U.S. patent application number 17/449726 was filed with the patent office on 2022-01-20 for apparatus and method for making an object.
The applicant listed for this patent is ZYDEX PTY. LTD.. Invention is credited to Justin Elsey.
Application Number | 20220016811 17/449726 |
Document ID | / |
Family ID | 1000005883263 |
Filed Date | 2022-01-20 |
United States Patent
Application |
20220016811 |
Kind Code |
A1 |
Elsey; Justin |
January 20, 2022 |
APPARATUS AND METHOD FOR MAKING AN OBJECT
Abstract
An apparatus for making an object is disclosed. The apparatus
has a flexible element having an upwardly facing surface for
disposing thereon a material used to make the object, and a member
connected to an actuator that can move the member. A controller is
in communication the actuator. A method which may be executed using
the apparatus is also disclosed.
Inventors: |
Elsey; Justin; (St. Peters,
AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZYDEX PTY. LTD. |
Alexandria |
|
AU |
|
|
Family ID: |
1000005883263 |
Appl. No.: |
17/449726 |
Filed: |
October 1, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15186609 |
Jun 20, 2016 |
11141969 |
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17449726 |
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14486173 |
Sep 15, 2014 |
9375881 |
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15186609 |
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13818079 |
Jul 2, 2013 |
8877115 |
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PCT/AU2011/001067 |
Aug 20, 2011 |
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14486173 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 64/124 20170801;
B33Y 50/02 20141201; B29C 64/153 20170801; B29C 35/0805 20130101;
B29C 64/205 20170801; B33Y 30/00 20141201; B29C 35/0888 20130101;
B29C 2035/0827 20130101; B33Y 10/00 20141201; B29K 2105/0058
20130101; B29C 64/135 20170801; B29C 64/245 20170801 |
International
Class: |
B29C 35/08 20060101
B29C035/08; B29C 64/153 20060101 B29C064/153; B29C 64/124 20060101
B29C064/124; B29C 64/135 20060101 B29C064/135; B29C 64/205 20060101
B29C064/205; B29C 64/245 20060101 B29C064/245; B33Y 10/00 20060101
B33Y010/00; B33Y 30/00 20060101 B33Y030/00; B33Y 50/02 20060101
B33Y050/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 2010 |
AU |
2010903733 |
Claims
1. An apparatus for making an object, the apparatus comprising: a
composite flexible sheet that is transparent to a radiation, the
composite flexible sheet having an upwardly facing surface for
disposing thereon a material used to make the object, the material
being solidifiable by the radiation; a radiation source configured
to illuminate the material through the composite flexible sheet
with the radiation to solidify at least some of the material
adjacent the object being made.
2. An apparatus defined by claim 1 wherein the composite flexible
sheet is multilaminate.
3. An apparatus defined by claim 2 wherein the composite flexible
sheet comprises a silicone layer.
4. An apparatus defined by claim 3 wherein the composite flexible
sheet comprises a polyester layer.
5. An apparatus defined by claim 1 wherein the composite flexible
sheet comprises a layer of silicone bonded to a polyester film.
6. An apparatus defined by claim 1 wherein the composite flexible
sheet has a Young's modulus between 100 and 1000 MPa.
7. An apparatus defined by claim 1 wherein the composite flexible
sheet has a Young's modulus between 400 and 700 MPa.
8. An apparatus defined by claim 1 wherein the composite flexible
sheet has a Young's modulus of around 560 MPa.
9. An apparatus defined by claim 1 wherein the composite flexible
element forms at least part of a vessel configured to contain the
material.
10. An apparatus defined by claim 1 wherein the vessel is
removable.
11. An apparatus defined by claim 1 wherein the composite flexible
sheet has anti-stick properties.
12. An apparatus defined by claim 1 comprising a composite flexible
sheet tensioner.
13. An apparatus defined by claim 1 comprising a chassis and feet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority to
U.S. patent application Ser. No. 15/186,609, entitled "Apparatus
and method for making an object," filed Jun. 20, 2016, which
application is a continuation of and claims priority to U.S. patent
application Ser. No. 14/486,173, filed Sep. 15, 2014, now U.S. Pat.
No. 9,375,881, which is a continuation of and claims priority to
U.S. patent application Ser. No. 13/818,079, filed Jul. 2, 2013,
now U.S. Pat. No. 8,877,115, which claims priority to and is a U.S.
national stage entry of International Application No.
PCT/AU2011/001067, filed Aug. 20, 2011, which claims priority to
Australian Application No. 2010903733, filed Aug. 20, 2010, each of
which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention generally relates to an apparatus for
making an object and a method for making an object.
BACKGROUND OF THE INVENTION
[0003] A three dimensional object can be built up one section at a
time. A layer of material is solidified in the shape of a section
of the object. Once the section is formed, another is formed in
contact with the previous section. Repetition of this process
allows multi-laminate objects to be fabricated. This is the basis
of techniques such as rapid prototyping.
SUMMARY OF THE INVENTION
[0004] According to a first aspect of the invention, there is
provided a method for making an object, the method comprising the
steps of:
[0005] on an upwardly facing surface of a flexible element,
disposing a material used to make the object; and
[0006] causing relative movement between a member and both the
object being made and a downwardly facing surface of the element
while the member is in contact with the downwardly facing surface,
the relative movement causing the upwardly facing surface to adopt
a form.
[0007] In the context of this specification, an object is a
tangible object. It may, for example, be rigid or resilient. It may
have one or more hollows or voids, such as that of a cup or tennis
ball, for example.
[0008] Generally but not necessarily, the material is a liquid. The
liquid may comprise a layer of liquid. In alternative embodiments,
the material may comprise a powder such as a fluidized polymer
powder, or a fluid or paste. Any suitable material may be used.
[0009] A relatively modest volume of material, for example a
liquid, may be required. Generally, but not necessarily for all
embodiments, a layer of the liquid is disposed over the surface. If
the liquid material was alternatively disposed under the flexible
element in a vat, for example, a relatively large volume of
liquid--for example, of the order of 10 L--may be required. This
may be far in excess of the volume of the object, in which case the
liquid may only be slowly consumed over an extended period in which
several objects are made, and during which the liquid may become
contaminated or otherwise degraded. A typical cost for liquid used
in the production of the object may be of the order of several
hundred dollars per litre, and thus costly waste may be reduced by
disposing the material over the surface. A further advantage of
using an upwardly facing surface is that a surface level of the
liquid does not need to be controlled, whereas an apparatus having
a liquid disposed in a vat under the flexible element requires the
surface level to be maintained while the object is being made. This
may, for example, require relatively complex material overflow
management, especially if a part of the apparatus (such as a drive
shaft) moves into the material.
[0010] In an embodiment, the method comprises the step of
decreasing the separation of the object being made and the upwardly
facing surface. The object may be moved towards the upwardly facing
surface. For example, the object being made may be brought to
within one section thickness of the nominal position of the
upwardly facing surface in preparation for solidification of some
of the material to form the next section of the object. Reducing
the separation of the object being made and the surface may squeeze
the material which in turn presses on the surface to cause it to be
pushed. This may cause the upwardly facing surface to deviate from
the form.
[0011] In the context of this specification, a section is to be
understood to encompass a slice of the object. A planar section
encompasses a portion of the object located between two parallel
planes that intersect the object. Generally, but not necessarily,
the sections formed are planar sections.
[0012] In an embodiment, the relative movement flattens the
upwardly facing surface. The member may be moved horizontally. The
member may be relatively moved across the downward facing
surface.
[0013] Generally, but not necessarily, the desired form of the
upwardly facing surface is flat. A flat surface may be required to
form planar sections. If this deviation from a planar form is not
corrected the sections may not have the desired geometry. The
member may be relatively moved to have the surface adopt the
desired form.
[0014] In an embodiment, the method comprises the step of
illuminating the material with a radiation to solidify at least
some of the material adjacent the object being made. The step of
illuminating and solidifying may complete an entire section of the
object being made. The object may be fabricated by sequentially
illuminating each of a plurality of material layers to form
respective sections. Each section may be an entire section of the
object. Each section may be formed adhered to the upwardly facing
surface. The surface may be subsequently separated from the
attached section before the next section is made. Each entire
section may comprise an entire planar section.
[0015] During the step of illuminating the material, the member may
contact a portion of the element directly beneath the object being
made to prevent the portion sagging. The flexible element may sag
by the force of gravity. This is undesirable because the sections
formed adjacent the upwardly facing surface will deviate from the
desired form causing fabrication of a malformed object.
[0016] The step of illuminating may comprise illuminating the
material with a radiation that has passed through a window of the
member. There may be no relative movement between the member and
the element during the formation of an entire section of the
object.
[0017] Alternatively, during the formation of an entire section,
the material adjacent a portion of the flexible element supported
by the member may be solidified, and then the member may be
relatively moved to support another portion in preparation to
solidify the material adjacent the other portion.
[0018] Illumination may also attach the solidified material to the
object being made.
[0019] In an embodiment, during the relative movement the member
passes directly beneath the object being made. This may expel some
of the material which is located between the element and the object
being made. This may also flatten a portion of the element directly
beneath the object.
[0020] In an embodiment, the method comprises, after the step of
illumination and solidifying the material to form an entire section
of the object being made, the step of further moving the member
relative to the downwardly facing surface while the member is in
contact with the downwardly facing surface to a position where the
member is not directly beneath the object being made.
[0021] The further movement may be a sliding movement of the member
along the downwardly facing surface. Sliding movement requires less
force than pulling the element and the member apart because in the
later case the force exerted by atmospheric pressure must be
overcome. Sliding the member away from beneath the solid section
exposes the downwardly facing surface of the flexible element to
the atmosphere. Exposing the downward surface to atmosphere thus
allows the flexible element to distort freely and facilitates
peeling of the section from the element. If the member was to
remain beneath the flexible element a relatively extreme separation
force may be required to separate the section from the flexible
element. The extreme force may be transferred to the object being
made during separation and damage it. In other embodiments, the
movement is a rolling movement which may have similar advantages to
using a sliding movement.
[0022] Also, the force applied by the sliding member is
predominantly tangential to the downwardly facing surface of the
flexible member causing the flexible member to tension and take at
least some of, if not most of, the force, reducing the force being
applied to the object being made. To facilitate this, the sheet may
be flexible but may have a sufficiently high Young's modulus to
resist stretching.
[0023] Especially delicate objects may thus be made that may not be
made using another approach.
[0024] In an embodiment, the method comprises the step of
separating the object being made and the upwardly facing surface.
The step of the separating may comprise the step of moving the
object being made away from the flexible element and the
member.
[0025] This may cause the flexible element to distort to peel away
from the section. The forces experienced by the section during
peeling separation from the surface is typically much less than the
force generated when separating the section from the surface in
other ways. Consequently, the use of a flexible element may reduce
the risk of damage to the section and/or the object being made.
[0026] The object being made and the surface may be separated only
after the formation of an entire section of the object being made.
This may aid in the fabrication of spans of overhanging features of
the object with fewer, or without any, supporting scaffolds.
Example overhanging features include the arms of a "T" shaped
object. The fabrication of overhangs may be problematic for some
methods that do not form an entire section before separation.
Moving the object being made from the flexible element and the
member may reduce or eliminate the need to handle the sheet or to
have things contacting it which can cause the element to crease,
wear or damage. It may also reduce or eliminate the need to have
mechanisms in contact with the upwardly facing surface of the
element which may interfere with the distribution of the liquid on
the sheet.
[0027] In an embodiment, the method comprises the step of disposing
a friction-reducing substance between the element and the
member.
[0028] According to a second aspect of the invention, there is
provided a method for making an object, the method comprising the
steps of:
[0029] on an upwardly facing surface of a flexible element,
disposing a material used to make the object;
[0030] illuminating the material with a radiation to solidify at
least some of the material adjacent the object being made to form
an entire section of the object; and then
[0031] causing relative movement between a member and a downwardly
facing surface of the element while the member is in contact with
the downwardly facing surface to a position where the member is not
directly beneath the object being made.
[0032] In an embodiment, during illumination the member is directly
beneath the object being made.
[0033] In an embodiment, the method comprises the step of
separating the object being made and the upwardly facing surface.
The step of separating may be done while the member is not directly
beneath the object being made. The step of separating may comprise
the step of moving the object being made from the flexible element
and the member.
[0034] Were possible, steps of the first aspect of the invention
may be combined with any one or more steps of the second aspect of
the invention.
[0035] According to a third aspect of the invention, there is
provided an apparatus for making an object, the apparatus
comprising:
[0036] a flexible element having an upwardly facing surface for
disposing thereon a material used to make the object;
[0037] a member in contact with a downward facing surface of the
element;
[0038] an actuator arranged to cause relative movement between the
member and both the downwardly facing surface and the object being
made while the member is in contact with the downwardly facing
surface, the relative movement causing the upwardly facing surface
to adopt a form.
[0039] In an embodiment, the apparatus comprises a controller in
communication the actuator, the controller is configured to execute
the step of the actuator causing the relative movement.
[0040] The apparatus may, but not necessarily, be generally
configured such that the upwardly and downwardly facing surfaces
are horizontally orientated. The apparatus may, for example, have a
chassis with attached feet configured to support the chassis above
a surface such as a bench, and the flexible member is mounted
relative to the chassis so that when the chassis is so supported
the surfaces have a horizontal orientation.
[0041] The material may be a liquid. The liquid may be a layer of
liquid. In alternative embodiments, the upwardly facing surface is
for disposing thereon a powder or other material used to make the
object.
[0042] In an embodiment, the apparatus comprises a positioner
configured to alter the separation of the object being made and the
surface. The controller may be in communication with the positioner
and is configured to execute the step of decreasing the separation
of the object being made and the surface. This may place the object
being made in a suitable position for the formation of the next
section to be made. The surface may deviate from the form when the
separation of the object being made and the surface is
decreased.
[0043] The section of the object and the surface may be later
separated by the positioner.
[0044] An embodiment comprises a radiation source configured to
illuminate the material with a radiation to solidify at least some
of the material adjacent the object being made. The radiation
source may be a light source. The radiation may be a light.
[0045] In an embodiment, the controller is in communication with
the radiation source. The controller may be configured to execute
the step of illumination of the material while the member contacts
a portion of the downwardly facing surface directly beneath the
object being made. This may prevent the portion sagging, providing,
in some embodiments, a more planar section as generally, but not
necessarily, desired.
[0046] In an embodiment, the member comprises a window configured
to pass the radiation. The window may comprise an aperture. The
window may comprise material transparent to the radiation. The
window may comprise at least two rollers spaced apart so that the
radiation can be transmitted between them.
[0047] In an embodiment, the controller is configured to execute
the step of illuminating the material through the window. The
controller may not execute the step of causing the relative
movement of the member during the irradiation in which an entire
section of the object is solidified. Alternatively, during the
formation of an entire section of the object, the material adjacent
a portion of the flexible element supported by the member may be
solidified, and then the member may be relatively moved by the
controller to support another portion in preparation to solidify
the material adjacent the other portion.
[0048] In an embodiment, the flexible element is transparent to the
radiation. The radiation source may be located below the element.
The radiation may pass through the element.
[0049] An embodiment of the apparatus comprises a radiation
manipulator configured to manipulate the radiation. The radiation
manipulator may impart a spatial feature to the radiation. The
radiation manipulator may impart a temporal feature to the
radiation. The shape of each section may thus be individually
controlled by the action of the radiation manipulator on the
light.
[0050] In an embodiment, the radiation manipulator is configured to
scan the radiation relative to the surface.
[0051] In an embodiment, the controller is configured to execute
the step of relatively moving the member such that the member
passes directly beneath the object being made.
[0052] In an embodiment, the relative movement flattens the
surface.
[0053] In an embodiment, the controller is configured to execute,
after the step of illuminating and solidifying the material to form
an entire section of the object being made, the step of further
moving the member relative to the downwardly facing surface while
the member is in contact with the downwardly facing surface, the
further relative movement positioning the member relative to the
downward facing surface to a position where the member is not
directly beneath the object being made. The controller may be
configured to execute the step of increasing the separation of the
object being made and the upwardly facing surface. The object may
be moved away from the upwardly facing surface.
[0054] In an embodiment, the member comprises an elongate edge that
contacts the downwardly facing surface.
[0055] In an embodiment, the member comprises at least one roller
that contacts the flexible element.
[0056] In an embodiment, the member comprises a planar surface that
contacts the downwardly facing surface.
[0057] In an embodiment, the flexible element forms at least part
of a vessel configured to contain the material. The vessel may be a
trough. The vessel may be a dish. The vessel may prevent the
material from falling off or flowing off the element. This may
reduce costly material consumption.
[0058] In an embodiment, the flexible element comprises a flexible
sheet. The flexible sheet may have a unitary construction. For
example, the flexible sheet may not be backed by another element.
The flexible sheet may be, for example, a membrane. Alternatively,
the sheet may be a composite.
[0059] In an embodiment, the flexible element may have a Young's
modulus of between 100 and 1000 MPa. The Young's modulus may be
between 400 and 700 MPa. The Young's modulus may be around 560
MPa.
[0060] An embodiment of the invention comprises a flexible element
tensioner. The tensioner may comprise an element-contacting
component for contacting the downwardly facing surface. The
tensioner may comprise one or more biasing elements that bias the
element-contacting component towards the downwardly facing surface.
The element-contacting component may comprise a ring. The one or
more biasing elements may comprise a spring arrangement. The
arrangement may comprise an extension spring operationally coupled
to the element and the component. Alternatively or additionally,
the downwardly facing surface may be biased into the frame by
gravity.
[0061] In an embodiment, a friction-reducing substance is disposed
between the member and the element.
[0062] In an embodiment, the controller is configured to receive
instructions for making the object. The controller may receive the
instructions in the form of data indicative of a plurality of
sections to be formed sequentially by the device. The sections may
be individually determined. Each individually determined section
may differ from another of the sections by, for example, the shape
of their respective boundaries. Not every section needs to be
different, however. The controller may be configured to coordinate
movement of the member and the positioner, and the light source,
and in some embodiments other parts, such that the plurality of
sections are formed sequentially in accordance with the received
instructions. The controller may comprise a processor.
[0063] According to a fourth aspect of the invention, there is
provided an apparatus for making an object, the apparatus
comprising:
[0064] a flexible element having an upwardly facing surface for
disposing thereon a material used to make the object;
[0065] a member in contact with a downwardly facing surface of the
element, the member being for shaping the element;
[0066] an actuator arranged to cause relative movement between the
member and the element;
[0067] a radiation source configured to illuminate the material
with a radiation to solidify at least some of the material adjacent
the object being made; and
[0068] a controller in communication the actuator and the radiation
source, the controller is configured to execute the steps of:
[0069] illuminating the material when so disposed with the
radiation to solidify at least some of the material adjacent the
object being made to form an entire section of the object; and
then
[0070] causing the relative movement between the member and the
downwardly facing surface while the member is in contact with the
downwardly facing surface to a position where the member is not
directly beneath the object being made.
[0071] In an embodiment, during illumination the member is directly
beneath the object being made.
[0072] In an embodiment, the apparatus may comprise a positioner
configured to alter the separation of the object being made and the
surface. The controller may be in communication with the positioner
and further configured to execute the step of separating the object
being made and the upwardly facing surface. The step of separating
may be done while the member is not directly beneath the object
being made. The step of separating may comprise the step of moving
the object being made away from the flexible element and the
member.
[0073] Were possible, any one or more features of the third aspect
of the invention may be combined with any one or more features of
the fourth aspect of the invention.
[0074] According to a fifth aspect of the invention, there is
provided a method for making an object, the method comprising the
steps of:
[0075] on a surface of a flexible element, disposing a material
used to make the object; and
[0076] causing relative movement between a member and the element,
the relative movement causing the surface to adopt a form.
[0077] Were possible, any one or more features of the fifth aspect
of the invention may be combined with any one or more features of
the first aspect of the invention.
[0078] According to a sixth aspect of the invention, there is
provided an apparatus for making an object, the apparatus
comprising:
[0079] a flexible element having a surface for disposing thereon a
material used to make the object; and
[0080] an actuator arranged to cause relative movement between a
member and the element, the relative movement causing the surface
to adopt a form.
[0081] Were possible, any one or more features of the sixth aspect
of the invention may be combined with any one or more features of
the third aspect of the invention.
[0082] Any liquid used to make a solid object referred to in this
specification may, as appropriate, be replaced with any suitable
material or fluid used to make a solid object, and vice versa.
BRIEF DESCRIPTION OF THE FIGURES
[0083] In order to achieve a better understanding of the nature of
the present invention, embodiments will now be described, by way of
example only, with reference to the accompanying figures in
which:
[0084] FIGS. 1 to 11 show schematic elevation views of one
embodiment of a device for making an object during the various
stages of its use;
[0085] FIGS. 12 to 17 show perspective views of examples of members
that may form part of a device for making an object;
[0086] FIGS. 18 to 24 show schematic elevation views of another
embodiment of a device for making an object;
[0087] FIGS. 25 to 27 show perspective views of further examples of
a member that may form part of a device for making an object;
[0088] FIG. 28 shows a flow diagram of an embodiment of a method
for making an object;
[0089] FIGS. 29 to 31 show schematic views of example radiation
sources that may form part of a device for making an object;
[0090] FIGS. 32 to 33 show schematic elevation views of another
embodiment of a device for making a solid object;
[0091] FIG. 34 shows a schematic view of a friction reducing
substance between an example flexible element and an example
member;
[0092] FIGS. 35 and 36 show schematic elevation views of another
embodiment of a device for making a solid object;
[0093] FIG. 37 shows an example architecture of a controller for
controlling the devices of the preceding figures; and
[0094] FIG. 38 shows an example of a tensioner that may be
incorporated into a device for making a solid object.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0095] FIGS. 1 to 11 show schematic views of one embodiment of an
apparatus at which an object can be made, the apparatus being
generally indicated by the numeral 100. The figures taken in
sequence indicate one embodiment of a method for making an object.
Coordinate axes are shown in the figures where x and y are
horizontally orientated and z is vertically orientated.
[0096] The apparatus 100 has a flexible element in the form of a
substantially transparent sheet 101 over which a layer of
photohardenable liquid 104 is disposed. A photohardenable liquid
(or photocurable liquid) is a liquid that hardens when exposed to a
radiation such as visible or invisible light (ultraviolet light,
for example). Example wavelengths of suitable light include 355 nm
and 405 nm. In some embodiments, radiation sources other than light
may be used. For example, the radiation source may be ionizing or
non-ionizing radiation.
[0097] The photohardenable liquid may comprise a mixture of
acrylate monomers and oligomers, photoinitiators, colourants and
stabilizers such that the mixture polymerizes when exposed to
suitable light. Example liquids include Somos NEXT from DSM Somos,
USA, and KZ-1860-CL from Allied PhotoPolymers, USA.
[0098] Sheet 101 may possess anti-stick properties in relation to
the photohardenable material 104 when it is cured in contact with
the sheet. Suitable materials for sheet 101 include FEP
fluoropolymer film manufactured by Du Pont, USA. The film may be of
around 125 micrometers thickness, but may be thicker or thinner as
appropriate. The sheets are flexible but may not be particularly
elastic, having a Young's modulus of 560 MPa. Generally but not
necessarily, a Young's modulus of between 100 and 1000 MPa may be
suitable. Another example of a suitable material is a PFA
fluoropolymer film, also manufactured by Du Pont. Generally any
suitable material may be used for the element.
[0099] In this embodiment, the sheet 101 is not backed by another
material or layer, and has a unitary construction. In other
embodiments the sheet may have a multilaminate construction. For
example, the sheet may comprise a layer of silicone bonded to a
polyester film, the film providing a high Young's modulus and the
silicone providing a superior nonstick surface in relation to the
photohardenable material 104. Other materials or laminates of
different materials may alternatively be used.
[0100] The sheet 101 and side walls 106 form a shallow vessel in
the form of a trough or dish 108 for containing the photohardenable
liquid 104. The vessel may have a volume sufficient to hold enough
liquid to build an entire object without being replenished.
Optionally, a conduit may connect the vessel and a supply of the
liquid to replenish the liquid as it is consumed. The sheet 101
forms the base of the trough. The trough 108 and contained liquid
104 can be easily removed from the apparatus and replaced with
another trough and liquid, thus providing a convenient means for
replacing damaged troughs or making objects from different
materials.
[0101] The apparatus has movable member 110 that can be moved
horizontally along the x-axis by a linear actuator 112 and drive
shaft 114. The actuator may comprise any one or more of linear
motors, drive belts, stepper motors, rack and pinion arrangements,
for example, or generally any suitable components arranged to
provide actuation. The member pushes against the underside 103 of
the sheet 101. In another embodiment, the member remains stationary
while the object being made and the sheet are moved. In yet another
embodiment, both the object being made and the sheet are moved in
opposition to the movement of the member. Generally any suitable
combination of movement may be used if there is relative movement
of the member to both the sheet and the object being made.
[0102] The embodiments of FIGS. 1 to 11 and 18 to 24 are each
configured such that in use the sheet 101 is horizontally
orientated. The apparatus may, for example, have a chassis 130 with
attached feet 132,133 configured to support the chassis above a
surface such as a bench, and the sheet is mounted relative to the
chassis so that when the chassis is so supported the sheet has a
horizontal orientation. In other embodiments, the surface of the
sheet which the liquid is disposed on may be inclined at up to 45
degrees to the horizontal (that is, the surface is upwardly
facing), provided that the vessel walls are sufficiently high to
contain the fluid. Mounting brackets 152,154,156,158 may be used to
ensure that apparatus components are maintained in their correct
position and orientation relative to the chassis.
[0103] A radiation source in the form of a light source 116 may be
activated so that it emits spatially and/or structured light 118
capable of selectively hardening areas of the photohardenable
liquid 104 to form a section of the object. Light source 116 may,
for example, incorporate a light manipulator such as an image
projection system depicted in FIG. 29 and generally indicated with
the numeral 116a, comprising light source 116 emitting light 162,
relay optics 163, turning prism 164, spatial light modulator 165
controllable by controller 168, and projection lens 166.
Alternatively, light source 116 may be a light beam scanning
apparatus depicted in FIG. 30 and generally indicated by the
numeral 116b, comprising a laser source 171 emitting light 172 of
wavelength of around 350 nm, for example, collimating and/or
focusing optics 173, scanning mirror 174 whose rotation is
controllable in one or more axes by mirror controller 178,
optionally a second controllable mirror not shown in the figure,
and optionally a projection lens 175 such as an F-Theta lens.
Controller 178 can be configured to scan the mirror 174
(coordinated with a second mirror, if present) in a raster scanning
mode, or alternatively in a vector scanning mode. FIG. 31 shows a
second type of beam scanning apparatus generally indicated by the
numeral 116c comprising a laser source 181 emitting light 182,
collimating and/or focusing optics 183, polygon mirror 184
rotatable around an axis 185 and controllable by controller 188,
and optionally a projection lens 186 such as an F-Theta lens. As
the apparatus of 116c may only scan light in the y-axis according
to the coordinate system shown in FIG. 31, the apparatus resides on
a translation stage 187 which can move the apparatus in the
x-direction, enabling the projected light to address locations in
the x and y dimensions. The translation stage may comprise any one
or more of linear motors, drive belts, stepper motors, rack and
pinion arrangements, for example, or generally any suitable
components arranged to provide translation. Apparatus 116c is
suitable for operating in a raster scanning mode. The light source
may, in some embodiments, comprise an incandescent light or light
emitting diode, for example. Any suitable light source may be
used.
[0104] Referring again to FIGS. 1 to 11 and 18 to 24, a positioner
120 capable of linear motion along the z-direction is coupled to
and moves a platform 121 on which the object being made is mounted.
The positioner 120 positions the object being made 122 relative to
the upwardly facing surface 102 of the sheet 101. The positioner
may comprise any one or more of linear motors, drive belts, stepper
motors, rack and pinion arrangements, for example, or generally any
suitable components arranged to provide linear motion.
[0105] A sequence of actions can be performed with the apparatus
100 to form a new section of the object 124 and non-destructively
separate it from the sheet 101. The process begins as shown in FIG.
1, with the previous sections of the object under fabrication 122
distanced from the sheet 101 and the member 110 retracted from the
underside of the sheet 101.
[0106] Next, as shown in FIG. 2, positioner 120 lowers the object
being made 122 towards the sheet 101 to a final position which is
one section-thickness above the surface 102 when flat.
[0107] The sheet 101, not being supported however, will undesirably
deflect away from the object being made 122 as shown in FIG. 2, due
to the trapped fluid between them causing the separation of the
solid object being made from the surface 102 to be typically many
sections thick. The surface also deviates from a flat form.
[0108] The thickness of one section is typically in the range of 10
microns to 250 microns, but it may be less if particularly fine
fabrication resolution is required, and greater if a relatively
coarse fabrication resolution is required.
[0109] Next, as shown in FIG. 3, actuator 112 is engaged to move
the flexible element shaping member 110 along the underside 103 of
the sheet 101. This action lifts and shapes the sheet 101 to have
it adopt a flat configuration or form while forcing excess
photohardenable liquid 104 out of the gap between the previously
hardened sections 122 and the sheet 101. At least some of the force
applied to the sheet by the moving member may be taken by the sheet
and not transferred to the object under construction. Having a
flexible sheet that is not particularly elastic, as discussed
above, may allow for especially delicate objects to be
fabricated.
[0110] Next, as shown in FIG. 4, light 118 having spatial features
in accordance with the sectional geometry of the object being made
is emitted from light source 116 to selectively harden regions of
the layer of photohardenable liquid 104 in contact with the
previously formed sections 122 to form a new hardened section 124.
In this embodiment, the arm connecting 110 and 112 is actually a
pair of spaced-apart arms and the light passes between the arms.
Alternatively, the arm may be a single arm disposed to one side of
the light so that the light may pass.
[0111] Next, as shown in FIG. 5, mechanical actuator 120 is engaged
to raise the previously formed sections 122 and newly formed
section 124, causing the sheet 101 to stretch and distort. Once the
peeling angle 126 is sufficiently large the sheet will peel away
from the newly formed section 124 and the apparatus 100 is ready
for the process to start again, as shown in FIG. 6. The subsequent
sequence, depicted in FIGS. 7 to 11, is identical to the first
sequence depicted in FIGS. 1 to 6 except that the movement
direction of the member 110 is reversed. Repeating this sequence of
actions enables a multilaminate object to be fabricated section by
section.
[0112] The member 110 in this embodiment of an apparatus lifts the
sheet 101 to its level position, so that the sheet 101 adopts a
flat configuration. This action may also force excess
photohardenable liquid 104 out of the gap between the sheet 101 and
the previously hardened sections 122. A flat section of consistent
thickness may subsequently be formed.
[0113] In other embodiments, the member may be configured and
manipulated such that the sheet is caused to adopt a configuration
other than a flat configuration. This changes the distribution of
the liquid material accordingly so that the spatial configuration
of the liquid material between the sheet and the object is changed
or modified to the desired shape. For example, a curved sheet
configuration may be advantageous if the object being made has a
rounded shape or if the light source 116 projects light 118 to a
curved focal plane. The member may be, in the embodiment, arranged
to move relative to the sheet in a non-linear manner. For example,
the member may move along an arc as it moves relative to the sheet
causing the sheet to have an arc configuration. The member may
generally move along any other non-linear path to cause the sheet
to take on a corresponding configuration.
[0114] Alternatively, the sheet may be shaped or configured so that
its upper surface has a desired configuration while maintaining a
flat lower surface configuration against which the member may move.
Thus, as the section of the object is formed, the lower surface of
the object section takes on the same configuration as the upper
surface of the sheet. It will be understood that the configuration
of the upper surface of the sheet may be any suitable desired
geometrical arrangement.
[0115] Several other examples of flexible element shaping members
are illustrated in FIGS. 12 to 17 and FIGS. 25 to 27. FIG. 12 shows
a blade-like member 200 comprising a wedge 210. FIG. 13 shows a
member 300 comprising a cylindrical roller 332 free to rotate on
bearings 334. For these embodiments of members, after the member
transits across the underside of the sheet, the membrane may be
maintained in its level position, or sufficiently close to it, by
the tension in the sheet.
[0116] The sheet may sag because of the weight of the material and
the sheet itself. The amount of sheet sag may, in some
circumstances, be too great to satisfy the required fabrication
tolerances. In these instances the member may support part or all
of the area of the membrane presented for radiation exposure. FIG.
14 shows one embodiment 400 of such a member. It comprises a window
434 fabricated of a material transparent to the curing radiation
118 emitted by light source 116. For example, when the curing
radiation is 405 nm wavelength light, the window 434 may comprise a
plate of fused silica. The edges of the window 434 may be beveled,
or even wedged, to reduce the risk of a scratch or other mark being
made on the underside surface 103 of the sheet. In operation, a
member of this embodiment may be relatively narrow. The light may
be emitted through the member as it traverses the underside of the
sheet, that is, during the transition from the state shown in FIG.
2 to the state shown in FIG. 3. Intermediate states during the
transition are shown in FIGS. 32 and 33, showing section 124 being
hardened in stages, indicated by 124a and 124b, by light exposure
through the member as it moves. Only a narrow exposure window is
presented at any instant, making the member of FIG. 14 more
suitable for use with raster-type light sources as opposed to
vector scanning type light sources. For example, the light source
may comprise a scanning laser system operating in raster mode with
the fast scan direction aligned with the y-axis (out of the page)
and the slow scan direction aligned with x-axis according to the
axes show in FIG. 1, and the scan speed in the x-dimension
coordinated with the motion of the member so that it is projecting
through the window. The apparatus 116b of FIG. 30 or apparatus 116c
of FIG. 31 may be adapted to operate in such a fashion. A similar
result may be achieved with a progressive display using a digital
multimedia projector. The apparatus 116a depicted in FIG. 29 may be
operated in this manner.
[0117] It is possible to use a completely opaque supporting member.
For example, the light may fall on a portion of the sheet 101
adjacent the leading 436 or trailing edge 438 of the member, as
depicted in FIGS. 35 and 36. The member of this embodiment may not,
however, necessarily be opaque.
[0118] FIG. 15 shows a second type of supporting member apparatus
500 comprising two rollers 536 and 538 free to rotate around their
axes on bearings 540 and 542. The rollers support the sheet 101 as
the member apparatus is moved underneath the sheet. There is a gap,
a window 543, between the two rollers through which the light can
pass. The gap can be made arbitrarily narrow so that the amount of
membrane sag in this gap is acceptable. The use of rollers reduces
the effect of friction between the member and the sheet 101. Again,
raster light sources such as a laser scanning apparatus operating
in raster mode or a digital multimedia projector are suitable for
use in conjunction with such a member.
[0119] FIG. 16 shows another embodiment of a member 600. It
comprises an elongated window 644 surrounded by a frame 646. The
frame 646 may be constructed, for example, from aluminum or
stainless steel, and thus offers a means of implementing an
embodiment of the present invention without using expensive
transparent materials.
[0120] Elements of the presented embodiments of a member may be
combined. For example, any member may be enhanced by adding a
roller at its leading edge and/or its trailing edge to minimise
friction between it and the sheet, as depicted by the apparatus 700
in FIG. 17 comprising rollers 736,738 and window 734.
[0121] Some embodiments of the member may fully support the area of
the sheet presented for exposure to the light. In this case a
slightly different operating procedure may be employed for forming
a layer of material, hardening it to form a section, and separating
the section from the provided surface.
[0122] FIGS. 18 to 24 show another embodiment of an apparatus at
which an object can be made generally indicated by the numeral 800,
where parts similar to those in the embodiment of FIG. 1 are
similarly numbered. The figures taken in sequence indicate one
method with which the apparatus forms and separates a section
according to an embodiment of a method for making an object.
[0123] The following sequence of actions may be performed with the
apparatus 800 to form a new solid section 124 and non-destructively
separate it from the sheet 101. The process begins with the
previous sections of the object being built 122 a distance from the
sheet 101 and the member 110 retracted from the underside of the
sheet 104, as shown in FIG. 18. Next, mechanical actuator 120
lowers the object being built 122 towards the sheet 101 to a final
position which is one section-thickness above the sheet surface 102
when in the flat configuration. The sheet 101, not being supported,
will deflect away from the object 122 as shown in FIG. 19 resulting
in a separation generally greater than one section thickness. Next,
mechanical actuator 112 is engaged to move the member 110 along the
underside the sheet as shown in FIG. 20. This corresponds to step
1004 of the method shown in FIG. 28 generally indicated by numeral
1000. This action lifts the sheet 101 to its level position while
forcing excess photohardenable liquid 104 out of the gap between
the previously hardened sections 122 and the sheet 101. Next,
structured light 118 in accordance with the cross-sectional
geometry of the object under construction is emitted from light
source 116 to selectively harden regions of the layer of
photohardenable liquid 104 in contact with the previously formed
sections 122 to form a new solid section 124, as shown in FIG. 21.
The light source 116 may project a rasterised image, or it may
operate in a vector scanning mode. The member 110 provides a
support for the sheet 101 to prevent sagging during the exposure,
that is, the exposure takes place through the member 110.
[0124] Next, mechanical actuator 112 is engaged to retract the
member 110 from the underside of the previously hardened section
124, as shown in FIG. 22.
[0125] Although the movement of the member is, in the presented
embodiments, parallel to the nominal plane of the sheet and thus
horizontal, it need not be strictly horizontal. Some degree of
non-horizontal movement may be accommodated by a corresponding
distortion of the flexible member. Consequently, the relative
movement may have a component parallel to the surface (that is,
perpendicular to the direction of the gravitational force), but
also some component perpendicular to the surface. The resultant
movement may be substantially parallel to the surface.
[0126] Next, positioner 120 is actuated to raise the previously
formed sections 122 and newly formed section 124 past the level
position of the membrane, as shown in FIG. 23. Once the peeling
angle 126 is sufficient the membrane will peel away from the newly
formed section 124 and the apparatus is ready for the process to
start again, as shown in FIG. 24. Repeating this sequence of
actions enables a multilaminate object to be fabricated section by
section.
[0127] In the embodiments of FIGS. 1 to 11 and 18 to 24, the fluid
contained in the trough flows over the surface under the influence
of gravity, causing the fluid to be disposed on the surface.
Alternatively, the fluid may be periodically applied over the
surface from a nozzle, or applied with a wiping action similar to
the action of a windscreen wiper blade.
[0128] One embodiment of a member which fully supports the
radiation-exposed area of the sheet is shown in FIG. 25 generally
indicated by the numeral 900. It comprises a plate 910 of material
transparent to the light from light source 116. It may, for
example, be fabricated from fused silica when light of wavelength
405 nm is used. Alternatively, the plate may be fabricated from
poly(methyl methacrylate) (PMMA), polycarbonate, soda-lime glass or
any other suitable material that is sufficiently transparent to the
particular actinic light used.
[0129] A second embodiment of a member which fully supports the
sheet is shown in FIG. 26 generally indicated by the numeral 920.
It comprises a plate of transparent material 930 with a roller 940
at its leading edge free to rotate around its axis. The roller
reduces the effects of friction between the membrane and the plate,
as the greatest force may be at the member's leading edge which is
responsible for pushing material out of the gap between the sheet
101 and the previously formed section of the object 122.
[0130] Another embodiment of a member is shown in FIG. 27 generally
indicated by the numeral 950. It comprises a plate 960 with windows
such as 970 cut in it. The material of construction may be opaque,
such as, for example, stainless steel. The mode of operation of
this member is to support the sheet in one position while light is
projected through the windows of the member, and then the member is
moved to a second position such that the previously obscured
regions of the fabrication area are now exposed and a second
exposure is made through the windows.
[0131] Friction between the member and sheet may be exacerbated by
the presence of moisture or contaminants between the member and the
sheet. This friction can be reduced by adding a substance between
the member and the sheet as indicated by substance 980 in FIG. 34.
The substance may be, for example, a liquid lubricant such as a
mineral or silicon oil, or a powdered solid such as talcum powder.
Powdered metal soaps such as magnesium stearate may be particularly
effective for this purpose. Particles of powder may behave like
tiny ball-bearings and thereby reduce friction. A light dusting of
powder can have a significant friction-reducing effect whilst
having negligible impact on optical transmission through the member
and the sheet.
[0132] FIG. 38 shows a representation of an example tensioner,
opposite sides of which are indicated by numerals 190,191. The
tensioner may be incorporated into a device for making a solid
object, such as, but not limited to, any one of the depicted
embodiments. The tensioner may be used to tension the sheet 101,
keeping it taut. The tensioner is mounted to the chassis of the
apparatus 130. The tensioner includes a frame 192 and a
sheet-contacting component 193 in the form of a ring attached to
the frame. The sheet contacting component is, in use, in contact
with the downwardly facing surface of the sheet 101. The
sheet-contacting component 193 may have any suitable form, such as
square or oval. The parts of the sheet contacting component 193 may
not have sharp edges and corners to prevent puncture or localized
yielding of the sheet 101. The tensioner may comprise one or more
biasing elements that bias the sheet-contacting component towards
the downwardly facing surface of the sheet 101. The one or more
biasing elements may comprise a spring arrangement having extension
springs 194,195, for example, operationally coupled to the sheet
and the frame. In other embodiments, the biasing members may
comprise rubber, extension springs, leaf springs, or any other
suitable biasing means. A hook or grip 196,197 at one end of the
spring 194,195 is hooked over the side wall 106 of the trough or
dish. The other end is attached, hooked or tethered to the frame.
When so placed, the spring, in this but not necessarily all
embodiments, is in tension. The biasing elements may, alternatively
or additionally, comprise electromechanical elements, such as a
motor, or magnets (either electromagnets or permanent magnets). The
downwardly facing surface is also biased into the frame, in this
but not necessarily all embodiments, by gravity. The tensioner may
not, in all circumstances, be sufficient, however, to prevent sag
of the sheet 101 under gravity. A member as described above, such
as 110, may assist in ameliorating any sag.
[0133] The tensioner may alternatively comprise a biasing element
between the sheet 101 and the side wall 106 of the trough or dish.
In this but not necessarily in all embodiments, the tensioner acts
around the perimeter of the sheet thereby maintaining tension in
both the x and y directions.
[0134] The tensioner may prevent the sheet, if not tensioned, from
interfering with the moving member. The tensioner may prevent the
sheet from creasing or being ripped by the moving member.
[0135] The actuator for the member 112, the positioner 120, the
light source, and possibly other parts of the apparatus may be in
communication with and may be controlled by a controller 160 to
coordinate the apparatus to make the object. These and other
components may be connected by wires, cables, wireless, or any
other suitable means. In this embodiment, the controller may have a
processor unit 220, schematically illustrated in FIG. 37. The
processor unit 220 may include a suitable logic device 250 such as,
or similar to, the INTEL PENTIUM or a suitably configured field
programmable gate array (FPGA), connected over a bus 280 to a
random access memory 240 of around 100 Mb and a non-volatile memory
such as a hard disk drive 260 or solid state non-volatile memory
having a capacity of around 1 Gb. The processor has input/output
interfaces 270 such as a universal serial bus and a possible human
machine interface 230 e.g. mouse, keyboard, display etc. Device
components may be controlled using commercially available
machine-to-machine interfaces such as LABVIEW software together
with associated hardware recommended by the commercial interface
provider installed on the processor unit 220, over USB or RS-232 or
TCP/IP links, for example. Alternatively, custom driver software
may be written for improved performance together with custom
printed circuit boards. Alternatively, the processor unit 220 may
comprise an embedded system.
[0136] In this embodiment, the controller 160 is in communication
with another processor which is adapted for determining
instructions and/or information for the device. In alternative
embodiments, the processors are the same processor. An example of
another processing unit comprises a logic device such as, or
similar to, the INTEL PENTIUM or a suitably configured field
programmable gate array (FPGA), connected over a bus to a random
access memory of around 100 Mb and a non-volatile memory of such as
a hard disk drive or solid state non-volatile memory having a
capacity of around 1 Gb. Generally, the configuration may be
similar or identical to that shown in FIG. 37. The processor has a
receiver such as a USB port (or Internet connection, for example)
for receiving information representing a solid object, stored on a
USB FLASH device, for example. The information may be encoded in a
file generated by a Computer Aided Design (CAD) program, the
information specifying the geometry of the object. The
microprocessor runs a decomposer program implementing an algorithm
that decomposes (or transforms) the information into data
indicative of a plurality of sections to be formed sequentially by
the device, the material being used to make the solid object. The
program may have been installed onto the processor from tangible
media such as a DVD or USB memory stick, for example, that stored
the program. In an alternative embodiment, the decomposer may be a
dedicated hardware unit. A series of sections through the object
are determined, each section corresponding to a solid section to be
formed. The sections may then be further processed to represent the
geometry of each section as a rasterised bitmap. The sections or
bitmaps may then used to control the device.
[0137] It will be appreciated that the apparatus and method may be
used to make an object of generally any shape or size, including
jewelry such as rings, prototype car components, micro-components
for precision machines, models for investment casting, and
architectural or design features for a building.
[0138] Now that embodiments of the invention have been described,
it will be appreciated that some embodiments may have some of the
following advantages:
[0139] the flexible element may distort when the solid section and
surfaces are separated, causing the surface to peel away from the
solid section, in which case the object being formed experiences
reduced forces than that generated when separating the section from
the surface by other solid section and/or the object being made is
reduced;
[0140] having the fluid disposed over the surface requires a
relatively modest volume of fluid, reducing costly waste;
[0141] the member supporting the flexible element ameliorates
sagging of the flexible element under the force of gravity, thereby
improving the flatness of the solid sections and reducing
distortions in the object;
[0142] moving the member substantially parallel to the flexible
element requires less force than perpendicular separation of the
member and the flexible element, enabling the making of more
delicate objects.
[0143] moving the member away from beneath the hardened section
prior to separating it from the flexible element allows air to
reach the downward side of the flexible element. This allows the
flexible element to distort freely and facilitate peeling of the
section, whereas atmospheric pressure may prevent free distortion
of the flexible element if the member remains beneath the flexible
element.
[0144] the direction of the force applied by the horizontally
moving member on the flexible member (sheet) is tangential to the
member, and not orthogonal to the member, so that the member may
then tension and take at least some of the force instead of the
force being transferred to the object being made. This may protect
the object from at least some of the force.
[0145] It will be appreciated that numerous variations and/or
modifications may be made to the invention as shown in the specific
embodiments without departing from the spirit or scope of the
invention as broadly described. It is to be noted that while the
above text refers to members being moved by actuators in a linear
fashion, that is, in a straight line, it is to be understood that
the present invention is also applicable to members being actuated
in other ways, such as by rotary action, similar to the manner in
which a car's windscreen wiper operates. The member may in that
case be embodied with a curved edge instead of a straight edge. The
flexible element may not be flat like a sheet, but rather may be
wedged. The downwardly facing surface of the element may be
textured. The present embodiments are, therefore, to be considered
in all respects as illustrative and not restrictive.
[0146] In the claims which follow and in the preceding description
of the invention, except where the context requires otherwise due
to express language or necessary implication, the word "comprise"
or variations such as "comprises" or "comprising" is used in an
inclusive sense, i.e. to specify the presence of the stated
features but not to preclude the presence or addition of further
features in various embodiments of the invention.
[0147] It is to be understood that, if any prior art publication is
referred to herein, such reference does not constitute an admission
that the publication forms a part of the common general knowledge
in the art, in Australia or any other country.
* * * * *