Patent Publication Number: US-2023144493-A1

Title: Molding method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a molding method of molding a molded object with a resin material using a three-dimensional lamination molding method. 
     BACKGROUND ART 
     Conventionally, a technique for molding a molded object using a resin material has been developed. For example, Patent Literature 1 discloses a technique related to a molding device for molding a molded object using an ultraviolet curable resin. The molding device of Patent Literature 1 is provided with a roller for flattening the ultraviolet curable resin discharged from the discharge unit. The roller rotates in a state of being in contact with the discharged layer of the ultraviolet curable resin, so that the ultraviolet curable resin on the surface of the layer is scraped off to flatten the surface. 
     Patent Literature 
     Patent Literature 1: JP-A-2016-16553 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     In a flattening step using the roller described above, flattening is executed by transferring a predetermined amount of the ultraviolet curable resin from the layer of the ultraviolet curable resin to the surface of the roller, and scraping off the ultraviolet curable resin. In a case where the transfer amount of the ultraviolet curable resin to the roller is small, there is a possibility that unevenness may remain on the surface of the layer of the ultraviolet curable resin, and the surface may not be sufficiently flattened. Therefore, a flattening technique for increasing the transfer amount of the ultraviolet curable resin to the roller is desired. 
     The present disclosure has been made in view of the above-described actual circumstances, and an object thereof is to provide a molding method capable of flattening a discharged resin material by using a roller. 
     Solution to Problem 
     In order to solve the above-described problems, a molding method according to the present disclosure includes a discharging step of discharging a resin material on a cured resin layer, a flattening step of transferring a part of the resin material discharged by the discharging step from the cured resin layer to a roller to flatten the resin material, and a curing step of irradiating the resin material flattened by the flattening step with light having a predetermined light amount to cure the resin material, and forming a new cured resin layer on the cured resin layer, in which the discharging step, the flattening step, and the curing step are repeatedly executed, and the cured resin layer is laminated, and the light amount is used in which a first contact angle of the resin material with respect to the cured resin layer is larger than a second contact angle of the resin material with respect to the roller. 
     Advantageous Effect of the Invention 
     As a result, when the discharge, flattening, and curing of the resin material are repeatedly executed, the light amount in which the first contact angle of the resin material with respect to the cured resin layer is larger than the second contact angle of the resin material with respect to the roller is used. As a result, by setting the first contact angle of the cured resin layer relatively larger than the second contact angle of the roller, the resin material is easily repelled from the cured resin layer, and the resin material is easily transferred to the roller. Accordingly, by adjusting the light amount in the curing step, the amount of transfer to the roller in the flattening step can be increased, and the resin material can be further flattened using the roller. It is possible to suppress the unevenness of the surface of the cured resin layer. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    illustrates a mounting board manufacturing apparatus. 
         FIG.  2    is a block diagram illustrating a control device. 
         FIG.  3    is a block diagram illustrating a control device. 
         FIG.  4    is a diagram illustrating a state where an ultraviolet curable resin is discharged from an ink jet head. 
         FIG.  5    is a diagram illustrating a state of being flattened by a roller. 
         FIG.  6    is a diagram illustrating a state of being irradiated with ultraviolet rays by an irradiation device. 
         FIG.  7    is a drawing illustrating a step of manufacturing a molded object. 
         FIG.  8    is a diagram illustrating a state of being flattened by the roller. 
         FIG.  9    is a graph illustrating a relationship between an integrated light amount with respect to an ultraviolet curable resin and a first contact angle. 
         FIG.  10    is a diagram for describing the outer diameter of a droplet and an outer diameter of a dropped ultraviolet curable resin. 
         FIG.  11    is a graph illustrating a relationship between the integrated light amount with respect to the ultraviolet curable resin and the size of an unevenness formed on a surface of the cured resin layer after the semi-curing. 
         FIG.  12    illustrates a step after the manufacturing step illustrated in  FIG.  7   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (Configuration of Mounting Board Manufacturing Apparatus) 
     Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings.  FIG.  1    illustrates mounting board manufacturing apparatus  10 . Mounting board manufacturing apparatus  10  is provided with conveyance device  20 , first molding unit  22 , second molding unit  24 , mounting unit  26 , third molding unit  29 , and control device  27  (refer to  FIGS.  2  and  3   ). Conveyance device  20 , first molding unit  22 , second molding unit  24 , mounting unit  26 , and third molding unit  29  are disposed on base  28  of mounting board manufacturing apparatus  10 . Base  28  has normally rectangular in a plan view. In the following description, a longitudinal direction of base  28  will be referred to as an X-axis direction, a shorter direction of base  28  will be referred to as a Y-axis direction, and a direction orthogonal to both the X-axis direction and the Y-axis direction will be referred to as a Z-axis direction. 
     Conveyance device  20  is provided with X-axis slide mechanism  30  and Y-axis slide mechanism  32 . X-axis slide mechanism  30  includes X-axis slide rail  34  and X-axis slider  36 . X-axis slide rail  34  is disposed to extend in the X-axis direction on base  28 . X-axis slider  36  is held by X-axis slide rail  34  to be slidable in the X-axis direction. Furthermore, X-axis slide mechanism  30  includes electromagnetic motor  38  (refer to  FIG.  2   ) and moves X-axis slider  36  to any position in the X-axis direction by driving electromagnetic motor  38 . In addition, Y-axis slide mechanism  32  includes Y-axis slide rail  50  and stage  52 . Y-axis slide rail  50  is disposed to extend in the Y-axis direction on base  28 . One end portion of Y-axis slide rail  50  is connected to X-axis slider  36 . Therefore, Y-axis slide rail  50  is movable in the X-axis direction. Stage  52  is held by Y-axis slide rail  50  so as to be slidable in the Y-axis direction. Y-axis slide mechanism  32  includes electromagnetic motor  56  (refer to  FIG.  2   ) and moves stage  52  to any position in the Y-axis direction by driving electromagnetic motor  56 . As a result, by driving X-axis slide mechanism  30  and Y-axis slide mechanism  32 , stage  52  is moved to any position on base  28 . 
     Stage  52  includes base plate  60 , holding device  62 , and lifting and lowering device  64 . Base plate  60  is formed in a flat plate shape, and base material  70  is placed on an upper surface thereof. Holding device  62  is provided on both side portions of base plate  60  in the X-axis direction. Holding device  62  fixedly holds base material  70  with respect to base plate  60  by interposing both edge portions in the X-axis direction of base material  70  placed on base plate  60 . In addition, lifting and lowering device  64  is disposed below base plate  60 , and lifts and lowers base plate  60  in the Z-axis direction. 
     First molding unit  22  is a unit for molding wiring on base material  70  placed on base plate  60  of stage  52 , and includes first printing section  72  and firing section  74 . First printing section  72  has ink jet head  76  (refer to  FIG.  2   ) and linearly discharges conductive ink on base material  70  placed on base plate  60 . The conductive ink is an example of a fluid containing metal particles of the present disclosure. The conductive ink includes, for example, fine particles of metal (such as silver) having a nanometer size as the main component dispersed in a solvent, and is cured by firing with heat. The conductive ink includes, for example, metal nanoparticles having a size of several hundred nanometers or less. The surface of the metal nanoparticle is coated with, for example, a dispersant to suppress aggregation in the solvent. 
     Ink jet head  76  discharges conductive ink from multiple nozzles, for example, by a piezo method using piezoelectric elements. In addition, the device for discharging conductive ink (fluid containing metal nanoparticles) is not limited to an ink jet head including multiple nozzles, and may be a dispenser including one nozzle, for example. In addition, the type of metal nanoparticles included in the conductive ink is not limited to silver, and may be copper, gold, or the like. In addition, the number of types of metal nanoparticles included in the conductive ink is not limited to one type, and may be multiple types. 
     Firing section  74  includes irradiation device  78  (refer to  FIG.  2   ). Irradiation device  78  is provided with, for example, an infrared heater that heats the conductive ink discharged on base material  70 . The conductive ink is fired by applying heat from an infrared heater to form wiring. The firing of the conductive ink referred to herein means, for example, a phenomenon in which by applying energy, a solvent is vaporized or a protective film of the metal nanoparticles, that is, a dispersant is decomposed, and the metal nanoparticles are brought into contact with each other or fused to increase the conductivity. The wiring can be formed by firing the conductive ink. The device for heating the conductive ink is not limited to an infrared heater. For example, mounting board manufacturing apparatus  10  may include an infrared lamp, a laser irradiation device for irradiating the conductive ink with laser light, or an electric furnace in which base material  70  from which the conductive ink is discharged is placed in a furnace and heated, as a device for heating the conductive ink. 
     In addition, second molding unit  24  is a unit for molding a resin layer on base material  70  placed on base plate  60 , and includes second printing section  84  and curing section  86 . Second printing section  84  includes ink jet head  88  (refer to  FIG.  2   ), and discharges ultraviolet curable resin  144  on base material  70  placed on base plate  60  (refer to  FIG.  4   ). Ultraviolet curable resin  144  is a resin that is cured by irradiation with ultraviolet rays. A method by which ink jet head  88  discharges ultraviolet curable resin  144  may be, for example, a piezo method using a piezoelectric element, or may be a thermal method in which a resin is heated to generate air bubbles and discharged from multiple nozzles. 
     Curing section  86  includes flattening device  90  (refer to  FIG.  2   ) and irradiation device  92  (refer to  FIG.  2   ). Flattening device  90  is a device for flattening an upper surface of ultraviolet curable resin  144  discharged on base material  70  by ink jet head  88 . For example, as illustrated in  FIG.  5   , flattening device  90  includes roller  143  and collection section  145 . Flattening device  90  scrapes off the excess resin by roller  143  while leveling the surface of ultraviolet curable resin  144 , so that the thickness of ultraviolet curable resin  144  is uniform. Roller  143  has, for example, a cylindrical shape, and moves while rotating the surface of ultraviolet curable resin  144  in a flowable state based on the control of flattening device  90  to flatten the surface. Collection section  145  has, for example, a blade protruding toward the surface of roller  143 , and stores and discharges ultraviolet curable resin  144  scraped by the blade. For example, collection section  145  discharges collected ultraviolet curable resin  144  to a waste liquid tank. Collection section  145  may return the collected ultraviolet curable resin  144  to the supply tank again. Flattening device  90  scrapes off an excess of ultraviolet curable resin  144  while leveling the surface of ultraviolet curable resin  144  to flatten the surface of ultraviolet curable resin  144 . 
     In addition, irradiation device  92  includes, for example, a mercury lamp or an LED as a light source. As illustrated in  FIG.  6   , irradiation device  92  irradiates ultraviolet curable resin  144  (refer to  FIG.  5   ) discharged on base material  70  with ultraviolet rays. As a result, ultraviolet curable resin  144  discharged on base material  70  is cured, and thin-film cured resin layer  149  can be formed. 
     Mounting unit  26  is a unit for disposing an electronic component on base material  70  placed on base plate  60 , and includes supply section  100  and mounting section  102 . Supply section  100  includes multiple tape feeders  110  (refer to  FIG.  2   ) for feeding the taped electronic components one by one, and supplies the electronic components at each supply position. The electronic component is, for example, a sensor element such as a temperature sensor. The supply of the electronic components is not limited to the supply by tape feeder  110 , and may be performed by a tray. 
     Mounting section  102  includes mounting head  112  (refer to  FIG.  2   ) and moving device  114  (refer to  FIG.  2   ). Mounting head  112  includes a suction nozzle for picking up and holding an electronic component. The suction nozzle picks up and holds the electronic component by suction of air by supplying a negative pressure from a positive and negative pressure supply device (not illustrated). The electronic component is separated by supplying a slight positive pressure from the positive and negative pressure supply device. In addition, moving device  114  moves mounting head  112  between the supply position of tape feeder  110  and base material  70  placed on base plate  60 . As a result, mounting section  102  holds the electronic component by the suction nozzle, and disposes the electronic component held by the suction nozzle on base material  70 . 
     Third molding unit  29  is a unit for applying a conductive paste on base material  70  placed on base plate  60 . The conductive paste is, for example, a viscous fluid in which micro-sized metal particles (for example, micro filler) are included in an adhesive made of resin. The micro-sized metal microparticles are, for example, metal in a flake state (silver or the like). The metal microparticles are not limited to silver, and may be gold, copper, or the like, or multiple types of metals. The adhesive contains, for example, an epoxy resin as the main component. The conductive paste is cured by heating, and is used, for example, to form a connection terminal to be connected to the wiring. The connection terminal is, for example, a bump connected to a component terminal of an electronic component, an external electrode connected to an external device, or the like. 
     Third molding unit  29  includes dispenser  130  as a device for applying a conductive paste. The device for applying the conductive paste is not limited to the dispenser, and may be a screen printing device or a gravure printing device. In addition, In the present disclosure, the term “applying” is a concept including an operation of discharging a fluid from a nozzle or the like, an operation of adhering a fluid on a target object by screen printing or gravure printing, an operation of applying a fluid with a pin, and the like. Dispenser  130  discharges the conductive paste on base material  70  or the resin layer. The discharged conductive paste is heated and cured by, for example, firing section  74  of first molding unit  22  to form a connection terminal (external electrode or the like). 
     Here, the conductive paste includes, for example, metal microparticles having a size of several tens of micrometers or less. The adhesive (resin or the like) is cured by heating, and the conductive paste is cured in a state where the metals in a flake state are in contact with each other. As described above, the conductive ink is, for example, metal integrated by fusing the metal nanoparticles by heating, and the conductivity is increased as compared with a state where the metal nanoparticles are merely in contact with each other. On the other hand, the conductive paste is cured by bringing micro-sized metal microparticles into contact with each other by curing an adhesive. Therefore, the resistance (electrical resistivity) of the wiring formed by curing the conductive ink is significantly low, for example, several to several tens of micro Ω·cm, and is lower than the resistance (several tens to several thousands of micro Ω·cm) of the wiring in which the conductive paste is cured. Accordingly, the conductive ink is suitable for molding a molded object requiring a low resistance value, such as circuit wiring having a low resistance. 
     On the other hand, the conductive paste can improve the adhesion with another member by curing the adhesive when curing, and is excellent in the adhesion with another member as compared with the conductive ink. Another member referred to herein is a member to which a conductive paste is adhered by discharging or the like, and is, for example, a resin layer, wiring, a component terminal of an electronic component, or the like. Accordingly, the conductive paste is suitable for molding a molded object requiring mechanical strength (tensile strength or the like), such as a connection terminal for fixing an electronic component to a resin layer. In mounting board manufacturing apparatus  10  of the present embodiment, a mounting board having improved electrical properties and mechanical properties can be manufactured by selectively using such a conductive ink and a conductive paste to utilize the characteristics. 
     Next, a configuration of control device  27  of mounting board manufacturing apparatus  10  will be described. As illustrated in  FIGS.  2  and  3   , control device  27  is provided with controller  120 , multiple drive circuits  122 , and storage device  124 . Multiple drive circuits  122  are connected to electromagnetic motors  38  and  56 , holding device  62 , lifting and lowering device  64 , ink jet head  76 , irradiation device  78 , ink jet head  88 , flattening device  90 , irradiation device  92 , tape feeder  110 , mounting head  112 , and moving device  114  (refer to  FIG.  2   ). Furthermore, drive circuit  122  is connected to third molding unit  29  (refer to  FIG.  3   ). 
     Controller  120  is provided with CPU, ROM, RAM, and the like, is mainly a computer, and is connected to multiple drive circuits  122 . Storage device  124  is provided with RAM, ROM, a hard disk, and the like, and stores control program  126  for controlling mounting board manufacturing apparatus  10 . Controller  120  can control the operations of conveyance device  20 , first molding unit  22 , second molding unit  24 , mounting unit  26 , third molding unit  29 , and the like by executing control program  126  with CPU. In the following description, the fact that controller  120  executes control program  126  to control each device may be simply referred to as a “device”. For example, the fact that “controller  120  causes stage  52  to move” means that “controller  120  executes control program  126 , controls the operation of conveyance device  20  through drive circuit  122 , and causes stage  52  to move by the operation of conveyance device  20 ”. 
     (Operation of Mounting Board Manufacturing Apparatus) 
     Mounting board manufacturing apparatus  10  of the present embodiment manufactures molded object  157  (refer to  FIG.  7   ) in which multiple cured resin layers  149  are laminated by the above-described configuration. For example, in control program  126  of storage device  124 , three-dimensional data of each layer obtained by slicing molded object  157  at completion is set. Controller  120  controls first molding unit  22  and the like based on the data of control program  126  to discharge, cure, and the like ultraviolet curable resin  144  to form molded object  157 . 
     First, when base material  70  is set on base plate  60  of stage  52 , controller  120  molds molded object  157  on base material  70  while moving stage  52 . As illustrated in  FIG.  4   , release film  151  which can be released by heat, for example, is adhered to the upper surface of base material  70 , and molded object  157  is formed on release film  151 . Release film  151  is released from base material  70  together with molded object  157  by heating. A method of separating base material  70  and molded object  157  is not limited to a method using release film  151 . For example, a member (support material or the like) that is melted by heat may be disposed between base material  70  and molded object  157 , and may be melted and separated. In addition, molded object  157  may be directly molded on base material  70  without using a separating member such as release film  151 . 
     When base material  70  is set, controller  120  forms cured resin layer  149  on release film  151  as illustrated in  FIG.  6   . Controller  120  molds molded object  157  having a predetermined shape by laminating multiple cured resin layers  149 . For example, controller  120  discharges, cures, or the like ultraviolet curable resin  144  based on the three-dimensional data of control program  126  to form cured resin layer  149 . 
       FIG.  7    illustrates a step of manufacturing molded object  157 . First, as illustrated in step  11  in  FIG.  7    (hereinafter, simply referred to as “S”), ink jet head  88  of second printing section  84  discharges droplets of ultraviolet curable resin  144  on release film  151 . Discharged ultraviolet curable resin  144  adheres on release film  151  and spreads in a thin film shape. 
     Next, as illustrated in S 13 , controller  120  rotates roller  143  of flattening device  90  in a state of being in contact with thin-film ultraviolet curable resin  144  to perform flattening. Roller  143  scrapes up ultraviolet curable resin  144  in a flowable state while rotating. Scraped ultraviolet curable resin  144  adheres to the surface of roller  143 , is scraped by a blade (not illustrated) of collection section  145 , and is collected in collection section  145 . 
     Next, as illustrated in S 15 , irradiation device  92  irradiates ultraviolet curable resin  144  on release film  151  with ultraviolet rays to semi-cure ultraviolet curable resin  144  to form cured resin layer  149  in the semi-cured state. Controller  120  repeatedly executes the processes of S 11 , S 13 , and S 15  to laminate cured resin layer  149  in the semi-cured state. Controller  120  may not execute a flattening step S 13  every time between a discharging step S 11  and the semi-curing step S 15 . 
     The semi-cured state described above means, for example, a state where ultraviolet curable resin  144  is not completely stable at the level of physical properties, but in a case where ultraviolet curable resin  144  is discharged on cured resin layer  149  subjected to be semi-cured, ultraviolet curable resin  144  is cured to such an extent that discharged ultraviolet curable resin  144  is not mixed with cured resin layer  149  and can be laminated on cured resin layer  149  in the semi-cured state. In other words, ultraviolet curable resin  144  is cured to such an extent that cured resin layer  149  can be further laminated on cured resin layer  149  semi-cured. Controller  120  controls the intensity (intensity of light) of the ultraviolet rays irradiated from irradiation device  92  on ultraviolet curable resin  144 , the scanning speed at which the ultraviolet rays are scanned with respect to ultraviolet curable resin  144 , the number of times of scanning, and the like, thereby changing the light amount of ultraviolet rays to cause ultraviolet curable resin  144  to be in the semi-cured state. As a result, cured resin layer  149  in the semi-cured state can be laminated in the Z-axis direction. 
     Here, in the flattening step S 13 , when the transfer amount of ultraviolet curable resin  144  discharged on the surface of cured resin layer  149  to be transferred to roller  143  is small, it is not possible to sufficiently suppress the unevenness formed on the surface of cured resin layer  149  after the semi-curing. The fact that “suppressing the unevenness” as used herein means, for example, reducing the number of unevenness to be formed, reducing the difference in height of the unevenness, or the like. 
       FIG.  8    schematically illustrates a state of the flattening step by roller  143  in S 13 . Controller  120  of the present embodiment irradiates with ultraviolet rays from irradiation device  92  using the light amount in which first contact angle θ 1  of ultraviolet curable resin  144  discharged on cured resin layer  149  in S 11  with respect to cured resin layer  149  is larger than second contact angle θ 2  of ultraviolet curable resin  144  with respect to roller  143  in S 15 . 
     Specifically, the applicant has investigated the relationship between the light amount of ultraviolet rays irradiated on ultraviolet curable resin  144  and first contact angle θ 1 .  FIG.  9    illustrates the relationship between the integrated light amount with respect to ultraviolet curable resin  144  and first contact angle θ 1 . For example, the horizontal axis in  FIG.  9    indicates the integrated light amount of ultraviolet rays irradiated on flattened thin-film ultraviolet curable resin  144  in the semi-curing step S 15 , and indicates that the integrated light amount increases in the right direction. The integrated light amount is an integration of the time during which the ultraviolet rays are irradiated per unit area and the intensity of light, and is, for example, Joules (J/cm 2 ) per unit square centimeter. The integrated light amount indicates, for example, the integrated light amount of a specific wavelength band (several hundred nm) that acts on the curing of ultraviolet curable resin  144  among the wavelengths of light included in the ultraviolet rays. In addition, the vertical axis indicates first contact angle θ 1 , and indicates that the angle increases in the up direction, that is, the wettability decreases and it comes to be difficult to wet (easy to repel). 
     First contact angle θ 1  can be calculated, for example, by the formulas illustrated in the following equations 1 and 2. 
     
       
         
           
             
               
                 
                   
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     In the above equations, r is the outer diameter of the droplet of ultraviolet curable resin  144  discharged from ink jet head  88 , as illustrated in  FIG.  10   . In addition, R is the outer diameter of ultraviolet curable resin  144  after being dropped on cured resin layer  149 . A method of calculating first contact angle θ 1  is not limited to the method using the above mathematical expression. For example, first contact angle θ 1  may be calculated by analyzing an image captured of ultraviolet curable resin  144  actually dropped. 
     Graph  153  indicated by solid lines in  FIG.  9    illustrates a case where ultraviolet curable resin  144  containing a surface adjusting agent having a liquid-repellent function is used as ultraviolet curable resin  144 . As illustrated in graph  153 , in a case where ultraviolet curable resin  144  containing a material having a liquid-repellent property is used, first contact angle θ 1  increases as the integrated light amount of ultraviolet rays irradiated in the semi-curing step S 15  increases, and the state is saturated to a predetermined angle. As first contact angle θ 1  increases, ultraviolet curable resin  144  discharged on cured resin layer  149  is easily repelled from cured resin layer  149 . Accordingly, next, when the flattening step S 13  is executed, the transfer amount of ultraviolet curable resin  144  transferred from cured resin layer  149  to roller  143  can be increased. 
       FIG.  11    illustrates the relationship between the integrated light amount with respect to ultraviolet curable resin  144  and the size of the unevenness formed on the surface of cured resin layer  149  after the semi-curing. Similar to  FIG.  9   , the horizontal axis in  FIG.  11    indicates the integrated light amount of ultraviolet rays irradiated on flattened thin-film ultraviolet curable resin  144  in the semi-curing step S 15 , and indicates that the integrated light amount increases in the right direction. In addition, the vertical axis indicates a difference in height between the maximum value (most protruding position) and the minimum value (most recessed position) of the unevenness formed on the surface of cured resin layer  149 , and indicates that the difference in height of the unevenness is increased in the up direction, that is, the unevenness increases. An estimation method of the size of the unevenness is not particularly limited, but can be measured, for example, by observing the surface of cured resin layer  149  after being semi-cured with a laser microscope. 
     In the measurements of  FIGS.  9  and  11   , for example, the shape and material of roller  143 , the material of ultraviolet curable resin  144 , the amount of droplets of ultraviolet curable resin  144  to be discharged, and the like were made constant. That is, among the factors affecting the size of first contact angle θ 1  and the formation of the unevenness, a factor other than the light amount of ultraviolet rays was fixed under a certain condition. As illustrated in  FIGS.  9  and  11   , for example, by setting the integrated light amount to be first reference light amount X 1  or more, first contact angle θ 1  can be made equal to or more than a certain angle, and the size of the unevenness formed on the surface of cured resin layer  149  can be suppressed to be equal to or less than a certain size. It is considered that this is because ultraviolet curable resin  144  is easily repelled on cured resin layer  149 , second contact angle  02  is relatively reduced, and ultraviolet curable resin  144  is easily transferred from cured resin layer  149  to roller  143 . That is, it is considered that the transfer amount of ultraviolet curable resin  144  increased. The applicant confirmed that second contact angle θ 2  is reduced by several degrees to ten and several or more as compared with first contact angle θ 1  in a case where the ultraviolet rays are irradiated with first reference light amount X 1 . It was confirmed that the difference in the unevenness was reduced to approximately ten and several pin. 
     Accordingly, in the molding method of the present embodiment, in a case where ultraviolet curable resin  144  containing a material having a liquid-repellent property is used, it is preferable to set the integrated light amount to a predetermined first reference light amount X 1  or more, so that first contact angle θ 1  is larger than second contact angle θ 2 . In ultraviolet curable resin  144  containing a material having a liquid-repellent property, when the light amount in the semi-curing step S 15  is increased, the contact angle of ultraviolet curable resin  144  with respect to cured resin layer  149 , that is, first contact angle θ 1  tends to be increased (refer to graph  153  in  FIG.  9   ). Therefore, in a case where ultraviolet curable resin  144  containing a material having a liquid-repellent property is used, by setting the integrated light amount in the semi-curing step S 15  to predetermined first reference light amount X 1  or more, ultraviolet curable resin  144  can be made easier to repel from cured resin layer  149 , and the transfer amount can be further increased. 
     Although the method of changing the integrated light amount of ultraviolet rays irradiated in S 15  is not limited, for example, the integrated light amount may be changed by changing at least one of the intensity of light, the scanning speed, or the number of scans. The intensity of light is the intensity of ultraviolet rays irradiated from irradiation device  92  in S 15 . In addition, the scanning speed is the speed at which the ultraviolet rays are scanned in a case where irradiation device  92  or base material  70  is moved to move the irradiation position of the ultraviolet rays, and the ultraviolet rays are scanned with respect to ultraviolet curable resin  144  in S 15 . In addition, the number of scans is the number of scans of the ultraviolet rays with respect to ultraviolet curable resin  144  in one step S 15 . 
     As a result, by changing the intensity of light, the scanning speed, and the number of scans, the integrated light amount with respect to ultraviolet curable resin  144  can be adjusted to perform flattening. In particular, by changing only the intensity of light, it is possible to make the execution time of the semi-curing step S 15  more uniform as compared with the case where the scanning speed or the number of scans is changed. This is because in a case where the scanning speed or the number of scans is changed, the work time for irradiating ultraviolet curable resin  144  with the ultraviolet rays from irradiation device  92  changes. In other words, by changing only the intensity of light, it is possible to suppress change in the takt time of the manufacturing step including the semi-curing step. 
     On the other hand, graph  155  indicated by dashed lines in  FIG.  9    illustrates a case where ultraviolet curable resin  144  not containing a surface adjusting agent having a liquid-repellent function is used as ultraviolet curable resin  144 . As illustrated in graph  155 , in a case where ultraviolet curable resin  144  not containing a material having a liquid-repellent property is used, first contact angle θ 1  tends to decrease as the integrated light amount of ultraviolet rays irradiated in the semi-curing step is increased, contrary to graph  153  (with the material having a liquid-repellent property). 
     Accordingly, in ultraviolet curable resin  144  not containing a material having a liquid-repellent property, the more the curing proceeds, the smaller first contact angle θ 1  of ultraviolet curable resin  144  with respect to cured resin layer  149 . In a case where ultraviolet curable resin  144  not containing a material having a liquid-repellent property is used, for example, it is preferable to irradiate with ultraviolet rays having an integrated light amount equal to or less than second reference light amount X 2 . As a result, by setting the integrated light amount in the semi-curing step to be predetermined second reference light amount X 2  or less, it is possible to suppress the decrease of first contact angle θ 1  and increase the transfer amount. 
     In addition, in the semi-curing step S 15  in  FIG.  7   , cured resin layer  149  in the semi-cured state is formed without completely curing ultraviolet curable resin  144 . As a result, for example, in a case where ultraviolet curable resin  144  is discharged on cured resin layer  149  subjected to be semi-cured, cured resin layer  149  is semi-cured to such an extent that discharged ultraviolet curable resin  144  is not mixed with cured resin layer  149  and ultraviolet curable resin  144  can be laminated on cured resin layer  149  in the semi-cured state. As a result, cured resin layer  149  in the semi-cured state can be laminated. On the other hand, when ultraviolet curable resin  144  is completely cured until the physical properties are stabilized, the execution time of one step illustrated in S 15  (irradiation time of ultraviolet rays or the like) increases, resulting in a delay in the manufacturing time of molded object  157 . On the other hand, in the molding method, the execution time of step S 15  can be shortened by semi-curing to an extent that can be laminated. By finally and completely curing laminated cured resin layer  149 , it is possible to shorten the manufacturing time of molded object  157  while achieving flattening. 
     As illustrated in  FIG.  7   , controller  120  repeatedly executes the steps S 11 , S 13 , and S 15 , laminates cured resin layer  149  in the semi-cured state, and then executes the main curing step of completely curing the laminated cured resin layer  149  (S 17 ). Controller  120  increases the integrated light amount as compared with S 15  to execute the curing of cured resin layer  149 . For example, controller  120  causes the intensity of the ultraviolet rays of S 17  larger than the intensity of the ultraviolet rays of S 15 . As a result, it is possible to mold molded object  157  that is completely stable at the level of physical properties and cured to such an extent that the droplets of ultraviolet curable resin  144  do not mix. As described above, the transfer amount of S 13  is increased, cured resin layer  149  having a small unevenness on the surface can be laminated, and cured resin layer  149  can be laminated with high accuracy. In addition, the unevenness of the surface of final molded object  157  can be reduced to, for example, approximately ten and several μm. The semi-curing step S 15  immediately before the main curing step S 17  is executed may be omitted. That is, last S 15  may be included in S 17  and executed. 
     The structure, manufacturing procedure, and the like of molded object  157  described above are examples. In the following description, as another example of molded object  157 , a case where wirings or the like are formed on a surface flattened by roller  143  will be described.  FIG.  12    illustrates an example of a manufacturing step after that of  FIG.  7   . As illustrated in  FIG.  12   , for example, after executing the flattening step S 13 , controller  120  executes the semi-curing step S 15  or the main curing step S 17 . 
     Here, as illustrated in S 15  (or S 17 ) in  FIG.  12   , on upper surface  149 A of cured resin layer  149  semi-cured, there is a possibility that uneven portions  149 B caused by the curved surface shape of the droplets are formed. The difference in the height of uneven portions  149 B may be, for example, the size less than several tens (or 20) μm, and there is a limit to the transfer of the liquid by roller  143  alone. Therefore, even when cured resin layer  149  flattened by adjusting the integrated light amount of ultraviolet rays is laminated, it may be difficult to flatten the surface of final molded object  157  (refer to  FIG.  7   ) to a fine unevenness. 
     Therefore, as illustrated in S 19 , controller  120  discharges ultraviolet curable resin  144  from ink jet head  88  on upper surface  149 A of cured resin layer  149  semi-cured in S 15  or mainly cured in S 17 . Ultraviolet curable resin  144  discharged on upper surface  149 A of cured resin layer  149  forms a thin film layer spread in a thin film shape on upper surface  149 A. The thin film layer is formed, for example, by setting a minimum discharge amount at which ultraviolet curable resin  144  can be discharged by ink jet head  88  in the discharging step S 19 , and scanning upper surface  149 A only once. For example, the thin film layer is preferably the thinnest thickness that can be formed in ink jet head  88 . Ultraviolet curable resin  144  spread in a thin film shape adheres to upper surface  149 A and then enters uneven portion  149 B. 
     Next, as illustrated in S 21 , controller  120  irradiates toward upper surface  149 A from which ultraviolet curable resin  144  is discharged with ultraviolet rays by irradiation device  92 , and discharged ultraviolet curable resin  144  is semi-cured. The semi-cured state in S 21  is a semi-cured state having higher fluidity than the semi-cured state in S 15  described above. For example, the semi-cured state of S 19  is a gel-like state where the viscosity is increased from the state of droplets at discharging to fluid. Controller  120  reduces, for example, the intensity, the number of scans, the scanning speed, the scanning time, and the like of the ultraviolet rays irradiated on ultraviolet curable resin  144  as compared with S 15 , thereby causing ultraviolet curable resin  144  to be in a semi-cured state where the fluidity is enhanced than the state of S 15 . 
     Ultraviolet curable resin  144  enters uneven portion  149 B while changing the viscosity by irradiating with ultraviolet rays. Controller  120  repeatedly executes the steps S 19  and S 21 . As a result, ultraviolet curable resin  144  spreads so as to close uneven portion  149 B to be semi-cured. On upper surface  149 A, smooth surface  149 C that is flatter than the surface of molded object  157  formed in S 11 , S 13 , S 15 , and S 17  is formed. The applicant has confirmed that by forming smooth surface  149 C, the height of the unevenness of upper surface  149 A of cured resin layer  149  is improved to several μm. By forming such smooth surface  149 C, wirings having a more uniform thickness can be formed on cured resin layer  149 . 
     For example, as illustrated in S 23 , controller  120  causes the integrated light amount larger than that of S 21  to mainly cure cured resin layer  149  having smooth surface  149 C. Next, as illustrated in S 25 , wiring  161  is formed on smooth surface  149 C cured in S 23 . Controller  120  forms wiring  161  having a desired wiring pattern, for example, by discharging conductive ink from ink jet head  76  (refer to  FIG.  2   ) of first molding unit  22  to smooth surface  149 C, and curing the conductive ink by irradiation device  78 . 
     Accordingly, controller  120  repeatedly executes steps S 11 , S 13 , and S 15 , and executes step S 19  of discharging ultraviolet curable resin  144  on laminated cured resin layer  149 . Next, controller  120  executes step S 21  of irradiating ultraviolet curable resin  144  discharged in S 19  with light having the light amount smaller than the light amount of the semi-curing step S 15  to cure ultraviolet curable resin  144  without being flattened by roller  143 , and forming smooth surface  149 C on cured resin layer  149 . 
     As described above, fine uneven portions  149 B that cannot be eliminated by roller  143  may be formed on upper surface  149 A flattened by roller  143 . Therefore, ultraviolet curable resin  144  is discharged on cured resin layer  149 , and discharged ultraviolet curable resin  144  is cured without being flattened. In addition, ultraviolet curable resin  144  is semi-cured by irradiating with light having the light amount smaller than the light amount of S 15 . As a result, ultraviolet curable resin  144  discharged on cured resin layer  149  enters fine uneven portion  149 B formed on upper surface  149 A of cured resin layer  149  by the leveling effect, spreads and is smoothed (fills uneven portion  149 B), and forms, for example, smooth surface  149 C having a surface unevenness of ±1 μm or less. It is possible to further suppress the unevenness of the surface of cured resin layer  149 . Therefore, the light amount smaller than the light amount of S 15  described above is, for example, not the light amount that is semi-cured to the extent that the cured resin layer  149  semi-cured such as S 15  can be laminated, and is the light amount such that the droplets of cured resin layer  149  discharged onto cured resin layer  149  can enter (mix) uneven portion  149 B of cured resin layer  149  and exert a leveling effect. 
     Controller  120  executes a step of discharging conductive ink on smooth surface  149 C, and a step of curing the discharged conductive ink to form wiring  161  on smooth surface  149 C (S 25 ). When the unevenness occurs on cured resin layer  149 , in a case where wiring  161  is formed on cured resin layer  149  by a three-dimensional lamination molding method, there is a possibility that the thickness of wiring  161  may be uneven or wiring  161  may be disconnected. In other words, a connection failure occurs. On the other hand, by discharging conductive ink on smooth surface  149 C formed on cured resin layer  149  and curing the conductive ink, it is possible to form wiring  161  having a more uniform thickness (having higher electrical characteristics) on the cured resin layer. 
     Furthermore, as illustrated in S 25 , controller  120  may form bump  163  on wiring  161  to mount electronic component  165 . Specifically, after forming wiring  161 , controller  120  controls third molding unit  29  to discharge the conductive paste on wiring  161  by dispenser  130 . Controller  120  discharges the conductive paste in accordance with a position connected to component terminal  167  of wiring  161  (position of bump  163 ). 
     Next, controller  120  moves stage  52  below mounting unit  26 , and mounts electronic component  165  by mounting section  102 . Mounting head  112  (refer to  FIG.  2   ) of mounting section  102  picks up and holds electronic component  165  by the suction nozzle, and disposes component terminal  167  of electronic component  165  so as to be located at the positions of the conductive paste. Controller  120  heats and cures the conductive paste by firing section  74  of first molding unit  22  to form bump  163 . As a result, component terminal  167  of electronic component  165  is electrically connected to wiring  161  via bump  163 . In this manner, mounting board manufacturing apparatus  10  of the present embodiment can execute flattening and smoothing upper surface  149 A of cured resin layer  149 , and can manufacture a mounting board on which electronic component  165  is mounted on smooth surface  149 C. 
     Incidentally, in the above example, ultraviolet curable resin  144  is an example of a resin material. Step of S 11  is an example of a discharging step. Step of S 13  is an example of a flattening step. Step of S 15  is an example of a curing step. Step of S 19  is an example of a second discharging step. Step of S 21  is an example of a second curing step. Step of S 25  is an example of a third discharging step and a third curing step. 
     Hereinbefore, according to the present embodiment described above, the following effects are obtained. The molding method of the present embodiment includes the step S 11  of discharging ultraviolet curable resin  144  on cured resin layer  149 , and the step S 13  of transferring a part of ultraviolet curable resin  144  discharged in S 11  from cured resin layer  149  to roller  143  to flatten ultraviolet curable resin  144 . In addition, the molding method includes the step S 15  of irradiating ultraviolet curable resin  144  flattened in S 13  with ultraviolet rays having a predetermined integrated light amount to cure ultraviolet curable resin  144 , and forming new cured resin layer  149  on cured resin layer  149 , and repeatedly executes S 11 , S 13 , and S 15  to laminate cured resin layer  149 . In S 15 , controller  120  uses an integrated light amount in which first contact angle θ 1  of ultraviolet curable resin  144  with respect to cured resin layer  149  is larger than second contact angle θ 2  of ultraviolet curable resin  144  with respect to roller  143 . 
     As a result, by making first contact angle θ 1  of cured resin layer  149  relatively larger than second contact angle θ 2  of roller  143 , ultraviolet curable resin  144  is easily repelled from cured resin layer  149 , and is easily transferred to roller  143 . Accordingly, by adjusting the integrated light amount in S 15 , the amount of transfer to roller  143  in S 13  can be increased, and ultraviolet curable resin  144  can be further flattened by using roller  143 . It is possible to suppress the unevenness of upper surface  149 A of cured resin layer  149 . The fact that “suppressing the unevenness” means, for example, reducing the number of unevenness, reducing the difference in height of the unevenness, or the like. 
     The present disclosure is not limited to the above-described examples, but can be performed in various forms in which various modifications and improvements are made based on the knowledge of those skilled in the art. For example, in the above example, the ultraviolet curable resin cured by irradiation with ultraviolet rays is adopted as the resin material of the present disclosure, but the present disclosure is not limited thereto. For example, the resin material can adopt various curable resins such as a thermosetting resin cured by heat. In this case, in a case where the thermosetting resin is heated by an infrared heater or the like, flattening can be achieved by adjusting the light amount (infrared light or the like) irradiated from a heat source to be heated in the same manner as ultraviolet rays. In addition, the light amount in the present disclosure is not limited to the integrated light amount per unit area, but may be the light amount irradiated to ultraviolet curable resin  144  per unit time in step S 15 . In addition, controller  120  may not execute the manufacturing step in  FIG.  12   . Accordingly, controller  120  may not form wiring  161  or the like on cured resin layer  149  and may not mount electronic component  165 . In addition, the three-dimensional lamination molding method in the present disclosure is not limited to an ink jet method or a stereo lithography method (SL), and other methods such as, for example, a fused deposition molding (FDM) method can be employed. 
     REFERENCE SIGNS LIST 
       143 : roller,  144 : ultraviolet curable resin (resin material),  149 : cured resin layer,  149 C: smooth surface,  161 : wiring (conductor), X 1 : first reference light amount (reference light amount), X 2 : second reference light amount (reference light amount), θ 1 : first contact angle, θ 2 : second contact angle.