Apparatus and method for manufacturing a component made of plastic material, and a component made of plastic material

Abstract

The embodiments described herein relate to a method and apparatus for manufacturing a plastic member suitable for use as a housing for a household appliance or as a receptacle, the member comprising a first layer and a second layer covering at least a portion of the first layer. The method for manufacturing a plastic member (10) suitable for forming a housing for a household appliance (50) or a receptacle, the plastic member (10) having at least one transparent region (T), comprises injecting an opaque first plastic material into a first mold volume (V1) defined between a punch (29) and a first receiving die (30) having a first molding surface (33) to form an inner first layer (11), and restricting at least a portion of the first mold volume (V1). a first injection step for forming an exposed region (S) in the first layer (11) by injection of an at least partially transparent second plastic material into a second molding volume (V2) defined between the first layer (11) obtained in the first injection step, a punch (29) and a second receiving mold (34) to produce a second layer (12) and cover the exposed region (S) with the second plastic material to produce a transparent region (T) in the part (10).

Description

[Technical Field]

[0001] The embodiments described herein relate to an apparatus and method for manufacturing a component having a body made of a plastic material with at least one transparent area, such as a window or peripheral strip, through which the interior of the body itself can be viewed.

[0002] Such a component is particularly suitable for use as a container or housing for a household appliance such as a kettle, a toaster, a vacuum cleaner, a coffee machine, a blender or an iron.

[0003] The invention also relates to a component made of plastic material and to a household appliance or receptacle comprising such a component. [Background technology]

[0004] In the field of household appliances, it is known to manufacture components or finished objects having two or more layers of plastic material that at least partially overlap one another to provide a defined aesthetic appearance. Such components can be used to form the exterior structure of, for example, household appliances or articles or objects such as carafes, bowls, and the like, but the examples of such articles or objects are not limiting.

[0005] It is also known that there is an increasing focus on aesthetic research in the design and manufacture of household appliances to satisfy consumer preferences, in order to provide an attractive and recognizable aesthetic appearance and stand out from similar solutions on the market.

[0006] For example, a component that serves as the container for a kettle is known, which comprises a first layer of a transparent plastic material and a second layer of a metal material, with multiple through-holes formed in the second layer through which the first layer and, by extension, the interior of the kettle itself can be seen.

[0007] However, this solution requires that the first and second layers be fabricated separately and then subsequently bonded together to join them together, which creates problems with bonding and sealing between them.

[0008] It is also known to create transparent areas, for example windows and / or lenses, in the housing of kettles and other household appliances to allow viewing of the interior of the product or controls.

[0009] One problem with creating such transparent areas is that proper sealing of the window or lens must be ensured to prevent the escape of liquids, vapors and / or dust.

[0010] Additionally, other functional parts, such as a spout, may be made from a different material than the main body for aesthetic reasons, or may be made separately from the main body.

[0011] One problem associated with the coupling of additional functional parts is the need to ensure a hermetic seal of said additional functional parts to avoid leakage or infiltration of liquids between the various hollow spaces.

[0012] Known solutions involve creating a component made of a transparent material, placing it in a mold, and then injecting a second, opaque material to create a body incorporating the transparent component. This solution, along with the need for a dedicated mold, can result in defects at the interface between the transparent component and the injected material, which can detract from the aesthetic appearance of the component and result in product waste and manufacturing waste.

[0013] Also known is a solution in which a container is made with an opening or slot of a shape corresponding to the window to be made, and then an element made of a transparent material, already made by molding or other techniques, is inserted into the opening or slot and attached to the container, this transparent material generally being a plastic material or glass, and the transparent element has a shape suitable for closing the opening.

[0014] Alternatively, openings or slots that can accommodate the transparent member can be created by chip removal machining methods, and the cost of equipping the machine to perform such machining can be prohibitive.

[0015] The transparent member, or generally multiple functional members made of dissimilar materials, can be attached by mounting or sealing members, glued together with adhesives, or heat-welded by various techniques such as ultrasonic welding, vibration welding, or induction welding.

[0016] The above approaches require long assembly times due to the large number of process steps, including manual steps, and require particularly costly measures to ensure a hermetic seal of the window.

[0017] Another drawback is that the assembly process of the components that make up the window can destroy the components themselves, impair their transparency, or even scratch the components.

[0018] Another drawback is that during the assembly process, the openings in the molded member and the transparent member may not be perfectly complementary or aligned, resulting in manufacturing waste or causing liquid and / or dust leakage into the finished product.

[0019] U.S. Patent Application Publication No. 2004 / 0227271 discloses a method and apparatus for producing two-color key caps for various types of electronic devices. U.S. Patent Application Publication No. 2004 / 0227271 describes a molding tool in which both the punch and die have protrusions. These protrusions contact each other in a first step of injecting a first material to form an empty space in the first layer. This empty space is then filled with a second material to form a second layer, which covers the first layer in the second injection step. This second material does not fill the entire thickness of the empty space in the first layer, but only a portion of it. That is, it fills up to the point where the second material contacts the protrusion of the punch. The solution described in U.S. Patent Application Publication No. 2004 / 0227271 is suitable for very small components, such as the size of a key or button, and has the disadvantage of not being able to produce a completely transparent window. This is because during the first injection step the punch and die come into contact over the entire dimension of the open space, which can damage the punch and cause scratches on the surface, which will then be imprinted on the second layer and remain visible.

[0020] EP 1 568 460 A1 discloses a method and apparatus for creating a plurality of different sections in a mould which can then be filled with different materials, in effect providing each section with a layer of material.

[0021] Therefore, there is a need to develop an apparatus and method for manufacturing a part made of a plastic material having at least one transparent area or window, which apparatus and method overcomes at least one of the drawbacks of the prior art.

[0022] Another object of the present invention is to complete an apparatus and method capable of producing a member having a highly transparent area or window that is substantially free of scratches or processing marks.

[0023] Another object of the present invention is to provide an apparatus and method for manufacturing a component having a transparent window that is completely hermetically sealed to prevent any leakage from the inside to the outside or from the outside to the inside.

[0024] Another object is to provide an apparatus and method for manufacturing plastic components that allows high productivity and efficiency at high speeds while significantly reducing production waste due to windows that are not sealed or have defects that impair the transparency of the windows.

[0025] Another object is to complete a highly efficient and economical method for manufacturing components made of plastic materials, which can achieve high productivity while keeping overall costs down.

[0026] The applicant has devised and tested to overcome the shortcomings of the prior art and to achieve these and other objects and advantages and has thus achieved the present invention. Summary of the Invention

[0027] The invention is defined in the independent claims, which describe its features, while the dependent claims describe other features of the invention or variants of its main inventive idea.

[0028] In accordance with the above objectives, the present invention relates to a method and an apparatus for manufacturing a component made of a plastic material suitable for forming a housing, a housing, a shell, an external structure and / or an external body of a household appliance, or at least a part thereof.

[0029] Examples of applications of the components of the present invention may include household appliances such as kettles, toasters, vacuum cleaners, electric brushes, blenders, microwave ovens, electric ovens, fryers, teapots, coffee machines, ice cream makers, kneaders, and hair dryers.

[0030] The component of the present invention has a body made of a plastic material with a first inner layer of a first material and a second outer layer of a second material covering at least a portion of the first inner layer.

[0031] In some embodiments, the second layer covers the entire first layer.

[0032] In some embodiments, the first material can be opaque, or one color, or multiple colors, and the second material can be at least partially transparent, allowing the opaque first layer to be visible through the second material, which can give the final part a partially convex, three-dimensional appearance.

[0033] In some embodiments, the component has at least one transparent region integrally formed with the body of the component, the transparent region being defined by a transparent second material, the transparent region extending into and / or above the exposed region of the inner first layer.

[0034] In some embodiments, the transparent region can be formed in the shape of a transparent window. Providing a transparent window made directly from the transparent second material can increase the speed at which the product can be manufactured, while reducing both the processing operations and the number of molds and storage space required.

[0035] Furthermore, since the window is made continuous with the outer surface of the component, there is no bond line between the internal and external environments, thus ensuring a perfect hermetic seal of the window.

[0036] In other embodiments, the transparent outer second layer extends beyond the edge of the inner first layer in at least the axial direction, resulting in the member having a transparent peripheral strip, which provides the effect of transparency and brightness.

[0037] In some embodiments, the outer second layer extends beyond the edge of the inner layer, i.e., corresponds to the exposed area without overlapping with the first layer, and may itself form one or more transparent portions of the body of the component, for example forming a spout or handle in the case of a kettle or carafe, or other decorative feature.

[0038] An apparatus for manufacturing a member of the present invention comprises a first molding assembly having a punch, a first receiving die, and a first injection unit; and a second molding assembly having a second receiving die and a second injection unit, wherein the punch has a contrasting surface, the first receiving die has a first molding surface adapted to define a first molding volume between the punch and the first receiving die, the first injection unit being configured to inject a first plastic material into the first molding volume, and the second receiving die has a second molding surface adapted to define a second molding volume together with the first inner layer of the member and the punch, and the second injection unit being configured to inject a second plastic material into the second molding volume.

[0039] In some embodiments, at least one of the first receiving die or punch includes at least one coupling protrusion that confines at least a portion of the first molding volume to form at least one exposed area in the first layer, and the second molding volume extends within the at least one exposed area of ​​the first layer.

[0040] In another embodiment, the at least one coupling protrusion has a protruding abutment portion that, in use, contacts either the contrast surface of the punch or the first molding surface of the first receiving die to restrict the first molding volume and form an empty space or cavity between the punch and the first molding surface corresponding to the exposed area, thereby maintaining the punch and the first molding surface separated and not in contact with each other.

[0041] This embodiment allows the same punch to be used to manufacture the part in both the first and second layer steps, while still maintaining brightness, thereby achieving high speed and productivity while ensuring high transparency in the transparent region.

[0042] This becomes even more effective when the coupling projection is provided on the first forming die.

[0043] Embodiments described herein also relate to a method for manufacturing a component, the method comprising: a first injection step of injecting an opaque first plastic material into a first molding volume defined between the punch and a first receiving die having a first molding surface to create a first layer and restricting at least a portion of the first molding volume to form an exposed area in the first layer; a second injection step in which an at least partially transparent second plastic material is injected into a second molding volume defined between the first layer obtained in the first injection step, the punch and the second receiving mold to produce a second layer, and the exposed areas of the first layer are covered with the second material to produce transparent areas; It has.

[0044] In another embodiment, during the first injection step, at least one protruding abutment portion of the first receiving die or the coupling protrusion of the punch is positioned to contact at least one of the contrasting surface of the punch or the first molding surface, thereby limiting the first molding volume and forming an empty space or cavity between the punch and the first molding side corresponding to the exposed area, thereby maintaining the punch and the first receiving die in an isolated state and ensuring the brightness and gloss of the contrasting surface of the punch.

[0045] These and other aspects, features and advantages of the present invention will become apparent from the following description of some embodiments, which are provided by way of example rather than limitation, and which are considered in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0046] [Figure 1] 1 is a schematic diagram of components of an embodiment of the present invention applied to a household appliance, the household appliance shown in this example being a kettle. [Figure 2] FIG. 2 is a cross-sectional view taken along the line II-II in FIG. [Figure 3] FIG. 3 is an enlarged detail view of a portion of FIG. 2. [Figure 4] 1 is a schematic diagram of components of another embodiment of the present invention applied to another household appliance, in this case the other household appliance being a toaster. [Figure 4a] FIG. 10 is a three-dimensional view of a detail of a component of another embodiment of the present invention. [Figure 4b] FIG. 10 is a three-dimensional view of a portion of a member of another embodiment. [Figure 4c] FIG. 10 is a three-dimensional view of a portion of a member of another embodiment. [Figure 5] 1 is a schematic diagram of an apparatus for manufacturing components made of plastic material according to some embodiments. [Figure 6] 1 is a vertical cross-sectional view of the element of the invention at the end of the first step of injecting the first material; FIG. [Figure 7] 3 is a vertical cross-sectional view of the element of the invention at the end of the second step of injecting the second material; FIG. [Figure 8] FIG. 6 is an enlarged detail view of the apparatus of FIG. 5 during the first injection step. [Figure 9] 9 is a cross-sectional view of the device of FIG. 5 taken along section line IX-IX. [Figure 9a] FIG. 10 is an enlarged detail view of FIG. [Figure 10] FIG. 7 is a cross-sectional view taken along line XX in FIG. 6. [Figure 11] 10 is a cross-sectional view of the device of FIG. 5 taken along section line XI-XI. [Figure 12] A cross-sectional view taken along line XII-XII in Figure 7. DETAILED DESCRIPTION OF THE INVENTION

[0047] Reference will now be made in detail to possible embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings, each example being provided by way of illustration of the invention and not to be construed as limiting the invention.

[0048] Before describing these embodiments, it should be made clear that the present invention is not limited in its application to the precise construction and arrangement of parts set forth in the following description, which refers to the accompanying drawings. The following description may provide other embodiments, and may be produced or carried out in various other ways. It should also be made clear that the words and terminology used herein are for descriptive purposes only and should not be construed as limiting the present invention.

[0049] The accompanying drawings are used to illustrate an embodiment of an element 10 made of a plastic material suitable for constituting a housing, a shell, an external structure and / or an external body of a household appliance 50, or at least a part thereof, or other object such as a bowl, a carafe, a thermos, etc.

[0050] In the following description, household appliances such as a kettle 50A and a toaster 50B are used as examples, however it is understood that the component 10 of the present invention can be a housing or a housing for other types of household appliances such as a vacuum cleaner, an electric brush, a blender, a microwave oven, an electric oven, a fryer, a teapot, a coffee machine, an ice cream maker, a kneader, a hair dryer, an iron, etc.

[0051] The component 10 of the present invention comprises an inner, first layer 11 and a second, outer layer 12 at least partially overlapping the inner, first layer 11 .

[0052] In some embodiments, the member 10 comprises only two layers: a first layer 11 and a second layer 12 .

[0053] In a preferred embodiment, the first layer 11 and the second layer 12 may be made of a plastic material, such as a heat resistant polymeric material.

[0054] In a possible embodiment, the first layer 11 and the second layer 12 may be made of materials with similar properties and characteristics.

[0055] In a possible embodiment, the first layer 11 and the second layer 12 may be made of materials with dissimilar properties and characteristics.

[0056] In some embodiments applicable to, for example, household appliances for food processing, the first layer 11 and the second layer 12 may be made of a resin suitable for food applications, such as polypropylene.

[0057] In a possible embodiment, only the first layer 11 is suitable for food applications, whereas the second layer 12 is not suitable for such applications.

[0058] In other embodiments, depending on the application, the first layer 11 and / or the second layer 12 can be made of thermoplastic resins of different properties.

[0059] In some embodiments, the first layer 11 can be made of an opaque first material or of a single or multiple colors, and the second layer 12 can be made of an at least partially transparent second material, allowing the inner opaque first layer 11 to be visible through the second material.

[0060] A layer is transparent or translucent if it allows optical radiation to pass through the entire thickness of the layer, allowing objects located beyond the layer to be visible.

[0061] This gives the final part 10 a partially convex, three-dimensional appearance.

[0062] In some embodiments, the first layer 11 and the second layer 12 can be made by a two-component injection molding process.

[0063] In some embodiments, the outer second layer 12 covers the entire inner first layer 11 .

[0064] In some embodiments, the component 10 has at least one transparent region T made integrally with the body of the component 10, the transparent region T being made directly from a second transparent material.

[0065] As will be more clearly explained below, the at least one transparent region T can be produced by creating a first layer 11 having at least one exposed region S and filling this exposed region S with a second transparent material.

[0066] In some embodiments, the at least one transparent region T may form a window 22, a peripheral strip 25, or some part of the member 10, such as the spout 51 or the handle 52 in the case of the kettle 50A.

[0067] Since the inner first layer 11 is absent corresponding to the transparent region T, the outer second layer 12 substantially fills the exposed region S of the inner first layer 11, thereby forming a part of the inner surface 13 of the member 10 in continuity with the first material.

[0068] A transparent window 22 allows the user to see through it.

[0069] For example, in the case of kettle 50A, transparent window 22 allows a user to view the level of water contained in the container made of member 10. In such a case, transparent window 22 may extend vertically along the container of kettle 50A.

[0070] In other applications, window 22 may be configured to allow the user to view other possible features of the home appliance, such as the thermostat or timer of toaster 50B.

[0071] In other embodiments, the window 22 may allow a user to view possible internal parts of the household appliance 50 and / or to view products being cooked or the accumulation of dust in the dust collection bin of a vacuum cleaner.

[0072] As mentioned above, the window 22 can be made directly by the outer transparent second layer 12 .

[0073] In particular, the first layer 11 may have an opening 21 or slot having substantially the same shape as the shape of the window 22 that is to be made.

[0074] In fact, the second layer 12 covering the first layer 11 may be continuous with the outer surface 15 and may fill and completely cover the openings 21 or slots.

[0075] In a possible solution, the component 10 may have a different surface finish on the outer second layer 12 depending on the window 22, such as a substantially flat, smooth finish, to allow for better visibility through the window 22.

[0076] The window 22 made in this way has the advantage that it does not require any specific assembly or any packing or other device that can guarantee its airtight seal. In fact, the window 22 made in this way guarantees maximum sealing, preventing any liquid, vapor or dust that may be inside the domestic appliance from leaking from the inside to the outside, and vice versa.

[0077] In another possible embodiment, the second layer 12 has an outer edge 23 which extends beyond the inner edge 24 of the first layer 11 in the axial direction X.

[0078] Specifically, in this embodiment, a portion of the second layer 12 actually protrudes from the first layer 11 in the axial direction.

[0079] Thus, the component 10 has a transparent area T defined by a single-layer peripheral strip 25 made of the second material. This transparent peripheral strip 25 gives the component 10 a bright, three-dimensional appearance.

[0080] In other embodiments, the second layer 12 can extend to the body of the member 10 in other parts, such as the spout 51 or handle 52 of the kettle 50A, thereby forming other transparent areas T to provide an even lighter feel.

[0081] In some embodiments, the first layer 11 has a first thickness S1 and the second layer 12 has a second thickness S2 that is greater than the first thickness S1.

[0082] In some embodiments, the first thickness S1 and the second thickness S2 can be defined as the maximum thickness of each layer.

[0083] Advantageously, the ratio of the second thickness S2 of the second layer 12 to the first thickness S1 of the first layer 11 may be in the range of 1.05-2.5, more preferably in the range of 1.1-2.

[0084] The first layer 11 has a first surface 13 which forms the inner surface of the member 10 and faces the interior of the household appliance 50 when in use.

[0085] In the case of kettle 50A, first surface 13 may itself be the interior surface of the water compartment.

[0086] The first layer 11 also has a second surface 14 opposite the first surface 13, with an outer second layer 12 disposed in contact with the second surface 14.

[0087] In some embodiments, the inner first surface 13 can have a smooth, uniform transition without any irregularities.

[0088] The second layer 12 has an outer surface 15 opposite the inner surface 13, which in use becomes the outer surface of the component 10 and thus the outer surface of the household appliance 50 to which the component 10 is applied.

[0089] In some embodiments, the exterior surface 15 has a three-dimensional finish and has at least a portion thereof having a plurality of aesthetic reliefs 16 protruding therefrom, the reliefs 16 being adapted to give the component 10 a pleasing aesthetic appearance.

[0090] The relief in the examples of possible embodiments shown, for example, in Figures 1, 2, 3, 4, 4a and 4b, can include a plurality of parallel ribbed, bubble, hemispherical, diamond-like features, or other geometric or non-geometric aesthetic relief 16.

[0091] In particular, the outer surface 15 has alternating protrusions 17 and recesses 18 which give the member 10, and the household appliance 50 as a whole, a three-dimensional appearance.

[0092] In some embodiments, protrusions 17 and recesses 18 each correspond to areas of different thickness on inner surface 13 of member 10 .

[0093] In a possible embodiment, the projections 17 are formed as vertical ribs that are substantially parallel to and adjacent to one another.

[0094] Possible variations include horizontally or obliquely arranged ribs or projections or reliefs with a helical or spiral progression.

[0095] In another embodiment shown in FIG. 4a, the protrusions 17 may be formed as adjacent hemispheres or bubble portions distributed evenly or in a desired arrangement.

[0096] In another embodiment shown in FIG. 4b, the protrusions 17 can be formed in the shape of a polygonal pyramid, and in the case of the rectangular type in this example, can be formed side by side.

[0097] In other variants not shown, the relief 16 can have other shapes and can also have non-geometric shapes, for example, a flower shape, a heart shape, etc.

[0098] In some embodiments, the member 10 can have a cylindrical shape.

[0099] The cross section of member 10 may be circular, polygonal, or elliptical, or may have a perimeter that combines straight and curved sections, depending on the desire or application.

[0100] Furthermore, the cross section of the member 10 may be constant or variable along its axial progression, and may have concave or convex portions.

[0101] In other embodiments, member 10 may be open curved and configured to connect to other similar members 10 to form a housing or enclosure for household appliance 50, or to connect to different members to form a housing or enclosure.

[0102] In some embodiments, the inner first layer 11 has fill passages or cavities 19 formed in its thickness.

[0103] The shape and location of the fill passage or cavity 19 corresponds to the shape and location of the recess 18 in the outer surface 15 .

[0104] In particular, the filling cavities 19 can be made in the thickness of the first layer 11 corresponding to the second surface 14 so as to follow the shape of the outer surface 15 of the outer second layer 12 formed by the aesthetic relief 16, i.e., the shape of the outer surface 15 of the outer second layer 12 formed by alternating protrusions 17 and recesses 18.

[0105] Advantageously, the filling cavity 19 is able to compensate at least partly for the difference in thickness between the protrusions 17 and the recesses 18 .

[0106] In other words, at least in the areas where the inner first layer 11 is also present, the outer second layer 12 is of a substantially constant thickness along the lateral dimension of the member 10, or in any case of a substantially constant average thickness, except for small deviations from the average value, for example of 10-20%.

[0107] The inner first layer 11 has a varying average thickness across the member 10 .

[0108] In some embodiments, the transition region 20 sandwiched between the portion of the second surface 14 having the fill cavity 19 and the portion of the second surface 14 not having the fill cavity 19 can be beveled, as shown in FIG. 3, for example.

[0109] Advantageously, the beveled transition region 20 can prevent or at least reduce heat concentration during the step of injecting the second material to create the second layer 12, and thus can prevent or at least reduce undesired remelting of the first material that creates the first layer 11.

[0110] In this way, erosion due to mechanical rubbing caused by the flow of the second material is also reduced.

[0111] The embodiment now described with reference to FIGS. 5 to 12 also relates to an apparatus 26 for manufacturing the component 10. As shown in FIG.

[0112] The apparatus 26 includes a first mold assembly 27 configured to produce the first layer 11 and a second mold assembly 28 configured to produce the second layer 12 .

[0113] In one embodiment of apparatus 26, first mold assembly 27 is positioned adjacent and proximate to second mold assembly 28.

[0114] In some embodiments, the first forming assembly 27 and the second forming assembly 28 can be arranged in series one behind the other and configured to operate in direct temporal sequence to produce the finished component 10 in a single process.

[0115] In some embodiments, the first molding assembly 27 comprises a punch 29, a first molding die 30, and a first injection unit 31, the punch 29 and the first molding die 30 being adapted to cooperate to define a first molding volume V1 therebetween, and the first injection unit 31 being configured to inject a first plastic material into the first molding volume V1.

[0116] In some embodiments, the first molding volume V1 has a first maximum width W1 that corresponds to the first thickness S1 of the first layer 11. max It has.

[0117] In some embodiments, the first injection unit 31 comprises first heating means 53 configured to heat the first plastic material to a first injection temperature T1.

[0118] In some embodiments, punch 29 has a contrast surface 32 configured to be the negative of the shape of inner surface 13 of first layer 11 of member 10 .

[0119] In some embodiments, the contrast surface 32 may be substantially uniform and smooth.

[0120] For example, if the component 10 is suitable for producing a kettle 50A, the punch 29 may be substantially frusto-conical, and if the component 10 is suitable for producing a toaster 50B, the punch 29 may be parallelepiped-shaped with a rectangular cross section.

[0121] The first receiving mold 30 has a first molding surface 33 that is a negative mold of the shape of the second surface 14 of the first layer 11 .

[0122] In some embodiments, the first molding die 30 may have one or more first molding sides 37 that are configured to be positioned adjacent to each other in use to form one first molding surface 33 of the first molding die 30.

[0123] In some embodiments, at least a portion of the first moulding surface 33 has a first moulding ridge 38 that, in use, projects into the first moulding volume V1.

[0124] The first molding ridge 38 is a negative of the shape of the fill cavity 19 that will be formed in the first layer 11 .

[0125] In some embodiments, the second molding assembly 28 includes a second molding die 34 having a second molding surface 35 adapted to form a negative of the shape of the outer surface 15 of the member 10.

[0126] The second forming mold 34 is suitable for cooperating with the second surface 14 of the first layer of material 11 in use to define a second forming volume V2 between the second forming mold 34 and the second surface 14.

[0127] In some embodiments, the second molding volume V1 has a second width W2 that corresponds to a second thickness S2 of the second layer 12. max and a second width W2 max is the first width W1 max Greater than.

[0128] In some embodiments, the second width W2 max and the first width W1 max The ratio is 1.05 to 2.5, preferably 1.1 to 2.

[0129] The second mold assembly 28 further includes a second injection unit 36 ​​configured to inject a second plastic material into the second mold volume V2.

[0130] In some embodiments, the second injection unit 36 ​​comprises second heating means 54 configured to heat the second plastic material to a second injection temperature T2.

[0131] In some embodiments, the first heating means 53 and the second heating means 54 can be operated and regulated independently of each other.

[0132] In some embodiments, the second mold die 34 includes one or more second mold sides 39 .

[0133] In particular, the second forming sides 39 are configured to be positioned adjacent to each other in use to form the second forming surface 35 of one of the second forming molds 34 .

[0134] In other embodiments, the first forming assembly 27 has at least one coupling protrusion 41 that forms an opening 21 or slot or exposed portion S in the first layer 11 that is free of the first material while simultaneously maintaining the punch 29 and the first receiving die 30 separated from each other.

[0135] In some embodiments, at least one coupling protrusion 41 is provided on one of the first molded sides 37 .

[0136] In particular, the coupling protrusion 41 is configured to cooperate with the punch 29 to confine and restrict a portion of the first molding volume V1 and prevent the first material from entering this location, thereby creating an exposed portion S, i.e., a substantial void portion, in the first layer 11.

[0137] In some embodiments, the bonding protrusions 41 are formed to minimize bonding contact with the punch 29 in order to preserve the finish and gloss of the contrasting surface 32 of the punch 29 corresponding to the one or more exposed sites S.

[0138] In some embodiments, such as those described with reference to Figure 8, the coupling protrusion 41 has at least one protrusion abutment 42 that is suitable for being positioned in contact with the contrast surface 32 of the punch 29 to form an empty space or cavity 43 between the punch 29 and the corresponding first molding surface 33.

[0139] In another embodiment, the coupling protrusion 41 may be provided on the punch 29, and in that case, a cavity 43 may be formed between the punch 29 and the first receiving die 30 of the punch 29, more specifically along the contrast surface 32.

[0140] In some embodiments, such as those described with reference to Figure 10, the coupling protrusion 41 may have a pair of abutment portions 42 or one annular abutment portion suitable for isolating and defining the cavity 43 from the first molding volume V1.

[0141] The abutment portion 42 is configured to bear against the surface 32 of the punch 29 in use to ensure an airtight seal of the cavity 43 .

[0142] In this way, the first molding volume V1 is limited at the corresponding exposed portions S of the first layer 11 where the openings 21 are provided.

[0143] In some embodiments, the cavity 43 has a height defined as the distance between the opposing surfaces of the punch 29 and the first receiving die 30, and the height is from several tens of micrometers to several hundreds of micrometers.

[0144] In some embodiments, the width of the abutting portion 42 is several hundred micrometers, for example, 0.2 to 1.5 mm.

[0145] This width is approximately the same as the overall width of the portion that contacts either the contrast surface 32 or the first molding surface 33, and this overall width is measured based on the side that will become the edge of the exposed portion S when in use.

[0146] A value in the range of 0.2 to 0.9 mm can minimize contact between the punch 29 and the receiving die 30 and obtain a cavity 43 with a larger area.

[0147] A slightly larger width, for example 0.9 to 1.5 mm, has the disadvantage of slightly reducing the area of ​​the cavity 43, but this is the only drawback, and it allows an airtight seal between the punch 29 and the receiving die 30 to be guaranteed even when the closing force is relatively small or when the required processing accuracy is low.

[0148] In some embodiments, one or more coupling protrusions 41 may be provided depending on the shape and size of the exposed portion S or opening 21 to be formed, and if there are multiple coupling protrusions 41, they may have the same or different shapes.

[0149] For example, in the case of the component 10 applied to the kettle 50A, a first connecting protrusion 41A (FIG. 10) suitable for forming a window 22 for checking the water level, a second connecting protrusion 41B for forming a transparent peripheral strip 25 (FIG. 10), and a third connecting protrusion 41 for forming a spout 51 can be provided.

[0150] In some embodiments, the abutment 42 may be shaped to correspond to the shape of the exposed portion S that is to be formed in the member 10 .

[0151] For example, the abutment portion 42 can have a closed-shaped transition that runs along the vertical portion of the first receiving mold 30, the closed-shaped transition having a circular profile or having straight and curved sections, the closed-shaped transition being suitable for defining the exposed area S corresponding to the sidewall of the first layer 11 of the member 10.

[0152] In other embodiments, the abutment 42 may be shaped to conform to the edge 24 of the first layer 11 .

[0153] In the above solution, the abutment portion 42 has an annular shape and can move in a direction perpendicular to the axis X so as to contact the punch 29 along the periphery or circumference of the punch 29 and limit the lower part of the first forming volume V1.

[0154] The cavity 43 between the punch 29 and the first forming die 30 advantageously preserves the finish and gloss of the contrasting surface 32 of the punch 29, even after several forming cycles.

[0155] In some embodiments, at least a portion of the second molding surface 35 is formed with a plurality of cavities 40a alternating with each molding relief 40b.

[0156] In particular, the cavity 40 a and the molded relief 40 b are adapted to be the negative of the shape of the aesthetic relief 16 provided on the outer surface 15 .

[0157] Thus, the shape and size of the cavities 40 a and the molded reliefs 40 b correspond to the shape and final size of the protrusions 17 and recesses 18 on the outer surface 15 .

[0158] The cavity 40 a and molding relief 40 b correspond to the molding ridge 38 of the first molding die 30 .

[0159] In other words, the shape, size and location of the cavities 40 a and molding reliefs 40 b of the second molding die 34 match the shape, size and location of the molding ridges 38 of the first molding die 30 .

[0160] In particular, the shaped relief 40b is located in a position that corresponds to the position of the shaped ridge 38 in use.

[0161] In some embodiments, the first molded side 37 and the second molded side 39 are interchangeable so that members 10 having different aesthetic shapes can be produced with the same apparatus 26 .

[0162] For example, multiple sets of first molded sides 37 and second molded sides 39 may be provided, each having a different surface finish, depending on the final appearance desired for the component 10.

[0163] In some embodiments, the first injection unit 31 and the second injection unit 36 ​​each have at least one injection device 44 and at least one injection passage 45, and the injection passage 45 can fluidly connect each injection device 44 to either the first injection volume V1 or the second injection volume V2.

[0164] In some embodiments, multiple injection devices 44 may be provided for each injection unit 31,36.

[0165] In some embodiments, at least one injection passage 45 is formed in at least one of the first mold sides 37 and at least one of the second mold sides 39 .

[0166] In some embodiments, the apparatus 26 may include a first cooling circuit 46 and a second cooling circuit 47 for each molding assembly 27, 28, respectively.

[0167] In some embodiments, the first cooling circuit 46 and the second cooling circuit 47 are independent of each other and are configured to cool the first layer 11 and the second layer 12 to different corresponding cooling temperatures T3, T4, respectively.

[0168] In some embodiments, the first cooling circuit 46 is configured to cool the first layer 11 to a first cooling temperature T3, and the second cooling circuit 47 is configured to cool the second layer 12 to a second cooling temperature T4 that is lower than the first cooling temperature T3.

[0169] The first cooling circuit 46 comprises one or more cooling passages 48 of known type, not shown in the drawings, and a unit for pumping the coolant or a heat exchanger with a cooling circuit.

[0170] The second cooling circuit 47 comprises one or more cooling passages 49 of known type not shown in the drawings and a unit for pumping the coolant or a heat exchanger with a cooling circuit.

[0171] In some embodiments, the cooling passages 48 , 49 may be formed through at least one of the first forming side 37 and / or the second forming side 39 and / or the punch 29 .

[0172] In particular, the cooling passages 48, 49 are configured to carry a coolant such as water, emulsion and / or oil.

[0173] The embodiments now described with reference to FIGS. 5 to 12 also relate to a method for manufacturing a component 10 provided with at least one transparent region T.

[0174] The method comprises a first step of injecting an opaque first plastic material to create a first layer 11, and a second injection step of injecting a transparent second plastic material to create a second layer 12.

[0175] In some embodiments, the method includes restricting at least a portion of the first molding volume V1 in a first injection step to form at least one exposed area S in the inner first layer 11, and injecting a second material into the second molding volume V2 in a second injection step to cover the entire first layer 11 and the at least one exposed area S of the first layer 11, thereby obtaining a transparent area T.

[0176] For example, the method may involve forming an opening 21 or slot in the first layer 11 to create a window 22 and covering the opening 21 or slot with a second material.

[0177] In some embodiments, the method produces an inner first layer 11 with a first thickness S1 and an outer second layer 12 with a second thickness S2 that is greater than the first thickness S1.

[0178] In some embodiments, the method includes ejecting a first material at first operating parameters and ejecting a second material at second operating parameters that are different from the first operating parameters.

[0179] In some embodiments, by fabricating the second layer 12 at a different, larger thickness relative to the first layer 11, lower temperature and pressure processing parameters can be used, which can improve surface stability and brightness, i.e., reduce distortion that may occur during the post-shrinkage step.

[0180] In some embodiments, the method includes positioning a punch 29 and a first forming die 30 relative to each other to define a first forming volume V1 therebetween, and injecting a first material into the first volume V1 thus defined. The first forming volume V1 is defined between a contrast surface 32 and a first forming surface 33 of the punch 29, as shown on the right hand side of FIG. 5 and in FIG. 9.

[0181] In some embodiments, the method injects the first material at defined temperature and pressure parameters.

[0182] In some embodiments, the method injects the first material at a first temperature T1 between 150°C and 260°C (at least for propylene).

[0183] In another embodiment, the first temperature T1 is in the range of 120°C to 240°C, preferably 160°C to 220°C, and more preferably 180°C to 200°C.

[0184] In one embodiment, the method comprises: 2 ~1300kg / cm 2 The first material is injected at a first pressure P1.

[0185] In another embodiment, the first pressure P1 is 750 kg / cm 2 ~1250kg / cm 2 , more preferably 800 kg / cm 2~1200kg / cm 2 It can be said that:

[0186] The first injection step makes it possible to obtain the first layer 11 of the component 10 (FIGS. 6 and 10).

[0187] In some embodiments, the method can include cooling the first layer 11 to a first cooling temperature T3 in the first injection step.

[0188] In some embodiments, the method may include circulating a refrigerant in a first cooling circuit 46 to cool at least one of the first receiving mold 30 and / or punch 29 to cool the first layer 11.

[0189] In some embodiments, the method uses a first cooling temperature T3 in the range of 35°C to 55°C, more preferably 40°C to 50°C.

[0190] The method then places the punch 29 with the first layer 11 formed on the surface of the punch 29 into the second forming assembly 28, where the second receiving die 34 is positioned to mate with the second surface 14 of the first layer 11 to define a second forming volume V2.

[0191] A second moulding volume V2 is defined between the second surface 14 of the first layer 11 having the fill cavity 19 and the second moulding surface 35, as shown, for example, on the right hand side of FIG. 7 and in FIG.

[0192] Thereafter, the method comprises a second injection step of injecting a second plastic material into a second mould volume V2 at a second injection temperature T2 and a second injection pressure P2.

[0193] In one possible embodiment, the second injection step immediately follows the first injection step.

[0194] In one embodiment, the method uses a second temperature T2 that is lower than the first injection temperature T1.

[0195] In a preferred embodiment, the second injection temperature T2 is in the range of 0.90 to 0.95 times the first injection temperature T1. In other words, the second injection temperature T2 is 5 to 10% lower than the first injection temperature T1.

[0196] In one embodiment, the second pressure P2 may advantageously be lower than the first pressure P1.

[0197] In one embodiment, the second injection pressure P2 may be in the range of 0.70 to 0.90 times the first pressure P1, in other words, the second pressure P2 is 10 to 30% lower than the first pressure P1.

[0198] The second injection step creates the outer second layer 12 of the component 10 .

[0199] In some embodiments, the method can include cooling the second layer 12 to a second cooling temperature T4 in a second injection step.

[0200] In some embodiments, the method may include circulating a refrigerant in a second cooling circuit 47 to cool at least one of the second receiving mold 34 and / or punch 29 to a second cooling temperature T4 to cool the second layer 12.

[0201] In some embodiments, the second cooling temperature T3 may be 15% to 25% lower than the first cooling temperature T4.

[0202] In a preferred embodiment, the second cooling temperature T4 may be in the range of 25°C to 45°C, more preferably 30°C to 40°C.

[0203] In another embodiment, the method produces an outer second layer 12 having a three-dimensional finish on its outer surface 15 with alternating peaks 17 and valleys 18 .

[0204] In some embodiments, the method separates the forming punch 29 from the second forming die 35 at the end of the second injection step to remove the part 10 .

[0205] <Example> The applicant has conducted experimental tests and demonstrated that it is possible to vary the injection temperatures T1, T2 and cooling temperatures T3, T4 as well as the injection pressures P1 and P2 within the ranges under consideration depending on the difference between the thickness S1 of the first layer 11 and the thickness S2 of the second layer 12.

[0206] Table 1 below shows possible ratios of processing temperatures and pressures that can be used in the first and second injection steps, corresponding to the ratio of thicknesses S1, S2. [Table 1]

[0207] It will be apparent that modifications and / or additions to individual portions or steps may be made to the component 10, the apparatus 26 and the method described above without departing from the field and scope of the present invention.

[0208] Furthermore, although the present invention has been described with reference to some specific examples, it is clear that those skilled in the art will certainly be able to achieve many other equivalents of the component 10, device 26 and method having the features set forth in the claims, and all such equivalents fall within the scope of protection set forth in the claims.

Claims

1. 1. An apparatus (26) for manufacturing a component (10) made of a plastic material suitable for forming a housing for a household appliance (50) such as a kettle (50A) or a toaster (50B), the component (10) having at least one transparent area (T), a first molding assembly (27) including a punch (29), a first receiving die (30) and a first injection unit (31); and a second molding assembly (28) including a second receiving die (34) and a second injection unit (36); The punch (29) has a contrast surface (32), the first receiving die (30) has a first forming surface (33) adapted to define a first forming volume (V1) between the punch (29) and the first receiving die (30); the first injection unit (31) is configured to inject an opaque first plastic material into the first mould volume (V1) to create an inner first layer (11); the second receiving die (34) has a second molding surface (35) adapted to mate with the first layer (11) of the member (10) and the punch (29) to define a second molding volume (V2); the second injection unit (36) is configured to inject a transparent second plastic material into the second mould volume (V2) to create a second layer (12) such that the second layer (12) completely covers the first layer (11); At least one of the punch (29) or the first receiving die (30) has at least one coupling protrusion (41) that limits at least a portion of the first molding volume (V1) so as to form at least one exposed area (S) in the first layer (11); said second molded volume (V2) extending within said at least one exposed area (S) of said first layer (11); The at least one coupling protrusion (41) has a protruding abutment portion (42), The abutment portion (42) contacts either the contrast surface (32) of the punch (29) or the first molding surface (33) of the first receiving die (30) in use to limit the first molding volume (V1) and form an empty space or cavity (43) between the punch (29) and the first receiving die (30) corresponding to the exposed region (S). An apparatus (26) characterized in that

2. the outer second layer (12) fills the entire at least one exposed area (S) of the inner first layer (11) and is continuous with the first plastic material to form part of the inner surface (13) of the component; 10. The apparatus of claim 1.

3. The width of the portion of the abutment portion (42) that comes into contact with the contrast surface (32) or the first molding surface (33) is 0.2 to 1.5 mm.

3. The apparatus of claim 2.

4. The abutment portion (42) has a width of 0.9 to 1.5 mm.

4. The apparatus of claim 3.

5. The abutment (42) has a closed transition, the closed-shaped transition has a circular profile or has straight and curved sections; the transition of the closed shape is suitable for defining an exposed area (S) corresponding to a sidewall of the first layer (11) of the component (10); 5. An apparatus according to any one of claims 1 to 4.

6. the abutment (42) has a closed transition with an annular profile, the transition of said closed shape is transverse to the vertical axis (X) so as to contact the punch (29) along the periphery thereof and limit the lower part of said first forming volume (V1); 6. An apparatus according to any one of claims 1 to 5.

7. A method for manufacturing a component (10) made of a plastic material suitable for forming a housing for a household appliance (50) such as a kettle (50A) or a toaster (50B), the component (10) having at least one transparent area (T), comprising: a first injection step in which an opaque first plastic material is injected into a first molding volume (V1) defined between a punch (29) and a first receiving die (30) having a first molding surface (33) to create an inner first layer (11), and the first molding volume (V1) is restricted at least in part to form an exposed area (S) in the first layer (11); a second injection step of injecting an at least partially transparent second plastic material into a second molding volume (V2) defined between the first layer (11) obtained in the first injection step, the punch (29), and a second receiving mold (34) to create a second layer (12) covering the entire first layer (11) and to cover the exposed region (S) with the second plastic material to create a transparent region (T) in the component (10); and At least one of the punch (29) or the first receiving die (30) has at least one coupling protrusion (41) that limits at least a portion of the first molding volume (V1) to form the exposed area (S) in the first layer (11); During the first injection step, at least one protruding abutment portion (42) of a coupling protrusion (41) of the first receiving die (30) or the punch (29) is positioned to contact at least one of the contrast surface (32) of the punch (29) or the first molding surface (33) of the first receiving die (30), thereby limiting the first molding volume (V1) and forming an empty space or cavity (43) between the punch (29) and the first molding surface (33) corresponding to the exposed area (S).

8. the outer second layer (12) fills the entire at least one exposed area (S) of the inner first layer (11) and is continuous with the first plastic material to form part of the inner surface (13) of the component; The method of claim 7.

9. The abutment portion (42) and the contrast surface (32) are positioned so that they come into contact with each other only over a width of 0.2 to 1.5 mm.

9. The method according to claim 7 or 8.

10. The second injection step is performed immediately after the first injection step.

10. The method according to any one of claims 7 to 9.

11. A household appliance such as a kettle (50A) or a toaster (50B), The device comprises a container made of a plastic material member (10), The member (10) is an inner first layer (11) made of an opaque first plastic material; an outer second layer (12) made of a transparent second plastic material that covers the entire inner first layer (11); It is equipped with Furthermore, there is provided at least one transparent area (T) made integrally with said element, said transparent area (T) being defined by the transparent second plastic material making up said second layer (12), the transparent region (T) extends into and / or above at least one exposed region (S) of the first layer (11); The outer second layer (12) fills the entire at least one exposed area (S) of the inner first layer (11) and is continuous with the opaque first plastic material to form part of the inner surface (13) of the component. A household appliance characterized by:

12. at least one of a window (22) or a peripheral strip (25) consisting of said at least one transparent area (T), Domestic appliance according to claim 11.

13. The household appliance is a kettle (50A) and has a spout (51) consisting of the at least one transparent area (T).

13. A household appliance according to claim 11 or 12.

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