A fdm printer anti-winding filament box and a residual filament detection method thereof

Abstract

The application provides a kind of FDM printer anti-winding filament box, including filament box shell, the filament box shell outer end rotationally connected material box cover;Power interface and main control module are installed on the outer side of filament shell;The filament box shell is sequentially provided with filament channel, positioning roller group and tray mounting column in;Wherein the damper is placed in the tray mounting column to provide rotational resistance;Positioning roller group includes upper positioning roller and lower positioning roller arranged above and below;Tray is mounted on the tray mounting column;The lower part of the lower positioning roller is provided with electric heating net;Fan is provided in the lower part of electric heating net, and the right part of fan is provided with desiccant mounting rack, and electric heating net, fan, desiccant mounting rack are located in the lower part of the air circulation channel of filament box.The device of the application can prevent filament from over-spreading, the internal circulating dry air, and real-time monitoring of the remaining amount of filament.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fiber-reinforced composite material FDM printer material filament storage device, and particularly relates to a FDM printer anti-winding filament box and a remaining filament detection method thereof. BACKGROUND

[0002] Fused deposition modeling 3D printer is a kind of 3D printer that uses heat conduction to soften and extrude the filament and then deposits it into a shape. The most common raw material used is pre-impregnated filament, which is usually prepared into a shape and then wound on a filament disc. The mass of each disc of filament is generally 1-2 kg. During use, the filament is first unwound from the original state of being wound on the disc roller, then enters the heating area under the drive of the stepper motor of the printer extruder, and finally is softened and deposited into a shape. For fiber-reinforced resin-based composite filaments, since the resin matrix itself has a certain hygroscopicity, moisture entering the filament will vaporize in the extruded melt due to the increase in temperature during printing, resulting in printing defects. Therefore, certain moisture-proof treatment is required during the storage of the filament.

[0003] The filament box is a tool for temporarily storing the filament disc. Its working principle is to place the unsealed and connected filament disc into the box body, so that the filament disc can rotate inside to complete the unwinding of the filament. The unwound filament is output through the opening in the box wall and connected to the extruder. Usually, a heating unit is built in to heat the stored filament to prevent moisture absorption.

[0004] However, the existing filament box on the market often cannot control the moderate unwinding of the filament when facing short fiber reinforced PEEK composite materials and other filaments with high elasticity. This will cause the unwinding speed of the filament to be usually greater than the consumption speed of the filament by the printer during actual printing, and the phenomenon of excessive unwinding of the filament will accumulate as the printing progresses. Eventually, the over-wound filament will be tangled on the disc. The pulling of the filament by the extruder will cause the filament to bend at a certain position. As the pulling force increases, the radius of curvature increases, and when the maximum value of the radius of curvature that the filament can withstand is reached, the filament will irreversibly deform or break, seriously affecting the continuous operation of the printing. In addition, the filament released from the filament box is connected to the extruder of the FDM printer, and it is inevitable that the filament will be pulled back into the filament box due to the movement of the nozzle, increasing the risk of filament winding and affecting the continuous and stable operation of the printer. In addition, the existing filament box cannot accurately detect the remaining amount of filament in the filament box, which may cause the printing to be forced to stop due to insufficient remaining filament during printing. SUMMARY

[0005] To solve the above problems, the application discloses a kind of FDM printer anti-winding filament box and its residual filament detection method, ensure that filament winding cannot be wound, the residual filament content in filament box is accurately detected, improve efficiency.

[0006] A kind of FDM printer anti-winding filament box, including filament box shell, the front end side of the filament box shell is rotatably connected with material box cover;Power interface and main control module are all installed on the outside of filament box shell;The filament channel, positioning roller group and tray mounting column are sequentially arranged in the filament box shell;The lower part of the tray mounting column is provided with circulating air duct support;Wherein the end of tray mounting column is placed damper to provide rotational resistance;Positioning roller group includes upper positioning roller and lower positioning roller arranged in upper and lower;Tray is installed on the tray mounting column;Wherein the upper part of rotary air duct support is in open form and the gap between filament box shell forms air circulation channel;The air inlet end of the circulating air duct support is sequentially provided with fan and desiccant mounting rack;The bottom of the circulating air duct support is provided with electric heating net.

[0007] Further, the temperature sensor inside the filament box is located at the top of the inner cavity of the filament box shell.

[0008] Further, the upper positioning roller and the lower positioning roller are both one-way rollers, and the upper positioning roller is installed with a spring to control the adaptive up-and-down movement of the upper positioning roller.

[0009] Further, the filament box cover is connected with the filament box shell through a hinge, and the opening and closing of the filament box can be controlled by rotating the filament box cover.

[0010] Further, the left end of the tray mounting column is sleeved on the protruding part of the right end of the damper to realize the installation of the tray mounting column and the damper.

[0011] A residual filament detection method for a FDM printer anti-winding filament box, the working of internal electric heating net can be controlled by main control module pid regulation to control the temperature inside the filament box;The main control module controls the filament disc releasing speed in the filament box by controlling the resistance in the damper to prevent winding;The main control module calculates the amount of residual filament in the filament by detecting the data returned by the force sensor.

[0012] Further, the specific content is as follows:

[0013] m 盘 : the mass of the empty tray; m丝 : the mass of the wire wound on the tray when it is full; m: the mass of the wire and the tray; m 余丝 : the mass of the remaining wire; : the density of the wire; R 外 : the outer radius of the tray, which is also the radius of the remaining wire when the tray is full of wire; R 内 : the inner radius of the tray; R 余丝 : the radius of the wire's outer periphery when the remaining wire is wound on the tray; h: the thickness of the tray; A: the ratio of the volume of the wire after winding to the actual volume of the wire; M: the moment of the wire; M d : the moment of the damping wheel; F: the pulling force of the wire; : the constant of the circle; g: the acceleration of gravity; V 绕 : the volume of the wire that can be wound on the tray; V 丝 : the actual volume of the wire after winding the entire wire tray; V 盘余 : the winding volume of the remaining wire; V 余丝实 : the actual volume of the remaining wire; F: the force of the wire pulling the tray to rotate;

[0014] First, input the wire and control module: m 盘 , m 丝 , , R 外 , R 内 , h, F; A is calculated by built-in formula; The specific calculation is as follows:

[0015] R 外 2 * * h - R 内 2 * * h = V 绕

[0016] m 丝 / 丝 = V 丝

[0017] Then: A = V 绕 / V 丝

[0018] The mechanical sensor can detect the real-time value of the mass of the tray and the remaining wire, and convert it to force N through electrical signal;

[0019] N = m * g

[0020] m = m 盘 + m 余丝

[0021] The density calculation formula is:

[0022] V 余丝实 = (m - m 盘 ) / (m

[0023] The combination coefficient A is obtained:

[0024] V 盘余 = A * V 余丝实

[0025] Then

[0026] R 余丝 2 * * h – R 内 2 * * h = V 盘余

[0027] Solving:

[0028] R 余丝 =

[0029] According to the method that the product of the force and the moment of the wire on the roller balances the damping moment of the roller, a moment balance equation is established.

[0030] The wire moment is:

[0031] M = F * R 余丝

[0032] The moment balance equation is:

[0033] M d = M

[0034] Solving:

[0035] M d = F *

[0036] In the control module, F is set, when the remaining content of the wire changes, the remaining wire quality is converted to the moment Rwire of the wire acting on the roller through the above formula. A first function between the damping moment M d required by the roller and the measurement data N of the mechanical sensor is established, real-time adjustment of the roller damping is realized, and over-release of the wire during the unwinding process is prevented;

[0037] The wire remaining amount percentage calculation method is as follows:

[0038] From

[0039] m=N / g

[0040] m = m 盘 + m 余丝

[0041] get

[0042] m 余丝 = N / g - m 盘

[0043] then

[0044] remaining wire percentage = (m 余丝 / m 丝 ) * 100%

[0045] solved

[0046]

[0047] Therefore, the functional relationship between N and the percentage of remaining wire material is established, and the detection of the amount of remaining wire material can be completed by detecting the value of N.

[0048] The present application facilitates the installation of wire material, which can be drawn out of the wire material box through the distance between the two rollers. The electric heating net heating can realize the air circulation inside the wire material box in the power-on state. A desiccant mounting rack is provided with high-temperature-resistant desiccant, which dries the air passing around it. The power interface provides the wire material box with the required power, and the main control module controls the temperature control and damper size adjustment inside the wire material box. The electric heating net, fan and desiccant mounting rack are all located in the air circulation channel in the lower part of the wire material box. When the fan and heating net work, the air in the upper part of the wire material box enters the wire material loop first at the desiccant mounting rack, and then is heated to a specified temperature by the heating net and blown to the upper wire material, realizing the drying and heating of the wire material placed in the wire material box. The temperature measuring device inside the wire material box is located at the top of the wire material box, and then the pid control method is used to control the work of the heating net inside the wire material box, realizing the maintenance of the internal temperature of the wire material box at the set temperature.

[0049] The beneficial results of the present application are:

[0050] 1. The device of the present application can prevent excessive wire material, internal circulating dry air, and real-time monitoring of the remaining amount of wire material. The function of preventing excessive wire material is realized based on the adjustable damper and the mechanical one-way roller of the wire material outlet channel; the internal circulating dry air is realized by the fan, heating net, desiccant mounting rack and temperature measuring device; the real-time detection of the remaining amount of wire material is realized by the force sensor built in the material disc mounting column to monitor the force of the material disc on the wire material column.

[0051] 2、Compared with the existing FDM printer filament box, the filament box of the application first obtains the remaining amount of the remaining filament through the measuring device, and converts it into an electrical signal for adjusting the size of the damping in the electromagnetic damper, so that the resistance of the material disc during the rotation and dispensing process is adapted to the radius of curvature of the filament, preventing the filament from breaking due to excessive radius of curvature and excessive resistance during the dispensing process.

[0052] 3、Due to the setting of a set of single rollers at the outlet of the filament box, the filament discharged from the filament box will not be rewound into the filament box due to the external force generated by the movement of the nozzle, preventing the filament box inside the material disc from being wound due to the movement of the nozzle. Secondly, the force sensor built-in the filament box can detect the amount of filament remaining in the material box, preventing the printing from being interrupted due to insufficient amount of filament remaining during a single printing process.

[0053] 4、Finally, an air duct is provided at the bottom of the filament box, an electric heating net, a fan and a desiccant mounting rack are provided inside the air duct, and a high-temperature desiccant is installed therein. The desiccant is a high-temperature silica gel desiccant, which can be used below 200 degrees. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1, the filament box assembly of the application Figure 1 ;

[0055] Figure 2 , the filament box assembly of the application Figure 2 ;

[0056] Figure 3 , the cross-sectional view of the material disc mounting column installation structure;

[0057] Figure 4 , the filament box control circuit diagram of the application;

[0058] Figure 5 , the schematic diagram of filament calculation;

[0059] Figure 6 , the local enlarged view of the spring cooperating with the upper positioning roller.

[0060] LIST OF REFERENCE NUMBERS:

[0061] Wherein: 1-filament box shell, 2-filament channel, 3-upper positioning roller, 4-lower positioning roller, 5-main control module, 6-electric heating net, 7-desiccant mounting rack, 8-fan, 9-grip, 10-filament box cover, 11-filament box internal air flow channel, 12-material disc mounting column, 13-material disc, 14-force sensor, 15-filament, 16-damper, 17-temperature sensor, 18-mounting bracket; 19-roller moving track; 20-circulating air duct support; 21-spring. DETAILED DESCRIPTION

[0062] The present application is further illustrated by the following description and accompanying drawings, and it is to be understood that the same are intended to illustrate the application and not to limit the scope thereof. It is noted that the terms "front", "rear", "left", "right", "upper" and "lower" as used in the following description refer to directions in the drawings and the terms "inner" and "outer" refer to directions toward or away from the geometric center of the particular member.

[0063] The present application is a remaining filament detection method for a filament winding prevention filament cartridge of an FDM printer, and the specific structure is as shown in Figures 1-3 1 is a shell of the filament cartridge, which can separate the inside of the filament cartridge from the outside of the filament cartridge in cooperation with the cartridge cover 10 (after the cartridge cover is closed). The filament cartridge cover 10 is connected to the filament cartridge shell 1 through a hinge, and the opening and closing of the filament cartridge can be controlled by rotating.

[0064] 2 is a filament channel through which the filament is discharged from the inside of the filament cartridge; 3 and 4 are upper and lower positioning rollers, which provide positioning for the filament, and the positioning rollers are one-way rollers, which ensure that the filament 15 in the filament cartridge will not return to the filament cartridge under the action of external force after the filament 15 leaves the filament cartridge through the filament channel 2; 5 is a main control module, which is responsible for controlling the operation of the internal fan 8 and the damper 16; 6 is an electric heating net, which provides a high temperature for the inside of the filament cartridge, and the electric heating net is provided with a temperature detection device to measure the temperature; 7 is a desiccant mounting rack, which provides a position for placing the desiccant inside the filament cartridge; 8 is a fan, which provides circulating airflow for the inside of the filament cartridge; 9 is a handle, which is connected to the cartridge cover 10 to facilitate opening of the filament cartridge; 11 is an internal airflow channel of the filament cartridge, which is an airflow circulation channel inside the filament cartridge, and the low-temperature and high-humidity airflow moves along the internal airflow channel 11 under the action of the fan 8, and the humidity in the airflow is reduced under the action of the desiccant in the desiccant mounting rack 7, and then the low-temperature airflow is heated by the electric heating net 6 and finally blown into the filament cartridge; 12 is a tray mounting column, on which the tray 13 is mounted, and the column is provided with a damper 16 to provide rotational resistance and prevent the tray 13 mounted on the tray mounting column 12 from winding during the process of winding the filament 15; 13 is a tray, on which the filament 15 is wound, and the tray can be disassembled and assembled on the tray mounting column 12; 14 is a force sensor, which connects the tray mounting column 12 and the filament cartridge shell 1, and calculates the remaining filament 15 on the tray 13 by detecting the force on the tray mounting column 12.

[0065] As shown in Figure 3As shown, the left end of the tray mounting post 12 is sleeved over the protruding portion of the right end of the damper 16, completing the installation of the tray mounting post 12 and the damper 16. The left end of the damper 16 is connected to an L-shaped mounting bracket, and the lower end of the L-shaped mounting bracket is connected to the upper end of the force sensor 14. The lower end of the force sensor 14 is connected to the upper end of another L-shaped mounting bracket, and the left end of this L-shaped mounting bracket is connected to the wire box housing. The damper provides rotational damping for the tray mounting post, and the force sensor can detect the mass on the tray mounting post.

[0066] like Figure 6 The figure shows the installation of the upper positioning roller 3. One end of the upper positioning roller 3 is located in the roller moving track 19 and is connected to the lower end of the spring 21. The upper end of the spring 21 is connected to the upper inner wall of the roller moving track 19. In this mechanism, the roller can move upward under the action of an upward external force, compressing the spring, allowing the wire to pass through the gap between the upper and lower positioning rollers.

[0067] like Figure 4 and 5 The figure shows a schematic diagram of the filament box control circuit. The filament box uses a DC power supply, with a switch controlling the flow of current to the main control module. The main control module uses PID control to control the operation of the internal electric heating network and the temperature inside the filament box. The main control module controls the speed of the filament reel in the filament box by adjusting the resistance in the damper, thereby arranging the winding. The main control module calculates the amount of filament remaining in the filament by detecting data returned by the force sensor.

[0068] m 盘 : Mass of the empty tray; m 丝 : The mass of the wire wound when the reel is full; m: The sum of the mass of the wire and the reel; m 余丝 : The mass of the remaining wire; : density of the wire; R 外 : The outer radius of the material disc, which is also the radius of the remaining wire after the material disc is fully wound with wire; R 内 : Inner radius of the tray; R 余丝 : The radius of the wire when the remaining wire is wound on the disc; h: The thickness of the disc; A: Defined as the ratio of the volume of the wire after winding to the actual volume of the wire; M: The torque of the wire; M d : damping wheel torque; : pi; g: acceleration due to gravity; V 绕 : Volume of the wire that can be wound on the tray; V 丝 : The actual volume of the wire after it is wrapped around the entire wire coil; V 盘余 : The winding volume of the remaining wire; V 余丝实: actual volume of remaining wire; F: force when wire pulls the reel to rotate;

[0069] First input: m 盘 , m 丝 , , R 外 , R 内 , h, F; A is calculated by built-in formula; specific calculation as follows:

[0070] R 外 2 * * h – R 内 2 * * h = V 绕

[0071] m 丝 / 丝 = V 丝

[0072] Then: A=V 绕 / V 丝

[0073] Mechanical sensor can detect the real-time value of the sum of the reel and the remaining wire quality, and convert it into force N through electrical signal;

[0074] N = m * g

[0075] m = m 盘 + m 余丝

[0076] From the density calculation formula:

[0077] V 余丝实 = ( m - m 盘 ) /

[0078] Combined with the coefficient A:

[0079] V 盘余 = A * V 余丝实

[0080] Then

[0081] R 余丝 2 * * h – R 内 2 * * h = V 盘余

[0082] Solving:

[0083] R 余丝 =

[0084] According to the method of balancing the product of the force and the moment of the wire on the roller with the damping moment of the roller, a moment balance equation is established.

[0085] The wire moment is:

[0086] M = F * R 余丝

[0087] The moment balance equation is:

[0088] M d = M

[0089] Solving:

[0090] M d = F *

[0091] In the control module, F is set, when the remaining content of the wire changes, the remaining wire mass is converted to the moment Rresidual wire of the wire acting on the roller through the above formula. A first function between the damping moment M d required by the roller and the measurement data N of the mechanical sensor is established, real-time adjustment of the roller damping is realized, and over-release of the wire during the unwinding process is prevented;

[0092] The percentage calculation method of the remaining wire amount is as follows:

[0093] From

[0094] m=N / g

[0095] m = m 盘 + m 余丝

[0096] get

[0097] m 余丝 = N / g - m 盘

[0098] then

[0099] The percentage of the remaining wire = (m 余丝 / m 丝 ) * 100%

[0100] Solving

[0101]

[0102] Therefore, the function relationship between N and the percentage of the remaining wire material is established, and the detection of the remaining wire material can be completed by detecting the value of N.

[0103] The technical means disclosed in the technical scheme of the present application is not limited to the technical means disclosed in the above-mentioned embodiments, but also includes technical schemes composed of any combination of the above technical features.

Claims

1. An anti-entanglement filament box for an FDM printer, comprising a filament box housing (1), wherein one side of the front end of the filament box housing (1) is rotatably connected to a filament box cover (10); characterized in that: The power interface and the main control module (15) are both mounted on the outer side of the wire box housing (1); the wire box housing (1) is provided with a wire channel (2), a positioning roller group and a material tray mounting column (12) in sequence; a circulating air duct support (20) is provided below the material tray mounting column (12); a damper (16) is placed at the end of the material tray mounting column (12) to provide rotation resistance; the positioning roller group includes an upper positioning roller (3) and a lower positioning roller (4) arranged at the upper and lower ends; the material tray (13) is mounted on the material tray mounting column (12); the upper part of the circulating air duct support (20) is open and the gap between the upper part and the wire box housing (1) forms an air circulation system. Channel (11); the air inlet end of the circulating air duct support (20) is provided with a fan (8) and a desiccant mounting bracket (7) in sequence; the bottom of the circulating air duct support (20) is provided with an electric heating net (6); the left end of the tray mounting column (12) is sleeved on the protruding part of the right end of the damper (16) to realize the installation of the tray mounting column (12) and the damper (16); the left end of the damper (16) is connected to the L-shaped mounting bracket (18), and is connected to the upper end of the force sensor (14) through the lower end of the L-shaped mounting bracket, the lower end of the force sensor (14) is connected to the upper end of another L-shaped mounting bracket, and is connected to the wire box shell through the left end of the L-shaped mounting bracket.

2. The anti-winding filament box for FDM printer according to claim 1, characterized in that: The temperature sensor (17) inside the wire box is located at the top of the inner cavity of the wire box housing (1).

3. The anti-winding filament box for FDM printer according to claim 1, characterized in that: The upper positioning roller (3) and the lower positioning roller (4) are both one-way rollers. A spring is mounted on the mounting shaft of the upper positioning roller (3) to control the adaptive upward and downward movement of the upper positioning roller (3).

4. The anti-tangle filament box for FDM printer according to claim 1, characterized in that: The wire box cover (10) is connected to the wire box housing (1) via a hinge, and the opening and closing of the wire box are controlled by rotation; a handle (9) is provided on the wire box cover (10).

5. The method for detecting remaining filaments in an anti-winding filament box of an FDM printer according to any one of claims 1 to 4, characterized in that: The temperature inside the wire box is controlled by regulating the operation of the internal electric heating network through the main control module pid; the main control module controls the wire feeding speed of the wire disc in the wire box by controlling the resistance size in the damper to prevent entanglement; The main control module calculates the amount of remaining wire in the wire by detecting the data returned by the force sensor; the remaining amount of the remaining wire is obtained through the measuring device and converted into an electrical signal for adjusting the damping size in the electromagnetic damper, so that the resistance of the material tray during the rotation and discharge process is adapted to the curvature radius of the wire.

6. The method for detecting remaining filaments in an anti-winding filament box of an FDM printer according to claim 5, characterized in that: The specific contents are as follows: m 盘 : Mass of the empty tray; m 丝 : The quality of the wire wound when the reel is full; m: the sum of the mass of the wire and the tray; m 余丝 : The mass of the remaining wire; : density of the wire; R 外 : The outer radius of the material disc, which is also the radius of the remaining wire after the material disc is fully wound with wire; R 内 : Inner radius of the tray; R 余丝 : The radius of the outer surface of the wire when the remaining wire is wound on the material tray; h: thickness of the material disc; A: defined as the ratio of the volume of the wire after winding to the actual volume of the wire; M: wire torque; M d : damping wheel torque; : pi; g: acceleration due to gravity; V 绕 : Volume of the wire that can be wound on the tray; V 丝 : The actual volume of the wire after it is wrapped around the entire wire coil; V 盘余 : The winding volume of the remaining wire; V 余丝实 : The actual volume of the remaining wire; F: The force when the wire pulls the tray to rotate; First, enter in the main control module: m 盘 、m 丝 、 、R 外 、R 内 , h, F; A is calculated using the built-in formula; the specific calculation is as follows ; Then: A=V 绕 / V 丝 The mechanical sensor detects the real-time value of the sum of the mass of the material tray and the remaining wire material, and converts it into force N through an electrical signal; N = m * g m = m 盘 + m 余丝 According to the density calculation formula: Combining the coefficient A, we get: In 盘余 = A * V 余丝实 but The solution is: R 余丝 = ； The torque balance equation is established based on the method of balancing the roller damping torque by the product of the force and torque of the wire on the roller; The wire torque is: M = F * R 余丝 The moment balance equation is: M d = M The solution is: M d =F* ; Set F in the control module. When the remaining content of the wire changes, the remaining wire mass is converted into the torque of the wire acting on the roller through the above formula; establish the damping torque M required for the roller d A linear function of the measured data N of the mechanical sensor is used to achieve real-time adjustment of the roller damping to ensure that the wire does not over-release during the untangling process; The calculation method of wire remainder percentage is as follows: Depend on m=N / g m = m 盘 + m 余丝 have to m 余丝 = N / g - m 盘 but Percentage of remaining silk = (m 余丝 / m 丝 ) * 100% The solution is ,It can be seen that a functional relationship between N and the percentage of remaining wire is established, and the detection of the amount of remaining wire is completed by detecting the value of N.

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