 fiber laser is adopted as a heat source, the laser wavelength is 1064nm, a Precitec-YC52 printing head is adopted, an RC-PGF-D-2 type metal powder feeder is adopted, a digital control system adopts four-axis linkage, an inert gas protection glove box, a constant-temperature circulating water-cooled copper substrate, an argon gas carrier flow system and the like are also configured, the equipment has the advantages of large laser transmission power range and high equipment performance, and is suitable for processing of metal materials, part of non-metal materials, laser cladding, laser 3D printing, composite material preparation and the like.

And finishing the integrated molding of the bracket. Generally, in order to reduce the mass of the bracket, the 3D metal printer adopts SLM forming technology and selective laser melting, and the metal powder is a titanium-based alloy material, which has the advantages of high mechanical strength, low elastic modulus, low density, high corrosion resistance, good biocompatibility, and the like.

The method is applied to reverse modeling and rapid molding of the complex structure assembly, and a final three-dimensional model is printed through scanning, CAD model reconstruction and design and rapid molding.

Claims

1. A rocket launch canister carriage, characterized in that: the supporting device comprises a fixed seat (3) and two arc-shaped supporting arms (2), wherein the fixed seat (3) is horizontally arranged, the sections of the supporting arms (2) are groove-shaped plates, one ends of the two supporting arms (2) are connected with two side faces of the left end of the fixed seat (3) to form a semicircular surrounding structure, the other end of each supporting arm (2) is provided with a semi-open connecting end (1), and lightening holes (7) are distributed in the supporting arms (2); a positioning boss (4) is arranged in the middle of the fixing seat (3), a positioning pin hole is formed in the center of the positioning boss (4), a connecting boss (6) integrated with the fixing seat (3) is arranged on one side of the positioning boss (4), and a threaded hole for connection is formed in the center of the connecting boss (6); two parallel thread fixing frames (5) are fixed at the right end of the fixing seat (3), the end parts of the thread fixing frames (5) are round columns, and the centers of the round columns are threaded holes.

2. A rocket launch canister carriage according to claim 1, characterized in that: the middle of the connecting end (1) is provided with a through hole, the upper end face of the connecting end (1) is provided with a sliding groove (12) communicated with the through hole, and the edge of the sliding groove (12) is processed into a 30-degree chamfer.

3. A method of integrally rapid prototyping a bracket as set forth in claim 1, comprising the steps of:

4. The integrated rapid prototyping method of claim 3 wherein: step 2, in the reconstruction process, removing irregular surface patches from the welding part between the fixed seat and the supporting arm of the bracket, and adding the regular characteristic of chamfering; for the surface of the supporting arm of the bracket, a solid model is formed by offsetting based on a large number of sampling points and a component standard curved surface.

5. The integrated rapid prototyping method of claim 3 wherein: in the step 2, the bracket CAD model carries out a high-precision characteristic processing principle: and deleting holes or threaded holes with the diameter less than 8mm on the CAD model of the bracket, reducing the hole diameter of the holes with the diameter more than or equal to 8mm, increasing the hole diameter of the holes with the diameter more than or equal to 1mm along the normal direction for the position of a large machined surface, filling the features of the small machined surface, and removing the features of the position.

6. The integrated rapid prototyping method of claim 3 wherein: the metal 3D printer adopts laser melting printing equipment of SLM forming technology.