A method and a 3D printer for 3D printing onto a flexible substrate
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- TECH 21 LICENSING LTD
- Filing Date
- 2024-08-29
- Publication Date
- 2026-07-08
AI Technical Summary
Existing 3D printing techniques struggle to achieve strong bonding between printed features and flexible substrates, often resulting in damage to the nozzle or the substrate due to direct contact, and inefficient heat management which hampers material penetration.
The method involves using a compressible layer, preferably a foam, attached to a rigid support, which allows the print nozzle to press firmly against the flexible substrate without causing damage, enhancing material penetration and bonding by insulating the printing area and slowing down the solidification process.
This approach significantly improves the bonding between the printed features and the flexible substrate, allowing for deeper material penetration and better anchoring, while preventing damage to the nozzle and substrate, and enabling the creation of more complex features on flexible materials like gloves.
Smart Images
Figure GB2024052246_06032025_PF_FP_ABST
Abstract
Description
[0001] A METHOD AND A 3D PRINTER FOR 3D PRINTING ONTO A FLEXIBLE SUBSTRATE
[0002] The present invention relates to a method of 3D printing onto a flexible substrate and to a 3D printer suitable for that purpose.
[0003] Our earlier application WO 2022 / 223945 discloses a technique for 3D printing onto a glove in order to build up protective features onto the glove. The present invention relates to an enhancement of that technique.
[0004] US 2017 / 252980 and US 2019 / 047221 disclose 3D printers which have flexible attachments to the 3D printer bed. These are provided to facilitate separation of the 3D printed article from the bed and to avoid damage of the printer nozzle.
[0005] US 2021 / 0186154 discloses printing onto a foam.
[0006] According to the present invention, there is provided a method according to claim 1 .
[0007] The present invention uses a compressible layer into which the print nozzle is advanced in the printing process in order to press against a flexible substrate. Usually, any contact between the print nozzle and the object which is being printed is avoided, as this can damage the article and / or the nozzle. In this case however, any such damage is avoided by the presence of the compressible layer which compresses in order to accommodate the nozzle and to allow the nozzle to press firmly against the flexible substrate.
[0008] The fact that the nozzle is pressing against the flexible substrate, enhances the ability of the material being printed to penetrate the flexible substrate, thereby improving the bond between the printed features and the flexible substrate. This is contrasted from US 2017 / 252980 and US 2019 / 047221 in which the 3D printed material does not penetrate a flexible substrate as 3D printed article is specifically designed to be removed from the underlying layer. In US 2021 / 0186154, the foam is the printed article so there is no compressible layer on a rigid support.
[0009] Further, in the previous technique, the last in which the glove is supported is a metal which quickly conducts heat away from the material being printed. In the present invention, the compressible layer can insulate the area of the flexible substrate onto which the material is being printed. This slows down the solidification process of the printed material thereby further allowing it to penetrate into the flexible substrate. This provides further improvements in the bonding.
[0010] The flexible substrate can be any suitable article such as leather or foam. Preferably, the flexible substrate is a fabric. The substrate may be porous or have a rough surface to enhance the anchoring between the substrate and the printed material. In the case of the rough surface, the 3D printing material may only penetrate into the substrate to a limited extent.
[0011] The compressible layer may be any suitable compressible layer, such as a compressible polymer. However, it is preferably a foam as this has well-controlled properties and provides a reasonable level of support for the flexible substrate when it is not deformed, but can easily be deformed by the nozzle. It also provides a good level of insulation thereby enhancing the advantage as set out above.
[0012] The compressible layer is preferably attached to the rigid support. This allows the flexible layer with the 3D printing, to be more easily removed from the rigid support.
[0013] The compressible layer preferably forms the uppermost face on which the flexible layer is mounted. This allows the print nozzle to more readily penetrate the compressible layer.
[0014] The 3D printing can be controlled to ensure that the material printed form the 3D nozzle does not penetrate the compressible layer. This ensures that the flexible substrate does not get bonded to the compressible layer by the 3D printing material. To help to ensure that this is done more reliably, the compressible layer preferably is impervious to the 3D printing material, for example, it may be a closed cell foam.
[0015] Although the invention is motivated by improving on the technique of WO 2022 / 223945, in the field of a glove mounted on a last, it can be applied to any situation where 3D printing is required onto a flexible substrate. For example, the rigid support may be the top of a table or other surface below the 3D printer nozzle onto which the flexible substrate is clamped. Preferably, the rigid support is a last and the flexible substrate is stretched over the last.
[0016] In the broadest sense, only a single layer may be printed by the above method. However, in order to build up larger features, additional layers are preferably printed. The method preferably further comprises printing a first layer with the nozzle compressing the compressible layer and elevating the nozzle to be spaced from the flexible substrate before printing a further layer on top of the first layer. The first layer is printed using the above technique to ensure good bonding between the first layer and the article. Features are then built up on top of this first layer in a conventional way.
[0017] The present invention can be applied to any article where 3D printing onto a flexible substrate is required. However, preferably the flexible substrate is part of a glove.
[0018] The present invention also extends to a 3D printer according to claim 7. In this case, the compressible layer is preferably a foam and the rigid support is preferably a last.
[0019] The compressible layer is preferably attached to the rigid support. The compressible layer is a closed cell foam.
[0020] The nozzle is preferably movable to compress the compressible layer downwardly by at least 3%, more preferably at least 10% and most preferably 20% of its uncompressed thickness. This represents a deliberate attempt to move the nozzle to compress the compressible layer to achieve the above described effect.
[0021] Examples of the method and 3D printer in accordance with the present invention will now be described with reference to the accompanying drawings, in which:
[0022] Figure 1 is a cross section through a 3D printer with a printed article in place;
[0023] Figure 2 is a perspective view of a last;
[0024] Figure 3 is a plan view of the last; Figure 4 is a cross section through part of a last with a glove in place;
[0025] Figure 5 is a cross section showing the interaction between the print nozzle and the article / last;
[0026] Figure 6 is similar to Figure 4 showing an alternative version of the last.
[0027] The 3D printer depicted in Fig. 1 is taken from WO 2022 / 223945, which represents a type of printer suitable for use in the present invention.
[0028] As shown in Fig. 1 , a number of protective features 1 are printed onto a glove body 2 which is stretched over a last 3. The features 1 are preferably formed of a relatively soft polymer such as TPU.
[0029] The last 3 is placed on a reference plate 12 which has a hook like structure 20 in order to locate it with respect of the edge of the print bed 21 . Alternatively or additionally locator pins in the reference plate 12 may be provided that align with holes in the print bed 21 to assist with location. The 3D printer has a print head 30 which is supported on a gantry 31 for movement in a horizontal plane to eject the printed material from nozzle 32. The nozzle 32 is movable vertically.
[0030] Further details of the printer and the last are provided in WO 2022 / 223945.
[0031] The present invention concerns an adaptation of the last 3 and the printing technique. The last 3 is covered with a layer of foam 33 which extends across almost all of the upper surface of the last 3 on which printing is carried out. As shown in Fig 4, the foam layer 33 may terminate slightly short of the edge of the last 3 in order to reduce the chances of the edge of the foam layer 33 catching the glove body 2 when it is placed onto the last 3.
[0032] The presence of the foam layer 33 allows for a novel method. In particular, as shown in Fig 5 the nozzle 32 is advanced to a position in which it depresses the glove body 2 and compresses the foam layer 33. This is the position of the nozzle 32 in which the first layer of polymer is printed. Because the nozzle 32 is pressed very firmly against the glove body 2, as the polymer is injected from the nozzle 32, the polymer penetrates more deeply into the glove body 2. As the foam layer 33 provides a level of insulation above the last 3, the polymer will remain fluid for longer thereby also enhancing the penetration into the body 2.
[0033] Once the first layer is complete, the nozzle 32 is withdrawn to a more conventional position in which it is not in contact with the glove body 2, but is spaced very slightly from it to enable additional layers of polymer to be printed to the previously formed base layer in a conventional manner.
[0034] Fig 6 has a different configuration of the last 3 in which a groove 34 is formed around the edge of the last 3. The glove will often have an internal seam and this can be accommodated in the groove 34, thereby allowing a good flat surface to be achieved on the top surface of the last 3.
Claims
CLAIMS:1 . A method of 3D printing onto a flexible substrate, the method comprising mounting the flexible substrate onto a compressible layer on a rigid support in a 3D printer with a print nozzle; advancing the print nozzle towards the flexible substrate to contact and depress the flexible substrate and compress the compressible layer; and while in this position, traversing the print nozzle across the flexible substrate and printing from the 3D nozzle into the flexible substrate.
2. A method according to claim 1 , wherein the flexible substrate is a fabric.
3. A method according to claim 1 or claim 2, wherein the compressible layer is a foam.
4. A method according to any preceding claim, wherein the rigid support is a last and the flexible substrate is stretched over the last.
5. A method according to any preceding claim, wherein the method comprises printing a first layer with the nozzle compressing the compressible layer and elevating the nozzle to be spaced from the flexible substrate before printing a further layer on top of a first layer.
6. A method according to any preceding claim, wherein the flexible substrate is part of a glove.
7. A method according to any preceding claim, wherein the compressible layer is attached to the rigid support.
8. A method according to any preceding claim, wherein the compressible layer forms the uppermost face on which the flexible layer is mounted.
9. A method according to any preceding claim, wherein the compressible layer is impervious to the 3D printing material.
10. A method according to claim 9, wherein the compressible layer is a closed cell foam.
11. A method according to any preceding claim, further comprising moving the nozzle to compress the compressible layer vertically by at least 3%, preferably at least 10% and more preferably 20% of its uncompressed thickness.
12. A 3D printer comprising a print bed formed of a rigid support covered by a top layer which is a compressible layer, the printer further comprising a print nozzle, the nozzle being movable downwardly into the compressible layer to compress the compressible layer.
13. A 3D printer according to claim 12, wherein the compressible layer is a foam.
14. A 3D printer according to claim 12 or claim 13, wherein the rigid support is a last.
15. A 3D printer according to any of claims 12 to 14, wherein the compressible layer is attached to the rigid support.
16. A 3D printer according to any of claims 12 to 15, wherein the compressible layer is a closed cell foam.
17. A 3D printer according to any of claims 12 to 16, wherein the nozzle is movable to compress the compressible layer vertically by at least 3%, preferably at least 10% and more preferably 20% of its uncompressed thickness.