TWI430892B - Printing module used for a three dimensional prototyping apparatus - Google Patents

Description

Printing module suitable for three-dimensional forming mechanism

The present invention relates to a printing module, and more particularly to a printing module suitable for a three-dimensional forming mechanism.

Rapid Prototyping (RP technology) is developed based on the concept of stacking layers of pyramids. The main technical feature is the rapidity of molding. It can be used without any tools, molds and fixtures. Automatically and quickly convert any complex shape design into a 3D solid model.

At present, RP technology has developed a 3D solid model by using jet printing technology combined with the precise positioning technology of the carrier. The production method is to first lay a layer of powder on top of the carrier and spray it on part of the powder by inkjet printing technology. The high-viscosity adhesive liquid is printed to make the glue liquid adhere to the powder and solidify. The 3D solid model can be completed by repeating the above process layer stacking.

If the conventional flat jet printing technology is applied to a rapid three-dimensional forming machine, since the liquid discharge amount of the conventional flat printing technology is printed on the 2D drawing, the smaller the finer the spray point, the higher the resolution, but the higher the resolution. If applied to 3D molding, the amount of sprayed liquid sprayed by the 2D plane-specific printing nozzle is not enough to cover the surface of a solid powder particle, which will cause insufficient color saturation, due to the decision of 3D printing quality. Spray head and print In addition to the accuracy, the most important thing is the particle size of the powder to be printed. Please refer to the first figure, which is a schematic diagram of the structure of the powder particles to be printed on the microscopic surface, since the powder particles 11 are laid in the construction. When the platform 12 is to be printed, the powder particles 11 to be printed on the microscopic surface present a three-dimensional surface, so the required amount of printing liquid will far exceed the requirements for general printing, and the conventional planar printing technology is applied to In the 3D molding, the particle size of the powder particles 11 to be printed is 20-120 μm, and the printing head dedicated to the 2D plane has a pore size of about 15 μm or less when the resolution is 1200 Dpi. Therefore, the 2D plane is 2D plane. The amount of liquid sprayed by the dedicated print head at one time, the liquid 13 can cover only about 1/3 of the surface area of a solid powder particle 11 (as shown in the second figure). Therefore, the conventional practice is the same. The powder particles 11 are printed multiple times in order to make the finished product bright and delicate, which causes waste of time, multiple printing causes color discontinuity, resulting in poor printing quality and relatively short life of the printing head. .

Therefore, how to develop a printing module suitable for a three-dimensional forming mechanism which can improve the above-mentioned conventional technology is an urgent problem to be solved.

The main purpose of the present invention is to provide a printing module suitable for a three-dimensional forming mechanism, which solves the problem that the amount of liquid sprayed by a conventional printing nozzle dedicated to a 2D plane can cover only one third of a solid powder particle. The surface area needs to be printed multiple times on the same powder particle, which causes waste of time, multiple printing causes color discontinuity, resulting in poor printing quality and relatively short printhead life.

In order to achieve the above object, a broader embodiment of the present invention provides a printing module suitable for a three-dimensional forming mechanism for laying powder particles having a particle size of 20-120 μm, and the printing module comprises at least a jet printing and a printing control circuit, Wherein the ink jet print has a spray orifice sheet and a spray print wafer, the spray orifice sheet has a plurality of spray holes, wherein the plurality of spray holes have a pore diameter of 15-20 μm, and the driving voltage of the sprayed wafer is Controlled at 12-15 volts, and the printing control circuit transmits a heating pulse voltage of 1.4-2.0 μs to the printing wafer, the plurality of nozzles eject droplets having a diameter of about 64-68 μm to cover the powder particles at least 2/3 or more surface area.

11, 72‧‧‧ powder particles

12, 71‧‧‧ Construction platform

13‧‧‧Liquid

3‧‧‧Printing 匣

31‧‧‧Printing wafer

32‧‧‧Electrical connection piece

33‧‧‧ orifice sheet

331‧‧‧ orifice

34‧‧‧ axis array

35‧‧‧heater

350‧‧‧ gap

3511-3513, 3511', 3513‧‧‧ heating plate

352, Ain‧‧‧ input

353, Aout‧‧‧ output

354‧‧‧ Conductive layer

355, 355' ‧ ‧ inkjet area

36‧‧‧Ink flow channel

6‧‧‧Print control circuit

73‧‧‧ droplets

R1, R2, R3, R4‧‧‧ resistance

P‧‧‧Power signal

D‧‧‧ data control signal

M‧‧‧ switching components

G‧‧‧ Grounding terminal

PD‧‧‧Printing information signal

MF‧‧‧heat control signal

PF‧‧‧Preheat control signal

P1‧‧‧ preheating pulse voltage

P2‧‧‧heat pulse voltage

T1, t2‧‧‧ length of time

Y‧‧‧ total width

Y1‧‧‧Width

X‧‧‧ length

L‧‧‧ reference axis

The first figure is a schematic view showing the structure of the powder particles to be printed on the microscopic surface.

Second: It is a schematic cross-sectional view of the printing liquid on the powder particles shown in the first figure.

Fig. 3A is a schematic view showing the structure of the ink jet cartridge of the preferred embodiment of the present invention.

Third Figure B: This is a schematic view of the structure after the removal of the orifice sheet in Figure 3A.

Third figure C: It is a schematic structural view of the third figure A after removing a part of the orifice sheet.

Fourth Figure A: This is a schematic diagram of the heater shown in Figure B.

Fourth Figure B: This is a circuit diagram of Figure 4A.

Figure 5: This is a schematic diagram of another heater shown in Figure B.

Figure 6 is a schematic view showing the connection structure between the printing control circuit and the printing chip of the printing module.

FIG. 6B is a waveform diagram of voltage signals of the printing material signal PD, the heating control signal MF, and the preheating control signal PF shown in FIG.

Figure 7 is a schematic cross-sectional view showing the use of the printing module of the present invention to print droplets on powder particles.

Figure 8 is a diagram showing the relationship between the driving voltage of the printed wafer and the ejection speed of the nozzle.

Some exemplary embodiments embodying the features and advantages of the present invention are described in detail in the following description. It is to be understood that the present invention is capable of various modifications in the various aspects of the present invention, and the description and illustration are in the nature of

The printing module of the present invention can be applied to a three-dimensional forming mechanism (not shown), for example, a floor-standing three-dimensional forming mechanism for constructing a 3D solid model, and the three-dimensional forming mechanism is laid on a construction platform 71 with a particle size of 20 a powder particle 72 having a size of 120 μm (as shown in the seventh figure), the printing module comprising at least one printing cartridge 3 (as shown in FIG. 3A) and a printing control circuit 6 (such as the sixth drawing A) Shown).

Please refer to FIG. 3A, which is a schematic structural view of a printing cartridge according to a preferred embodiment of the present invention. The printing cartridge 3 shown in the third figure A is a simplified structural diagram. In the embodiment, the printing cartridge 3 is a long strip structure and includes a printing chip 31 and an electrical connecting sheet 32. The orifice sheet 33 and the heater 35 of the three axis arrays 34 (as shown in FIG. 3B), and the orifice sheet 33 includes a plurality of orifices 331 corresponding to the heaters 35.

Please refer to the third figure B and C, wherein the third figure B is the structural diagram of the third figure A after removing the orifice sheet, and the third figure C is the third figure A after removing part of the orifice sheet. Schematic diagram, as shown, the heaters 35 on the surface of the printing die 31 of the printing cartridge 3 of the present embodiment are arranged in an array of axes 34 extending along the reference axis L, and are relatively referenced. The axis L is laterally or laterally isolated from each other. In addition, the inkjet wafer 31 further has three ink supply channels 36 parallel to the reference axis L, mainly for conveying ink of different colors, and relative to each other with respect to the reference axis L. The vertical direction is divided side by side, thereby providing inks of different colors for the heaters 35 of the corresponding three axis arrays 34, and each axis array 34 can be composed of two rows of the same color ink heaters 35 disposed on both sides of the ink supply flow path 36. And both of them are parallel to the direction of the reference axis L, and the two rows of heaters 35 are disposed on both sides of the ink supply flow path 36 in a staggered manner. Therefore, the print wafer 31 of the present embodiment has two rows of x. 3 colors = 6 rows of heater rows.

Please refer to FIG. 4A, which is a schematic diagram of the heater shown in FIG. As shown, the heater 35 mainly includes a plurality of heating plates 3511-3513, an input end 352, an output end 353, and a conductive layer 354 connected in series with two adjacent heating plates 3511-3512, 3512-3513. In the present embodiment, the heater 35 is preferably formed by three heating plates 3511-3513, but not limited thereto, and a gap 350 is provided between the two adjacent heating plates 3511, 3512 and the heating plates 3512, 3513. Separated from each other, the heating plates 3511-3513 are arranged side by side, and the length X, the width Y1 and the thickness (not shown) of each of the heating plates 3511, 3512, 3513 in this embodiment are substantially equal, that is, The heating plates 3511-3513 may be rectangular resistive layers of the same area and equal volume, and the total width Y of the gap 350 and the plurality of heating plates 3511-3513 is approximately equal to the length X of the heating plates 3511-3513, in other words, the plurality of heating plates 3511 The ink jet region 355 defined by -3513 and the gap 350 therebetween is approximately a positive quadrilateral ink jet region 355 having an area of X x Y.

In addition, the heating plate 3512 in the middle is electrically connected to the heating plates 3511 and 3513 through the conductive layer 354, and the other end of the heating plate 3511 is connected to the input end 352 with respect to the other end connected to the conductive layer 354. The board 3513 is connected to the output end 353 with respect to the other end connected to the conductive layer 354, and the input end 352 and the output end 353 can be the same conductive material as the conductive layer 354. In other words, the heater 35 is electrically connected to the input end 352 and the output end 353 of the heating plates 3511 and 3513 of the two terminals, respectively, and between the three heating plates 3511-3513. The conductive layers 354 are also electrically connected to each other in series.

Please refer to FIG. 4B and cooperate with FIG. 4A. FIG. 4B is a circuit diagram of FIG. A. The circuit of the heater 35 includes a plurality of resistors R1, R2 and R3 connected in series, which respectively correspond to the first The heating plates 3511, 3512, and 3513 in FIG. A, and the input terminal Ain and the output terminal Aout correspond to the input terminal 352 and the output terminal 353 in the fourth FIG. As shown in the fourth figure B, the resistor R1 at the terminal of the series resistors R1-R3 is connected to the input terminal Ain and receives the power signal P, for example, the driving voltage, and the resistor R3 of the other terminal of the resistor R1-R3 connected in series. Then, it can be directly grounded, or the resistor R3 is connected to the drain of the switching element M through the output terminal Aout, and the switching element M receives a data control signal D through the gate and is sourced. It is connected to the ground terminal G, and controls the conduction of the heating circuit by receiving the data control signal D by the switching element M. In some embodiments, the switching element M can be a transistor, such as an NMOS device, but is not limited thereto.

When the heater 35 is to heat a liquid, such as ink (not shown), to perform printing, the print control circuit 6 will transmit a data control signal D to control the switching element M to be turned on, while the power signal P will be driven by the heater 35. The input terminal Ain is input, so that the temperature of the heating plates 3511, 3512 and 3513 of the heater 35 can be raised, thereby heating the liquid to generate micro-thermal bubbles, so that the liquid micro-thermal bubbles are ejected from the ink-jet region 355 to the powder particles. 72 to complete the printing action.

Please refer to the fifth figure, which is a schematic diagram of another heater shown in FIG. As shown, the heater 35 also includes a plurality of heating plates 3511', 3512, 3513', The input end 352, the output end 353, and the conductive layer 354 of two adjacent heating plates 3511'-3512, 3512-3513' are connected in series, and the number of the plurality of heating plates of the heater 35 is preferably three, and in this embodiment The arrangement of the heating plates 3511', 3512, 3513' and their relationship with the input end 352, the output end 353 and the conductive layer 354 are the same as those of the preferred embodiment shown in FIG. A, and will not be described again. In this embodiment, the widths Y1 and thicknesses of the three heating plates 3511', 3512, 3513' are substantially equal, and only one of the two heating plates 3511', 3513' connected to the input end 352 and the output end 353 respectively faces outward. The length of the side is smaller than the length X of the heating plate 3512 located in the middle, that is, the heating plate 3512 is still a rectangular resistance layer, but the heating plates 3511' and 3513' are substantially two corresponding ladder resistance layers, at this time and input. The two heating plates 3511', 3513' electrically connected to the end 352 and the output end 353 have an area substantially smaller than the area of the heating plate 3512, and the ink-jet area 355 defined by the heating plates 3511', 3512, 3513' and the gap 350 are defined. 'There is roughly a regular octagon.

Since the heating plate 3512 located in the middle accounts for most of the resistance value of the heater 35 and is relatively larger than the resistance values of the heating plates 3511' and 3513' of the two terminals, it should be understood that when the heater 35 is heated, the highest The temperature zone can be concentrated in the central range of the ink-jetting zone 355' to avoid hot spot shifting of the three heating plates 3511', 2352, 3513' due to delayed heating, and to control the liquid micro-thermal bubble. It is relatively easily grown by the center of the heater 35 and ejected onto the powder particles 72.

Please refer to the sixth figure A and B, wherein the sixth figure A is a schematic diagram of the connection structure between the printing control circuit and the printing chip of the printing module, and the sixth drawing B is the printing material signal PD and the heating control signal MF. The voltage signal waveform diagram of the preheating control signal PF is as shown in the figure. When the printing module is to perform the printing operation, the printing control circuit 6 transmits the printing data signal PD, the heating control signal MF and the pre Thermal control signal PF to print wafer 31, the heater 35 is controlled to be heated or preheated, wherein the preheating control signal PF and the heating control signal MF respectively have a preheating pulse voltage P1 and a heating pulse voltage P2, and the heater 35 is controlled by the preheating pulse voltage P1. A part of the ink and the printing paste 3 are preheated, and then a part of the liquid is heated by the heating pulse voltage P2 to generate bubbles to spray the liquid onto the corresponding powder particles 72.

Referring to FIG. 6 again, when the printing material signal PD is a high potential signal, the heater 35 is controlled by the heating control signal MF to control the heating of the heater 35. Conversely, when the printing material signal PD is a low potential signal. When the heater is controlled by the preheating control signal PF, the heater 35 is preheated, that is, when the printing module performs the printing operation, if the printing data is printed, the printing data signal PD is At a high potential, the printing module heats the partial liquid by the heater 35 by heating the control signal MF to generate bubbles, thereby pushing the droplets out of the orifice 331 of the orifice 33, and vice versa if no data is printed. When the printing data signal PD is at a low potential, the printing module controls the heater 35 to preheat some of the liquid and the printing cartridge 3 by the printing material signal PD.

The heating control signal MF and the preheating control signal PF are continuously transmitted as the printing module performs the printing operation, wherein the time length t1 of the preheating pulse voltage P1 and the time length t2 of the heating pulse voltage P2 are different according to the different spraying The module model is different. The voltages of the control signals of the printing module, that is, the printing data signal PD, the heating control signal MF and the preheating control signal PF may vary depending on the type of the printing module.

Please refer to the third figure AC, the fourth figure AB, the fifth figure, the sixth figure AB and the eighth figure. The apertures 331 included in the orifice plate 33 of the printing sputum 3 of the present invention may have a hole diameter of 15- 20 μm, when the printing module is to perform the printing operation, the driving voltage of the printing control circuit 6 to the printing chip 31 can be 12-15 volts (as shown in the eighth figure), And the printing control circuit 6 can transmit a heating pulse voltage of 1.4-2.0 μs to the printing wafer 31, so that the plurality of nozzle holes 331 can eject droplets 73 having a diameter of about 64-68 μm at a discharge speed of 14-16 m/s. In this way, the ejected liquid droplets 73 can cover the surface area of the powder particles 72 having a particle size of 20-120 μm laid on the construction platform 71 by the three-dimensional forming mechanism at least 2/3 or more.

In the embodiment of the present invention, the particle size of the powder particles 72 is preferably 70 μm, so that the plurality of nozzle holes 331 are ejected at a discharge speed of 14-16 m/s, and the droplets 73 having a diameter of 64-68 μm can almost completely cover the powder. The surface area of the particles 72 (as shown in the seventh figure), the printing module of the present invention only needs to perform one printing on the same powder particle 72, which can achieve rapid printing, single printing, good printing quality and prolonged printing. Spray 匣 3 life and other effects.

In summary, the printing module applicable to the three-dimensional forming mechanism of the present invention is that the aperture of the plurality of nozzles included in the orifice sheet of the printing cartridge is 15-20 μm, and the driving voltage of the printing chip is 12-15 volts, and the printing control circuit transmits a heating pulse voltage of 1.4-2.0 μs to the printing wafer, so that a plurality of nozzles can eject droplets having a diameter of about 64-68 μm to cover a particle size of 20-120 μm. The surface area of the powder particles makes the printing module of the present invention only need to be printed on the same powder particle once, which can achieve fast printing, single printing to achieve good printing quality and prolong the life of the printing enamel.

This case has been modified by people who are familiar with the technology, but it is not intended to be protected by the scope of the patent application.

<AlEx><AlEx>

71‧‧‧Building a platform

72‧‧‧ powder particles

73‧‧‧ droplets

Claims (5)

A printing module is suitable for a three-dimensional forming mechanism for laying 20-120 μm powder particles, the printing module comprises at least one printing cartridge and a printing control circuit, wherein the printing cartridge has a orifice sheet and a printing chip, the orifice sheet having a plurality of orifices, wherein the plurality of orifices have a pore diameter of 15-20 μm, and when the driving voltage of the printing chip is controlled at 12-15 volts And the printing control circuit transmits a heating pulse voltage of 1.4-2.0 μs to the printing wafer, the plurality of nozzles eject droplets having a diameter of about 64-68 μm to cover at least 2/3 of the surface area of the powder particles. Wherein the powder particle size is preferably 70 μm. The printing module of claim 1, wherein the printing cartridge further comprises a plurality of heaters, each heater comprises a plurality of heating plates, and the plurality of heating plates are separated and arranged in parallel A conductive layer is electrically connected to each other in series to form an ink-jet region, and the heating plates of the two terminals are electrically connected to an input end and an output end, respectively. The printing module of claim 2, wherein the ink ejection region is substantially a regular quadrilateral, and the plurality of heating plates are substantially rectangular in area. The printing module of claim 2, wherein the ink ejection area is substantially a regular octagon, and the area of the heating plate opposite to the two terminals electrically connected to the input end and the output end is substantially The upper system is smaller than the remaining area of the heating plate to avoid the hot spot offset of the heater. The printing module according to claim 1, wherein the ejection speed of the droplet is 14-16 m/s when the driving voltage of the printing chip is 12-15 volts.