JP2017136829A - Method for creating mold, mold creation device, and method for molding model material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a mold formable on-demand, reduced in a load upon release, and also high in dimensional accuracy.SOLUTION: Provided is a method for creating a mold made of the laminate of gel, using a polymer solution having a sol-gel transition temperature, formed under a temperature environment where a stage 20 or its atmosphere is higher than a sol-gel transition temperature, comprising: a step where a droplet discharge mechanism 10 discharging a polymer solution and the stage 20 are relatively moved to form a layer of gel having the locus of the relative movement on the stage 20; and a step where a polymer solution is further discharged to the surface of the layer of the gel by the droplet discharge mechanism 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mold creation method, a mold creation apparatus, and a model material molding method.

When a three-dimensional structure of a fragile material such as a hydrogel or a biomaterial is molded with a conventional mold made of metal or plastic, there are two problems.
The first problem is that the on-demand property is low. In order to form a mold, a process of machining a metal or plastic material by cutting or the like is first required. When the shape of the gel to be molded changes, it is necessary to newly manufacture the mold by cutting.
The second problem is that a load due to mold release is applied. When the molded gel is removed from the mold, friction may occur between the inner wall of the mold and the molded product, and the molded product may be destroyed.

  Further, as a method for obtaining a three-dimensional structure by laminating a temperature-responsive sol-gel transition material, a method described in Patent Document 1 (Japanese Patent Publication No. 2013-542728) is known. However, Patent Document 1 does not describe a concept for using a three-dimensional structure as a mold.

  The present invention has been made in view of the conventional problems in the case of casting a fragile material, and the object thereof is to form a fragile material by forming a mold that can be formed on demand and has a small load during mold release. It is possible to cast a three-dimensional structure.

  The present invention includes a step of discharging a polymer solution having a sol-gel transition temperature, which is solated at a temperature lower than the sol-gel transition temperature and gelled at a temperature higher than the sol-gel transition temperature, onto a stage by a droplet discharge mechanism; A step of maintaining the polymer solution discharged to the stage at a temperature higher than a sol-gel transition temperature, and moving the droplet discharge mechanism and the stage relative to each other to move the relative movement locus on the stage. And a step of discharging the polymer solution further onto the gel layer by the droplet discharge mechanism.

  According to the present invention, it is possible to form a mold that can be formed on demand, has a small load during mold release, and can cast a three-dimensional structure of a fragile material.

It is a figure which shows roughly the additive manufacturing apparatus which enforces the production method of the casting_mold | template concerning 1st Embodiment. It is a top view of a laminated body. FIG. 3 is a cross-sectional view taken along line AB in FIG. 2 in the vertical direction. It is a figure for demonstrating the process of removing the level | step difference inside a laminated body using cold air. It is sectional drawing of the laminated body which shows the state which removed the level | step difference between the layers of an inner wall by operation of the process A to the process F. It is sectional drawing of the laminated body which shows the state which removed the level | step difference between layers at the time of applying cold air not only to an inner wall but the whole laminated body. It is a figure which shows roughly the additive manufacturing apparatus which enforces the preparation method of the casting_mold | template concerning 2nd Embodiment. It is a figure which shows roughly the additive manufacturing apparatus which enforces the preparation method of the casting_mold | template concerning 3rd Embodiment. It is sectional drawing of the laminated body obtained by laminating | stacking 1 layer or several layers of gel on a stage. It is sectional drawing of the laminated body which shows the state which cooled the surface of the gel of the laminated body shown in FIG. 9, and removed the level | step difference between layers. It is sectional drawing of the laminated body which shows the state which laminated | stacked one layer or several layers of gel again on the laminated | stacked gel of the laminated body shown in FIG. It is sectional drawing of the laminated body which shows the state which cooled the surface near the uppermost step of the gel which laminated | stacked the laminated body shown in FIG. 11, and removed the level | step difference between layers. It is a figure for demonstrating the method to inject | pour the solution of a model material. It is a figure for demonstrating the hardened | cured model material. It is a figure for demonstrating the method to take out the model material cast to the target shape. 6 is a schematic view of a gel mold according to Example 5. FIG. 7 is a schematic view of a gel casting according to Example 5. FIG. 6 is a schematic view of a gel mold according to Example 6. FIG. 6 is a schematic view of a gel casting according to Example 6. FIG.

Embodiments of the present invention will be described with reference to the accompanying drawings.
The mold making method according to the present embodiment differs depending on whether the sol-gel transition temperature of the sol-gel transition material used for the mold is higher than room temperature or lower than room temperature in the space where the layered manufacturing apparatus described later is used.
When the sol-gel transition temperature is lower than room temperature, the mold is formed by discharging a polymer solution in a gel state. When the sol-gel transition temperature is higher than room temperature, the mold is formed by discharging a sol-state polymer solution. To do. In other words, in the present invention, the polymer solution may be discharged in a sol state or a gel state.
In addition, when the sol-gel transition temperature is higher than room temperature, the stage or surrounding atmosphere in the layered manufacturing apparatus is higher than the sol-gel transition temperature in order to prevent the gel polymer solution constituting the modeled object from being solated. It is desirable to hold on. As means for realizing this, it is possible to use a heating mechanism such as heating the stage and the syringe with a Peltier element, or modeling in a heating environment inside the thermostat.
In general, the room temperature is 20 ± 15 ° C., and the room temperature using the layered manufacturing apparatus described later is preferably about 15 ° C. to 25 ° C. Here, the room temperature using the additive manufacturing apparatus is set to 20 ° C.

[First Embodiment]
First, a case where a sol-gel transition temperature of a polymer solution is lower than room temperature and a polymer solution in a gel state is discharged to mold a mold will be described.
A mold making apparatus for forming a mold is roughly divided into two types: a layered modeling apparatus and a laminate cooling means.
FIG. 1 is a diagram schematically showing an additive manufacturing apparatus 1A that implements a method for producing a mold according to a first embodiment.
The additive manufacturing apparatus 1A includes a droplet discharge mechanism 10 that discharges a polymer solution, a stage 20 that receives the discharged polymer solution, and a drive unit that relatively moves the droplet discharge unit 12 of the droplet discharge mechanism 10 and the stage 20. 30 and so on.

Examples of the droplet discharge mechanism 10 include, but are not limited to, mechanical extrusion using a pneumatic dispenser, a syringe pump, and electrostatic discharge. Here, the case where the pneumatic dispenser 35 is used will be described. In this case, a syringe is used as the droplet discharge means 12.
The stage 20 has a flat upper surface (including a substantially flat shape), and the material of the stage 20 is not particularly limited as long as the polymer solution is attached thereto, and examples thereof include metals, glass, and plastic films.
The drive unit 30 moves at least one of the droplet discharge unit 12 and the stage 20 to relatively move the droplet discharge unit 12 and the stage 20 in a three-dimensional direction, and examples of the driving force include a motor and air pressure. . In the case of a motor drive, a ball screw or a belt drive actuator can be used. In the case of pneumatic driving, a pneumatic cylinder is used. However, the driving force and the configuration of the driving stage are arbitrary and are not limited thereto.

Next, the laminate cooling means will be described.
As will be described in detail later, the mold obtained by the layered manufacturing may cause a step due to the layering on the surface. Although it is not essential to prevent the step of the mold from being transferred to the model material, a step of removing the step on the surface of the mold may be sandwiched by solification of a part of the mold.
In the present specification, a solid casting obtained by pouring into a mold in a liquid form, curing in the mold, and taking out from the mold, and its material are expressed as a model material.
In order to remove the step on the surface of the mold, the laminate cooling means 2 (FIG. 4) used as a step of temporarily cooling the surface of the mold is a three-dimensional modeled gel (hereinafter referred to as a three-dimensional modeled object) modeled by the additive manufacturing apparatus 1A. It is a cooling means for cooling the surface of 40 (FIGS. 2 and 3) to a sol-gel transition temperature or lower, and includes means such as applying cold air, putting it in a refrigerator, or applying a cooled iron. However, it is not limited to these.
In particular, when locally cooling the surface of an intricate structure, means using cold air C (FIG. 4) that can be locally cooled without contact is desirable. Examples of the method for generating the cold air C include, but are not limited to, a jet cooler using compressed air.

  The polymer solution includes one having a sol-gel transition temperature and a sol-gel transition time within 10 minutes. Therefore, if the time for cooling the polymer solution below the sol-gel transition temperature is long, the entire laminate 40 may be solated and the structure may be collapsed. Therefore, the time for using the laminate cooling means is preferably 5 seconds or more and 10 minutes or less. Furthermore, 10 seconds or more and 5 minutes or less are desirable.

Further, in order to complete the sol formation by cooling the surface of the gel laminate 40 within the above time, the cooling temperature is preferably 5 ° C. or more lower than the sol-gel transition temperature.
Therefore, the cooling temperature is desirably 5 ° C. or more lower than the sol-gel transition temperature.

Next, the polymer solution to be used will be described.
In this embodiment, a polymer solution having a sol-gel transition temperature that forms a sol at a temperature lower than the sol-gel transition temperature and gels at a temperature higher than the sol-gel transition temperature is used as a material for forming the template. .
This polymer solution is a temperature-responsive sol-gel transition material whose aqueous solution becomes a temperature-responsive sol-gel transition material, that is, the aqueous solution is solated at a temperature lower than the sol-gel transition temperature and is gelled at a temperature higher than the sol-gel transition temperature. It is an aqueous solution of a hydrogel-forming polymer having a sol-gel transition temperature.
Examples of this hydrogel-forming polymer include methylcellulose, 8-arms PEG-block-PLLA-cholesterol conjugate shown in Patent Document 2 (Patent No. 5019851), and Patent Document 3 (Patent No. 5264103). Poly [(Glc-Asp) -r-DL-LA] -g-PEG shown, poloxamer 407 is commercially available under the names Pluronic ™ F127 and Kolliphor ™ P407. However, it is not limited to these.

Poloxamer 407 (hereinafter referred to as poloxamer) is desirable from the viewpoint that an aqueous solution can undergo a sol-gel transition near room temperature, availability, and actual use.
When using a poloxamer aqueous solution as a polymer solution having a sol-gel transition temperature, the sol-gel transition temperature can be adjusted by changing the concentration of the poloxamer.
For example, when the concentration is 20 weight percent, the temperature is about 20 ° C., and when the concentration is 15 weight percent, the temperature is about 30 to 40 ° C. The aqueous poloxamer solution having a concentration of 25 weight percent has a transition temperature of around 15 ° C., but when sodium chloride is added, the sol-gel transition temperature can be adjusted from 5 ° C. to about 10 ° C.
By varying the poloxamer concentration and additives, a sol-gel transition temperature lower than the casting temperature of the material to be molded inside the mold can be selected.
Also, the combination of methylcellulose and sorbitol used for food additives has a sol-gel transition temperature below 40 ° C. and is highly available.
Hereinafter, a hydrogel of a temperature-responsive hydrogel-forming polymer may be referred to as a “template gel”.

Next, a method for forming a mold which is a cylindrical laminate 40 made of a mold gel will be described. In addition, the shape of the casting_mold | template shown in this Embodiment is an example to the last, It is not limited to this. Examples include a bowl shape, a cup shape, and a shape in which a depression is provided on the surface of a three-dimensional shape such as a quadrangular prism or a sphere. The shape of the mold is a three-dimensional object, and is not particularly limited as long as it has a cavity or a depression communicating with the surface of the three-dimensional object.
A droplet discharge means 12 containing a polymer solution in a gel state at room temperature is prepared. Then, the following steps are executed. That is,
Step 1: The polymer solution is discharged from the droplet discharge means 12 onto the stage 20 using the droplet discharge mechanism 10. In this case, the stage 20 is assumed to be in a temperature environment higher than the sol-gel transition temperature. Further, the droplet discharge means 12 discharges the polymer solution in a gel state at a temperature equal to or higher than the sol-gel transition temperature, or discharges the polymer solution in a sol state at a temperature lower than the sol-gel transition temperature, It may be gelled by raising the temperature on the stage.
Step 2: Using the driving unit 30, the droplet discharge means 12 and the stage 20 are relatively moved in the horizontal direction.
Step 3: Form a mold gel layer in the shape of a relative movement locus on the stage 20.

Step 4: While moving the drive unit 30, the polymer solution is further discharged onto the formed mold gel layer, and the mold gel layer is stacked. When forming the template gel layer, a layer including a portion where the template gel is not formed is formed by securing a region where the polymer solution is not discharged inside the outer periphery of the layer.
By repeating steps 1 to 4, the operation of overlapping the layers of the polymer gel for the polymer solution is repeated to form a template that is a laminate made of the template gel.
FIG. 2 is a top view of the laminate, and FIG. 3 is a cross-sectional view taken along line AB in FIG. 2 in the vertical direction.
A mold can be formed by the above method. However, in the present invention, as long as the molding method of the mold is a layered modeling method, the means for discharging the gel, the drive unit, and the stage are not particularly limited.
In the mold obtained by the layered modeling, a step due to the layering may occur on the surface. In order to prevent the step of the mold from being transferred to the model material, although not essential, a step of removing the step on the surface of the mold may be interposed. Examples of this step include a step of temporarily cooling the gel laminate 40 described below during and / or after the lamination. By temporarily solating only the surface portion of the mold, the solated temperature-responsive hydrogel fills the steps of the mold to remove the steps.

Next, a method for temporarily cooling the mold gel laminate 40 will be described.
First, it is assumed that the gel laminate 40 formed using the layered manufacturing apparatus 1 is maintained on the stage 20 at a temperature equal to or higher than the sol-gel transition temperature.
Next, the surface of the gel laminate 40 is temporarily returned to the sol-gel transition temperature or lower using the laminate cooling means described above. As a result, when the surface portion of the laminate 40 is made into a sol, the sol on the surface portion flows downward due to gravity and flows into the gap between the steps due to the lamination.

After that, the gel laminate 40 is returned to a temperature higher than the sol-gel transition temperature, whereby the sol-formed surface of the gel laminate 40 is gelled again. Thereby, the level | step difference between the layers by lamination can be removed.
Here, “temporary” means 5 seconds or more and 10 minutes or less, preferably 10 seconds or more and 5 minutes or less. The cooling temperature is 0 ° C. or higher and 5 ° C. or lower than the sol-gel transition temperature. In addition, since the laminate 40 is used as a mold, the step where the step is removed is at least the inner wall, but the step of the entire laminate 40 may be removed.
Temporary cooling may be performed during the lamination and / or after the lamination.

Next, an example of removing a step on the inner wall of the laminate 40 using cold air, such as a jet cooler using compressed air, will be described with reference to FIGS.
FIG. 4 is a diagram for explaining a process of removing the step inside the laminate 40 using cold air.
The steps between the layers are removed by the following steps.
Step A. Cold air is poured into the internal cavity 40a of the laminate 40 from above.
Step B. The temperature of the gel on the surface of the inner wall 44 of the laminate 40 is lowered and sol is formed.
Step C. The sol polymer solution flows into the step with the lower layer.
Step D. Stop the operation of flowing cold air.
Step E. The laminate 40 is heated by a heating mechanism, and the entire laminate 40 is maintained at a sol-gel transition temperature or higher.
Step F. The sol polymer solution is gelled again.
Through the above steps A to F, the step of the inner wall 44 of the laminate 40 can be removed.

  In the present embodiment, since only the surface portion of the laminate 40 is gelled, it has been found that the time for which the cold air is continuously applied in steps A to D is preferably 5 seconds or more and 10 minutes or less. Further, it was found that when the cold air was kept applied for longer than 10 minutes, the entire laminate 40 was cooled and sol was formed and the structure was destroyed. In addition, the above cooling time is an example and can be suitably determined according to the type of the polymer solution and the size of the laminate 40.

FIG. 5 is a cross-sectional view showing a state in which the step between the inner wall layers 42 has been removed by the operation from the process A to the process F.
FIG. 6 is a cross-sectional view showing a state in which the step between the layers 42 is removed when the cold air is applied not only to the inner wall 44 but also to the entire laminate 40.

Next, a method for evaluating the level difference of the mold created by the above method will be described.
The mold step evaluation method performs evaluation by calculating the step on the side surface by the method consisting of the following steps 1 to 4 with respect to the mold from which the step between the layers 42 of the entire gel laminate 40 is removed. It was. That is,
Step 1. A glass scale is applied to the side of the mold, and a photograph is taken with a digital camera from the horizontal direction.
Step 2. The photograph taken is analyzed by a computer, and the number of pixels at the depth of the concave portion of the step generated by the lamination on the side surface of the mold is measured.
Step 3. The number of pixels corresponding to 1 mm of the glass scale in the photograph taken is compared with the number of pixels of the depth of the recess, and the depth of the recess is calculated.
Step 4. Steps 2 to 3 are repeated to calculate the depth of the 10 recesses, and the average value is calculated.

Example 1
Using the poloxamer 407 aqueous solution whose concentration was adjusted to a sol-gel transition temperature of 15 ° C. by the above method, the dispenser 35 equipped with a taper-shaped polyethylene nozzle with a nozzle inner diameter of 610 μm was used to place the inner diameter on the stage 20 at 40 ° C. A cylindrical gel laminate 40 having a diameter of 18 mm, an outer diameter of 23 mm, and a height of 17 mm was formed.

In the obtained laminate 40 (the cross section of the laminate 40 is as shown in FIG. 4 and the step between the layers 42 remains), the depth of the concave portion of the step between the layers 42 caused by the lamination was 250 μm.
After forming the laminate 40, the gel laminate 40 obtained by cooling for 2 minutes using a jet cooler at 10 ° C. and removing the step between the layers 42, that is, the mold, has a recess in the step between the layers 42 caused by the lamination. The depth was 100 μm.
From the above, it was found that the step between the layers 42 of the gel laminate 40 can be removed by temporary cooling. Therefore, by performing the process of removing the step, the dimensional accuracy is improved and the mold becomes more suitable.

[Second Embodiment]
A case will be described where the sol-gel transition temperature of the polymer solution is higher than room temperature and the mold is formed by discharging the sol polymer solution.
The means for forming the mold can be broadly divided into two types: a layered manufacturing apparatus 1 and a laminate cooling means.
FIG. 7 is a diagram schematically showing an additive manufacturing apparatus 1B that performs the method for creating a mold according to the second embodiment.
The additive manufacturing apparatus 1B includes a droplet discharge mechanism 10 that discharges a polymer solution, a stage 20 that receives the discharged polymer solution, and a drive unit that relatively moves the droplet discharge unit 12 of the droplet discharge mechanism 10 and the stage 20. 30. A heating mechanism 22 that heats the discharged polymer solution on the stage 20 to be gelled is provided.
Here, the stage 20 and the drive unit 30 are the same as those in the first embodiment. The droplet discharge mechanism 10 is the same as that in the first embodiment, and an ink jet may be used.

  The heating mechanism 22 is a heater that heats the stage 20 and can maintain the temperature of the upper surface of the stage 20 at or above the sol-gel transition temperature of the polymer solution. Examples of the heating mechanism 22 include, but are not limited to, a conductive heater, a thermostatic bath, a radiant heater, a heat exchanger, and a Peltier element.

Next, a method for forming the gel laminate 40 will be described.
The gel laminate 40 is formed by the following steps 1 to 5. That is,
Step 1. A polymer solution in a sol state is discharged using a droplet discharge mechanism 10 at room temperature.
Step 2. The discharged polymer solution is heated on the stage 20 using the heating mechanism 22 and gelled.
Step 3. Using the drive unit 30, the syringe of the droplet discharge means 12 and the stage 20 are relatively moved in the horizontal direction.
Step 4. A gel layer 42 in the shape of a relative movement locus is formed on the stage 20.
Step 5. While moving the driving unit 30, the polymer solution is further discharged onto the formed gel layer 42 to overlap the gel layer 42. When the gel layer 42 is formed, a region 42 in which a gel is not formed is formed by securing a region where the polymer solution is not discharged inside the outer periphery of the layer 42.
By repeating Step 1 to Step 5, the operation of overlapping the polymer solution gel layer 42 is repeated to form a gel laminate 40 including a cavity structure.

Next, a method for removing irregularities between the layers 42 of the gel laminate 40 will be described.
It is assumed that the gel laminate 40 formed using the additive manufacturing apparatus 1 </ b> B is kept at the sol-gel transition temperature or higher on the stage 20.
Here, the surface portion of the laminate 40 is made into a sol by temporarily setting the surface of the gel laminate 40 to a sol-gel transition temperature or lower using a laminate cooling means. Due to gravity, the sol on the surface portion flows downward, and flows into the gaps between the layers 42 formed by the lamination.

Thereafter, the gel laminate 40 is returned to a temperature higher than the sol-gel transition temperature, whereby the sol-formed surface is gelled again. Thereby, the level | step difference between the layers 42 by lamination | stacking can be removed.
The cooling step is the same as in the first embodiment, but the heating mechanism 22 is used in the step of gelling the sol polymer solution again.
As in the first embodiment, as a result of the examination, the cooling time is preferably 5 seconds or more and 10 minutes or less. Furthermore, it was found that 10 seconds or more and 5 minutes or less are desirable.
The shape of the mold made of the gel having the sol-gel transition temperature formed by the above method is the same as that of the first embodiment.

(Example 2)
By using the poloxamer 407 aqueous solution whose concentration is adjusted to a sol-gel transition temperature of 25 ° C. by the above method, the dispenser 35 equipped with a stainless needle having an inner diameter of 0.61 mm is placed on the stage 20 having a heating temperature of 40 ° C. A cylindrical gel laminate 40 having an inner diameter of 18 mm, an outer diameter of 23 mm, and a height of 17 mm was formed.
The depth of the concave portion of the step between the layers 42 of the laminate 40 after removing the step between the layers 42 by cooling for 2 minutes using a 10 ° C. jet cooler was 280 μm before cooling. In addition, it became 100 micrometers after cooling.
According to the above method, it can be seen that even when the sol-gel transition temperature of the polymer solution is higher than room temperature, a mold in which the step shape between the layers 42 due to lamination is removed can be produced.

[Third Embodiment]
Next, a description will be given of a mold forming method that can be applied to the case where the sol-gel transition temperature of the polymer solution is higher than room temperature and lower than room temperature by setting the atmosphere to a temperature environment higher than the sol-gel transition temperature. In the present invention, the atmosphere represents the air around the additive manufacturing apparatus. When using a thermostat in the third and fourth embodiments, it means air whose temperature is adjusted inside the thermostat.
FIG. 8 is a diagram schematically illustrating an additive manufacturing apparatus 1 </ b> C that performs the method for creating a mold according to the third embodiment.
The additive manufacturing apparatus 1C according to the present embodiment includes a droplet discharge mechanism 10 that discharges a polymer solution, a stage 20 that landes the discharged polymer solution, a droplet discharge unit 12 and a stage 20 of the droplet discharge mechanism 10. The drive part 30 which relatively moves, and the thermostat 50 grade | etc., Are included.

The thermostat 50 is a device that keeps the temperature of the internal space constant. The set temperature of the thermostatic chamber 50 is set and maintained at a temperature equal to or higher than the sol-gel transition temperature of the polymer solution, thereby maintaining the polymer solution inside the droplet discharge means 12 and the stage 20 in a gel state.
Here, the droplet discharge mechanism 10, the stage 20, and the drive unit 30 are the same as those in the first embodiment, and at least the stage 20, the drive unit 30, and the droplet discharge unit 12 of the droplet discharge mechanism 10 are the constant temperature bath 50. This is different from the first embodiment in that it is housed inside the first embodiment.

The laminate cooling means of the additive manufacturing apparatus 1C according to the present embodiment and the means for forming the gel laminate 40 are the same as those in the first embodiment.
In this additive manufacturing apparatus 1 </ b> C, a polymer solution in a gel state maintained at a temperature equal to or higher than the sol-gel transition temperature is discharged onto the stage 20. Since the space temperature in the stage 20 and the thermostat 50 in this embodiment is higher than the sol-gel transition temperature, the discharged polymer solution maintains a gel state.
The method for removing the step between the layers 42 of the gel laminate 40 is the same as in the first or second embodiment.

(Example 3)
By using the poloxamer 407 aqueous solution whose concentration is adjusted so as to have a sol-gel transition temperature of 25 ° C. in a constant temperature bath 50 maintained at a space temperature of 40 ° C. by the above method, a tapered polyethylene nozzle having a nozzle inner diameter of 0.61 mm. A cylindrical gel laminate 40 having an inner diameter of 18 mm, an outer diameter of 23 mm, and a height of 17 mm was modeled on the stage 20 with the dispenser 35 equipped with the above.
Next, the mold obtained by cooling for 2 minutes using a jet cooler at 10 ° C. and removing the step between the layers 42 has a depth of the recess of the step between the layers 42 generated by the lamination of 250 μm before cooling. What was present was 100 μm.

In addition, when discharging in a sol state and heating the stage 20 and gelatinizing the laminated body 40 like 2nd Embodiment, the temperature of an upper layer part tends to become low compared with a lower layer part. Therefore, when the stack 40 continues to be stacked and the stack 40 becomes higher, the upper layer portion has a longer time from the discharge of the polymer solution to the gelation, and the required time for stacking one layer becomes longer. There is.
In this respect, in the third embodiment, since the atmosphere is higher than the sol-gel transition temperature of the polymer solution used, and therefore, it is discharged in a gel state regardless of the sol-gel transition temperature of the polymer solution used, Nevertheless, it is possible to form a mold having a stable lamination time.
By the above method, suitable template formation can be performed even when the sol-gel transition temperature of the polymer solution is not less than room temperature and not more than room temperature.

[Fourth Embodiment]
Next, a method for forming a mold having a shape in which the mold inlet is narrow and it is difficult to cool the inner wall after the gel is laminated will be described. The additive manufacturing apparatus 1 is the same as that of the third embodiment.
The gel is laminated in the following steps 1 to 4 to form a mold.
That is,
Step 1. One or several layers of gel are laminated on the stage 20.
FIG. 9 is a view showing a cross section of a laminate 40 obtained by laminating one or several layers of gel on the stage 20.
Step 2. The surface of the gel is cooled with cold air C, and the step between the layers 42 is removed.
FIG. 10 is a cross-sectional view of the laminate 40 showing a state in which the surface of the gel is cooled and the step between the layers 42 is removed.

Step 3. One or several layers of the gel are again laminated on the laminated gel.
FIG. 11 is a cross-sectional view of a laminate 40 showing a state in which one or several layers of gel are again laminated on the laminated gel.
Step 4. The surface in the vicinity of the uppermost step of the laminated gel is cooled, and the step between the layers 42 is removed.
FIG. 12 is a cross-sectional view of the laminate 40 showing a state in which the surface in the vicinity of the uppermost step of the laminated gel is cooled and the step between the layers 42 is removed.
The mold is created by repeating the above steps 1 to 4.

Example 4
By using the poloxamer 407 aqueous solution whose concentration was adjusted to a sol-gel transition temperature of 25 ° C. in a thermostatic chamber maintained at a space temperature of 40 ° C. by the above method, a tapered polyethylene nozzle having a nozzle inner diameter of 0.61 mm was formed. Layered modeling was performed on the stage 20 with the dispenser 35 attached. Each time the three layers were laminated, it was cooled for 30 seconds using a 10 ° C. jet cooler, and the step between the layers 42 was removed. The obtained mold was a cylindrical shape having an inner diameter of 18 mm, an outer diameter of 23 mm, and a height of 17 mm, and the depth of the concave portion of the step between the layers 42 caused by lamination was 110 μm.

  In this method, it is possible to form a mold in which the unevenness between the layers 42 has already been removed when the gel is laminated. Further, since the process of cooling the surface is always near the uppermost stage during lamination, it can be cooled regardless of the size and shape of the inlet after lamination.

Next, a method of injecting a model material solution will be described.
In a state where the mold which is the temperature-responsive hydrogel laminate 40 is maintained at a temperature equal to or higher than the sol-gel transition temperature, an uncured model material solution 49 is injected into the opening of the mold (FIG. 13).
The method for maintaining the mold at a temperature equal to or higher than the sol-gel transition temperature is the same as the means for layered modeling of the mold. Examples of the means 60 for injecting the model material solution 49 include, but are not limited to, a pipette, a dropper, a syringe, a pneumatic dispenser, and an inkjet.

Next, the model material and the curing (solidification) method will be described.
The model material is not particularly limited as long as it is a material that cures in a temperature range equal to or higher than the sol-gel transition temperature of the mold gel. The model material may have solids such as particles dispersed therein.
The method of curing the model material includes heat dissipation, UV (ultraviolet) irradiation, addition of a crosslinking agent, and the like depending on the type of the model material, but is not particularly limited. Agarose gel, carrageenan gel, gelatin gel and the like are listed as model materials that are cured by heat dissipation. These gels may be melted by heating to a melting temperature or higher, poured into a mold, and dissipated to the temperature of the mold to be gelled.
Moreover, PDMS (polydimethylsiloxane) etc. are mentioned as a model material hardened | cured by UV irradiation.
Examples of the curing method by adding a crosslinking agent include adding calcium chloride to an aqueous sodium alginate solution, adding borax to an aqueous polyvinyl alcohol solution, and the like.
A method may be used in which a crosslinking agent is added before injection and cured after the injection using a reaction of gradually curing. When water is added to and mixed with a powder called sodium alginate, a sparingly soluble calcium salt, and a chelating agent, which is called an alginate impression material, it has a characteristic of gradually hardening in a few minutes to a few dozen minutes. The model material may be cured by mixing the alginate impression material with water and immediately pouring it into the mold and leaving it for a few minutes to a few dozen minutes.
However, the present invention is a particularly effective molding method for a brittle model material, but the model material and the curing method are not particularly limited. FIG. 14 shows the model material 51 injected into the mold (laminated product 40) and cured.

Next, a method for separating the model material cast into the target shape and the mold, that is, a mold release method will be described.
Examples of the method for releasing the mold by removing the template include a dynamic removal method and a removal method using sol formation. Since the formed mold is brittle and plastic, it can be removed with tweezers or a trowel. However, a mechanical load is generated on the model material. Therefore, it is desirable to cool the mold to sol and remove it. Since the mold gel is made of a temperature-responsive sol-gel transition material, the mold is solated by cooling to a temperature below the solation temperature of the mold gel to be in a sol state 45 and flows out (FIG. 15).
Examples of the cooling means include placing in a refrigerator / freezer, leaving it to stand, placing a cooling object on a mold, and immersing in water, but there is no particular limitation as long as the mold can be cooled.
In this method, there is no mechanical load on the cast model material 51, and the mold gel structure (laminate 40) can be easily removed by outflow.

(Example 5)
Poloxamer 407 (BASF Japan Ltd., Kolliphor ™ P407) was added as a temperature-responsive hydrogel-forming polymer to pure water kept at 10 ° C. or lower using a beaker cooled with ice. An aqueous solution A dissolved by stirring was prepared. The concentration of poloxamer 407 was 25% by weight.
The aqueous solution A having a sol-gel transition temperature of 15 ° C. was heated to 37 ° C. to obtain a transparent gel.
A syringe having a volume of 10 mL was filled with 4 ° C. aqueous solution A, and a syringe nozzle (manufactured by Musashi Engineering Co., Ltd.) having a tip inner diameter of 250 μm was attached. Under a room temperature of 20 ° C., the syringe was left at room temperature for 10 minutes to gel the aqueous solution A. The syringe was pressurized using a compressed air dispenser (Musashi Engineering Co., Ltd .: ML-5000XII), and the aqueous solution A gel was discharged from the tip of the syringe nozzle.
A stage of a syringe nozzle and a PET (polyethylene terephthalate) film were laid on the lower part of the syringe nozzle, and the stage and the syringe were moved relative to each other to form an aqueous solution A gel mold on the PET film. A schematic view of the mold 70 on the PET film 60 is shown in FIG. The mold 70 had a cylindrical shape, an outer diameter of 6.0 mm, a thickness of 1.5 mm, and an overall height of 10 mm.
As a model material, an aqueous solution B in which κ-carrageenan (Sanki Co., Ltd., CSK-01) was dissolved in 70 ° C. water at a concentration of 2% by weight was prepared.
A part of the aqueous solution B was taken out and cooled to 40 ° C., and then injected into the opening of the gel structure of the aqueous solution A with a dropper, and left at room temperature for 30 minutes to gel the aqueous solution B.
The cylindrical structure D in which the mold 70 and the casting were combined was placed in a refrigerator at 4 ° C. together with the base PET film and left for 2 hours. FIG. 17 shows a schematic view of a gel casting of the aqueous solution B obtained after being taken out of the refrigerator. A cylindrical casting 80 having an outer diameter of 3 mm and a height of 10 mm was obtained.
From Example 5, it was found that the model material could be cast using a temperature-responsive hydrogel mold.

(Example 6)
Under a room temperature of 20 ° C., the aqueous solution A cooled to 10 ° C. or lower was filled into a syringe with a volume of 10 mL, and a syringe nozzle (manufactured by Musashi Engineering Co., Ltd.) having a tip inner diameter of 250 μm was attached. The syringe was allowed to stand at room temperature for 10 minutes to gel the aqueous solution A. The syringe was pressurized using a compressed air dispenser (Musashi Engineering Co., Ltd .: ML-5000XII), and the aqueous solution A gel was discharged from the tip of the syringe nozzle.
A stage of the syringe nozzle was placed under the syringe nozzle, a PET film was laid on the stage, and the stage and the syringe were moved relative to each other to form an aqueous solution A gel mold on the PET film. A schematic view of the mold 90 on the PET film 60 is shown in FIG. The mold 90 has a cylindrical and columnar shape. The outer diameter of the cylinder is 18 mm, the thickness is 3 mm, the outer diameter of the column is 6 mm, and the overall height is 10 mm.
As model materials, sodium alginate (Kimika, IL-2) 2% by weight aqueous solution, dicalcium phosphate 2% by weight aqueous solution, citric acid 4% by weight aqueous solution, polyacrylic particles having a diameter of 10 μm (Soken Chemical Co., Ltd., MX -1000) were mixed in a ratio of 5: 1: 1: 1, respectively.
The prepared aqueous solution E was immediately poured into the gap between the cylinder and the column of the gel structure of the aqueous solution A with a dropper and allowed to stand at room temperature for 15 minutes to cure the aqueous solution E.
Thereafter, the gel structure of the aqueous solution A and the cured aqueous solution E were immersed in cold water at 4 ° C. together with the PET substrate. After standing for 30 minutes, the cured structure of the aqueous solution C was taken out of the water.
FIG. 19 shows a schematic view of the resulting casting obtained by hardening the aqueous solution E.
A cylindrical structure 100 having an outer diameter of 12 mm, an inner diameter of 6 mm, and a length of 10 mm was obtained. The obtained cylindrical structure was in a form in which polyacrylic particles were dispersed in a hydrogel of alginic acid and the whole was clouded.

As mentioned above, although embodiment and the Example of this invention were described, according to this,
(1) Since a temperature-responsive hydrogel mold can be formed on demand, a brittle material can be cast on demand.
(2) Since the mold can be released simply by cooling the mold, the mold can be released without any mechanical load on the cast model material.
(3) When the particles are included in the solution of the model material, the model material in which the particles are dispersed or settled can be cast.
(4) By forming a part of the formed layer into a sol, the sol polymer solution flows between the steps between the layers, and the steps between the layers are removed. Therefore, the inside of the mold can be smoothed and a mold with good dimensional accuracy can be created.
(5) In the method for producing a mold, a mold can be formed by stacking gels by discharging a polymer solution in a gel state.
(6) Since a polymer solution in a sol state is discharged and gelates after discharge, a mold can be formed by stacking gels.
(7) During the lamination and after the completion of the lamination, the temperature for temporarily cooling the gel laminate is set to 0 ° C. or more and 5 ° C. or more lower than the sol-gel transition temperature, thereby preventing freezing. The surface can be made into a sol and the dimensional accuracy can be improved.
(8) The time for temporarily cooling the gel laminate during the lamination and after the completion of the lamination is set to 5 seconds or more and 10 minutes or less, thereby preventing the destruction of the gel laminate due to excessive cooling and the surface of the sol Dimensional accuracy can be improved.
(9) As a cooling means, use any means of applying cold air to the gel laminate, putting in a refrigerator, applying a cooled iron, and removing the laminate from the stage at room temperature. The laminate can be cooled below the sol-gel transition temperature, and the dimensional accuracy can be improved.
(10) By using the cool air of a jet cooler as a cooling means for cooling the laminate of gels, it is possible to cool even a shape in which a mold is complicated, and to improve dimensional accuracy.
(11) By heating the discharged polymer solution, the polymer solution having a sol-gel transition temperature higher than room temperature is gelled, and a gel layer can be laminated.
(12) A gel mold can be layered because of the layered modeling apparatus including a droplet mechanism, a droplet discharge unit, a stage, and a drive unit that relatively moves the droplet discharge unit and the stage. In addition, by providing the laminate cooling means, the layered and molded mold can be temporarily solated and the dimensional accuracy can be improved.

  DESCRIPTION OF SYMBOLS 1 ... Laminate shaping apparatus, 10 ... Droplet discharge mechanism, 12 ... Droplet discharge means, 20 ... Stage, 22 ... Heating mechanism, 30 ... Drive part, 35 ... Dispenser, 40 ... laminate, 42 ... layer, 50 ... constant temperature bath.

Special table 2013-542728 gazette Japanese Patent No. 5019851 Japanese Patent No. 5264103

Claims (14)

A step of discharging a polymer solution having a sol-gel transition temperature, which is solated at a temperature lower than the sol-gel transition temperature and gelled at a temperature higher than the sol-gel transition temperature, onto a stage by a droplet discharge mechanism;
Maintaining the polymer solution discharged to the stage at a temperature higher than the sol-gel transition temperature;
Relatively moving the droplet discharge mechanism and the stage to form a gel layer in the shape of the locus of relative movement on the stage;
Discharging the polymer solution further onto the gel layer by the droplet discharge mechanism;
A method for producing a mold characterized by comprising: In the manufacturing method of the casting_mold | template described in Claim 1,
A method for producing a mold, comprising the step of temporarily cooling the gel laminate during and / or after the lamination of the gel laminate. In the method for producing a mold according to claim 2,
The method for producing a mold, wherein the step of temporarily cooling the gel laminate is a step of removing a step between layers caused by lamination by forming a part of the formed layer into a sol. In the manufacturing method of the casting_mold | template described in any one of Claims 1-3,
In the step of forming a gel layer on the stage, the droplet discharge mechanism discharges a polymer solution in a gel state at a temperature equal to or higher than a sol-gel transition temperature. In the manufacturing method of the casting_mold | template described in any one of Claims 1-3,
In the step of forming the gel layer on the stage, a polymer solution in a sol state is discharged at a temperature lower than the sol-gel transition temperature, and the temperature is raised on the stage to cause gelation. How to make. In the manufacturing method of the casting_mold | template described in any one of Claims 2-4,
The cooling temperature when the gel laminate is temporarily cooled in the step of temporarily cooling the gel laminate is 0 ° C or higher and 5 ° C or lower than the sol-gel transition temperature. A method for creating a featured mold. In the manufacturing method of the casting_mold | template described in any one of Claims 2-4,
The method for producing a mold, wherein the time for temporarily cooling the gel laminate in the step of temporarily cooling the gel laminate is 5 seconds or more and 10 minutes or less. In the manufacturing method of the casting_mold | template described in any one of Claims 2-4,
In the step of temporarily cooling the gel laminate, the cooling means is any one of applying cold air, putting in a refrigerator, applying a cooled iron, and removing the laminate from the stage at room temperature. A method for producing a mold, comprising cooling a laminate of gels. In the manufacturing method of the casting_mold | template described in any one of Claims 2-4,
In the step of temporarily cooling the gel laminate, the gel laminate is cooled by cooling means comprising a jet cooler using compressed air. In the manufacturing method of the casting_mold | template described in any one of Claims 1-9,
In the step of forming a gel layer on the stage, the discharged polymer solution is heated by a heating means of any one of a conductive heater, a thermostatic bath, a radiant heater, a heat exchanger, and a Peltier element to form a gel. A method for producing a mold characterized by maintaining a gel or gel state. A mold making apparatus for forming a mold comprising a gel laminate using a polymer solution having a sol-gel transition temperature that is solated at a temperature lower than the sol-gel transition temperature and gelled at a temperature higher than the sol-gel transition temperature. Because
An additive manufacturing apparatus comprising: a droplet discharge unit that discharges the polymer solution; a stage that receives the discharged polymer solution; and a drive unit that relatively moves the droplet discharge unit and the stage;
A mold producing apparatus characterized by comprising: Injecting a solution of a model material into a mold created by the mold creation method according to any one of claims 1 to 10;
Solidifying the model material solution;
Separating the solidified model material and the mold;
A method for molding a model material, comprising: The method for molding a model material according to claim 12,
The method for molding a model material is characterized in that, in the separating step, the mold is cooled to form a sol by removing the mold and separated. In the molding method of the model material according to claim 12 or 13,
A method for molding a model material, comprising particles in the solution of the model material.

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