CN116275116B - A dual-laser dual-galvanometer synchronous scanning method for powder bed additive manufacturing - Google Patents

Abstract

The invention discloses a method for synchronously scanning double laser and double vibrating mirrors, which is applied to powder bed additive manufacturing; the dual-laser scanning device mainly comprises a dual-laser same-point scanning mode, a dual-laser parallel scanning mode and a dual-laser following scanning mode. And when synchronous scanning is carried out, the current contour information is read, the generated path planning file is imported into different control cards, and a proper forming method is selected according to the printing requirement to finish sample forming. The invention greatly expands the application range of the multi-laser multi-vibrating mirror, improves the efficiency, simultaneously can avoid the influence of residual stress caused by regional scanning, and ensures the consistency of sample quality.

Description

A method for dual-laser dual-galvanometer synchronous scanning for powder bed additive manufacturing

Technical Field

The present invention relates to the field of metal additive manufacturing, and in particular to a method for dual-laser dual-galvanometer synchronous scanning for powder bed additive manufacturing.

Background technique

Compared with traditional manufacturing, additive manufacturing has the advantages of no need for props and molds, short development cycle, and the ability to form complex parts. In particular, powder bed additive manufacturing technology has the advantages of high precision and excellent mechanical properties of manufactured parts, and has developed rapidly in recent years. At present, the powders that are widely studied and used are mainly powders made of iron-based alloys, titanium alloys, aluminum alloys, nickel-based alloys, cobalt-based alloys, etc.

With the continuous advancement of technology, powder bed additive manufacturing has gradually developed in the direction of large size and high efficiency. The forming area is continuously expanded by increasing the number of lasers and galvanometers, and the efficiency is improved by dividing the samples into different areas and using multiple lasers to form them separately. However, this also creates a series of problems. For example, if different lasers are formed separately, the performance of different areas of the same part may be inconsistent; for example, the partition boundary is scanned by two laser beams, and unreasonable settings can easily lead to convex or concave boundaries, increased residual stress, and other problems. This reduces the quality of the parts and there are certain risks during use.

Summary of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings and deficiencies of the prior art and to provide a method for dual-laser dual-galvanometer synchronous scanning for powder bed additive manufacturing.

The present invention mainly adopts dual laser same-point scanning mode, dual laser parallel scanning mode and dual laser follow-up scanning mode. When performing synchronous scanning, the current contour information is read, the generated path planning file is imported into different control cards, and the appropriate forming method is selected according to the printing needs to complete the sample forming. The present invention greatly expands the scope of use of multi-laser multi-galvanometer, improves efficiency, and can avoid the residual stress caused by partition scanning, thereby ensuring the consistency of sample quality.

The present invention is achieved through the following technical solutions:

A method for dual-laser dual-galvanometer synchronous scanning for powder bed additive manufacturing, comprising the following steps:

S1: Read the current layer expansion information and generate a path planning file based on the selected scanning algorithm

S2: Import the file into different galvanometer control cards;

S3: make a judgment. If it is a synchronous scanning mode, the two laser beams jump to the printing starting point respectively; otherwise, perform partition scanning and jump to S5;

S4: When making a judgment, if it is the same-point scanning mode, jump to S5; if it is the parallel scanning mode, set the offset spacing; if it is the follow-up scanning mode, set the follow-up time difference or distance difference.

S5: Start printing.

In step S4, the same-point scanning mode includes the following sub-steps:

S4-1: Import the path planning file into the galvanometer control card;

S4-2: The double beam jumps to the starting point of the printing scan line;

S4-3: Start printing if the starting point positions are the same, otherwise wait;

S4-4: When a scan line ends, if the distance between the starting point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, steps S3-2 and S3-3 are executed;

S4-5: Loop step S4-4 until printing is completed.

In step S4, the parallel scanning mode includes the following sub-steps:

S4-11: Import the path planning file into the galvanometer control card;

S4-22: Read the parallel spacing parameter perpendicular to the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data;

S4-33: The double beam jumps to the starting point of the printing scan line;

S4-44: Start printing if the starting point position meets the parallel offset spacing, otherwise wait;

S4-55: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, step S4-33 and step S4-44 are executed;

S4-66: Loop step S4-55 until printing is completed.

In step S4, the following scanning mode includes the following sub-steps:

S4-111: Import the path planning file into the galvanometer control card;

S4-222: Read the following spacing parameter in the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data;

S4-333: The double beam jumps to the starting point of the printing scan line;

S4-444: Start printing if the starting point position meets the following offset spacing, otherwise wait;

S4-555: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then print directly, otherwise execute step S4-333 and step S4-444;

S4-666: Loop step S4-555 until printing is completed.

The wavelengths of the dual lasers are the same or different.

In step S2, in the synchronous scanning mode, the same path planning file is imported into different galvanometer control cards.

In step S3, when the dual lasers jump to the printing starting point, position detection is required. If the starting positions of the two are different, it is necessary to wait until the positions of the two are the same.

In step S4, if it is a same-point scanning mode and the wavelength of the laser is the same, the laser power should be reduced or the scanning speed should be increased to achieve the same energy input as the original single laser; if the wavelength of the laser is different, a composite light spot can be formed.

In step S4, when the laser jumps, if the next position distance of the jump is one scanning pitch, there is no need to perform position detection; otherwise, position detection is required again to ensure that the printing starting point position is the same to prevent the galvanometer from jumping at different distances and causing asynchrony.

In step S4, the parallel scanning mode is to preset an offset distance perpendicular to the scanning direction (the minimum offset distance is about half of the laser spot diameter, and the maximum offset distance is about the laser spot diameter), that is, the offset distance is not less than half of the laser spot diameter and not greater than the laser spot diameter, otherwise the melting path will be discontinuous.

Compared with the prior art, the present invention has the following advantages and effects:

The present invention adds a synchronous scanning algorithm and expands the application scope of the dual laser dual galvanometer.

The present invention adopts same-point scanning to expand process parameters, thereby increasing the process window; and can couple lasers with different wavelengths.

The present invention adopts parallel scanning to greatly improve the scanning efficiency and ensure the consistency of the performance of large parts.

The present invention adopts follow-up scanning to achieve the purpose of front preheating and rear heat preservation, thereby improving the forming quality of parts.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the operation flow of the present invention.

FIG. 2 is a block diagram of synchronous scanning classification according to the present invention.

In the figure: 1 is galvanometer 1; 2 is the laser beam in the same-point scanning mode; 3 is the laser beam in the follow-up scanning mode; 4 is the laser beam in the parallel scanning mode; 5 is the forming plane; 6 is galvanometer 2; 7 is the laser beam in the parallel scanning mode; 8 is the laser beam in the follow-up scanning mode, and 9 is the laser beam in the same-point scanning mode.

Detailed ways

The present invention is further described in detail below in conjunction with specific embodiments.

Example

As shown in Figure 1-2. The present invention discloses a method for dual-laser dual-galvanometer synchronous scanning applied to powder bed additive manufacturing, comprising the following steps:

A method for dual-laser dual-galvanometer synchronous scanning applied to powder bed additive manufacturing, comprising the following steps:

S1: Read the current layer expansion information and generate a path planning file based on the selected scanning algorithm

S2: Import the file into different galvanometer control cards;

S3: make a judgment. If it is a synchronous scanning mode, the two laser beams jump to the printing starting point respectively; otherwise, perform partition scanning and jump to S5;

S4: When making a judgment, if it is the same-point scanning mode, jump to S5; if it is the parallel scanning mode, set the offset spacing; if it is the follow-up scanning mode, set the follow-up time difference or distance difference.

S5: Start printing.

In step S4, the same-point scanning mode includes the following sub-steps:

S4-1: Import the path planning file into the galvanometer control card;

S4-2: The double beam jumps to the starting point of the printing scan line;

S4-3: Start printing if the starting point positions are the same, otherwise wait;

S4-4: When a scan line ends, if the distance between the starting point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, steps S3-2 and S3-3 are executed;

S4-5: Loop step S4-4 until printing is completed.

In step S4, the parallel scanning mode includes the following sub-steps:

S4-11: Import the path planning file into the galvanometer control card;

S4-22: Read the parallel spacing parameter perpendicular to the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data;

S4-33: The double beam jumps to the starting point of the printing scan line;

S4-44: Start printing if the starting point position meets the parallel offset spacing, otherwise wait;

S4-55: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, step S4-33 and step S4-44 are executed;

S4-66: Loop step S4-55 until printing is completed.

In step S4, the following scanning mode includes the following sub-steps:

S4-111: Import the path planning file into the galvanometer control card;

S4-222: Read the following spacing parameter in the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data;

S4-333: The double beam jumps to the starting point of the printing scan line;

S4-444: Start printing if the starting point position meets the following offset spacing, otherwise wait;

S4-555: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then print directly, otherwise execute step S4-333 and step S4-444;

S4-666: Loop step S4-555 until printing is completed.

The wavelengths of the dual lasers are the same or different.

In step S2, in the synchronous scanning mode, the same path planning file is imported into different galvanometer control cards.

In step S3, when the dual lasers jump to the printing starting point, position detection is required. If the starting positions of the two are different, it is necessary to wait until the positions of the two are the same. The waiting time generally does not exceed 0.1s.

In step S4, if it is the same point scanning mode and the wavelength of the laser is the same, the laser power should be reduced or the scanning speed should be increased to achieve the same energy input as the original single laser; if the wavelength of the laser is different, a composite light spot can be formed. The composite light spot can be used for in-situ heat preservation, preheating and remelting, etc., and can also be used for the processing of some materials with high reflectivity of infrared laser.

In step S4, when the laser jumps, if the next position distance of the jump is one scanning pitch, there is no need to perform position detection; otherwise, position detection is required again to ensure that the printing starting point position is the same to prevent the galvanometer from jumping at different distances and causing asynchrony.

In step S4, the parallel scanning mode is to preset an offset distance perpendicular to the scanning direction (the minimum offset distance is about half of the laser spot diameter, and the maximum offset distance is about the laser spot diameter), that is, the offset distance is not less than half of the laser spot diameter, and not greater than the laser spot diameter, otherwise the melting path will be discontinuous. By adjusting the parallel scanning spacing, the efficiency of the partition scanning can be achieved or even exceeded, and the problem of residual stress in the overlap area of the partition scanning can be solved.

The follow-up scanning mode is that the two laser beams have a certain offset distance in the scanning direction. The time difference can be set to ensure that the two are in a front-and-back state, or the distance difference can be used to ensure the front-and-back state. The time difference and distance difference can be positive or negative, indicating the relative position of different lasers.

As described above, the present invention can be better implemented.

The implementation methods of the present invention are not limited to the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims (1)

1. A method for dual-laser dual-galvanometer synchronous scanning for powder bed additive manufacturing, characterized by comprising the following steps: S1: Read the current layer expansion information and form a path planning file according to the selected scanning algorithm; S2: Import the path planning file into different galvanometer control cards; S3: make a judgment. If it is a synchronous scanning mode, the two laser beams jump to the printing starting point respectively; otherwise, perform partition scanning and jump to S5; S4: When making a judgment, if it is the same-point scanning mode, jump to S5; if it is the parallel scanning mode, set the offset spacing; if it is the follow-up scanning mode, set the follow-up time difference or distance difference; S5: Start printing; In step S4, the same-point scanning mode includes the following sub-steps: S4-1: Import the path planning file into the galvanometer control card; S4-2: The double beam jumps to the starting point of the printing scan line; S4-3: Start printing if the starting point positions are the same, otherwise wait; S4-4: When a scan line ends, if the distance between the starting point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, steps S4-2 and S4-3 are executed; S4-5: loop step S4-4 until printing is completed; In step S4, the parallel scanning mode includes the following sub-steps: S4-11: Import the path planning file into the galvanometer control card; S4-22: Read the parallel spacing parameter perpendicular to the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data; S4-33: The double beam jumps to the starting point of the printing scan line; S4-44: Start printing if the starting point position meets the parallel offset spacing, otherwise wait; S4-55: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then printing is performed directly, otherwise, step S4-33 and step S4-44 are executed; S4-66: loop step S4-55 until printing is completed; In step S4, the following scanning mode includes the following sub-steps: S4-111: Import the path planning file into the galvanometer control card; S4-222: Read the following spacing parameter in the scanning direction set by the software, and determine whether it meets the requirements. If not, prompt the user to modify the data; S4-333: The double beam jumps to the starting point of the printing scan line; S4-444: Start printing if the starting point position meets the following offset spacing, otherwise wait; S4-555: When a scan line ends, if the distance between the start point of the next scan line and the end point of the current scan line is a scan pitch length, then print directly, otherwise execute step S4-333 and step S4-444; S4-666: loop step S4-555 until printing is completed; The wavelengths of the dual lasers are the same or different; In step S2, in the synchronous scanning mode, the same path planning file is imported into different galvanometer control cards; In step S3, when the dual lasers jump to the printing starting point, position detection is required. If the starting positions of the two lasers are different, it is necessary to wait until the positions of the two lasers are the same. In step S4, if it is a same-point scanning mode, when the wavelengths of the lasers are the same, the laser power should be reduced or the scanning speed should be increased to achieve the same energy input as the original single laser; if the wavelengths of the lasers are different, a composite light spot is formed; In step S4, when the laser jumps, if the next position distance of the jump is one scanning pitch, there is no need to perform position detection; otherwise, position detection needs to be performed again to ensure that the printing starting point position is the same to prevent the galvanometer from jumping at different distances and causing asynchronism; In step S4, the parallel scanning mode is to preset an offset distance perpendicular to the scanning direction, that is, the offset distance is not less than half of the diameter of the laser spot and not greater than the diameter of the laser spot, otherwise the melting path will be discontinuous.