TWI592288B - A rapid prototyping equipment and a method for controlling thereof - Google Patents

Description

Rapid prototyping device and control method thereof

The invention relates to the technical field of rapid prototyping devices, in particular to a rapid prototyping device and a control method thereof.

Three-dimensional printing, also known as 3D printing, is a kind of rapid prototyping technology. It is based on a digital model file. It is made of an adhesive material such as powder metal or plastic. Technology. Three-dimensional printing has begun to be widely used in industrial design, mold manufacturing and other fields.

The 3D printer consists of control components, mechanical components, print heads, consumables, and media. In addition to the cooling fan, the three-dimensional printer generally has four main motors, which are responsible for the movement and feeding of the nozzles in the X-axis, Y-axis, and Z-axis directions, respectively. The accuracy of the motor directly determines the printing result. However, the current three-dimensional printer mainly adopts the method of open-loop control. When the motor loses synchronization and overshoot, it may lead to the printing of defective products, thereby reducing the yield rate and causing waste of materials and time.

In view of this, embodiments of the present invention provide a rapid prototyping apparatus and a control method thereof, which can achieve precise control of a motor to improve the accuracy of three-dimensional printing.

A rapid prototyping device according to an embodiment of the invention comprises a motor, a print head, a work table, at least one first inductive element, a second inductive element, and a control component. At least one first inductive element is disposed on the rotor of the motor. The second sensing element is configured to generate an inductive signal by the action of the at least one first sensing element when the rotor rotates. The control element is configured to receive the sensing signal and generate a control signal to control the operation of the motor.

A method for controlling a rapid prototyping apparatus according to an embodiment of the present invention includes: providing at least one first inductive element on a rotor of the motor; and generating an inductive signal by the second inductive element under the action of the at least one first inductive element when the rotor rotates And receiving the sensing signal and generating a control signal that has controlled the operation of the motor.

According to the technical solution of the present invention, the displacement of the printing head or the table is sensed by the rotation of the motor rotor in the induction rapid prototyping device, and the motor is controlled accordingly, so that the movement of the printing head or the table can be accurately controlled, and the movement can be improved. The accuracy of 3D printing.

1‧‧‧Rack

2‧‧‧Base

3‧‧‧X-axis mobile system

4‧‧‧Y-axis mobile system

5‧‧‧Z-axis mobile system

6‧‧‧Printing device

7‧‧‧Workbench

8‧‧‧ Controller

9‧‧‧Information埠

10‧‧‧埠 converter

11‧‧‧Power supply

12‧‧‧Power Stabilizer

13‧‧‧Regulator

31‧‧‧Motor

32‧‧‧First sensing element

33‧‧‧Second sensing element

34‧‧‧Control components

36‧‧•A/D conversion unit

37‧‧‧counting unit

38‧‧‧Control signal generation unit

50‧‧‧Motor housing

51‧‧‧Motor rotor

52‧‧‧First sensing element

53‧‧‧Second sensing element

81‧‧‧Active shaft

82‧‧‧Passive axis

83‧‧‧ Reverse shaft

S41, S42‧‧‧ steps

R‧‧‧direction of rotation

The following drawings are only a few examples of the technical solutions of the present invention, and the present invention is not limited to the features shown in the drawings. In the following figures, like reference numerals indicate similar elements. FIG. 1 is a schematic view showing the structure of a rapid prototyping device.

2 is a block diagram showing a system of a rapid prototyping apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a control mechanism of a rapid prototyping apparatus according to an embodiment of the present invention.

FIG. 4 is a flow chart showing a control method of a rapid prototyping apparatus according to an embodiment of the present invention.

Figure 5a, Figure 5b, Figure 5c, and Figure 5d show the present invention in one implementation. A schematic diagram of an inductive component used in a control mechanism of a rapid prototyping device.

Figure 6 is a schematic view showing a control mechanism of a rapid prototyping apparatus according to another embodiment of the present invention.

Figure 7 is a block diagram showing the structure of a control signal generating device of a rapid prototyping apparatus according to an embodiment of the present invention.

Figure 8a is a schematic structural view of a forward motion control device of a rapid prototyping apparatus according to an embodiment of the present invention.

Figure 8b is a schematic view showing the structure of a reverse motion control device of a rapid prototyping apparatus according to an embodiment of the present invention.

For the sake of brevity and clarity of description, the aspects of the present invention are set forth below by describing several representative embodiments. Numerous details in the examples are only used to assist in understanding the aspects of the invention. However, it is obvious that the technical solution of the present invention can be implemented without being limited to these details. In order to avoid unnecessarily obscuring aspects of the present invention, some embodiments are not described in detail, but only the framework is given. Hereinafter, "including" means "including but not limited to", and "according to" means "at least according to ..., but not limited to only according to...". When the number of one component is not specifically indicated below, it means that the component may be one or more, or may be understood as at least one.

Figure 1 is a schematic view showing the structure of a rapid prototyping apparatus. The rapid prototyping apparatus comprises a frame 1, a base 2, an X-axis moving system 3, a Y-axis moving system 4, a Z-axis moving system 5, a printing device 6, a table 7, a controller (not shown), and a power supply (not shown). Out).

The printing device 6 includes a printing head, a connection mechanism, a feeding mechanism, and the like. X-axis shift The moving system 3, the Y-axis moving system 4 and the Z-axis moving system 5 are respectively used for controlling the printing device and the movement of the table, so that the printing device and the table are relatively moved, so that the printing head supplies the materials supplied by the feeding mechanism according to the column. The printed material is printed on the workbench 7 to complete the three-dimensional printing. The X-axis moving system 3, the Y-axis moving system 4, and the Z-axis moving system respectively include a motor, a moving guide, a gear, a gear belt, and the like. In the example of FIG. 1, the X-axis moving system 3 and the Z-axis moving system 5 are disposed on the frame 1 for controlling the movement of the printing device 6 in the X-axis direction and the Z-axis direction, respectively, and the Y-axis moving system 4 It is disposed on the base 2 for controlling the movement of the table 7 in the Y-axis direction. There are also some rapid prototyping devices that use the X-axis movement system and the Y-axis movement system to control the movement of the printing device along the X-axis and the Y-axis respectively. The Z-axis movement system controls the movement of the table along the Z-axis. The structure will also be the same as Figure 1. There are some differences shown.

A controller (not shown) and a power source (not shown) are generally disposed on the chassis 1 or the base 2. The controller is configured to control the motor of each mobile system and the motor operation of the feeding mechanism according to the set printing data. The controller can be implemented in hardware by specialized hardware or executing machine readable instructions. For example, the controller can be a specially designed permanent circuit or logic device (such as a dedicated processor, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC). The control operations used to perform the setup may also include programmable logic devices or circuits (such as general purpose processors, microcontrollers, or other programmable processors) that are temporarily configured by the software to perform the set control operations. The power supply is used to power each motor and controller.

2 is a block diagram showing a system of a rapid prototyping apparatus according to an embodiment of the present invention. As shown in Figure 2, the rapid prototyping device can include a controller 8, X-axis shift The moving system 3, the Y-axis moving system 4, the Z-axis moving system 5, the printing device 6, and the table 7.

The X-axis movement system 3, the Y-axis movement system 4, and the Z-axis movement system 5 respectively include a motor driver, a motor, and an induction device. The motor driver receives the control signal of the controller 8 and drives the motor to operate according to the control signal. The sensing device senses the operation of the motor and provides an inductive signal to the controller 8. Each mobile system may further include a transmission system, an end stop, etc., and will not be described herein.

The controller 8 is configured to generate control signals of each mobile system according to the set printing data and the sensing signals provided by the sensing devices of the mobile systems, and provide the control signals to the motor drivers of the mobile systems for controlling the mobile systems. The operation of the motor. The controller 8 can be implemented by specially designed permanent circuits or logic devices (such as a dedicated processor such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC)), or can be temporarily configured by software. A programming logic device or circuit (such as a general purpose processor, microcontroller, or other programmable processor).

The controller 8 is further used to control the feeding device and the electric heating nozzle in the printing device 6. The motor driver of the feeding device (e.g., the extrusion device) of the printing device 6 controls the operation of the motor according to the control signal provided by the controller 8, thereby realizing the extrusion of the raw material. The controller 8 is further used to control the heating of the hot bed on the table 7.

The rapid prototyping device provides at least one data 埠9, and the controller 8 obtains the printed data through the data 埠9. The data 埠9 can be a card slot that can receive the memory card insertion. The memory card can be flash memory in various formats, such as an MMC card, an SD card, a mini-SD card, a micro-SD card, a memory stick, an xD image card, and the like. The data 埠9 can also be a bus for connecting an external device (such as a personal computer (PC)). Such as universal serial bus (USB) 个人, personal computer interface (Personal Computer Interface, PCI) and so on. If the processor chip of the controller 8 does not support the data, the 埠 converter 10 can be used to provide data conversion between the data 埠9 and the controller 8, such as a Universal Asynchronous Receiver/Transmitter (UART). )Wait.

The rapid prototyping device further includes a power source 11, a power stabilizer 12, and a regulator 13. The power source 11 provides power to the various components. The power stabilizer 12 is a device for stabilizing the power source, such as a voltage regulator. The regulator 13 is used to adjust the voltage and current supplied to the components, and the on/off control of the component power can be realized. The regulator 13 may be a metal-oxide-semiconductor (MOS), a metal-oxide-semiconductor field-effect transistor (MOSFET), a relay, or the like, or may be specially designed. The circuit is implemented.

FIG. 3 is a schematic diagram showing a control mechanism of a rapid prototyping apparatus according to an embodiment of the present invention. FIG. 4 is a flow chart showing a control method of a rapid prototyping apparatus according to an embodiment of the present invention. As shown in FIG. 3, the 3D printer can include a motor 31, a print head (not shown), a table (not shown), at least a first inductive element 32, a second inductive element 33, and a control assembly 34.

At least one first inductive element 32 is disposed on the rotor of the motor 31.

When the motor rotor rotates, the second sensing element 33 generates an inductive signal by the action of the at least one first sensing element 32 (step S41).

The control component 34 receives the sensing signal of the second sensing component, converts the sensing signal into a printing movement value, and generates a control according to the printing movement value and the preset printing data. A signal (step S42) for controlling the operation of the motor. The print movement value is a value indicating the moving distance of the print head or the work table.

The first sensing element 32 and the second sensing element 33 can be various feasible sensing devices, such as electromagnetic sensing elements, light sensing elements, infrared sensing elements, and the like. Figures 5a, 5b, and 5c show several examples of providing sensing elements in a rapid prototyping apparatus. In the example shown in FIG. 5a, the first sensing element 52 is disposed on the surface of the motor rotor at equal intervals in the rotational direction R of the motor rotor (for example, clockwise or counterclockwise), and the second sensing element 53 is disposed on the surface of the motor rotor. The inside of the motor casing 50. In the example shown in Fig. 5b, the first sensing element 52 is disposed on each of the blades (i.e., the convex portions) of the motor rotor 51. In the example shown in Fig. 5c, the first sensing elements 52 are disposed on the blades of the motor rotor 51 in an equally spaced manner, i.e., every other blade. In the example shown in FIG. 5d, the first sensing elements 52 are disposed in the grooves of the motor rotor 51 at equal intervals.

In one example, the first inductive element is a magnet, such as a magnetic steel; and the second inductive element is a Hall switch. The Hall switch can be disposed at any position in the magnetic field of at least one of the magnets, such as the inner wall of the motor casing. As the rotor rotates, the magnets are in turn close to and away from the Hall switch, causing the Hall switch to generate an induced current. Let Bnp be the magnetic induction intensity of the "open" of the working point, and BRP is the magnetic induction intensity of the "off" of the release point. When the applied magnetic induction exceeds Bnp, the Hall switch outputs a low level; when the magnetic induction decreases below Bnp, Huo The output level of the switch is unchanged; when the magnetic induction decreases to BRP, the output of the Hall switch transitions from low to high. Therefore, the angle at which the rotor turns can be calculated based on the number of pulses of the induced current received and the set interval of the magnet.

At least one magnet may be equally spaced in the direction of rotation of the motor rotor It is placed on the surface of the motor rotor. The magnet spacing can be determined based on factors such as control accuracy requirements and interference between the magnets. The smaller the interval between the magnets, the larger the number of magnets placed on the rotor, and the narrower the pulse width of the Hall switch output, so that the rotation of the rotor at a smaller angle can be recognized, which is advantageous for improving the control accuracy. In one example, a magnet can be placed on each blade of the motor rotor.

The motor 31 described above may be any one of a plurality of motors for controlling the movement of the print head or the table in the rapid prototyping apparatus, that is, the solution of the embodiment of the present invention may be applied to any or all of the motors. For example, when the above-described scheme is applied to the motor in the X-axis moving system 3, the movement of the printing head in the X-axis direction can be more precisely controlled, thereby improving the printing accuracy. The above description is based on only one of the motors, and the solution can be applied to other motors in the same manner.

Figure 6 is a schematic view showing a control mechanism of a rapid prototyping apparatus according to another embodiment of the present invention. As shown in FIG. 6, the control component 34 can include an analog to digital conversion unit 36, a counting unit 37, and a control signal generating unit 38. The analog/digital conversion unit 36 is configured to perform analog/digital conversion on the sensing signal to obtain a digital signal. The counting unit 37 is configured to count according to the digital signal and obtain the counting result. The control signal generating unit 38 is configured to generate a print shift value by using the count result.

In one example, the control signal is used to control the power on/off of the motor or to adjust the drive voltage or current of the motor.

In one example, the control signal generating unit 38 further includes: obtaining a target moving value according to the printed data, and comparing the printing moving value with the target moving value; and generating a control signal to disconnect when the printing moving value is equal to the target moving value. Motor power supply or control The signal is used to adjust at least one operating parameter of the motor; wherein the operating parameter is a driving voltage, a driving current, a pulse width of the driving current, or a frequency of the driving current. The print movement value can be the distance the print head or table moves along the rail, or the angle of rotation of the rotor.

Control component 34 can be implemented by the controller described above. It can be implemented by at least one component, such as a single chip microcomputer and a digital signal processor (DSP).

In one example, the control component 34 is configured to generate a control signal to disconnect the power of the motor or to adjust the motor to at least one operating parameter; wherein the operating parameter is the driving voltage, the driving current, the pulse width of the driving current, or the frequency of the driving current. For example, when it is determined that the calculated displacement or rotation angle reaches the target displacement or the target rotation angle, the control unit 34 can generate a control signal to disconnect the power supply of the motor. For another example, the control component 34 can perform the relationship between the displacement or the rotation angle and the target displacement or the target rotation angle on the operating parameters of the motor, such as the driving voltage, the driving current, the pulse width of the driving current, the frequency of the driving current, and the like. Adjustment. The specific operation of this adjustment is based on the type of motor actually used. For example, when a DC motor or a stepping motor is used, the width of the control current pulse can be adjusted by a pulse width modulator (PWM); when an AC motor or a variable frequency motor is used, the frequency of the control current can be adjusted by using a frequency converter. ,and many more.

The specific algorithm for converting the rotation angle of the motor rotor into displacement or converting the target displacement to the target rotation angle depends on the type of motor and the type and parameters of the transmission structure (such as screw, transmission gear and toothed belt). The parameters of the screw are mainly the pitch, the number of heads and the lead. The pitch refers to the axial direction of the corresponding point of the two adjacent teeth on the thread. distance. Usually indicated by P. The number of heads is the number of threads, for example, the double-headed screw has two non-intersecting spirals that are intertwined with each other. The lead refers to the axial distance of the corresponding point of the adjacent two teeth on the same spiral line, which can be represented by L. So if it is a single thread, the lead is equal to the pitch. If it is a multi-thread thread, the lead is equal to the number of heads multiplied by the pitch (L = nP). For example, the motor is pivoted with a 4 screw with a pitch of 2 mm (mm), such that the lead has a lead of 8 mm (mm), that is, 8 mm (mm) when the motor rotates once. The parameters of the gear and the toothed belt are mainly the number of teeth, the pitch of the toothed belt, and the like. For example, if the synchronous wheel used has 15 teeth and the pitch of the synchronous belt is 2 mm (mm), the motor rotates once, which will drive the synchronous wheel to rotate one revolution, that is, the distance of 15 teeth forward, corresponding to the timing belt, is the advance Distance of 30 mm (mm) (15 × 2).

Figure 7 is a block diagram showing the structure of a control signal generating device of a rapid prototyping apparatus according to an embodiment of the present invention. The control signal generating device includes a position adjuster, a speed regulator, a current regulator, a pulse width modulation (PWM) generator, a power driver, an inductor, and an analog/digital (A/D) converter. The power driver supplies a drive signal to the motor M. The inductor senses the rotation of the motor rotor and outputs the sensing signal to the analog/digital converter. The analog/digital converter supplies the inductive signal to the current regulator after analog-to-digital conversion. The current regulator adjusts the driving signal output to the pulse width modulation generator according to the output signal of the analog/digital converter, so that the pulse width modulation generator generates the pulse width modulation signal of the driving motor M according to the driving signal.

The control component further includes: generating a first control signal to the motor to provide a forward current to move the print head or the table in the first direction; and generating a second control signal to the motor to provide a reverse current to cause the print head or The table moves in a second direction opposite the first direction; wherein the motor is a direct current motor.

Figure 8a is a schematic structural view of a forward motion control device of a rapid prototyping apparatus according to an embodiment of the present invention. As shown in FIG. 8a, when the forward motion is required, the control component further includes: generating a first control signal to control the gear coupling of the passive shaft 82 gear and the driving shaft 81, and driving the driven shaft 82 gear under the driving of the driving shaft 81 gear. The print head or table moves in a first direction, ie, forward; wherein the motor is an AC motor.

Figure 8b is a schematic view showing the structure of a reverse motion control device of a rapid prototyping apparatus according to an embodiment of the present invention. As shown in FIG. 8b, when the reverse motion is required, the control component further includes: generating a second control signal to control the gear of the reverse shaft 83 to mesh with the gear of the drive shaft 81 and the passive shaft 82, respectively, and the gear of the drive shaft 81 and The driven shaft 82 is disengaged such that the print head or table is moved in the second direction opposite to the first direction, that is, reversed, by the gear of the driven shaft 82; wherein the motor is an AC motor.

It should be noted that not all the steps and modules in the above processes and the various structural diagrams are necessary, and some steps or modules may be omitted according to actual needs. The order of execution of each step is not fixed and can be adjusted as needed. The division of each module is only for the convenience of description. The actual implementation, a module can be implemented by multiple modules, and the functions of multiple modules can also be realized by the same module. Can be in the same device or in a different device.

In each case, the hardware may be implemented by specialized hardware or hardware that executes machine readable instructions. For example, the hardware can be specially designed permanent circuits or logic devices (such as dedicated processors such as field programmable gate arrays (FPGAs) or special application integrated circuits (ASICs)) for performing specific operations. The hardware may also include programmable logic devices or circuits (such as general purpose processors or other programmable processors) that are temporarily configured by software for implementation. Line specific operations.

The machine readable instructions corresponding to some of the modules in the figure may enable the operating system or the like operated on the computer to perform some or all of the operations described herein. The non-transitory computer readable storage medium may be a memory that is inserted into a memory set in an expansion board in the computer or written in an expansion unit connected to the computer. A central processing unit (CPU) or the like installed on the expansion board or the expansion unit can perform part and all actual operations according to the instructions.

In summary, the scope of the patent application should not be limited to the embodiments in the examples described above, but the specification should be construed as a whole and the broadest explanation.

3‧‧‧X-axis mobile system

4‧‧‧Y-axis mobile system

5‧‧‧Z-axis mobile system

6‧‧‧Printing device

7‧‧‧Workbench

8‧‧‧ Controller

9‧‧‧Information埠

10‧‧‧埠 converter

11‧‧‧Power supply

12‧‧‧Power Stabilizer

13‧‧‧Regulator

Claims (13)

A rapid prototyping device comprising: a motor; a printing head connected to the motor; a working table disposed under the printing head; at least one first sensing element disposed on one of the rotors of the motor; a sensing element, configured to generate an inductive signal by the at least one first sensing element when the rotor rotates; and a control component for receiving the sensing signal and generating a control signal to control the motor Operation, the motor is controlled by the control signal to further control the movement of the print head relative to the table. The rapid prototyping apparatus of claim 1, wherein the control component further comprises: an analog/digital conversion unit for performing analog/digital conversion on the inductive signal to obtain a digital signal; and a counting unit Counting the digital signal and obtaining a counting result; and a control signal generating unit for generating a printing movement value by using the counting result, wherein the printing movement value is movement of the printing head or the work station The distance, or the angle of rotation of one of the rotors. The rapid prototyping device of claim 2, wherein the control signal generating unit further comprises: obtaining a target moving value according to a printed data, and comparing the printing moving value with the target moving value; and when the column When the printing movement value is equal to the target movement value, the control signal is generated to disconnect the horse. And modulating at least one operating parameter of the motor; wherein the operating parameters are a driving voltage, a driving current, a pulse width of the driving current or a frequency of the driving current. The rapid prototyping device of claim 1, wherein the first inductive component is a magnet and the second inductive component is a Hall switch. The rapid prototyping apparatus of claim 1, wherein the at least one first inductive element is disposed on the rotor at equal intervals. The rapid prototyping apparatus of claim 1, wherein the control component further comprises: generating a first control signal to the motor to provide a forward current, so that the print head or the work station is along a first Moving in a direction; and generating a second control signal to the motor to provide a reverse current to move the printhead or the table in a second direction opposite the first direction; wherein the motor is a direct current motor . The rapid prototyping device of claim 1, further comprising: a drive shaft gear, a driven shaft gear, and a reverse shaft gear, wherein the control component further comprises: generating a first control signal to control the passive The shaft gear meshes with the drive shaft gear to drive the driven shaft gear to drive the print head or the table in a first direction under the driving of the drive shaft gear; and generate a second control signal to control the reverse gear The shaft gear meshes with the driving shaft gear and the driven shaft gear respectively, and separates the driving shaft gear from the driven shaft gear, so that the printing head or the working table is driven by the passive shaft gear and the first One of the opposite directions moves in a second direction; wherein the motor is an AC motor. A rapid prototyping device control method suitable for controlling a rapid prototyping device, the rapid prototyping device comprising a motor, a printing head connected to the motor, a working table disposed under the printing head, at least a first Inductive component, a second inductive component, and a control component, The method includes the steps of: disposing the at least one first sensing element on one of the rotors of the motor; and when the rotor rotates, using the second sensing element to generate an inductive signal under the action of the at least one first sensing element; and receiving Sensing the signal and generating a control signal to control the operation of the motor; wherein the control component receives the control signal and controls the motor by the control signal to further control the movement of the print head relative to the table . The method for controlling a rapid prototyping device according to claim 8, wherein the step of receiving the sensing signal and generating a control signal to control the operation of the motor further comprises the steps of: performing the analog signal on the analog signal. Converting to obtain a digital signal; counting the digital signal and obtaining a counting result; and generating a printing movement value by using the counting result, wherein the printing movement value is a moving distance of the printing head or the working table, or One of the rotation angles of the rotor. The method for controlling a rapid prototyping device according to claim 8, wherein the step of generating the printing movement value by using the counting result further comprises the steps of: obtaining a target moving value according to the printing data, and comparing The printing movement value and the target movement value; and when the printing movement value is equal to the target movement value, generating the control signal to disconnect the power of the motor, or adjusting at least one operating parameter; wherein the operating parameters are A motor drive voltage, a drive current, a pulse width of the drive current, or a frequency of the drive current. The method of controlling a rapid prototyping apparatus according to claim 8, wherein the first inductive element is a magnet and the second inductive element is a Hall switch. The control method of the rapid prototyping device described in claim 8 of the patent application further includes the following steps Step: generating a first control signal to the motor to provide a forward current to move the print head or the table in a first direction; and generating a second control signal to the motor to provide a reverse current Moving the printhead or the table in a second direction opposite the first direction; wherein the motor is a motor. The method for controlling a rapid prototyping device according to claim 8, further comprising the steps of: generating a first control signal to control a passive shaft gear to engage with a drive shaft gear such that the passive shaft gear is on the drive shaft Driven by the gear to drive the print head or the table to move in a first direction; and generate a second control signal to control a reverse shaft gear to mesh with the drive shaft gear and the driven shaft gear respectively, and The drive shaft gear is separated from the driven shaft gear such that the print head or the table moves in a second direction opposite to the first direction by the driven shaft gear; wherein the motor is an AC motor.