JP7019465B2 - 3D laminated modeling method and 3D laminated modeling equipment - Google Patents

Description

The present invention relates to a three-dimensional laminated modeling method and a three-dimensional laminated modeling apparatus.

A structure using an FFF (Fused Filament Fabrication) type three-dimensional laminated molding device has been proposed in order to cope with a complicated structure and high-mix low-volume production (see Patent Document 1).

The three-dimensional laminated modeling device is a device that forms a three-dimensional object while gradually "laminating" materials such as resin and metal based on three-dimensional data. In the FFF method, the melted amorphous resin is mainly extruded and laminated.

Special Table 2017-502852 (Fig. 3, Table 2)

The modeled object manufactured by the three-dimensional laminated modeling device has a problem that the strength in the stacking direction is low. Therefore, when a part is composed only of a modeled object manufactured by a three-dimensional laminated modeling device, the strength is often lower than the design required value, and it is difficult to apply it to aircraft parts and the like.

In particular, in the FFF method, the strength in the stacking height direction is low. The stacking height direction strength is the fusion strength for each layer. In Patent Document 1, a three-dimensional laminate is manufactured using a crystalline resin, but since the crystalline resin generally has poor fusion property, it is difficult for the lower layer and the upper layer to adhere to each other.

In Patent Document 1, the degree of crystallization is lowered by mixing the amorphous resin with the crystalline resin, thereby reducing the molding shrinkage due to crystallization and preventing the warp of the molded product.

However, mixing the amorphous resin loses the advantages of the crystalline resin, such as high strength and high heat resistance, and significantly limits the material selection.

The present invention has been made in view of such circumstances, and produces a three-dimensional laminated model having both high strength and high heat resistance of a crystalline resin and improved fusion strength between layers. It is an object of the present invention to provide a device and a method for the purpose.

In order to solve the above problems, the three-dimensional laminated modeling method and the three-dimensional laminated modeling apparatus of the present invention employ the following means.

The present invention is a method of laminating a resin layer on a platform to form a modeled object as a three-dimensional laminated body, wherein the crystalline thermoplastic resin is used as a material and heated and melted on the platform. When the material is discharged and the resin layer is laminated, the resin layer is cooled to a temperature equal to or lower than the glass transition temperature of the material within a predetermined time after the discharge, and the resin layer as a base is used when the resin layer is laminated. Of these, a tertiary layer in which the portion of the next layer immediately before laminating immediately before the material is discharged is locally reheated , and the model is annealed at a temperature higher than the glass transition temperature of the material and lower than the melting point of the material. The original laminated molding method is provided.

Further, the present invention supplies a resin having a platform, a heating unit capable of melting the crystalline thermoplastic resin, and a discharge head for discharging the crystalline thermoplastic resin heated and melted on the platform and laminating a resin layer. The crystalline heat of the next layer of the underlying resin layer when laminating the resin layer, the cooling unit that cools the resin layer to the glass transition temperature or lower within a predetermined time after the ejection, and the resin layer. Three-dimensional stacking including a reheating section capable of locally heating the portion immediately before stacking immediately before the plastic resin is discharged , and a control section for adjusting the cooling rate by the cooling section so that the predetermined time is within 2 seconds. Provides modeling equipment.

The crystalline thermoplastic resin melts when heated above the melting point. The melted crystalline thermoplastic resin is discharged onto the platform to form a resin layer. The crystallinity rate of the crystalline thermoplastic resin is maximum at the crystallization temperature and becomes 0 near the glass transition temperature (Tg). When the discharged material (resin layer) is cooled to the glass transition temperature or lower within a predetermined time, the crystallization progresses for a short time, and as a result, the crystallinity decreases and the amorphous portion increases. This makes it possible to promote the entanglement of molecular chains and the growth of spherulites at the fusion interface, and improve the fusion strength between the laminated resin layers. Specifically, it is rapidly cooled within a predetermined time of 2 seconds .

The higher the crystallinity of the crystalline thermoplastic resin, the better the mechanical properties such as elastic modulus and strength. The amorphous portion can be crystallized by annealing the laminate in the above temperature range. As a result, the physical and chemical properties can be improved, and the dimensional stability due to the release of internal strain can be improved.

While cooling is required for amorphization, if the temperature of the underlying resin layer is too low, the laminated resin layers cannot be fused together. In the above invention, when laminating the resin layer, the pre-layer and the next layer can be fused by locally reheating the portion immediately before laminating in the front layer (the resin layer as the base).

According to the present invention, by keeping the crystallinity of the crystalline thermoplastic resin during molding low, the crystalline thermoplastic resin has high strength and high heat resistance, and at the same time, the fusion strength between the resin layers is maintained. It is possible to manufacture a three-dimensional laminated model with improved results.

It is a schematic diagram of the three-dimensional laminated modeling apparatus which concerns on one Embodiment of this invention. It is a figure explaining the annealing process. It is a figure which shows the relationship between the cooling rate and the possibility of modeling.

Hereinafter, an embodiment of the three-dimensional laminated modeling apparatus and the three-dimensional laminated modeling method according to the present invention will be described with reference to the drawings.

[First Embodiment]
Hereinafter, the first embodiment of the present invention will be described with reference to FIG.

The three-dimensional laminated modeling device 1 includes a chamber 2, a platform 3, a resin supply unit 4, a cooling unit 5, a reheating unit 6, a temperature measurement unit 7, and a control unit 8.

The chamber 2 is a closed housing that can accommodate the modeled object (laminated body) 10 and the platform 3.

The platform 3 has a flat surface 3a. The flat surface 3a is arranged horizontally. The model 10 is printed layer by layer on the flat surface 3a of the platform 3.

The resin supply unit 4 has a heating unit (not shown) for melting the material of the modeled object 10, and a discharge head 4a for discharging (extruding) the melted material onto the platform 3. The heating unit is a heater or the like.

The discharge head 4a can extrude the melted material and laminate the resin layers (layers of the model) 10a and 10b on the platform 3. The discharge head 4a is configured to be movable in the xy plane in parallel with the flat surface 3a of the platform 3. Further, the discharge head 4a is configured to be movable along the vertical direction (z-axis).

In an alternative embodiment, the platform 3 may be configured to move along the xy plane and / or the z-axis. In another alternative embodiment, the discharge head 4a and the platform 3 may be configured to be movable with respect to each other. The existing moving mechanism can be adopted for the configuration for moving the discharge head 4a and / or the platform 3.

The cooling unit 5 is a blower or the like. In FIG. 1, a blower is used to blow wind (W) on the resin layers 10a and 10b. The cooling unit 5 is installed in the chamber 2 so as to cool a newly laminated region such as the resin layers 10a and 10b, particularly the resin layer 10a, where solidification is progressing. A plurality of cooling units 5 may be installed as needed. It is desirable that the cooling unit 5 has a cooling rate adjusting unit (not shown) so that the resin layer temperature can be lowered at a desired rate.

The reheating unit 6 is an infrared heating (IR) device, a laser heating device, or the like. The reheating unit 6 is installed in the chamber so that the optical path (L) of the infrared ray or the laser is not obstructed by the discharge head 4a. Further, the reheating unit 6 can locally reheat only the portion A immediately before stacking of the underlying resin layer (front layer) in front of the path of the discharge head 4a. It is desirable to narrow the beam diameter so that the heating spot diameter becomes the strand diameter of the molten resin.

The temperature measuring unit 7 is a non-contact temperature measuring device such as an infrared camera.

The control unit 8 is an information processing device configured to monitor and operate each element of the three-dimensional laminated modeling device. The control unit 8 controls the movement of the discharge head 4a (and / or the platform 3), the amount of resin extruded, and the like based on the three-dimensional data. Further, the control unit 8 adjusts the cooling speed by the cooling unit 5 according to the measurement result of the temperature measuring unit 7. The control unit 8 controls the reheating position and the like by the reheating unit 6 according to the operation of the discharge head.

The information processing device is composed of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. As an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the CPU reads this program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is installed in a ROM or other storage medium in advance, is provided in a state of being stored in a computer-readable storage medium, or is distributed via a wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

Next, a method of manufacturing a modeled object by using the three-dimensional laminated modeling apparatus 1 will be described.

A crystalline thermoplastic resin is used as the material of the modeled object. The crystalline thermoplastic resin is, for example, polyaryletherketone (PAEK). PAEK includes polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK) and the like.

The filamentary material is put into the resin supply unit 4, and the material is heated and melted in the heating unit. The melted material is discharged (extruded) from the discharge head 4a, and the resin layers 10a and 10b are further laminated on the platform 3. In FIG. 1, the resin layer 10b is a laminated body in which a plurality of resin layers are laminated.

While the resin layers 10a and 10b are laminated, the resin layers 10a and 10b are cooled by the cooling unit 5. In particular, the material extruded from the discharge head 4a (the newly laminated resin layer 10a) is rapidly cooled by the cooling unit 5. "Quenching" means cooling the material to Tg or less within a predetermined time after discharging the material. The predetermined time is within 2 seconds when the material is PEEK. The optimum predetermined time can be set based on the results of the preliminary test. For example, in a preliminary test, the cooling conditions under which the crystallinity of the resin layers 10a and 10b can be suppressed to 1/3 or less of the crystallinity (about 50% in PEEK) when the resin layers 10a and 10b are held at a high temperature for a sufficient time and annealed are performed are subjected to a preliminary test. Obtain it and quench it so as to satisfy the cooling conditions. The material before ejection maintains a temperature equal to or higher than the melting point so that the material extruded from the ejection head 4a does not solidify before laminating.

On the other hand, when laminating the resin layer 10a of the second and subsequent layers (next layer), the portion A immediately before laminating is locally reheated by the reheating portion. The reheating is carried out so that the surface temperature of the portion A immediately before stacking satisfies the formulas (1) and (2) when the material of the next layer is laminated on the reheated portion.
Melting point temperature of material (resin) -Surface temperature of portion A immediately before stacking <ΔT ... (1)
ΔT = Material temperature immediately after discharge-Melting point of material (resin) ... (2)
* The material temperature immediately after discharge = the discharge head temperature may be used.

The portion A immediately before stacking is a region of the front layer (resin layer 10b serving as a base) immediately before the material of the next layer is discharged.

As a method of locally reheating, IR irradiation and laser irradiation in which the spot is narrowed down to the strand diameter can be considered.

The cooling rate, the reheating position, and the like may be controlled based on the temperature of the resin layers 10a and 10b measured by the temperature measuring unit.

It is desirable that the laminated body (modeled object) 10 formed by laminating the resin layers 10a and 10b is annealed. The annealing temperature is higher than the Tg of the material and lower than the melting point of the material. For example, PEEK has a Tg of about 140 ° C to 150 ° C and a melting point of about 340 ° C to 350 ° C. More specifically, PEEK450G (manufactured by Victrex) has a Tg of 143 ° C and a melting point of 343 ° C.

Annealing may be performed inside the chamber of the three-dimensional laminated molding apparatus, or as shown in FIG. 2, the entire modeled object 10 (laminated body) supported by the support base 12 using an oven 11 or the like separately installed outside. May be kept at a high temperature. Annealing can be carried out in the same manner as a general annealing treatment applied to a metal or plastic for the purpose of improving the characteristics of a material or the like, except that the temperature range is set as described above.

FIG. 3 shows the relationship between the cooling rate and the possibility of modeling. In the figure, the horizontal axis is the time (seconds) after being extruded from the discharge head, and the vertical axis is the resin temperature (° C.).

The test conditions in FIG. 3 are as follows.
Material: PEEK
(Victrex PEEK450G, crystallization temperature is around 300 ° C)
Head temperature: 400 ° C
Nozzle tip hole diameter: 0.5 mm
Platform temperature: 100 ° C
Laminating speed: 10 mm / s
Blower wind speed: 0m / s to 1.86m / s

In the test of FIG. 3, the resin layer was air-cooled by blowing air at a predetermined wind speed using a blower. When the wind speed was slower than 0.4 m / s (dotted line in FIG. 3), the crystallization of the previous layer proceeded, so that it did not fuse with the resin layer of the next layer and could not be formed. On the other hand, when cooled at a wind speed of 0.4 m / s (solid line in FIG. 3), it was confirmed that modeling was possible. According to FIG. 3, it can be seen that the resin layers of the front layer and the next layer can be fused by keeping the time of staying at Tg or more after ejection within 2 seconds.

1 Three-dimensional laminated modeling device 2 Chamber 3 Platform 3a Flat surface 4 Resin supply unit 4a Discharge head 5 Cooling unit 6 Reheating unit 7 Temperature measuring unit 8 Control unit 10 Modeled object (laminated body)
10a, 10b Resin layer 11 Oven 12 Support stand

Claims (2)

It is a method of laminating a resin layer on a platform to form a modeled object as a three-dimensional laminated body.
Using crystalline thermoplastic resin as a material
The heat-melted material is discharged onto the platform to laminate the resin layer.
Within a predetermined time after the ejection, the resin layer is cooled to a temperature equal to or lower than the glass transition temperature of the material, and the resin layer is cooled to a temperature equal to or lower than the glass transition temperature of the material.
When laminating the resin layer, the portion of the underlying resin layer immediately before laminating immediately before the material of the next layer is discharged is locally reheated .
The model is annealed at a temperature higher than the glass transition temperature of the material and lower than the melting point of the material.
A three-dimensional laminated modeling method in which the predetermined time is within 2 seconds . Platform and
A heating unit capable of melting the crystalline thermoplastic resin, a resin supply unit having a discharge head for discharging the crystalline thermoplastic resin heated and melted on the platform, and laminating a resin layer, and a resin supply unit.
A cooling unit that cools the resin layer to a temperature below the glass transition temperature within a predetermined time after the discharge.
When laminating the resin layer, of the underlying resin layer, a reheating portion capable of locally heating the portion immediately before laminating immediately before the crystalline thermoplastic resin of the next layer is discharged is used.
A control unit that adjusts the cooling rate by the cooling unit so that the predetermined time is within 2 seconds.
3D laminated modeling device equipped with.

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