Optical calibration tooling, 3D printing equipment, and 3D printing optical calibration method

Abstract

The present invention provides an optical calibration tool, a 3D printing device and a 3D printing optical calibration method, wherein the optical calibration tool comprises: an illumination unit; a calibration plate, wherein the calibration plate comprises a calibration plate substrate and calibration points, wherein the calibration plate substrate has a first surface and a second surface opposite to each other, wherein the calibration points are arranged on the first surface of the calibration plate substrate, and the second surface of the calibration plate substrate faces the illumination unit; and a coating, wherein the coating covers the first surface of the calibration plate substrate, and the surface roughness of the coating is higher than the surface roughness of the calibration plate substrate. The coating solves the reflection and refraction problems of the calibration plate, and the illumination unit makes the calibration points of the calibration plate imaged on the coating, so that the image captured by the camera is clear and the calibration effect obtained is accurate, thereby improving the printing accuracy of the 3D printing device.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to an optical calibration tool, a 3D printing device and a 3D printing optical calibration method. Background Art

[0002] 3D printing is a type of rapid prototyping technology. It is a technology that uses digital model files as the basis and uses powdered metal, plastic, resin and other bondable materials to construct objects by printing layer by layer. 3D printing equipment manufactures 3D objects by executing this printing technology. 3D printing equipment is widely used in molds, customized products, medical fixtures, prostheses and other fields due to its high molding precision.

[0003] In order to achieve high-precision printing of 3D printing equipment, it is necessary to perform optical calibration on the 3D printing equipment. The principle of optical calibration is to compare the difference between the marking points projected by the 3D printing equipment and the calibration points on the calibration plate, and correct the marking points projected by the 3D printing equipment based on this difference. Therefore, the accuracy of the calibration plate directly determines the accuracy of 3D printing.

[0004] Currently, 3D printing equipment generally uses metal, ceramic or glass calibration plates. However, the calibration point accuracy of metal and ceramic calibration plates is not high, and glass calibration plates are prone to reflection and refraction problems. When using a camera to shoot the marking points projected by the 3D printing equipment and the calibration points on the calibration plate, it is easy to fail to shoot or shoot unclearly.

[0005] Therefore, under the condition of ensuring the accuracy of the calibration points, it is urgent to solve the problems of calibration plate reflection, refraction and ambient light interference in the 3D printing calibration process. Summary of the invention

[0006] The technical problem solved by the present invention is to provide an optical calibration tool, a 3D printing device and a 3D printing optical calibration method, which can solve the problems of reflection, refraction and ambient light interference of the calibration plate during the 3D printing calibration process.

[0007] To solve the above technical problems, an embodiment of the present invention provides an optical calibration tool, including: an illumination part; a calibration plate, the calibration plate including a calibration plate substrate and calibration points, wherein the calibration plate substrate has a first surface and a second surface relative to each other, the calibration points are arranged on the first surface of the calibration plate substrate, and the second surface of the calibration plate substrate faces the illumination part; a coating, the coating covers the first surface of the calibration plate substrate, and the surface roughness of the coating is higher than the surface roughness of the calibration plate substrate.

[0008] Optionally, it also includes: a supporting portion, which includes a base plate and a supporting member perpendicular to the base plate, the supporting member and the base plate form a accommodating space, the top of the accommodating space is open, and the opening faces the second surface of the calibration plate substrate.

[0009] Optionally, the support member includes a plurality of side plates or columns of the same height, and the side plates or columns are used to support the calibration plate, and the calibration plate is parallel to the bottom plate of the support portion.

[0010] Optionally, the illumination unit is installed in the accommodating space, and the illumination range of the illumination unit at least covers the calibration point.

[0011] Optionally, the lighting unit includes a plurality of LED lamps.

[0012] Optionally, the illumination unit further includes a plurality of light strips, and the plurality of LED lights are fixed on the light strips.

[0013] Optionally, a light-scattering plate is further provided between the illumination part and the calibration plate, and the light-scattering plate makes the light emitted by the illumination part diffuse evenly onto the calibration plate.

[0014] Optionally, the calibration plate substrate is made of glass, resin or plastic.

[0015] Optionally, the covering film includes a colored plastic film or a paper film.

[0016] Optionally, the material of the light-diffusing plate includes polycarbonate or polymethyl methacrylate.

[0017] Optionally, it further includes: a leveling mechanism, which is arranged on the supporting part and makes the calibration plate parallel to the horizontal plane.

[0018] Optionally, the illumination unit further comprises a control device for controlling the on / off state of the illumination unit.

[0019] Optionally, the control device can also be used to adjust the brightness of the illumination part.

[0020] An embodiment of the present invention further provides a 3D printing device, comprising: the above-mentioned optical calibration tool; a stage for placing the optical calibration tool; and a light projector for projecting marking points on the coating.

[0021] An embodiment of the present invention also provides a 3D printing optical calibration method, comprising: providing the above-mentioned 3D printing device; placing the optical calibration tool on the stage, adjusting the optical calibration tool so that the calibration plate is parallel to the horizontal plane; turning on the illumination part to image the calibration point on the coating; photographing the image of the calibration point on the coating to obtain a calibration point image; turning off the illumination part, and projecting the marking point of the 3D printing device on the coating with the light projector; photographing the image of the marking point on the coating to obtain a marking point image; comparing the calibration point image with the marking point image to realize calibration of the 3D printing device.

[0022] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0023] A layer of coating is covered on the first surface of the calibration plate substrate. Since the calibration points are set on the first surface, the coating covers the side for obtaining the calibration point image, and the surface roughness of the coating is higher than the surface roughness of the calibration plate substrate. When the calibration points on the calibration plate or the marking points projected by the 3D printing device are photographed by a camera, the light source of the 3D printing device or other ambient light will be diffusely reflected on the coating instead of directly irradiating the calibration plate substrate to produce mirror reflection, which can weaken the interference of the reflection or refraction phenomenon of the calibration plate substrate on the image acquisition, thereby obtaining clear calibration point and marking point images; in addition, the calibration points on the calibration plate are imaged on the coating through the illumination unit, and the clarity of the calibration points will not be affected by the existence of the coating, and the image of the calibration points of the calibration plate can still be clearly photographed, thereby solving the problem of unclear camera shooting due to reflection, refraction and ambient light interference of the calibration plate during the calibration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a structural exploded view of an optical calibration tool provided by an embodiment of the present invention;

[0025] Figure 2 yes Figure 1 Schematic diagram of the structure of the calibration plate in the provided optical calibration tooling. DETAILED DESCRIPTION

[0026] As can be seen from the background technology, in order to ensure the accuracy of 3D printing, the 3D printing equipment needs to be optically calibrated before printing. The currently commonly used optical calibration method is to use a camera to shoot the marking points projected by the 3D printing equipment and the calibration points on the calibration plate, and compare them.

[0027] Since the calibration point accuracy of the glass calibration plate is high and the cost of glass material is low, the glass calibration plate is usually used for optical calibration. Usually, the glass calibration plate includes a glass calibration plate substrate and calibration points, and the glass calibration plate substrate includes a first surface and a second surface relative to each other. The calibration points are located on the first surface of the glass calibration plate substrate, and the first surface is the side for acquiring images. When performing optical calibration of the camera, the image of the calibration point is captured by the camera, but because the surface of the glass material is smooth and mirror reflection is prone to occur, when the external light source is irradiated on the glass, there will be strong reflected light or refracted light, which will interfere with the camera shooting, resulting in the camera being unable to shoot or unable to clearly shoot the calibration points on the glass calibration plate; similarly, when shooting the marking points projected by the 3D printing device, the light source of the 3D printing device is required to project the marking points on the first surface of the glass calibration plate substrate. The light source of the 3D printing device will also cause strong reflection and refraction when irradiated on the glass, resulting in the camera being unable to clearly shoot the marking points projected by the 3D printing device, which directly leads to low accuracy of optical correction, thereby affecting the accuracy of the 3D printing device.

[0028] In order to solve the above problems, the inventor provides an optical calibration tool, in which the calibration points are set on the first surface of the calibration plate substrate, the second surface of the calibration plate substrate faces the illumination part, and the coating covers the first surface. The marking points projected by the 3D printing device are directly projected onto the coating, and the calibration points in the calibration plate can be clearly imaged on the coating through the illumination part. When performing optical calibration, the camera shoots the coating surface, and because of the existence of the coating, and the surface roughness of the coating is higher than the surface roughness of the calibration plate substrate, diffuse reflection will occur when the light source is irradiated on the coating, and there will be no strong reflected light. The light source of the 3D printing device and other external light sources will not directly irradiate the calibration plate, which weakens the reflection and refraction problems of the calibration plate. The camera can clearly capture the marking points projected by the 3D printing device and the calibration points of the calibration plate, ensuring the accuracy of the optical calibration.

[0029] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Figure 1 It is a structural exploded view of an optical calibration tool provided in one embodiment of the present invention.

[0031] Figure 2 yes Figure 1 A schematic diagram of the structure of a calibration plate in the provided optical calibration tooling, wherein the arrow indicates the direction of light emitted by the illumination unit.

[0032] Combined with reference Figure 1 and Figure 2The optical calibration tool 1 includes: an illumination unit 10; a calibration plate 20, wherein the calibration plate 20 includes a calibration plate substrate 21 and calibration points 22, wherein the calibration plate substrate 21 has a first surface 211 and a second surface 212 relative to each other, and the calibration points 22 are arranged on the first surface 211 of the calibration plate substrate 21, and the second surface 212 of the calibration plate substrate 21 faces the illumination unit 10; a coating 30, wherein the coating 30 covers the first surface 211 of the calibration plate substrate 21, and the surface roughness of the coating 30 is higher than the surface roughness of the calibration plate substrate 21.

[0033] The calibration plate 20 is used for optical calibration of the 3D printing device, and the calibration points 22 in the calibration plate 20 are used as calibration references in optical calibration. The calibration points 22 are arranged on the first surface 211 of the calibration plate substrate 21. During camera optical calibration, the first surface 211 is used as the side photographed by the camera. Since the first surface 211 is covered with a coating 30, the side of the coating 30 facing away from the calibration plate 20 is the side photographed by the camera.

[0034] In this embodiment, the calibration plate substrate 21 is a glass substrate, and the calibration points 22 are two-dimensional plane graphics. By laser engraving in the glass substrate, high-precision calibration points can be obtained, thereby improving the accuracy of optical calibration and the printing accuracy of 3D printing equipment. In addition, the price of the glass substrate is low, which can save costs.

[0035] In other embodiments, the calibration plate substrate 21 may also be made of resin, plastic, or other materials.

[0036] In this embodiment, the calibration points 22 are colored blocks, which are opaque structures and are disposed on the first surface 211 of the calibration plate substrate 21 .

[0037] In this embodiment, the illumination unit 10 includes a plurality of LED (Light Emitting Diode) lamps; in other embodiments, the illumination unit 10 may also include other lamps that can emit a stable light source, such as incandescent lamps. LED lamps have the advantages of high brightness, long light projection, and energy saving, and can better project the calibration point 22 onto the coating.

[0038] In this embodiment, the illumination unit 10 further includes a plurality of light strips, and the plurality of LED lights are fixed on the light strips. By fixing the LED lights with the light strips, the assembly of the illumination unit 10 can be facilitated, so that the light emitted by the illumination unit 10 during the optical calibration process is relatively stable.

[0039] In other embodiments, the illumination unit 10 may not include a light strip, and the plurality of LED lights may be directly fixed at desired positions.

[0040] In this embodiment, the illumination unit 10 further includes a control device (not shown), and the control device can control the switch of the illumination unit 10 .

[0041] Because the main function of the illumination unit 10 is to image the calibration points on the calibration plate on the coating, when photographing the calibration points on the calibration plate, the illumination unit is turned on to emit light, and the illumination unit can be turned off in the rest of the process to save energy.

[0042] In this embodiment, the control device can also control the brightness of the illumination unit 10. When different cameras are used for calibration, different light intensities are required. Therefore, the brightness of the illumination unit 10 can be adjusted by the control device to adapt to different cameras, so that the camera has a better shooting effect, thereby improving the calibration accuracy.

[0043] In this embodiment, the control device is connected to the illumination unit 10 through an electric wire, and controls the switch or brightness of the illumination unit by controlling the on-off of the circuit and the magnitude of the current.

[0044] In this embodiment, the surface roughness of the coating 30 is higher than the surface roughness of the calibration plate substrate 22 .

[0045] Light will be diffusely reflected on the surface of an object with high surface roughness, and will be specularly reflected on the surface of an object with low surface roughness and very smooth, and the reflected light will be strong. The surface roughness of the coating 30 is relatively high, and the light source of the 3D printing device or the external light source is diffusely reflected on the coating, and there will be no strong reflection phenomenon, which weakens the adverse effect of the reflection problem of the calibration plate substrate 22 on the camera photography.

[0046] In this embodiment, the coating 30 must have a certain light transmittance, because the calibration point 22 of the calibration plate 20 is projected onto the coating 30 through the illumination unit 10. If the coating is made of a material that is opaque or has poor light transmittance, the image of the calibration point 22 on the coating 30 cannot be displayed on the side of the coating 30 that faces away from the calibration plate 20, and the camera cannot clearly capture the image of the calibration point 22. However, the light transmittance of the coating 30 cannot be too high, because too high light transmittance results in poor effect in weakening the reflection phenomenon of the calibration plate substrate 21.

[0047] The coating 30 is a material on the surface of which light is diffusely reflected, including a colored plastic film or a paper film.

[0048] In this embodiment, the calibration point 22 is arranged on the first surface 211 of the calibration plate substrate 21, the illumination unit 10 faces the second surface 212 of the calibration plate substrate 21, the coating 30 covers the first surface 211, and when light is irradiated from the second surface 212 and passes through the calibration plate substrate 21, the distance between the calibration point 22 and the coating 30 is close, so that the imaging of the calibration point 22 on the coating 30 can be made clearer.

[0049] In this embodiment, when the optical calibration tool is performing optical calibration, the illumination unit 10 irradiates the second surface of the calibration plate substrate 21, and projects the calibration point 22 in the calibration plate 20 onto the coating 30 covering the first surface of the calibration plate substrate 21. Since the coating 30 is light-transmissive, the calibration point 22 can be clearly imaged on the coating 30. When the 3D printing device projects the marking point, it is directly projected onto the coating 30. Since the coating 30 is a material on which light will be diffusely reflected, there will be no strong reflection and refraction effects. The light source or other ambient light of the 3D printing device will not interfere with the camera shooting. Therefore, the camera can clearly capture the calibration point 22 of the calibration plate 20 imaged on the coating 30 and the marking point projected by the 3D printing device, and compare them to calibrate the 3D printing device, thereby improving the printing accuracy of the 3D printing device.

[0050] Continue to refer Figure 1 The optical calibration tool 1 further includes: a support portion 40 , wherein the support portion 40 includes a base plate 41 and a support member 42 perpendicular to the base plate 41 .

[0051] In this embodiment, the bottom plate 41 and the support member 42 form a receiving space 43 . The top of the receiving space 43 is open, and the opening faces the second surface 212 of the calibration plate substrate 21 .

[0052] In this embodiment, the illumination unit 10 is installed in the accommodating space 43. Specifically, the illumination unit 10 is installed on the bottom plate 41 of the accommodating space 43. The opening at the top of the accommodating space 43 allows the light emitted by the illumination unit 10 to illuminate the calibration plate.

[0053] In this embodiment, a control device for controlling the illumination unit 10 is installed on the support unit 40 .

[0054] Since all the calibration points 22 need to be imaged on the coating 30 during calibration, the illumination range of the illumination unit 10 must at least cover all the calibration points 22 , and thus the size of the opening must at least accommodate all the calibration points 22 .

[0055] In this embodiment, the support member 42 includes a plurality of side plates of the same height. The side plates are arranged along the periphery of the bottom plate 41 and are perpendicular to the bottom plate 41 .

[0056] The side panels and the bottom panel 41 may be detachable or integrally formed. When the side panels and the bottom panel 41 are integrally formed, the support portion 40 as a whole is a box body with an opening at the top.

[0057] In this embodiment, the side panels are used to support the calibration plate 20 , and the calibration plate 20 is directly placed on the side panels. Since the heights of the side panels are the same, the calibration plate 20 and the bottom plate 41 of the support portion 40 are parallel.

[0058] The advantage of the calibration plate 20 being in direct contact with the support part 40 is that, on the one hand, the calibration plate is closer to the illumination part, and the light intensity emitted by the illumination part is sufficient to make the imaging of the calibration point clearer; on the other hand, in the actual calibration process, the calibration plate needs to be adjusted to a state parallel to the horizontal plane, and the state of the calibration plate can be adjusted by directly adjusting the support part.

[0059] In other embodiments, the support member 42 may also be a plurality of columns of the same height (not shown), and the columns may be disposed at the corners of the base plate 41 to support the calibration plate 20 .

[0060] Continue to refer Figure 1 A light homogenizing plate 11 is further provided between the illumination unit 10 and the calibration plate 20 .

[0061] The light scattering plate 11 can evenly diffuse the light emitted by the illumination unit 10 onto the calibration plate 20, thereby improving the camera's shooting quality. Due to the arrangement of the light scattering plate 11, the position distribution of the illumination unit 10 in the accommodation space 43 does not need to be specifically limited, as long as the illumination range can cover all the calibration points 22.

[0062] In this embodiment, the light homogenizing plate 11 is made of polycarbonate; in other embodiments, the light homogenizing plate 11 may also be made of polymethyl methacrylate.

[0063] In this embodiment, the light homogenizing plate 11 is directly placed on the support member 42 , and then the calibration plate 20 is placed on the light homogenizing plate 11 .

[0064] Continue to refer Figure 1 The optical calibration tool 1 also includes a leveling mechanism 50, and the leveling mechanism 50 is used to make the calibration plate 20 parallel to the horizontal plane.

[0065] Because the calibration plate and the printing surface of the 3D printing device need to be on the same horizontal plane when the 3D printing device is working, it is necessary to adjust the calibration plate 20 to make it parallel to the printing surface of the 3D printing device.

[0066] In this embodiment, the leveling mechanism 50 is installed on the base plate 41 of the support part 40. Since the calibration plate 20 is parallel to the base plate 41, the base plate 41 is adjusted to be parallel to the horizontal plane. Accordingly, the calibration plate 20 is parallel to the horizontal plane, and the printing surface of the 3D printing device is always in a horizontal state, so that the calibration plate 20 is parallel to the printing surface of the 3D printing device.

[0067] In this embodiment, the leveling mechanism 50 includes a plurality of height-adjustable columns.

[0068] It should be noted that a space for placing a level is reserved on the bottom plate 41 of the support portion 40. When performing the leveling operation, the level is placed on the bottom plate 41, and the entire optical calibration tool 1 is placed on the workbench of the 3D printing device. By adjusting the height of the column of the leveling mechanism 50, when the level shows horizontal, it means that the bottom plate 41 is parallel to the horizontal plane.

[0069] Through the leveling mechanism 50, the optical calibration tool 1 can also be used in some 3D printing devices whose working surfaces are not flat or level, thereby solving the problem of low calibration accuracy caused by the calibration plate and the printing surface not being parallel due to the uneven working surface.

[0070] Accordingly, an embodiment of the present invention further provides a 3D printing device (not shown), the 3D printing device comprising: Figure 1 and Figure 2 The optical calibration tool shown in the figure; a stage for placing the optical calibration tool; and a light projector for projecting marking points on the coating. The optical calibration tool has high calibration accuracy, thereby improving the printing accuracy of the 3D printing device.

[0071] An embodiment of the present invention also provides a 3D printing optical calibration method, comprising: providing the above-mentioned 3D printing device; placing the optical calibration tool on the stage, adjusting the optical calibration tool so that the calibration plate is parallel to the horizontal plane; turning on the illumination part to image the calibration point on the coating; photographing the image of the calibration point on the coating to obtain a calibration point image; turning off the illumination part, and projecting the marking point of the 3D printing device on the coating with the light projector; photographing the image of the marking point on the coating to obtain a marking point image; comparing the calibration point image with the marking point image to realize calibration of the 3D printing device.

[0072] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A 3D printing optical calibration method, characterized in that: include: A 3D printing device is provided, the 3D printing device comprising an optical calibration tool, a stage for placing the optical calibration tool, and a light projector for projecting marking points on a coating, wherein the optical calibration tool comprises: an illumination unit; a calibration plate, the calibration plate comprising a calibration plate substrate and calibration points, wherein the calibration plate substrate has a first surface and a second surface opposite to each other, the calibration points are arranged on the first surface of the calibration plate substrate, and the second surface of the calibration plate substrate faces the illumination unit; a coating, the coating covers the first surface of the calibration plate substrate, the coating The surface roughness of the calibration plate substrate is higher than that of the calibration plate substrate; a support portion, the support portion includes a bottom plate and a support member perpendicular to the bottom plate, the support member includes a plurality of side plates or columns of the same height, the side plates or columns are used to support the calibration plate, the calibration plate is parallel to the bottom plate of the support portion, the support member and the bottom plate form a receiving space, the top of the receiving space is open, the opening faces the second surface of the calibration plate substrate, the illumination portion is installed in the receiving space, and the illumination range of the illumination portion at least covers the calibration point; Placing the optical calibration tool on the stage, and adjusting the optical calibration tool so that the calibration plate is parallel to a horizontal plane; Turning on the illumination unit to image the calibration point on the coating; Taking an image of the calibration point on the coating to obtain an image of the calibration point; The illumination unit is turned off, and the light projector projects a marking point of a 3D printing device onto the coating; photographing the image of the marking point on the covering film to obtain an image of the marking point; The calibration point image and the marking point image are compared to achieve optical calibration of the 3D printing device.

2. The 3D printing optical calibration method according to claim 1, characterized in that: The lighting unit includes a plurality of LED lamps.

3. The 3D printing optical calibration method according to claim 2, characterized in that: The illumination unit further comprises a plurality of light strips, and the plurality of LED lights are fixed on the light strips.

4. The 3D printing optical calibration method according to claim 1, characterized in that: A light-diffusing plate is further arranged between the illumination part and the calibration plate, and the light-diffusing plate makes the light emitted by the illumination part diffuse evenly onto the calibration plate.

5. The 3D printing optical calibration method according to claim 1, characterized in that: The calibration plate substrate is made of glass or resin.

6. The 3D printing optical calibration method according to claim 1, characterized in that: The covering film comprises a colored plastic film or a paper film.

7. The 3D printing optical calibration method according to claim 4, characterized in that: The material of the light-diffusing plate includes polycarbonate or polymethyl methacrylate.

8. The 3D printing optical calibration method according to claim 1, characterized in that: Also includes: A leveling mechanism is provided on the supporting portion, and the leveling mechanism makes the calibration plate parallel to a horizontal plane.

9. The 3D printing optical calibration method according to claim 1, characterized in that: The illumination unit also has a control device for controlling the on / off state of the illumination unit.

10. The 3D printing optical calibration method according to claim 9, characterized in that: The control device can also be used to adjust the brightness of the illumination part.

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