Additive manufacturing apparatus based on flexible forming chamber and powder spreading compensation control method

Abstract

The application discloses a kind of based on flexible forming cabin's additive manufacturing equipment and powder laying compensation control method, including steps: S1: the initial horizontal shift position of powder laying roller is collected with the initial rotation phase of powder laying roller, establishes the correlation model of the horizontal shift position of powder laying roller with the rotation phase of powder laying roller;S2: carry out slip error individual collection, obtain the first compensation adjustment amount corresponding to the horizontal shift position of powder laying roller;S3: according to the height of powder laying roller is corrected to first compensation adjustment amount;S4: carry out rotation error individual collection, obtain the second compensation adjustment amount corresponding to the rotation phase of powder laying roller;S5: according to the correlation model in step S1, first compensation adjustment amount and second compensation adjustment amount are mutually superimposed, obtain comprehensive compensation adjustment amount.The application can carry out compensation adjustment to powder laying quality.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and more specifically, to an additive manufacturing device based on a flexible molding chamber, and also to a powder spreading compensation control method for the additive manufacturing device based on a flexible molding chamber. Background Technology

[0002] In selective laser melting (SLM) of metals, the quality of powder spreading directly determines the density, mechanical properties, and dimensional accuracy of the parts. There are generally two methods of powder spreading: the first is the scraper-type method, where the powder surface is leveled using a scraper, but this method is prone to powder splattering; the second is the roller-type method, which provides a relatively smooth surface and is less prone to splattering.

[0003] When using a roller-type powder spreading method, the powder spreading roller needs to rotate during the powder sweeping process. Moreover, due to the eccentricity error of the powder spreading roller, periodic stripe defects will be generated on the powder spreading surface during the rotation of the powder spreading roller, which can easily cause quality defects on the powder spreading surface and affect the subsequent laser forming quality.

[0004] Therefore, a new technical solution is needed to address the surface quality problem of powder coating. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an additive manufacturing equipment based on a flexible molding chamber and a powder spreading compensation control method, which can compensate and adjust the thickness of powder spreading during the additive manufacturing process and improve the consistency of powder spreading thickness.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a powder spreading compensation control method, comprising the following steps:

[0007] S1: Collect the initial lateral position and initial rotation phase of the powder spreading roller, and establish a correlation model between the lateral position and rotation phase of the powder spreading roller.

[0008] S2: Collect the slippage error separately to obtain the first compensation adjustment amount corresponding to the powder spreading roller and the lateral position;

[0009] S3: Correct the height of the powder spreading roller according to the first compensation adjustment amount;

[0010] S4: Collect the rotational error separately to obtain the second compensation adjustment amount corresponding to the rotational phase of the powder spreading roller;

[0011] S5: Based on the correlation model in step S1, the first compensation adjustment amount and the second compensation adjustment amount are superimposed to obtain the comprehensive compensation adjustment amount.

[0012] Furthermore, the association model in step S1 is as follows:

[0013]

[0014] in, The rotation phase of the powder spreading roller. This represents the initial rotation phase of the powder spreading roller. This refers to the lateral movement position of the powder spreading roller. This represents the initial lateral movement position of the powder spreading roller. The angular velocity of the powder spreading roller. This refers to the lateral movement speed of the powder spreading roller.

[0015] Furthermore, the angular velocity of the powder spreading roller And the lateral movement speed of the powder spreading roller Adjust proportionally during the adjustment process.

[0016] Furthermore, in step S2, the process of separately collecting slippage error is as follows: keep the powder spreading roller non-rotating, the powder spreading roller completes one full powder spreading stroke along the powder spreading track, and collect the actual powder spreading height corresponding to each lateral movement position;

[0017] In step S2, a first error amount is obtained based on the difference between the actual powder spreading height and the standard powder spreading height, and the negative of the first error amount is used as the first compensation adjustment amount.

[0018] Furthermore, in step S4, the process of separately collecting rotational error is as follows: keep the powder spreading roller rotating, the powder spreading roller performs a complete powder spreading stroke along the powder spreading track, and collect the actual powder spreading height corresponding to each lateral movement position;

[0019] In step S4, a second error amount is obtained based on the difference between the actual powder spreading height and the standard powder spreading height;

[0020] Based on the correlation model in step S1, the lateral positions corresponding to the second error amount are converted into the rotation phase of the powder spreading roller to obtain the second compensation adjustment amount.

[0021] Further, in step S4, the lateral movement position of a complete powder spreading stroke is divided into several cycles, and the lateral movement of each cycle corresponds to a complete rotation of the powder spreading roller; the second error amount corresponding to each cycle is obtained, and the average value of the second error amount in each cycle is taken to obtain the final second compensation adjustment amount.

[0022] Furthermore, in step S4, the lateral movement position of a complete powder spreading stroke is divided into at least two cycles.

[0023] Furthermore, it also includes the following steps:

[0024] S6: The powder spreading roller rotates and is compensated and adjusted according to the comprehensive compensation adjustment amount; the slide moves along the powder spreading track for one complete powder spreading stroke, and the actual powder spreading height corresponding to each lateral position is collected to obtain the residual error corresponding to each lateral position.

[0025] S7: Compare the relationship between the residual error in step S6 and the threshold deviation. If the residual error corresponding to each horizontal movement position does not exceed the threshold deviation, the compensation is deemed qualified and the normal printing process begins.

[0026] The present invention also provides an additive manufacturing device based on a flexible molding chamber, including a molding chamber, a lifting platform, a powder spreading track, a slide, an adjuster, a mounting base, and a powder spreading roller. The top of the molding chamber is open, and the lifting platform is installed inside the molding chamber and can be adjusted up and down relative to the molding chamber. The powder spreading roller is located on the upper side of the molding chamber and is used to spread powder at the top opening of the molding chamber. During the powder spreading process, the powder spreading roller is controlled by the powder spreading compensation control method described above.

[0027] Furthermore, the slide is horizontally slidably mounted on the upper side of the forming chamber via a powder spreading track, and the mounting base is mounted on the slide and can be adjusted up and down relative to the slide via an adjuster; the powder spreading roller is rotatably mounted on the mounting base and can be driven to rotate by a rotary driver.

[0028] It also includes a displacement sensor, a distance sensor, and a phase sensor. The displacement sensor is used to detect the lateral position of the slide on the powder spreading track, the distance sensor is used to detect the actual powder spreading height on the powder spreading surface, and the phase sensor is used to detect the rotational phase position of the powder spreading roller.

[0029] In summary, the present invention has the following beneficial effects:

[0030] By separating the track slippage error and the eccentricity error of the powder spreading roller, the errors of the two can be collected independently, thereby improving the accuracy of subsequent compensation and facilitating subsequent comprehensive compensation adjustment.

[0031] By constructing a correlation model between the lateral position and rotation phase of the powder spreading roller, it is possible to determine the required track slip error compensation value and eccentricity error compensation value for each lateral position. The two compensation values ​​can be superimposed to form the final comprehensive compensation adjustment amount.

[0032] By comprehensively compensating and correcting the powder spreading roller, the surface forming quality problem of the powder spreading roller during the powder spreading process can be eliminated, the accuracy of compensation can be improved, and the final powder spreading precision can be improved. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an additive manufacturing equipment based on a flexible molding chamber according to this embodiment;

[0034] Figure 2 This is a schematic diagram of the eccentricity of the powder spreading roller in this embodiment.

[0035] Figure reference numerals: 1. Molding chamber; 2. Lifting platform; 3. Powder spreading track; 4. Slide seat; 5. Adjuster; 6. Mounting seat; 7. Powder spreading roller; 8. Laser component. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] This embodiment discloses an additive manufacturing equipment based on a flexible molding chamber, referring to... Figure 1 As shown, it includes a forming chamber 1, a lifting platform 2, a powder spreading track 3, a sliding seat 4, an adjuster 5, a mounting base 6, and a powder spreading roller 7. The forming chamber 1 has an open top structure. The lifting platform 2 is installed inside the forming chamber 1 and can be raised and lowered relative to the forming chamber 1, thereby realizing the flexible spatial adjustment of the forming chamber 1 to adapt to workpieces of different sizes.

[0038] Furthermore, the outer periphery of the lifting platform 2 is adapted to the inner periphery of the molding chamber 1, enabling smooth lifting and guiding. Moreover, a sliding sealing component is provided between the outer periphery of the lifting platform 2 and the inner wall of the molding chamber 1, thereby enabling a sliding seal on the space inside the molding chamber 1, ensuring that the upper side of the lifting platform 2 can effectively receive the metal powder to be 3D printed.

[0039] The powder spreading roller 7 is located on the upper side of the forming chamber 1 and spreads powder in a roller manner. During normal powder spreading, the powder spreading roller 7 moves laterally on the top of the forming chamber 1, which can scrape the metal powder on the top of the forming chamber 1 and ensure the stability of the subsequent laser component 8 when melting and solidifying the metal powder.

[0040] In this embodiment, the powder spreading track 3 is installed horizontally on the upper side of the forming chamber 1. The slide 4 is horizontally slidably installed on the upper side of the forming chamber 1 via the powder spreading track 3, and serves as the lateral movement base for the powder spreading roller 7.

[0041] The mounting base 6 is installed on the slide 4. Specifically, a vertically arranged guide rail can be used to install the mounting base 6 on the slide 4 in the vertical direction. In addition, an adjuster 5 is installed between the mounting base 6 and the slide 4. The adjuster 5 can drive the mounting base 6 to rise and fall, thereby adjusting the mounting base 6 and the powder spreading roller 7 installed on the mounting base 6 vertically.

[0042] The powder spreading roller 7 is rotatably mounted on the mounting base 6, and the rotation axis of the powder spreading roller 7 is horizontal. A rotary driver is installed on the mounting base 6, which drives the powder spreading roller 7 to rotate, so that the powder spreading roller 7 can rotate at a uniform speed during the powder spreading process, achieving a rolling spreading effect on the powder surface and effectively spreading the powder.

[0043] In addition, this embodiment also includes a displacement sensor, a distance sensor, and a phase sensor. The displacement sensor is installed between the powder spreading track 3 and the slide 4, and can specifically adopt a grating ruler-shaped structure to detect the lateral position of the slide 4 on the powder spreading track 3. Moreover, in this embodiment, the powder spreading track 3 is evenly divided into several detection points to obtain the relevant parameters of each detection point.

[0044] In this embodiment, the actual powder-spreading height on the powder-spreading surface can be detected by a distance sensor. Specifically, the distance sensor can be a laser rangefinder, which can detect the powder-spreading surface and thus characterize the thickness of the powder.

[0045] In this embodiment, a phase sensor can detect the rotational phase position of the powder spreading roller 7. Specifically, it can be installed outside the rotating shaft of the powder spreading roller 7 to accurately obtain the phase status of the powder spreading roller 7; and, by measuring the rate of change of the rotational phase of the powder spreading roller 7, the corresponding angular velocity can be obtained.

[0046] This embodiment also discloses a powder spreading compensation control method, which uses the additive manufacturing equipment described above to adjust the deviation of the powder spreading roller during the powder spreading process, thereby maintaining the surface height after powder spreading as flat and uniform.

[0047] During the powder spreading process, the spreading roller needs to move laterally and rotate, resulting in positional fluctuations that disrupt the surface condition of the spread powder. These fluctuations primarily originate from two sources: firstly, the vertical fluctuations that may occur as the spreading roller moves along the spreading track. Since the spreading track may have a slight deviation, this inevitably affects the height of the spreading roller. Secondly, the eccentricity of the spreading roller itself contributes to the problem. A slight deviation in the distance between the outer circumference of the spreading roller and its central axis of rotation creates an eccentricity error. During rotation, the contact position between the lower side of the spreading roller and the spreading surface changes, further affecting the height of the spread surface. For example, refer to... Figure 2 As shown, the powder spreading roller 7 has different outer diameters, R1 and R2, at two positions in the circumferential direction, resulting in a deviation in the circumferential dimension.

[0048] In this embodiment, the mounting base 6 can be adjusted up and down relative to the slide 4 by the adjuster 5, thereby adjusting the up and down position of the mounting base 6 and the powder spreading roller 7. After adjustment, the distance between the lower surface of the powder spreading roller 7 and the top of the forming chamber 1 will be slightly adjusted, thereby compensating for the powder spreading thickness.

[0049] Specifically, the powder-spreading compensation control method in this embodiment includes the following steps:

[0050] S1: Collect the initial lateral position and initial rotation phase of the powder spreading roller, and establish a correlation model between the lateral position and rotation phase of the powder spreading roller.

[0051] The powder spreading roller is divided into several detection points along the powder spreading track 3. These detection points are evenly distributed. The location number indicates the corresponding detection point, which determines the corresponding lateral movement position. and the corresponding rotation phase .

[0052] The specific association model is as follows:

[0053]

[0054] in, Indicates the position number. This represents the current rotation phase of the powder spreading roller. This represents the initial rotation phase of the powder spreading roller. This represents the current lateral position of the powder spreading roller. This represents the initial lateral movement position of the powder spreading roller. The angular velocity of the powder spreading roller. This refers to the lateral movement speed of the powder spreading roller.

[0055] In this embodiment, since the powder spreading roller simultaneously undergoes lateral movement and axial rotation, the correlation model can associate the lateral position with the rotation phase. When the powder spreading roller moves laterally and rotates at a constant speed, the correspondence between the two can be obtained. That is, when the powder spreading roller moves laterally to a certain position, the rotation phase of the powder spreading roller at that moment can be calculated using the correlation model.

[0056] Due to the influence of the correlation model, in this embodiment, the angular velocity of the powder spreading roller during normal operation is... And the lateral movement speed of the powder spreading roller Maintaining a proportional adjustment during the adjustment process allows the application of the aforementioned correlation model. When fluctuations occur during operation, the angular velocity of the powder-spreading roller... And the lateral movement speed of the powder spreading roller When the ratio changes, the association model is re-established.

[0057] S2: Collect slippage error separately to obtain the first compensation adjustment amount corresponding to the powder spreading roller and the lateral movement position. ;

[0058] Specifically, the process of separately collecting slippage error is as follows: Keeping the powder-spreading roller stationary, the roller will sweep the powder-spreading surface from the same position on the lower side. The roller will complete one full powder-spreading stroke (full powder-spreading stroke L) along the powder-spreading track, and the slippage position data will be collected. The corresponding actual powdering height ;

[0059] Based on the actual powdering height Standard powder spreading height The difference is used to calculate the first error amount. :

[0060]

[0061] Then take the first error amount The opposite of the first compensation adjustment amount .

[0062] S3: Perform initial track error correction. Specifically, according to the first compensation adjustment amount... The height of the powder spreading roller is corrected; that is, when the powder spreading roller moves with the powder spreading track to the corresponding position number i, the vertical position height of the powder spreading roller is adjusted by the adjuster, thereby correcting the first error. Make corrections.

[0063] S4: Collect the rotational error separately to obtain the second compensation adjustment amount corresponding to the rotational phase of the powder spreading roller;

[0064] Specifically, the process of separately collecting rotational error is as follows: keep the powder spreading roller rotating at a set angular velocity. During operation, the powder spreading roller completes one full powder spreading stroke (full powder spreading stroke L) along the powder spreading track, and the data at each lateral movement position are collected. Corresponding actual powdering height ;

[0065] Based on the actual powdering height Standard powder spreading height The difference yields the second error value. :

[0066]

[0067] Then, based on the correlation model in step S1, the second error quantity is... The corresponding horizontal shift positions Rotation phase converted to powder spreading roller Obtain the second compensation adjustment amount .

[0068] Specifically, since the powder spreading roller will rotate several revolutions during a complete powder spreading stroke, the same rotation phase will also occur. There are multiple sets of deviations.

[0069] Therefore, in step S4, a complete powder spreading stroke (complete powder spreading stroke L) is divided into p cycles. The lateral movement of each cycle corresponds to the complete rotation of the powder spreading roller. For example, the lateral movement position of a complete powder spreading stroke is divided into at least two cycles, or it can be divided into more cycles.

[0070] Within each period, let j represent the period number, and each position number corresponds to a second error quantity. Then, the second error amount within each period segment. Take the average value to obtain the final second compensation adjustment amount. :

[0071]

[0072] The final second compensation adjustment amount is obtained based on the comprehensive error situation in each period. .

[0073] S5: Based on the correlation model in step S1, adjust the first compensation amount. Second compensation adjustment amount The values ​​are superimposed to obtain the comprehensive compensation adjustment amount. ;

[0074]

[0075] in, This is a comprehensive compensation adjustment.

[0076] During subsequent normal powder spreading operation, the comprehensive compensation adjustment amount will be used. The powder spreading roller is compensated and adjusted, that is, when the slide moves along the powder spreading track, it moves to the corresponding lateral position. At this time, the regulator adjusts the height of the mounting base and the powder spreading roller, thereby compensating for the height error between the lower surface of the powder spreading roller and the powder surface, so that the surface height formed by the powder spreading roller sweeping the powder can be kept consistent, and thus the thickness of the powder spreading can be adjusted.

[0077] Furthermore, the powder-spreading compensation control method in this embodiment also includes step S6 compensation verification and step S7 closed-loop iteration, which can verify the state after the above comprehensive compensation adjustment and perform closed-loop iteration again to improve the accuracy during continuous operation.

[0078] Step S6: Compensation Verification.

[0079] The powder spreading roller rotates at a set angular velocity. During operation, the powder spreading roller completes one full powder spreading stroke (full powder spreading stroke L) along the powder spreading track, and the data at each lateral movement position are collected. Corresponding actual powdering height Obtain residual error ;

[0080]

[0081] Step S7: Closed-loop iteration.

[0082] Compare the residual error in step S6 Deviation from threshold The relationship between the horizontal shift positions The corresponding residual error All of them do not exceed the threshold deviation, that is: If the compensation is successful, it means that the toner application requirements have been met after comprehensive compensation and adjustment, and the normal printing process can begin.

[0083] Otherwise, perform the residual compensation step: repeat steps S2-S7 to iteratively update the first compensation adjustment. Second compensation adjustment amount Then repeat the calculation of residual error. Deviation from threshold The relationship continues until the compensation is deemed adequate.

[0084] If the residual compensation step is still deemed unqualified after three consecutive repetitions, then step S1 is repeated to readjust the powder spreading roller angular speed. And the lateral movement speed of the powder spreading roller And adjust the angular speed of the powder spreading roller. And the lateral movement speed of the powder spreading roller The ratio is used to rebuild the correlation model. Then, the compensation calculation is performed again using the new correlation model.

[0085] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling powder spreading compensation, characterized in that, Including the following steps: S1: Collect the initial lateral position and initial rotation phase of the powder spreading roller, and establish a correlation model between the lateral position and rotation phase of the powder spreading roller. S2: Collect the slippage error separately to obtain the first compensation adjustment amount corresponding to the powder spreading roller and the lateral position; S3: Correct the height of the powder spreading roller according to the first compensation adjustment amount; S4: Collect the rotational error separately to obtain the second compensation adjustment amount corresponding to the rotational phase of the powder spreading roller; S5: Based on the correlation model in step S1, the first compensation adjustment amount and the second compensation adjustment amount are superimposed to obtain the comprehensive compensation adjustment amount.

2. The powder spreading compensation control method according to claim 1, characterized in that, The association model in step S1 is: in, The rotation phase of the powder spreading roller. This represents the initial rotation phase of the powder spreading roller. This refers to the lateral movement position of the powder spreading roller. This represents the initial lateral movement position of the powder spreading roller. The angular velocity of the powder spreading roller. This refers to the lateral movement speed of the powder spreading roller.

3. The powder spreading compensation control method according to claim 2, characterized in that, The angular velocity of the powder spreading roller And the lateral movement speed of the powder spreading roller Adjust proportionally during the adjustment process.

4. The powder spreading compensation control method according to claim 1, characterized in that, In step S2, the process of separately collecting slippage error is as follows: keep the powder spreading roller non-rotating, and make the powder spreading roller complete one powder spreading stroke along the powder spreading track, and collect the actual powder spreading height corresponding to each lateral movement position; In step S2, a first error amount is obtained based on the difference between the actual powder spreading height and the standard powder spreading height, and the negative of the first error amount is used as the first compensation adjustment amount.

5. The powder spreading compensation control method according to claim 1, characterized in that, In step S4, the process of separately collecting rotational error is as follows: keep the powder spreading roller rotating, the powder spreading roller completes one full powder spreading stroke along the powder spreading track, and collect the actual powder spreading height corresponding to each lateral movement position; In step S4, a second error amount is obtained based on the difference between the actual powder spreading height and the standard powder spreading height; Based on the correlation model in step S1, the lateral positions corresponding to the second error amount are converted into the rotation phase of the powder spreading roller to obtain the second compensation adjustment amount.

6. The powder spreading compensation control method according to claim 5, characterized in that, In step S4, the lateral movement position of a complete powder spreading stroke is divided into several cycles, and the lateral movement of each cycle corresponds to a complete rotation of the powder spreading roller. The second error amount corresponding to each cycle is obtained, and the average value of the second error amount in each cycle is taken to obtain the final second compensation adjustment amount.

7. The powder spreading compensation control method according to claim 6, characterized in that, In step S4, the lateral movement position of a complete powder spreading stroke is divided into at least two cycles.

8. The powder spreading compensation control method according to claim 1, characterized in that, It also includes the following steps: S6: The powder spreading roller rotates and is compensated and adjusted according to the comprehensive compensation adjustment amount; the slide moves along the powder spreading track for one complete powder spreading stroke, and the actual powder spreading height corresponding to each lateral position is collected to obtain the residual error corresponding to each lateral position. S7: Compare the relationship between the residual error in step S6 and the threshold deviation. If the residual error corresponding to each horizontal movement position does not exceed the threshold deviation, the compensation is deemed qualified and the normal printing process begins.

9. An additive manufacturing device based on a flexible molding chamber, characterized in that, The device includes a forming chamber, a lifting platform, a powder spreading track, a slide, an adjuster, a mounting base, and a powder spreading roller. The top of the forming chamber is open, and the lifting platform is installed inside the forming chamber and can be adjusted up and down relative to the forming chamber. The powder spreading roller is located on the upper side of the forming chamber and is used to spread powder at the top opening of the forming chamber. During the powder spreading process, the powder spreading roller is controlled by the powder spreading compensation control method as described in any one of claims 1-8.

10. The additive manufacturing equipment based on a flexible molding chamber according to claim 9, characterized in that, The slide block is horizontally slidably mounted on the upper side of the forming chamber via a powder spreading track. The mounting base is mounted on the slide block and can be adjusted up and down relative to the slide block by an adjuster. The powder spreading roller is rotatably mounted on the mounting base and can be driven to rotate by a rotary driver. It also includes a displacement sensor, a distance sensor, and a phase sensor. The displacement sensor is used to detect the lateral position of the slide on the powder spreading track, the distance sensor is used to detect the actual powder spreading height on the powder spreading surface, and the phase sensor is used to detect the rotational phase position of the powder spreading roller.

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