GB2620383A

GB2620383A - Custom moulded composite components and a method of making the same

Info

Publication number: GB2620383A
Application number: GB2209682.0A
Authority: GB
Inventors: Dickson Andrew; Dowling Denis
Original assignee: University College Dublin
Current assignee: University College Dublin
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2024-01-10
Also published as: GB202209682D0

Abstract

A method for manufacturing a customised composite component, the method comprising the steps of fabricating a mould using a three-dimensional printer based on geometric data acquired from a subject or an object, forming a composite preform panel, heating the composite preform panel, transferring the heated composite preform panel to the fabricated mould; and cooling the mould to form the customised composite component. A step of applying pressure to the mould, may be provided using a mechanical, hydraulic, or pneumatic means. The mould may be printed in polymer or metal and the composite preforms may be made from a pre-impregnated sheet, a semi-impregnated sheet or a thermoplastic organosheet. The mould maybe coated with a release agent, and a step of trimming and deburring may be provided. The heating step may be performed by a convection means, an infrared means, or a conduction means. A product may be produced by method and may include, sports, medical or protective equipment.

Description

Custom Moulded Composite Components and a method for making the same

Field of the Invention

The invention relates to a multi-step process for the fabrication of customised composite and multi-material components.

Background to the Invention

The art of fabricating custom moulded composite parts is typically carried out using the following techniques: * Hand Layup -The most frequently used method for manufacturing small batch and/or complex composite parts. The method frequently involves the hand placement of individual fibre sheets into a mould or vacuum bag, which is then placed into an oven or an autoclave to form the final consolidated part. Whilst a human technician can form highly complex components, they are typically expensive, slow, and human error cannot be eliminated from the process. This leads to inconsistent parts that are incapable of being used in highly controlled industries. Cost of computer numerical control (CNC) moulds are still the most prevalent cost in the process.

* Press forming -Press forming is the most economical method for manufacturing flat plates of thermoplastic composite material. The process involves stacking alternating sheets of fabric (reinforcement) and polymer (matrix) into a heated press, then applying heat and pressure to melt the polymer into the fabric. The level of heat and pressure is adjusted based on the polymer. The geometry is limited to flat plates only, but capital costs are relatively low.

* Automated Fibre Placement (AFP) -AFP is an automated method for fabricating composite preforms with a high degree of accuracy, and with the ability to highly tailor the layup of a composite part (fibre orientation, thickness etc). Typically, this utilises a robotic arm or CNC gantry to place a pre-preg composite tape into the desired location onto a mould surface. This forms a preform, which then requires consolidation in an autoclave or an oven.

* Thermoplastic Thermoforming -This method of thermoplastic component manufacture typically utilises thermoplastic sheets (made using press forming), which are heated in an infra-red (IR) or convection oven to near or above the polymer's melting point. Once melted, the heated sheet is placed into a heated mould, and pressure is applied to compress the part into the shape of the mould. These moulds are manufactured from CNC'd aluminium or steel and can include heating units so as to increase the moulds temperature, slowing the cooling of the composite matrix. These systems are used for mass production of panels and small components (car doors, handles, hinges etc), and often incorporate robotics or conveyor systems to reduce manual labour. Capital investment is very high for these systems.

Some of the problems associated with the current techniques is that excessive manual handling and labour are required for composite manufacturing, resulting in low repeatability and inconsistent part quality. Thermoset composite materials are almost impossible to reuse or recycle, resulting in large quantities of waste material in landfill, Thermoplastic composites are reformable and recyclable, but are typically more expensive to process. The high capital cost associated with manufacturing thermoplastic composites makes them difficult to process cost effectively. CNC machined moulds are expensive and take long periods of time to manufacture. They also require heating when used for thermoforming of composites. For small-medium batch manufacturing they are not cost efficient.

It is an object of the present invention to overcome at least one of the above-mentioned problems.

Summary of the Invention

The invention entails a multi-step method for the fabrication of customised composite and multi-material components. In one aspect, the method involves the use of a three-dimensional (3D) printer. The process can be broken down into two main manufacturing steps: Mould fabrication and composite forming.

There is provided a method for manufacturing a customised composite component, the method comprising the steps of: (a) fabricating a mould using a three-dimensional printer based on geometric data acquired from a subject or an object; (b) forming a composite preform panel; (c) heating the composite preform panel; (d) transferring the heated composite preform panel to the fabricated mould; and (e) cooling the mould to form the customised composite component.

In one aspect, in step (c) the composite preform panel is heated to composite melting temperature.

In one aspect, step (d) is performed in less than 20 seconds following completion of step (c). Preferably, step (d) is performed in less than 15 seconds; but ideally between 1-10 seconds. The rapid transfer in step (d) acts to prevent the temperature of the heated composite preform panel falling below its melting temperature.

In one aspect, the geometric data is acquired using a computerized tomography (CT) or a computerized axial tomography (CAT) scan, a magnetic resonance imaging (MRI) scan, a three-dimensional scanner, computer aided design (CAD) scanning, or laser profiling. Preferably, prior to step (a), the acquired geometric data is converted to an editable model to create a positive mould, a negative mould, or both.

In one aspect, following step (d) pressure is applied to the mould. Preferably, the pressure is applied using a mechanical, hydraulic or pneumatic means.

In one aspect, the composite preform panel is heated in step (c) to slightly above the melting point of the composite preform panel.

In one aspect, the mould is printed in a polymer or a metal. Preferably, the polymer and the metal are heat-resistant engineering-grade.

In one aspect, the polymer is a thermoplastic, an elastomer, or a biopolymer.

In one aspect, the metal is selected from stainless steel, cast iron, bronze, graphite, titanium, steel, aluminium, copper, cobalt chrome, tungsten, nickel-based alloys, gold, platinum, palladium, and silver.

In one aspect, the composite preforms are made from a pre-impregnated sheet, a semi-impregnated sheet or a thermoplastic organosheet.

In one aspect, the mould is coated with a release agent to prevent the formed composite preform panel from bonding to the mould.

In one aspect, the method further comprises a step (f) of trimming and deburring the customised composite component when it is removed from the mould.

In one aspect, heating step (c) is performed by a convection means, an infrared means, or a conduction means. Preferably, the infrared heat source emits light at a wavelength of between about 780nm to about 1000pm.

In one aspect, the infrared heat source is selected from a near-infrared heat source, a mid-infrared heat source, or a far-infrared heat source. Preferably, the near-infrared io heat source emits light at a wavelength of between about 780nm to about 2.5 pm.

Preferably, the mid-infrared heat source emits light at a wavelength of between about 2.5 pm to about 5pm. Preferably, the far-infrared heat source emits light at a wavelength of between about 5 pm to about 1000pm.

In one aspect, there is provided a product produced by the method described above.

In one aspect, the product is selected from sports equipment, medical equipment, and protective equipment. In one aspect, the sports equipment is selected from shin guards, arm guards, breast plates, and shoulder pads. In one aspect, the medical equipment is selected from a brace, a support, or a corrective device. In one aspect, the protective equipment is selected from body armour, a guard for a limb or other anatomical item, a shield, a bracing, and the like.

In one aspect, there is provided a computer program comprising program instructions for causing a computer to perform the method described above.

In one aspect, the computer program is embodied on a record medium, a carrier signal, or on a read-only memory.

There is also provided a computer program comprising program instructions for causing a computer program to carry out the above method which may be embodied on a record medium, carrier signal or read-only memory.

The method of the claimed invention imparts several advantages to manufacturing moulded composite components, for example:

S

* The cost of manufacturing small batch (as low as 1 part) thermoplastic composite parts is greatly reduced, thus removing the high costs associated with machined moulds, robotics or conveyor systems.

* The method allows for the mass production of customised composite components for sports, medical, and defence sectors using data collected by a computerized tomography (CT) scan, 3D scan data, etc. * Composite moulds and/or tooling can be rapidly manufactured for conventional composite manufacturing.

* Increased automation in the manufacturing of thermoplastic composites. 10 Definitions In the specification, the term "subject" should be understood to mean a mammal, typically a human, a primate, a farm animal (cow, horse, sheep, goat, pig), a mammal kept in a zoo (elephant, lion, cheetah, zebra, giraffe, and the like). The part of the subject that the geometric data is obtained from is selected from a limb (arm, leg) or a part thereof (hand, foot, finger, toe, thumb, knee, shin, femur), a head or a part thereof (nose, chin, ear, skullcap, cheekbone, eye socket, forehead, neck), a torso (chest, ribs, back), or a combination thereof In the specification, the term "object" should be understood to mean an inanimate object which can be scanned to produce a 3D geometry. Examples of objects may include, but are not limited to the whole or part of, furniture, clothing, machinery, vehicles, buildings, etc. In the specification, the term "preform panel" should be understood to mean a flat panel of thermoformable polymer or composite material which will be heated and pressed into the final geometry of the mould.

In the specification, the term "pre-preg" or "pre-impregnated sheet" should be understood to mean a composite material made from "pre-impregnated" fibres and a partially cured polymer matrix, such as epoxy or phenolic resin, or even a thermoplastic polymer mixed with liquid rubbers or resins. Composite structures built of pre-impregnated sheets will mostly require an oven or autoclave to cure. The main idea behind a pre-impregnated material is the use of anisotropic mechanical properties along the fibres, while the polymer matrix provides filling properties, keeping the fibres in a single system. Fibre sheets are often fiberglass, carbon fibre, or polyparaphenylene terephthalamide (Kev!are).

In the specification, the term "semi-impregnated sheet" is understood to mean a sheet/panel of material that is composed of a polymer matrix material and a fibre reinforcement material whereby the polymer in a powder form is applied (such as by spraying) under heat to the surface of the fibre reinforcement material where it sits and cools into small granules that are bonded onto the fibres, but which is not fully impregnated into material. This form of semi-impregnated sheet is used for ease of storage and handling. To form these semi-impregnated sheets into a finished part, heat and pressure are applied to form the final consolidated/fully impregnated sheet. This may be made from thermoplastic or thermosetting polymers.

In the specification, the term "thermoplastic organosheet" is understood to mean a high-performance, continuous fibre-reinforced composite panel, made of materials such as carbon, poly-paraphenylene terephthalamide (Kevlare), basalt, or glass fibre fabric embedded in a thermoplastic matrix.

In the specification, the term "polymer" should be understood to mean a large molecule (macromolecule) composed of repeating structural units. These subunits are typically connected by covalent chemical bonds. Although the term "polymer" is sometimes taken to refer to plastics, it encompasses a large class comprising both natural and synthetic materials with a wide variety of properties. In the specification, such polymers are any natural or synthetic polymer commonly used in any combination and also as composite materials incorporating particles, nanomaterials, etc.. Such polymers may be a monomer, a copolymer, a homopolymer, a multipolymer, a natural or a synthetic, block copolymers or any material and scaffolds that are extrudable. Such polymers may be thermoplastics, elastomers, or biopolymers.

The term "copolymer" should be understood to mean a polymer derived from two (or more) monomeric species, for example a combination of any two of the below-mentioned polymers. An example of a copolymer, but not limited to such, is PETG (Polyethylene Terephthalate Glycol), which is a PET modified by copolymerization. PETG is a clear amorphous thermoplastic that can be injection moulded or sheet extruded and has superior barrier performance used in the container industry. Other examples include copolymers of propylene and ethylene, Acetal copolymers (Polyoxymethylenes), Polymethylpentene Copolymer (PMP), acrylic and acrylate copolymers, polycarbonate (PC) copolymer, Styrene block copolymers (SBCs) to include Poly(styrene-butadiene-styrene) (SBS), Poly(styrene-isoprene-styrene) (SIS), Poly(styrene-ethylene/butylene-styrene) (SEBS), Ethylene vinyl acetate (EVA), and ethylene vinyl alcohol copolymer (EVOH).

The polymers may be selected from degradable and non-degradable synthetic polymers such as the block copolymers polylactide-block-poly(ethylene glycol)-blockpolylactide (PLA-PEG-PLA) and poly(ethylene glycop-block-polylactide-block-poly(ethylene glycol) (PEG-PLA-PEG) diacrylates, disulfide-containing polyethylene glycol diacrylates (PEG(SS)DA), (hydroxyethyl)methacrylate (HEMA), acrylamide (AAm), acrylic acid (AAc), (N-isopropylacrylamide) (NIPAm), Poly(Nisopropylacrylamide) (PNIPAm) and poly(ethylene glycol) methacrylate (mPEGMA); other synthetic peptide-modified proteins or polysaccharides; poly(vinyl alcohol) (PVA) modified natural polymers.

The term "elastomer should be understood to mean a polymer with viscoelasticity (Le., both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. Examples of an elastomer are, but not limited to, polybutadiene, butadiene and acrylonitrile copolymers (N BR), natural and synthetic rubber, polyesteramide, chloropene rubbers, poly(styreneb-butadiene) copolymers, polysiloxanes (such as polydimethylsiloxane (PDMS) (or silicone oil)), polyisoprene, polyurethane, polychloroprene, chlorinated polyethylene, polyester/ether urethane, polyurethane, polyethylene propylene, chlorosulphanated polyethylene, polyalkylene oxide, flurosilicone, highly saturated nitrile (HSN, HNBR), nitrile, polyacrylate, silicone, fluorinated ethylene propylene (FEP), a perfluoroelastomer, a fluroelastomer, a copolymer of tetrafluoroethylene/propylene, carboxylated nitrile, a dipolymer of hexafluoropropylene and vinylidene fluoride, and mixtures thereof The term "thermoplastic" should be understood to mean a type of plastic made up of polymer resins that softens when heated and hardens when cooled. Examples of a thermoplastic include acrylonitrile butadiene styrene, polypropylene, polyethylene, polyvinylchloride, polyamide, polyester, acrylic, polyacrylic, polyacrylonitrile, polycarbonate, ethylene-vinyl acetate, ethylene vinyl alcohol, polytetrafluoroethylene, ethylene chlorotrifluoroethylene, ethylene tetrafluoroethylene, liquid crystal polymer,

S

polybutadiene, polychlorotrifluoroehtylene, polystyrene, polyurethane, polyester resin, polysulfide, polyvinyl alcohol, polyvinyl chloride emulsion, polyvinylpyrrolidone, silicone, styrene acrylic copolymer, dichloromethane, cyanoacrylate, and polyvinyl acetate.

In one aspect, the printed nanocomposite material is coated with a polymer, a thermoplastic, an elastomer, a copolymer, or a combination thereof, to encapsulate an object being printed. An example of the polymers that can be used are listed above, and also include, for example, an encapsulating polymer such as an acrylate copolymer, or a silicone-based copolymer.

The term "biopolymer should be understood to mean natural polymers produced by the cells of living organisms. Biopolymers consist of monomeric units that are covalently bonded to form larger molecules, such as, but not limited to, gelatin, lignin, cellulose, polyalkylene esters, polyvinyl alcohol, polyamide esters, polyalkylene esters, polyanhydrides, polylacfide (PLA) and its copolymers, and polyhydroxyalkanoate (PHA).

The term "metal" should be understood to mean metal powder or sheets of metal that can be used in the 3D printing process. Examples of such metals include, but are not limited to, stainless steel (for example, 316L and 17-4 PH stainless steel), cast iron, bronze, graphite, titanium, steel (for example, A2, 02, and H13 Tool Steel), aluminium, copper, cobalt chrome, tungsten, nickel-based alloys (for example, Inconel 625, Inconel 718), gold, platinum, palladium, and silver.

The term "composite", "composite material", or "polymer composite" should be understood to mean a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements. Within the finished structure, the individual elements remain separate and distinct, distinguishing composites from mixtures and solid solutions. Examples of such composites include a mixture of a polymer and a metal, carbon fibre-epoxy composites, glass fibre-epoxy composites, carbon fibre-polyamide composites, carbon fibrepolycarbonate composites, and carbon fibre-PEEK composites. Natural fibre thermoset and thermoplastic composites such as flaxfibre-epoxy composites, bamboo-epoxy composite, hemp fibre-epoxy composites, flax fibre-polycarbonate composites, and the like, can also be used.

In the specification, the term "infrared (IR)" should be understood to mean electromagnetic radiation (EMS) with wavelengths longer than those of visible light. IS is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz).

Longer IS wavelengths (30pm-100pm) are sometimes included as part of the terahertz radiation range.

In the specification, the term "release agent" should be understood to mean a lubricant that prevents the surface of the composite preform from bonding to the mould and allows the finished product to be removed safely without damaging the finish or product. Examples of release agents are silicone, polyvinyl alcohol (PVA), and polytetrafluoroethylene (PTFE).

In the specification, the term "trimming and deburring" should be understood to mean the act of removing the extra materials and smoothing the cut or sharp edges, or burrs, of the moulded customised composite component, leaving the component with smooth edges.

In the specification, the term "corrective device" should be understood to mean a device that can be used to correct skeletal structures which may have defects or damage, such as curved spines and broken limbs.

Brief Description of the Drawings

The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:-Figure 1 is an image depicting the stages of a typical forming procedure. (top right) a 3D printed mould produced from 3D scan data of a human shoulder. (Centre) A composite component after thermoforming and before trimming of excess material.

(Bottom Left) The composite shoulder guard, trimmed and coated in a fabric layer for use in sports.

Figure 2 is an image of the concave side of a shoulder guard of Figure 1 (bottom left article) without the fabric applied and formed using an anatomically derived mould formed by the method of the claimed invention. The curves of the guard match that of the subject exactly and are unique to the individual.

Figure 3 is an image depicting the convex side of the shoulder guard of Figure Figure 4 is an image depicting a thermoformed composite plate before removal from an anatomically derived female mould which was formed by the method of the claimed invention.

Detailed Description of the Drawings

The claimed invention is directed to a method of manufacturing customised composite and multi-material components. The method begins with geometry acquisition, in which a source of geometry (person, object, etc.) is captured (using Computer Aided Design (CAD), 3D scanning, Profiling, etc.) and is converted into an editable model (mesh, solid, or surface). This editable model can then be modified to form the positive and/or negative moulds required to form the required composite geometry.

After the moulds are designed, they are 3D printed in a heat resistant engineering grade polymer or metal. This may include, but not limited to, PEI (polyetherimide), PEEK (polyetheretherketone), steel or aluminium. These moulds can be used as they are, or they may be finished via CNC to achieve a higher level of surface polish.

Whilst the moulds are being manufactured, the composite panel can be designed and laminated. This process begins by importing the target geometry from the 3D scan and flattening the 3D shape onto a 2D surface. It is also typical to add additional material for gripping and alignment of the materials. The target composite shape can then be 3D printed, CNC, or laser cut (when using premanufactured preform sheets). These composite preformed sheets may be made from a preimpregnated sheet, a semi-impregnated sheet, a thermoplastic organosheet material, or a combination thereof. It is also possible to utilise heat activated thermosetting pre-impregnated sheets in this process.

The printed mould and the composite panel are then transferred to a heating stage for forming. The mould halves are coated in a release agent or coating, which prevents the formed composite from bonding to the mould. The composite preform is attached to a frame which suspends it either under an IR heating source, a convention heat source, or within a convection oven until the material is evenly heated throughout to the target forming temperature (typically slightly above the melting point of the thermoplastic matrix). The composite preform is then rapidly transferred (typically, no more than 20 seconds; preferably less than 15 seconds; but ideally between 1-10 seconds) between the two moulds to minimise temperature loss, and the moulds pressed together, sandwiching the heated panel into the desired shape (this pressing may be assisted with pneumatic or hydraulic pressure if required). After allowing the mould to cool for a suitable period of time (materials dependent), the moulds are separated, and the composite form removed (demoulded).

Referring now to the figures, where Figure 1 illustrates three stages of manufacturing of a custom composite component for a human shoulder. The 3D printed temperature resistant mould is shown top right in grey, which is derived from a 3D scan of a human shoulder. This is used to form the heated composite panel into the desired geometry. The thermoformed composite component is shown centre after removal from the mould. The components is then cleaned and trimmed to the final shape, before being coated in a fabric protective layer (optional) shown in white in the bottom left.

Figure 2 and Figure 3 show concave and convex sides of a finished individualised carbon fibre composite component produced by the method of the claimed invention. The part was formed using a 3D scan of a human shoulder, which was converted into a 3D printable format. The part was then 3D printed using a temperature resistance material. A sheet of pre-impregnated thermoplastic composite was then cut to size and heated to above the melting point of the thermoplastic composite. Finally, the heated pre-impregnated composite sheet was quickly transferred and pressed between male and female moulds to acquire the required geometry. After a brief cooling period the moulded composite part is removed and trimmed of excess material.

Figure 4 shows a thermoformed composite plate before removal from an anatomically derived female mould. The male mould (not shown) and female mould are formed from a 3D scan of a subject's anatomy or an object. The moulds are 3D printed from a temperature resistant polymer to ensure that the heat from the composite material does not deform the moulds geometry, rendering the mould inaccurate. The mould in this case also has a coating applied to ensure that the composite part does not adhere to the mould and can be easily removed after cooling.

The embodiments in the invention described with reference to the drawings comprise a computer apparatus and/or processes performed in a computer apparatus. However, the invention also extends to computer programs, particularly computer programs stored on or in a carrier adapted to bring the invention into practice. The program may be in the form of source code, object code, or a code intermediate source and object code, such as in partially compiled form or in any other form suitable for use in the implementation of the method according to the invention. The carrier may comprise a storage medium such as ROM, e.g. CD ROM, or magnetic recording medium, e.g. a memory stick or hard disk. The carrier may be an electrical or optical signal which may be transmitted via an electrical or an optical cable or by radio or other means.

In the specification the terms "comprise, comprises, comprised and comprising" or any variation thereof and the terms "include, includes, included and including" or any variation thereof are considered to be totally interchangeable and they should all be afforded the widest possible interpretation and vice versa.

The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail.

Claims

Claims 1. A method for manufacturing a customised composite component, the method comprising the steps of: (a) fabricating a mould using a three-dimensional printer based on geometric data acquired from a subject or an object; (b) forming a composite preform panel; (c) heating the composite preform panel; (d) transferring the heated composite preform panel to the fabricated mould; and (e) cooling the mould to form the customised composite component.
2. The method of Claim 1, wherein in step (c) the composite preform panel is heated to composite melting temperature.
3. The method of Claim 1 or Claim 2, wherein step (d) is performed in less than 20 seconds following completion of step (c).
4. The method of any one of Claims 1 to 3, wherein the geometric data is acquired using a computerized tomography (CT) or a computerized axial tomography (CAT) scan, a magnetic resonance imaging (MRI) scan, a three-dimensional scanner, computer aided design (CAD) scanning, or laser profiling.
5. The method of Claim 4, wherein prior to step (a), the acquired geometric data is converted to an editable model to create a positive mould, a negative mould, or both.
6. The method of any one of the preceding claims, wherein following step (d) pressure is applied to the mould.
7 The method of Claim 6, wherein the pressure is applied using a mechanical, hydraulic or pneumatic means.
8. The method of any one of the preceding claims, wherein the composite preform panel is heated in step (c) to slightly above the melting point of the composite preform panel.
9. The method of any one of the preceding claims, wherein the mould is printed in a polymer or a metal.
10. The method of Claim 9, wherein the polymer and the metal are heat-resistant engineering-grade.
11. The method of Claim 9 or Claim 10, wherein the polymer is a thermoplastic, an elastomer, or a biopolymer.
12. The method of Claim 9 or Claim 10, wherein the metal is selected from stainless steel, cast iron, bronze, graphite, titanium, steel, aluminium, copper, cobalt chrome, tungsten, nickel-based alloys, gold, platinum, palladium, and silver.
13. The method of any one of the preceding claims, wherein the composite preforms are made from a pre-impregnated sheet, a semi-impregnated sheet or a thermoplastic organosheet.
14. The method of any one of the preceding claims, wherein the mould is coated with a release agent to prevent the formed composite preform panel from bonding to the mould.
15. The method of any one of the preceding claims, further comprising the step (f) of trimming and deburring the customised composite component when it is removed from the mould.
16. The method of any one of the preceding claims, wherein heating step (c) is performed by a convection means, an infrared means, or a conduction means.
17. The method of Claim 16, wherein the infrared heat source emits light at a wavelength of between about 780nm to about 1000pm.
18. The method of any one of Claims 16 or 17, wherein the infrared heat source is selected from a near-infrared heat source, a mid-infrared heat source, or a far-infrared heat source.
19. The method of Claim 18, wherein the near-infrared heat source emits light at a wavelength of between about 780nm to about 2.5 pm.
20. The method of Claim 18, wherein the mid-infrared heat source emits light at a wavelength of between about 2.5 rim to about 5ttm.
21. The method of Claim 18, wherein the far-infrared heat source emits light at a wavelength of between about 5 i_tm to about 1000pm
22. A product produced by the method of any one of the preceding claims.
23. The product of Claim 22 selected from sports equipment, medical equipment, and protective equipment.
24. The product of Claim 23, wherein the sports equipment is selected from shin guards, arm guards, breast plates, and shoulder pads; wherein the medical equipment is selected from a brace, a support, or a corrective device; and wherein the protective equipment is selected from body armour, a guard for a limb or other anatomical item, a shield, a bracing, and the like.