U.S. patent application number 17/320341 was filed with the patent office on 2021-09-02 for method for casting a construction element.
The applicant listed for this patent is LAING O'ROURKE AUSTRALIA PTY LIMITED. Invention is credited to James Bruce Gardiner, Steven Robert Janssen.
Application Number | 20210268690 17/320341 |
Document ID | / |
Family ID | 1000005583550 |
Filed Date | 2021-09-02 |
United States Patent
Application |
20210268690 |
Kind Code |
A1 |
Gardiner; James Bruce ; et
al. |
September 2, 2021 |
Method for Casting a Construction Element
Abstract
The present invention relates to a method for casting building
material to form a construction element using a computer-controlled
apparatus. The method comprises the steps of: moving the material
deposition head and selectively depositing material, to fabricate a
formwork; pouring building material in contact with at least a
portion of the formwork; at least partially curing the building
material, thereby forming the construction element; and removing at
least a portion of the formwork from the construction element.
Inventors: |
Gardiner; James Bruce;
(Chippendale, AU) ; Janssen; Steven Robert;
(Chippendale, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LAING O'ROURKE AUSTRALIA PTY LIMITED |
North Sydney |
|
AU |
|
|
Family ID: |
1000005583550 |
Appl. No.: |
17/320341 |
Filed: |
May 14, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14769151 |
Aug 20, 2015 |
11065782 |
|
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PCT/AU2014/000160 |
Feb 21, 2014 |
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17320341 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24D 3/14 20130101; B28B
23/022 20130101; B28B 7/362 20130101; B33Y 80/00 20141201; E04G
21/0463 20130101; B28B 7/346 20130101; E04B 1/3505 20130101; E04G
11/00 20130101; B33Y 10/00 20141201; B29C 64/118 20170801; Y02B
30/00 20130101; B25J 11/00 20130101; B28B 1/14 20130101; B28B 7/342
20130101 |
International
Class: |
B28B 7/34 20060101
B28B007/34; B28B 7/36 20060101 B28B007/36; B28B 23/02 20060101
B28B023/02; B25J 11/00 20060101 B25J011/00; E04G 21/04 20060101
E04G021/04; B29C 64/118 20060101 B29C064/118; B28B 1/14 20060101
B28B001/14; E04G 11/00 20060101 E04G011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 2013 |
AU |
2013900587 |
May 27, 2013 |
AU |
2013901886 |
Feb 5, 2014 |
AU |
2014900338 |
Claims
1. A method for casting building material to form a construction
element using a computer-controlled apparatus, the apparatus having
a material deposition head in communication with a reservoir of
formwork material and being movable within a build volume
responsive to computer instructions, the method comprising the
steps of: receiving, by the apparatus, computer instructions
relating to a formwork geometry; moving the material deposition
head within the build volume and selectively depositing formwork
material in specific locations to fabricate a formwork
corresponding with the formwork geometry; pouring building material
in contact with at least a portion of the formwork; at least
partially curing the building material in contact with the formwork
to form the construction element; and removing at least a portion
of the formwork from the construction element.
2. The method for casting building material to form a construction
element according to claim 1, wherein the step of removing the
formwork comprises heating the construction element and the
formwork to a temperature above the melting point of the to melt
the at least a portion of the formwork.
3. The method for casting building material to form a construction
element according to claim 2, comprising the further step of
collecting and recirculating the melted formwork material to the
reservoir.
4. The method for casting building material to form a construction
element according to claim 2, wherein the temperature is less than
70.degree. C.
5. The method for casting building material to form a construction
element according to claim 2, wherein the formwork material is a
wax compound.
6. The method for casting building material to form a construction
element according to claim 1, wherein the step of removing the
formwork comprises spraying the formwork with a liquid to dissolve
the at least a portion of the formwork.
7. The method for casting building material to form a construction
element according to claim 1, wherein the step of removing the
formwork comprises at least partially submerging the construction
element and the at least a portion of the formwork in a liquid to
dissolve the at least a portion of the formwork.
8. The method for casting building material to form a construction
element according to claim 1, further comprising the step of
selectively applying one or more materials in specific locations to
affect a surface finish of the construction element to the
formwork.
9. The method for casting building material to form a construction
element according to claim 0, wherein the one or more material
include at least one of an acid, a pigment, paint, or masking.
10. The method for casting building material to form a construction
element according to claim 1, further comprising the steps of:
before pouring the building material, selectively applying a
retarder to the formwork in specific locations; and after the at
least a portion of the formwork is removed from the construction
element, removing uncured building material from the construction
element by mechanical means.
11. The method for casting building material to form a construction
element according to claim 0, wherein the apparatus further has a
milling head movable within the build volume responsive to computer
instructions, and the method further comprises the step of, before
pouring the building material, selectively milling, by the
apparatus, the formwork in specific locations.
12. The method for casting building material to form a construction
element according to claim 1, wherein the step of moving the
material deposition head to fabricate the formwork comprises the
further sub-step of moving the material deposition head to
fabricate a scaffold structure at least partially enclosed by a
shell, the scaffold structure and shell thereby forming the
formwork.
13. The method for casting building material to form a construction
element according to claim 12, wherein the scaffold structure
comprises a network of interconnected braces.
14. The method for casting building material to form a construction
element according to claim 12, wherein the scaffold structure
defines at least one conduit arranged to allow a fluid to pass
through the formwork.
15. The method for casting building material to form a construction
element according to claim 0, wherein the step of moving the
material deposition head to fabricate the formwork comprises the
further sub-step of selectively heating or cooling at least a
portion of the build volume.
16. The method for casting building material to form a construction
element according to claim 1, further comprising the step of:
before pouring the building material, selectively applying one or
more portions of composite material to the formwork in specific
locations; such that after the at least a portion of the formwork
is removed from the construction element, the one or more portions
of composite material are secured to the construction element.
17. The method for casting building material to form a construction
element according to claim 16, further comprising the step of:
after selectively applying one or more portions of composite
material selectively to the formwork, at least partially curing the
one or more portions of composite material.
18. A method for casting building material to form a construction
element using a computer-controlled apparatus, the apparatus having
a material deposition head in communication with a reservoir of
formwork material and being movable within a build volume
responsive to computer instructions, the method comprising the
steps of: receiving, by the apparatus, computer instructions
relating to a first formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations to fabricate a first
formwork corresponding with the formwork geometry; selectively
applying one or more portions of composite material to the first
formwork in specific locations to form a homogenous layer of
composite material; curing the layer of composite material to form
a composite element; removing the first formwork from the composite
element; pouring a first building material in contact with at least
a portion of the composite element; and curing the first building
material in contact with the composite element, thereby forming a
first construction element.
19. The method for casting building material to form a construction
element according to claim 18 comprising the further steps of:
arranging a second formwork proximally to the first construction
element; pouring a second building material in contact with at
least a portion of the first construction element and the second
formwork; curing the second building material in contact with the
first construction element and the second formwork, thereby forming
a second construction element joined to the first construction
element; and removing the second formwork from both construction
elements.
20. The method for casting building material to form a construction
element according to claim 19, wherein the first and second
building materials have a substantially identical composition.
21. The method for casting building material to form a construction
element according to claim 16 wherein the one or more portions of
composite material are selectively applied to the formwork by a
computer-controlled composite lay-up head movable responsive to
computer instructions.
22. The method for casting building material to form a construction
element according to claim 16 wherein the composite material is a
preimpregnated tape.
23. A method for casting building material to form a construction
element using a computer-controlled apparatus, the apparatus having
a material deposition head in communication with a reservoir of
formwork material and being movable within a build volume
responsive to computer instructions, the method comprising the
steps of: receiving, by the apparatus, computer instructions
relating to a first formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations to fabricate a first
formwork corresponding with the first formwork geometry;
selectively applying one or more portions of composite material to
the first formwork in specific locations; curing the one or more
portions of composite material to form one or more first composite
elements; receiving, by the apparatus, computer instructions
relating to a second formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations to fabricate a second
formwork corresponding with the second formwork geometry, the
second formwork at least partially in contact with the first
formwork or the one or more first composite elements; selectively
applying one or more portions of composite material to the second
formwork in specific locations; curing the one or more portions of
composite material to form one or more second composite elements;
pouring building material in contact with at least a portion of the
first and second formworks; curing the building material in contact
with the first and second formworks, thereby forming a construction
element; and removing the first and second formworks from the
construction element.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to casting settable
building materials to form construction elements used to construct
buildings or similar structures. In particular, the invention
relates to casting building materials to form construction elements
using a mould (formwork).
BACKGROUND TO THE INVENTION
[0002] Casting of settable building materials, such as concrete, to
form elements which are used to construct buildings, or which form
an integral part of a building, has been performed for a
considerable length of time. Casting these materials typically
involves constructing a mould, commonly known as formwork, having a
cavity with inverse geometry to the desired geometry of a
construction element. Substantially liquid building material is
poured into the cavity and set (cured), solidifying the building
material within the cavity and forming a construction element
having the desired geometry. The mould is then removed from the
construction element.
[0003] One advantage of casting construction elements is the scope
for creating complex construction element geometries, allowing
elements to be cast having specific functional or aesthetic
properties. For example, as a settable building material changes
state from a liquid to a solid, the material may be poured into a
mould having an amorphous, complex shape and cured, following which
the solidified part has a substantially corresponding amorphous,
complex shape, which would be difficult to create using other
processes.
[0004] As architecture and engineering has become more
sophisticated, the need for cast, non-standard `freeform` geometry
construction elements has increased. One issue common to many
non-standard geometry structures is the presence of `undercut` or
over-hanging surfaces. If a construction element is cast having
such surfaces using a conventional, rigid formwork, when the
building material solidifies the formwork is engaged with the
construction element, proving difficult or impossible to remove the
formwork from the construction element.
[0005] Past solutions to overcome this issue have involved the use
of a complex, multi-part formwork, which may be disassembled to
release the construction element from the formwork, or a consumable
formwork which is destroyed after the construction element
solidifies to release the element, for example, by breaking the
formwork apart. However, these solutions are often expensive due to
the complexity of the multi-part formwork and/or the quantity of
formwork material consumed during each casting process, which can
create large volumes of waste formwork material, and also can
require a considerable length of time and/or energy to remove the
formwork from the cast element.
[0006] Accordingly, it would be useful to provide a more efficient,
sustainable and cost effective method for casting building material
to form a construction element, and particularly for casting a
construction element which has complex geometry, such as
over-hanging surfaces.
SUMMARY OF THE INVENTION
[0007] According to one aspect of the invention, there is provided
a method for casting building material to form a construction
element using a computer-controlled apparatus, the apparatus having
a material deposition head in communication with a reservoir of
formwork material and being movable within a build volume
responsive to computer instructions, the method comprising the
steps of: receiving, by the apparatus, computer instructions
relating to a formwork geometry; moving the material deposition
head within the build volume and selectively depositing formwork
material in specific locations, to fabricate a formwork
corresponding with the formwork geometry; pouring building material
in contact with at least a portion of the formwork; at least
partially curing the building material in contact with the
formwork, thereby forming the construction element; and removing at
least a portion of the formwork from the construction element.
[0008] Referring to another aspect of the invention, there is
provided a method for casting building material to form a
construction element using a computer-controlled apparatus, the
apparatus having a material deposition head in communication with a
reservoir of formwork material and being movable within a build
volume responsive to computer instructions, the method comprising
the steps of: receiving, by the apparatus, computer instructions
relating to a first formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations, to fabricate a first
formwork corresponding with the formwork geometry; selectively
applying one or more portions of composite material to the first
formwork, in specific locations, to form a homogenous layer of
composite material; curing the layer of composite material to form
a composite element; removing the first formwork from the composite
element; pouring a first building material in contact with at least
a portion of the composite element; and curing the first building
material in contact with the composite element, thereby forming a
first construction element.
[0009] In an alternative aspect of the invention, there is provided
a method for casting building material to form a construction
element using a computer-controlled apparatus, the apparatus having
a material deposition head in communication with a reservoir of
formwork material and being movable within a build volume
responsive to computer instructions, the method comprising the
steps of: receiving, by the apparatus, computer instructions
relating to a first formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations, to fabricate a first
formwork corresponding with the first formwork geometry;
selectively applying one or more portions of composite material to
the first formwork, in specific locations; curing the one or more
portions of composite material to form one or more first composite
elements; receiving, by the apparatus, computer instructions
relating to a second formwork geometry; moving the material
deposition head within the build volume and selectively depositing
formwork material in specific locations, to fabricate a second
formwork corresponding with the second formwork geometry, the
second formwork at least partially in contact with the first
formwork or the one or more first composite elements; selectively
applying one or more portions of composite material to the second
formwork, in specific locations; curing the one or more portions of
composite material to form one or more second composite elements;
pouring building material in contact with at least a portion of the
first and second formworks; curing the building material in contact
with the first and second formworks, thereby forming a construction
element; and removing the first and second formworks from the
construction element.
[0010] In the context of this specification, `construction element`
refers generally to any object used in conjunction with other
elements to construct a structure and in particular, refers to
elements used to construct buildings, bridges and similar
structures, such as artificial reefs, pipes or water treatment
plants. Construction elements which are attached to a larger
structure, or which form an entire, discrete structure, are
considered within the scope of `construction element`.
[0011] Throughout this specification the term `formwork` refers
generally to an article used to shape the structure of another
material during the transition of that material from a fluid or a
flexible matrix, to a substantially rigid structure. Such
`formworks` include a mould, buck, core or mandrel.
[0012] For the purposes of this specification, `composite material`
or `composite` refers generally to fibre-reinforced polymer
composite materials, including thermoplastic composites, short
fibre thermoplastics, long fibre thermoplastics and long
fibre-reinforced thermoplastics. The composite material may include
fibres formed from natural (organic) or synthetic (non-organic)
materials. In particular, this specification will make reference to
carbon-fibre or glass-fibre cloth, mat or tape and fibre
pre-impregnated (known as `pre-preg`) tape. However, the term
composite may also include reference to metal matrix or ceramic
matrix composite materials.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Preferred embodiments of the invention will now be
described, by way of example only, with reference to the
accompanying drawings in which:
[0014] FIG. 1A is a perspective view of an apparatus depositing
material to create a formwork;
[0015] FIG. 1B is a perspective view of a computer-controlled
milling spindle;
[0016] FIG. 1C is a perspective view of computer-controlled robot
arm connected to the milling spindle;
[0017] FIG. 1D is a perspective view of the computer-controlled
robot arm connected to a material deposition head;
[0018] FIG. 2 is a perspective view of a formwork and a cast
construction element;
[0019] FIG. 3 is a perspective view of an alternative cast
construction element;
[0020] FIG. 4 is a partial section view of an alternative formwork
and cast construction element;
[0021] FIG. 5 is a perspective view of a further alternative cast
construction element;
[0022] FIG. 6 is a perspective view of a reinforcement frame
assembled within a build volume;
[0023] FIG. 7A is an exploded view of a further alternative
formwork and cast construction element;
[0024] FIG. 7B is a detailed view of a further alternative cast
construction element;
[0025] FIGS. 8A and 8B are perspective views of further alternative
formworks and corresponding respective cast construction
elements;
[0026] FIG. 9 is a perspective view of an alternative cast
construction element secured to a plurality of columns;
[0027] FIG. 10 is a perspective view of an apparatus applying
composite material to different formworks;
[0028] FIG. 11 is a perspective view of two further alternative
formworks, one formwork having portions of composite material
secured thereto;
[0029] FIG. 12 is a perspective view of a further alternative
formwork covered with a composite material and joined to a further
alternative cast construction element;
[0030] FIG. 13A is a perspective view a further alternative
formwork with portions of composite material secured thereto;
[0031] FIG. 13B is a side view of two alternative cast construction
elements having integral portions of composite material;
[0032] FIGS. 14A and 14B are cross-section views of an alternative
formwork having portions of composite material secured thereto and
an alternative construction element cast using the formwork;
[0033] FIGS. 15A-15D illustrate various stages of fabricating a
further alternative formwork having multiple integral portions of
composite material; and
[0034] FIG. 15E is a cross-section view of an alternative cast
construction element having multiple integral portions of composite
material.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0035] The present disclosure generally relates to a method for
casting a settable building material, such as concrete, to form a
construction element using a mould (formwork) fabricated by a
computer-controlled apparatus responsive to computer instructions
relating to the formwork geometry. In particular, the disclosure
relates to a method for casting building material to form a
construction element using at least one meltable or dissolvable
formwork fabricated by the apparatus, where the at least one
formwork is melted or dissolved to remove the formwork from the
cured construction element, and the formwork material may be
recycled to the computer-controlled apparatus for re-use.
Furthermore, the disclosure relates to a method for casting
building material to form a construction element using a formwork
fabricated by the computer-controlled apparatus, where composite
material and/or a surface treatment, configured to affect the
construction element, is selectively applied to the formwork and
transferred to, or integrated with, the construction element during
the casting process.
[0036] In FIG. 1A, an apparatus 1 is shown depositing material to
fabricate a formwork 2. The apparatus 1 comprises a first gantry 3
and a second gantry 4, arranged perpendicular to one another and
movable in relation to each other, and an extendable arm 5
connected to a carriage 6 movable along the second gantry 4. A
material deposition head 7 is rotatably connected to an end of the
arm 5 around at least two axes. The material deposition head 7 has
one or more deposition nozzles 8 in communication with a formwork
material reservoir (not illustrated) of substantially liquid
formwork material, via a hose 9. The gantries 3, 4, carriage 6 and
arm 5 cooperate to move the material deposition head 7 within a
build volume, being a defined volume adjacent to the apparatus 1,
in this case below the gantries 3, 4. In order to allow
`construction scale` formwork to be fabricated, i.e. formwork that
is sufficiently dimensioned to allow casting of large construction
elements for buildings, the build volume is typically greater than
1 m.sup.3.
[0037] The apparatus 1 moves the material deposition head 7 within
the build volume responsive to computer instructions relating to a
formwork geometry and selectively deposits portions of formwork
material in specific locations to fabricate the formwork 2, which
corresponds with the formwork geometry. The computer instructions
relating to the formwork geometry are dependent on a digital
three-dimensional (3D) model of the construction element or
formwork created within computer aided design (CAD) software. The
3D model of the construction element of formwork is created by a
user operating the CAD software and/or by an algorithm executed by
the CAD software. Generally, the CAD data is derived as a result of
a user modelling the construction element geometry (known as a
digital `buck`) within a virtual environment in the CAD software,
and the CAD software calculating a digital `mould` geometry, being
the inverse geometry of the buck which provides the mould
(formwork) geometry necessary to cast the construction element. The
apparatus 1 is then provided with computer instructions relating to
the digital mould, directing the apparatus to fabricate the
formwork 2.
[0038] Optionally, the apparatus 1 includes a 3D scanner (not
shown), such as a near field sonar or infrared scanner, configured
to scan the geometry of the formwork 2 and verify the geometry with
the 3D model at predefined intervals during the fabrication
process. When the 3D scanner detects variation from the 3D model
beyond a predefined tolerance, computer instructions are executed
by the apparatus 1 to adjust the geometry of the formwork 2 being
fabricated to within the defined tolerance. For example, this may
involve adding or removing formwork material from the formwork 2 by
the apparatus 1.
[0039] Formwork material is typically deposited by the apparatus 1
in successive, substantially horizontal planar layers, with a first
layer being deposited on a substrate 10 and each subsequent layer
deposited at least partially in contact with the previously
deposited layer. The formwork material may also be deposited on a
variable plane or in non-planar layers, for example, in continuous
curves forming self-supporting beads of formwork material.
[0040] In scenarios when the apparatus 1 deposits successive layers
of formwork material to fabricate the formwork 2, the thickness of
the layers are typically in the region of 0.05-1 cm, to optimise
the resolution of the formwork. In some instances, the layers of
material may be thicker than this, for example, where minimising
the time required to fabricate a large formwork is a priority,
resulting in `steps` being created between layers, or other
imperfections being formed on the formwork. In such instances, the
`steps` or surface imperfections are removed by a milling
(finishing) operation. This is typically performed by the apparatus
1 operating a milling head (not shown), responsive to the computer
instructions, to selectively remove portions of formwork material
from the formwork.
[0041] The formwork material is supplied to the apparatus 1 from
the reservoir (not shown) in a substantially liquid state, having
sufficient viscosity to flow through the hose 9 to the nozzle 8.
The formwork material composition may include viscosity adjusting
agents to optimise the viscosity of the formwork material and aid
flow rate. The formwork material is preferably heated before being
deposited from the nozzle 8 to a temperature just above the melting
point of the material, preferably within a range of 0-10.degree. C.
above the melting point. Shortly after deposition, the formwork
material rapidly cools and hardens, at least partially solidifying.
The formwork material is configured to form a coherent bond with
adjacent portions of previously deposited formwork material shortly
after being deposited.
[0042] Preferably, the formwork material is meltable, such as a wax
compound, able to be melted at a relatively low temperature,
collected and recirculated to the reservoir, with minimal
processing required before being reused by the apparatus 1. The
formwork material is preferably configured to melt at a temperature
of less than 70.degree. C. to ensure that when heating the formwork
2 and a cast, concrete construction element engaged with the
formwork 2, that the heat does not significantly affect the
structure of the concrete construction element whilst curing, which
could reduce the strength of the construction element.
[0043] Alternatively, the formwork material is soluble, such as
plaster, able to be dissolved and optionally, collected and
recirculated to the reservoir. Similarly, the formwork material may
be dissolvable, such as foam, with a chemical solution. The
formwork 2 is dissolved after curing the construction element by
spraying the formwork 2 with a liquid, such as a chemical solution,
or by at least partially submerging the formwork 2 and the
construction element in a liquid, thereby dissolving the formwork
material and removing the formwork from the cast construction
element.
[0044] Referring to FIG. 1A, the formwork 2 is shown partially
fabricated, having an internal scaffold structure 11 configured as
a lattice, enclosed by a casting surface 12. The casting surface 12
forms a continuous shell around the scaffold structure 11, which
building material is ultimately poured over and set, thereby
forming the geometry of a construction element. The formwork 2 is
fabricated by the apparatus 1 as a hollow structure having an
internal scaffold 11 to minimise time and formwork material
required to fabricate the formwork 2, and also minimise time and
energy required to melt the formwork 2 when removing the formwork 2
from a cast construction element. The scaffold structure 11 may be
formed from a consistent, tessellated pattern (as shown in FIG. 1A)
or a non-regular structure of interconnected braces. The geometry
of the scaffold structure 11 is optimised according to the
functional requirements of the formwork 2 and associated
construction element cast in contact with the formwork 2. For
example, the density of the scaffold structure 11 may be varied
throughout the internal volume of the formwork 2 according to the
weight/density of a construction element it supports during
casting. Alternatively, the scaffold structure 11 may form one or
more conduits to allow the passage of a fluid through the formwork
2, to cool the formwork 2 during the fabrication process.
[0045] In FIG. 1A, the formwork 2 has sealed side-walls extending
between the substrate 10 and the casting surface 12. Alternatively,
at least portions of some of the side-walls are absent to allow
liquid or gas to pass through the scaffold structure 11 to rapidly
cool and harden the formwork 2, or heat the formwork 2 to reduce
shrinkage. Similarly, some or all of the build volume is
selectively temperature controlled to affect the temperature of the
formwork 2 and/or a construction element. The material deposition
head 7 may also comprise an additional jet (not shown) for
selectively expelling heated or cooled liquid/gas to affect the
temperature of the formwork 2 and, when heating, selectively melt
the formwork 2 to refine the surfaces of the formwork 2.
[0046] In FIG. 1B, the apparatus 1 is connected to a milling
spindle 13 attached to the arm 5. The apparatus 1 interchanges the
material deposition head 7 with the milling spindle 13, responsive
to computer instructions, and selectively mills the formwork 2 and
remove formwork material in specific locations. The milling spindle
13 may include one or more air inlets (not shown) in connection
with an air extraction (vacuum) system, to draw air proximal to the
milling spindle 13 into the inlets and collect particles of
formwork material, as the material is removed by the milling
spindle 13.
[0047] FIG. 1C shows an alternative aspect of the apparatus 1
having a robotic arm 14 rotatably secured to a carriage (not
shown). The carriage is moveable along a track (not shown) fixed to
a surface of the build volume. The robotic arm 14 has a plurality
of arm sections 15, 16 and 17 extending from the carriage, the
first arm section 17 being rotatably secured to the carriage and
each other arm section 15, 16 being rotatably connected to each
other around at least one axis. The distal arm section 16 from the
carriage is rotatably connectable to the material deposition head 7
(not shown), or the milling spindle 13. The robotic arm 14 is
rotatable around at least five axes of rotation allowing the
milling spindle 13 (or the deposition head 7) to be moved freely
within the build volume and deposit or mill formwork material
precisely.
[0048] In FIG. 1D, the robotic arm 14 illustrated in FIG. 1C is
connected to the material deposition head 7 and selectively
depositing portions of formwork material to fabricate an
alternative formwork 120. The apparatus 1 is configured to
automatically interchange between the material deposition head 7
and milling head 13 responsive to computer instructions. Other
heads may also be interchanged by the apparatus 1, such as a
robotic gripper (not shown), to grip and move items, or a spray gun
(not shown), to selectively spray fluid. For particularly
large-scale applications, multiple robotic arms 14 are provided
which move along one or more tracks, allowing simultaneous
deposition and/or milling of formwork material in different areas
of the build volume.
[0049] Referring to FIGS. 1C and 1D, the distal arm section 16 of
the robotic arm 14 may additionally be equipped with a spray nozzle
(not illustrated) for selectively applying a liquid, such as a
retarder, an acid, a pigment, paint, or masking material to the
formwork 2. As before, the movement of the robotic arm 14, and the
application of the liquid to the formwork 2, are computer
controlled. Typically the sprayed material is selectively applied
to form an image or functional configuration. Materials such as
acid and retarder may be applied in varying concentrations, thereby
varying the degree to which building material in contact with the
formwork 2 is acid etched and/or the depth to which the curing of
the building material is retarded. When a retarder is applied to
the formwork 2, after curing the construction element and removing
the formwork 2, uncured building material which has been in contact
with the retarder is removed from the construction element, for
example, by mechanical means such as pressurised water, thereby
revealing the image or functional feature applied to the formwork
and transferred to the construction element.
[0050] FIG. 2 shows the formwork 2 after fabrication by the
apparatus 1, having an undulating casting surface 12. A
construction element 17 is positioned next to the formwork 2 which
has been cast in contact with the formwork 2, resulting in a
surface having complementary geometry to the casting surface 2. The
construction element 17 was cast by: fabricating the formwork 2
within the build volume of the apparatus 1; affixing shutters (not
shown) to each side of the formwork 2, thereby creating a cavity
between the shutters and the casting surface 12 of the formwork 2;
pouring substantially liquid building material into the cavity;
curing the building material in contact with the shutters and the
formwork 2; and disassembling the shutters from the formwork 2 and
removing the formwork 2 from the cast construction element 17.
Alternatively, the formwork 2 is fabricated with extended
sidewalls, eliminating the need for shutters.
[0051] In FIG. 3, an alternative, construction element 18 is shown.
The construction element 18 has been cast according to the method
steps described above. The construction element 18 has a number of
`over-hanging` (otherwise known as `undercut`) surfaces 19, which
create recesses adjacent to the undercut surfaces 19 which prevent
a formwork (not shown) from being drawn linearly away from the
construction element 18 once the building material has cured,
consequently engaging the formwork with the construction element
18. Accordingly, the engaged formwork and construction element 18
were heated above the melting temperature of the formwork material,
thereby melting the formwork and removing it from the construction
element 18. The formwork material was collected and recirculated to
the formwork material reservoir, where the material may be reused
to fabricate another formwork by the apparatus 1.
[0052] In general, when removing formworks from construction
elements it is preferable to heat both within the build volume of
the apparatus 1 to melt the formwork, the build volume being
temperature controlled. The formwork material is then collected by
a drainage system, processed (if necessary) and recirculated to the
reservoir. Processing of formwork material may include filtration
to remove debris and chemical treatment to optimise the composition
of the material.
[0053] FIG. 4 is a partially sectioned view of a core 20,
fabricated by the apparatus 1 according to the method described
above, and further alternative cast construction element 21 engaged
with the core 20. A plurality of shutters 22 are fixed within the
build volume and spaced apart from the core 2, forming a cavity
around the core 20 into which building material is poured and set
to form the construction element 21. The core 20 has a plurality of
boreholes 23 into which the building material penetrates. After the
building material is cured, the core 20 and construction element 21
are heated above the melting temperature of the core 20 material,
melting the core 20 and draining the core material from the
construction element 21. Alternatively, if the core 20 is formed
from a dissolvable or soluble material, it is dissolved using a
liquid, such as a chemical solution. This allows the construction
element 21 to be cast having a complex, hollow internal structure,
in this case having a plurality of reinforcement braces 24
corresponding with the boreholes 23, efficiently and sustainably,
as the core 20 may be removed from the construction element 22
rapidly, without creating waste formwork material. This is
particularly advantageous with when casting specific design or
engineering features such as internal plenum structures,
ventilation shafts, conduits and chilled beams. Alternatively, at
least a portion of the core 20 may be left within the cast element
21 to provide functional requirement, such as a heat exchange (by
acting as a phase change material), insulation or structural
reinforcement.
[0054] FIG. 5 shows an alternative cast construction element 25,
formed using an alternative mould and core (not shown). In this
case, after the mould and core is melted and removed from the cast
element 24, an array of decorative and/or functional cavities 26
are revealed.
[0055] In FIG. 6, an optional, additional step of the casting
method is illustrated, in which a reinforcement structure 27 is
assembled within the build volume, prior to building material being
poured. This may involve fabricating support formworks 28 by the
apparatus 1, in specific locations, which the reinforcement
structure 27 is assembled on, supporting the reinforcement
structure 27 where necessary. The reinforcement structure 27 may be
assembled by the apparatus 1, or an alternative apparatus,
responsive to computer instructions. The support formworks 28 may
also be formed as part of another, complex geometry formwork (not
shown), such as a three-dimensionally curved structure, to support
a complementary, complex geometry reinforcement structure (not
shown). The reinforcement structure 27 may include functional
components such as conduits (for wiring, plumbing, heating or air
handling), insulation or acoustic treatment components.
[0056] In FIG. 7A a further alternative construction element 29 is
shown, formed as a column. As described above, two alternative
formworks 30, 31 are fabricated by the apparatus 1. The formworks
30, 31 are joined together forming a cavity therebetween. A
reinforcement structure 100 is placed within the cavity, being a
plurality of rods. Building material is poured into the cavity and
cured in contact with the formworks 30, 31 and reinforcement
structure 100, thereby forming the construction element 29 having a
corresponding geometry to the cavity and having an integral
reinforcement structure 100.
[0057] FIG. 7B shows a further alternative construction element
101, configured as a `chilled beam`, cast using a formwork (not
shown) fabricated by the apparatus 1 as described above. The
construction element 101 has a plurality of integral reinforcement
bars 102, to increase the strength of the element 101, and a
plurality of conduits 103, to allow a fluid, such as air and/or
water, to pass through the construction element 101 and regulate
the temperature of the construction element. In particular, the
conduits 103 are preferably configured to have cooled/heated water
flowing through inner conduits 104 and air passing through outer
conduits 105, thereby regulating the temperature of the environment
surrounding the construction element 101.
[0058] FIG. 8A shows the robotic arm 14 connected to the material
deposition head 7 fabricating an alternative formwork 32 on the
substrate 10. The formwork 32 is an extruded two-dimensional
illustration, formed from curved ribs extending from the substrate
10. When the shutters 33 are affixed to each side of the substrate
10 forming a volume between each shutter 33, the substrate 10 and
the formwork 32, building material is poured into the volume and
cured, forming a construction element 34. A previously cast
construction element 34, configured as a decorative panel with the
extruded illustration embossed into a surface, is positioned
adjacent to the substrate 10.
[0059] FIG. 8B shows an alternative arrangement of the scenario
described with respect to FIG. 8A, showing the robotic arm 14
connected to the material deposition head 7 fabricating an
alternative formwork 110. An alternative construction element 111
cast using the formwork 110 is positioned next to the formwork 110.
The cast construction element 111 has a corresponding geometry to
the formwork 110, thereby forming a `cofferred` floor slab having a
substantially hollow structure reinforced by a plurality of ribs
112.
[0060] FIG. 9 shows a further alternative, large-scale construction
element 35, cast using the method described above. The construction
element 35 is installed as part of a complex column node assembly,
joining a plurality of columns 36. The construction element 35 is
cast as a single part using one or more formworks fabricated by the
apparatus 1, to form a homogenous, strong structure to support the
substantial loads exerted by the columns 36.
[0061] In FIG. 10, a plurality of alternative formworks 37, 38, 39
are shown on a conveyor 40, each fabricated by the apparatus 1 as
described above. The robotic arm 14 is positioned above the
conveyor 40, rotatably connected to a composite lay-up head 41.
Responsive to computer instructions relating to the geometry of the
formwork 38 proximal to the robotic arm 14 on the conveyor 40, the
robotic arm 14 moves the composite lay-up head 41, selectively
applying composite material 42 to the formwork 38 in specific
locations. The composite lay-up head 41 is supplied by one or more
spindles of composite matting or tape, and wraps the formwork 38
with a continuous stream of composite material 42 or applies
sections of composite material 42. Alternatively, the composite
lay-up head 41 includes a nozzle (not shown) in fluid communication
with one or more composite material reservoirs (not shown) and,
responsive to computer instructions, selectively sprays one or more
layers of one or more composite materials in specific locations on
the formwork 38. Also, composite material may be applied to a
formwork manually, for example, where the geometry of the formwork
is particularly complex and inaccessible by the robotic arm 14.
[0062] Following (or during) the application of composite material
by the composite lay-up head 41 to the formwork 38 the composite
material 42 is at least partially cured in contact with the
formwork 38 to form one or more composite material elements. The
formwork 38 and respective composite material elements may then be
used in a number of ways during casting of a construction
element.
[0063] For example, the formwork 39 has composite material applied
to and cured in contact with a casting surface 43 to form a
homogenous composite material skin 44 corresponding with the
casting surface 43. The formwork 39 and composite skin 44 are then
at least partially covered by a building material and the building
material cured, thereby forming a construction element (not shown).
The building material cures in contact with the composite skin 44,
forming a bond between the building material and the composite skin
44. The formwork 39 is then removed from the construction element,
exposing the composite skin 44 secured to a corresponding portion
of the construction element. This is particularly applicable where
it is useful to coat one or more portions of a potentially complex,
internal structure of a construction element with composite
material, to benefit from the functional or aesthetic properties of
the composite material.
[0064] Alternatively, for example, after curing composite material
in contact with the formwork 38 to form a composite material shell
45, the formwork 38 is removed from the composite material shell
45. The composite material shell 45 is then at least partially
filled with a building material, and the building material cured,
thereby forming an alternative construction element (not shown),
having an integral composite material shell. This is particularly
applicable where it is useful to coat an external region of a
construction element with composite material, or form a continuous
composite shell around a construction element.
[0065] In FIG. 11, two alternative formworks 46, 47, are shown,
both formworks 46, 47 fabricated by the apparatus 1 as described
above, the second formwork 47 shown in partial section. The first
formwork 46 has portions of composite material 48 applied across a
top surface and sidewalls. The second formwork 47 is spaced apart
from the first formwork 46 providing a cavity 49 between the first
formwork 46 and second formwork 47. Building material is poured
into the cavity 49 and cured in contact with both formworks 46, 47
and the portions of composite material 48, forming a construction
element (not shown). Both formworks 46, 47 are then removed from
the construction element, revealing the construction element having
a corresponding geometry to the cavity 49 and having the composite
elements 48 integrally joined to the construction element across a
central void, providing a reinforcement structure.
[0066] In FIG. 12, a further alternative construction element 50 is
shown having an alternative composite material structure 51 secured
within the construction element 50. The composite material
structure 51 was formed by applying composite material to a
corresponding first formwork (not shown) fabricated by the
apparatus 1, and at least partially curing the composite material.
A second formwork (not shown) was then fabricated by the apparatus
1 in contact with the composite material structure 51, to create a
cavity. Building material was poured into the cavity and cured. The
first and second formworks were then removed, exposing a
column-like construction element 50 having a composite material
base 51 extending within the construction element 50, providing a
complex, composite skinned internal structure.
[0067] Optionally, the composite material structure 51 may also be
filled with a second building material and the second building
material cured, to form a second construction element enclosed
within the composite material structure 51. The second building
material may be specified to be the same as or different to the
building material used to cast the column-like construction element
50, therefore providing different functional or aesthetic
properties. For example, the column-like construction element 50
may be formed from concrete, providing compressive and tensile
strength, whereas the second construction element is formed from a
foamed polymer, to provide insulation.
[0068] FIG. 13A shows a further alternative formwork 52, fabricated
by the apparatus 1 as described above, with composite material webs
53 secured across a top surface. FIG. 13B shows two alternative
construction elements 54, 55 comprising composite material layers
sandwiched between solidified building material layers. The
construction elements 54, 55 were cast using the formwork 52, or a
similar formwork.
[0069] For example, formwork 52 defines a cavity 56 between an
outer formwork portion 57 and inner formwork portions 58. Building
material is poured into the cavity 56 and cured in contact with the
formwork portions 57, 58 and composite material webs 53, thereby
forming a solid construction element portion 59 having integral
composite material webs 53. The process may then be repeated,
fabricating additional outer and inner formwork portions (not
shown) on a top surface of the outer formwork portion 57 and inner
formwork portions 58, securing additional composite material webs
53 and casting an additional construction element portion 59. The
repetition of the process thereby produces construction element 55
in a staged process. Alternatively, only the formworks (and
composite webs) are fabricated as described above, in a staged
process, and the construction element 55 is then cast in a single
casting process, thereby forming a homogenous cast construction
element 55 having integral composite web 53 layers.
[0070] FIG. 14A illustrates a cross-section of an alternative
formwork 60 fabricated by the apparatus 1 as described above. The
formwork 60 comprises an inner portion 61 which has a plurality of
linear voids 62. During fabrication by the apparatus 1, composite
material 63 is applied to at least some of the surfaces of the
linear voids 62, forming composite webs running along the linear
voids 62. The formwork also comprises an outer portion 64 having
internal surfaces spaced apart from the inner portion 61, forming a
cavity 65. During the casting process, building material is poured
into the cavity 65, filling the cavity 65 and linear voids 62. The
building material is cured, thereby forming a solid construction
element 66, as shown in FIG. 14B. The construction element 66 is a
substantially hollow structure, having a network of beams 67
spanning its internal volume, each beam 67 having composite
material 63 extending along some of its surfaces, providing a
composite reinforcement structure. This is particularly useful when
producing construction elements which are likely to experience
specific and substantial dead or live loading cycles, for example,
seismic shocks, as the composite material coated beams 67 increase
the strength and stiffness of the construction element 66, without
significantly increasing its weight.
[0071] In FIGS. 15A-15E, a further alternative formwork 68 is
fabricated by the apparatus 1 in stages, by the robotic arm 14
selectively operating the material deposition head 7 and milling
spindle 13, responsive to computer instructions. In between each
stage of fabrication, the robotic arm 14 operates the composite
lay-up head 41 to selectively apply composite material portions 69
to the formwork 68. The repetition of fabricating the formwork 68
and applying composite material 69 to the formwork 68 produces
composite material layers 69 embedded within the formwork 68. A
second formwork 70 is fabricated or positioned adjacent to the
first formwork 68 forming a cavity 71 between the formworks 68, 70.
Building material is poured into the cavity 71 and cured, thereby
forming a solid construction element 72. The formworks 68, 70 are
then removed from the construction element 72 preferably by melting
at least the first formwork 68, revealing a hollow interior within
the construction element 72 having an integral composite scaffold
73, formed from the composite material portions 69.
[0072] It will be apparent that obvious variations or modifications
may be made which are in accordance with the spirit of the present
invention and which are considered within the scope of the
invention.
* * * * *