Device and method for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment

Abstract

The present invention discloses a device and method for collecting characteristic parameters of focusing current of electron beam additive manufacturing equipment, including a receiving component arranged in a vacuum chamber of the electron beam additive manufacturing equipment and a signal processing system outside the vacuum chamber. The receiving component is composed of two brackets, namely a feeding bracket and a receiving bracket, two horizontal rollers, namely a feeding horizontal axis and a receiving horizontal axis, two reels, namely a feeding reel and a receiving reel, a metal film, a reel motor and a beam receiving metal plate. When the electron beam emitted by the electron beam additive manufacturing equipment breaks through the metal film of the working section and irradiates the beam receiving metal plate, the electrons irradiated on the beam receiving metal plate form a current signal which is introduced into the signal processing system. The present invention uses a metal film as an electron beam cutoff material, and obtains the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment by collecting the time when the electron beam breaks through the metal film. The present invention has the characteristics of simple structure, adjustable applicable collection range and simple operation.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a device and method for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment. Background Art

[0002] In recent years, additive manufacturing technology has made great progress and has been widely used in aerospace, biomedicine and other fields. With the high-end application fields, various industries have higher and higher requirements for additive manufacturing products, which also puts forward higher process requirements for electron beam additive manufacturing equipment.

[0003] Electron beam additive manufacturing equipment has the characteristics of high energy absorption rate, low pollution and high material utilization rate, so it is widely used in industrial production. Using single electron gun electron beam additive manufacturing equipment to form large-sized parts requires increasing the deflection angle of the electron beam to expand the scanning range of the electron beam, but increasing the deflection angle will cause the electron beam to defocus and affect the melting effect of the metal powder, thereby affecting the forming accuracy of the parts. Therefore, it is necessary to collect the focusing current characteristic parameters in the working plane to correct the focusing current of the electron beam additive manufacturing equipment when it is working.

[0004] The traditional method for collecting the focusing current characteristic parameters of electron beam additive manufacturing equipment is to observe the brightness of the electron beam spot to determine whether the electron beam focus falls on the characteristic parameter point, thereby obtaining the focusing current characteristic parameters. However, since this method of collecting focusing current characteristic parameters requires subjective observation by the human eye, it is highly subjective. Summary of the invention

[0005] The present invention aims to solve the subjective problem brought about by the traditional focusing current characteristic parameter collection device, and provides a focusing current characteristic parameter collection device and method for electron beam additive manufacturing equipment, which has the characteristics of simple structure, adjustable collection range and simple operation.

[0006] To solve the above problems, the present invention is achieved through the following technical solutions:

[0007] A device for collecting characteristic parameters of focusing current of an electron beam additive manufacturing device, comprising a receiving component arranged in a vacuum chamber of the electron beam additive manufacturing device and a signal processing system arranged outside the vacuum chamber of the electron beam additive manufacturing device;

[0008] The receiving assembly consists of two brackets, namely a feeding bracket and a receiving bracket, two horizontal rollers, namely a feeding horizontal axis and a receiving horizontal axis, two reels, namely a feeding reel and a receiving reel, a metal film, a winding motor and a beam receiving metal plate; the feeding bracket and the receiving bracket are arranged opposite to each other, and there is a certain distance between them; the feeding reel and the feeding horizontal axis are installed on the feeding bracket, and the feeding horizontal axis is located directly above the feeding reel; the receiving reel and the receiving horizontal axis are installed on the receiving bracket, and the receiving horizontal axis is located directly above the motor; the central axes of the feeding reel, the receiving reel, the feeding horizontal axis and the receiving horizontal axis are parallel to each other; the central axes of the feeding horizontal axis and the receiving horizontal axis are at the same horizontal height; one end of the metal film is fixed on the feeding reel, and the other end of the metal film is fixed on the receiving reel via the feeding horizontal axis and the receiving horizontal axis in sequence; the metal film between the feeding horizontal axis and the receiving horizontal axis That is, the copper mold of the working section is kept in a horizontal state, and the upper surface of the metal film of the working section coincides with the working plane of the working platform of the electron beam additive manufacturing equipment; the coverage area of ​​the metal film of the working section is the electron beam scanning working area of ​​the electron beam additive manufacturing equipment; the output shaft of the winding motor is connected to the receiving reel, and when the winding motor drives the receiving reel to rotate, the copper mold wound on the feeding reel passes through the feeding horizontal axis and the receiving horizontal axis, and is wound on the receiving reel; the beam receiving metal plate is made of conductive metal and is placed directly below the metal film of the working section; the beam receiving metal plate is electrically isolated from the inner wall of the vacuum chamber of the electron beam additive manufacturing equipment; the beam receiving metal plate is connected to the signal processing system through a wire, and when the electron beam emitted by the electron beam additive manufacturing equipment breaks through the metal film of the working section and irradiates the beam receiving metal plate, the electrons irradiated on the beam receiving metal plate form a current signal which is introduced into the signal processing system.

[0009] In the above solution, an insulating gasket is provided at the bottom of the beam receiving metal plate.

[0010] In the above scheme, the shapes and sizes of the feeding horizontal axis and the receiving horizontal axis are exactly the same.

[0011] In the above scheme, the central axes of the feeding reel and the receiving reel are at the same horizontal height.

[0012] In the above solution, the overall thickness of the metal film is consistent.

[0013] The method for collecting the focusing current characteristic parameters of the electron beam additive manufacturing equipment implemented by the above device comprises the following steps:

[0014] Step 1: Keep the deflection current of the electron beam additive manufacturing equipment always at (0,0), and determine the focusing current I corresponding to the minimum electron beam spot on the working plane of the working platform by visual observation. f0 ′, and in this focusing current I f0′, by increasing and decreasing the focusing current of the electron beam additive manufacturing equipment in steps, and using the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment to carry out multiple copper mold breakdown experiments, the fitting curves of each focusing current and the corresponding breakdown time are obtained. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I under the deflection current of (0,0) f0 ;

[0015] Step 2: Calculate the deflection current (I pxi ,I pyi ), so that the focus of the electron beam of the electron beam additive manufacturing device can fall on the corresponding characteristic parameter point on the working plane under the control of each deflection current;

[0016] Step 3: For each characteristic parameter point, the deflection current (I pxi ,I pyi ), keep the deflection current of the electron beam additive manufacturing equipment always at (I pxi ,I pyi ), and the optimal focusing current I when the deflection current is (0,0) f0 On the basis of the above, the focusing current of the electron beam additive manufacturing equipment is gradually reduced, and the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment is used to perform multiple copper mold breakdown experiments to obtain the fitting curves of each focusing current and the corresponding breakdown time. The focusing current corresponding to the valley value of the fitting curve is the deflection current (I pxi ,I pyi ) under the optimal focusing current I fi ;

[0017] In the above, i=,1,2,…,I, where I is the number of sampling points of the deflection current.

[0018] The specific process of step 1 above is as follows:

[0019] Step 1.1, start the electron beam additive manufacturing equipment first; then observe the size of the electron beam spot on the working plane of the working platform of the electron beam additive manufacturing equipment with the naked eye, and record the focusing current I corresponding to the smallest electron beam spot f0 '; then stop the electron beam additive manufacturing equipment;

[0020] Step 1.2, remove the working platform, and respectively place the receiving component and the signal processing system of the electron beam additive manufacturing equipment focusing current characteristic parameter collection device outside the vacuum chamber and outside the vacuum chamber of the electron beam additive manufacturing equipment, and connect the receiving component and the signal processing system with a wire; at the same time, ensure that the upper surface of the working section metal film coincides with the working plane of the working platform of the electron beam additive manufacturing equipment;

[0021] Step 1.3: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 ', the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0022] Step 1.4: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 'The breakdown time t0 from this start to this shutdown;

[0023] Step 1.5, initialize the number of iterations k = 1;

[0024] Step 1.6, start the coiling motor of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor drives the receiving reel to rotate, and drives the feeding reel to rotate through the metal film, and the metal film in the working section between the feeding horizontal axis and the receiving horizontal axis moves horizontally from the feeding side to the receiving side by a certain distance;

[0025] Step 1.7, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the electron beam additive manufacturing equipment focusing current to I f0 After ′-kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0026] Step 1.8: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 The breakdown time t from this start to this shutdown under ′-k×Δ -k ;

[0027] Step 1.9, start the coiling motor of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor drives the receiving reel to rotate, and drives the feeding reel to rotate through the metal film, and the metal film in the working section between the feeding horizontal axis and the receiving horizontal axis moves horizontally from the feeding side to the receiving side by a certain distance;

[0028] Step 1.10: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 After ′+kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0029] Step 1.11. The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 The breakdown time t from this start to this shutdown under ′+k×Δ k ;

[0030] Step 1.12: Set the number of iterations to k+1, and repeat steps 1.6-1.11 until k=K0, thereby obtaining the focusing current I f0 ′-K0Δ,…,I f0 ′-2Δ,I f0 ′-Δ,I f0 ′,I f0 ′+Δ,I f0 ′+2Δ,…,I f0 The corresponding breakdown time under ′+K0Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I when the deflection current is (0,0). f0 ;

[0031] The above K0 is the number of sampling points of the focusing current under the deflection current (0,0); Δ is the unit step amount of the focusing current.

[0032] The specific process of step 3 above is as follows:

[0033] Step 3.1, initialize the number of iterations k = 1;

[0034] Step 3.2, start the coiling motor of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor drives the receiving reel to rotate, and drives the feeding reel to rotate through the metal film, and the metal film in the working section between the feeding horizontal axis and the receiving horizontal axis moves horizontally from the feeding side to the receiving side by a certain distance;

[0035] Step 3.3, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0-kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0036] Step 3.4: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 -k×ΔThe breakdown time t from this start to this shutdown k ;

[0037] Step 3.5: Set the number of iterations to k+1 and repeat steps 3.1-3.4 until k=K i , thus obtaining the focusing current I f0 -Δ,I f0 -2Δ,…,I f0 -K i K breakdown times corresponding to Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the current deflection current (I pxi ,I qyi ) under the optimal focusing current I fi ;

[0038] In the above, i=,1,2,…,I, where I is the number of sampling points of the deflection current; K i is the deflection current (I pxi ,I qyi ) is the number of sampling points of the focusing current; Δ is the unit step size of the focusing current.

[0039] Compared with the prior art, the present invention uses a metal film as an electron beam cutoff material, and obtains the focusing current characteristic parameters of the electron beam additive manufacturing equipment by collecting the time when the electron beam breaks through the metal film. The traditional slope-molten pool extreme value method can only measure the focal position of the electron beam vertically directed to the working plane, and then obtain the focusing current parameters of the electron beam additive manufacturing equipment. The present invention can measure the focal position after the electron beam is deflected, and then collect the focusing current characteristic parameters after the electron beam is deflected. Compared with the method of using a Faraday cup to determine the optimal focusing current of an electron beam additive manufacturing equipment, the device of the present invention has a simple structure, a low technical threshold, convenient measurement steps, and low consumables costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a structural diagram of a focusing current characteristic parameter collection device for electron beam additive manufacturing equipment.

[0041] Figure 2 for Figure 1 Schematic diagram of the installation in the electron beam additive manufacturing equipment.

[0042] Numbers in the figure: 1. Feeding bracket; 2. Receiving bracket; 3. Feeding horizontal axis; 4. Receiving horizontal axis; 5. Feeding reel; 6. Receiving reel; 7. Metal film; 8. Reeling motor; 9. Beam receiving metal plate; 10. Insulating gasket. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific examples.

[0044] See also Figure 1 , a device for collecting characteristic parameters of focusing current of an electron beam additive manufacturing device, comprising a receiving component arranged in a vacuum chamber of the electron beam additive manufacturing device and a signal processing system arranged outside the vacuum chamber of the electron beam additive manufacturing device.

[0045] The receiving assembly is composed of two brackets, namely a feeding bracket 1 and a receiving bracket 2, two horizontal rollers, namely a feeding horizontal axis 3 and a receiving horizontal axis 4, two reels, namely a feeding reel 5 and a receiving reel 6, a metal film 7, a reel motor 8 and a beam receiving metal plate 9, as shown in FIG. Figure 2As shown. The feeding bracket 1 and the receiving bracket 2 are arranged opposite to each other, and there is a certain distance between them. The feeding reel 5 and the feeding horizontal axis 3 are installed on the feeding bracket 1, and the feeding horizontal axis 3 is located directly above the feeding reel 5. The receiving reel 6 and the receiving horizontal axis 4 are installed on the receiving bracket 2, and the receiving horizontal axis 4 is located directly above the motor. The central axes of the feeding reel 5, the receiving reel 6, the feeding horizontal axis 3 and the receiving horizontal axis 4 are parallel to each other. The central axes of the feeding horizontal axis 3 and the receiving horizontal axis 4 are at the same horizontal height. One end of the metal film 7 is fixed on the feeding reel 5, and the other end of the metal film 7 is fixed on the receiving reel 6 via the feeding horizontal axis 3 and the receiving horizontal axis 4. The metal film 7 between the feeding horizontal axis 3 and the receiving horizontal axis 4, that is, the working section copper mold, remains in a horizontal state, and the upper surface of the working section metal film 7 coincides with the working plane of the electron beam spot during the forming process of the electron beam additive manufacturing equipment, that is, the working plane of the working platform. According to the size of the electron beam additive manufacturing equipment, the distance between the two reels of the collection equipment can be freely adjusted, but it should not be too large. The center drop of the metal film 7 will affect the experimental data. If the parameter collection area is too large, the focusing current characteristic parameters in the working area can be collected by the partition collection method. In order to ensure the consistency of the breakdown time, the overall thickness of the metal film 7 is consistent. In the preferred embodiment of the present invention, the metal film 7 adopts a 0.2mm thick copper film or aluminum film. In order to ensure the level of the working section metal film 7, in the preferred embodiment of the present invention, the shape and size of the feeding horizontal axis 3 and the receiving horizontal axis 4 are exactly the same, and the central axis of the feeding reel 5 and the receiving reel 6 are at the same horizontal height. The coverage area of ​​the working section metal film 7 is the electron beam scanning working area of ​​the electron beam additive manufacturing equipment. The output shaft of the coiling motor 8 is connected to the receiving reel 6. When the coiling motor 8 drives the receiving reel 6 to rotate, the copper mold wound on the feeding reel 5 passes through the feeding horizontal axis 3 and the receiving horizontal axis 4, and is wound on the receiving reel 6. The beam receiving metal plate 9 is made of a conductive metal and is placed directly below the working section metal film 7. In a preferred embodiment of the present invention, the beam receiving metal plate 9 is a stainless steel plate. An insulating gasket 10 is provided at the bottom of the beam receiving metal plate 9, and the beam receiving metal plate 9 is electrically isolated from the inner wall of the vacuum chamber of the electron beam additive manufacturing device. In a preferred embodiment of the present invention, the insulating gasket 10 is a ceramic gasket.

[0046] The present invention cooperates with the coiling motor 8 and the reel to bring about a one-way transmission to move the metal film 7 horizontally, and uses the beam receiving metal plate 9 below the metal film 7 to receive the electron beam signal. Then, the signal processing system processes the electrical signal received by the beam receiving metal plate 9 to obtain the time when the electron beam breaks through the metal film 7, and the focusing current characteristic parameters of the electron beam additive manufacturing device are obtained by the time of breaking through the metal film 7. When the electron beam emitted by the electron beam additive manufacturing device breaks through the metal film 7, it will irradiate the beam receiving metal plate 9. Since the insulating gasket 10 isolates the beam receiving metal plate 9 from the inner wall of the vacuum chamber, the electrons irradiated on the beam receiving metal plate 9 form a current signal which is introduced into the signal processing system and processed by the signal processing system. The signal processing system is used to process the current signal collected on the beam receiving metal plate 9, and the time signal of the current signal received by the beam receiving metal plate 9 is used as a judgment signal for the optimal focusing current of the electron beam additive manufacturing device. In order to ensure that the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment can accurately record the time of each startup and shutdown of the electron beam additive manufacturing equipment, the beam receiving metal plate 9 is connected to the start and shutdown control of the electron beam additive manufacturing equipment through a wire. By adjusting the deflection current, multiple traversal experiments are carried out. In each experiment, the signal processing system starts timing when the electron beam is emitted. When the peak value of the electrical signal received by the beam receiving metal plate 9 appears, the signal processing system stops timing, thereby obtaining each breakdown time. The breakdown time is used to draw a fitting curve under the current deflection current. When the peak time collected is the shortest, it is determined that the focusing current of the device at this time is the optimal focusing current under the deflection angle.

[0047] The method for collecting focusing current characteristic parameters of an electron beam additive manufacturing device implemented by the above device comprises the following steps:

[0048] Step 1: Keep the deflection current of the electron beam additive manufacturing equipment always at (0,0), and determine the focusing current I corresponding to the minimum electron beam spot on the working plane of the working platform by visual observation. f0 ′, and in this focusing current I f0 ′, by increasing and decreasing the focusing current of the electron beam additive manufacturing equipment in steps, and using the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment to carry out multiple copper mold breakdown experiments, the fitting curves of each focusing current and the corresponding breakdown time are obtained. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I under the deflection current of (0,0) f0 ;

[0049] Step 1.1, start the electron beam additive manufacturing equipment first; then observe the size of the electron beam spot on the working plane of the working platform of the electron beam additive manufacturing equipment with the naked eye, and record the focusing current I corresponding to the smallest electron beam spot f0 '; then stop the electron beam additive manufacturing equipment;

[0050] Step 1.2, remove the working platform, and respectively place the receiving component and the signal processing system of the electron beam additive manufacturing equipment focusing current characteristic parameter collection device outside the vacuum chamber and outside the vacuum chamber of the electron beam additive manufacturing equipment, and connect the receiving component and the signal processing system with a wire; at the same time, ensure that the upper surface of the working section metal film 7 coincides with the working plane of the working platform of the electron beam additive manufacturing equipment; see Figure 2 ;

[0051] Step 1.3: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 ', the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0052] Step 1.4: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate 9 of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 'The breakdown time t0 from this start to this shutdown;

[0053] Step 1.5, initialize the number of iterations k = 1;

[0054] Step 1.6, start the coiling motor 8 of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor 8 drives the receiving reel 6 to rotate, and drives the feeding reel 5 to rotate through the metal film 7, and the metal film 7 in the working section between the feeding horizontal axis 3 and the receiving horizontal axis 4 moves horizontally from the feeding side to the receiving side by a certain distance;

[0055] Step 1.7, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the electron beam additive manufacturing equipment focusing current to I f0 After ′-kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0056] Step 1.8, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate 9 of the receiving component in real time, and turns off the electron beam additive manufacturing equipment when the electrical signal reaches the peak value and remains stable. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0The breakdown time t from this start to this shutdown under ′-k×Δ -k ;

[0057] Step 1.9, start the coiling motor 8 of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor 8 drives the receiving reel 6 to rotate, and drives the feeding reel 5 to rotate through the metal film 7, and the metal film 7 in the working section between the feeding horizontal axis 3 and the receiving horizontal axis 4 moves horizontally from the feeding side to the receiving side by a certain distance;

[0058] Step 1.10: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 After ′+kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0059] Step 1.11, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate 9 of the receiving component in real time, and turns off the electron beam additive manufacturing equipment when the electrical signal reaches the peak value and remains stable. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 The breakdown time t from this start to this shutdown under ′+k×Δ k ;

[0060] Step 1.12: Set the number of iterations to k+1, and repeat steps 1.6-1.11 until k=K0, thereby obtaining the focusing current I f0 ′-K0Δ,…,I f0 ′-2Δ,I f0 ′-Δ,I f0 ′,I f0 ′+Δ,I f0 ′+2Δ,…,I f0 The corresponding breakdown time under ′+K0Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I when the deflection current is (0,0). f0 ;

[0061] Step 2: Calculate the deflection current (I pxi ,I pyi ), so that the focus of the electron beam of the electron beam additive manufacturing device can fall on the corresponding characteristic parameter point on the working plane under the control of each deflection current; wherein (I pxi ,I pyi )≠(0,0);

[0062] Step 3: For each characteristic parameter point, the deflection current (I pxi ,I pyi ), keep the deflection current of the electron beam additive manufacturing equipment always at (I pxi ,I pyi ), and the optimal focusing current I when the deflection current is (0,0) f0 On the basis of the above, the focusing current of the electron beam additive manufacturing equipment is gradually reduced, and the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment is used to perform multiple copper mold breakdown experiments to obtain the fitting curves of each focusing current and the corresponding breakdown time. The focusing current corresponding to the valley value of the fitting curve is the deflection current (I pxi ,I pyi ) under the optimal focusing current I fi ;

[0063] Step 3.1, initialize the number of iterations k = 1;

[0064] Step 3.2, start the coiling motor 8 of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor 8 drives the receiving reel 6 to rotate, and drives the feeding reel 5 to rotate through the metal film 7, and the metal film 7 in the working section between the feeding horizontal axis 3 and the receiving horizontal axis 4 moves horizontally from the feeding side to the receiving side by a certain distance;

[0065] Step 3.3, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 -kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing;

[0066] Step 3.4: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate 9 of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 -k×ΔThe breakdown time t from this start to this shutdown k ;

[0067] Step 3.5: Set the number of iterations to k+1 and repeat steps 3.1-3.4 until k=K i , thus obtaining the focusing current I f0 -Δ,I f0 -2Δ,…,I f0 -Ki K breakdown times corresponding to Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the current deflection current (I pxi ,I qyi ) under the optimal focusing current I fi ;

[0068] In the above i=,1,2,…,I, I is the number of sampling points of the deflection current; in the present invention, the value of the number of sampling points I of the deflection current is determined by the number of characteristic parameter points, and the number of sampling points I of the deflection current is equal to the number of characteristic parameter points. K0 is the number of sampling points of the focusing current under the deflection current (0,0); K i is the deflection current (I pxi ,I qyi ) under the focusing current sampling point number; In the present invention, the focusing current sampling point number K0 and K under different deflection currents i The value of needs to be large enough, that is, it is necessary to ensure that the breakdown time has a valley value during the sampling process. Under the same deflection current, the focusing current is changed, and the breakdown time fitting curve is a quadratic curve with an opening upward. The focusing current value corresponding to the valley value of the fitting curve is the optimal focusing current. Due to the influence of human subjective factors, I under the deflection current (0,0) f0 The value of ' may appear on the left or right side of the valley value of the fitting curve, so it is necessary to f0 'Incremental breakdown test and decremental breakdown test are performed to find the valley value of the fitting curve and obtain the accurate optimal focusing current I f0 According to existing experiments, as the deflection current increases, the best focusing current decreases, so other deflection currents (I pxi ,I qyi ) will be larger than the optimal focusing current I corresponding to the deflection current (0,0). f0 Small, only need to be in I f0 Based on this, the optimal focusing current value under other different deflections can be obtained by conducting a reduction breakdown experiment. For convenience, in this embodiment, K0, K1, ... K I Δ is the unit step size of the focusing current. In this embodiment, the unit step size Δ of the focusing current is 0.1 mA.

[0069] The principle of the present invention is: the device is installed in the vacuum working chamber of the rapid prototyping device, the upper surface of the metal film 7 coincides with the working plane of the electron beam additive manufacturing device when forming 3D parts, the beam receiving metal plate 9 is placed under the metal film 7, the beam receiving metal plate 9 is electrically isolated from the outer wall of the rapid prototyping device by a ceramic gasket, and the signal on the beam receiving metal plate 9 is led out by a wire. The deflection current I of the x-axis is controlled by the central controller of the rapid prototyping device px , the deflection current I of the y-axis py , so that the electron beam focus moves to a certain characteristic point. By fine-tuning the focusing current I at the position of a certain characteristic point f The metal film 7 is repeatedly punched, and when the time from beam emission to the beam receiving metal plate 9 receiving the electrical signal is the shortest, the focusing current at this time is the optimal focusing current for the characteristic point.

[0070] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A device for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment, characterized in that: It includes a receiving component arranged in a vacuum chamber of the electron beam additive manufacturing equipment and a signal processing system arranged outside the vacuum chamber of the electron beam additive manufacturing equipment; The receiving assembly is composed of two brackets, namely a feeding bracket (1) and a receiving bracket (2), two horizontal rollers, namely a feeding horizontal axis (3) and a receiving horizontal axis (4), two reels, namely a feeding reel (5) and a receiving reel (6), a metal film (7), a reel motor (8) and a beam receiving metal plate (9); the feeding bracket (1) and the receiving bracket (2) are arranged opposite to each other, and there is a certain distance between them; the feeding reel (5) and the feeding horizontal axis (3) are installed on the feeding bracket (1), and the feeding horizontal axis (3) is located directly above the feeding reel (5); the receiving reel (6) and the receiving reel The horizontal axis (4) is installed on the receiving bracket (2), and the receiving horizontal axis (4) is located directly above the motor; the central axes of the feeding reel (5), the receiving reel (6), the feeding horizontal axis (3) and the receiving horizontal axis (4) are parallel to each other; the central axes of the feeding horizontal axis (3) and the receiving horizontal axis (4) are at the same horizontal height; the overall thickness of the metal film (7) is consistent, one end of the metal film (7) is fixed on the feeding reel (5), and the other end of the metal film (7) is fixed on the receiving reel (6) via the feeding horizontal axis (3) and the receiving horizontal axis (4) in sequence; the feeding horizontal axis (3) and the receiving horizontal axis (4) are parallel to each other ... The metal film (7) between the axis (3) and the receiving horizontal axis (4), i.e., the copper mold of the working section, is kept in a horizontal state, and the upper surface of the metal film (7) of the working section coincides with the working plane of the working platform of the electron beam additive manufacturing equipment; the coverage area of ​​the metal film (7) of the working section is the electron beam scanning working area of ​​the electron beam additive manufacturing equipment; the output shaft of the winding motor (8) is connected to the receiving reel (6), and when the winding motor (8) drives the receiving reel (6) to rotate, the copper mold wound on the feeding reel (5) passes through the feeding horizontal axis (3) and the receiving horizontal axis (4), and is wound on the receiving reel (6) The beam receiving metal plate (9) is made of conductive metal and is placed directly below the working section metal film (7); an insulating gasket (10) is provided at the bottom of the beam receiving metal plate (9), and the beam receiving metal plate (9) is electrically isolated from the inner wall of the vacuum chamber of the electron beam additive manufacturing equipment; the beam receiving metal plate (9) is connected to the signal processing system through a wire, and when the electron beam emitted by the electron beam additive manufacturing equipment breaks through the working section metal film (7) and irradiates the beam receiving metal plate (9), the electrons irradiated onto the beam receiving metal plate (9) form a current signal that is introduced into the signal processing system.

2. The device for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment according to claim 1, characterized in that: The shapes and sizes of the feeding horizontal axis (3) and the receiving horizontal axis (4) are exactly the same.

3. The device for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment according to claim 2, characterized in that: The central axes of the feeding reel (5) and the receiving reel (6) are at the same horizontal height.

4. A method for collecting characteristic parameters of focusing current of an electron beam additive manufacturing device implemented by the device of claim 1, characterized in that: The steps include: Step 1: Keep the deflection current of the electron beam additive manufacturing equipment always at (0,0), and determine the focusing current I corresponding to the minimum electron beam spot on the working plane of the working platform by visual observation. f0 ′, and in this focusing current I f0 ′, by increasing and decreasing the focusing current of the electron beam additive manufacturing equipment in steps, and using the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment to carry out multiple copper mold breakdown experiments, the fitting curves of each focusing current and the corresponding breakdown time are obtained. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I under the deflection current of (0,0) f0 ; Step 2: Calculate the deflection current (I pxi ,I pyi ), so that the focus of the electron beam of the electron beam additive manufacturing device can fall on the corresponding characteristic parameter point on the working plane of the working platform under the control of each deflection current; Step 3: For each characteristic parameter point, the deflection current (I pxi ,I pyi ), keep the deflection current of the electron beam additive manufacturing equipment always at (I pxi ,I pyi ), and the deflection current obtained in step 1 is the optimal focusing current I under (0,0) f0 On the basis of the above, the focusing current of the electron beam additive manufacturing equipment is gradually reduced, and the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment is used to perform multiple copper mold breakdown experiments to obtain the fitting curves of each focusing current and the corresponding breakdown time. The focusing current corresponding to the valley value of the fitting curve is the deflection current (I pxi ,I pyi ) under the optimal focusing current I fi ; In the above, i=,1,2,…,I, where I is the number of sampling points of the deflection current.

5. The method for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment according to claim 4, characterized in that: The specific process of step 1 is as follows: Step 1.1, start the electron beam additive manufacturing equipment first; then observe the size of the electron beam spot on the working plane of the working platform of the electron beam additive manufacturing equipment with the naked eye, and record the focusing current I corresponding to the smallest electron beam spot f0 '; then stop the electron beam additive manufacturing equipment; Step 1.2, remove the working platform, and respectively place the receiving component and the signal processing system of the electron beam additive manufacturing equipment focusing current characteristic parameter collection device outside the vacuum chamber and outside the vacuum chamber of the electron beam additive manufacturing equipment, and connect the receiving component and the signal processing system with a wire; at the same time, ensure that the upper surface of the working section metal film (7) coincides with the working plane of the working platform of the electron beam additive manufacturing equipment; Step 1.3: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 ', the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing; Step 1.4, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate (9) of the receiving component in real time, and turns off the electron beam additive manufacturing equipment when the electrical signal reaches a peak value and remains stable. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 'The breakdown time t0 from this start to this shutdown; Step 1.5, initialize the number of iterations k = 1; Step 1.6, start the coiling motor (8) of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor (8) drives the receiving reel (6) to rotate, and drives the feeding reel (5) to rotate through the metal film (7), and the metal film (7) of the working section between the feeding horizontal axis (3) and the receiving horizontal axis (4) moves horizontally from the feeding side to the receiving side by a certain distance; Step 1.7, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the electron beam additive manufacturing equipment focusing current to I f0 After ′-kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing; Step 1.8, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate (9) of the receiving component in real time, and turns off the electron beam additive manufacturing equipment when the electrical signal reaches a peak value and remains stable. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 The breakdown time t from this start to this shutdown under ′-k×Δ -k ; Step 1.9, start the coiling motor (8) of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor (8) drives the receiving reel (6) to rotate, and drives the feeding reel (5) to rotate through the metal film (7), and the metal film (7) of the working section between the feeding horizontal axis (3) and the receiving horizontal axis (4) moves horizontally from the feeding side to the receiving side by a certain distance; Step 1.10: First, start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 After ′+kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing; Step 1.11, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate (9) of the receiving component in real time, and turns off the electron beam additive manufacturing equipment when the electrical signal reaches a peak value and remains stable. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 The breakdown time t from this start to this shutdown under ′+k×Δ k ; Step 1.12: Set the number of iterations to k+1, and repeat steps 1.6-1.11 until k=K0, thereby obtaining the focusing current I f0 ′-K0Δ,…,I f0 ′-2Δ,I f0 ′-Δ,I f0 ′,I f0 ′+Δ,I f0 ′+2Δ,…,I f0 The corresponding breakdown time under ′+K0Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the optimal focusing current I when the deflection current is (0,0). f0 ; The above K0 is the number of sampling points of the focusing current under the deflection current (0,0); Δ is the unit step amount of the focusing current.

6. The method for collecting focusing current characteristic parameters of electron beam additive manufacturing equipment according to claim 4, characterized in that: The specific process of step 3 is as follows: Step 3.1, initialize the number of iterations k = 1; Step 3.2, start the coiling motor (8) of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment, the coiling motor (8) drives the receiving reel (6) to rotate, and drives the feeding reel (5) to rotate through the metal film (7), and the metal film (7) in the working section between the feeding horizontal axis (3) and the receiving horizontal axis (4) moves horizontally from the feeding side to the receiving side by a certain distance; Step 3.3, first start the electron beam additive manufacturing equipment focusing current characteristic parameter collection device; then set the focusing current of the electron beam additive manufacturing equipment to I f0 -kΔ, the electron beam additive manufacturing equipment is started, and at this time, the signal processing system of the focusing current characteristic parameter collection device of the electron beam additive manufacturing equipment starts timing; Step 3.4: The signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment collects the electrical signal sent by the beam receiving metal plate (9) of the receiving component in real time. When the electrical signal reaches a peak value and remains stable, the electron beam additive manufacturing equipment is turned off. At this time, the signal processing system of the device for collecting the characteristic parameters of the focusing current of the electron beam additive manufacturing equipment records the current value of the electron beam additive manufacturing equipment at the current focusing current I f0 -k×ΔThe breakdown time t from this start to this shutdown k ; Step 3.5: Set the number of iterations to k+1 and repeat steps 3.1-3.4 until k=K i , thus obtaining the focusing current I f0 -Δ,I f0 -2Δ,…,I f0 -K i K breakdown times corresponding to Δ Based on this, a fitting curve of focusing current and corresponding breakdown time is drawn. The focusing current corresponding to the valley value of the fitting curve is the current deflection current (I pxi ,I qyi ) under the optimal focusing current I fi ; In the above, i=,1,2,…,I, where I is the number of sampling points of the deflection current; K i is the deflection current (I pxi ,I qyi ) is the number of sampling points of the focusing current; Δ is the unit step size of the focusing current.

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