FR2967507A1 - METHOD FOR MANUFACTURING MULTI-COMPONENT MIRROR DEVICE AND DEVICE OBTAINED - Google Patents

Abstract

A method of manufacturing a light reflecting device (1) formed of at least two components (2, 3) connected to each other. The first component (2) is of a very mechanically strong material and the second component (3) is of a material having a light reflective coating. The two components (2, 3) are produced by a multicomponent injection process and are thus interconnected. The first component (2) comprises at least one clearance (5) and / or at least one undercut part (6) in which at least part of the second component (3) penetrates.

Description

FIELD OF THE INVENTION The invention relates to a method of manufacturing a light-reflecting device, in which at least two components are assembled, at least one first component being made of a mechanically very strong material and at least one second component being of a material capable of being coated with a light reflecting coating. The invention also relates to a light reflecting device consisting of at least a mechanically very strong first component and at least a second component coated with a light reflective coating. STATE OF THE ART It is usual and known in the state of the art to connect a reflecting mirror to a fixing frame by means of a snap-on or glued connection. The various components are usually manufactured separately by injection or by injection printing and they are assembled together in a subsequent step. For the corresponding elements, it is necessary each time an injection tool and an injection machine. To have a variant, it is necessary to manufacture a new injection mold 20 for the mirror and the frame, which is expensive. The reflective mirror attachment frame is usually made of a reinforced thermoplastic material (for example with glass fibers and / or minerals). The mirror is then attached to the mounting frame and mounted to allow position adjustments. The stresses exerted during the use of such a mirror, for example under the effect of vibrations during the operation of a vehicle, and the thermal stresses require thermoplastics having high mechanical characteristics. Since the reinforcing materials used to increase these characteristics reduce the optical quality required, in the manufacture of such mirrors, the unreinforced thermoplastic material is first injected, which also has the advantage of being easily equipped with coating. The fastening frame is separately injected with the reinforced thermoplastic material and then joined with the unreinforced mirror element provided with the coating.

EP-A-0 636 907 discloses, for example, a process for producing reflective devices in which a charge reinforced plastic is molded according to an injection method and then provided with a reflective coating.

OBJECT OF THE INVENTION The object of the present invention is to develop a process for producing a light reflecting device that does not require additional assembly steps for assembling the various components.

DESCRIPTION AND ADVANTAGES OF THE INVENTION For this purpose, the object of the invention is a process of the type defined above, characterized in that the two components are produced by a multicomponent injection process and are thus interconnected.

The method thus avoids the additional assembly steps to assemble the different components. At the same time, it suffices for a single injection mold and a single injection machine to apply the invention. One of the components is the first reinforced component, which is the basic support for many variants of different reflector system models. The second component constitutes the second unreinforced component which has an optimum outer surface and can thus be well coated. Since the at least two components of the reflective device are made completely in one injection cycle, these different components do not have to be made by different injection tools on other injection machines. In contrast, the device can be manufactured in a two-component injection mold and a two-component injection machine with a turntable. This saves not only energy and material, but also time for assembling the various components. According to a particularly advantageous development, the first component is firstly injected, this first component having at least one clearance and / or at least one part against undercut and then the second component, the release (s) and / or the undercuts (s) of the solid material being then filled at least

3 in part with the coating material. In this way, a very solid connection is made between the components since the two components are practically assembled by toothing due to the penetration of the second component into the clearance (s) and / or the counterweight (s). of the first component. As the different components are connected to each other during the multicomponent injection process, no additional means are needed to connect them together. If the second component is printed on the first component by a printing and injection punch, the connection between these components is additionally fixed. According to a preferred development of the process, the first material of the first component is injected first into at least one cavity of the injection mold. After cooling of this first component, it is placed in at least a second cavity of the injection mold, preferably by means of a turntable. The coating material of the second component is then injected into at least a second cavity of the injection mold. Preferably, the second component may be printed on the first component by an injection printing punch. Then, the finished device is demolded, preferably by ejecting it with the injection printing punch. This process allows very efficient and economical manufacturing of reflective devices in a single step. The second component is preferably provided with a light reflective coating. This coating may for example be carried out by evaporation under vacuum, spraying, spray coating or by a similar method. As a coating material, it is possible, for example, to use aluminum. According to a particularly advantageous development of the invention, the reflective coating is applied before the injection of the second component onto at least one surface of the corresponding cavities of the injection tool. Then, the coating material is sprayed onto the coating. The reflective coating is advantageously molded onto the base body of the second component during filling of the injection mold. For this, before filling the injection mold 4 with the material of the base body, the coating material is applied to a surface of the injection tool. This avoids a subsequent coating, including the intermediate steps that would be necessary. In addition, the process according to the invention makes it possible to use a large number of materials, for example filled or ex-dressed materials, which, because of surface defects associated with the conventional coating process, can not be used. coated. In addition, incorporating shaping and coating significantly reduces labor costs and investment. The subject of the invention is also a device of the type defined above, characterized in that the first component comprises at least one cavity and / or at least one undercut part in which this second component penetrates at least in part. A very solid connection is thus made between the components because the two components are practically connected by a toothing thanks to the interpenetration of the second component in the cavity (s) and / or the undercut (FIG. s) of the first component. Additional connecting elements or additional means for fixing the connection or stabilizing the entire device are thus not necessary, which simplifies the manufacturing process of the device according to the invention and makes it more economical. The first component is preferably at least partly made of a very strong plastics material, for example polyphenylene sulfide (PPS) and / or polybutylene terephthalate (PBT), both of which ensure high strength of the device when used. alone or in combination. In particular, the material of the first component must be an injectable thermoplastic polymer and which is characterized by a very high strength and rigidity, a high temperature resistance as well as good friction and wear properties. To further increase the strength, the material of the first component can be reinforced with glass fibers and / or minerals. The second component is preferably at least partly made of a transparent plastics material, for example polycarbonate (PC), polymethyl methacrylate (PMMA), a copolymer (COC) or a polymer (COP) synthesized from polyolefins. so that this component is transparent to light and has a surface that can be coated easily and without inconvenience. Thanks to the treatment with the multicomponent injection process, the transparent plastic material must also be a thermoplastic polymer, which can be injected. Drawings The present invention will be described hereinafter in more detail with the aid of an example of a method for manufacturing a light-reflecting device and a device of the same, shown in the accompanying drawings in which: FIG. 1 is a schematic perspective view of a device according to the invention; FIG. 2 is a section of the device of FIG.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 shows a device 1 according to the invention comprising a mechanically very strong first component 2 and a second component 3. The second component 3 is provided with a reflective coating 4 on its surface. not facing the first component 2.

The coating 4 is, for example, aluminum deposited with steam. While the second component 3 functions as a mirror surface, the first component 2 serves as a support which gives the device 1 the required strength and also allows a solid attachment of the device 1, for example in a housing.

FIG. 2 clearly shows that the first component 2 has recesses 5 into which the material of the second component 3 penetrates so as to have a very solid connection between the two components 2, 3. The recesses 5 have undercuts 6 which reinforce more the attachment of the second component 3 in the first component 2. The device 1 according to the invention can be for example obtained by a two-component injection machine equipped with a turntable and applying an injection mounting method . In a first step, the reinforced thermoplastic component is injected and then cooled to produce the first component 2 by means of an injection cylinder in an injection mold. This first thermoplastic component is for example a polyphenylene sulphide (PPS) with glass fibers and minerals or a polybutylene terephthalate (PBT) with glass fibers which have a high mechanical and thermal strength but are difficult to coat. In a second step, the injection tool is opened and one side of the tool is rotated with the turntable so as to place the first component 2 in the second cavity. In the third step, the unreinforced thermoplastic component is injected to make the second component 3 using an injection cylinder in the second cavity. The plastic material also flows into the recesses 5 of the first component 2 and is attached to it, in particular also thanks to the undercuts 6. This second thermoplastic component can be, for example, an unreinforced polycarbonate (PC), a copolymer (COC) or a polymer (COP) 1s synthesized from cycloolefins, which are easily coated with a coating but have reduced thermal and mechanical stability. The second cavity may be equipped with an injection printing punch which enables the second thermoplastic component to be printed without delay and without sagging against the first component 2. After cooling the plastic material, this punch constitutes the ejector contour and expels the entire device 1 of the cavity. The injection punch can be simply replaced in the tool for another variant of mirror shape. Since it is difficult to have the mechanical strength and the respect of the optical requirements with only one type of plastic material, the process according to the invention preferably uses at least two different thermoplastic materials to meet the different requirements of injection technique. . At the same time, for fixing (first component 2), it will always be possible to use a base body on which the respective mirror variant (second component 3) is overmolded by injection. This saves time and reduces costs for the various fasteners / injection molds. If an expensive plastic optical material is used, there will also be a saving through the use of a more advantageous carrier material. As the connections between the various components 2, 3 are firmly enclosed and are neither glued nor clipped, the device according to the invention has a very high strength and resistance, which is reflected in a positive way, especially for parts used for a long time. The device 1 according to the invention can be applied in principle to all mirror systems which must be placed and fixed in a housing. Due to the very great strength of the device according to the invention 1 and the relatively advantageous manufacturing costs, it is advantageous to apply the invention to mirror systems equipping the vehicles. io

Claims (1)

CLAIMS1 »A method of manufacturing a light reflecting device, in which at least two components are assembled, at least one first component being made of a very strong mechanical material and at least one second component being of a material capable of to be coated with a coating reflecting light, characterized in that the two components (2, 3) are made by a multicomponent injection method and are thus interconnected. 2 »Process according to claim 1, characterized in that the first component (2) is first injected, the first component (2) having at least one clearance (5) and / or at least one part thereof. against undercut (6) and then the second component (3) is injected, * the clearance (5) and / or against the undercut (6) of the solid material being filled at least partially with the coating material. 3. The process according to claim 2, characterized in that the second component (3) is printed on the first component (2) by an injection printing punch. 4 »Process according to claim 1, characterized by the following steps: a) injecting the high mechanical stability material for the first component (2) into at least a first cavity of an injection tool, b) cooling the first component (2), c) placing the first component (2) in at least a second cavity of the injection tool, preferably with a turntable, 2967507 d) injecting the coating material of the second component (3) in at least a second cavity of the injection tool, and e) preferably printing the second component (3) on the first component (2) with a printing punch, and sf) demolding the finished device (1) preferably by ejection using an injection printing punch. 5. The process as claimed in claim 1, characterized in that the second component (3) is coated with a coating (4) reflecting light. 6. The process as claimed in claim 5, characterized in that the light-reflecting coating (4) is applied before the injection of the second component (3) onto at least one surface of the corresponding cavity of the injection tool. and then the coating material is projected onto the coating (4). 7. A light-reflecting device (1) consisting of at least one mechanically very strong first component and at least one second component coated with a light reflecting coating, characterized in that the first component (2) comprises at least one cavity (5) and / or at least one undercut part (6) in which the second component (3) penetrates at least partially. 8 »Device according to claim 7, characterized in that the first component (2) is at least partly made of a very strong plastics material, preferably polyphenylene sulfide (PPS) and / or polybutyleneterephthalate (PBT). 9. The device according to claim 8, characterized in that the material of the first component (2) is reinforced with glass fibers and / or minerals. 10 »Device according to claim 7, characterized in that the second component (3) is at least partly made of a transparent material, preferably polycarbonate (PC), polymethylmethacrylate (PMMA), and / or a copolymer ( COC) and / or polymer (COP) synthesized from cycloolefins. io