CN113492526B

CN113492526B - Three-dimensional printer and manufacturing method thereof

Info

Publication number: CN113492526B
Application number: CN202010247926.6A
Authority: CN
Inventors: 陈昭舜; 黄家斌; 郑凯云
Original assignee: Young Optics Inc
Current assignee: Young Optics Inc
Priority date: 2020-04-01
Filing date: 2020-04-01
Publication date: 2024-01-19
Anticipated expiration: 2040-04-01
Also published as: CN113492526A

Abstract

A three-dimensional printer comprises a projector, a trough and a forming platform. The projector includes a light source, a digital micromirror device, and a controller. The digital micromirror device includes micromirrors that are switchable between an on state and an off state according to a control signal. The controller is electrically connected with the digital micromirror device and the light source and comprises a judging unit. The judging unit can output a control signal to switch the micro mirror to the off state when the light source is in the off state. The forming platform is adjacent to the trough. In addition, a manufacturing method of the three-dimensional printer is also provided.

Description

Three-dimensional printer and manufacturing method thereof

Technical Field

The present invention relates to a three-dimensional printer and a method for manufacturing the same, and more particularly, to a digital light processing three-dimensional printer and a method for manufacturing the same.

Background

In a conventional three-dimensional printer, a projection device is used to emit a light beam to irradiate a photosensitive resin for a period of time, and the photosensitive resin is hardened on a printing platform due to the irradiation of the light beam, so as to form one layer in a workpiece. However, in a projection apparatus employing digital light processing (Digital Light Processing, DLP) technology, a digital micromirror device is generally disposed therein, and each pixel of the digital micromirror device is generally composed of a tiny micromirror, and each micromirror has three rotational positions, one is a bright state (On state) that reflects light to a projection lens, the other is a dark state (Off state) that deflects light away from the projection lens, the last is a non-deflected state (flat state) of the micromirror, and the micromirror controls switching between the three states by a pivot (hinge) to project light in a predetermined direction.

However, when the projection device projects a fixed screen for a long time, the pivot shafts of the micromirrors are in the same state for a long time, so that the micromirrors face the same position. The memory effect of the pivot causes the condition of screen white point or dead point, which results in poor printing quality of the three-dimensional printer and short service life of the digital micromirror device.

Disclosure of Invention

The invention provides a three-dimensional printer which has good printing quality and reliability.

The invention provides a manufacturing method of a three-dimensional printer, which is used for producing the three-dimensional printer.

The embodiment of the invention provides a three-dimensional printer which comprises a projector, a trough and a forming platform. The projector includes a light source, a digital micromirror device, and a controller. The digital micromirror device is disposed optically downstream of the light source. The digital micromirror device includes micromirrors that are switchable between an on state and an off state according to a control signal. The controller is electrically connected with the digital micromirror device and the light source and comprises a judging unit. The controller is electrically connected with the digital micromirror device and the light source and comprises a judging unit. The judging unit can output a control signal when the light source is in a closed state so as to switch the micro mirror of the digital micro mirror unit into the closed state, and the trough is arranged at the optical downstream of the projector. The forming platform is adjacent to the trough.

The embodiment of the invention provides a three-dimensional printer which comprises an ultraviolet light source, a digital micromirror device, a trough, a forming platform and a controller. The digital micro-mirror device is arranged at the downstream of the light path of the ultraviolet light source. The digital micromirror device includes a micromirror. The trough is arranged at the downstream of the light path of the digital micromirror device. The forming platform is adjacent to the trough. The controller is electrically connected with the digital micromirror device and the ultraviolet light source. The controller includes a recording unit and a judging unit. The recording unit can obtain the switch state of the micromirror. When the ultraviolet light source is turned off, the judging unit can switch the micromirror to the on-off state.

The embodiment of the invention provides a manufacturing method of a three-dimensional printer, which comprises the following steps: providing a projector, wherein the projector comprises a light source, a digital micro-mirror device and a controller, the digital micro-mirror device is arranged at the downstream of a light path of the light source, the digital micro-mirror device comprises a micro-mirror, the micro-mirror can be switched between an on state and an off state according to a control signal, the controller is electrically connected with the digital micro-mirror device and the light source, the controller comprises a judging unit, and the judging unit can output the control signal to switch the micro-mirror of the digital micro-mirror device into the off state when the light source is in the off state; a trough is provided and is arranged at the downstream of the optical path of the projector. A forming table is provided adjacent the trough.

Based on the above, in the three-dimensional printer according to the embodiment of the present invention, when the light source is turned off, the on/off state of the switching micromirror is adjusted so that the time ratio of the on state to the off state of the micromirror tends to be consistent, and therefore, the three-dimensional printer according to the embodiment of the present invention can have good manufacturing quality and good reliability. In addition, the embodiment of the invention further provides a manufacturing method for manufacturing the three-dimensional printer.

The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention, as well as the preferred embodiments thereof, together with the following detailed description of the invention, given by way of illustration only, together with the accompanying drawings.

Drawings

Fig. 1 is a schematic architecture diagram of a three-dimensional printer according to an embodiment of the invention.

Fig. 2 is a schematic top view of the digital micromirror device of fig. 1.

Fig. 3A-3C are schematic diagrams of different states of a micromirror in a digital micromirror device.

Fig. 4A to 4D are different operation timing diagrams of the light source and the dmd of the three-dimensional printer of fig. 1.

FIG. 5 is a graph of the operating state time ratio versus the maximum recommended operating temperature for a micromirror at a fixed lifetime.

Fig. 6 is a flow chart of steps of a method of manufacturing a three-dimensional printer.

Detailed Description

Fig. 1 is a schematic architecture diagram of a three-dimensional printer according to an embodiment of the invention. Fig. 2 is a schematic top view of the digital micromirror device of fig. 1. Fig. 3A-3C are schematic diagrams of different states of a micromirror in a digital micromirror device.

Referring to fig. 1, in this example, a three-dimensional printer 100 includes a projector 110, a trough 120, and a forming platform 130. The projector 110 is used to project an image beam IMB, which is a digital light processing (digital light processing, DLP) projector. Projector 110 further includes a light source 112, a digital micromirror device 114, a projection lens 116, and a controller 118. The trough 120 is used for containing the photo-curing material 10, wherein the photo-curing material 10 may be in a liquid state, a colloidal state, a fluid state or a powder state. In this example, the photo-curable material 10 is in a liquid state. Due to material properties, the photocurable material 10, after curing by irradiation, can form a workpiece OB. The controller 118 further includes a recording unit 118a, a judging unit 118b and a data unit 118c. The above elements are described in detail in the following paragraphs.

The light source 112 is a light emitting element capable of emitting an illumination beam IB, and the light emitting element is, for example, a light emitting diode (light emitting diode, LED), a Laser Diode (LD), or other suitable light emitting element. The wavelength range of the light provided by the light emitting element is matched with the light curable material 10, and in this example, the light source 112 is an ultraviolet light source, and the projector 110 is a DLP projector of ultraviolet light.

Referring to fig. 2, the digital micromirror device 114 includes a plurality of micromirrors M. The micromirrors M are arranged in an array. Referring to fig. 3A to 3C, each micromirror M is adapted to swing back and forth by the pivot H to switch between a non-deflected state (flat state), an on state (on state), and an off state (off state). In this example, the pivots H of the micromirrors M are substantially parallel to each other.

Referring to FIG. 3A, when the micromirror M is in an undeflected state, the micromirror M is in position P ₀ And an angle of 0 degrees with the horizontal reference axis RS. Referring to FIG. 3B, when the micromirror is in an on state, the micromirror M is rotated by the pivot H to place the micromirror M in the position P ₁ Such that it forms a non-zero angle θ with the horizontal reference axis RS (angle θ is, for example, in the range of +12 degrees to +17 degrees). Therefore, the illumination beam IB from the light source 112 is reflected by the micromirror M to the projection lens 116, and the ON state of the micromirror M is also controlledThe bright state (On state). Referring to FIG. 3C, when the micromirror M is in a turned-off state, the micromirror M is rotated by the pivot H to place the micromirror M in the position P ₂ Such that it forms a non-zero angle θ with the horizontal reference axis RS (angle θ is, for example, in the range of-12 degrees to-17 degrees). The illumination beam IB from the light source 112 is reflected Off the projection lens 116 by the micromirror M, and the Off state of the micromirror M is also called dark state (Off state).

The projection lens 116, for example, includes a combination of one or more optical lenses having diopters, and the trough 120, for example, is a receiving trough, in this example, the trough 120 has a transparent bottom 122 for allowing light beams to penetrate, but the material of the trough 120 is not limited to glass, and may be made of, for example, a light-transmissive polymer material such as resin or plastic.

The controller 118 may be a computer, microprocessor (Micro Controller Unit, MCU), central processing unit (Central Processing Unit, CPU), or other programmable controller (Microprocessor), digital signal processor (Digital Signal Processor, DSP), programmable controller, application specific integrated circuit (Application Specific Integrated Circuits, ASIC), programmable logic device (Programmable Logic Device, PLD), or other similar device.

The forming table 130 can move in a vertical direction away from or near the bottom 122 of the trough 120. The photo-curable material 10 is cured by irradiation to form a workpiece OB, which may be formed layer by layer on the modeling platform 130.

In this example, the controller 118 is electrically connected to the dmd 114 and the light source 112. In addition, the controller 118 has unit modules for performing different functions, specifically, the controller 118 includes a recording unit 118a, a judging unit 118b and a data unit 118c, wherein the recording unit 118a is used for obtaining the on/off state of the micromirror M. The judging unit 118b switches the on/off state of the micromirror M according to a specific condition, and the judging basis of the judging unit 118b will be described in detail in the following paragraphs. The data unit 118c stores the design data of the 3D model.

The configuration relationships between the elements will be described in detail in the following paragraphs.

Referring to fig. 1, a digital micromirror device 114 is disposed downstream of the light path of the light source 112. A projection lens 116 is disposed downstream of the digital micromirror device 114 in the optical path. The trough 120 is disposed downstream of the optical path of the projector 110. Light is transmitted from upstream to downstream of the optical path. Thus, the optical path downstream of an element is understood to be the portion of the optical path after light passes through the element. For example, the optical path downstream of the light source 112, which is the optical path after light is emitted from the light source 112, is referred to as the optical path downstream of the light source 112, and so on. The forming table 130 is adjacent to the trough 120.

Fig. 4A to 4D are different operation timing diagrams of the light source and the dmd of the three-dimensional printer of fig. 1. FIG. 5 is a graph of the operating state time ratio versus the maximum recommended operating temperature for a micromirror at a fixed lifetime. The following paragraphs will be described with reference to fig. 1, 4A to 4D and 5 to illustrate the operation and the corresponding technical effects of the three-dimensional printer 100.

Referring to fig. 4A to 4D, different timings are divided into a pre-operation timing T in fig. 4A to 4D ₀ A plurality of first time sequences T ₁ And a plurality of second time sequences T ₂ Wherein the first time sequences T ₁ And these second time sequences T ₂ Alternating with each other.

Referring to FIG. 4A, the timing T is shown before operation ₀ In the off state of the three-dimensional printer 100, the light source 112 is off, and the micromirrors M within the dmd 114 are in the undeflected state as in fig. 3A.

At a first time sequence T ₁ (i.e. t ₁ Second to t ₂ Second), the three-dimensional printer 100 is turned on, the light source 112 and the dmd 114 are turned on to print the workpiece OB, and thus the first timing T ₁ Also referred to as printing timing. In detail, at the first time T ₁ The light source 112 emits the illumination beam IB and then transmits the illumination beam IB to the digital micromirror device 114, and the controller 118 sends a control signal G to the digital micromirror device 114 according to the 3D design data stored in the data unit 118c to determine which positions the micromirrors M are respectively located, wherein a part of the micromirrors M may be in an on state and a part of the micromirrors M may be in an off stateA state. In fig. 4A, the micromirror M is taken as an example of an on state, and the recording unit 118a records the on-off state of the micromirror M. Since the states of the micromirrors M are determined according to the 3D design data, when the illumination beam IB irradiates the micromirrors M, the micromirrors M in the on state reflect part of the illumination beam IB' to the projection lens 116 to form the image beam IMB, and the image beam IMB penetrates the bottom 122 of the trough 120 through the projection lens 116 to irradiate the photo-curing material 10, so that the photo-curing material 10 is cured to form the cross-sectional layer SL of the workpiece OB after being irradiated with light for a period of time. On the other hand, the micromirror M in the undeflected state or the off state reflects a portion of the illumination light beams IB ", IB'" away from the projection lens 116, respectively.

At the second time sequence T ₂ (i.e. t ₂ Second to t ₃ Second), the three-dimensional printer 100 is also turned on, when the cross-sectional layer SL is formed, the light source 112 is turned off, and the forming stage 130 is moved in a direction approaching or separating from the trough 120 (i.e., the forming stage 130 is in a moving state) to move the forming stage 130 to a printing position ready for printing the next cross-sectional layer SL, so that the second timing T is a second timing ₂ May also be referred to as a ready sequence. At this time, the determining unit 118B determines that the light source 112 is turned off and the molding stage 130 is moving, and outputs a control signal G to control the micromirror M to switch from the on state of fig. 3B to the off state as in fig. 3C.

On the other hand, referring to fig. 4A again, the above paragraphs and fig. 4A use a part of the micromirrors M at the first time T ₁ The internal is initially in an on state and then switched to an off state. In other embodiments, if a portion of the micromirrors M are at a first time T ₁ When the first time is in the off state, the determining unit 144 at the second time T ₂ The micromirror M is then switched from the off state of fig. 3C to the on state as in fig. 3B.

Referring to fig. 5, the horizontal axis in fig. 5 represents an operating state time ratio R, and the vertical axis is a maximum recommended operating temperature, wherein the operating state time ratio R is defined as the following formula (1):

wherein, 0/100 and 100/0 respectively represent: the micromirrors M are all in the off state and the micromirrors are all in the on state, 40/60, 60/40 are respectively represented as: the time when the micromirror M is in the on state and the time when it is in the off state are 40: 60. 60:40, and the like. It should be noted that the operating state time ratio R does not take into account the time that the micromirror M is in the undeflected state. Taking the point a of fig. 5 as an example, the point a represents that, under the fixed service life, if the operating state time ratio R of the micromirror M is 0/100 or 100/0, the maximum recommended operating temperature is 40 degrees celsius, and the like. Thus, as can be seen from fig. 5: if the operating state time ratio R is unbalanced (e.g., 0/100 or 100/0), the smaller the maximum recommended operating temperature (e.g., 40 degrees celsius), the more severe the temperature specification required for the micromirror M and the higher order heat dissipation specification are required, but it is difficult to achieve such operating temperature in the general operating state. If the operating state time ratio R tends to be balanced (e.g., tends to be 50/50), the maximum recommended operating temperature is larger (e.g., 70 degrees celsius), the temperature specification required by the micromirror M is more abundant, and the three-dimensional printer can be matched with a lower-order heat dissipation specification.

As described above, referring to fig. 4A and 5, in the three-dimensional printer 100 of the present embodiment, the first timing T of printing the workpiece OB ₁ The recording unit 118a can record the first time period T of the micromirror M ₁ In a second timing T of turning off the light source 112 and moving the molding stage 130 (e.g., as in the ON state of FIGS. 3B and 4A) ₂ When the determining unit 118b outputs the control signal G to switch the on/off state of the micromirror M (e.g. to the off state as in fig. 3C), so that the time ratio of the on state to the off state of the micromirror M can be adjusted to be consistent, the pivot H of the micromirror M is less likely to have a memory effect, and the projector 110 does not cause a white spot or dead spot, so that the three-dimensional printer 100 has good printing quality. And according to the figure5 it is clear that if the operating time ratio R tends to be consistent, the temperature specification of the maximum recommended operating temperature of the digital micromirror device 114 can be more abundant, and the digital micromirror device 114 has longer service life and better reliability.

Referring to fig. 4B, fig. 4B shows another way for the determining unit 144 to control the state of the micromirror. The micromirror M of fig. 4B operates in a similar manner to that of fig. 4A, with the main differences: at the second time sequence T ₂ At this time, the judgment unit 118c periodically switches the on-off state of the micromirror M. More specifically, at the second timing T ₂ The judgment unit 118c sets the micromirror M to be alternately switched between the on state and the off state at the same time t.

Referring to fig. 4C, fig. 4C shows another way of controlling the state of the micromirror by the determining unit 118C. The micromirror M of fig. 4C operates in a similar manner to that of fig. 4B, with the main differences: the judging unit 118c judges the first timing T ₁ For a duration of the on-off state of the micromirror M (e.g. t ₁ Seconds to t ₂ Second) to determine at the second time sequence T ₂ At this time, the period T' of the on-off state of the micromirror M. In detail, at the second timing T ₂ In this case, the judging unit 118c sets the duration of the turned-off state of the micromirror M to t ₂ -t ₁ Second, and also set the duration of the ON state of the micromirror M to t ₂ -t ₁ Second, in other words, the period of the switching state of the micromirror M is set to 2 (t ₂ -t ₁ ) Second.

Referring to fig. 4D, fig. 4D shows another way of controlling the state of the micromirror by the determining unit 118c. The micromirror M of fig. 4D operates in a similar manner to that of fig. 4A, with the main differences: at the second time sequence T ₂ At this time, the judgment unit 118c randomly (randomly) switches the on-off state of the micromirror M.

FIG. 6 is a flow chart of steps of a method of manufacturing a three-dimensional printer according to an embodiment of the invention.

Referring to fig. 6, the manufacturing method mainly includes the following three steps S100 to S300.

Step S100: the projector is provided, the projector includes a light source 112, a digital micromirror device 114 and a controller 118, the digital micromirror device 114 is disposed downstream of the light path of the light source 112, the digital micromirror device 114 includes a micromirror M, the micromirror M can be switched between an on state and an off state according to a control signal G, the controller 118 is electrically connected to the digital micromirror device 114 and the light source 112, the controller includes a judging unit 118b, and the judging unit 118b can output the control signal G to switch the micromirror M of the digital micromirror device 114 to the off state when the light source 112 is in the off state and the molding platform 130 is in the moving state.

Step S200: a trough 120 is provided, the trough 120 being located downstream of the optical path of the projector 110.

Step S300: a forming table 130 is provided adjacent the trough 120.

In summary, in the three-dimensional printer according to the embodiment of the present invention, the determining unit in the controller may switch the on/off state of the micromirror in a time interval in which the light source is turned off and the molding platform moves, so as to adjust the time ratio of the on state to the off state of the micromirror in the digital micromirror device, so that the two states tend to be consistent. Therefore, the pivot of the micromirror is less prone to memory effect, and the three-dimensional printer of the embodiments of the present invention can have good manufacturing quality and good reliability. In addition, the embodiment of the invention further provides a manufacturing method for manufacturing the three-dimensional printer.

While the invention has been described with respect to preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and that any such changes and modifications as described in the above embodiments are intended to be within the scope of the invention.

Claims

1. The utility model provides a three-dimensional printer which characterized in that includes a projector, a silo and a shaping platform, wherein:

the projector comprises a light source, a digital micro-mirror device and a controller, wherein:

the digital micro-mirror device is arranged at the downstream of the light path of the light source and comprises a micro-mirror which can be switched between an on state and an off state according to a control signal; and

the controller is electrically connected with the digital micromirror device and the light source and comprises a judging unit;

the trough is arranged at the downstream of the light path of the projector; and

the forming platform is adjacent to the trough, wherein the three-dimensional printer can execute printing in a first time sequence and execute a preparation program in a second time sequence, the judging unit is used for judging the state of the light source, and outputting the control signal when judging that the state of the light source is in a closed state, so that the micro mirror of the digital micro mirror device is switched to be in a switch state in the second time sequence.

2. The three-dimensional printer of claim 1, wherein when the light source is in an on state, the micromirror is in the on state or the off state according to the control signal.

3. The three-dimensional printer of claim 2, wherein when the light source is in an on state,

if the micromirror is in the on state according to the control signal, the judging unit may output another control signal when the light source is in the off state, switch the micromirror to the off state,

if the micromirror is in the off state according to the control signal, the judging unit may output another control signal when the light source is in the off state, and switch the micromirror to the on state.

4. The three-dimensional printer of claim 1, wherein the projector further comprises a projection lens disposed downstream of the light path of the digital micromirror device.

5. The three-dimensional printer of claim 1, wherein the trough is to contain a photo-curable material.

6. A three-dimensional printer, which is characterized by comprising an ultraviolet light source, a digital micromirror device, a trough, a molding platform and a controller, wherein:

the digital micro-mirror device is arranged at the downstream of the light path of the ultraviolet light source and comprises a micro-mirror;

the trough is arranged at the downstream of the light path of the digital micromirror device;

the molding platform is adjacent to the trough; and

the controller is electrically connected with the digital micro-mirror device and the ultraviolet light source, and comprises:

a recording unit for obtaining the switch state of the micromirror; and

the three-dimensional printer can execute printing in a first time sequence and execute a preparation program in a second time sequence, and the judging unit is used for judging the state of the ultraviolet light source and outputting a control signal when judging that the state of the ultraviolet light source is in a closed state so as to switch the micro mirror of the digital micro mirror device into the on-off state in the second time sequence.

7. The three-dimensional printer of claim 6, wherein the determining unit determines a period of the on-off state of the micromirror when the ultraviolet light source is turned off according to a duration of the on-off state of the micromirror when the ultraviolet light source is turned on.

8. The three-dimensional printer of claim 6, wherein the judging unit outputs the control signal to randomly switch the on-off state of the micromirror when the ultraviolet light source is turned off.

9. The three-dimensional printer of claim 6, wherein the trough is to contain a photo-curable material.

10. A method of manufacturing a three-dimensional printer, comprising:

providing a projector, wherein the projector comprises a light source, a digital micro-mirror device and a controller, the digital micro-mirror device is arranged at the downstream of a light path of the light source, the digital micro-mirror device comprises a micro-mirror, the micro-mirror can be switched between an on state and an off state according to a control signal, the controller is electrically connected with the digital micro-mirror device and the light source, and the controller comprises a judging unit;

providing a trough which is arranged at the downstream of the light path of the projector; and

providing a molding platform adjacent to the trough, wherein the three-dimensional printer can execute printing in a first time sequence and execute a preparation program in a second time sequence, the judging unit is used for judging the state of the light source, and outputting the control signal when judging that the state of the light source is in a closed state, so as to switch the micro mirror of the digital micro mirror device into a switch state in the second time sequence.