METHOD FOR MANUFACTURING A CONTAINER PREFORM USING ADDITIVE MANUFACTURING

Abstract

The method for manufacturing a preform intended for creating a container comprises: - a step 34 of transferring a digital model of the preform that is to be manufactured to an additive manufacturing machine, - a step 36 of producing the preform using the additive manufacturing machine from the transferred digital model, and - a step 38 of cooling the manufactured preform at ambient temperature.

Claims

1. Method for manufacturing a preform intended for creating a container, characterized in that it comprises: a step (34) of transferring a digital model of the preform that is to be manufactured to an additive manufacturing machine, a step (36) of producing the preform using the additive manufacturing machine from the transferred digital model, and a step (38) of cooling the manufactured preform at ambient temperature.

2. Method according to claim 1, further comprising, before the step (34) of transferring the digital model of the preform that is to be manufactured, a step of creating said digital model.

3. Method according to claim 1, wherein the step (36) of producing the preform by additive manufacturing is obtained by depositing a fused material.

4. Method according to claim 1, wherein the step (36) of producing the preform by additive manufacturing is obtained using a jet of material.

5. Method according to claim 1, wherein the step (36) of producing the preform by additive manufacturing is obtained by sintering material using at least one beam of energy.

6. Preform for manufacturing a container by blow-moulding and produced by additive manufacturing, comprising a body (12) of elongate overall shape and provided with an open first end forming a neck (14) and with a closed second end forming a bottom (16).

7. Preform according to claim 6, internally provided with at least one protrusion (22, 24) formed as an integral part of the body (12), and/or with a groove, the transverse section of which is delimited by an outline comprising an undercut.

8. Preform according to claim 6, wherein the inner diameter of the neck (14) of the body is less than or equal to 8 mm.

9. Preform according to claim 6, wherein the exterior surface of the body (12) comprises patterns and/or markings.

10. Preform according to claim 6, wherein the body (12) is formed of several materials.

11. Preform according to claim 6, wherein the body (12) has regions of different colours.

12. Method for manufacturing a container, comprising: a step of manufacturing a preform according to the method of claim 1, a step (40) of heating the manufactured preform to between the glass transition temperature and the crystallization temperature of the material of the preform, a step (46) of biaxial stretching of the preform in the radial direction and in the axial direction inside a blow-moulding mould, and a step (48) of extracting the container formed from the blow-moulding mould.

13. Container for storing a product, notably a cosmetic product, obtained according to the manufacturing method of claim 12.

Description

[0042] The present invention will be better understood from studying the detailed description of embodiments that are given by way of entirely non-limiting examples and are illustrated by the appended drawings, in which:

[0043] [FIG. 1] is a front view of a preform according to a first exemplary embodiment of the invention,

[0044] [FIG. 2] is a view in cross-section on the line II-II of FIG. 1.

[0045] [FIG. 3] is a flowchart of the method for manufacturing the preform of FIGS. 1 and 2 according to one exemplary embodiment of the invention,

[0046] [FIG. 4] is a flowchart of the method for manufacturing a container from the preform of FIGS. 1 and 2 according to one exemplary embodiment of the invention,

[0047] [FIG. 5] is a front view of a container obtained according to the manufacturing method of FIG. 4 from the preform of FIGS. 1 and 2,

[0048] [FIG. 6] is a view in cross-section on the line VI-VI of FIG. 5, and

[0049] [FIG. 7] is a front view of a container obtained according to the manufacturing method of FIG. 4 from a preform according to a second exemplary embodiment of the invention.

[0050] FIGS. 1 and 2 depict a preform, designated by the general numerical reference 10, which is intended for the manufacture, by blow-moulding, of a container for storing a product.

[0051] As will be described in greater detail later, the preform 10 is produced by additive manufacturing.

[0052] The container preform 10 is depicted in a position presumed to be vertical and extends along a longitudinal axis X-X′ of elongation. The preform 10 is produced in a single piece, for example made of polyethylene terephthalate (PET). Alternatively, the preform 10 could be produced in other materials, for example polycarbonate (PC).

[0053] The preform 10 comprises a body 12 of axis X-X′. The body 12 comprises an open end forming a neck 14, and an opposite closed end forming a bottom 16. Between the neck 14 and the bottom 16, the body 12 has a lateral wall 18 of substantially cylindrical shape.

[0054] The neck 14 of the preform is manufactured to the finished dimensions of the container. The neck 14 is equipped in this instance on the outside with a snap-fastening hook 20 of annular shape to allow the attachment of a product-dispensing member or of a closure cap, once the container has been manufactured from the preform 10. As a variant, it is possible, instead of the annular hook, to provide a plurality of hooks spaced apart from one another in the circumferential direction, or else other types of retaining member, for example a screw thread.

[0055] The neck 14 and the bottom 16 axially delimit an internal volume 22 of the preform. The bottom 16 in this instance is domed. In a variant, the bottom 16 may have other forms, for example may be flat.

[0056] In the exemplary embodiment illustrated, the lateral wall 18 of the preform is internally equipped with two annular ribs 24, 26 extending radially into the internal volume 22. The ribs 24, 26 are axially spaced. The ribs 24, 26 may be continuous or discontinuous in the circumferential direction.

[0057] In the exemplary embodiment illustrated, the rib 24 has, in cross section, a triangular shape, and the rib 26 has a rounded shape. In a variant, the rib or ribs 24, 26 may have other shapes, for example polygonal, notably square, rectangular, hexagonal, etc.

[0058] As indicated previously, the preform 10 is produced by additive manufacturing. The steps of the method that leads to the obtaining of the preform 10 will now be described with reference to FIG. 3.

[0059] In a first step referenced 30, the 3-D digital model of the preform that is to be manufactured is created. The digital model is created from modelling software, for example computer aided design (CAD) software. The digital model may be generated in a standard file format such as the STL (“STereoLithography”) format.

[0060] Next, in a second step 32, the digital model formulated is sliced into a plurality of successive layers by slicing software also known as a slicer. The slicing software may be the same software as the CAD software used for creating the digital model of the preform, or else may be separate software.

[0061] Then, in a third step 34, the created and sliced digital model is transferred to an additive manufacturing machine. The digital model is transferred to a control unit of the additive manufacturing machine.

[0062] The additive manufacturing machine may for example employ fused material deposition technology. In a way known per se, in that case, the additive manufacturing machine chiefly comprises a printing platform on which the preform is intended to be printed, a spool of filament which serves as print material, and an extrusion head which melts and conveys the filament in order to form the preform.

[0063] Alternatively, it is possible to use another type of additive manufacturing machine, for example a machine employing technology involving jets of material in the form of droplets. In that case, a liquid resin is heated inside a receptacle of the machine to the viscosity suitable for printing, and is then sprayed by a print head, in the form of microdroplets, onto a printing platform and solidified by photopolymerization using a light source incorporated into the print head in order to obtain the preform.

[0064] As a variant, it is alternatively possible to use other types of additive manufacturing machine, for example a stereolithography machine, or else an additive manufacturing machine that sinters powder using at least one beam of energy. In this last instance, the machine comprises a powder-spreading means, for example a roller, a platform on which the powder is deposited, and at least one laser beam for sintering and consolidating the powder in order to form the preform.

[0065] Whatever the type of technology employed by the sintering machine, the preform is manufactured in step 36 by the solidification of the successive layers of the digital model transferred to the sintering machine.

[0066] Finally, in a fourth step 38, the preform obtained by additive manufacturing is cooled at ambient temperature.

[0067] In the manufacturing method which has just been described, the step of additive manufacturing of the preform immediately follows the steps of creating the digital model thereof and of slicing this model. In another embodiment, the manufacturing method may begin from the additive manufacturing of the preform when the digital model and the slicing have been achieved beforehand.

[0068] The steps of the method for manufacturing the storage container from the preform obtained beforehand by additive manufacturing will now be described with reference to FIG. 4.

[0069] After the manufacture of the preform as indicated hereinabove, the method for manufacturing the container comprises a step 40 of heating this preform in the solid state to a temperature which is higher than the glass transition temperature of the material of the preform and lower than the crystallization temperature.

[0070] This heating step 40 may for example be performed in an infrared radiation oven.

[0071] In a successive step 42, the heated preform is introduced into a blow-moulding mould.

[0072] Next, in a step 44, a stretch rod is introduced into the preform in such a way that the free end of this rod comes to press axially against the bottom of the preform.

[0073] Then, in a step 46, the preform is biaxially stretched in the radial direction by blowing a pressurized gas, for example, air, into it, and in the axial direction by the stretch rod which applies axial pressure to the bottom of the preform. The preform 10 is biaxially stretched to make it conform to the internal walls of the blow-moulding mould which have the desired container shape.

[0074] During this step 46 of biaxial stretching of the preform, the neck of the preform is held captive in the blow-moulding mould so that neither its shape nor its dimensions are modified.

[0075] Finally, in a last step 48, the container formed is extracted from the blow-moulding mould.

[0076] In the example which has just been described, the preform is stretched in the axial direction by the stretch rod. Alternatively, the preform could be stretched in the axial direction by a blow-moulding rod which then performs a dual function: exerting axial pressure on the bottom of the preform by pressing, and introducing gas into the latter to stretch it in the radial direction.

[0077] The container 50 which is manufactured from the preform 10 of FIGS. 1 and 2 according to the method described hereinabove is depicted in FIGS. 5 and 6.

[0078] On leaving the blow-moulding mould, the neck 14 of the container is separated from the periphery of the container 50 by an annular shoulder 52 oriented axially upwards.

[0079] As indicated previously, the preform of the container 50 has been obtained beforehand using additive manufacturing. Because the preform has been produced by solidifying successive layers, its shape may exhibit contours with an undercut which can thereafter be found again in the finished container.

[0080] In the exemplary embodiment illustrated, the container 50 internally comprises the ribs 22, 24 which have been formed on the preform. The shape of the preform, and therefore the final shape of the container 50, are not restricted to those illustrated in the figures, which are given purely by way of illustration.

[0081] Creating the preform using additive manufacturing makes it possible locally to obtain complex shapes, and also to manufacture preforms with aesthetic shapes that are completely different from those imposed by the injection-moulding technique, and to do so at a low cost of manufacture.

[0082] It is also possible to provide on the exterior surface of the preform patterns in an ordered or disordered arrangement, which are then found again on the container 50 as illustrated for example in FIG. 7 in which elements that are identical bear the same references.

[0083] With additive manufacturing, it is also possible to provide on the exterior surface of the preform one or more markings that create a contrast effect. The marking or markings may exhibit a brightness and/or roughness different from that of the rest of the preform. The marking or markings may also be letters and/or symbols and/or figures and/or distinctive information of the brand of the product intended to be packaged in the finished container.

[0084] It is alternatively possible to create the preform with different materials, for example to have on the finished container soft regions promoting grip intended to be grasped by the user, and harder regions.

[0085] In addition, with manufacturing by sintering, it is also possible to envisage a preform provided with regions of different colours, for example by using the same or different materials. It is possible to use synthetic or metallic materials.

[0086] Furthermore, compared with producing the container directly using additive manufacturing, producing a container by blow-moulding a preform obtained beforehand by additive manufacturing makes it possible to obtain a container that has properties, notably mechanical properties, tailored to its use.