EP1059368A2 - Process for metallising of moulded parts and for the manufacture of a sealed enclosure - Google Patents

Abstract

Process for metallizing molded parts comprises galvanizing an electrically conducting functional intermediate layer having low transition resistance, and galvanizing a decorative layer. During galvanizing of the decorative layer, a region (118, 120) of a counter element lies over a region (100, 102) of the molded part (38) so that the galvanic application in this region is reduced.

Description

a) galvanisches Aufbringen mindestens einer elektrisch leitenden, funktionellen Zwischenschicht mit niedrigem Übergangswiderstand;

b) galvanisches Aufbringen einer dekorativen Schicht.

The present invention relates to a method for metallizing molded parts, which comprises the following steps:

a) galvanic application of at least one electrically conductive, functional intermediate layer with low contact resistance;

b) galvanic application of a decorative layer.

The process mentioned at the beginning is for metallization widely used in molded parts and known from the market. Galvanic, i.e. metallic, decorative coatings from Shaped parts are therefore particularly preferred nowadays, because they are insensitive to environmental influences, scratch-resistant and are visually appealing. With different Procedures are also different coloring of the galvanic decorative layer possible, according to the respective purpose. As a "base" for the im general exterior galvanic decorative layer usually serves an electrically conductive functional Interlayer made of a material on which the decorative Layer separates optimally during electrolysis. Typical molded parts, which with such a decorative Layer are coated, for. B. the housing shells of mobile phones.

For various reasons it may be necessary that the molded parts each with a different element electrically be conductively connected. For example, the housing of Mobile phones usually consist of two half-shells built up, which are put together. To an education and Entry of electromagnetic radiation from a such housing out or into such a housing to avoid at the junction, there will be a electromagnetic seal applied, which with both Housing half shells works together. It can be e.g. around a seal with an electrically conductive Act components enriched elastic material, which is applied to the connection points.

However, it has now been found that the previous electrical no conductive connection at the connection points is optimal.

The present invention therefore has the task of beginning further mentioned methods so that one with receives a molded part that is electrically good conductive can be connected to another element.

c) während des galvanischen Aufbringens der dekorativen Schicht ein Bereich des Formteiles einem Bereich eines Gegenelementes in so geringem Abstand gegenüberliegt, daß der galvanische Auftrag der dekorativen Schicht in diesem Bereich reduziert ist.

This object is achieved in that

c) during the galvanic application of the decorative layer, an area of the molded part is so close to an area of a counter element that the galvanic application of the decorative layer is reduced in this area.

c) während des galvanischen Aufbringens der dekorativen Schicht an einem Bereich des Formteiles ein Bereich eines Gegenelementes so anliegt, daß der galvanische Auftrag der dekorativen Schicht in diesem Bereich reduziert ist.

Alternatively, the solution is that

c) during the galvanic application of the decorative layer on a region of the molded part, a region of a counter element rests in such a way that the galvanic application of the decorative layer is reduced in this region.

The solutions according to the invention were based on the knowledge that that despite the good conductivity of some decorative Layers whose contact resistance to another conductive material such as B. an electromagnetic Seal, is relatively high (in the range of a few thousand Milliohms). In a next step it was recognized that the contact resistance of a usual electrical conductive functional interlayer to another electrically conductive material is significantly lower and is only in the range of a few milliohms. It seemed thus favorable when metallizing the molded part Generate area where the decorative layer is either completely interrupted or their thickness at least strongly is reduced.

To solve this problem was on a property certain used to form decorative layers Used materials that are otherwise rather than is perceived as disturbing: the bad so-called "encroachment" in galvanic deposition. Below that is the Understand the property of these materials Electroplating in poorly accessible places, e.g. in narrow holes etc., or on completely covered ones Places worse than in freely accessible places or not to be reflected there at all. Now how is provided according to the invention during the galvanic Applying the decorative layer to an area of the molded part an area of a counter element in very little Spaced opposite or adjacent to this, takes place in this area due to the bad Encompasses the galvanization with the decorative layer not or only significantly in relation to the other area reduced way.

This is after metallizing the molded part the decorative layer either not at all present or at least greatly reduced in thickness. So the usual electrical is at this point conductive and functional intermediate layer free which a much lower contact resistance to others provides conductive materials.

Advantageous developments of the invention are in the subclaims specified.

A typical example of a material that the bad wrap is chrome. According to claim 3 are therefore chrome-containing decorative Layers particularly preferred.

The inventive method works particularly economically according to claim 4, if it is the counter element is also a molded part.

According to claim 5, it is the opposite Areas around complementary shaped Areas. This makes it possible during plating a constant small distance between ensure the areas and thus a uniform reduced galvanization due to the decorative layer to achieve in this area.

The further development according to claim is particularly preferred 6, after which the intermediate layer comprises nickel. Nickel the advantage that decorative galvanic layers very can be electroplated well. On the other hand, the Contact resistance of nickel to other materials relatively low and the corrosion and oxidation resistance quite high.

Molded parts are being used more and more often today, which, as stated in claim 7, are made of plastic.

a) chemisches Aufbringen einer ersten metallischen, vorzugsweise kupferhaltigen Basisschicht; und

b) galvanisches Aufbringen einer zweiten metallischen, vorzugsweise kupferhaltigen Basisschicht.

In the case of such molded plastic parts, however, the method must include the following steps before applying the intermediate layer:

a) chemical application of a first metallic, preferably copper-containing base layer; and

b) galvanic application of a second metallic, preferably copper-containing base layer.

This procedure is necessary to make the electrical to create a conductive basis on these molded parts, which for electroplating to produce the functional Intermediate layer and the decorative layer is necessary.

According to claim 9, however, it can also be advantageous if the molded parts are made of metal, preferably magnesium, are.

In claim 10 is a distance between the areas during the galvanic application of the decorative layer specified, which has proven itself in practice as optimal Has. It should be between 0 and 5 mm.

The method according to claim 11 is particularly suitable for complex molded parts, preferably for housing shells of mobile phones. A complex shape in the area the opposite areas deteriorated the wrap and thus improves the desired result.

According to claim 12, the distance between the areas varies during plating in that during the galvanic application of the intermediate layer is larger than during the application of the decorative Layer. This ensures that the intermediate layer in these areas to the extent necessary is deposited.

The present invention also relates to a method to produce a closed housing from at least two housing parts with one the gap between the Housing parts sealing electrically conductive seal, whereby the housing parts are galvanized.

This process should be improved so that the interior of the housing better than before against electromagnetic Radiation is shielded.

This is achieved according to the invention in that the galvanization the housing parts by a method according to a of claims 1 to 12, with the areas in which the deposition of the decorative layer is reduced is applied, the electrically conductive seal becomes.

A housing manufactured in this way has base sections on which the electrically conductive seal is arranged with very low contact resistance, which provides good shielding from electromagnetic Radiation is achieved.

Figur 1:

eine schematische Darstellung eines Ausschnittes aus einer Galvanisierungsanlage;

Figur 2:

einen schematisierten Detailausschnitt aus Figur 1;

Figur 3:

eine teilweise gebrochene Schnittansicht entlang der Linie III-III von Figur 2; und

Figur 4:

einen Schnitt durch einen Verbindungsbereich eines abgeschlossenen Gehäuses.

The invention will now be described in detail with reference to the accompanying drawings. In this show:

Figure 1:

a schematic representation of a section of a galvanizing system;

Figure 2:

a schematic detail of Figure 1;

Figure 3:

a partially broken sectional view taken along the line III-III of Figure 2; and

Figure 4:

a section through a connection area of a closed housing.

In Figure 1, an electroplating system is included provided with the reference number 10. This includes one continuously working conveyor 12, its exact funding principle not interested here. The electroplating plant 10 further includes two filled with an electrolyte Plunge pools 14 and 16. The elements to be electroplated are shown only schematically in Figure 1 and with the Reference number 18 provided. You just hang over one suspension 17 shown schematically on conveyor 12.

The conveyor 12 is designed so that the to be galvanized Elements by the movement of the conveyor 12 in the direction of arrow 20 first in the electrolyte Immerse completely in plunge pool 14. At the in this electrolyte contained is preferably a nickel-containing electrolyte 22, with which one functional intermediate layer is formed. Subsequently are the elements 18 to be electroplated from the nickel-containing Electrolyte 22 lifted out and in a Plunge pool 16 existing electrolyte 24 for production completely lowered with a decorative outer layer. The electrolyte 24 is in the present embodiment contains chrome. An intermediate rinsing bath is in the drawing omitted for reasons of clarity. After passing through the chromium-containing electrolyte 24 in Plunge pools 16 become the elements to be electroplated 18 lifted out of the chromium-containing electrolyte 24 again. Before and after the two plunge pools shown in Figure 1 14, 16 can further (not shown) plunge pools be arranged in which to be galvanized Elements chemically or galvanically coated or processed become.

Electrodes 26 and 28 are in the plunge pools 14 and 16, respectively arranged at which a positive voltage + U is present. The elements 18 to be electroplated are conventional via the suspension 17 and a not shown Sliding contact electrically connected to a contact rail 30, to which a negative voltage -U is present. On in this way the elements to be galvanized form one Cathode attached to the electrolyte 22 or 24, nickel or chrome deposits.

For a detailed explanation of the suspension 17 will now referred to Figures 2 and 3. The following as Components referred to as “struts” are shown in FIG Clarity due to schematic as simple lines shown.

The suspension 17 comprises two upper struts 32, 34 and a holding cage 36 which, via the holding struts 32, 34 connected to the conveyor. In the holding cage 36 are the elements 18 to be galvanized, namely two housing half-shells 38, 40 of a mobile phone, still closed descriptive way.

The holding cage 36 consists of two half elements 42 and 44. The left half element in FIGS. 2 and 3 is 42 constructed as follows: two parallel to each other and in 2 and 3 vertical longitudinal struts 46, 48 are through at their upper and lower ends connecting struts 50 running perpendicular to them or 52 firmly connected to each other, so that a rectangular Frame is formed. The distance between the longitudinal struts 46 and 48, that is the length of the connecting struts 50 and 52, corresponds exactly to the horizontal distance between two pairs of stepped bores in the housing half-shell 38, which not at all in Figure 2 and of which in Figure 3 only those lying in the plane of the longitudinal strut 46 Stepped bores with the reference numbers 54 and 56 are visible. On the stepped bores 54 and 56 continues discussed in more detail below.

On the longitudinal struts 46 and 48 are at a right angle overall four retaining pins formed, of which in the figures 2 and 3 only those with the reference numerals 58 and 60 are visible are. The distance between the upper and lower retaining pins 58 and 60 correspond exactly to the vertical distance between the stepped bores 54 and 56. The retaining pins 58 and 60 are facing away from the longitudinal belt 46 and 58, respectively End graduated so that each one Paragraph 62 or 64 and a nose 63 or 65 is formed.

At the upper and lower ends of the longitudinal struts 46 and 48 of the left half element 42 are at a right angle to the longitudinal struts 46 and 48 and to the connecting struts 50 and 52 to the other half element 44 pointing connecting webs 66 molded. In the respective longitudinal strut 46 and 48 facing away from the end face have the connecting webs 66 each have a blind hole 68.

The right half element 44 in FIG. 3 is to the left half element 42 analogue structure: It comprises two vertical Longitudinal struts 70, 72, which at their upper and lower Ends connected by connecting struts 74 and 76 are. On the longitudinal struts 70 and 72 are in the right Angle retaining pins 78, 80, 82 and 84 formed. This are at their end facing the housing half-shell 40 also graduated so that one paragraph 86 or 88 and noses 87, 89 are formed (the paragraphs and the lugs of the holding pins 82 and 84 are in FIG. 3 not visible). Are at their top and bottom ends molded onto the longitudinal struts 70, 72 connecting webs 90, which are perpendicular to the longitudinal struts 70, 72 and also are perpendicular to the connecting struts 74 and 76. On the end face of the connecting webs facing the half element 42 90, a pin 92 is formed in each case, whose diameter is such that it is in the blind hole 68 of the connecting web 66 of the left half element 42 is held releasably with effort.

The holding struts 32 and 34 are each on the connecting struts 50 or 74 molded; however, you can also use these be releasably connected. The elements of the holding cage 36 are made of an electrically conductive material, likewise the struts 32 and 34. The surface of the Elements of the holding cage 36 is non-conductive Plastic layer 94 covered, except for the noses 63, 65, 87 and 89.

The housing half-shell 38 on the left in FIG. 3 comprises one rectangular bottom 94 to which a circumferential and in Edge 96 running essentially perpendicular to the bottom 94 constant height is formed. The edge 96 has one circumferential area 98 with greater wall thickness, which is adjacent to the floor 94, and a circumferential area with a smaller wall thickness 100, which is the edge of the Edge 96 is adjacent. Between areas 98 and 100 is a step facing the inside of the half shell 38 102 formed (see Figure 3). To the bottom 94 are from a total of four extensions molded on, from those in Figure 3 only those lying in the cutting plane Extensions 104 and 106 are visible. In these are the step bores 54 and 56 already mentioned above available, which also penetrate the bottom 94 (cf. Figure 3). The level (without reference number) shows in Towards floor 94.

The housing half-shell 40 on the right in FIG. 3 is similar how the left housing half-shell 38 is constructed: it comprises a rectangular bottom 112, which is approximately the same Dimensions as the bottom 94 and to the one peripheral and vertical edge 114 constant Height is formed. The floor 112 is adjacent to it Area 116 of the edge 114 thicker than that of the bottom 112 facing away, that is adjacent to the edge of the edge 114 Area 118. There is therefore a space between these areas formed radially outward step 120, which complementary to level 102 of the left housing half-shell 38 is. At the bottom 112 are also extensions from the inside molded, of which in Figure 3 only in extensions 122 and 124 of the cutting plane are visible. Perpendicular to the floor 112 are through the Extensions 122, 124 through step bores 126, 128 introduced, whose steps point towards the floor 112.

The diameters of the tabs 63, 65, 87, 89 and the areas the stepped bores 108, 110, 126 and 128 with a smaller one Diameters are matched so that the Housing half-shells 38 and 40 on the lugs 63, 65, 87, 89 are releasably held with force. In the operating state are the steps (without reference number) of the step holes 108, 110, 126 and 128 at paragraphs 62, 64, 86 and 88 so that the housing half-shells 38 and 40 relative to the half-elements 42, 44 of the holding cage 36 are arranged at a defined distance. The half elements 42 and 44 are in turn due to each other Crosspieces 66 and 90 at a defined distance arranged so that overall the housing shells 38th and 40 a position to one another defined in the installed position exhibit. This is chosen so that the distance between the edge of the area 100 of the edge 96 of the left housing half-shell 38 a short distance from the opposite Step 120 of the edge 114 of the right housing half-shell 40 has. Also the end of area 118 of the edge 114 of the right housing half-shell 40 lies in short distance from the level 102 of the left housing half-shell 38. The distances above are preferably 1 to 2 mm. However, the areas can also abut each other or spaced up to 5mm apart his.

Because the lugs 63, 65, 87 and 89 to the outside are not isolated and they on the half-elements 42 and 44 are tight, an electrical connection from the contact rail 30 via the sliding contacts (not shown), the holding strut 32 and 34, the holding cage 36 created for the two half elements 42 and 44.

Will the suspension shown in Figures 2 and 3 17 with the housing half-shells 38 and 40 according to FIG 1 first immersed in the nickel-containing electrolyte, are due to the relatively good coverage of nickel all exposed surfaces of the housing half-shells 38 and 40 with a nickel layer 130 (see FIG. 4) overdrawn. In the next step Immersion of the holding cage 36 with the housing half-shells 38 and 40 in the chromium-containing electrolyte 24 are the freely accessible areas of the housing half-shells 38 and 40 also covered with a chrome layer 132. The but only a short distance apart Areas 100 and 120 and 102 and 118 of the housing shells 38 and 40 are made of chrome because of its bad Wrapping poorly achieved, however, so that in these areas, the chrome layer 132 is relatively thin or does not exist at all.

FIG. 4 shows a detail of a closed housing, which consists of the two housing shells 38 and 40 is composed.

As shown in Figure 4, lies in the connection area of the two housing shells 38 and 40 die Nickel layer 130 free, and on these free areas was e.g. an electromagnetic Seal 134 applied, which thus with the deposited nickel layer 130 in direct contact is. As a result, there is only a small contact resistance from the nickel layer 130 to the electromagnetic Seal 134 in front, and the electromagnetic shield in the connection area between the parts of the housing half-shells 38 and 40 is improved.

The housing half-shells 38 and 40 in the present exemplary embodiment are made of magnesium, on which the intermediate layer can be directly galvanized. In one The embodiment half shells are not shown made of plastic. So on this one functional metal, e.g. Nickel, and a decorative Metal, e.g. Chrome, can be electroplated must have previously chemically a copper layer and in general in addition, a copper layer is applied galvanically become.

In the present exemplary embodiment, the housing half-shells were 38 and 40 during nickel plating and chrome plating at the same distance from each other arranged. The result of nickel plating can, however, especially with complex shapes in the connection area of the housing shells, improved if the distance during nickel plating is bigger. For example, the half elements 42 and 44 of the retainer cage 36 during nickel plating still be separate, so that the housing shells 38 and 40 are individually plated with nickel and the connection areas 100, 102, 118, 120 of the housing half-shells 38 and 40 are freely accessible. Only before galvanizing in Electrolyte 24 for the production of the decorative layer (in the above embodiment this was chromium-containing) could then the half elements 42 and 44 of the holding cage 36 merged and thereby the distance between the Areas 100, 102, 118 and 120 to the required degree be reduced.

Claims (13)

Process for metallizing molded parts, comprising the following steps: a) galvanic application of at least one electrically conductive, functional intermediate layer with low contact resistance; and b) galvanic application of a decorative layer;
characterized in that c) during the galvanic application of the decorative layer, an area (100, 102) of the molded part (38) is opposite an area (118, 120) of a counter element (40) at such a small distance that the galvanic application in this area is reduced. Process for metallizing molded parts, comprising the following steps: a) galvanic application of at least one electrically conductive, functional intermediate layer with low contact resistance; and b) galvanic application of a decorative layer;
characterized in that c) during the galvanic application of the decorative layer to an area (100, 102) of the molded part (38), an area (118, 120) of a counter element (40) is applied so that the galvanic application in this area is reduced. Method according to one of claims 1 or 2, characterized characterized in that the decorative layer chrome includes. Method according to one of the preceding claims, characterized in that it is the counter element (40) is also a molded part. A method according to claim 4, characterized in that the opposite or adjacent areas to complement each other shaped connection areas (100, 102, 118, 120). Method according to one of the preceding claims, characterized in that the intermediate layer Includes nickel. Method according to one of the preceding claims, characterized in that the molded parts made of plastic are. A method according to claim 7, characterized in that before the application of the intermediate layer, the method comprises the following steps: a) chemical application of a first metallic, preferably copper-containing base layer; and b) galvanic application of a second metallic, preferably copper-containing base layer. Method according to one of claims 1 to 6, characterized characterized in that the molded parts (38, 40) made of metal, are preferably made of magnesium. Method according to one of the preceding claims, characterized in that the distance between the areas during the galvanic application of the decorative layer is between 0 and 5 mm. Method according to one of the preceding claims, characterized in that it is in the molded parts complex molded parts, preferably housing shells (38, 40) for mobile phones. Method according to one of the preceding claims, characterized in that the distance between the areas during the galvanic application of the Intermediate layer is larger than during application the decorative layer. Process for making a completed Housing consisting of at least two housing parts with one conductive gap sealing the gap between the housing parts Seal, characterized in that the galvanization the housing parts (38, 40) by a method according to a of claims 1 to 12, with the areas in which the deposition of the decorative layer (132) is reduced, the electrically conductive seal (134) is applied.

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