Adaptive doctor for light-cured 3D printing devices

Abstract

The utility model provides an adaptive scraper of photocuring 3D printing equipment application relates to 3D printing auxiliary equipment technical field, including scraper body, electric push rod, range sensor, still have detection circuit, comparison control circuit, electric push rod cylinder body is installed in scraper frame's installation groove, electric push rod movable column is installed on scraper body upper end, and scraper front outer end has fixed frame, and range sensor is installed in fixed frame front, detection circuit, comparison control circuit are installed in electric control box and are connected with electricity, the initial stage of this new type control system control motor reduction mechanism drive scraper rotation, range sensor can automatically detect the interval of scraper and resin in the upper end of groove, when the interval is greater than or less than threshold value, comparison control circuit can automatically adjust low or adjust high scraper height through electric push rod, so that the lower end of scraper just contacts the surface of resin, prevents the interval resin interval of scraper too big or too small, subsequent influence secondary photocuring 3D printing equipment printing product quality problem.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing auxiliary equipment technology, and in particular to an adaptive scraper for use in photopolymer 3D printing equipment. Background Technology

[0002] A photopolymer 3D printer is a computer-aided device that uses photopolymerization technology to create three-dimensional models by curing liquid photosensitive resin in layers. Compared to fused deposition modeling (FDM), this device offers higher printing precision and surface smoothness, achieving a texture-free finish and producing more robust finished products. This technology has been widely applied in fields such as figurine making, industrial design, dental care, custom jewelry, and anime model making. The workflow of a photopolymer 3D printer mainly includes the following steps: (1) Data processing and modeling: After creating the model using CAD software, it needs to be exported as an STL format file, and the model is decomposed into thin layer data (the layer thickness is usually 10-100 micrometers) using slicing software (such as Formlabs PreForm or ChiTuBox). (2) Equipment preparation: After powering on, the laser needs to be calibrated, the liquid level height needs to be checked, and the resin tank needs to be free of impurities. After the platform moves to the initial position, the software enters the feeding state. (3) Layer-by-layer curing: The ultraviolet laser irradiates from the bottom of the resin tank and draws the model outline layer by layer. After each layer is cured, the platform rises and injects new resin to continue printing the next layer. (4) Peeling and post-processing: The cured layer is removed from the platform by tilting or vibration, and then soaked in isopropanol for 5-10 minutes to remove the uncured resin. The printed model is cured under ultraviolet light for 10-30 minutes to enhance its strength, and finally the printed model is obtained. In actual operation, after the resin is injected into the resin tank, the photosensitive resin is cured layer by layer by laser during the printing process. A scraper (fixed at the bottom of the scraper holder) is needed to evenly spread the liquid resin to the set thickness to ensure that the material thickness is consistent when each layer is cured, avoiding poor interlayer bonding or surface roughness due to uneven resin flow. The scraper can also press the resin to the micron level through mechanical structure. Combined with laser dot exposure technology, it can achieve high-precision detail engraving. For example, circuit board prototype design requires a line width accuracy of 0.5 microns. The resin surface smoothed by the scraper is more conducive to precise laser exposure. Finally, continuous scraper operation can reduce the number of laser exposures. Combined with high-speed pump air knife to recover waste, it shortens the printing time per layer. For example, the MAASS Shimmy prints at a speed of 6mm / h. The continuous smoothing operation of the scraper improves the overall efficiency.

[0003] The squeegee of a photopolymer 3D printer typically moves via a moving platform under the control of a control system. This movement is driven by a vertical (squeegee up / down drive mechanism, usually an electric actuator; the squeegee moves downwards when the control system's squeegee up / down drive mechanism outputs positive and negative power, and upwards when it outputs negative and positive power) and a rotational (squeegee rotation drive mechanism, usually a motor reduction mechanism; specifically, the squeegee will rotate and level the resin 8-9 seconds after being adjusted to its vertical position; the exact timing can be adjusted through control system programming) motion. After each resin injection and leveling process, before the next injection, the control system first controls the moving platform to raise the squeegee a certain height, then controls the squeegee to rotate circumferentially to level the resin. In practice, the control system's program controls the upward or circumferential rotation of the scraper via the moving platform. Similarly, the time it takes for the resin injection device to inject resin into the resin tank (longer times mean more resin) is also controlled by the program. However, this presents a problem: if the control program deviates from the scraper's movement and resin injection time for various reasons, or if the resin's fluidity varies (generally, resin with higher viscosity flows more slowly), the scraper may not effectively smooth the resin's surface, affecting the quality of subsequent printed products. For example, resin with higher fluidity might be injected deeper into the resin tank, or resin with lower fluidity might be injected shallower, or the scraper's lower end might be too deep within the resin or not contacting the resin's surface at all, all impacting the quality of subsequent printed products. Therefore, providing a scraper that automatically adjusts its height based on the resin's surface height is particularly necessary. Utility Model Content

[0004] To overcome the shortcomings of existing photopolymer 3D printer scrapers, which are limited by their own and auxiliary system functions and are described in the background art, this utility model provides an adaptive scraper that, under the combined action of related circuits and mechanisms, can automatically detect the distance between the scraper and the upper end of the resin in the resin tank during the initial stage of each scraper rotation driven by the motor reduction mechanism controlled by the control system. When the distance is greater than or less than a threshold, the height of the scraper can be automatically adjusted to either lower or higher, so that the lower end of the scraper just contacts the surface of the resin. This prevents the scraper from being too large or too small in distance from the resin, which would affect the quality of the printed product.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] The adaptive scraper used in photopolymer 3D printing equipment includes a scraper body, an electric push rod, a distance sensor, and also has a detection circuit and a comparison control circuit. The scraper body and the lower end of the scraper holder are separate structures. The lower end of the scraper holder has a mounting groove, and the cylinder of the electric push rod is fixedly installed in the mounting groove of the scraper holder. The lower end of the movable column of the electric push rod is fixedly installed on the upper end of the scraper body. A fixing frame is fixedly installed on the front outer end of the scraper, and the upper end of the housing of the distance sensor is fixedly installed on the front outer end of the fixing frame. The detection circuit and the comparison control circuit are installed in the electrical control box. The power output terminal of the detection circuit is electrically connected to the power input terminal of the distance sensor and the comparison control circuit. The signal output terminal of the distance sensor is electrically connected to the signal input terminal of the comparison control circuit. The power output terminal of the comparison control circuit is electrically connected to the power input terminal of the electric push rod. The positive terminal of the drive power output terminal of the scraper up and down drive mechanism of the photopolymer 3D printing equipment control system is electrically connected to the signal input terminal of the comparison control circuit.

[0007] Furthermore, the probe of the ranging sensor is located at the lower end, with the lower part of the probe positioned forward of the outer front end of the scraper.

[0008] Furthermore, when the movable column of the electric push rod is at its upper stop point, the upper end of the scraper and the lower end of the scraper holder are in contact.

[0009] Furthermore, the detection circuit includes a diode and a time-delay relay module that are electrically connected. The positive trigger terminal of the time-delay relay module is connected to the negative terminal of the diode, and the negative power input terminal and the negative trigger terminal of the time-delay relay module are connected.

[0010] Furthermore, the comparison control circuit includes voltage comparison modules and relays that are electrically connected. The positive power input terminals of the two voltage comparison modules and the positive control power input terminals of the two relays are connected. The negative power input terminal and negative signal input terminal of the voltage comparison modules are connected to the negative power input terminal and negative control power input terminal of the two relays. The power output sources of the two voltage comparison modules and the positive power input terminals of the two relays are respectively connected. The positive signal input terminals of the two voltage comparison modules are connected.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: Under the joint action of related circuits and mechanisms, in the initial stage of the control system of each photopolymerization 3D printing equipment controlling the motor reduction mechanism to drive the scraper to rotate, the distance sensor can automatically detect the distance between the scraper and the upper end of the resin in the resin tank. When the distance is greater than or less than the threshold, the comparison control circuit can automatically adjust the height of the scraper by electric push rod, so that the lower end of the scraper just contacts the surface of the resin, thus preventing the problem of the scraper spacing from the resin being too large or too small, which would affect the quality of the printed products of the subsequent photopolymerization 3D printing equipment. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] Figure 2 This is a partial structural schematic diagram of the present invention.

[0015] Figure 3 This is the circuit diagram of this utility model. Detailed Implementation

[0016] Figure 1 , 2 As shown in Figure 3, the adaptive scraper used in the photopolymer 3D printing equipment includes a scraper body 1, a power module T1, an electric push rod Y, and a distance sensor T4. It also has a detection circuit 2 and a comparison control circuit 3. The lower ends of the scraper body 1 and the scraper holder 101 are of a split structure. There are at least two sets of electric push rods Y. There is a recessed mounting groove 102 on both sides of the lower middle part of the scraper holder 101. The cylinders of the two sets of electric push rods Y are vertically distributed and fixedly installed in the two mounting grooves 102 on both sides of the scraper holder 101. The lower ends of the movable columns of the two sets of electric push rods Y are fixedly installed on the upper left and right middle parts of the upper end of the scraper body 1. A "˥"-shaped fixing bracket 103 is fixedly installed on the upper middle part of the front outer end of the scraper body 1. The upper end of the housing of the distance sensor T4 is fixedly installed on the middle part of the front outer end of the fixing bracket 103. The power module T1, the detection circuit 2, and the comparison control circuit 3 are installed on the circuit board inside the electrical control box 4 of the photopolymer 3D printing equipment.

[0017] Figure 1 , 2As shown in Figure 3, the probe of the ranging sensor T4 is located at the lower end, with the lower part of the probe positioned forward of the outer front end of the scraper body 1. When the movable column of the electric push rod Y is at its upper stop, the upper end of the scraper body 1 contacts the lower end of the scraper holder 101. The detection circuit includes a diode D1 and a time-delay relay module T3 connected via circuit board wiring. The positive trigger terminal (pin 3) of the time-delay relay module T3 is connected to the negative terminal of the diode D1, and the negative power input terminal (pin 2) and the negative trigger terminal (pin 4) of the time-delay relay module T3 are connected. The comparison control circuit includes voltage comparison modules T5 and T6 and relays J and J1 connected via circuit board wiring. The positive power input pin 1 of the two voltage comparison modules T5 and T6 is connected to the positive control power input pin of the two relays J and J1. The negative power input pin 2 and negative signal input pin 4 of the voltage comparison modules T5 and T6 are connected to the negative power input pin and negative control power input pin of the two relays J and J1. The power output pin 5 of the two voltage comparison modules T5 and T6 is connected to the positive power input pin of the two relays J and J1 respectively. The positive signal input pin 3 of the two voltage comparison modules T5 and T6 is connected.

[0018] Figure 1 , 2 As shown in Figure 3, the power input terminals 1 and 2 of the power module T1 are connected to the two poles of the 220V AC power supply via wires. The power output terminals 3 and 4 of the power module T1 are connected to the power input terminals of the detection circuit and the time delay relay module T3 via wires. The power output terminals of the detection circuit and the time delay relay module T3 via wires are connected to the power input terminals 1 and 2 of the distance sensor T4, and the power input terminals of the voltage comparison modules T5 and T6 of the comparison control circuit via wires. The signal output terminal 3 of the distance sensor T4 is connected to the signal input terminals of the voltage comparison modules T5 and T6 of the comparison control circuit via wires. The two normally open contacts of the power output relays J and J1 of the comparison control circuit and the positive and negative and negative positive power input terminals of the two sets of electric push rods Y are connected via wires. The positive terminal L of the scraper up and down drive mechanism of the photopolymerization 3D printing equipment control system T2 is connected to the positive terminal of the diode VD of the comparison control circuit via wires.

[0019] Figure 1 , 2As shown in Figure 3, after the AC 220V power supply enters the power input terminal of the power module T1, the power output terminal of the power module T1 outputs DC 12V power supply, which enters the power input terminal of the detection circuit. The scraper body 1 of the photopolymer 3D printer, under the action of the control system T2, moves up and down (driven by the scraper up and down drive mechanism, which is generally an electric push rod; when the scraper up and down drive mechanism of the control system drives the power output terminal to output positive and negative power, the scraper moves down; when the scraper up and down drive mechanism of the control system drives the power output terminal to output negative and positive power, the scraper moves up) and rotates (driven by the scraper rotation drive mechanism, which is generally a motor reduction mechanism) to level the resin in the resin tank. After each resin tank is filled and leveled, before the next resin injection, the control system T2 will first control the moving platform to move the scraper body up a certain height, and then control the scraper body to rotate in the circumferential direction to level the resin (the above are existing mature technologies, which will not be described in detail in this application). In this application, after the positive terminal L of the power output terminal of the scraper up and down drive mechanism of the control system T2 enters the positive signal input terminal 3 of the time delay relay module T3, the time delay relay module T3 will output power for a certain period of time (for example, output power for 4 seconds at 4-second intervals) to the power input terminal of the ranging sensor T4 and the comparison control circuit under the action of its internal circuit, and the ranging sensor T4 and the comparison control circuit will be powered on and work. When the gap between the lower end of the scraper body 1 and the resin in the resin tank is appropriate and not too large (when the control system makes the drive mechanism control the scraper body 1 to move down or up with an appropriate distance between the resin; for example, when the lower end of the probe of the distance sensor T4 is 5 mm away from the resin, the lower part of the scraper body is just 1 mm below the upper end of the resin), the voltage signal input from pin 3 of the distance sensor T4 to pin 3 of the voltage comparator T5 is relatively low (in actual cases, the smaller the gap between the lower probe of the distance sensor T4 and the resin, the lower the voltage signal output from pin 3, and vice versa). This voltage signal is less than the internal threshold voltage of the voltage comparator T5, so pin 5 of the distance sensor T4 does not output power to the power input terminal of the relay J. The relay J will not be energized and will not be engaged. Therefore, the positive and negative power input terminals of the electric push rod Y will not be energized, and the scraper body 1 will not descend in height. The scraper body will then be at an appropriate height to scrape the resin.When the resin gap between the lower end of the scraper body 1 and the resin tank is too large (for example, the resin gap between the lower end of the probe of the ranging sensor T4 and the resin is more than 5.5 mm), the voltage signal input from pin 3 of the ranging sensor T4 to pin 3 of the voltage comparator T5 is relatively high. This voltage signal is greater than the internal threshold voltage of the voltage comparator T5. The power output from pin 5 of the ranging sensor T4 enters the power input terminal of the relay J. The relay J will be energized and its control power input terminal and normally open contact terminal will close. Then the positive and negative power input terminals of the electric push rod Y will be energized, and its movable column will drive the scraper body 1 to descend. When the height drops to 5 mm between the lower end of the probe of the ranging sensor T4 and the resin, pin 3 of the voltage comparator T5 stops outputting power. Then the electric push rod Y will no longer drive the scraper body 1 to descend. The scraper body is at a suitable height and then scrapes the resin.

[0020] Figure 1 , 2 As shown in Figure 3. When the lower end of the scraper body 1 is appropriately spaced from the resin in the resin tank (when the control system makes the drive mechanism control the scraper body 1 to move downward or upward at an appropriate distance from the resin; for example, when the lower end of the probe of the distance sensor T4 is 5 mm from the resin, the lower part of the scraper body is just 1 mm below the upper end of the resin), the voltage signal input from pin 3 of the distance sensor T4 to pin 3 of the voltage comparator T6 is relatively high. This voltage signal is greater than the internal threshold voltage of the voltage comparator T5. Pin 5 of the voltage comparator T5 does not output power to the power input terminal of the relay J1. The relay J1 will not be energized and will not be engaged. Therefore, the negative and positive power input terminals of the electric push rod Y will not be energized, and the scraper body 1 will not rise in height. The scraper body will then be at an appropriate height to scrape the resin. When the resin gap between the lower end of the scraper body 1 and the resin in the resin tank is too small (for example, the lower end of the probe of the ranging sensor T4 is 4.5 mm from the resin), the voltage signal input from pin 3 of the ranging sensor T4 to pin 3 of the voltage comparator T5 is relatively low. This voltage signal is lower than the internal threshold voltage of the voltage comparator T6. The power output from pin 5 of the voltage comparator T6 enters the power input terminal of the relay J1. The relay J1 will be energized and its control power input terminal and normally open contact terminal will close. Then, the positive and negative power input terminals of the electric push rod Y will be energized, and its movable column will drive the scraper body 1 to rise. When the height rises to 5 mm from the resin gap between the lower end of the probe of the ranging sensor T4, pin 3 of the voltage comparator T6 stops outputting power. Then, the electric push rod Y will no longer drive the scraper body 1 to rise. The scraper body is at a suitable height and continues to scrape the resin.

[0021] Figure 1 , 2As shown in Figure 3, through the above, in the initial stage of the control system of the photopolymer 3D printing equipment, the control motor reduction mechanism drives the scraper to rotate. The distance sensor can automatically detect the distance between the scraper and the upper end of the resin in the resin tank. When the distance is greater than or less than the threshold, the comparison control circuit can automatically adjust the height of the scraper by the electric push rod, so that the lower end of the scraper just contacts the surface of the resin. This prevents the problem of the scraper being too large or too small from the resin, which would affect the quality of the printed products of the photopolymer 3D printing equipment. Figure 3 In the diagram, power module T1 is a finished product of AC 220V to DC 12V power module; relays J and J1 are DC 12V models; electric actuator Y is a finished product of YS-L35 miniature reciprocating electric telescopic actuator; diode D1 is model 1N4007 (unidirectional conduction, reverse cutoff function); and time delay relay module T3 is from the brand Your. Cee's one-way time-delay relay module has two power input terminals (pins 1 and 2), two trigger signal input terminals (pins 3 and 4), four setting buttons, one control power input terminal (pin 7, connected to pin 1), one normally open power output terminal (pin 5), and one normally closed contact terminal (floating). After power-on, adjusting the four setting buttons allows setting the time interval between each power output terminal receiving a trigger signal from the two trigger signal input terminals, as well as the total power output time. During operation, power is output from the normally open power output terminal after each trigger signal input from the two trigger signal input terminals. Voltage comparators T5 and T6 are finished voltage comparators of model JY-VC01, which have two power input terminals (pins 1 and 2) and two control signal input terminals (pins 3 and 4). The circuit board has a high-level output pin 5. Depending on the required selection, it can set the voltage of the two control signal input terminals to be higher or lower than the set threshold voltage. The high-level output pin 5 outputs power. There is an adjustable resistor for setting the threshold voltage on its circuit board. Before production, the smaller the resistance value of the adjustable resistor is, the lower the subsequent input voltage will be, and the higher the resistance value of the adjustable resistor will be, the higher the subsequent input voltage will be. The ranging sensor T4 is a finished laser ranging sensor product of model XKC-KL200. It has two power input terminals, pins 1 and 2, and one signal output terminal, pin 3. The farther the distance between the ranging sensor's probe and the object, the higher the voltage signal output by pin 3, and vice versa.

[0022] Those skilled in the art should understand that although this specification describes embodiments, the embodiments do not necessarily contain only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. Therefore, the scope of protection of this application is defined by the claims.

Claims

1. An adaptive scraper used in photopolymer 3D printing equipment, comprising a scraper body, an electric push rod, and a distance sensor, characterized in that, It also features a detection circuit and a comparison control circuit. The scraper body and scraper holder are separate structures. The lower end of the scraper holder has a mounting groove, and the cylinder of the electric push rod is fixedly installed in the mounting groove of the scraper holder. The lower end of the movable column of the electric push rod is fixedly installed on the upper end of the scraper body. A fixing frame is fixedly installed on the front outer end of the scraper, and the upper end of the housing of the distance sensor is fixedly installed on the front outer end of the fixing frame. The detection circuit and the comparison control circuit are installed in the electrical control box. The power output terminal of the detection circuit is electrically connected to the power input terminal of the distance sensor and the comparison control circuit. The signal output terminal of the distance sensor is electrically connected to the signal input terminal of the comparison control circuit. The power output terminal of the comparison control circuit is electrically connected to the power input terminal of the electric push rod. The positive terminal of the scraper up and down drive mechanism drive power output terminal of the photopolymerization 3D printing equipment control system is electrically connected to the signal input terminal of the comparison control circuit.

2. The adaptive scraper used in the photopolymerization 3D printing equipment according to claim 1, characterized in that, The probe of the ranging sensor is located at the lower end, with the lower part of the probe positioned forward of the outer front end of the scraper.

3. The adaptive scraper used in the photopolymerization 3D printing equipment according to claim 1, characterized in that, When the movable column of the electric push rod is at its top dead center, the upper end of the scraper and the lower end of the scraper holder are in contact.

4. The adaptive scraper used in the photopolymerization 3D printing equipment according to claim 1, characterized in that, The detection circuit includes an electrically connected diode and a time-delay relay module. The positive trigger terminal of the time-delay relay module is connected to the negative terminal of the diode, and the negative power input terminal and the negative trigger terminal of the time-delay relay module are connected.

5. The adaptive scraper used in the photopolymerization 3D printing equipment according to claim 1, characterized in that, The comparison control circuit includes electrically connected voltage comparison modules and relays. The positive power input terminals of the two voltage comparison modules and the positive control power input terminals of the two relays are connected. The negative power input terminal and negative signal input terminal of the voltage comparison modules are connected to the negative power input terminal and negative control power input terminal of the two relays. The power output source of the two voltage comparison modules and the positive power input terminal of the two relays are respectively connected. The positive signal input terminal of the two voltage comparison modules is connected.

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