CN108958341B - Atmosphere control system and method for additive manufacturing laser forming equipment - Google Patents
Atmosphere control system and method for additive manufacturing laser forming equipment Download PDFInfo
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- CN108958341B CN108958341B CN201811105995.2A CN201811105995A CN108958341B CN 108958341 B CN108958341 B CN 108958341B CN 201811105995 A CN201811105995 A CN 201811105995A CN 108958341 B CN108958341 B CN 108958341B
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- 238000000034 method Methods 0.000 title claims abstract description 79
- 239000000654 additive Substances 0.000 title claims abstract description 27
- 230000000996 additive effect Effects 0.000 title claims abstract description 27
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 239000007789 gas Substances 0.000 claims abstract description 101
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 50
- 239000001301 oxygen Substances 0.000 claims abstract description 44
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 44
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 43
- 239000011261 inert gas Substances 0.000 claims abstract description 30
- 238000004891 communication Methods 0.000 claims abstract description 11
- 238000007664 blowing Methods 0.000 claims abstract description 4
- 230000001105 regulatory effect Effects 0.000 claims description 52
- 239000000428 dust Substances 0.000 claims description 50
- 238000000465 moulding Methods 0.000 claims description 22
- 239000000843 powder Substances 0.000 claims description 15
- 230000001276 controlling effect Effects 0.000 claims description 13
- 238000006073 displacement reaction Methods 0.000 claims description 11
- 238000001514 detection method Methods 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 3
- 238000007790 scraping Methods 0.000 claims description 3
- 230000007423 decrease Effects 0.000 claims description 2
- 239000002699 waste material Substances 0.000 abstract description 5
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000000844 transformation Methods 0.000 description 1
Classifications
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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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/30—Process control
- B22F10/32—Process control of the atmosphere, e.g. composition or pressure in a building chamber
-
- 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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/30—Process control
- B22F10/32—Process control of the atmosphere, e.g. composition or pressure in a building chamber
- B22F10/322—Process control of the atmosphere, e.g. composition or pressure in a building chamber of the gas flow, e.g. rate or direction
-
- 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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/80—Data acquisition or data processing
- B22F10/85—Data acquisition or data processing for controlling or regulating additive manufacturing processes
-
- 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
- B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
- B22F12/70—Gas flow means
-
- 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
- B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
- B22F12/90—Means for process control, e.g. cameras or sensors
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y10/00—Processes of additive manufacturing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Automation & Control Theory (AREA)
- Analytical Chemistry (AREA)
- Flow Control (AREA)
- Lasers (AREA)
Abstract
The invention relates to an atmosphere control system and method of additive manufacturing laser forming equipment, belonging to the technical field of additive manufacturing, wherein the system comprises: the inert gas replacement unit is used for calculating the required replacement gas amount according to the volume of the communication space of the forming area and the set oxygen content and controlling gas replacement in the forming cavity; the pressure stabilizing unit is used for adjusting the pressure in the forming cavity in the forming process; and the differential pressure adjusting unit is used for adjusting the blowing air quantity in the forming process. The system is used for atmosphere control and is divided into an early system debugging process and a later automatic control process, so that the technical problems of inert gas waste, complex control program, inconsistent gas parameters and poor interchangeability in the atmosphere control of the additive manufacturing laser forming equipment in the prior art are solved, the gas waste is reduced, the stability is improved, the debugging parameters such as pressure, flow and differential pressure are unified, and the interchangeability of batch equipment is improved.
Description
Technical Field
The invention belongs to the technical field of additive manufacturing, and particularly relates to an atmosphere control system and method for laser forming equipment in additive manufacturing.
Background
Currently, the mainstream technology of additive manufacturing in industrial application is a technology of melting or bonding and forming powder by using laser as an energy source, for example SLM, SLS, LSF. During the process of melting the powder, the laser can react with gases such as oxygen, nitrogen and the like, so that the quality of the formed part is unqualified. To prevent oxidation during powder melting, the processing area of typical additive manufacturing laser forming equipment is under inert gas protection or in a vacuum environment.
The following methods are generally used in the prior art for atmosphere control: firstly, the inlet amount of inert gas in each part of equipment is regulated through an inlet valve, an exhaust valve and a manual flow meter, the oxygen content of a forming area is detected through an oxygen sensor, when the oxygen content is low, a large-flow inert gas inlet valve is closed, and a small-flow inert gas inlet valve is opened, so that the required atmosphere environment in the whole forming process is maintained.
However, the above technique has the following disadvantages: (1) The small flow rate gas is always introduced in the whole forming process, so that the oxygen content is continuously reduced after meeting the requirement, thereby causing unnecessary waste; (2) In the forming process, the oxygen content is increased accidentally, so that the high-flow gas and the low-flow gas are switched back and forth, the control procedure is troublesome, and the equipment stability is poor; (3) According to the installation difference, sealing difference and the like of different equipment of the same model, the required small flow gas values are different, so that the gas circuit debugging parameters of the batch equipment are inconsistent; (4) In the forming process, the internal pressure of the cavities of different equipment of the same type is inconsistent according to the conditions of installation difference, sealing difference, gas circuit control and the like, so that the detected pressure value is inconsistent, flow parameters, differential pressure parameters and the like in the system are affected, and finally, the parameter values of a fan and a filtering system are affected, so that equipment debugging is difficult and interchangeability is poor. Therefore, how to make the molding area possess a better pneumatic control environment is a problem to be solved.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides an atmosphere control system and an atmosphere control method for additive manufacturing laser forming equipment, which are used for controlling the atmosphere and solve the technical problems of inert gas waste, complex control program, inconsistent gas parameters and poor interchangeability existing in the atmosphere control of the additive manufacturing laser forming equipment in the prior art.
One of the objects of the present invention is to provide an atmosphere control system of an additive manufacturing laser forming apparatus, comprising:
the inert gas replacement unit is used for calculating the required replacement gas amount according to the volume of the communication space of the forming area and the set oxygen content and controlling gas replacement in the forming cavity;
the pressure stabilizing unit is used for adjusting the pressure in the forming cavity in the forming process;
and the differential pressure adjusting unit is used for adjusting the blowing air quantity in the forming process.
In the above technical solution, preferably, the inert gas substitution unit includes a gas substitution controller;
and connected to the gas displacement controller: the device comprises a dust removal cabinet air inlet valve, a dust removal cabinet air outlet valve, a gas replacement air inlet valve and a gas replacement air outlet valve, which are respectively controlled into a first flow control valve, a second flow control valve, a third flow control valve and a fourth flow control valve of the air inlet flow of a cavity, a powder collection groove, a forming shaft and the dust removal cabinet, an electronic flowmeter for measuring the total air inlet amount in the whole gas replacement process, and an oxygen sensor for detecting the oxygen content of the gas in the forming cavity; the air inlet valve, the flow control valve IV, the dust removing cabinet and the air outlet valve of the dust removing cabinet are sequentially connected, the air replacement air inlet valve, the flow control valve I, the forming cavity body and the air replacement air outlet valve are sequentially connected, the air replacement air inlet valve, the flow control valve II and the powder collecting groove are sequentially connected, the air replacement air inlet valve, the flow control valve III and the forming shaft are sequentially connected, and the electronic flowmeter is respectively connected with the air replacement air inlet valve and the air inlet valve of the dust removing cabinet.
When the gas is replaced in the early stage of the forming process, the gas inlet and outlet valves and the gas replacement inlet and outlet valves of the dust removing cabinet are opened, and the gas inlet and outlet valves and the gas replacement inlet and outlet valves of the dust removing cabinet are closed when the oxygen content is reduced below a set value through feedback signals of the electronic flowmeter and the oxygen sensor.
In the above technical solution, preferably, the voltage stabilizing unit includes a voltage stabilizing controller;
and the voltage stabilizing controller is connected with: the pressure stabilizing air inlet valve, the pressure stabilizing air outlet valve, an electronic pressure regulating valve for controlling the pressure in the forming cavity and a pressure sensor for detecting the pressure in the forming cavity; the pressure stabilizing air inlet valve, the electronic pressure regulating valve, the optical system lens group, the forming cavity and the pressure stabilizing air outlet valve are sequentially connected.
In the equipment preparation process and the forming process, the pressure stabilizing controller controls the electronic pressure regulating valve and the pressure stabilizing air inlet valve to be opened and closed according to the pressure value fed back by the pressure sensor of the forming cavity.
In the above technical solution, preferably, the differential pressure adjusting unit includes a differential pressure adjusting controller;
and connected to the differential pressure regulator controller: a differential pressure sensor for detecting differential pressure between the filter element and the air inlet pipe, and a frequency converter of the fan.
In the equipment molding process, the differential pressure regulating controller regulates the air quantity of the fan according to the feedback value of the differential pressure sensor to ensure that the molding surface is uniformly blown.
In the above technical scheme, it is further preferable that the dust removing device further comprises an exhaust filter, wherein the exhaust filter is respectively connected with the exhaust valve of the dust removing cabinet, the gas replacement exhaust valve and the pressure stabilizing exhaust valve.
The exhaust filter filters and discharges the gas discharged from the dust removing cabinet and the forming cavity.
In the above technical solution, it is further preferable that the electronic flowmeter is disposed on an inert gas inlet main pipe of the entire control system, and a manual control main valve and a pressure regulating valve are further disposed on the main pipe at the inert gas inlet. To control the opening and closing of the main pipe and the intake pressure of the whole system.
Another object of the present invention is to provide an atmosphere control method of an additive manufacturing laser forming apparatus, comprising the steps of:
1) And (3) controlling a voltage stabilizing unit: maintaining the system pressure at a set point;
2) And controlling an inert gas replacement unit: filling inert gas into the communication space needing gas replacement for gas replacement by opening the gas inlet and outlet control valve, detecting the gas oxygen content in the molding cavity by using an oxygen sensor, and closing the gas inlet and outlet control valve when the gas oxygen content reaches a threshold value;
3) Control differential pressure regulating unit: and detecting the air quantity in the forming cavity in the forming process, and adjusting a frequency converter of the fan to control the fan when the air quantity changes, so as to ensure that the air quantity is unchanged.
The specific process of the step 1) is as follows: sealing the molding cavity, inputting a required pressure value, opening a pressure stabilizing controller button, opening a pressure stabilizing air inlet valve and an electronic pressure regulating valve, enabling the system to reach the required pressure, and closing the pressure stabilizing air inlet valve and the electronic pressure regulating valve; debugging the forming shaft and the powder scraping device, when the forming shaft platform descends, the forming cavity volume increases, the pressure decreases, the pressure stabilizing air inlet valve is opened, the electronic pressure regulating valve is opened, and the regulating system pressure reaches a set value; when the forming shaft platform rises, the volume of the forming cavity is reduced, the pressure rises, the pressure-stabilizing exhaust valve is frequently opened and closed, and the pressure of the regulating system reaches a set value and is accompanied with the generation of exhaust.
The specific process of the step 2) is as follows: opening a button of a gas replacement controller, opening an air inlet valve of the dust removal cabinet, opening an air outlet valve of the dust removal cabinet, opening the air inlet valve of the gas replacement, opening the air outlet valve of the gas replacement, gradually reducing the detection value of an oxygen sensor of a molding cavity, opening a fan, and closing the air inlet valve of the dust removal cabinet, the air outlet valve of the dust removal cabinet, the air inlet valve of the gas replacement and the air outlet valve of the gas replacement when the detection value of the oxygen sensor is lower than a required value; when the oxygen content increases and exceeds the required value due to any reason, the valve is restarted to perform gas replacement.
The specific process of the step 3) is as follows: when the filter element is used for a long time, the feedback value of the differential pressure sensor of the filter element is increased, a button of the differential pressure adjusting controller is started, the variable frequency value of the fan is automatically adjusted by the differential pressure adjusting controller to be increased, the air quantity is ensured to be unchanged, and the forming process is finished. If the differential pressure of the filter element reaches the alarm value during the forming process, the forming process is stopped, and the filter element is replaced and the forming process is newly equipped.
The invention has the advantages and positive effects that:
according to the invention, through the automatically controlled inert gas replacement unit, the pressure stabilizing unit and the differential pressure regulating unit, the gas waste is reduced, the stability is improved, the debugging parameters such as pressure, flow, differential pressure and the like are unified, and the interchangeability of batch equipment is improved.
Drawings
FIG. 1 is a schematic diagram of an atmosphere control system of an additive manufacturing laser forming apparatus according to an embodiment of the present invention;
FIG. 2 is a flow chart of atmosphere control of a pressure stabilizing unit and an inert gas replacement unit of an atmosphere control system of an additive manufacturing laser forming device according to an embodiment of the present invention;
fig. 3 is an atmosphere control flow chart of a differential pressure adjusting unit of a forming process of an atmosphere control system of an additive manufacturing laser forming device according to an embodiment of the present invention.
In the figure: 1-molding cavity, 2-molding shaft, 3-powder collecting groove, 4-optical system lens group, 5-filter element, 6-fan, 7-dust removing cabinet, 8-exhaust filter, 9-air inlet pipe, 10-air outlet pipe, V1-manual control main valve, V2-dust removing cabinet air inlet valve, V3-gas replacement air inlet valve, V4-pressure stabilizing air inlet valve, V5-dust removing cabinet air outlet valve, V6-pressure stabilizing air outlet valve, V7-gas replacement air outlet valve, V8-flow regulating valve, R1-pressure regulating valve, R2-electronic pressure regulating valve, R3-flow regulating valve I, R4-flow regulating valve II, R5-flow regulating valve III, R6-flow regulating valve IV, SQ-electronic flowmeter, SP-pressure sensor, SO 2- Oxygen sensor, sΔp-differential pressure sensor, SV-wind meter.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the examples and the accompanying drawings. It will be appreciated by those of skill in the art that the following specific examples or embodiments are provided as a series of preferred embodiments of the invention, and that the embodiments may be combined or otherwise interrelated, unless one or more specific examples or embodiments are specifically set forth herein as being not intended to be interrelated or co-usable with other examples or embodiments. Meanwhile, the following specific examples or embodiments are merely provided as an optimized arrangement, and are not to be construed as limiting the scope of the present invention.
Furthermore, those skilled in the art should appreciate that the specific values for parameter settings set forth in the following detailed description and examples are for illustrative purposes and are not to be construed as limiting the scope of the invention; the algorithms and their parameter settings referred to herein are also for illustrative purposes only and form transformations of the parameters described below, as well as conventional mathematical derivations of the algorithms described below, are considered to fall within the scope of the present invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1
Referring to fig. 1, the present embodiment provides an atmosphere control system of an additive manufacturing laser forming apparatus, including:
the inert gas replacement unit is used for calculating the required replacement gas amount according to the volume of the communication space of the forming area and the set oxygen content and controlling gas replacement in the forming cavity;
the pressure stabilizing unit is used for adjusting the pressure in the forming cavity in the forming process;
and the differential pressure adjusting unit is used for adjusting the blowing air quantity in the forming process.
As a preferred embodiment, the inert gas displacement unit comprises a gas displacement controller;
and connected to the gas displacement controller: the dust removing cabinet air inlet valve V2, the dust removing cabinet air outlet valve V5, the air replacing air inlet valve V3 and the air replacing air outlet valve V7 are respectively controlled to be a first flow control valve R3, a second flow control valve R4, a third flow control valve R5 and a fourth flow control valve R6 of air inlet flow of the cavity body 1, the powder collecting groove 3, the forming shaft 2 and the dust removing cabinet 7, an electronic flowmeter SQ for measuring the total air inlet amount in the whole air replacing process, and an oxygen sensor SO for detecting the oxygen content of air in the forming cavity body 2 The method comprises the steps of carrying out a first treatment on the surface of the The dust removing cabinet air inlet valve V2, the flow control valve four R6, the dust removing cabinet 7 and the dust removing cabinet exhaust valve V5 are sequentially connected, the gas replacement air inlet valve V3, the flow control valve one R3, the molding cavity 1 and the gas replacement exhaust valve V7 are sequentially connected, the gas replacement air inlet valve V3, the flow control valve two R4 and the dust collecting groove 3 are sequentially connected, and the gas replacement air inlet valve V3 and the flow control valveThe valve making valve III R5 is sequentially connected with the forming shaft 2, and the electronic flowmeter SQ is respectively connected with the gas replacement gas inlet valve V3 and the dust removal cabinet gas inlet valve V2.
When the gas is replaced in the early stage of the forming process, the gas inlet and outlet valves and the gas replacement inlet and outlet valves of the dust removing cabinet are opened, and the gas inlet and outlet valves and the gas replacement inlet and outlet valves of the dust removing cabinet are closed when the oxygen content is reduced below a set value through feedback signals of the electronic flowmeter and the oxygen sensor.
As a preferred embodiment, the voltage stabilizing unit includes a voltage stabilizing controller;
and connected with the voltage stabilizing controller: a pressure-stabilizing air inlet valve V4, a pressure-stabilizing air outlet valve V6, an electronic pressure regulating valve R2 for controlling the pressure in the molding cavity, and a pressure sensor SP for detecting the pressure in the molding cavity; the pressure-stabilizing air inlet valve V4, the electronic pressure regulating valve R2, the optical system lens group 4, the forming cavity 1 and the pressure-stabilizing air outlet valve V6 are sequentially connected.
In the equipment preparation process and the forming process, the pressure stabilizing controller controls the electronic pressure regulating valve and the pressure stabilizing air inlet valve to be opened and closed according to the pressure value fed back by the pressure sensor of the forming cavity.
As a preferred embodiment, the differential pressure regulating unit comprises a differential pressure regulating controller;
and connected to the differential pressure regulator controller: a differential pressure sensor sΔp for detecting a differential pressure between the filter element 5 and the air inlet pipe 9, and a frequency converter of the fan 6.
In the equipment molding process, the differential pressure regulating controller regulates the air quantity of the fan according to the feedback value of the differential pressure sensor to ensure that the molding surface is uniformly blown.
As a further preferred embodiment, the dust collector further comprises an exhaust filter 8, wherein the exhaust filter 8 is respectively connected with the exhaust valve V5, the gas replacement exhaust valve V7 and the pressure stabilizing exhaust valve V6 of the dust collector.
The exhaust filter filters and discharges the gas discharged from the dust removing cabinet and the forming cavity.
As a further preferred embodiment, the electronic flowmeter SQ is provided on the inert gas inlet main pipe of the entire control system, and a manual main valve V1 and a pressure regulating valve R1 are also provided on the main pipe at the inert gas inlet. To control the opening and closing of the main pipe and the intake pressure of the whole system.
Example 2
The embodiment provides an atmosphere control method of additive manufacturing laser forming equipment, which is mainly used for a later automatic control process and comprises the following steps:
1) And (3) controlling a voltage stabilizing unit: maintaining the system pressure at a set point;
2) And controlling an inert gas replacement unit: filling inert gas into the communication space needing gas replacement for gas replacement by opening the gas inlet and outlet control valve, detecting the gas oxygen content in the molding cavity by using an oxygen sensor, and closing the gas inlet and outlet control valve when the gas oxygen content reaches a threshold value;
3) Control differential pressure regulating unit: and detecting the air quantity in the forming cavity in the forming process, and adjusting a frequency converter of the fan to control the fan when the air quantity changes, so as to ensure that the air quantity is unchanged.
Before the later automatic control process, a pre-system debugging process is needed, wherein the pre-system debugging comprises inert gas replacement unit debugging, voltage stabilizing unit debugging and differential pressure adjusting unit debugging.
Referring to fig. 1, in the early system debugging process, the inert gas replacement unit debugging specific process is as follows: firstly, calculating the volume of all the communication spaces needing gas replacement of the molding cavity 1, the molding shaft 2, the powder collecting tank 3 and the dust removing cabinet 7, and then calculating the air inlet flow required by each volume when the oxygen content is reduced to a required value according to the volume of the communication spaces needing gas replacement.
More specifically, the volume V of all the communication spaces needing gas replacement, such as the molding cavity 1, the molding shaft 2, the powder collecting groove 3, the dust removing cabinet 7 and the like, is calculated 1 、V 2 、V 3 、V 7 Etc. and using a complete mix permutation formula(wherein V t To the required air volume, V R To displace volume C 1 For the initial oxygen content of the vessel, C 2 For the final oxygen content of the vessel), the calculation is to be performedOxygen content from C 1 (21% in atmosphere) down to C 2 Displacement volume V at (demand value) R (V R ＝V 1 +V 2 +V 3 +V 7 ) The total gas volume V required t Re-use formula->(wherein Q is a gas displacement flow value, t is the time required by the gas displacement process), and finally the required air inlet flow Q in the whole gas displacement process is obtained, and then the air inlet flow Q passes through +.>Respectively calculating the required intake air flow Q of each volume 1 、Q 2 、Q 3 、Q 7 A value; then the first flow control valve R3, the second flow control valve R4, the third flow control valve R5 and the fourth flow control valve R6 are closed, and the dust removing cabinet air inlet valve V2, the gas replacing air inlet valve V3, the dust removing cabinet air outlet valve V5 and the gas replacing air outlet valve V7 are opened; the first flow control valve R3, the second flow control valve R4, the third flow control valve R5 and the fourth flow control valve R6 are adjusted one by one, and the output flow of the first flow control valve R3, the second flow control valve R4, the third flow control valve R5 and the fourth flow control valve R6 is ensured to be calculated Q by referring to the display value in the electronic flowmeter SQ 1 、Q 3 、Q 2 、Q 7 Values.
In the early system debugging process, the specific debugging process of the voltage stabilizing unit is as follows: opening the pressure-stabilizing air inlet valve V4 and the electronic pressure regulating valve R2, gradually regulating the electronic pressure regulating valve R2 by an input value W from a lower limit value, and reading a pressure value P corresponding to the pressure sensor SP to obtain the relation between W and P; and converting the input value W into an input pressure related value P0 to obtain the corresponding relation between P0 and P.
In the early system debugging process, the differential pressure adjusting unit debugging specific process is as follows: firstly, an air gauge SV is arranged on an air outlet pipe 10, a flow regulating valve V8 is arranged on an air inlet pipe 9, a pressure stabilizing unit is started and a fan 6 is started according to pressure values required in the forming process of different materials, the air quantity of the fan is regulated to enable the air gauge SV to reach a set value, and the value of a differential pressure sensor Sdelta P is recorded; gradually closing the flow regulating valve V8, increasing the variable frequency value of the fan 6, keeping the air volume instrument SV at a required value, and recording the corresponding relation between the value of the differential pressure sensor (the alarm value not exceeding the requirement of replacing the filter element) and the variable frequency value of the fan.
After the debugging is completed, the air gauge SV and the flow regulating valve V8 are removed when the equipment works normally. An automatic control process is adopted.
Referring to fig. 2, the apparatus is in a ready state before operation, the molding cavity 1 is sealed, the system pressure is 0, a required pressure value P0 is input, a pressure stabilizing controller button is opened, a pressure stabilizing air inlet valve V4 is opened, an electronic pressure regulating valve R2 is opened, the system reaches the required pressure, and the pressure stabilizing air inlet valve and the electronic pressure regulating valve are closed; debugging the forming shaft 2 and the powder scraping device, when the forming shaft 2 descends, the volume of the forming cavity 1 increases, the pressure is reduced, the pressure stabilizing air inlet valve V4 is opened, the electronic pressure regulating valve R2 is opened, the pressure of the regulating system reaches a set value, air inlet is generated around the mirror surface, and powder flying and pollution to the mirror surface are prevented; when the forming shaft 2 rises on the platform, the volume of the forming cavity 1 is reduced, the pressure is increased, the pressure-stabilizing exhaust valve V6 is frequently opened and closed, and the pressure of the regulating system reaches a set value and is accompanied with the generation of exhaust.
After the equipment is prepared in the earlier stage, inert gas is filled to perform gas replacement, a button of a gas replacement controller is started, an air inlet valve V2 of the dust removal cabinet is opened, an air outlet valve V5 of the dust removal cabinet is opened, an air replacement air inlet valve V3 is opened, an air replacement air outlet valve V7 is opened, and a cavity oxygen sensor SO is formed 2 The detection value is gradually reduced, the fan 6 is started, and when the detection value of the oxygen sensor is lower than the required value, the air inlet valve, the air outlet valve, the air replacement inlet valve and the air replacement outlet valve of the dust removal cabinet are closed; when the oxygen content increases and exceeds the required value due to any reason, the valve is restarted to perform gas replacement.
After the gas replacement process is finished, the forming process is started, referring to fig. 3, when the feedback value of the differential pressure sensor S delta P of the filter element is increased due to long-time use of the filter element 5, a button of the differential pressure adjusting controller is started, the variable frequency value of the fan is automatically adjusted by the differential pressure adjusting controller to be increased, the air quantity is ensured to be unchanged, the influence of the blockage of the filter element on the forming process is eliminated, and the forming process is ended. If the differential pressure of the filter element reaches the alarm value during the forming process, the forming process is stopped, and the filter element is replaced and the forming process is newly equipped.
In the whole equipment forming process, the equipment is always in the state of pressure stabilization, low oxygen content and differential pressure automatic compensation, and the changes of the pressure value, the oxygen content value and the differential pressure value of the forming cavity 1 caused by any reasons are compensated, so that the automatic control of the gas replacement unit, the pressure stabilization unit and the differential pressure regulating unit is realized.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments may be modified or some or all of the technical features may be replaced equivalently, and these modifications or replacements do not make the essence of the corresponding technical scheme deviate from the scope of the technical scheme of the embodiments of the present invention.
Claims (9)
1. An atmosphere control system of an additive manufacturing laser forming device, which is characterized in that: comprising the following steps:
the inert gas replacement unit is used for calculating the required replacement gas amount according to the volume of the communication space of the forming area and the set oxygen content and controlling gas replacement in the forming cavity;
the pressure stabilizing unit is used for adjusting the pressure in the forming cavity in the forming process;
the differential pressure adjusting unit is used for adjusting the blowing air quantity in the forming process; the inert gas displacement unit comprises a gas displacement controller;
and connected to the gas displacement controller: the device comprises a dust removal cabinet air inlet valve, a dust removal cabinet air outlet valve, a gas replacement air inlet valve and a gas replacement air outlet valve, which are respectively controlled into a first flow control valve, a second flow control valve, a third flow control valve and a fourth flow control valve of the air inlet flow of a cavity, a powder collection groove, a forming shaft and the dust removal cabinet, an electronic flowmeter for measuring the total air inlet amount in the whole gas replacement process, and an oxygen sensor for detecting the oxygen content of the gas in the forming cavity; the air inlet valve, the flow control valve IV, the dust removing cabinet and the air outlet valve of the dust removing cabinet are sequentially connected, the air replacement air inlet valve, the flow control valve I, the forming cavity body and the air replacement air outlet valve are sequentially connected, the air replacement air inlet valve, the flow control valve II and the powder collecting groove are sequentially connected, the air replacement air inlet valve, the flow control valve III and the forming shaft are sequentially connected, and the electronic flowmeter is respectively connected with the air replacement air inlet valve and the air inlet valve of the dust removing cabinet.
2. The additive manufacturing laser forming apparatus atmosphere control system according to claim 1, wherein: the voltage stabilizing unit comprises a voltage stabilizing controller;
and the voltage stabilizing controller is connected with: the pressure stabilizing air inlet valve, the pressure stabilizing air outlet valve, an electronic pressure regulating valve for controlling the pressure in the forming cavity and a pressure sensor for detecting the pressure in the forming cavity; the pressure stabilizing air inlet valve, the electronic pressure regulating valve, the optical system lens group, the forming cavity and the pressure stabilizing air outlet valve are sequentially connected.
3. The additive manufacturing laser forming apparatus atmosphere control system according to claim 1, wherein: the differential pressure regulating unit comprises a differential pressure regulating controller;
and connected to the differential pressure regulator controller: a differential pressure sensor for detecting differential pressure between the filter element and the air inlet pipe, and a frequency converter of the fan.
4. The additive manufacturing laser forming apparatus atmosphere control system according to claim 1, wherein: the dust removal device also comprises an exhaust filter which is respectively connected with the exhaust valve of the dust removal cabinet, the exhaust valve of the gas replacement and the pressure stabilizing exhaust valve.
5. The additive manufacturing laser forming apparatus atmosphere control system according to claim 1, wherein: the electronic flowmeter is arranged on an inert gas inlet main pipeline of the whole control system, and a manual control main valve and a pressure regulating valve are further arranged on the main pipeline at the inert gas inlet.
6. An atmosphere control method for an additive manufacturing laser forming apparatus using the atmosphere control system according to any one of claims 1 to 5, characterized in that: the method comprises the following steps:
1) And (3) controlling a voltage stabilizing unit: maintaining the system pressure at a set point;
2) And controlling an inert gas replacement unit: filling inert gas into the communication space needing gas replacement for gas replacement by opening the gas inlet and outlet control valve, detecting the gas oxygen content in the molding cavity by using an oxygen sensor, and closing the gas inlet and outlet control valve when the gas oxygen content reaches a threshold value;
3) Control differential pressure regulating unit: and detecting the air quantity in the forming cavity in the forming process, and adjusting a frequency converter of the fan to control the fan when the air quantity changes, so as to ensure that the air quantity is unchanged.
7. The atmosphere control method of an additive manufacturing laser forming apparatus according to claim 6, characterized in that: the specific process of the step 1) is as follows: sealing the molding cavity, inputting a required pressure value, opening a pressure stabilizing controller button, opening a pressure stabilizing air inlet valve and an electronic pressure regulating valve, enabling the system to reach the required pressure, and closing the pressure stabilizing air inlet valve and the electronic pressure regulating valve; debugging the forming shaft and the powder scraping device, when the forming shaft platform descends, the forming cavity volume increases, the pressure decreases, the pressure stabilizing air inlet valve is opened, the electronic pressure regulating valve is opened, and the regulating system pressure reaches a set value; when the forming shaft platform rises, the volume of the forming cavity is reduced, the pressure rises, the pressure-stabilizing exhaust valve is frequently opened and closed, and the pressure of the regulating system reaches a set value and is accompanied with the generation of exhaust.
8. The atmosphere control method of an additive manufacturing laser forming apparatus according to claim 6, characterized in that: the specific process of the step 2) is as follows: opening a button of a gas replacement controller, opening an air inlet valve of the dust removal cabinet, opening an air outlet valve of the dust removal cabinet, opening the air inlet valve of the gas replacement, opening the air outlet valve of the gas replacement, gradually reducing the detection value of an oxygen sensor of a molding cavity, opening a fan, and closing the air inlet valve of the dust removal cabinet, the air outlet valve of the dust removal cabinet, the air inlet valve of the gas replacement and the air outlet valve of the gas replacement when the detection value of the oxygen sensor is lower than a required value; when the oxygen content increases and exceeds the required value due to any reason, the valve is restarted to perform gas replacement.
9. The atmosphere control method of an additive manufacturing laser forming apparatus according to claim 6, characterized in that: the specific process of the step 3) is as follows: when the feedback value of the differential pressure sensor of the filter element is increased due to long-time use of the filter element, a button of the differential pressure adjusting controller is started, the differential pressure adjusting controller automatically adjusts the variable frequency value of the fan to be increased, the air quantity is ensured to be unchanged, and the forming process is finished; if the differential pressure of the filter element reaches the alarm value during the forming process, the forming process is stopped, and the filter element is replaced and the forming process is newly equipped.
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| CN202311249632.7A CN117696919A (en) | 2018-09-21 | 2018-09-21 | Atmosphere control method of additive manufacturing laser forming equipment |
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| CN114309668B (en) * | 2021-12-10 | 2024-05-31 | 湖南云箭集团有限公司 | Oxygen pressure regulating and controlling system and method suitable for metal additive manufacturing equipment |
| CN114713858B (en) * | 2022-03-18 | 2023-01-10 | 成都飞机工业（集团）有限责任公司 | Inert gas seal box circulation system and use method |
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Denomination of invention: An atmosphere control system and method for additive manufacturing laser forming equipment Granted publication date: 20231027 Pledgee: Bank of China Tianjin Heping Branch Pledgor: TIANJIN RADIUM LASER TECHNOLOGY Co.,Ltd. Registration number: Y2024980010582 |