WO2014188216A1

WO2014188216A1 - Device and method for creating three-dimensional products

Info

Publication number: WO2014188216A1
Application number: PCT/GB2014/051598
Authority: WO
Inventors: David FEINTRENIE
Original assignee: W0O0T Limited
Priority date: 2013-05-24
Filing date: 2014-05-23
Publication date: 2014-11-27
Also published as: GB201309443D0

Abstract

Device and method for creating three-dimensional products A device for creating a three-dimensional product, comprising a planar build platform (5,105,211) for supporting the product, a print head (7) for dispensing a substance (13) for creating the three- dimensional product, and a laser (1,101Α, 101B,101C) for providing a laser beam (3,103) for irradiating the substance for creating the three-dimensional product, wherein in use the laser beam (3,103) is parallel to the plane of the build platform (5,105,211). The product is created through providing sequential layers of the substance. The laser beam (3,103) is parallel to the layer of the product being created.

Description

Device and method for creating three-dimensional products Field of the Invention The present invention relates to a device for creating three-dimensional products, and a method of creating a three-dimensional product.

Background of the Invention Additive manufacturing or three-dimensional (3D) printing is a process of making a three- dimensional object. Successive layers of material are laid down to form the object. A number of different additive processes are currently known, including fused deposition modelling stereolithography, and selective laser sintering. Fused deposition modelling involves melting a material and spreading it on a platform to build a three-dimensional product layer by layer.

Stereolithography involves directing light from a digital light processing projector towards certain parts of a pool of liquid polymer to harden specific points of the polymer.

Inkjet printer systems spray photopolymer materials onto a build tray in layers. Each layer is cured with UV light after it is jetted.

Selective laser sintering involves beaming a laser onto a bed of plastic or metal powder whereby select points of the plastic or metal are bound together. A disadvantage of this method is the waste of powder material since around 20% of the powder material is wasted.

In 3D printing techniques which involve a print head and a laser, the laser beam is at an angle relative to the layer of the product which is being created or, in other words, the laser beam is not parallel to the layer of the product which is being created. There is a high degree of precision required in ensuring that the laser is directed to the desired point.

Known apparatus can be slow to print. Known apparatus for 3D printing is expensive.

Summary of the Invention The present invention aims to overcome the abovementioned drawbacks of prior art devices, and other drawbacks not explicitly mentioned herein.

According to a first aspect of this disclosure, there is provided a device for creating a three- dimensional product, comprising a planar build platform for supporting the product, a print head for dispensing a substance for creating the three-dimensional product, and a laser for providing a laser beam for irradiating the substance for creating the three-dimensional product, wherein in use the laser beam is parallel to the plane of the build platform. The substance may be a polymer, preferably a liquid polymer.

The print head may be a polymer dispensing print head for dispensing a polymer, preferably a liquid polymer. The substance for creating the product may comprise a polymer. The substance may comprise a liquid polymer for example any liquid polymer which is cured by laser light. The polymer may be, for example, Objet TangoBlack, Objet Fullcure 720, Objet Vero, or Transparent Resin Spot-HA.

The substance may include metals such as stainless steel, tool steel, cobalt-chrome, aluminium, titanium, gold, platinum, brass and silver. The metals may be provided in powder form and may be in a blend specifically made for 3D printing.

The substance may include silicon, sand, glass, concrete, carbon, ceramic, PLA, ABS, Duraform SLS, sugar, salt.

The substance may include graphene ink, for example Vor-ink. The substance may include medicine, for example liquid medicine which hardens upon exposure to heat provided by a laser. The substance may include wood resin. The substance may include food, such as chocolate, pasta, meat, bread, cheese.

The or each laser will have a wavelength and a power rating which are suitable for curing/melting/fusing/partially melting or in other ways developing the substance dispensed from the first print head for creating the product. Lasers with a wavelength of 180-315 nm (UV-B, UV-C) and 315-405 nm (UV-A) with an output inferior to 500MW can be used to cure resin. Lasers with a wavelength of 1.4 to 3.0 μιη (I R) and 3.0μιτι to 1 mm (IR) with an output superior to 500 W can be used to melt metal powder. The print head may spray the substance in a spray direction, and the print head may be arranged so that the spray direction is substantially perpendicular to the laser beam in use.

The device may further comprise a second print head for dispensing a second substance for creating the three-dimensional product.

The second print head may spray the second substance in a spray direction, the spray direction of the second print head being parallel to the spray direction of the first print head. The device may further comprise at least one colour print head for providing a colour substance, wherein the at least one colour print head is arranged to spray the colour substance to converge with the substance dispensed from the first print head.

The device may further comprise a spreading means for spreading the laser beam into a plane, wherein the spreading means is arranged so that in use the laser beam is spread into a plane which is parallel to the build platform.

The device may further comprise a second laser for providing a second laser beam for irradiating the substance for creating the three-dimensional product, the second laser being arranged so that its laser beam is parallel to the plane of the build platform.

The device may comprise a second spreading means for spreading the second laser beam into a plane, wherein the second spreading means is arranged so that in use the second laser beam is spread into a plane which is parallel to the build platform.

The device may comprise a third laser for providing a third laser beam for irradiating the substance for creating the three-dimensional product, the third laser being arranged so that its laser beam is parallel to the plane of the build platform. The device may comprise a third spreading means for spreading the third laser beam into a plane, wherein the third spreading means is arranged so that in use the third laser beam is spread into a plane which is parallel to the build platform.

Having at least three lasers, each having a laser spreading means associated therewith, advantageously creates a surface of laser light that can reach any droplet of substance dispensed from the print head wherever it falls within the area defined by the build platform. If the print head is printing with a polymer material then having at least three lasers advantageously improves the speed at which polymerization occurs. Increasing the number of lasers can increase the efficiency of the device. If the print head is printing with a liquid polymer and three lasers are provided, each having a laser spreading means associated therewith, then each laser may have a wavelength of 180-315 nm or 315-405 nm and a power output inferior to 500MW.

The first laser, the second laser and the third laser may be spatially arranged to form the corners of an equilateral triangle.

The or each spreading means may be a lens. The or each lens may be a powell lens.

The device may further comprise a laser directing means for directing the laser beam to a plurality of different locations in a plane which is parallel to the build platform.

The device may further comprise a print head moving means for moving the print head.

The print head moving means may comprise a delta arm.

The device may further comprise a build platform moving means for moving the build platform. The build platform moving means may be arranged to move the build platform in a direction which is perpendicular to the plane of the build platform.

The build platform moving means may comprise at least one screw and a stepper motor. Each screw is preferably a lead screw.

The device may further comprise a laser moving means for moving the or each laser between a first layer creating position in which the laser beam of the or each laser is parallel to the build platform, and a second layer creating position in which the laser beam of the or each laser is parallel to the build platform.

The laser moving means may comprise at least one screw and a stepper motor. Each screw is preferably a lead screw.

The laser moving means and the print head moving means may be distinct modules which permits the or each laser and the print head to be moved at a faster speed than in prior art apparatus in which the laser moving means and the print head moving means are combined in a single heavier module. This further advantageously permits a higher resolution for the print since there is room for a larger print head with more nozzles.

The device may comprise at least one camera for imaging the product. The device may comprise at least three cameras for imaging the product. The device may comprise at least fifteen cameras for imaging the product.

The print head may comprise a first nozzle for dispensing a substance for creating a first layer of the three-dimensional product, and at least a second nozzle for dispensing a substance for creating a second layer of the three-dimensional product on top of the first layer.

The print head may comprise a third nozzle for dispensing a substance for creating a third layer of the three-dimensional product on top of the second layer. According to a second aspect of the disclosure, there is provided a method of creating a three- dimensional product, comprising creating a layer of the product by depositing a substance from a print head onto a laser beam, wherein the laser beam is parallel to the layer being created.

The method may further comprise moving the print head along an axis to create a first line of the product.

The method may further comprise displacing the print head perpendicular to the axis.

The method may further comprise creating a second line of the product which is parallel to the first line.

The method may further comprise moving the laser beam from a first position to a second position and moving the print head so that the product is deposited onto the laser beam at the second position.

The method may further comprise providing a laser spreading means for spreading the laser beam into a plane which is parallel to the layer being created.

The method may further comprise providing a second laser and a second laser spreading means for spreading the second laser beam into a plane which is parallel to the layer being created, and a third laser and a third laser spreading means for spreading the third laser beam into a plane which is parallel to the layer being created. The method described herein may comprise using the device as described herein. Brief Description of the Drawings

The foregoing and other objects, features and advantages of the invention will be apparent from the following description and drawings, in which:

Figure 1 is a perspective view illustrating components of a device operating in accordance with the present invention;

Figure 2 is a plan view illustrating the device of Figure 1 operating in accordance with the present invention; Figure 3 illustrates a laser moving means in accordance with an embodiment of the present invention;

Figure 4 is a side view illustrating the laser beam being parallel to the build platform and incident on the layer being created;

Figure 5 is a plan view illustrating operation of an alternative device in accordance with the present invention;

Figure 6 is a perspective view of details shown in Figure 5;

Figure 7 is a perspective view illustrating operation of a further embodiment of the present invention;

Figure 8 is a diagram illustrating movement of a print head in accordance with the present invention;

Figure 9 is a diagram illustrating an alternative movement of a print head in accordance with the present invention; Figure 10 is a cross-sectional view of details of a print head in accordance with the present invention; Figure 11 is a perspective view showing components of a device of the present invention; Figure 12 illustrates the driving gears which are used in Figure 11 and other embodiments; Figure 13 shows detail of colour printing;

Figure 14 is a plan view of a further embodiment; Figure 15 is a plan view of a further embodiment; and

Figure 16 is a side view of a further embodiment. Detailed Description In the following sections detailed descriptions of embodiments of the invention are given. The description of both preferred and alternative embodiments though thorough are exemplary embodiments only, and it is understood that variations, modifications and alterations may be apparent. It is therefore to be understood that said exemplary embodiments do not limit the broadness of aspects of the underlying invention.

Figure 1 illustrates operation of a device for creating a three-dimensional product. The device comprises a build platform 5, which has a planar upper surface in a plane defined by an x-axis and an orthogonal y-axis. A z-axis is defined, being perpendicular to the x-axis and the y-axis. The build platform 5 can be raised or lowered by a build platform moving means (not shown). The build platform 5 is moved along the z-axis by the build platform moving means. The build platform moving means may comprise at least one screw and a stepper motor. Preferably the build platform moving means comprises three screws and a stepper motor, as described in more detail in relation to figures 11 and 12. Each screw is preferably a lead screw. A laser 1 provides a laser beam 3 in use. The laser is arranged so that when the laser is turned on, a working part of the laser beam 3 is substantially parallel to the plane of the build platform. The working part of the laser beam is the part of the beam which irradiates the substance dispensed from the print head. A laser-moving means (not shown) is provided for raising or lowering the laser 1. The laser is moved by the laser-moving means along the z-axis. The laser- moving means may comprise at least one screw and a stepper motor. Preferably the laser-moving means comprises three screws, as described in more detail in relation to figures 11 and 12. Each screw is preferably a lead screw. A laser directing means 21 is provided for directing the laser beam 3 to a plurality of different locations in a plane which is parallel to the build platform. Figure 2 shows the laser beam 3A in a first position in which it is directed towards the substance 13A at a first point in the layer being created, and the laser beam 3B in a second position in the second position in which it is directed towards the substance 13B at a second point in the same layer being created.

In Figures 1 and 2, the laser moving means rotates the laser beam about an axis which is perpendicular to the build platform 5. In an alternative embodiment shown in Figure 3 the laser 1 and the print head 7 are mounted on a common moving means 8 so that the laser 1 and the print head 7 translate together along an axis. In Figure 3, this axis is the y-axis. This ensures that the laser beam 3 is always positioned inline with the substance 13 dispensed from the print head 7. The print head 7 is free to move on the common moving means along a second axis. In Figure 3, the second axis is the x-axis. This allows the print head to print lines at multiple points on the x- axis.

A laser shield 9 is provided for blocking the laser beam, as shown in figure 1. This prevents the laser beam 3 from having effects outside of the device. The laser shield 9 may be a coating. The coating 9 may be made from a number of materials, for example steel or tungsten. A steel coating is particularly appropriate if the laser is being used to melt plastic, and the tungsten coating is particularly appropriate if the laser is being used to melt metal.

A first print head 7 is provided for dispensing a substance 13 for creating the three-dimensional product. The print head 7 sprays the substance 13 towards the build platform 3. The substance 13 may be dispensed by gravity. If the print head is dispensing a powder then the powder may be sprayed with compressed air. A print head moving means (not shown) is provided for moving the print head in the x-y plane. The print head moving means may additionally move the print head along the z-axis. The print head moving means may comprise delta arms. The print head moving means moves the print head in lines to dispense the substance to form the layers of the product. The dispensed material is developed when the laser beam 3 is shone on it. Reference numeral 15 indicates already developed substance. Developing may include curing, melting, partially melting or hardening depending on the nature of the substance creating the 3D product.

The substance may be a powder. The laser melts or partially melts the powder on contact therewith. Figure 4 is a side view illustrating the laser beam 3 being parallel to the build platform 5 and incident on the layer of the substance 13 being created. In an alternative embodiment, a plane of laser light may be provided, as described below in more detail in relation to figures 5 and 6. In this case, the laser light may be incident on the substance 13 from multiple directions.

The laser beam or plane in the embodiments shown in Figures 5 and 6 may have a height which is greater than the height of a single layer of the substance being printed. The laser beam or plane is thus incident on two or more layers of the substance. . Figures 8 and 9 indicate possible paths 315 for the print head. Both figures show paths which involve printing in successive lines or swaths. The print head may spray in a way that wherever the substance lands, it will be hit by the laser light.

The device may further comprise a second print head (not shown) for dispensing a second substance for creating the three-dimensional product. The second substance may be different to the first substance. The first and second print heads may dispense the materials in parallel directions so that the materials do not converge prior to being deposited on the layer being created. It may be desired to add colour to the substance dispensed from the first print head 7. In this case, at least one colour print head may be provided (see Figure 13). The or each colour print head is arranged around the first print head 7 to spray a colour substance to converge with the substance dispensed from the first print head 7. The first print head may dispense a droplet of the substance onto the layer being created and the coloured ink may be sprayed onto the droplet. The colour substance may converge with the substance 13 dispensed from the first print head 7 before the substance is irradiated by the laser light. Colour print head nozzles 14 spray ink 18 to converge with the substance 13 dispensed from the first print head 7. Five colour print head nozzles 1 may be provided to each spray one of the following colours: red, blue, yellow, black, white. It may be necessary to turn off the laser beam or beams for a short period of time whilst the colour substance and the substance dispensed from the first print head blend together. After blending, the laser beam or beams can be turned back on. The lasers may be turned on and off automatically as instructed by the program or other means for instructing the device to make the product. A colour cartridge using inkjet technology may push ink down a tube, preferably a nylon tube, to the print head.

The arrangement described above in relation to the colour print head nozzles can be used to spray different metal powders instead of different colours. The printer can thus create alloys with specific percentages of metal composition through mixing the different metal powders. The device may be controlled via a computer which is programmed to control the mixing of the powders and the creation of the product. In operation of the embodiments shown in figures 1 ,2 and 3, a first layer of the product is created on the build platform 5. The print head 7 dispenses the substance 13 onto the build platform 5. The laser beam 3 is parallel to the build platform 5 and incident on the substance when it lands on the build platform. The laser-directing means 21 directs the laser beam 3 to the location at which the substance 13 lands on the build platform. The substance 13 hardens or otherwise develops when it meets the laser beam 3. The print head 7 moves to dispense the substance 13 at a second location on the build platform 5. The laser-directing means directs the laser beam 3 to the second location so that the laser beam 3 is always positioned where the substance 13 lands on the build platform. Upon completion of the first layer, the second layer is created on top of the first layer.

The build platform 5 and the laser 1 are moved relative to one another so that the laser beam 3 is in position to harden the material forming the second layer. This may involve one or more of moving the build platform 5 along the z-axis with the build platform moving means and moving the laser 1 with the laser-moving means along the z-axis. In a preferred embodiment, the laser 1 is stationary and it is the build platform 5 which is moved along the z-axis so that the laser beam 3 is in position to harden the material forming the second layer.

The second layer of the product is created on top of the first layer. The second layer of the product is created in substantially the same way in which the first layer of the product is created except the second layer is created on top of the first layer instead of on the build platform. Subsequent layers may be created on top of each previous layer until the product is complete.

Instructions for making the product are communicated to the device for instructing the movement of the print head, the activation of the laser or lasers and movement of the build platform. The instructions may be input and communicated to the device via a computer.

Figure 5 shows an alternative embodiment which functions in a substantially similar way to the embodiment shown in Figures 1 to 4, except instead of having a collimated laser beam for developing the substance, a plane of laser light is provided for developing the substance. Figure 6 is a perspective view of an arrangement in which a plane of laser light is provided for hardening the substance. In this embodiment, the substance may be a polymer, in particular a liquid polymer. The laser light cures the polymer. The lasers may be ultraviolet or blue lasers. The lasers may each have a power output which is equal to or less than 500MW. A preferred wavelength for the lasers is 180 to 405 nm. A preferred power output is 50MW.

Three lasers 101 A, 101 B, 101 C are provided and each laser has a lens 117 located in the path of its emitted laser beam. The lens 1 17 spreads its associated laser beam into a plane of laser light 103. The outer extents of the spread light from the lens 117 are shown by reference numbers 103A and 103B for the laser 101 A. The lens 117 may be a powell lens or a cylinder lens. The plane of laser light is parallel to the build platform 105. The plane of laser light is incident on the layer of the substance being created. The three lasers 101 A, 101 B, 101C are, in one embodiment, spatially arranged to form the corners of an equilateral triangle.

The build platform 105, has a planar upper surface in a plane defined by an x-axis and an orthogonal y-axis. A z-axis is defined, being perpendicular to the x-axis and the y-axis. The build platform 5 can be raised or lowered by a build platform moving means (not shown). The build platform 5 is moved by the build platform moving means along the z-axis. The build platform moving means may comprise at least one screw and a stepper motor. Preferably, the build platform moving means comprises three screws and a stepper motor, as described in more detail in relation to figures 1 1 and 12. The three screws may be spatially arranged in an equilateral triangle on the outer edges of the build platform. Each screw is preferably a lead screw.

A laser-moving means (not shown) is provided for raising or lowering the or each laser 101 A, 01 B, 101 C. The laser is moved by the laser-moving means along the z-axis. The laser-moving means may comprise at least one screw and a stepper motor. Preferably, the laser-moving means comprises three screws and a stepper motor, as described in more detail in relation to figures 11 and 12. The three screws may be spatially arranged in an equilateral triangle. Each screw is preferably a lead screw.

A first print head is provided for dispensing a substance 13 for creating the three-dimensional product, as described above in relation to Figures 1 to 4. The device may further comprise a second print head (not shown) for dispensing a second substance for creating the three-dimensional product, as described above in relation to figures 1 to 4. It may be desired to add colour to the substance dispensed from the first print head, and this can be achieved as described above in relation to figures 1 to 4 and 13.

As an alternative to the embodiment shown in Figures 5 and 6, it is possible to provide only one or two of the lasers 101 A, 101 B, 101 C, and their associated laser beam spreading means 117. In this alternative embodiment, the or each laser may be able to move relative to the build platform 105 so that the or each laser beam can be optimally positioned. Alternatively, a full circle of lasers may be provided or sufficient lasers to provide enough power to cure the polymer dispensed from the print head. The light may be incident on the substance from multiple directions. In operation of the embodiment shown in figures 5 and 6, a first layer of the product is created on the build platform 105. The print head dispenses the substance 13 onto the build platform 105. The laser plane 103 is parallel to the build platform 105. Laser light in the laser plane 103 is incident on the layer of the product being created. Since the laser energy is spread over an area, the substance 13 will always meet a portion of the laser beam wherever it lands on the build platform. Meeting the laser beam causes the substance 13 to harden or cure or otherwise develop. The print head moves to dispense the substance 13 at a second location on the build platform 105. The substance will again meet the laser plane. The print head continues to move to print the first layer. Upon completion of the first layer, the second layer is created on top of the first layer. The build platform 105 and the lasers 101A, 101 B, 101C are moved relative to one another so that the laser plane 103 is in position to harden the material forming the second layer. This may involve one or more of moving the build platform 105 along the z-axis with the build platform moving means and moving the lasers 101 A, 101 B, 101 C with the laser-moving means along the z-axis. In a preferred embodiment, the lasers 101A, 101 B, 101 C are stationary and it is the build platform 105 which is moved along the z-axis so that the laser plane 103 is in position to harden the material forming the second layer.

The second layer of the product is created on top of the first layer. The second layer of the product is created in substantially the same way in which the first layer of the product is created except the second layer is created on top of the first layer instead of on the build platform. Subsequent layers may be created on top of each previous layer until the product is complete. Once all of the layers or at least some of the layers of the product have been formed, the plane of laser light may be shone onto one or more of the layers of the product to partially melt the outermost edges and give a smoother finish to the product. The lasers 101 A, 101 B, 101 C and their associated lenses may be moved along the z-axis to shine the light onto the one or more layers of the product. The intensity of light emitted by the lasers may be increased or decreased during this smoothing process. The power of the laser may be less than 500mW whilst the layers are being created. During the smoothing process the intensity of the laser may be increased to above 500mW.

For each of the embodiments of Figures 1 to 6, and in other embodiments of the present invention, the device may comprise one or more cameras. The cameras may be mounted above the laser or lasers. Preferably, at least three cameras are provided which are spatially arranged in an equilateral triangle. Preferably, enough cameras are provided to image the entire product. If the laser build platform has a diameter of 22 cm, then fifteen cameras are provided, mounted in a circle above the laser or lasers. The cameras may be used to scan objects that the computer has no 3D data of. The cameras may capture the object in a particular file format, such as jpeg, and converted into a 3D model format such as CAD or STL. The cameras may simultaneously take a photograph of the product from different angles. The cameras may record the creation of the product. The or each camera may capture video of the creation of the product. Data captured by the or each camera may be sent to software that uses the data to create a colour three- dimensional model of the product. Figure 11 shows three cameras 235.

Figure 7 shows detail of an alternative device in accordance with the present invention. In this arrangement, a mirror 302 is used to deflect the laser beam 303 of the laser 301 through an angle, for example 90°, so that at least a working part of the laser beam is parallel to the plane of the build platform 305. As in the previous embodiments, a print head 307 is provided for dispensing a substance 3 3 for creating the product. A laser beam spreading means (not shown), for example a powell lens, may be provided to spread the reflected laser beam into a plane which is parallel to the plane of the build platform.

Figure 10 is a close up view of a print head for dispensing a liquid polymer for embodiments of the present invention. A liquid polymer cartridge 204 is provided, along with colour ink cartridges 206 around the polymer cartridge 204. There is one colour ink cartridge 206 for each colour. There may be five colour ink cartridges, each dispensing a different colour (red, yellow, blue, black and white). A nylon tube 208 may transport the each colour ink from its respective cartridge to the point of dispersion. The print head module 210 is shown in further detail in figure 13. Figure 10 shows a delta arm 202 for moving the print head, and a stepper motor 203 to operate the delta arm. Figure 10 illustrates the build platform 105 and the plane of laser light 103 from the lasers 101A, 101 B, 101 C.

The height of the print head nozzle above the layer being created will depend on the height input to the software. For example, the height may be 1 micron or 100 microns.

Figure 1 1 shows details of an embodiment of the invention, which may utilize a plane of light, as described above in relation to figures 5 and 6 for hardening the substance. The device 2 has an outer casing 4, preferably made of glass, and a lower casing 42. Three lasers and their associated spreading means are mounted on a laser mount 201 in the form of a ring. The lasers are preferably equally spaced around the laser mount. A camera 235 is mounted above each laser. The laser mount 201 is located in the casing 4, along with the build platform 211. Three pillars 227 are provided on the exterior of the casing 4 for structural support. The pillars 227 are hollow for containing wiring that connects the print cartridges and other devices such as the cameras and lasers in the uppermost part of the casing with the lower casing 42, which includes a power supply (not shown) for powering the device. Vents (not shown) may be included for evacuating air from the casing 4 to form a vacuum. Lights may be provided in the casing 4.

Handles 210 are provided on the lower casing 42. Preferably eight handles are provided in total.

Figure 1 1 shows delta arms 202 for moving the print head. The delta arms move the print head (not shown in Figure 10) across the build platform to print the patterns necessary for the construction of the 3D product. A stepper motor 203 may be provided for moving the delta arms 202. Preferably, three stepper motors are provided, one for each delta arm.

The build platform 21 preferably has three apertures 225, into which a supporting protrusion 223 extends. In the depicted embodiment, there are three supporting protrusions 223 in total, one for each aperture. Each supporting protrusion 223 is mounted on a screw 229. Rotation of the screw 229 about its axis causes the supporting protrusion 223 to move along the axis, thereby raising or lowering the build platform 2 1 along the z axis. Each of the lead screws 221 is connected to a central gear 231 (see Figure 12). Rotation of the central gear 231 causes the screws 229 to rotate together since the central gear 231 engages hub gears 230, each of which surrounds a screw 229.

The laser mount 201 can be raised or lowered along the z-axis by screws 221 which are connected to the laser mount 201. Rotation of the screws 221 causes the laser mount 201 to move. The screws 221 are each rotated by a motor. Each screw may have its own motor. Alternatively, one motor may be provided for rotation all of the screws 221. Figure 12 shows the arrangement of the screws 221 relative to the screws 229 which move the build platform 221 , in the lower casing 42. In operation, a first layer of the product is created on the build platform 21 1. The print head dispenses the substance onto the build platform 21 1. The plane of laser light is parallel to the build platform 21 1. Laser light in the laser plane is incident on the layer of the product being created. Meeting the laser beam causes the substance, which is preferably a polymer, to cure. The print head moves to dispense the substance at a second location on the build platform 211. The substance will again meet the laser plane. The print head continues to move to print the first layer.

Upon completion of the first layer, the second layer is created on top of the first layer. The build platform 211 and the lasers are moved relative to one another so that the laser plane is in position to harden the material forming the second layer. In a preferred embodiment, the lasers are stationary and it is the build platform 211 which is moved along the z-axis so that the laser plane 103 is in position to harden the material forming the second layer.

In any of the above embodiments, the product may be created in an atmospherically controlled chamber. The temperature and/or the humidity and/or the pressure of the chamber may be adjusted. The chamber may be evacuated to form a vacuum. This is particularly important when printing with high melting point metals, for example titanium. Having a vacuum prevents the ambient temperature and humidity from disrupting the cooling process of the print.

Figure 14 is a plan view of a further embodiment which includes a laser 402 having a laser beam 404 which is parallel to the plane of the build platform 405 in use, and laser modules 401 each including a laser and a laser spreading means for spreading the laser beam into a plane of laser light 403 which is parallel to the plane of the build platform 405 in use.

The laser 402 may melt plastic or metal. A coating 409 is provided opposite the laser 402 to block its laser beam 404 and prevent it having effects outside the device. The laser modules 401 and the laser 402 are mounted on a laser mount 414. The laser mount 414 is circular. The laser mount has teeth 412 on its periphery which engage and are driven by teeth 410 on gears 408. Gears 408 are mounted on rods so that the gears 408 are level with the laser mount 414 for rotating the laser mount.

The plane of laser light from the laser modules 401 cures a liquid polymer dispensed from a first print head (not shown), as described above in relation to figures 5 and 6.

The laser beam 404 from the laser 402 develops a substance dispensed from a second print head (not shown), as described above in relation to figures 1 to 4. The substance dispensed by the second print head may be plastic or metal. This embodiment enables multiple materials to be printed by one device. The first and the second print heads are not active at the same time.

In operation, the second print head dispenses powder (plastic or metal) onto the collimated laser beam 404. The laser beam 404 can be moved to align with the substance dispensed from the second print head by means of the gears 408 which rotate the laser mount 414 to alter the position of the laser beam 404. It may be necessary to temporarily deactivate the laser to avoid the laser beam 404 damaging parts which have already been printed. Note that the lasers of the laser modules 401 may be turned off when the laser 402 is active. The laser 402 may then be turned off and the laser modules 401 turned on to create the plane of laser light 403. The first print head may then dispense a liquid polymer, according to the programmed pattern. The polymer is cured by the plane of laser light.

To create a subsequent layer, the build platform moving means moves the build platform 405 so that the laser beams are co-incident with the subsequent layer to be created.

Optionally, a further laser or lasers mounted on a further laser mount (not shown) may be provided with the embodiment shown in figure 14. A laser mount moving means can move the further laser mount along the z-axis. Once the product has been built, the further laser or lasers can be moved along the z-axis so that their beams are incident on the outer layers of the product for smoothing the product.

Figure 15 is a further embodiment in plan view. A first laser 501 having a laser beam 503 is provided for melting a first substance, and a second laser 502 having a laser beam 504 is provided for melting a second substance. The first substance may be a metal having a first melting point and the second substance may be a metal having a second melting point. Alternatively, the first substance may be a plastic powder and the second substance may be a metal powder. A coating 409 is provided opposite each of the lasers 501, 502 to block their laser beams 503, 504 and prevent them having effects outside the device.

The first laser 501 and the second laser 502 are not active at the same time. Each laser is active when its associated print head is active. The laser that melts the material with the higher melting point must not touch the material with the lower melting point which has already been printed.

It is possible to have more than two lasers for printing with more than two materials (not shown).

Figure 16 is a side view of an alternative print head which may be used with any of the other embodiments described herein. The print head comprises a first nozzle 607, a second nozzle 614 and a third nozzle 615. A laser beam or laser plane 603 having a height h is parallel to the build platform 605. The first nozzle 607 deposits a droplet 621 of a substance, preferably a polymer, in a first layer. The second nozzle 614 deposits a droplet 619 of a substance, preferably a polymer, in a second layer on top of the droplets 621 deposited from the first nozzle 607. The third nozzle 615 deposits a droplet 617 of a substance, preferably a polymer, in a third layer on top of the droplet 619 deposited from the second nozzle 614.

The height h of the laser beam or laser plane 603 is equal to or greater than the height of the first, second and third layers so that the laser beam or laser plane 603 is incident on the first droplet 621 , the second droplet 619, and the third droplet 617. The first nozzle 607, the second nozzle 614 and the third nozzle 615 preferably all spray the same type of liquid polymer.

In any of the embodiments described herein, the device may be controlled by a computer for creating the 3D product according to a product specification.

Claims

1. A device for creating a three-dimensional product, comprising a planar build platform for supporting the product, a print head for dispensing a substance for creating the three-dimensional product, and a laser for providing a laser beam for irradiating the substance for creating the three- dimensional product, wherein in use the laser beam is parallel to the plane of the build platform.

2. The device according to claim 1 , wherein the substance is a polymer, preferably a liquid polymer.

3. The device according to claim 1 or 2, wherein the print head is a polymer dispensing print head for dispensing a polymer, preferably a liquid polymer.

4. The device according to claim 1 , 2, 3, wherein the print head sprays the substance in a spray direction, and the print head is arranged so that the spray direction is substantially perpendicular to the laser beam in use.

5. The device according to claim 4, further comprising a second print head for dispensing a second substance for creating the three-dimensional product.

6. The device according to claim 5, wherein the second print head sprays the second substance in a spray direction, the spray direction of the second print head being parallel to the spray direction of the first print head.

7. The device according to any one of the preceding claims, further comprising at least one colour print head for providing a colour substance, wherein the at least one colour print head is arranged to spray the colour substance to converge with the substance dispensed from the first print head.

8. The device according to any one of the preceding claims, further comprising a spreading means for spreading the laser beam into a plane, wherein the spreading means is arranged so that in use the laser beam is spread into a plane which is parallel to the build platform.

9. The device according to any one of the preceding claims, comprising a second laser for providing a second laser beam for irradiating the substance for creating the three-dimensional product, the second laser being arranged so that its laser beam is parallel to the plane of the build platform.

10. The device according to claim 9, comprising a second spreading means for spreading the second laser beam into a plane, wherein the second spreading means is arranged so that in use the second laser beam is spread into a plane which is parallel to the build platform.

1 1 . The device according to claim 9 or 10, comprising a third laser for providing a third laser beam for irradiating the substance for creating the three-dimensional product, the third laser being arranged so that its laser beam is parallel to the plane of the build platform.

12. The device according to claim 11 comprising a third spreading means for spreading the third laser beam into a plane, wherein the third spreading means is arranged so that in use the third laser beam is spread into a plane which is parallel to the build platform.

13. The device according to claim 11 or 12, wherein the first laser, the second laser and the third laser are spatially arranged to form the corners of an equilateral triangle.

14. The device according to any one of claims 8 to 13, wherein the or each spreading means is a lens.

15. The device according to claim 1 , wherein the or each lens is a powell lens.

16. The device according to any one of claims 1 to 9, further comprising a laser directing means for directing the laser beam to a plurality of different locations in a plane which is parallel to the build platform.

17. The device according to any one of the preceding claims, further comprising a print head moving means for moving the print head.

18. The device according to claim 17, wherein the print head moving means comprises a delta arm.

19. The device according to any one of the preceding claims, further comprising a build platform moving means for moving the build platform.

20. The device according to claim 19, wherein the build platform moving means is arranged to move the build platform in a direction which is perpendicular to the plane of the build platform for moving the build platform between a first layer creating position and a second layer creating position.

21 . The device according to claim 19 or 20, wherein the build platform moving means comprises at least one screw and a stepper motor.

22. The device according to any one of the preceding claims, further comprising a laser moving means for moving the or each laser between a first layer creating position in which the laser beam of the or each laser is parallel to the build platform, and a second layer creating position in which the laser beam of the or each laser is parallel to the build platform.

23. The device according to claim 22, wherein the laser moving means comprises at least one screw and a stepper motor.

24. The device according to any one of the preceding claims, further comprising at least one camera for imaging the product.

25. The device according to claim 24, comprising at least three cameras for imaging the product.

26. The device according to claim 25, comprising at least fifteen cameras for imaging the product.

27. The device according to any one of the preceding claims, wherein the print head comprises a first nozzle for dispensing a substance for creating a first layer of the three-dimensional product, and at least a second nozzle for dispensing a substance for creating a second layer of the three- dimensional product on top of the first layer.

28. The device according to claim 27, wherein the print head comprises a third nozzle for dispensing a substance for creating a third layer of the three-dimensional product on top of the second layer.

29. A method of creating a three-dimensional product, comprising creating a layer of the product by depositing a substance from a print head onto a laser beam, wherein the laser beam is parallel to the layer being created.

30. The method of claim 29, further comprising moving the print head along an axis to create a first line of the product.

31 . The method of claim 30, further comprising displacing the print head perpendicular to the axis.

32. The method of claim 31 , further comprising creating a second line of the product which is parallel to the first line.

33. The method of any one of claims 29 to 32, further moving the laser beam from a first position to a second position and moving the print head so that the product is deposited onto the laser beam at the second position.

34. The method of any one of claims 29 to 33, further comprising providing a laser spreading means for spreading the laser beam into a plane which is parallel to the layer being created.

35. The method of claim 34, further comprising providing a second laser and a second laser spreading means for spreading the second laser beam into a plane which is parallel to the layer being created, and a third laser and a third laser spreading means for spreading the third laser beam into a plane which is parallel to the layer being created.

36. The method of any one of claims 29 to 35, comprising using the device as defined in any one of claims to 26.

37. A method of creating a three-dimensional product substantially as herein described.

38. A device for creating a three-dimensional product substantially as herein described with reference to the accompanying drawings.