JP7061472B2 - Resin filament test method, test equipment and evaluation equipment - Google Patents

Description

The present invention relates to a resin filament test method, a test device, and an evaluation device suitable for testing filaments for 3D printers.

Among 3D printers, the mechanism of the so-called Material Extension method is a three-dimensional structure in which a resin filament such as PLA wound on a bobbin or spool passes through a feeder (supply roller), and is composed of a metal nozzle and a heater. A modeled object is formed by being supplied to a directionally movable extruder, melting the resin, solidifying the resin while ejecting the resin from a thin nozzle, and repeating the lamination (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-105176

However, since the three-dimensional movable extruder moves in a complicated and small manner, various loads are applied during molding, and when a low quality resin filament is used, the resin filament breaks during molding and the resin filament breaks in the nozzle. Problems such as resin clogging occur.

The quality of the resin filament also affects the molding accuracy. The mechanism for feeding the resin, the shape of the nozzle, and the modeling size differ depending on each device manufacturer, but the modeling processability generally depends largely on the quality of the resin filament.

Such a decrease in modeling workability due to the quality of the resin filament leads to a great loss such as uneven modeling and interruption of modeling.

In order to avoid such loss, it is one of the effective means to construct a system that can test and evaluate the quality of the resin filament in advance, and for that purpose, the relationship between the quality of the resin filament and the formability is considered. It is important to develop a test device that can clarify and carry out the items that match it.

Based on such new findings, it is an object of the present invention to provide a test method, a test device, and an evaluation device for a resin filament that contributes to improvement of modeling workability by a 3D printer.

For example, in the case of metal wire, if there is quality deterioration, the electrical resistance changes or cracks occur inside, so inspection can be performed through non-destructive inspection such as electrical characteristic inspection and X-ray inspection. Such an inspection method is not appropriate for the above.

The resin filament needs to be controlled so that a constant amount can always be supplied by feeding the resin filament from the roll, introducing the resin filament into the extruder, melting the resin filament there, and extruding the resin filament from the nozzle, as shown in FIG. 1 (a). If the filament is not a high-quality filament but a low-quality filament as shown in FIG. 2B, or if the resin filament is mixed with foreign matter that cannot pass through the nozzle diameter as shown in FIGS. 2A and 2B. In some cases, it may appear as a phenomenon such as a change in the feed status or a clogging of the nozzle.

Therefore, the problem of the quality of the resin filament, which is a problem when modeling with a 3D printer, and its modeling processability were examined as follows.
(1) First, the following points can be mentioned as problems in the quality of the resin filament.
(A1) Distortion of the cross-sectional shape of the PLA filament (A2) Presence of thickness spots in the length direction of the filament (A3) When the diameter of the filament is not constant.
(A4) Presence of crude substances such as pebbles contained in PLA filaments (2) Next, the following points can be mentioned as problems in modeling processability due to the quality of the resin filaments.
(B1) The discharge amount of the resin is not constant and the molding accuracy is lowered.
(B2) Resin is not fed and resin clogging occurs.
(3) The following can be mentioned as the relationship between the problem of the quality of the resin filament and the problem of the formability.
Problem of (B1): Corresponds to (A1), (A2), (A3) Problem of (B2): Corresponds to (A1), (A2), (A3), (A4)

Therefore, in order to evaluate the quality of the resin filament, an evaluation device capable of (i) continuous discharge property evaluation, (ii) stable discharge evaluation, and (iii) foreign matter contamination test is required.

Based on the above, in the case of a resin filament, it is possible to evaluate whether or not the resin filament is of a quality that can withstand use by quantitatively grasping the feed state and the presence or absence of nozzle clogging.

Based on such findings, the present inventor has taken the following measures.

That is, the resin filament test method according to the present invention is a test method for evaluating the resin filament F for a 3D printer, as shown in the schematic diagram of FIG. 3, and is a test method for evaluating the resin filament F of the filament feeder 4 , the feed roller 41a. The resin filament is fed to the extruder 1 by setting the feeding speed of The actual feeding speed V of the resin filament F is detected based on the pulse output from the arranged encoder 12, and the pressure load at the time of filament feeding is in a state where the actual feeding speed V and the predetermined feeding speed Vo match. It is characterized by detecting Tq over time .

If the feeding speed V and the pressure load Tq are measured over time through such a test method, the homogeneity can be evaluated from, for example, the cross-sectional shape, diameter, thickness, etc. of the resin filament F that changes through the roll 1.

Further, if the set feed rate Vo and the actual feed rate V are different, the resin filament F does not properly follow the feed, and the possibility of breakage or foreign matter contamination due to insufficient strength can be grasped.

Further, if the pressure load Tq at the time of feeding is measured, it is possible to detect the viscosity abnormality as a value close to MFR (Melt Flow Rate), which is an index of the magnitude of the fluidity of the resin filament F, in addition to the clogging due to the inclusion of foreign matter. ..

In the resin filament test method according to the present invention, it is preferable to detect the pressure load (torque) Tq by using the drive current Id of the motor 10 that rotationally drives the feed roller 41a.
Since the drive current Id of the motor 10 changes when the pressure load fluctuates, it is possible to detect the pressure load without separately providing a torque detector or the like by using this.
In the resin filament test method according to the present invention, as the evaluation of the resin filament F, the first evaluation item (i) of whether or not the resin filament F is continuously discharged, or the resin filament is stably discharged. It is possible to evaluate a part or all of the second evaluation item (ii) of whether or not the resin filament is mixed, or the third evaluation item (iii) of whether or not foreign matter is mixed in the resin filament. preferable.
By doing so, it becomes possible to evaluate the quality of the resin filament suitable for a special purpose such as a 3D printer.
In this case, it is effective to select nozzles 2 (for example, 2a to 2c) having different nozzle diameters attached to the extruder 1 for the common resin filament F and perform the test.

By changing the nozzle diameter in this way and performing the measurement, it is possible to detect the contamination of foreign matter of various sizes or unknown.

Further, as a test device Dt for evaluating the resin filament F for a 3D printer, as shown in FIG. 3, a holding portion 3 for holding the resin filament F wound around the roll R and a holding portion 3 below the holding portion 3 are used. A filament feeding portion 4 for feeding the resin filament F from the roll R and a resin filament F fed below the filament feeding portion 4 are introduced and melted by the heater 5 so as to be coaxial with any of the nozzles 2a to 2c. It has an extruder 1 to be extruded , an encoder 12 arranged between the holding unit 3 and the filament feeding unit 4, and a control unit 7 to control the motor 10, and the filament feeding unit 4 is provided by the motor 10. It has a feed roller 41a that is rotationally driven to feed the resin filament F to the extruder 1, and the control unit 7 controls the motor 10 so that the feed speed of the feed roller 41a becomes a predetermined feed speed Vo. At the same time, the actual feeding speed V of the resin filament F is detected based on the pulse output from the encoder 12, and the pressure load at the time of filament feeding is in a state where the actual feeding speed V and the predetermined feeding speed Vo match. It is preferable to detect Tq over time .

If the resin filament F is extruded coaxially from the filament feeder 4 toward the nozzles 2a to 2c, the clogging at the nozzles 2a to 2c is immediately captured as a pressure load of the filament feeder 4 via the extruder 1. Be done. Further, since the simulated printing mechanism P is configured to actually melt, soften, and reduce the diameter of the resin filament F and extrude it from the nozzles 2a to 2c, the resin filament F is tested in a state close to the actual usage environment of the 3D printer. It can be carried out.

In the resin filament test apparatus according to the present invention, it is preferable that the control unit 7 detects the pressure load (torque) Tq by using the drive current Id of the motor 10 .

Since the drive current Id of the servomotor 10 changes when the pressure load fluctuates, it is possible to detect the pressure load without separately providing a torque detector or the like by using this.

Also in this case, it is preferable that a plurality of extruders 1 having different nozzle diameters are provided side by side, and one of them is selected to introduce the resin filament F from the filament feeding portion 4.

By doing so, it is possible to easily change the nozzle diameter and perform the measurement, so that it is possible to catch the contamination of foreign matter having various sizes or unknown.

In the resin filament test apparatus according to the present invention, as an evaluation of the resin filament F, the first evaluation item (i) of whether or not the resin filament F is continuously discharged, or the resin filament is stably discharged. It is possible to evaluate a part or all of the second evaluation item (ii) of whether or not the resin filament is mixed, or the third evaluation item (iii) of whether or not foreign matter is mixed in the resin filament. preferable.

By doing so, it becomes possible to evaluate the quality of the resin filament suitable for a special purpose such as a 3D printer.

According to the present invention described above, it is possible to provide a novel and useful resin filament test method, test device, and evaluation device that contribute to the improvement of modeling workability by a 3D printer.

The figure which shows the quality of a resin filament schematically. The figure which shows the quality of a resin filament schematically. The schematic diagram which shows the test method and the test apparatus of the resin filament which concerns on this invention. The figure which extracts a part of FIG. 3 and shows schematically. The figure which shows one embodiment which embodied the schematic diagram of FIG. The explanatory view of the resin filament which was evaluated in one Example of this invention. The graph output in the same embodiment. Numerical table output in the same embodiment. The figure which shows the evaluation result of the same Example.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 5 shows an actual configuration of the test apparatus based on the schematic diagram of FIG.

In this test device, the roll R around which the filament F is wound on the support base 21 via a horizontal shaft 22 is detachable, and the roll R rotates via a bearing provided between the roll R and the shaft 22. However, the structure is such that the resin filament F is fed out.

An intermediate table 23 is arranged below the resin filament F, and a plurality of extruders 1 are attached to the intermediate table 23 at predetermined intervals. The extruder 1 is composed of a heater (heater block) 5 and a nozzle 2 and is attached below the intermediate table 23. The internal flow path of the nozzle 2 has a small diameter portion 2a as schematically shown in FIG. The feeder 41, which is a filament feeding device 4, is attached to the large diameter portion, which is opened downward and the large diameter portion 2b is opened upward, via the connecting metal fitting 24 schematically shown in FIG.

As schematically shown in FIG. 4, the feeder 41 includes a feed roller 41a having an uneven surface, a pinch roller 41b that sandwiches a resin filament F between the feed roller 41a, and a feed roller 41a. It is equipped with a rotary drive servo motor 10, and has a configuration in which the resin filament F unwound from the roll R is drawn into the feed roller 41a and the pinch roller 41b and sent out toward the feed roller 41a. The resin filament F is sent to the extruder 1 with a pressure load F corresponding to the rotational torque of the feed roller 41a.

As for the feed rate Vo of the servomotor 10 and the temperature T0 of the heater 5, the personal computer (hereinafter referred to as PC) shown in FIG. 5 functions as the control unit 7 shown in FIG. 3, and the feed rate V0 and the extrusion temperature T0 are input. By doing so, control is possible. The pressure load Tq and the filament temperature T at the time of filament feeding can also be monitored. Further, an encoder 12 is arranged between the feeder 41 and the roll R, and the resin filament F is sandwiched between the pair of pressure welding rollers 12a and 12a constituting the encoder 12, and the pulse output from the encoder 12 is digitally generated. It can be read by the multimeter 24 and input to the personal computer PC to evaluate the actual measured value of the actual feeding speed V of the resin filament F.

In the personal computer PC, in addition to the above-mentioned setting of the feeding speed V0 and the extrusion temperature T0, it is possible to control the start / stop of the entire printer mechanism P and set the timer, and the time from the start of feeding the resin filament F is also possible. It is said to be measurable.

The personal computer PC also functions as a data processing unit 9 and a command generation / output unit 11 in FIG.

Here, examples of the present invention will be described.

FIG. 6 shows PLA filaments A, B, and C, which are resin filaments to be evaluated.

The following are the evaluation conditions.
(i) Evaluation of continuous ejection performance

The PLA filament was fed at a constant speed, and it was verified whether the resin could be continuously ejected from the nozzle.
(specification)
・ Nozzle used: Φ0.4 mm,

Feeding speed: 220 mm / min
・ Nozzle set temperature: 220 ℃, 240 ℃
・ PLA filament usage: 1 bobbin roll or 15 hours continuous discharge
(ii) Evaluation of stable ejection performance The evaluation of the ejection amount was verified by keeping the extrusion speed of the PLA filament constant.
(specification)
・ Evaluation of discharge amount per unit time
・ Evaluation of the load current set sent to the servo motor
・ Nozzle set temperature: 220 ℃, 240 ℃
・ PLA filament usage: 1 bobbin roll or 15 hours continuous discharge
(iii) Foreign matter contamination test By changing the size of the nozzle opening (φ0.2 mm, 0.3 mm, 0.4 mm), it is verified whether or not there is contamination of coarse matter larger than the nozzle opening (specifications).
・ Nozzle opening size: φ0.2 mm, 0.3 mm, 0.4 mm
・ Nozzle set temperature: 240 ℃
・ PLA filament usage: 1 bobbin roll or 15 hours continuous discharge <evaluation data>

The evaluation data is output as graphs Gr1 to Gr3 in FIG. 7 or a numerical table Tab in FIG. The numerical table Tab represents the average value of the load factor.
<Evaluation result>

FIG. 9 shows the evaluation results. Here, (i) A to C are displayed as ○ (pass) for continuous ejection property evaluation, (ii) values indicating the degree of variation of A to C are displayed for stable ejection property evaluation, and (iii) foreign matter contamination degree test. With regard to, all nozzle diameters were ○ (passed).

Here, if the resin filament has the defects A1 to A4 described in the section of the problem-solving means, it appears as a symptom of B1 and B2. An abnormal state appears, and the evaluation result of quality defect is obtained in the evaluation result of FIG.

Although one embodiment and one embodiment of the present invention have been described above, the specific methods and configurations of each part are not limited to the above-mentioned embodiments and examples, and are within the scope of the present invention. Various deformations are possible.

1 ... Extruder 2, 2a-2c ... Nozzle 3 ... Holding unit 4 ... Filament feed unit 5 ... Heater 7 ... Control unit 8 ... Detection unit 9 ... Data processing unit 10 ... Servo motor 11 ... Index generation / output unit De ... Evaluation Device Dt ... Test device F ... Resin filament Gr1 to Gr5 ... Graph Id ... Drive current P ... Simulated print mechanism R ... Roll Tab ... Numerical table Tq ... Pressure load V ... Actual feed rate Vo ... Feed speed

Claims (6)

A test method for evaluating resin filaments for 3D printers.
An encoder arranged on the upstream side of the filament feeder while feeding the resin filament to the extruder by setting the feed roller of the feed roller of the filament feeder to a predetermined feed speed, melting the resin filament in the extruder and extruding the resin filament from the nozzle. The feature is that the actual feeding speed of the resin filament is detected based on the pulse output from the resin filament, and the pressure load at the time of filament feeding is detected over time in a state where the actual feeding speed and the predetermined feeding speed match. Test method for resin filaments. The method for testing a resin filament according to claim 1, wherein a pressure load is detected by using a drive current of a motor that rotationally drives the feed roller. As an evaluation of the resin filament, the first evaluation item of whether or not the resin filament is continuously ejected, the second evaluation item of whether or not the resin filament is stably ejected, or a foreign substance on the resin filament. The method for testing a resin filament according to claim 1 or 2, wherein any part or all of the third evaluation item as to whether or not the resin is mixed is evaluated. A test device for evaluating resin filaments for 3D printers.
A heater that introduces a holding portion that holds the resin filament wound around the roll, a filament feeding portion that is below the holding portion and feeds out the resin filament from the roll, and a resin filament that is below the filament feeding portion and is fed out. It has an extruder that is melted and extruded coaxially from a nozzle , an encoder that is arranged between the holding portion and the filament feeding portion, and a control unit that controls a motor.
The filament feeder has a feed roller that is rotationally driven by the motor to feed the resin filament to the extruder.
The control unit controls the motor so that the feeding speed of the feed roller becomes a predetermined feeding speed, and detects the actual feeding speed of the resin filament based on the pulse output from the encoder, and the actual feeding speed thereof. A resin filament test apparatus for detecting a pressure load at the time of filament feeding over time in a state where the speed and the predetermined feeding speed match . The resin filament test apparatus according to claim 4, wherein the control unit detects a pressure load by using the drive current of the motor. As an evaluation of the resin filament, the first evaluation item of whether or not the resin filament is continuously ejected, the second evaluation item of whether or not the resin filament is stably ejected, or a foreign substance on the resin filament. The resin filament test apparatus according to claim 4 or 5, which evaluates any part or all of the third evaluation item as to whether or not the resin is mixed.

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