Laser control signal transmission device for additive equipment

Abstract

The utility model belongs to the technical field of additive manufacturing equipment, and relates to a laser control signal transmission device for additive manufacturing equipment, which comprises a control card, a laser and a signal transmission cable. The control card has a first interface; the laser has a second interface; a signal transmission cable is connected with the first interface and the second interface, one end, connected with the first interface, of the signal transmission cable is provided with a modulation circuit, and one end, connected with the second interface, of the signal transmission cable is provided with a demodulation circuit; according to the utility model, a transmission mode of differential signals is introduced, the differential signals have strong anti-interference capability, and the capability of resisting electromagnetic environment interference of laser switching signals and laser power signals is improved, so that accurate control and stable work of the laser are ensured, the phenomena of disordered forming rhythm, overburning, underburning and the like of parts in the additive manufacturing process are avoided, and the production efficiency is improved. And the quality of parts is improved.

Description

Technical Field

[0001] This utility model relates to the field of additive manufacturing equipment technology, specifically to a laser control signal transmission device for additive manufacturing equipment. Background Technology

[0002] In the field of additive manufacturing, lasers are core components, and their precise control is crucial for achieving high-quality, high-precision component manufacturing. Metal additive manufacturing equipment constructs three-dimensional objects by layering metal powder or wire. In this process, the switching and power adjustment of the laser directly determine the accuracy and stability of physical processes such as melting and solidification.

[0003] Laser control signals in metal additive manufacturing equipment mainly fall into two categories: laser switch signals and laser power signals. Laser switch signals are typically designed as single-ended signals, used to control the laser's on / off state; they are simple, direct, and easy to implement. Laser power signals are used to adjust the laser's output power to achieve precise control of the melting process. Because laser power adjustment requires high precision and stability, laser power signals are often transmitted in analog form.

[0004] There is some research on metal additive manufacturing equipment in the prior art. See patent document with application number 201420013022.7, which discloses a laser additive manufacturing equipment for metal parts, including a galvanometer laser melting and forming device and a thin-walled wall preparation device. The galvanometer laser melting and forming device is similar to a selective laser melting and forming device without a forming cylinder. The thin-walled wall preparation device is installed in the atmosphere cavity of the selective laser melting and forming device and is used to complete the manufacturing of thin-walled walls layer by layer to form a conformal cavity. The laser melting and forming device is used to complete the laying of metal powder in the conformal cavity and the selective laser melting and forming of the metal powder.

[0005] Therefore, by combining a galvanometer laser melting and forming device with a thin-walled preparation device, efficient and precise manufacturing of metal parts within a conformal cavity can be achieved. However, the electromagnetic environment inside additive manufacturing equipment is often very complex during operation. In this complex electromagnetic environment, laser switching signals and laser power signals are easily interfered with, leading to erroneous laser emission or incorrect output power. This, in turn, can cause phenomena such as disordered part forming rhythm, overheating, and underheating during additive manufacturing, affecting the quality of the parts. Utility Model Content

[0006] To address the technical problem in the background art that laser switch signals and laser power signals are easily interfered with in the complex electromagnetic environment inside additive manufacturing equipment, leading to erroneous laser emission or incorrect output power, this utility model provides a laser control signal transmission device for additive manufacturing equipment.

[0007] This invention relates to a laser control signal transmission device for additive manufacturing equipment. Before being transmitted to the laser, the first single-ended signal (i.e., the laser switch signal) and the first single-ended analog signal (i.e., the laser power signal) output by the control card sequentially pass through a modulation circuit, a signal transmission cable, and a demodulation circuit. During signal transmission, the modulation circuit converts the first single-ended signal into a first differential signal and the first single-ended analog signal into a second differential signal, allowing the laser switch signal and laser power signal to be transmitted in differential signal form through the signal transmission cable. By introducing a differential signal transmission method, this invention enhances the anti-interference capability of the differential signal, improving the ability of the laser switch signal and laser power signal to resist electromagnetic interference. This ensures precise control and stable operation of the laser, preventing phenomena such as chaotic part forming rhythm, overheating, and underheating during additive manufacturing, thus improving part quality.

[0008] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0009] A laser control signal transmission device for additive manufacturing equipment includes a control card, a laser, and a signal transmission cable. The control card has a first interface, and a power supply is provided in the first interface. The power supply generates a first single-ended signal and a first single-ended analog signal. The laser has a second interface. The signal transmission cable connects the first interface and the second interface, and a modulation circuit is provided at one end of the signal transmission cable connected to the first interface, and a demodulation circuit is provided at the other end connected to the second interface. The modulation circuit converts the first single-ended signal and the first single-ended analog signal into a first differential signal and a second differential signal, respectively. The demodulation circuit converts the first differential signal and the second differential signal into a second single-ended signal and a second single-ended analog signal, respectively. The laser receives the second single-ended signal and the second single-ended analog signal through the second interface and performs material forming based on the second single-ended signal and the second single-ended analog signal.

[0010] In one specific implementation, the second single-ended signal is a first single-ended signal recovered from the first differential signal, and the second single-ended analog signal is a first single-ended analog signal recovered from the second differential signal.

[0011] In one specific implementation scheme, the modulation circuit includes a first modulation unit and a second modulation unit; the first modulation unit is connected to a first interface and a signal transmission cable, and is used to convert a first single-ended signal into a first differential signal; the second modulation unit is connected to the first interface and the signal transmission cable, and is used to convert the first single-ended analog signal into a second differential signal after pulse width modulation.

[0012] In one specific implementation, the first modulation unit is a first RS485 driver, which is connected to the first interface and the signal transmission cable; the second modulation unit includes a triangular wave generator, a comparator, and a second RS485 driver; the triangular wave generator, the comparator, and the second RS485 driver are sequentially distributed along the signal transmission direction between the first interface and the signal transmission cable; wherein, the triangular wave generator is used to generate a periodic triangular wave signal, the comparator is used to compare a first single-ended analog signal with the triangular wave signal and generate a pulse width modulation signal, and the second RS485 driver is used to convert the pulse width modulation signal into a second differential signal.

[0013] In one specific implementation, the frequency of the triangular wave generator is greater than or equal to 10MHz.

[0014] In one specific implementation scheme, the demodulation circuit includes a first demodulation unit and a second demodulation unit; the first demodulation unit is connected to a signal transmission cable and a second interface, and is used to convert a first differential signal into a second single-ended signal; the second demodulation unit is connected to a signal transmission cable and a second interface, and is used to convert the second differential signal into a second single-ended analog signal.

[0015] In one specific implementation, the first demodulation unit is a first RS485 receiver, which is connected to the signal transmission cable and the second interface; the second demodulation unit includes a second RS485 receiver and a filter; the second RS485 receiver and the filter are distributed sequentially along the signal transmission direction between the signal transmission cable and the second interface.

[0016] In one specific implementation, the cutoff frequency of the filter is 1 / 10 of the frequency of the triangular wave generator.

[0017] In one specific implementation scheme, both ends of the signal transmission cable are connected to plugs; the modulation circuit is built into the plug at the end of the signal transmission cable connected to the first interface, and the demodulation circuit is built into the plug at the end of the signal transmission cable connected to the second interface.

[0018] In one specific implementation, the response time of the second modulation unit is less than or equal to 50 μs, and the signal processing delay of the second demodulation unit is less than or equal to 1 μs.

[0019] In summary, this utility model has the following beneficial technical effects:

[0020] 1. This utility model relates to a laser control signal transmission device for additive manufacturing equipment. Before being transmitted to the laser, the first single-ended signal (i.e., laser switch signal) and the first single-ended analog signal (i.e., laser power signal) output by the control card pass sequentially through a modulation circuit, a signal transmission cable, and a demodulation circuit. During signal transmission, the modulation circuit converts the first single-ended signal into a first differential signal and the first single-ended analog signal into a second differential signal, allowing the laser switch signal and laser power signal to be transmitted in differential signal form through the signal transmission cable. This utility model, by introducing a differential signal transmission method, provides strong anti-interference capabilities, improving the ability of the laser switch signal and laser power signal to resist electromagnetic interference. This ensures precise control and stable operation of the laser, avoiding phenomena such as chaotic part forming rhythm, overheating, and underheating during additive manufacturing, thus improving part quality.

[0021] 2. The laser control signal transmission device for additive manufacturing equipment of this utility model has a second modulation unit that uses pulse width modulation technology to convert the first single-ended analog signal into a second differential signal, thereby improving the stability of signal transmission and ensuring the accuracy of laser power control, thus improving the quality of the parts.

[0022] 3. The laser control signal transmission device for additive manufacturing equipment of this utility model has a response time of less than or equal to 50μs for the second modulation unit and a signal processing delay of less than or equal to 1μs for the second demodulation unit, which ensures the speed and accuracy of signal processing, thereby achieving high-quality printing. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of existing technology, intended to illustrate laser switching signals and laser power signals.

[0024] Figure 2 This is a schematic diagram of the existing technology.

[0025] Figure 3 This is a schematic diagram of the overall structure of the laser control signal transmission device for additive manufacturing equipment according to this utility model.

[0026] Figure 4 This is a partial structural schematic diagram of the laser control signal transmission device for additive manufacturing equipment, intended to illustrate the modulation circuit.

[0027] Figure 5 This is a partial structural schematic diagram of the laser control signal transmission device for additive manufacturing equipment, intended to illustrate the demodulation circuit.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Laser switch signal; 2. Laser power signal; 3. Signal transmission cable; 31. First interface; 32. Second interface; 4. Modulation circuit; 41. First RS485 driver; 42. Triangle wave generator; 43. Comparator; 44. Second RS485 driver; 5. Demodulation circuit; 51. First RS485 receiver; 52. Second RS485 receiver; 53. Filter. Detailed Implementation

[0030] The technical solution of this utility model will be further explained and described below with reference to the accompanying drawings and embodiments, but this utility model is not limited to the embodiments described below.

[0031] Reference Figure 1 and Figure 2 In the field of additive manufacturing, additive manufacturing equipment contains a large number of electronic components and electrical systems, such as power modules, control systems, and sensors. These components and systems generate various electromagnetic fields and waves during operation, which intertwine to form a complex electromagnetic environment. Currently, the control card directly transmits the laser switch signal 1 and laser power signal 2 via signal transmission cable 3. However, during transmission, the laser switch signal 1 and laser power signal 2 are easily interfered with by the electromagnetic environment, causing the laser to emit light incorrectly or output incorrect power. This can lead to problems such as disordered part forming rhythm, overheating, and underheating during additive manufacturing, affecting part quality. This invention aims to provide a laser control signal transmission device for additive manufacturing equipment, improving the ability of the laser switch signal 1 and laser power signal 2 to resist electromagnetic interference, thereby ensuring precise control and stable operation of the laser.

[0032] Example 1:

[0033] Reference Figure 3 and Figure 4A laser control signal transmission device for additive manufacturing equipment includes: a control card, a laser, and a signal transmission cable. The control card has a first interface 31, within which a power supply is installed. The power supply generates a first single-ended signal and a first single-ended analog signal. The laser has a second interface 32. The signal transmission cable connects the first interface 31 and the second interface 32, with a modulation circuit at one end connected to the first interface 31 and a demodulation circuit at the other end connected to the second interface 32. The power supply generates the first single-ended signal and the first single-ended analog signal. The modulation circuit 4 converts the first single-ended signal and the first single-ended analog signal into a first differential signal and a second differential signal, respectively. Both the first differential signal and the second differential signal are transmitted to the demodulation circuit via the signal transmission cable 3. The demodulation circuit converts the first differential signal and the second differential signal into a second single-ended signal and a second single-ended analog signal, respectively. The laser receives the second single-ended signal and the second single-ended analog signal through the second interface 32 and performs material forming based on the second single-ended signal and the second single-ended analog signal.

[0034] The second single-ended signal is the first single-ended signal reconstructed from the first differential signal, and the second single-ended analog signal is the first single-ended analog signal reconstructed from the second differential signal.

[0035] Specifically, the first single-ended signal output by the control card is laser switch signal 1, used to control the laser's on and off states; the first single-ended analog signal output by the control card is laser power signal 2, used to control the laser's output power. The voltage range of laser power signal 2 is between 0V and 10V, corresponding to an adjustable laser power from 0W to its maximum value.

[0036] Specifically, the first interface 31 is a DB15 interface to ensure a stable connection between the signal transmission cable 3 and the laser.

[0037] Reference Figure 3 and Figure 4 The modulation circuit 4 includes a first modulation unit and a second modulation unit. The first modulation unit is connected to the first interface 31 and the signal transmission cable 3, and is used to convert the first single-ended signal into a first differential signal; the second modulation unit is connected to the first interface 31 and the signal transmission cable 3, and is used to convert the first single-ended analog signal into a second differential signal after pulse width modulation.

[0038] Specifically, the first modulation unit is the first RS485 driver 41, which is connected to the first interface 31 and the signal transmission cable 3.

[0039] Specifically, the second modulation unit includes a triangular wave generator 42, a comparator 43, and a second RS485 driver 44; the triangular wave generator 42, the comparator 43, and the second RS485 driver 44 are sequentially distributed along the signal transmission direction between the first interface 31 and the signal transmission cable 3; wherein, the triangular wave generator 42 is used to generate a periodic triangular wave signal, the comparator 43 is used to compare the first single-ended analog signal with the triangular wave signal and generate a pulse width modulation signal, and the second RS485 driver 44 is used to convert the pulse width modulation signal into a second differential signal.

[0040] More specifically, the frequency of the triangular wave signal generated by the triangular wave generator 42 is greater than or equal to 10MHz to ensure the rapid response and precise control of the laser power signal 2.

[0041] Reference Figure 3 and Figure 5 The demodulation circuit 5 includes a first demodulation unit and a second demodulation unit. The first demodulation unit is connected to the signal transmission cable 3 and the second interface 32, and is used to convert the first differential signal into a second single-ended signal; the second demodulation unit is connected to the signal transmission cable 3 and the second interface 32, and is used to convert the second differential signal into a second single-ended analog signal.

[0042] Specifically, the first demodulation unit is the first RS485 receiver 51, which is connected to the signal transmission cable 3 and the second interface 32. The first RS485 receiver 51 uses differential-to-single-ended technology to convert the first differential signal into a second single-ended signal.

[0043] Specifically, the second demodulation unit includes a second RS485 receiver 52 and a filter 53; the second RS485 receiver 52 and the filter 53 are sequentially distributed along the signal transmission direction between the signal transmission cable 3 and the second interface 32. The filter 53 is used to filter the second single-ended analog signal to remove high-frequency noise from the second single-ended analog signal.

[0044] More specifically, filter 53 can be configured as an RC active filter, a low-pass filter, a band-pass filter, etc., the specific choice depending on the signal characteristics and noise conditions. Preferably, filter 53 is configured as an RC active filter to provide stable filtering effect and low signal loss.

[0045] More specifically, the cutoff frequency of filter 53 is 1 / 10 of the frequency of triangular wave generator 42. While ensuring the stability of laser control signal transmission, it reduces the delay of laser control signal to 1μs, thereby improving the overall performance of the device.

[0046] Example 2:

[0047] Reference Figure 3In this embodiment, the laser control signal transmission device for the additive manufacturing equipment is based on embodiment 1, with plugs connected to both ends of the signal transmission cable 3. The modulation circuit 4 is built into the plug at the end of the signal transmission cable 3 that connects to the first interface 31, and the demodulation circuit 5 is built into the plug at the end of the signal transmission cable 3 that connects to the second interface 32.

[0048] In this embodiment, the modulation circuit 4 and the demodulation circuit 5 are respectively placed in the plugs at both ends of the signal transmission cable 3, which facilitates installation, maintenance and replacement.

[0049] Example 3:

[0050] In this embodiment, the laser control signal transmission device for additive manufacturing equipment, based on embodiment 1, has a response time of less than or equal to 50 μs for the second modulation unit and a signal processing delay of less than or equal to 1 μs for the second demodulation unit, ensuring rapid response and accurate transmission of the laser control signal, thereby ensuring high-precision printing of the metal additive manufacturing equipment.

[0051] The working principle of the laser control signal transmission device for additive manufacturing equipment of this utility model is as follows: First, the first interface 31 and the second interface 32 are connected through the signal transmission cable 3 to realize the connection between the control card and the laser; when the additive manufacturing equipment is started, the power supply generates a first single-ended signal and a first single-ended analog signal; then, the first RS485 driver 41 converts the first single-ended signal into a first differential signal, the triangular wave generator 42 generates a periodic triangular wave signal, the comparator 43 compares the first single-ended analog signal with the triangular wave signal generated by the triangular wave generator 42 and generates a pulse width modulation signal, and the second RS485 driver 44 converts the pulse width modulation signal generated by the comparator 43 into a pulse width modulation signal. The first differential signal is converted into a second differential signal; subsequently, the first differential signal is transmitted to the first RS485 receiver 51 through the signal transmission cable 3, and the second differential signal is transmitted to the second RS485 receiver 52 through the signal transmission cable 3; the first RS485 receiver 51 converts the first differential signal into a second single-ended signal, and the second RS485 receiver 52 and the filter 53 convert the second differential signal into a second single-ended analog signal; finally, the laser receives the second single-ended signal and the second single-ended analog signal through the second interface 32, and performs material forming based on the second single-ended signal and the second single-ended analog signal, thereby realizing precise control of the laser switch signal 1 and the laser power signal 2.

[0052] The preferred embodiments of this utility model are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A laser control signal transmission device for additive manufacturing equipment, characterized in that, include: The control card has a first interface (31), and a power supply is provided in the first interface (31), the power supply generating a first single-ended signal and a first single-ended analog signal; A laser having a second interface (32); And a signal transmission cable (3) is provided to connect the first interface (31) and the second interface (32), and the end of the signal transmission cable (3) connected to the first interface (31) is provided with a modulation circuit (4), and the end connected to the second interface (32) is provided with a demodulation circuit (5); The modulation circuit (4) converts the first single-ended signal and the first single-ended analog signal into a first differential signal and a second differential signal, respectively. The demodulation circuit (5) converts the first differential signal and the second differential signal into a second single-ended signal and a second single-ended analog signal, respectively. The laser receives the second single-ended signal and the second single-ended analog signal through the second interface (32) and performs material forming based on the second single-ended signal and the second single-ended analog signal.

2. The laser control signal transmission device for additive manufacturing equipment according to claim 1, characterized in that: The second single-ended signal is the first single-ended signal recovered from the first differential signal, and the second single-ended analog signal is the first single-ended analog signal recovered from the second differential signal.

3. The laser control signal transmission device for additive manufacturing equipment according to claim 2, characterized in that: The modulation circuit (4) includes a first modulation unit and a second modulation unit; The first modulation unit is connected to the first interface (31) and the signal transmission cable (3) to convert the first single-ended signal into a first differential signal; The second modulation unit connects the first interface (31) and the signal transmission cable (3) to convert the first single-ended analog signal into a second differential signal after pulse width modulation.

4. The laser control signal transmission device for additive manufacturing equipment according to claim 3, characterized in that: The first modulation unit is a first RS485 driver (41), which is connected to the first interface (31) and the signal transmission cable (3). The second modulation unit includes a triangular wave generator (42), a comparator (43), and a second RS485 driver (44); The triangular wave generator (42), comparator (43) and second RS485 driver (44) are distributed sequentially along the signal transmission direction between the first interface (31) and the signal transmission cable (3); The triangular wave generator (42) is used to generate a periodic triangular wave signal, the comparator (43) is used to compare the first single-ended analog signal with the triangular wave signal and generate a pulse width modulation signal, and the second RS485 driver (44) is used to convert the pulse width modulation signal into a second differential signal.

5. The laser control signal transmission device for additive manufacturing equipment according to claim 4, characterized in that: The frequency of the triangular wave generator (42) is greater than or equal to 10MHz.

6. The laser control signal transmission device for additive manufacturing equipment according to claim 4, characterized in that: The demodulation circuit (5) includes a first demodulation unit and a second demodulation unit; The first demodulation unit connects the signal transmission cable (3) and the second interface (32) to convert the first differential signal into a second single-ended signal; The second demodulation unit connects the signal transmission cable (3) and the second interface (32) to convert the second differential signal into a second single-ended analog signal.

7. The laser control signal transmission device for additive manufacturing equipment according to claim 6, characterized in that: The first demodulation unit is a first RS485 receiver (51), which is connected to the signal transmission cable (3) and the second interface (32). The second demodulation unit includes a second RS485 receiver (52) and a filter (53); The second RS485 receiver (52) and filter (53) are sequentially distributed between the signal transmission cable (3) and the second interface (32) along the signal transmission direction.

8. The laser control signal transmission device for additive manufacturing equipment according to claim 7, characterized in that: The cutoff frequency of the filter (53) is 1 / 10 of the frequency of the triangular wave generator (42).

9. The laser control signal transmission device for additive manufacturing equipment according to claim 8, characterized in that: The signal transmission cable (3) has plugs connected to both ends; The modulation circuit (4) is built into the plug at one end of the signal transmission cable (3) that connects to the first interface (31), and the demodulation circuit (5) is built into the plug at one end of the signal transmission cable (3) that connects to the second interface (32).

10. The laser control signal transmission device for additive manufacturing equipment according to any one of claims 6-9, characterized in that: The response time of the second modulation unit is less than or equal to 50 μs, and the signal processing delay of the second demodulation unit is less than or equal to 1 μs.

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