Method of fabricating shaped object and forming apparatus

Patent metadata

Field	Value
Publication number	US-11524456-B2
Application number	US-202016879835-A
Country	US
Kind code	B2
Filing date	May 21, 2020
Priority date	Jun 14, 2019
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A method of fabricating a shaped object includes: preparing a formation sheet including a base and a thermally expansive layer stacked on a first main surface of the base, the thermally expansive layer including a binder and thermally expandable material; heating the base of the formation sheet to a temperature lower than an expansion initiation temperature at which the thermally expandable material starts to expand; and heating the thermally expansive layer of the formation sheet after heating of the base, to a temperature higher than or equal to the expansion initiation temperature at which the thermally expandable material starts to expand, thereby causing expansion of the thermally expansive layer.

First claim

What is claimed is:

1. A method of fabricating a shaped object, the method comprising:
preparing a formation sheet comprising a base and a thermally expansive layer stacked on a first main surface of the base, the thermally expansive layer including a binder and thermally expandable material;
performing a base heating process comprising heating the base of the formation sheet to a temperature lower than an expansion initiation temperature at which the thermally expandable material starts to expand; and
performing an expansion process comprising heating the thermally expansive layer of the formation sheet after heating of the base, to a temperature higher than or equal to the expansion initiation temperature at which the thermally expandable material starts to expand, thereby causing expansion of the thermally expansive layer,
wherein:
in the base heating process, said heating the base of the formation sheet comprises heating a first area of the base to a first temperature lower than the expansion initiation temperature and heating a second area of the base to a second temperature lower than the expansion initiation temperature, wherein the first temperature is lower than the second temperature, whereby, in the expansion process, expansion of a third area of the thermally expansive layer corresponding to the first area of the base requires an amount of heat larger than an amount of heat for expansion of a fourth area of the thermally expansive layer corresponding to the second area of the base, and
the expansion process is performed after said heating the first area of the base to the first temperature and said heating the second area of the base to the second temperature in the base heating process, thereby causing a protrusion in the third area of the thermally expansive layer after expansion to have an inclination angle smaller than an inclination angle of a protrusion in the fourth area of the thermally expansive layer after expansion, and
the base heating process and the expansion process are performed such that the protrusion formed in the third area of the thermally expansive layer expanded in the expansion process and the protrusion formed in the fourth area of the thermally expansive layer expanded in the expansion process have substantially a same height as each other above the base.

2. The method of fabricating the shaped object according to claim 1 , further comprising:
stacking a thermal conversion layer on the thermally expansive layer or a second main surface of the base opposite to the first main surface, the thermal conversion layer converting electromagnetic waves into heat,
wherein the electromagnetic waves are emitted to the thermal conversion layer in the expansion process.

3. The method of fabricating the shaped object according to claim 1 , wherein the base is heated by a heater in the base heating process.

4. The method of fabricating the shaped object according to claim 1 , wherein the inclination angle of each of the protrusions on the thermally expansive layer after expansion is adjusted by controlling, in the base heating process, a difference of a temperature of the heated base from the expansion initiation temperature at which the thermally expandable material starts to expand.

5. The method of fabricating the shaped object according to claim 1 , wherein:
the base is heated by a heater in the base heating process, and
the thermally expansive layer is heated by being irradiated with a laser beam in the expansion process.

6. The method of fabricating the shaped object according to claim 1 , wherein, in the base heating process, the base is heated to a temperature 5° C. or more lower than the expansion initiation temperature at which the thermally expandable material starts to expand in the expansion process.

7. A forming apparatus for fabricating a shaped object from a formation sheet including a base and a thermally expansive layer stacked on a first main surface of the base, the thermally expansive layer including a binder and thermally expandable material, the forming apparatus comprising:
a heating unit configured to perform a base heating process comprising heating the base of the formation sheet to a temperature lower than an expansion initiation temperature at which the thermally expandable material starts to expand; and
an expanding unit configured to perform an expansion process comprising heating the thermally expansive layer of the formation sheet to a temperature higher than or equal to the expansion initiation temperature at which the thermally expandable material starts to expand, thereby causing expansion of the thermally expansive layer,
wherein:
in heating the base of the formation sheet in the base heating process, the heating unit is configured to heat a first area of the base to a first temperature lower than the expansion initiation temperature and heat a second area of the base to a second temperature lower than the expansion initiation temperature, wherein the first temperature is lower than the second temperature, whereby, in the expansion process performed by the expanding unit, expansion of a third area of the thermally expansive layer corresponding to the first area of the base requires an amount of heat larger than an amount of heat for expansion of a fourth area of the thermally expansive layer corresponding to the second area of the base, and
the expanding unit is configured to perform the expansion process after said heating the first area of the base to the first temperature and said heating the second area of the base to the second temperature in the base heating process performed by the heating unit, thereby causing a protrusion in the third area of the thermally expansive layer after expansion to have an inclination angle smaller than an inclination angle of a protrusion in the fourth area of the thermally expansive layer after expansion, and
wherein the heating unit is configured to perform the base heating process and the expansion unit is configured to perform the expansion process such that the protrusion formed in the third area of the thermally expansive layer expanded in the expansion process and the protrusion formed in the fourth area of the thermally expansive layer expanded in the expansion process have substantially a same height as each other above the base.

8. The forming apparatus according to claim 7 , wherein
the formation sheet further includes a thermal conversion layer on the thermally expansive layer or a second main surface of the base opposite to the first main surface, the thermal conversion layer converting electromagnetic waves into heat, and
the expanding unit emits the electromagnetic waves to the thermal conversion layer.

9. The forming apparatus according to claim 7 , further comprising:
conveyance rollers configured to convey the formation sheet along a conveyance path, wherein
the heating unit comprises a heater,
the expanding unit comprises a lamp, and
the heater and the lamp are disposed along the conveyance path in order of the heater and the lamp from an upstream side to a downstream side of the conveyance path.

10. The forming apparatus according to claim 7 , wherein, in the base heating process, the heating unit heats the base to a temperature 5° C. or more lower than the expansion initiation temperature at which the thermally expandable material starts to expand.

Assignees

• Casio Computer Co Ltd

Inventors

• Horiuchi Yuji

Classifications

• B29C64/268 Primary

  using laser beams; using electron beams [EB] · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• B41M5/26

  Thermography (B41M5/20, B41M5/24 take precedence); {Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used (B23K takes precedence; thermographic or photothermographic systems using noble metal compounds G03C1/494)} · CPC title

• B29C59/043 Primary

  for profiled articles · CPC title

• B29C2035/0838

  using laser · CPC title