Method for 3D printing on flexible substrate and 3D printer

Abstract

A method of 3D printing onto a flexible substrate (2) by mounting the substrate onto a compressible layer (33) on a rigid support (3) in a 3D printer. The printing nozzle (32) is advanced to contact and press the flexible substrate (2) and compress the compressible layer (33), and then traverses the flexible substrate when printed into the flexible substrate (2) from the 3D nozzle (32). The invention further discloses the 3D printer.

Description

[0001] The present invention relates to a method for 3D printing onto a flexible substrate and a 3D printer suitable for this purpose.

[0002] Our earlier application WO2022 / 223945 discloses a technique for 3D printing onto gloves to create protective features on the gloves. This invention relates to enhancements to that technique.

[0003] US2017 / 252980 and US2019 / 047221 disclose 3D printers with flexible attachments to a 3D printer bed. These are provided to facilitate the separation of the 3D printed article from the bed and to prevent damage to the printer nozzle.

[0004] US2021 / 0186154 disclosed the printing of foam.

[0005] According to the present invention, the method according to claim 1 is provided.

[0006] This invention utilizes a compressible layer into which the printing nozzle advances during printing to press against a flexible substrate. Typically, any contact between the printing nozzle and the object being printed is avoided, as contact could damage the article and / or the nozzle. However, in this case, any such damage is prevented by the presence of a compressible layer that compresses to accommodate the nozzle and allow it to press firmly against the flexible substrate.

[0007] The fact that the nozzle presses against the flexible substrate enhances the ability of the printed material to penetrate the flexible substrate, thereby improving the adhesion between the printed feature and the flexible substrate. This contrasts with US2017 / 252980 and US2019 / 047221, in which the 3D printing material does not penetrate the flexible substrate because the 3D printed article is specifically designed to be removed from the underlying layer. In US2021 / 0186154, foam is the printed article, therefore there is no compressible layer on the rigid support.

[0008] Furthermore, in prior art, the inner mold (last) supporting the glove is a metal that rapidly conducts heat away from the printed material. In this invention, the compressible layer insulates the area of ​​the flexible substrate onto which the material is printed. This slows down the curing process of the printed material, thereby further allowing it to penetrate into the flexible substrate. This provides a further improvement in bonding.

[0009] The flexible substrate can be any suitable material, such as leather or foam. Preferably, the flexible substrate is fabric. The substrate can be porous or have a rough surface to enhance the anchoring between the substrate and the printing material. With a rough surface, the 3D printing material can only penetrate into the substrate to a limited extent.

[0010] The compressible layer can be any suitable compressible layer, such as a compressible polymer. However, it is preferably foam because foam has well-controllable properties and provides a reasonable level of support for the flexible substrate when it is not deformed, but can be easily deformed through the nozzle. It also provides a good level of insulation, thereby enhancing the aforementioned advantages.

[0011] The compressible layer is preferably attached to the rigid support. This allows the flexible layer, which is 3D printed, to be more easily removed from the rigid support.

[0012] The compressible layer is preferably formed on top of the flexible layer thereon. This allows the printing nozzles to penetrate the compressible layer more easily.

[0013] 3D printing can be controlled to ensure that material printed from the 3D nozzle does not penetrate the compressible layer. This ensures that the flexible substrate does not bond to the compressible layer through the 3D printing material. To help ensure this is done more reliably, the compressible layer is preferably impermeable to the 3D printing material; for example, it can be a closed-cell foam.

[0014] Although this invention is advanced by improving the technology of WO2022 / 223945, in the field of gloves mounted on an inner mold, this invention can be applied to any situation where 3D printing on a flexible substrate is required.

[0015] For example, the rigid support could be the top of a platform or other surface below the nozzle of a 3D printer, on which the flexible substrate is clamped. Preferably, the rigid support is an inner mold, and the flexible substrate is stretched on the inner mold.

[0016] In the broadest sense, the above method can print only a single layer. However, to construct larger features, it is preferable to print additional layers. The method preferably also includes printing a first layer, wherein the nozzle compresses the compressible layer, and the nozzle is raised to space itself from the flexible substrate before printing another layer on top of the first layer. Printing the first layer using the above technique ensures good adhesion between the first layer and the article of manufacture. The feature is then constructed on top of this first layer in a conventional manner.

[0017] This invention can be applied to any article that requires 3D printing onto a flexible substrate. However, preferably, the flexible substrate is part of a glove.

[0018] The invention also extends to the 3D printer according to claim 7. In this case, the compressible layer is preferably foam, and the rigid support is preferably an inner mold.

[0019] The compressible layer is preferably attached to a rigid support. The compressible layer is closed-cell foam.

[0020] The nozzle is preferably movable to compress the compressible layer downward by at least 3%, more preferably at least 10%, and most preferably 20% of its uncompressed thickness. This indicates an intentional attempt to move the nozzle to compress the compressible layer to achieve the aforementioned effect.

[0021] An example of the method and 3D printer according to the present invention will now be described with reference to the accompanying drawings, in which:

[0022] Figure 1 It is through the cross-section of the 3D printer, where the printed object is in place;

[0023] Figure 2 This is a perspective view of the inner mold;

[0024] Figure 3 It is a plan view of the inner mold;

[0025] Figure 4 It is a cross-section of a portion of the inner mold of the in-place glove;

[0026] Figure 5 It is a cross-section showing the interaction between the printing nozzle and the article / mold;

[0027] Figure 6 Similar to Figure 4 This shows an alternative version of the inner mold.

[0028] Figure 1 The 3D printer shown is taken from WO 2022 / 223945, which represents a type of printer suitable for use in this invention.

[0029] like Figure 1 As shown, multiple protective features 1 are printed onto a glove body 2, which is stretched on an inner mold 3. Features 1 are preferably formed from a relatively soft polymer such as TPU.

[0030] The inner mold 3 is placed on a base plate 12 having a hook-like structure 20 to position the inner mold relative to the edge of the print bed 21. Alternatively or additionally, locating pins may be provided in the base plate 12, which align with holes in the print bed 21 to aid in positioning. The 3D printer has a print head 30, which is supported on a frame 31 for movement in a horizontal plane to eject printing material from a nozzle 32. The nozzle 32 is vertically movable.

[0031] Further details regarding the printer and inner mold are provided in WO2022 / 223945.

[0032] This invention relates to the adaptation and printing technology of an inner mold 3. The inner mold 3 is covered with a foam layer 33, which extends across almost all the upper surface of the inner mold 3 on which printing is performed. Figure 4As shown, the end of the foam layer 33 can be slightly shorter than the edge of the inner mold 3 in order to reduce the chance that the edge of the foam layer 33 will get stuck on the glove body 2 when the glove body 2 is placed on the inner mold 3.

[0033] The presence of foam layer 33 allows for a novel approach. In particular, as... Figure 5 As shown, nozzle 32 advances to the position where it presses against the glove body 2 and compresses the foam layer 33. This is the position where nozzle 32 prints the first layer of polymer. Because nozzle 32 presses very firmly against the glove body 2, the polymer penetrates deeper into the glove body 2 when injected from nozzle 32. Since the foam layer 33 provides a level of insulation above the inner mold 3, the polymer will remain fluid for a longer time, thus also enhancing penetration into the body 2.

[0034] Once the first layer is completed, nozzle 32 is withdrawn to a more conventional position where the nozzle does not contact the glove body 2, but is very slightly spaced from it, so that additional polymer layers can be printed onto the previously formed base layer in a conventional manner.

[0035] Figure 6 The inner mold 3 has a different construction, in which a groove 34 is formed around the edge of the inner mold 3. The glove will typically 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 inner mold 3.

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 having a print nozzle; advancing the print nozzle towards the flexible substrate to contact and press the flexible substrate and compress the compressible layer; and while in that position, traversing the print nozzle across the flexible substrate and printing from the 3D nozzle into the flexible substrate.

2. The method of claim 1, wherein, the flexible substrate is a fabric.

3. The method of claim 1 or 2, wherein, the compressible layer is a foam.

4. The method of any preceding claim, wherein, the rigid support is an inner mold and the flexible substrate is stretched over the inner mold.

5. The method of any preceding claim, wherein, the method comprises printing a first layer with the nozzle, compressing the compressible layer and raising the nozzle to be spaced apart from the flexible substrate before printing another layer on top of the first layer.

6. The method of any preceding claim, wherein, the flexible substrate is part of a glove.

7. The method of any preceding claim, wherein, the compressible layer is attached to the rigid support.

8. The method of any preceding claim, wherein, the compressible layer forms the uppermost layer on which the flexible layer is mounted.

9. The method of any preceding claim, wherein, the compressible layer is impermeable to the 3D printing material.

10. The method of claim 9, wherein, the compressible layer is a closed cell foam.

11. The method of any preceding claim, further comprising: the nozzle is moved to vertically compress the compressible layer by at least 3%, preferably at least 10%, and more preferably 20% of its uncompressed thickness.

12. A 3D printer, the 3D printer comprising a print bed formed by a rigid support, the rigid support being covered by a top layer which is a compressible layer, the printer further comprising a print nozzle, the nozzle being movable downwards into the compressible layer to compress the compressible layer.

13. The 3D printer of claim 12, wherein, the compressible layer is a foam.

14. The 3D printer according to claim 12 or 13, wherein, the rigid support is an inner mold.

15. The 3D printer according to any one of claims 12 to 14, wherein, the compressible layer is attached to the rigid support.

16. The 3D printer according to any one of claims 12 to 15, wherein, the compressible layer is a closed cell foam.

17. The 3D printer according to any one of claims 12 to 16, wherein, the nozzle is movable to vertically compress the compressible layer by at least 3%, preferably at least 10%, and more preferably 20% of its uncompressed thickness.

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