WO2023227455A1

WO2023227455A1 - A 3d printing device and a 3d printing method

Info

Publication number: WO2023227455A1
Application number: PCT/EP2023/063373
Authority: WO
Inventors: Matthias Wendt; Jacobus Petrus Johannes VAN OS; Peter Deixler
Original assignee: Signify Holding B.V.
Priority date: 2022-05-23
Filing date: 2023-05-17
Publication date: 2023-11-30

Abstract

A 3D printing device (1) comprising a nozzle unit (2), the nozzle unit (2) comprising a first inlet (3) configured to receive a first 3D printing material (11) comprising an embedded photochromic component (32), a second inlet (4) configured to receive a second 3D printing material (12) comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component (32), an outlet (5), and a first channel (6) leading from the first inlet (3) to the outlet (5) and configured to lead the first 3D printing material (11) from the first inlet (3) to the outlet (5), the 3D printing device (1) further comprising a first light source (8) configured to, in operation, emit first light of a first wavelength suitable for activating the photochromic component (32) of the first 3D printing material (11), the first light source (8) being arranged such as to, in operation, emit the first light towards and into the first channel (6) at a lighting position (9) located upstream of the outlet (5), and the nozzle unit (2) further comprising a second channel (7) leading from the second inlet (4) to a debouching position (10) located downstream of the lighting position (9) at or adjacent to the first channel (6), and configured to lead the second 3D printing material (12) from the second inlet (4) to the debouching position (10).

Description

A 3D PRINTING DEVICE AND A 3D PRINTING METHOD

FIELD OF THE INVENTION

The present invention relates generally to coloring and/or patterning of 3D printed products, and especially light shades and luminaires. More specifically, the present invention relates to a 3D printing device comprising a nozzle unit. The present invention further relates to a 3D printing method.

When used herein in connection with a layer or filament of printing material, the term “being deposited” is intended to refer to the layer or filament that is exiting the nozzle and to be deposited as a layer.

When used herein in connection with a layer or filament of printing material, the term “latest” is intended to refer to the last layer of printing filament having been completed at a particular given point of time in a printing process.

BACKGROUND OF THE INVENTION

In recent years, the market for 3D printed luminaires has been and still is growing. 3D printed luminaires have especially been demonstrated as a sustainable alternative to luminaires produced conventionally. 3D printed luminaires may be manufactured in a wide variety of forms and colors.

It is known to supply both a shell material and a core material to a heated nozzle system which covers the core with the shell material while depositing in the 3D printed structure. The core material and the shell material are different from one another. Both materials are supplied by individual digital controlled extrusion systems. For instance, the user may play with the amount of each material to obtain particular patterns. Even parts of the print can be made of only shell material or only core material.

Recently there has been much progress on the use of photochromic dyes in 3D printing materials. The purpose is to create re-programmable multi-color textures that are made from a single material only. Known is for instance photochromic inks that can switch their appearance from transparent to colored when exposed to light of a certain wavelength. By mixing cyan, magenta, and yellow (CMY) photochromic dyes into a single solution and leveraging the different absorption spectra of each dye, each color channel in the solution can be controlled separately.

For instance, there has been developed a new light-sensitive paint that makes it cheap, easy, and fast to update the color and pattern on just about anything. All you need is a special UV light box and a few minutes of time. The paint is applied to a product. The paint itself is usually clear. But when exposed to particular frequencies of light, it reveals hidden pigments. When blasted with ultraviolet light, the paint turns black. Within just 60 seconds, ultraviolet light can draw an intricate grayscale pattern onto the paint’s surface — anything from printed words to mountainous landscapes — in high-resolution fidelity. Then the design stays around, even after you remove it from the UV light. If you want to add color, that’s possible, too. Technically, the paint is available in CMY (cyan, magenta, and yellow) variants, which can be mixed together into one paint that can express all three colors at once. To activate the colors, RGB (red, green, blue) light is projected at the paint, which can transfer the color almost like the paint is being stamped with light. This, however, takes longer in a process that varies by the actual colors within the design, presently about 10 minutes or more.

These photochromatic dyes could change the way we look at color forever — not as a permanent finish for a luminaire product, but as a temporary identity programmed into it. It may also allow printing-stage color programming for 3D printers to increase the manufacturing efficacy of a diverse luminaire portfolio with many different colors.

US 2020/0047481 Al discloses a method for printing multicolored three- dimensional objects. The method includes selectively exposing a photosensitive thermoplastic feedstock to light within an extrusion nozzle, the feedstock comprising a thermoplastic base mixed with a photosensitive material, extruding the exposed feedstock into a deposit to print an object, and photo-chemically developing the deposit to provide color to the deposit. US 2020/0047481 Al further discloses an apparatus for three- dimensional printing with an extrusion nozzle including a light exposing component for selectively exposing the photosensitive thermoplastic feedstock to light within the extrusion nozzle.

However, giving 3D printed luminaires a very individual color-appearance touch is still very much limited. In current state of the art, the 3D printed luminaires all show a typically homogeneous color. It should be noted here that already the selection of color for the actual range generates the need for a huge amount of different colored 3D printing materials, typically in the form of filaments. This imposes very complex logistics in 3D printing hubs to enable handling of many different 3D printing materials.

In addition, there is a lack of color diversity within single luminaire parts stemming from the fact that it is not easy for 3D printers to generate units with patterns and color variations.

Most 3D printing technologies can only print in a single color. Hence, for creating multi-colored 3D printed luminaires, paint or other post-processing techniques are used to add color to the luminaire' s surface after the 3D printing has been completed. Alternatively, prior art also teaches methods to pattern 3D printing by providing prefabricated patterned printer filaments. The latter technique is however cumbersome, slow and inflexible. In addition, the resulting quality of the pattern alignment on the resulting 3D printed product is not very satisfactory due to production spread.

Finally, these coloring technologies generate issues when it comes to material recycling. When recycling 3D printed luminaires, it is very important to be able to mill the to-be-recycled materials within a homogenous color stream in order to allow cradle-to-cradle recycling with clear colors in final products.

Therefore, there is a desire to provide a 3D printing device and a 3D printing method which is fast and without need for changing material to obtain different colors and which in the luminaire factory allows fast design iteration between different target color orders without having to exchange the 3D printing material or cleaning the printing nozzles.

Further, there is a desire to provide such a 3D printing device and a 3D printing method which is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations.

Further, there is a desire to provide such a 3D printing device and a 3D printing method with which fixation of the color pattern with the aim of long life may be integrated with existing printing technology.

Finally, there is a desire to provide such a 3D printing device and a 3D printing method which allows to use just a single-color material for 3D printing, since this is advantageous for recycling or reprinting the luminaire with a new color as well as reducing or minimizing filament handling logistics in the 3D printing hub, while still enabling the diverse color appearances of the luminaires desired by the consumer. SUMMARY OF THE INVENTION

It is an object of the present invention to overcome this problem, and to provide a 3D printing device and a 3D printing method which is fast and without need for changing material to obtain different colors and which in the luminaire factory allows fast design iteration between different target color orders without having to exchange the 3D printing material or cleaning the printing nozzles.

It is a further object of the present invention to provide such a 3D printing device and a 3D printing method which is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations.

It is a further object of the present invention to provide such a 3D printing device and a 3D printing method with which fixation of the color pattern with the aim of long life may be integrated with existing printing technology.

It is a still further object of the present invention to provide such a 3D printing device and a 3D printing method which allows to use just a single-color material for 3D printing, such as to improve the possibilities for recycling or reprinting the luminaire with a new color as well as reducing or minimizing filament handling logistics in the 3D printing hub, while still enabling diverse and complex color appearances of the objects, particularly luminaires and lamp shades, to be 3D printed.

According to a first aspect of the invention, this and other objects are achieved by means of a 3D printing device comprising a nozzle unit, the nozzle unit comprising a first inlet configured to receive a first 3D printing material comprising an embedded photochromic component, a second inlet configured to receive a second 3D printing material comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component, an outlet and a first channel leading from the first inlet to the outlet and configured to lead the first 3D printing material from the first inlet to the outlet, the 3D printing device further comprising a first light source configured to, in operation, emit light of a first wavelength suitable for activating the photochromic component of the first 3D printing material, the first light source being arranged such as to, in operation, emit the first light towards and into the first channel at a lighting position located upstream of the outlet, and the nozzle unit further comprising a second channel leading from the second inlet to a debouching position, the debouching position being located downstream of the lighting position at or adjacent to the first channel, the second channel being configured to lead the second 3D printing material from the second inlet to the debouching position. By providing a nozzle unit construction which especially comprises two inlets and two channels as described above and by locating the first light source, and particularly the lighting position, as described above, a 3D printing device is provided which is fast and which considerably reduces or even eliminates any need for changing material to one of a different color. Such a 3D printing device further, in the luminaire factory, allows for obtaining different target color orders without having to exchange the 3D printing material or cleaning the printing nozzles during the process of printing a particular object.

With such a 3D printing device, the color of the first 3D printing material may be chosen since the color of the photochromic component may be adjusted by exposure to radiation, such as ultraviolet radiation, visible radiation or infrared radiation, from the first light source, thus allowing the formation of a color pattern in the printed object.

By providing especially that the debouching position of the second channel is located downstream to the lighting position, and thus downstream to the position at which the photochromic component of the first 3D printing material is activated, such a 3D printing device further enables fixation of the color pattern provided to the first 3D printing material by addition of the second 3D printing material. This in turn provides for obtaining a 3D printed product with a long life.

As the above advantages is obtained essentially by providing a novel nozzle unit as described above, such a nozzle unit may easily be integrated with existing 3D printing technology.

A further advantage of such a 3D printing device is that it allows to use just a single-color 3D printing material. This in turn improves the possibilities for recycling or reprinting a 3D printed object with a new color, and further reduces or minimizes filament handling logistics in the 3D printing hub, while still enabling the diverse color appearances of the objects desired by the consumer.

In an embodiment, the distance between the lighting position and the debouching position is at least 5 mm.

Thereby, the first 3D printing material may be allowed to cool after being provided with a desired color at the lighting position and before the second 3D printing material is added at the debouching position. This provides for a more color stable and durable end product.

In an embodiment, the second channel, at the debouching position, debouches into the first channel. Alternatively, or additionally, the second channel, at the debouching position, debouches into the first channel immediately adjacent to the outlet. Thereby a more compact nozzle unit and thus also 3D printing device is provided for. Also, when the second channel, at the debouching position, debouches into the first channel, this further allows for the final filament comprising both the first and the second 3D printing material to be provided with a particularly well defined shape and size which may be defined by the part of the first channel extending between the debouching position and the outlet.

In an embodiment, the 3D printing device is further configured to arrange the second 3D printing material around the first 3D printing material, such that the second 3D printing material forms a shell enclosing the first 3D printing material.

As the second 3D printing material comprises a light blocking component configured to block light of a wavelength suitable for activating the photochromic component of the first 3D printing material, enclosing the first 3D printing material in a shell of the second 3D printing material allows for a particularly efficient and optimal fixation of the color of the first 3D printing material as obtained at the lighting position.

In an embodiment, the 3D printing device is further configured to arrange the second 3D printing material around the first 3D printing material by any one or more of extrusion, depositing and spraying.

Thereby, the first 3D printing material may be provided with or enclosed by the second 3D printing material in a particularly simple, efficient and straight forward manner.

In an embodiment, the 3D printing device further comprises a second light source, the second light source being configured to, in operation, emit light of a second wavelength suitable for activating the photochromic component of the first 3D printing material, the second light source being arranged such as to, in operation, emit the second light towards and into the first channel at the lighting position.

Thereby more complex color patterning of the first 3D printing material may be obtained in a simple manner.

In an embodiment, the second light source is arranged opposite to or diametrically opposite to the first light source.

Thereby different, and in particular opposite, sides of the first 3D printing material may be provided with different colors in a simple manner.

In an embodiment, the 3D printing device further comprises a first light guide configured and arranged to lead the first light emitted by the first light source to the lighting position. In an embodiment, the 3D printing device further comprises a second light guide configured and arranged to lead the second light emitted by the second light source to the lighting position.

By providing a light guide leading light from the respective light source to the lighting position in the first channel, light losses between the light source and the lighting position may be reduced or avoided. Furthermore, the activation of the photochromic component and thus the color changes may be inflicted with an improved precision and an improved uniformness.

In an embodiment, the first light guide is integrated in the nozzle unit.

In an embodiment, the second light guide is integrated in the nozzle unit.

By integrating the respective light guide in the nozzle unit, a more compact nozzle unit and thus also 3D printing device is provided for. Furthermore, the respective light guide may in this way be protected against external influences which increases the durability of the respective light guide.

In an embodiment, the 3D printing device further comprises a projection device arranged and configured for imposing a pattern on any one or more of the first light emitted by the first light source and the second light emitted by the second light source.

Thereby, very complex color patterns may be inflicted on the first 3D printing material in a very simple manner. Thereby, a 3D printing device which is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations is provided for. Furthermore, such a 3D printing device is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations.

In an embodiment, any one or more of the first light source and the second light source is configured to, in operation, emit patterned light.

Thereby, the same advantages as mentioned above for a projection device may be obtained, while also providing for a 3D printing device with a particularly simple construction.

In an embodiment, the 3D printing device further comprises a modulation device, the modulation device being configured for one or more of modulating and dynamically modulating one or more of the light intensity, the wavelength spectrum and the frequency spectrum of one or more of the first light emitted by the first light source and the second light emitted by the second light source. Thereby, very complex color patterns may be inflicted dynamically on the first 3D printing material in a very simple manner. Thereby, a 3D printing device which is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations is provided for. Furthermore, such a 3D printing device is flexible for a wide variety of personalized colorful designs including complex color patterns or soft color variations.

The invention further relates to a 3D printing method comprising the steps of: a) feeding a first 3D printing material comprising an embedded photochromic component into a first inlet of a nozzle unit of a 3D printing device and through a first channel of the nozzle unit, the first channel leading from the first inlet to an outlet of the nozzle unit, b) feeding a second 3D printing material comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component into a second inlet of the nozzle unit and through a second channel of the nozzle unit, the second channel leading from the second inlet to a debouching position, c) causing the first light source to emit first light of a first wavelength suitable for activating the photochromic component of the first 3D printing material towards and into the first channel at a lighting position located upstream of the outlet such as to activate the photochromic component of the first 3D printing material, and d) at a debouching position of the second channel, the debouching position being located downstream of the lighting position at or adjacent to the first channel, arranging the second 3D printing material around the first 3D printing material such that the second 3D printing material forms a shell enclosing the first 3D printing material, where step d) is performed subsequently to step c).

In an embodiment, the 3D printing method further comprises arranging the second 3D printing material around the first 3D printing material by any one or more of extrusion, depositing and spraying.

In an embodiment, the 3D printing method further comprises causing a second light source to emit second light of a second wavelength suitable for activating the photochromic component of the first 3D printing material towards and into the first channel at the lighting position such as to activate the photochromic component of the first 3D printing material. In an embodiment, the 3D printing method further comprises imposing a pattern on any one or more of the first light emitted by the first light source and the second light emitted by the second light source, and

In an embodiment, the 3D printing method further comprises one or more of modulating and dynamically modulating one or more of the light intensity, the wavelength spectrum and the frequency spectrum of one or more of the first light emitted by the first light source and the second light emitted by the second light source.

The invention still further relates to a 3D printing material, such as a 3D printing material for use as a first 3D printing material in a 3D printing method according to the present invention, or in a 3D printing device according to the present invention, the 3D printing material comprising a base material and a photochromic component, where the 3D printing material further comprises at least one transparent bead, where the photochromic component is embedded in the at least one transparent bead, and where the at least one transparent bead is embedded in the base material.

By embedding the photochromic component in the at least one transparent bead, the photochromic component is protected or shielded against the heat to which the first 3D printing material is subjected on the way through an extrusion nozzle unit of a 3D printing device.

In an embodiment, the 3D printing material is provided as a filament or as a filament-shaped material.

In an embodiment, the at least transparent bead is made of a heat resistant transparent material.

In an embodiment, the at least transparent bead is made of glass or is a glass bead.

It is noted that the invention relates to all possible combinations of features recited in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

Fig. 1 shows a cross-sectional view of a 3D printing device according to an embodiment of the invention in the process of printing a 3D printed object in the form of a lamp shade. Fig. 2 shows a cross-sectional view of an exemplary lamp with a lamp shade 3D printed using a 3D printing device according to the invention.

Fig. 3 shows a close up of a detail of the lamp shade shown in Fig. 2 corresponding to the insert III on Fig. 2.

Fig. 4 shows a cross sectional view of a 3D printed filament formed using a 3D printing device according to the invention.

Fig. 5 shows a cross-sectional view of a detail of another exemplary lamp with a lamp shade 3D printed using a 3D printing device according to the invention.

Fig. 6 shows a schematical and partially exploded illustration of the components of a first 3D printing material and a second 3D printing material according to an embodiment of the invention.

Fig. 7 shows a cross-sectional view of a 3D printing device according to another embodiment of the invention in the process of printing a 3D printed object in the form of a lamp shade.

Fig. 8 shows a close up of a detail of the 3D printing device according to Fig.

7 corresponding to the insert VIII on Fig. 7.

Fig. 9 shows a flow diagram illustrating a 3D printing method according to the invention.

As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention. Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

Fig. 1 shows a cross-sectional view of a 3D printing device 1 according to an embodiment of the invention in the process of printing a 3D printed object 27.

The 3D printing device 1 comprises a 3D printer extruder unit 20 comprising a nozzle unit 2. The nozzle unit 2 is an extrusion nozzle configured to heat and extrude 3D printing material 11, 12 to form filaments or printing layers 21, 22, 23 with the aim of printing an object 27 with a predetermined outline 24. In the context of the present invention, the object 27 to be printed is typically an optical component, a luminaire component or a lamp component. As shown on Fig. 1, the object 27 is a lamp shade.

During a printing process, the 3D printer extruder unit 20 is moved in a printing direction 26 while depositing printing layers 21, 22 and 23. Alternatively, or additionally, the printed object or outline 24 may be moved in the printing direction 26. For instance, for rotational 3D printing it is possible to provide a linearly (and radially) moving 3D printer extruder unit and a rotating and axially retracting printed object or outline 24. The 3D printing device 1 is programmed to follow the predetermined outline 24 of the object 27 to be printed. In the embodiment shown, the object 27 to be printed is an object being rotationally symmetric around a symmetry axis 25. Therefore, the printing direction 26 is a direction of rotation around the symmetry axis 25. The object 27 to be printed thus comprises a stack of layers 21, 22, 23. During the printing process the stack of layers comprise a number of previously deposited layers 21, 22 and a freshly deposited layer 23, the freshly deposited layer 23 being deposited on top of the uppermost previously layer 22. Reference numeral 40 denotes the printing material 40 shortly after leaving the outlet 5, that is the printing material 40 that has just exited the outlet 5 and that is forming the freshly deposited layer 23.

Generally, and irrespective of the embodiment, the nozzle unit 2 comprises a first inlet 3 configured to receive a first 3D printing material 11, a second inlet 4 configured to receive a second 3D printing material 12, an outlet 5, a first channel 6 leading from the first inlet 3 to the outlet 5, and a second channel 7.

The first 3D printing material 11 generally comprises a photochromic component 32. The first 3D printing material 11 further comprises a base material 31. The photochromic component 32 is embedded or dispersed in the base material 31. The photochromic component 32 may be activated to obtain a desired color by exposure to light of a predetermined wavelength, particularly a wavelength within one or more of the ultraviolet (UV) range, the visible range and the infrared (IR) range. Different first 3D printing materials 11 are shown in Figs. 4-6 and will be described in more detail further below.

The second 3D printing material 12 comprises a material 33 comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component. The light blocking component is chosen such as to block wavelengths of light suitable for activating or deactivating the photochromic component 32 of the first 3D printing material 11. As it has recently become possible to perform FDM printing with glass, the light blocking material 33 may in one particular embodiment be glass. In such an embodiment the photochromic component 32 should be able to withstand high temperatures for a short period of time. That means that if the first material 31 comprises beads 34 with the photochromic component 32 embedded therein (cf. Fig. 6), the beads 34 should have a thermal barrier around them, so that the maximum temperature within the beads 34 is limited.

The nozzle unit 2 further comprises a first light source 8. The first light source 8 is configured to, in operation, emit first light. The first light comprises a first wavelength being suitable for activating the photochromic component 32 of the first 3D printing material 11. The first light source 8 is arranged such as to, in operation, emit the first light towards and into the first channel 6 at a lighting position 9. The lighting position 9 is located upstream of the outlet 5. The second channel 7 leads from the second inlet 4. The first light source 8 may be configured to, in operation, emit patterned light. The first light source 8 may for example be a laser light source or an LED light source or a Xenon lamp, optionally provided with collimating optics in front thereof. The light source 8 may be programmable such as to enable providing both the light flux and the wavelength or frequency spectrum required for defining the desired photochromic color change of the to-be-printed filament. The first light source 8 is configured to emit light, e.g. in the UV spectral range.

The second channel 7 leads from the second inlet 4 to a debouching position 10. The second channel 7 is debouching at the debouching position 10. The debouching position 10 is located downstream of the lighting position 9. In the embodiment shown in Fig. 1, the debouching position 10 is further located upstream of the outlet 5. The second channel 7 further debouches into the first channel 6. In other embodiments, the debouching position 10 may be located adjacent to the first channel 6, at the outlet 5 or even immediately adjacent to and downstream of the outlet 5.

The first 3D printing material 11 is contained in a suitable container or storage, such as a first reel 13. From the first reel 13, the first 3D printing material 11 is fed into the first inlet 3. At least one positioning wheel 16, 17 may be provided adjacent to and downstream of the first inlet 3 to ensure proper positioning and proper speed of propagation of the first 3D printing material 11 in the first channel 6. The first 3D printing material 11 is then led through the first channel 6, and past the lighting position 9. At the lighting position 9, the photochromic component 32 is activated to provide the first 3D printing material with a desired color. Eventually, the first 3D printing material 11 leaves the first channel 6 through the outlet 5. The photochromic component 32 is thus exposed to the first light synchronously to the heating or melting inside the nozzle unit 2. The printing color of the object 27 to be printed is thus defined before the first 3D printing material 11 leaves the nozzle unit 2. The light exposition activating the photochromic component 32 should be synchronized with the 3D printing process to allow for proper color programming the printing pattern of the object 27 to be printed.

The 3D printing device 1 is configured to arrange the second 3D printing material 12 around the first 3D printing material 11, such that the second 3D printing material 12 forms a shell enclosing the first 3D printing material 11. This may for instance be obtained by the second 3D printing material 12 being arranged on the first 3D printing material 11 by any one or more of extrusion, depositing and spraying.

The debouching position 10 is arranged in a distance D from the lighting position 9. The distance D is chosen such that the first 3D printing material 11 is allowed to, after activation of the photochromic component 32, cool sufficiently to allow the second 3D printing material 12 to be arranged forming a shell or cladding enclosing the first 3D printing material 11. For instance, the distance D between the lighting position 9 and the debouching position 10 is at least 5 mm.

The second 3D printing material 12 is contained in a suitable container or storage, such as a second reel 14. From the second reel 14, the second 3D printing material 12 is fed into the second inlet 4 and through the second channel 7. At least one positioning wheel 18, 19 may be provided adjacent to and downstream of the second inlet 4 to ensure proper positioning and proper speed of propagation of the second 3D printing material 12 in the second channel 7. The second 3D printing material 12 is then led through the second channel 7 and leaves the second channel 7 at the debouching position 10. At the debouching position 10, the second 3D printing material 12 is arranged around the first 3D printing material 11, such that the first 3D printing material 11 forms a core of the filament or layer 23 being deposited, and the second 3D printing material 12 enclosing the core to form a cladding of the filament or layer 23 being deposited.

The 3D printing device may further comprise a first light guide 15 configured and arranged to lead the first light emitted by the first light source 8 to the lighting position 9. The first light guide 15 thus extends from the first light source 8 to a vicinity of the lighting position 9.

The 3D printing device 1 may optionally also comprise a projection device 38 (Fig. 8). The projection device 38 is arranged and configured for imposing a pattern on the first light emitted by the first light source 8. The projection device 38 may be configured to employ DLPs or LCDS for pattern generation. The patterned light thus formed may be controllable in spectral contents in order to make best use of the photochromic behavior of the photochromic component 32. Optics like a conical mirror may be used to project a flat image pattern from the center of the light shade to the complete inner layers of the first 3D printing material 11. This may allow for a very rapid erase and/or patterning process.

The 3D printing device 1 may optionally also comprise a modulation device 39 (Fig. 8). As shown in Fig. 8, the modulation device 39 is arranged and configured to modulate the second light emitted by the second light source 8. The modulation device 39 may be configured to impose the modulation dynamically. The modulation device 39 may be configured to modulate one or more of the light intensity, the wavelength spectrum and the frequency spectrum of the second light emitted by the second light source 8. The modulation device 39 may be configured to enable dynamic modulation by controlling the drive current of the second light source 8 or any programmable shading mechanisms keeping the light away from all parts of the first 3D printing material 11 or already deposited filament or layer 23. A similar modulation device may also be arranged and configured to modulate the first light emitted by the first light source 8.

Referring now first to Fig. 2, a luminaire 28 comprising an object 27 being 3D printed as described above is shown in cross-section. The luminaire 28 comprises a lamp holder 29 and a light shade 270. The light shade 270 is the object 27 being 3D printed. Inside the light shade 270 a light source in the form of a bulb 30 is mounted. As is shown in more detail in Fig. 3, the 3D printing process used to form the light shade 270 ensures that the inner and outer surface of the light shade 270 is covered with a light blocking filter layer 120 consisting of the second 3D printing material 12. The core 110 of the light shade 270 is formed of the first 3D printing material 11 having been provided with a desired color as described above. The exposition to the color-defining light flux happens before the final layers are deposited in the 3D printing factory as also described above. Light of wavelengths suitable for activating or deactivating the photochromic component are thereby blocked from reaching the core 110 thanks to the light blocking filter layer 120.

Referring to Fig. 4, a cross sectional view of a single printing filament or layer 23 is shown. Generally, the printing layer 23 comprises a core 310 made of the first 3D printing material 11 and a cladding 33 made of the second 3D printing material 12.

As mentioned above, the first 3D printing material 11 generally comprises a photochromic component 32 and a base material 31. As shown in Fig. 4, the photochromic component 32 is photochromic particles 320. Suitable photochromic components 32 also include photochromic dyes. In the example shown in Fig. 4, the full volume of the core is filled with the photochromic component 32. In other embodiments, only a part of the core may be filled with the photochromic component 32.

Fig. 5 shows an illustration of a detail of a 3D printed object 27, the detail being similar to that shown in Fig. 3. The core 310 of the object is formed of the first 3D printing material 11 having been provided with a desired color as described above, for each printing layer corresponding to the core 310 shown in Fig. 4. The outer layers 330 are made of the second 3D printing material 12, for each printing layer corresponding to the cladding 33 shown in Fig. 4.

Another suitable first 3D printing material 11 is illustrated in Fig. 6. This first 3D printing material 11 also comprises a base material 31 and a photochromic component 32, and further comprises at least one transparent bead 34. The at least one transparent bead 34 may for instance be a glass bead. The at least one transparent bead 34 may also be made of another suitable heat resistant and transparent material, such as a suitable silicone. In this case, the photochromic component 32 is embedded in the at least one transparent bead 34, and the at least one transparent bead 34 is in turn is embedded in the base material 31. Also shown in Fig. 6 is the second 3D printing material 12 forming a cladding 33 enclosing the first 3D printing material.

Fig. 7 shows a cross-sectional view of a 3D printing device 100 according to another embodiment of the invention in the process of printing a 3D printed object 27 in the form of a lamp shade. Fig. 8 shows an enlarged detail of the 3D printing device 100 of Fig. 7. The 3D printing device 100 differs from the 3D printing device 1 described above with reference to Fig. 1 in virtue of the following features.

The 3D printing device 100 comprises, in addition to the first light source 8, a second light source 35. The second light source 35 is very similar to the first light source 8 described above. However, the second light source 35 differs from the first light source 8 in that it is configured to, in operation, emit second light of a second wavelength suitable for activating the photochromic component 32 of the first 3D printing material 11. The second light source 35 is configured to emit light, such as for instance UV light. The second light source 35 may for example be a laser light source or an LED light source or a Xenon lamp, optionally provided with collimating optics in front thereof. The second source 35 may be programmable such as to enable providing both the light flux and the wavelength or frequency spectrum required for defining the desired photochromic color change of the to-be- printed filament. The second wavelength is different from the first wavelength of the first light provided by the first light source 8. The second light source 35 is arranged such as to, in operation, emit the second light towards and into the first channel 6 at the lighting position 9. The second light source 35 may optionally be arranged opposite to or diametrically opposite to the first light source 8. The second light source 35 may further be configured to, in operation, emit patterned light.

The 3D printing device 100 may further comprise a second light guide 36. The second light guide 36 is configured and arranged to lead the second light emitted by the second light source 35 to the lighting position 9. The second light guide 36 thus extends from the second light source 35 to a vicinity of the lighting position 9.

The 3D printing device 100 still further comprises a projection device 38 (Fig. 8). The projection device 38 is arranged and configured for imposing a pattern on the first light emitted by the first light source 8. Alternatively, or additionally, a similar projection device (not shown) may be arranged and configured for imposing a pattern on the second light emitted by the second light source 35. The projection device 38 may be configured to employ DLPs or LCDS for pattern generation. The patterned light thus formed may be controllable in spectral contents in order to make best use of the photochromic behavior of the photochromic component 32. Optics like a conical mirror may be used to project a flat image pattern from the center of the light shade to the complete inner layers of the first 3D printing material 11. This may allow for a very rapid erase and/or patterning process.

The 3D printing device 100 still further comprises an optional third light source 37. The third light source 37 is very similar to the first light source 8 and the second light source 35 described above. However, the third light source 37 differs in that it is configured to, in operation, emit third light of a third wavelength suitable for activating the photochromic component 32 of the first 3D printing material 11. The third light source 37 is typically configured to emit UV light. The third light source 37 may for example be a laser light source or an LED light source or a Xenon lamp, optionally provided with collimating optics in front thereof. The third light source 37 may be programmable such as to enable providing both the light flux and the wavelength or frequency spectrum required for defining the desired photochromic color change of the to-be-printed filament. The third wavelength is different from the second wavelength and the first wavelength. The third light source 37 is arranged such as to, in operation, emit the second light towards and onto the printing material 40 having just left the nozzle outlet 5. The third light source 37 may further be configured to, in operation, emit patterned light. The 3D printing device 100 also comprises a modulation device 39 (Fig. 8).

The modulation device 39 is arranged and configured modulating the second light emitted by the second light source 35. Alternatively, or additionally, a similar modulation device (not shown, but may be provided in lieu of and in the same position as the projection device 38 shown on Fig. 8) may be arranged and configured modulating the first light emitted by the first light source 8. The modulation device 39 may be configured to impose the modulation dynamically. The modulation device 39 may be configured to modulate one or more of the light intensity, the wavelength spectrum and the frequency spectrum of the second light emitted by the second light source 35. The modulation device 39 may be configured to enable dynamic modulation by controlling the drive current of the second light source 35 or any programmable shading mechanisms keeping the light away from all parts of the first 3D printing material 11 or already deposited filament or layer 23.

Finally, Fig. 9 shows a block diagram illustrating steps of a 3D printing method according to the invention. The 3D printing method employs a 3D printing device 1 or 100 according to any embodiment of the invention. Generally, and irrespective of the embodiment, the 3D printing method comprises the following steps.

In a step 50, a first 3D printing material 11 comprising an embedded photochromic component 32 is fed into a first inlet 3 of a nozzle unit 2 of a 3D printing device 1, 100 and through a first channel 6 of the nozzle unit 2, the first channel 6 leading from the first inlet 3 to an outlet 5 of the nozzle unit 2.

In a step 51, a second 3D printing material 12 comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component 32 is fed into a second inlet 4 of the nozzle unit 2 and through a second channel 7 of the nozzle unit 2. The second channel 7 leads from the second inlet 4 to a debouching position 10.

In a step 52, the first light source 8 is caused to emit first light of a first wavelength suitable for activating the photochromic component 32 of the first 3D printing material 11 towards and into the first channel 6 at a lighting position 9 located upstream of the outlet 5. Thereby, the photochromic component 32 of the first 3D printing material is activated when passing the lighting position 9.

In a step 53, which is performed subsequently to step 52, and which takes place at the debouching position 10 of the second channel 7, the second 3D printing material 12 is arranged around the first 3D printing material 11 such that the second 3D printing material 12 forms a shell enclosing the first 3D printing material 11. The debouching position 10 is located downstream of the lighting position 9 at or adjacent to the first channel 6.

Step 53 may be performed by any one or more of extrusion, depositing and spraying of the second 3D printing material 12 onto or around the first 3D printing material 11.

In a step following step 53 the thus formed filament 23 is deposited on a substrate or on a previously deposited printing layer 22 such as to form an object 27 to be 3D printed layer by layer. De deposition may follow a predefined outline 24 of the object 27 to be 3D printed.

Step 52 may further comprise causing a second light source 35 to emit second light of a second wavelength suitable for activating the photochromic component 32 of the first 3D printing material 11 towards and into the first channel 6 at the lighting position 9 such as to activate the photochromic component 32 of the first 3D printing material 11.

Step 52 may further comprise imposing a pattern on any one or more of the first light emitted by the first light source 8 and the second light emitted by the second light source 35 before causing the first light and/or the second light to activate the photochromic component 32 of the first 3D printing material 11.

Step 52 may further comprise one or more of modulating and dynamically modulating one or more of the light intensity, the wavelength spectrum and the frequency spectrum of one or more of the first light emitted by the first light source 8 and the second light emitted by the second light source 35 before causing the first light and/or the second light to activate the photochromic component 32 of the first 3D printing material 11.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

For example, the first light source 8 and/or the second light source 35 may be positioned such as to expose the first 3D printing material 11 to light activating the photochromic component 32 shortly after the 3D printing filament has left the nozzle outlet 5.

Alternatively, the activation of the photochromic component 32 to change the color of the first 3D printing material may also happen before the first 3D printing material reaches the extruder nozzle 2, and thus even before the heating process. In this case, however, the extrusion speed has to be known and kept relatively stable as any variation may produce inaccuracies of the deposited color pattern. It would also be feasible to apply one type of light modulation on a part of the first 3D printing material corresponding, in the finished state of the object 27 to be printed, to an outwards-facing part of the object 27, (e.g. to activate the photochromic component 32 to a red color) and to apply another, different, type of light modulation on a part of the first 3D printing material corresponding, in the finished state of the object 27 to be printed, to an inwards-facing part of the object 27 (e.g. to activate the photochromic component 32 to green). Consequently, despite of using just a single-material 3D printing material, the outside and inside of the lamp shade can be colored in different colors, such as red and green, respectively. This may for instance be obtained with a 3D printing device of the type shown in Fig. 7 and described above, where the first light source 8 and the second light source 35 are arranged opposite, and particularly diametrically opposite, to one another.

It is also feasible to expose the object 27 as printed with the first 3D printed material 11 to a triggering light flux after printing it, that is as a finished whole, and to fixate the color thus obtained by means of subsequently covering the whole object 27 with a light blocking filter layer configured to block light of a wavelength suitable for activating the photochromic component 32, for instance of the second 3D printing material 12. That may for instance be done by means of a spray coating.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

CLAIMS:

1. A 3D printing device (1) comprising a nozzle unit (2), the nozzle unit comprising: a first inlet (3) configured to receive a first 3D printing material (11) comprising an embedded photochromic component (32), a second inlet (4) configured to receive a second 3D printing material (12) comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component (32), an outlet (5), and a first channel (6) leading from the first inlet to the outlet and configured to lead the first 3D printing material from the first inlet to the outlet, the 3D printing device further comprising a first light source (8) configured to, in operation, emit first light of a first wavelength suitable for activating the photochromic component of the first 3D printing material, the first light source (8) being arranged such as to, in operation, emit the first light towards and into the first channel (6) at a lighting position (9) located upstream of the outlet, the nozzle unit further comprising a second channel (7) leading from the second inlet to a debouching position (10), the debouching position being located downstream of the lighting position (9), at or adjacent to the first channel (6), the second channel (7) being configured to lead the second 3D printing material from the second inlet to the debouching position, and the 3D printing device further being configured to arrange the second 3D printing material (12) around the first 3D printing material (11), such that the second 3D printing material forms a shell enclosing the first 3D printing material.

2. A 3D printing device according to any one of the above claims, wherein the second channel (7), at the debouching position, debouches one or more of into the first channel (6) and adjacent to the outlet (5).

3. A 3D printing device according to any one of the preceding claims, and further being configured to arrange the second 3D printing material (12) around the first 3D printing material (11) by any one or more of extrusion, depositing and spraying.

4. A 3D printing device according to any one of the above claims, and further comprising a projection device (38) arranged and configured for imposing a pattern on the first light emitted by the first light source.

5. A 3D printing device according to any one of the above claims, wherein the first light source (8) is configured to, in operation, emit patterned light.

6. A 3D printing device according to any one of the above claims, and further comprising a modulation device (39), the modulation device being configured for one or more of modulating and dynamically modulating one or more of the light intensity, the wavelength spectrum and the frequency spectrum of the first light emitted by the first light source.

7. A 3D printing device according to any one of the above claims, and comprising a second light source (35), the second light source being configured to, in operation, emit light of a second wavelength suitable for activating the photochromic component of the first 3D printing material, the second light source (35) being arranged such as to, in operation, emit the second light towards and into the first channel (6) at the lighting position (9).

8. A 3D printing device according to claim 7, and further comprising one or more of: a first light guide (15) configured and arranged to lead the first light emitted by the first light source to the lighting position, and a second light guide (36) configured and arranged to lead the second light emitted by the second light source to the lighting position.

9. A 3D printing method comprising: a) feeding (50) a first 3D printing material (11) comprising an embedded photochromic component (32) into a first inlet (3) of a nozzle unit (2) of a 3D printing device (1) and through a first channel (6) of the nozzle unit, the first channel leading from the first inlet to an outlet (5) of the nozzle unit, b) feeding (51) a second 3D printing material (12) comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component (32) into a second inlet (4) of the nozzle unit and through a second channel (7) of the nozzle unit, the second channel (7) leading from a second inlet (4) to a debouching position (10), c) causing (52) a first light source (8) to emit first light of a first wavelength suitable for activating the photochromic component of the first 3D printing material towards and into the first channel (6) at a lighting position (9) located upstream of the outlet such as to activate the photochromic component of the first 3D printing material, and d) at the debouching position (10) of the second channel (7), the debouching position (10) being located downstream of the lighting position (9) at or adjacent to the first channel (6), arranging (53) the second 3D printing material around the first 3D printing material such that the second 3D printing material forms a shell enclosing the first 3D printing material, wherein step d) is performed subsequently to step c).

10. A 3D printing method according to claim 9, and further comprising any one or more of arranging the second 3D printing material (12) around the first 3D printing material (11) by any one or more of extrusion, depositing and spraying, causing a second light source (35) to emit second light of a second wavelength suitable for activating the photochromic component of the first 3D printing material towards and into the first channel (6) at the lighting position (9) such as to activate the photochromic component of the first 3D printing material, imposing a pattern on any one or more of the first light emitted by the first light source (8) and the second light emitted by the second light source (35), and one or more of modulating and dynamically modulating one or more of the light intensity, the wavelength spectrum and the frequency spectrum of one or more of the first light emitted by the first light source (8) and the second light emitted by the second light source (35).

11. A 3D printing material for use as a first 3D printing material (11) in a method according to any one of claims 10-11, the 3D printing material comprising a base material (31) and a photochromic component (32), wherein the 3D printing material further comprises at least one transparent bead (34), wherein the photochromic component (32) is embedded in the at least one transparent bead (34), and wherein the at least one transparent bead (34) is embedded in the base material (31).

12. A 3D printing material according to claim 11, wherein the at least one transparent bead (34) is made of glass or of a heat resistant transparent silicone.

13. A 3D printed object comprising a first 3D printing material (11) comprising an embedded photochromic component (32), the first 3D printing material forming a core (310) of the object, and a second 3D printing material (12) comprising a light blocking component configured to block light of a wavelength suitable for activating the photochromic component (32), second 3D printing material (12) forming a cladding (33) enclosing the first 3D printing material, wherein the first 3D printing material (11) is a 3D printing material according to any one of claims 11 and 12.