阅读说明：本技术 金属零件增材制造控制系统与方法 (Metal part additive manufacturing control system and method ) 是由 周文超 唱丽丽 蒋士春 邢飞 史建军 于 2021-10-29 设计创作，主要内容包括：本发明涉及金属零件增材制造控制系统与方法,包括成型工作台、成型基板、增材制造装置、应力消除装置、换刀装置、控制系统。增材制造装置和应力消除装置固定于换刀装置上,换刀装置可实现两套装置的工作位置的上下调节,通过控制系统实现增材制造和应力消除两种工作模式的切换；应力消除装置通过减震器固定在换刀装置上。系统工作时换刀装置切换增材模式,通过控制系统控制增材制造装置逐层成形零件,换刀装置切换应力消除模式,控制系统控制应力消除装置以一定频率在已成型零件表面接触式运动以消除零件内应力,然后再进行下一次增材制造-应力消除循环,从而在零件逐层堆积的过程中逐层消除零件内应力以控制零件变形。(The invention relates to a metal part additive manufacturing control system and a metal part additive manufacturing control method. The material increase manufacturing device and the stress eliminating device are fixed on the tool changing device, the tool changing device can realize the up-and-down adjustment of the working positions of the two sets of devices, and the switching of two working modes of material increase manufacturing and stress eliminating is realized through the control system; the stress relieving device is fixed on the tool changing device through a shock absorber. When the system works, the tool changing device switches the material adding mode, the control system controls the material adding manufacturing device to form parts layer by layer, the tool changing device switches the stress relieving mode, the control system controls the stress relieving device to move in a contact mode on the surface of the formed part at a certain frequency so as to relieve the internal stress of the part, and then the next material adding manufacturing-stress relieving cycle is carried out, so that the internal stress of the part is relieved layer by layer in the process of stacking the parts layer by layer so as to control the deformation of the part.)

1. A metal part additive manufacturing control system, comprising:

a forming workbench;

a molding base plate fixed on the molding table;

the additive manufacturing device is used for additive manufacturing on the molding substrate in a layer-by-layer accumulation mode;

the stress relieving device is used for relieving the stress of the metal parts printed on the molding substrate;

the tool changing device is used for realizing the up-and-down switching of two working heads of the additive manufacturing device and the stress control device;

the control system is arranged for controlling the switching of two working modes of additive manufacturing and stress relief through the tool changing device;

the tool changing device switches an additive manufacturing mode, and the additive manufacturing device is controlled by the control system to perform layer-by-layer accumulation molding processing of part additive manufacturing on the surface of the molding substrate; the tool changing device switches a stress relieving mode, the control system controls the stress relieving device to perform stress relieving processing on the surface of the formed part layer, and then the next additive manufacturing-stress relieving circulating operation is performed.

2. The metal part additive manufacturing control system of claim 1 wherein the additive manufacturing apparatus comprises a processing head for performing layer-by-layer build-up manufacturing of a metal material additive process, the heat source mode of the processing head being selected from one of laser, arc, electron beam, and forming material being metal powder or metal wire, each layer of which has a thickness in the range of 0.1-2 mm.

3. The metal part additive manufacturing control system of claim 1, wherein the stress relief apparatus is comprised of a milli-energy weld stress relief device and a shock absorber.

4. The metal part additive manufacturing control system of claim 3, wherein the shock absorber is coupled between the milli-energy weld stress relief device and the tool changer, and excess vibrational energy is absorbed by the shock absorber when switching to the stress relief mode for stress relief work.

5. The metal part additive manufacturing control system of claim 3, wherein in the stress relief mode, the working contact of the milli-energy welding stress relief device is in contact with a surface of the formed part layer and is configured to dither at a set frequency range normal to the formed surface.

6. The metal part additive manufacturing control system of claim 5, wherein the working contact of the milliwatt energy welding stress relief device is vibrated at a frequency in the range of 20-40KHz at an output amplitude in the range of 30-50 μm at a travel speed of 20-40 m/h.

7. The metal part additive manufacturing control system of claim 5, wherein the tool changer controls switching between the two process modes by changing relative positions of the additive manufacturing device and the stress relief device in a machining height direction.

8. The metal part additive manufacturing control method implemented by the metal part additive manufacturing control system according to any one of claims 1 to 7, wherein in the process of additive manufacturing the metal part, a printing and stress relief composite process is performed as follows:

(1) the control system controls the additive manufacturing device to stack a predetermined number of stacked layers of parts to be molded on the molding substrate according to a preset processing track;

(2) the control system controls the tool changing device to switch the processing mode, namely, the processing head of the additive manufacturing device is retracted and switched to a stress relief working mode;

(3) the control system controls the stress relieving device to perform high-frequency vibration in the height direction and displacement motion in the horizontal direction on the surface of the formed accumulation layer at a certain frequency according to a preset processing track to finish stress removing processing;

(4) the control system controls the tool changing device to switch the machining mode, the working contact of the stress relieving device is retracted, and the system is switched to the additive machining working mode;

(5) and (4) repeating the processes from (1) to (4) until the additive manufacturing of the part is completed.

9. The method according to claim 8, wherein the stress relief device is a milliwatt welding stress relief apparatus, and in the stress relief mode, the working contact is in contact with the surface of the formed stack layer to vibrate at high frequency, the vibration frequency is 20-40KHz, the output amplitude is 30-50 μm, and the moving speed is 20-40 m/h.

10. The metal part additive manufacturing control method according to claim 8, wherein the predetermined number of layers is 1 to 3 layers, and a layer thickness of each layer is in a range of 0.1 to 2 mm.

Technical Field

The invention relates to the technical field of metal additive manufacturing, in particular to a metal part additive manufacturing control system and a metal part additive manufacturing control method.

Background

The metal additive manufacturing technology is mainly characterized in that a prototype manufacturing process of a metal product is realized by depositing and stacking metal materials layer by layer through a local heat source, and is different from the traditional subtractive manufacturing-metal turning and equivalent manufacturing-casting technology.

As the additive manufacturing is a multi-physical-field composite process, which relates to the form selection of a heat source, the thermal shrinkage of a molten drop forming process, the thermal temperature difference between layers, a post-processing process after forming and the like, the additive manufacturing is a process in which a temperature field, a force field and a stress field influence and interact. The interaction of heat and force in the layer-by-layer accumulation process of molten drops in the additive manufacturing process also causes the layer-by-layer formation and accumulation of the stress of a forming structure, and the stress can cause risks such as warping deformation, even component cracking and the like in the manufacturing process, thereby causing interference to the dimensional precision guarantee of the part manufacturing process; if the residual stress is not removed in time after the manufacture, some stress will be released naturally with time, and the accumulated deformation of the part will cause the deformation to exceed the design tolerance.

In order to solve the problems, the existing researchers combine a metal additive manufacturing technology with parallel control, stress detection and an ultrasonic strengthening process, so that the stress deformation problem in the additive manufacturing process is solved. For example, patent CN106735967B discloses a method for shape control and controllability of ultrasonic vibration assisted arc additive manufacturing, which improves nucleation rate by applying non-contact ultrasonic vibration during additive manufacturing process, thereby performing the function of refining molten pool crystal grains, and simultaneously reducing the generation of internal defects of the formed part, thereby improving the mechanical properties of the part, but this method cannot fundamentally eliminate the internal stress generated during the production process of the formed part. Patent CN110586941A discloses a deformation control system and method in the metal part additive manufacturing process, which applies a stress detection and stress relief device on the bottom of a forming workpiece, thereby relieving stress in the process of stacking parts layer by layer, controlling part deformation, and improving the shape and size precision of the part.

Currently, there is still a lack of effective means and methods for stress relief and deformation control in additive manufacturing processes. The quality of the metal part, particularly the bearing part, not only requires that the mechanical property reaches the standard, but also requires that the shape, the size and even the precision of the manufactured metal part reach the design requirements, and the stress deformation is a pain point problem to be solved urgently for the metal part additive manufacturing industry.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a metal part additive manufacturing control system, which is used for improving the stress in the metal part additive manufacturing process, effectively relieving the stress accumulation problem in the additive manufacturing process by adding a stress relief process in the additive manufacturing process, solving the additive defects of deformation, cracking and the like of a workpiece caused by the stress and improving the shape and size precision of the part.

To achieve the above object, a first aspect of the present invention provides a metal part additive manufacturing control system, including:

a forming workbench;

a molding base plate fixed on the molding table;

the additive manufacturing device is used for additive manufacturing on the molding substrate in a layer-by-layer accumulation mode;

the stress relieving device is used for relieving the stress of the metal parts printed on the molding substrate;

the tool changing device is used for realizing the up-and-down switching of two working heads of the additive manufacturing device and the stress control device;

the control system is arranged for controlling the switching of two working modes of additive manufacturing and stress relief through the tool changing device;

the tool changing device switches an additive manufacturing mode, and the additive manufacturing device is controlled by the control system to perform layer-by-layer accumulation molding processing of part additive manufacturing on the surface of the molding substrate; the tool changing device switches a stress relieving mode, the control system controls the stress relieving device to perform stress relieving processing on the surface of the formed part layer, and then the next additive manufacturing-stress relieving circulating operation is performed.

Preferably, the additive manufacturing device comprises a processing head for completing the layer-by-layer build-up manufacturing of the metal material additive process, the heat source mode of the processing head is selected from one of laser, electric arc and electron beam, the forming material is metal powder or metal wire, and the layer thickness of each layer is 0.1-2 mm.

Preferably, the stress relief means consists of a milligram energy welding stress relief device and a shock absorber.

Preferably, the shock absorber is connected between the milligram energy welding stress relief device and the tool changer, and when the stress relief mode is switched to the stress relief mode for stress relief work, redundant vibration energy is absorbed through the shock absorber.

Preferably, in the stress relief mode, the working contact of the milliwatt welding stress relief device is in contact with the surface of the molded part layer and is configured to vibrate at a high frequency perpendicular to the molding surface in a set frequency range.

Preferably, the working contact of the milligram energy welding stress relief device is vibrated at high frequency within the frequency range of 20-40KHz, the output amplitude range is 30-50 μm, and the moving speed is 20-40 m/h.

Preferably, the tool changing device controls and realizes the switching of the two process modes by changing the relative positions of the additive manufacturing device and the stress relief device in the machining height direction.

The second aspect of the invention provides a metal part additive manufacturing control method, in the process of additive manufacturing of a metal part, a printing and stress relief composite process is performed according to the following modes:

(1) the control system controls the additive manufacturing device to stack a predetermined number of stacked layers of parts to be molded on the molding substrate according to a preset processing track;

(2) the control system controls the tool changing device to switch the processing mode, namely, the processing head of the additive manufacturing device is retracted and switched to a stress relief working mode;

(3) the control system controls the stress relieving device to perform high-frequency vibration in the height direction and displacement motion in the horizontal direction on the surface of the formed accumulation layer at a certain frequency according to a preset processing track to finish stress removing processing;

(4) the control system controls the tool changing device to switch the machining mode, the working contact of the stress relieving device is retracted, and the system is switched to the additive machining working mode;

(5) and (4) repeating the processes from (1) to (4) until the additive manufacturing of the part is completed.

Preferably, the stress relieving device is milligram energy welding stress relieving equipment, and in a stress relieving mode, the working contact of the stress relieving device is in contact with the surface of the formed accumulation layer to vibrate at high frequency, the vibration frequency range is 20-40KHz, the output amplitude range is 30-50 mu m, and the moving speed is 20-40 m/h.

Preferably, the predetermined number of layers is 1 to 3 layers, each layer having a layer thickness in the range of 0.1 to 2 mm.

By combining the technical scheme, the invention has the remarkable beneficial effects that:

according to the invention, the additive manufacturing process and the stress relieving process are combined, so that the stress deformation in the additive manufacturing process is effectively controlled, the problem that the existing additive manufacturing depends on the increase of the machining allowance to compensate the stress deformation is solved, the manufacturing and machining cost is saved, and the dimensional accuracy of the additive manufacturing part is ensured;

according to the invention, a composite process flow of layer-by-layer material increase-stress relief is adopted, and the stress is relieved layer by using the material increase idea in the processing process aiming at the problem of large stress in the material increase part processing process, so that the original process effect of relieving stress and annealing after the material increase of the part is finished is achieved.

It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent. In addition, all combinations of claimed subject matter are considered a part of the presently disclosed subject matter.

The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.

Drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic structural diagram of a metal part additive manufacturing control system according to an embodiment of the present invention;

FIG. 2 is a schematic view of an additive manufacturing model according to an embodiment of the invention;

FIG. 3 is a schematic view of a stress relief mode of an embodiment of the present invention;

fig. 4 is a flowchart of a metal part additive manufacturing control method according to an embodiment of the present invention.

In the drawings, wherein like reference numerals are used to refer to like elements or functional structures, the reference numerals have the following meanings:

1 forming workbench, 2 forming substrate, 3 shock absorbers, 4 tool changing devices, 5 stress relieving devices, 6 control systems and 7 additive manufacturing devices.

Detailed Description

In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.

In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily intended to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.

Referring to fig. 1 to 3, a metal part additive manufacturing control system according to an exemplary embodiment of the present invention includes a forming table 1, a forming substrate 2, a damper 3, a tool changer 4, a stress relief device 5, a control system 6, and an additive manufacturing device 7.

A molding base plate 2 fixed to the molding table 1; the forming substrate 2 and the forming workbench 1 can be fixed through bolts, and metal parts grow upwards from the surface of the forming substrate 1 through an additive manufacturing process.

And an additive manufacturing device 7 for performing additive manufacturing on the molding substrate by layer-by-layer deposition.

And the stress relieving device 5 is used for relieving the stress of the metal parts printed on the molding substrate.

The tool changing device 4 is used for realizing the up-and-down switching of two working heads of the additive manufacturing device and the stress control device;

and the control system is arranged to control the material increase manufacturing and stress relief working mode switching through the tool changing device, namely, the tool changing device is controlled to switch 2 working heads of the material increase manufacturing device and the stress relief device up and down to realize the working mode switching, and the tool changing device is used for controlling the material increase manufacturing device and the stress relief device to realize the switching of two process modes by changing the relative positions in the machining height direction, so that mutual influence and interference are avoided.

The tool changing device switches an additive manufacturing mode, and the additive manufacturing device is controlled by the control system to perform layer-by-layer accumulation molding processing of part additive manufacturing on the surface of the molding substrate; the tool changing device switches a stress relieving mode, the control system controls the stress relieving device to perform stress relieving processing on the surface of the formed part layer, and then the next additive manufacturing-stress relieving circulating operation is performed.

Preferably, the additive manufacturing apparatus 7 comprises a processing head and an additive manufacturing component to which it is attached, and the printing of the metal part is done in an additive manufacturing process build up layer by layer in an additive manufacturing mode. In alternative embodiments, the heat source mode of the process head may be selected from laser, arc, electron beam, etc., and the forming material may be a metal powder or a metal wire having a layer thickness in the range of 0.1-2 mm.

In connection with the illustration, the stress relief means 5 consists of a milliwatt welding stress relief device and a shock absorber. The shock absorber is connected between the milligram energy welding stress relief device and the tool changing device, and when the stress relief mode is switched to a stress relief mode for stress relief operation, redundant vibration energy is absorbed through the shock absorber.

The stress relieving device 5 is milligram energy welding stress relieving equipment, when the stress relieving process operation is carried out, a working contact of the milligram energy welding stress relieving equipment is in contact with the surface of the formed part layer and is arranged to carry out high-frequency vibration in a set frequency range vertical to the forming surface, the frequency range is 20-40KHz, the output amplitude range is 30-50 mu m, and the moving speed is 20-40 m/h.

It should be understood that in embodiments of the present invention, the control system 6 may employ an industrial computer system as the control system, which is connected to the additive manufacturing apparatus, the stress relief apparatus, and the tool changer to provide motion control of the entire system.

In connection with the design of the metal part additive manufacturing control system shown in fig. 1-3, in the process of additive manufacturing a metal part, the additive manufacturing and stress relief composite process is performed in the following manner:

(1) the control system controls the additive manufacturing device to stack a predetermined number of stacked layers of parts to be molded on the molding substrate according to a preset processing track;

(2) the control system controls the tool changing device to switch the processing mode, namely, the processing head of the additive manufacturing device is retracted and switched to a stress relief working mode;

(3) the control system controls the stress relieving device to perform high-frequency vibration in the height direction and displacement motion in the horizontal direction on the surface of the formed accumulation layer at a certain frequency according to a preset processing track to finish stress removing processing;

(4) the control system controls the tool changing device to switch the machining mode, the working contact of the stress relieving device is retracted, and the system is switched to the additive machining working mode;

(5) and (4) repeating the processes from (1) to (4) until the additive manufacturing of the part is completed.

Therefore, by combining the additive manufacturing process with the stress relief process, the stress deformation in the additive manufacturing process is effectively controlled, the problem that the existing additive manufacturing depends on increasing the machining allowance to compensate the stress deformation is solved, the manufacturing and machining cost is saved, and the dimensional accuracy of the additive manufactured part is ensured; meanwhile, the invention adopts a composite process flow of layer-by-layer material increase and stress relief, and aims at the problem of large stress in the material increase part processing process, the stress is relieved layer by using the material increase idea in the processing process, and the original process effect of relieving stress and annealing after the material increase of the part is finished is achieved.

Preferably, in the additive manufacturing composite process, the predetermined number of layers is 1 to 3, and the layer thickness of each layer is 0.1 to 2 mm.

With reference to fig. 4, to implement an exemplary process of the additive manufacturing and stress relief composite process, the following is specifically performed:

(1) dividing the three-dimensional model of the part to be molded into slices, and filling paths and setting parameters for each layer to generate m layers of part processing programs; the method can be realized by RC-CAM additive manufacturing process planning software of Nanjing Koyu light control laser technology company, and can realize the planning of wire feeding or powder feeding additive manufacturing process;

(2) when n is equal to 1, introducing a machining program of the nth layer of part, and controlling the additive manufacturing device to stack one layer of parts to be formed on the substrate by the control system according to a preset machining track to finish additive manufacturing of the nth layer of part;

(3) the control system controls the tool changing device to switch the machining mode, the machining head of the material adding device is retracted, and the system is switched to a stress relief working mode;

(4) the control system controls the stress relief device to perform high-frequency vibration in the height direction and displacement motion in the horizontal direction on the surface of the formed part layer at a certain frequency according to a preset processing track to finish the stress relief processing of the part on the nth layer;

(5) if n is smaller than m, the control system controls the tool changing device to switch the machining mode, the machining head of the stress relieving device is retracted, the system is switched to the additive machining working mode, and the processes from (1) to (5) are repeated;

(6) and finishing the additive manufacturing of the part until n is m.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.