CN115023051A - Three-dimensional curved surface circuit and production method thereof - Google Patents

Abstract

The invention discloses a three-dimensional curved surface circuit and a production method thereof, wherein the production method of the three-dimensional curved surface circuit comprises the following steps: plastic injection molding, stress relief, degreasing and deoiling, surface roughening, palladium precipitation and degumming, chemical nickel plating I, laser etching, thin copper electroplating, chemical nickel plating I I, chromium plating treatment and drying forming. The invention discloses a three-dimensional curved surface circuit which comprises a plastic layer, a nickel plating layer, a thin copper layer, a nickel plating layer and a chromium plating layer. The production method can improve the side flatness of the metal wiring in the later period and improve the circuit electrical performance of the whole device. Meanwhile, the cost of the used materials is low, the preparation method is simple, and large-area preparation and industrialization can be realized.

Description

Three-dimensional curved surface circuit and production method thereof

Technical Field

The invention relates to the technical field of three-dimensional curved surface circuits, in particular to a three-dimensional curved surface circuit and a production method thereof.

Background

The three-dimensional circuit is formed by manufacturing required patterns and wires on the surface of a three-dimensional workpiece by adopting a special processing procedure and directly welding electronic components on the curved surface of the workpiece. The mainstream three-dimensional circuit processing method in the current market mainly comprises the following steps:

1. a Laser Direct Structuring (Laser Direct Structuring) process of Germany LPKF company comprises the following steps: injection molding, laser activation, electroless copper plating and electroless nickel gold plating. The disadvantages are as follows: LDS particles need to be added to the raw material, which results in a high raw material cost.

2. The Two shot molding process of Sankyo Kasei company in Japan comprises the following steps: non-circuit part injection molding, electroless copper plating and electroless nickel gold plating. The disadvantages are as follows: the development cost is high and the process is complex.

3. Laser Resist Imaging (Laser selective Resist removal) process under Japan Song, comprising the steps of: injection molding of a workpiece, electroless copper plating, resist coating, selective resist removal by laser, etching and surface treatment (nickel, gold and the like). The disadvantages are as follows: the process cost and the material cost are high.

4. An AJ/Aerosol Jet (Aerosol direct Jet printing) process of OPTOMEC, USA, comprises the following steps: injection molding of a workpiece, spray printing of an aerosol coating, and sintering by using a xenon lamp or a laser or a baking furnace. The disadvantages are as follows: the three-dimensional layout capability is poor and the process is complex.

5. Plasma Innovations (Plasma coating) process by austria. The process uses a method of coating a conductive material by plasma under low temperature, micro and normal pressure to directly write a conductive structure, and an electric arc between an anode and a cathode generates plasma current, the energy of the plasma current melts input copper particles and sprays the melted copper particles onto a base material to directly form the conductive structure. The disadvantages are as follows: the circuit is rough, the precision is poor, the process is complex and the cost is high.

Therefore, a method for producing a three-dimensional curved circuit with simple process and low cost is needed to improve the batch production of the curved three-dimensional circuit.

Disclosure of Invention

In view of the above disadvantages or shortcomings of the prior art, the present invention provides a method for producing a three-dimensional curved circuit, which comprises the following steps: common injection molding, coarsening electroplating, laser etching and secondary electroplating. The process has the advantages of low material cost, simple process, flexible operation, suitability for sample pieces and batch production, and capability of solving the problems of high raw material cost, complex process, high cost and the like in the prior art.

In a first aspect, an embodiment of the present application provides a method for producing a three-dimensional curved surface circuit, including the following steps:

s1, plastic injection molding: selecting thermoplastic plastics as a base material, and carrying out molding treatment on plastic particles by using a base material molding device to obtain a plastic molded part;

s2, stress relief: ventilating and soaking the injection molded plastic molded part, and removing the internal stress of the plastic molded part after drying;

s3, degreasing: putting the plastic molded part into a chemical degreasing agent for chemical degreasing;

s4, surface roughening: coarsening the surface of the plastic formed part to increase the roughness of the surface;

s5, palladium precipitation and glue dissolution: performing colloid palladium activation treatment on the plastic molding part by using a colloid palladium activating agent, and then performing dispergation treatment;

s6, electroless nickel plating I: carrying out chemical nickel plating treatment on the plastic formed part after glue release;

s7, laser radium carving: performing laser etching treatment on the surface layer of the electroplated nickel to form an available electroplating area and a useless non-electroplating area on the surface of the plastic molded part;

s8, electroplating thin copper: carrying out copper pyrophosphate copper plating treatment and sulfate copper plating treatment on the plastic molded part subjected to laser etching;

s9, chemical nickel plating II: performing bright nickel treatment on the plastic molded part subjected to sulfate copper plating treatment;

s10, chromium plating treatment: carrying out chromium plating treatment on the plastic molded part subjected to the bright nickel treatment;

s11, drying and forming: and drying the plastic formed part subjected to chromium plating.

Further, the thermoplastic in S1 may be: ABS, polypropylene, polysulfone, polycarbonate, nylon, phenolic glass fiber reinforced plastic, polystyrene and their copolymer or blend, preferably ABS.

In the soaking step of S2 stress relieving, a glacial acetic acid solution with the solubility of 15mol/L is adopted.

Further, the chemical degreasing agent of S3 adopts an alkaline solution.

Further, the roughening treatment of S4 increases the roughness and the contact area of the surface layer to increase the bonding force between the plating layer and the plastic.

Further, the palladium precipitation and dispergation process of S5 is composed of a reduction-cleaning-palladium precipitation-dispergation process.

Furthermore, the current density of the S6 for chemical nickel plating is 3-5A/dm2, the voltage is 1.5-2V, the temperature is 33-38 ℃ for chemical nickel plating, and the time is 7-10 min.

In a second aspect, an embodiment of the present application provides a three-dimensional curved surface circuit, and the three-dimensional curved surface circuit is produced by using the production method of the three-dimensional curved surface circuit.

In a third aspect, an embodiment of the present application provides a three-dimensional curved surface circuit, which includes a plastic layer, a nickel plating layer, a thin copper layer, a nickel plating layer, and a chromium plating layer.

The beneficial effects of the invention are:

1. the production method of the patent is used for manufacturing the three-dimensional curved surface circuit, so that the side flatness of metal wiring in the later period can be improved, and the circuit electrical performance of the whole device is improved.

2. The three-dimensional curved surface circuit manufactured by the production method avoids the phenomena of looseness, bubbling, cracking and the like of the plated layer after electroplating, prolongs the surface durability of the product, and has excellent comprehensive performances of high temperature resistance, corrosion resistance and the like.

3. The production method of the patent has the advantages of low material cost, simple preparation method and capability of realizing large-area preparation and industrialization.

Drawings

FIG. 1 is a process diagram of a method for producing a three-dimensional curved circuit according to the present invention;

fig. 2 is a schematic structural diagram of a three-dimensional curved surface circuit of the present invention.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

The invention provides a three-dimensional curved surface circuit and a production method thereof. The curved surface three-dimensional circuit consists of a plastic layer, a nickel plating layer, a thin copper layer, a nickel plating layer and a chromium plating layer.

The production implementation process of the three-dimensional curved surface circuit comprises the following steps:

s1: plastic injection molding: and (3) selecting thermoplastic plastic as a base material to melt, injecting the molten plastic into a set plastic product mold by using pressure, and cooling and molding to obtain the plastic part. The thermoplastic may be: ABS, polypropylene, polysulfone, polycarbonate, nylon, phenolic glass fiber reinforced plastic, polystyrene and their copolymer or blend, preferably ABS. The ABS plastic is a terpolymer of three monomers of acrylonitrile (A), butadiene (B) and styrene (S).

S2: stress relief: placing the plastic part subjected to injection molding in a ventilated place and standing still for 12-24 hours, wherein the temperature of the placed environment is kept between 15 ℃ and 35 ℃ to reduce the internal stress of the plastic decorative plate, and after the plastic part meets the requirement of the placement time, placing the plastic decorative plate into a glacial acetic acid soaking pool with the solubility of 15mol/L for soaking for 20-30 minutes. And finally, taking out the plastic part, and hanging the plastic part in a dark room for drying in the shade.

S3: degreasing: placing the plastic part subjected to stress relief in an oil relief tank, wherein the main components of an oil relief agent comprise 20-30g/L of sodium hydroxide solution, 30-40g/L of sodium carbonate solution, 20-30g/L of sodium phosphate solution and 3-5g/L of anionic polyacrylamide, the temperature of the oil relief agent is controlled to be 50-60 ℃, the time is controlled to be 5-10 minutes, the plastic part is placed in an ultrasonic cleaning machine for cleaning after oil relief is finished, and finally 100% tap water is adopted for spraying and washing, the spraying and washing time is 3-6 minutes, until no oil relief agent is left on the surface.

S4: surface roughening: sending the cleaned plastic plaque into a roughening tank for roughening treatment, pouring roughening liquid into the roughening tank and immersing the plastic plaque, wherein the roughening liquid mainly comprises a solution formed by mixing 390-410g/L chromic acid, 380-420g/L sulfuric acid and a proper amount of atomizing agent, and the aqueous solution is properly adjusted and added according to the process. The temperature of the solution is 65-75 ℃, the coarsening time is 8-15 minutes, and then the solution is put into a cleaning tank for cleaning.

S5: depositing palladium and dispergating: and (2) placing the plastic part after coarsening into a reduction tank for treatment, adding a reducing agent into the reduction tank to immerse the plastic part, wherein the reducing agent is formed by mixing 14-20mL/L hydrochloric acid and 0.3-0.5mL/L hydrazine hydrate as main components, the reduction temperature is the same as room temperature, the reduction time is 2-3 minutes, and then placing into a cleaning tank for cleaning. And then sending the plastic part into a palladium activation tank containing a palladium activation solution, wherein the palladium activation solution is a mixed aqueous solution containing palladium ions, and the mixed aqueous solution contains 12-30 ppm of the palladium ions, 220-320 ml/L of hydrochloric acid and 2-6 g/L of stannous chloride. The palladium activation temperature is 26-32 ℃, the palladium activation time is 1-6 min, and then the palladium is sent into the cleaning tank again to be cleaned. And finally, treating the plastic part in a degumming tank, adding the degumming tank into the degumming tank to submerge the plastic part, wherein the main component of the degumming solution is 150-300g/L hydrochloric acid, the degumming temperature is 50-60 ℃, and the degumming time is 3-5 minutes.

S6: chemical nickel plating: the plastic part subjected to palladium precipitation and glue dissolution is placed into an electroplating bath for treatment, and an electroplating nickel solution is added into the electroplating bath, wherein the main components of the electroplating nickel solution are 25-32g/L of nickel sulfate, 10-16g/L of sodium hypophosphite, 35-50g/L of sodium citrate and 35-50g/L of ammonium chloride. The current density is 3-5A/dm2, the voltage is 1.5-2V, the chemical plating temperature is 33-38 deg.C, and the time is 7-10 min.

S7: laser etching: firstly, setting a circuit drawing, and removing an unnecessary electroplated layer on a nickel-plated plastic piece by using a laser engraving machine. The utilization is accurate location on laser radium carving machine, and the characteristic position of taking a candid photograph product, and the high-speed galvanometer scanner on the laser radium carving machine carries out position control to the deviation in the compensation location. The energy of the laser is 15W-20W, the frequency of the laser is 40KHZ, the speed of the laser is 2000-2500mm/s, and the filling interval of the laser is 0.04 mm. Eventually, a usable plated area and a useless non-plated area are formed on the surface of the plastic part.

S8: electroplating thin copper: putting the plastic part subjected to laser engraving into an electroplating bath for treatment, and adding an electroplating copper solution into the electroplating bath, wherein the main components of the electroplating copper solution are 80-150g/L copper sulfate, 0.005-0.02g/L sodium thiolpropanate, 15-30g/L sodium sulfate, 60-80g/L hydroxyethylidene diphosphonic acid, 20-30g/L hydrochloric acid, 30-50g/L sulfuric acid and 40-60g/L deionized water, and the pH value is adjusted to be 6-8. The current density during electroplating is 1-2A/dm2, and the electroplating time is 10-15 minutes.

S9: chemical nickel plating: the plastic part which is finished by electroplating the thin copper is put into an electroplating bath for treatment, and electroplating nickel solution is added into the electroplating bath, wherein the main components of the electroplating nickel solution are 25-32g/L of nickel sulfate, 10-16g/L of sodium hypophosphite, 35-50g/L of sodium citrate and 35-50g/L of ammonium chloride. The current density is 3-5A/dm2, the voltage is 1.5-2V, the chemical plating temperature is 33-38 deg.C, and the time is 7-10 min.

S10: and (3) chromium plating treatment: the plastic part after nickel plating is placed into an electroplating bath for treatment, and chromium electroplating solution is added into the electroplating bath, wherein the main components of the chromium electroplating solution are 0-15g/L of chromium sulfate, 1-5g/L of acetic acid, 1-5g/L of boric acid, 100-plus-180 g/L of potassium sulfate, 1-5g/L of sodium vinyl sulfonate, 0.5-1g/L of sodium tartrate and 0.5-1g/L of potassium sulfamate, the pH value of the solution is controlled to be 2-3 by using water and 30% sulfuric acid for regulation. The current density is 5-10A/dm2, the voltage is 3.3-5.1V, and the electroplating time is 5-10 minutes.

S11: drying and forming: and (3) putting the plastic part subjected to the chromium electroplating treatment into a drying oven with an exhaust device, setting the drying temperature to be 50-60 ℃ and the drying time to be 1-1.5 h.

In the invention, in the roughening treatment and plating processes, specific treatment liquid and electroplating liquid are selected, so that the binding force between the plating layer and the plastic is increased, the phenomena of looseness, bubbling, cracking and the like of the plating layer after electroplating are avoided, the surface durability of the product is prolonged, and the product has excellent comprehensive performances of high temperature resistance, corrosion resistance and the like.

And laser is carried out on the surface of the plastic piece after the chemical nickel plating, and the part which does not need to be reserved is removed in a laser etching mode, so that a usable electroplating area and a useless non-electroplating area are formed on the surface of the plastic piece. And then electroplating again, wherein the electroplating method comprises the step of firstly carrying out electroplating thin copper treatment on an electroplating area on the surface of the plastic part by using acid copper, wherein the acid copper can dissolve nickel overflowed in the chemical nickel plating process, so that the flatness of a nickel layer is improved, the side flatness of metal wiring in the later period is further improved, and the circuit electrical performance of the whole device is improved.

Thus, the conducting wire and the pattern with the electrical function are manufactured on the plastic with the curved surface, and the components are directly installed on the shell and are electrically interconnected, so that the electrical interconnection function of the circuit board, the function of supporting the components, the support and protection function of the plastic shell, the functions of shielding, antenna and the like generated by the combination of the mechanical entity and the conductive pattern are integrated into a whole, and the circuit with the three-dimensional curved surface is formed. Meanwhile, the material cost is low, the preparation method is simple, and large-area preparation and industrialization can be realized.

The above descriptions are only examples of the present invention, and common general knowledge of known specific structures, characteristics, and the like in the schemes is not described herein too much, and it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Without departing from the invention, several changes and modifications can be made, which should also be regarded as the protection scope of the invention, and these will not affect the effect of the invention and the practicality of the patent.

Claims (9)

1. The production method of the three-dimensional curved surface circuit is characterized by comprising the following steps of:

s1, plastic injection molding: selecting thermoplastic plastics as a base material, and carrying out molding treatment on the plastic particles by using a base material molding device to obtain a plastic molded part;

s2, stress relief: ventilating and soaking the injection molded plastic molded part, and removing the internal stress of the plastic molded part after drying;

s3, degreasing: putting the plastic molded part into a chemical degreasing agent for chemical degreasing;

s4, surface roughening: coarsening the surface of the plastic formed part to increase the roughness of the surface;

s5, palladium precipitation and glue dissolution: performing colloid palladium activation treatment on the plastic molding part by using a colloid palladium activating agent, and then performing dispergation treatment;

s6, electroless nickel plating I: carrying out chemical nickel plating treatment on the plastic formed part after glue release;

s7, laser radium carving: performing laser etching treatment on the surface layer of the electroplated nickel to form an available electroplating area and a useless non-electroplating area on the surface of the plastic molded part;

s8, electroplating thin copper: carrying out copper pyrophosphate copper plating treatment and sulfate copper plating treatment on the plastic molded part subjected to laser etching;

s9, chemical nickel plating II: performing bright nickel treatment on the plastic molded part subjected to sulfate copper plating treatment;

s10, chromium plating treatment: carrying out chromium plating treatment on the plastic molded part subjected to the bright nickel treatment;

s11, drying and forming: and drying the plastic formed part subjected to chromium plating.

2. The method for producing a three-dimensional curved surface circuit according to claim 1, wherein the thermoplastic in S1 is selected from the group consisting of: one or more of ABS, polypropylene, polysulfone, polycarbonate, nylon, phenolic glass fiber reinforced plastic, polystyrene and the like.

3. The method for manufacturing a three-dimensional curved surface circuit according to claim 2, wherein the soaking step for stress relief of S2 is performed using a glacial acetic acid solution having a solubility of 15 mol/L.

4. The method for producing a three-dimensional curved surface circuit according to claim 3, wherein the chemical oil remover of S3 is an alkaline solution.

5. The method for manufacturing a three-dimensional curved surface circuit according to claim 4, wherein the roughening treatment of S4 increases the bonding force between the plating layer and the plastic by increasing the roughness and contact area of the surface layer.

6. The method for producing a three-dimensional curved-surface circuit according to claim 5, wherein the palladium deposition and dispergation process of S5 is composed of a reduction-cleaning-palladium deposition-dispergation process.

7. The method for producing a three-dimensional curved surface circuit according to claim 6, wherein the current density of the electroless nickel plating of S6 is 3-5A/dm2, the voltage is 1.5-2V, the temperature of the electroless nickel plating is 33-38 ℃, and the time is 7-10 min.

8. A three-dimensional curved surface circuit, characterized by being produced by the production method of the three-dimensional curved surface circuit according to any one of claims 1 to 7.

9. A three-dimensional curved surface circuit is characterized by comprising a plastic layer, a nickel plating layer, a thin copper layer, a nickel plating layer and a chromium plating layer.

Images