JPH0429754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a timepiece dial (including a so-called parting plate).

More specifically, it is manufactured by forming the surface patterns, letters, symbols, patterns, and marks on a watch dial using photosensitive resin and a resin mold on a base material substrate, and then metallizing the surface. The purpose is to provide a low-cost watch dial with a wide variety of designs that cannot be achieved using conventional methods.

Since the dial of a watch is the face of the watch, it needs to have excellent functionality as well as a textured design.Moreover, with the diversification of tastes, there has been a demand for production of a wide variety of watches in small quantities. How to make such a dial at a low price is becoming an important issue.

First, in the conventional manufacturing method of watch dials, the problem from the viewpoint of cost reduction is that it is not possible to save labor through mechanization and automation.

The reason for this is that high-variety, low-volume production is required, and the processing equipment differs depending on the type of surface finish. Combining these, automating them, and creating a production line requires huge development costs and capital investment. It's impossible.

A conventional dial manufacturing method will be described in detail. There are two main ways to make the base plate of the current dial.
It can be divided into two methods. There are two types of dials: Butler-finished ones, where the pattern on the base surface of the dial is typically a hairline pattern or radial pattern, and stamped ones, which are surface-embossed.

First, the former method will be explained in the order of steps.

First, punch holes in the outer diameter and center of the raw material plate using a press punch. (Figure 1-1, hereinafter expressed as 1-)
Next, attach the fixed feet 2 to the base board. (1-) There are currently two methods of attaching feet. First, I will explain how to attach it with silver solder.
The legs are made of copper pipes filled with silver solder. First, the legs are resistance welded and the copper pipes are temporarily attached to the base plate. Next, it is passed through a furnace at 800℃ for 5 minutes to melt the silver solder in the legs and completely fix the legs to the base plate. The feature of this method is that there is almost no deformation (foot deco) on the surface of the base plate 1 where the feet are attached, but because the conditions for melting the silver solder are high temperature (800°C), the surface of the base plate 1 is For example, if the material of the base plate 1 is BS (brass), the hardness of the base plate 1 is 180Hv in Bitsukas hardness before going through the furnace, but after passing through the furnace it becomes 80Hv and the base thickness changes. cause restrictions. Base thickness less than 30/100 is not allowed.

Furthermore, high-temperature processing at 800°C requires large equipment.

Another method is to attach the legs using resistance welding. In this method, the legs 2 are made of pure copper with a pointed tip, and a current is passed between the base plate 1 and the legs 2 to apply pressure while attaching them. In this method, the tip of the foot 2 has a high resistance, so the tip of the foot 2 is locally heated and attached.

The feature of this method is that heat is generated only at the tips of the legs 2 and is localized heating, so the strength of the base plate 1 is not weakened by attaching the legs 2. However, a drawback is that the surface of the base plate 1 is deformed (foot deformation) at the part where the foot is attached because pressure is applied to increase the fixing force between the base plate 1 and the foot 2 when the foot is attached. In other words, on the opposite side of the base plate 1 where the legs 2 are attached, 10 to 20
As a result, the surface becomes tight, which is a problem in terms of appearance, and requires a surface preparation process to remove the tightness.

Next, after attaching the feet, the surface of the base board is sanded with a cloth to create a mirror surface.

This fabric polishing process is a highly skilled work, as even the slightest scratches will result in poor appearance during the butler finishing process in the subsequent process.
Also, if there are material defects (impurities or inclusions) in the material of the base plate, it will not be possible to create a mirror surface.
Specially tempered materials with few impurities are required.

Next, the Butler pattern is created using a special processing machine. (1-) There are currently 10 types of Butler patterns, with radial patterns and hairline patterns being the most representative patterns, each of which requires a dedicated processing machine.

Next, honing is performed using special equipment.

This honing process is also an important process in determining the texture of letters, and surface conditions with different textures are possible depending on the type of abrasive grain, grain size, and honing time, and many types of honing are actually performed. There is.

Next, add the plating. (Underlay: Ni plating, finishing plating: Ag plating, An plating, etc.) Next, spray painting and printing with latscar completes the printed type dial. (1-) Next, the latter method will be explained in the order of steps. First, a hole is made on the raw material plate using a press. (2-) Next, a sintering treatment is performed. This step is necessary to facilitate the next surface pressing process.

Next, the base plate 1 is patterned by surface pressing. (2-) Surface pressing is a process in which a pattern is applied to the surface of a mold, and the pattern is cold pressed (100 tons) to transfer the patterned surface of the mold onto the base plate 1.

This surface stamping process is performed using a 100-ton friction press, which is extremely large and heavily equipped for processing small dials.

Next, punch out the center hole and outer diameter of the base plate using a press. (2-) Next, add the feet. (2-) Attach the legs with silver solder. In this case, it is not possible to use resistance welding to attach the legs. The reason for this is that the surface of the base plate 1 has already been finished with a pattern, so if the legs are attached using resistance welding,
This is because it is impossible to remove the burrs that occur on the surface of the base plate to which the legs 2 are attached.

Next, the printed dial is completed by plating, painting, and printing. (2-) As mentioned above, in the current dial manufacturing method, stamped products require a 100-ton friction press, and Butler pattern products require a 100-ton friction press, depending on the type of pattern.
It requires several types of specialized processing machines, and each process relies on the skill level of the operator.

In addition, there are two methods for attaching the feet: brazing and resistance welding.
There are two methods, and it is currently impossible to focus on just one.

As mentioned above, it is technically difficult to automate and create production lines for processes that involve a wide variety of manufacturing methods, as well as processes that require heavy processing equipment and many large machines, and even if it were possible, it would require enormous development costs. Capital investment is required.

The present invention aims to solve the above-mentioned problems in the manufacturing method of watch dials for a wide variety of products in small quantities.

In other words, the surface pattern applied to the watch dial,
By adopting a manufacturing method for a watch dial, which is characterized by molding the unevenness of letters, symbols, patterns, marks, etc. onto the display member substrate using a photosensitive resin mold, and then metallizing the surface, the above-mentioned features can be achieved. This is an attempt to solve the problem.

The method for manufacturing a timepiece dial according to the present invention will be explained in detail.

A photosensitive resin monomer is sandwiched between the base substrate of the watch dial and a resin mold on which the patterned surface of the desired watch dial is applied to a predetermined thickness, and ultraviolet rays are applied to the photosensitive resin monomer through the resin mold surface. After curing the photosensitive resin monomer by irradiating (UV),
When the resin mold is peeled off, a photosensitive resin having the patterned surface of the resin mold transferred thereon is formed on the substrate of the clock display member.
Next, a thin metal layer is formed on the patterned photosensitive resin surface to form the desired watch dial.

Since the dial manufacturing method of the present invention forms a thin metal layer on the surface of a photosensitive resin, the adhesion between the photosensitive resin and the thin metal layer is important.

Generally, in the case of plastic plating in which a thin metal layer is formed on a resin, the resin surface is chemically etched as a means of improving adhesion to improve adhesion through a wedge effect.

However, in the case of watch dials, if the resin surface is chemically etched to the extent that a wedge effect occurs, the appearance of the patterned surface will be impaired, making it impossible to put it to practical use. In the present invention, when forming a thin metal layer on a resin surface by wet plating, it is possible to obtain excellent adhesion between the resin surface and the metal thin layer without impairing the appearance quality of the resin surface.

That is, it was discovered that good adhesion can be obtained by limiting the thickness of the subplated Ni plating layer to a range of 3000 Å to 1500 Å.

The underlying Ni plating layer is composed of two layers: an electroless Ni-P alloy plating layer and an electrolytic Ni plating layer.The electroless Ni-P alloy plating is performed by metallizing the photosensitive resin surface. Electrolytic Ni plating is necessary to apply finish plating of Ag, Aμ, etc. on top of the subplated Ni plating.

The upper limit of the Ni plating layer is 3000 Å, and if the thickness is greater than this, the adhesion between the photosensitive resin and the metal layer will deteriorate. In other words, if you cut a metal layer with 10 knives at right angles at 1 mm intervals, stick sellotape on the surface, and peel it off, the metal layer will hardly stick to the sellotape side if the thickness is less than 3000 Å, but if the thickness is less than 3000 Å,
When the thickness exceeds 1.5 Å, a metal layer will adhere to the cellophane tape side.

The adhesion area increases as the thickness increases. The lower limit of the Ni plating layer is 1500 Å, and if the thickness is less than this, the resistance value will increase, causing uneven plating in the final electrolytic plating, which will impede the appearance quality of the final plating.

This tendency is particularly noticeable in the case of Ag plating, black Ni plating, etc., which have poor shedding.

The first feature of the watch dial of the present invention is
In addition, display members with any pattern of surface finish can be manufactured with the same equipment as long as a resin mold is prepared. Moreover, the process of curing the UV resin can be done in a short time, and the equipment is much lighter compared to conventional machining methods.

Therefore, mechanization and automation are easy, and a production line in which processes are directly connected becomes possible.

Second, the method for manufacturing a watch dial according to the present invention allows for an expanded variety of designs.

In other words, as long as there is one master resin mold used in the method for manufacturing a watch dial of the present invention, the resin mold can be easily manufactured by, for example, thermal polymerization using a casting method, and by repeated use, a large number of resin molds can be manufactured. You can make several resin molds. A large number of display members can be made from one resin mold by repeated use.

As mentioned above, even if the production of the master is expensive, it is possible to produce many watch dials from one master using resin molds, so the production cost of the master can be ignored.

Therefore, designs that could not be adopted by conventional methods for manufacturing timepiece dials due to restrictions in terms of man-hours can be realized by the method for manufacturing timepiece dials of the present invention.

The method for manufacturing a timepiece dial according to the present invention will be described in more detail based on Examples.

Example 1 First, a base plate 1 is made from a steel material with a thickness of 20/100 mm. (3-) The materials used for the base plate are limited to nickel silver and brass in conventional dial manufacturing methods, but the material is specially tempered for dial plates with fewer material defects. However, the base plate material in the dial manufacturing method of the present invention is not limited in terms of material and general materials can be used, so the cost of the base plate material can be significantly reduced. For example, the nickel silver used in the conventional method costs 7 yen per sheet, but the steel material produced by the manufacturing method of the present invention costs 2 yen per sheet.

Next, attach the fixed feet to the base plate using resistance welding. (3-) When resistance welding, deformation occurs on the surface of the base plate 1 at the part where the feet are attached (the amount of deformation is 1/100 to 2/100 mm), but in the next process the base plate surface is exposed to light. This does not pose a problem because a synthetic resin is formed.

Therefore, when attaching fixed legs using resistance welding in the conventional manufacturing method, it is necessary to smooth out the protrusions that occur on the base plate after welding, but the manufacturing method of the present invention Then there's no need for that.

Next, drop an appropriate amount of Asahi Kasei XFP700 photosensitive resin onto the base plate 1, place the CR-39 resin mold 3 with the desired surface pattern on top of it, and 5/10 photosensitive resin monomer between
Sandwich it to a thickness of 0 mm. At this time, air should not be allowed to enter between the base plate 1 and the resin mold 3.

Next, ultraviolet rays (UV) are irradiated from the upper surface of the resin mold 3 to harden the photosensitive resin monomer. (3-
) The conditions for irradiating ultraviolet rays are 20 mw of UV intensity.
Cures very quickly within 30″.

The photosensitive resin used above has good releasability from the resin mold, good adhesion to the base substrate, good adhesion to the metalized thin layer processed in the subsequent process, and good adhesion to the metallized thin layer processed in the subsequent process. The photosensitive resin is selected in consideration of the fact that the photosensitive resin will not be chemically attacked by the paint solvent.

The material for the resin mold should be one that can be easily made into a resin mold (for example, by thermal polymerization using a casting method), one that does not react with the photosensitive resin used, one that has good mold releasability from the cured photosensitive resin, and one that has a wavelength around 365 mm. The material is selected taking into consideration factors such as its good transmittance of ultraviolet rays.

The method for manufacturing the resin mold will be described.

First, a master is made of metal, a resin for casting is poured between the metal master and the glass plate, and after it is thermally polymerized and cured, the metal master and glass plate are peeled off to create a resin mold. Since the metal master can be used repeatedly, it is possible to manufacture many resin molds from one metal master.

In addition to CR-39, cast-type acrylic resin,
Transparent type silicone rubber resin for casting can be used as the resin mold of the present invention.

Next, after curing, remove the base plate from the resin mold.
A photosensitive resin is formed on the base plate, and the resin surface is reproduced to be the same as the master onto which the patterned surface of the resin mold is transferred. (3-) It is possible to improve the adhesion between the photosensitive resin and the base plate by adding a material that has good adhesion to metal into the photosensitive resin, and we would like to further improve the adhesion. In this case, after welding the fixed legs, coat the metal with an adhesive that has good adhesion, and allow the adhesive to react with the photosensitive resin in a semi-hardened state to achieve full adhesive strength.

Next, the photosensitive resin with the pattern transferred to the base plate is irradiated with ultraviolet light (365 mm) to completely polymerize and harden the photosensitive resin. The irradiation conditions were an intensity of 20 mw.

Next, the surface of the photosensitive resin onto which the pattern has been transferred is subjected to metallization treatment. (3-) Wet plating method and metallization method are available.
A dry plating method can be used, but a wet plating method is preferable in terms of adhesion between the photosensitive resin and the metalized thin layer.

For wet plating, electroless Ni plating is optimal in terms of the appearance of the plating layer and the adhesion between the plating layer and the photosensitive resin layer.

First, before applying plating, pretreatment is performed. Pretreatment involves immersion in a tin chloride solution (1% solution) for 1 minute, washing with water, immersion in a palladium chloride solution for 1 minute, washing with water, and then drying.

After the above pretreatment, the plate is immersed in electroless Ni-P alloy plating (S-680 manufactured by Kanigen Co., Ltd.). Plating conditions were 50℃ and 1 minute. The thickness of the Ni-P layer (P content: 8%) under these conditions is 500 Å.

Next, electrolytic Ni plating is performed using the usual electrolytic plating method.

The thickness of electroless Ni-P alloy plating is as follows:
The thinner the layer is, the better the adhesion between the photosensitive resin and the metal thin layer will be if Ni plating is possible.

Electrolytic Ni plating is possible and the thickness range with good adhesion is 200 Å to 700 Å, preferably 400 Å to 600 Å.
It is Å.

Next, electrolytic Ni plating is performed. The purpose of the sub-electrolytic Ni plating is necessary for the next finishing electrolytic plating of Ag, Aμ, etc. That is, it is not possible to directly apply finish plating on electroless Ni--P alloy plating because there is a problem in terms of coverage of the plating. The reason why the roundness of the finish plating is poor is that electroless Ni-P alloy plating contains P, so the resistance value is 10 times higher than that of electrolytic Ni plating, and the thickness is very thin. by.

For electrolytic Ni plating, Watsuto bath is preferable from the viewpoint of plating stability.

The composition and conditions for electrolytic Ni plating are as follows.

Nickel sulfate hexahydrate 225g / Nickel chloride hexahydrate 40g / Boric acid 25g / Brightener 7g / PH 4.3 Liquid temperature 50℃ Current density 1A/dcm ^2The thickness of electrolytic Ni plating under the above conditions is 3000Å
Plate to within the range of 1500Å. The upper limit of 3000 Å is limited by the plating adhesion between the photosensitive resin and the thin metal layer, and the lower limit of 1500 Å is limited by the roundness of the final plating.

Next, perform finishing plating. Types of finish plating for dial plates include Ag plating, Aμ plating, black Ni plating, etc., and the plating thickness is within the range that can achieve the color tone.
A thickness of about 500 Å is desirable.

Next, after metallization, painting, printing, and cutting out the outer diameter complete a printing type dial plate with a surface pattern according to the manufacturing method of the present invention.
(3-) Regarding the completed printing type dial plate above,
When conducting the adhesion test using cellophane tape as described above, there was no development in which the metal layer peeled off on the cellophane side, and a dial plate with good adhesion between the photosensitive resin and the thin metal layer was obtained.

The above example is an example of a printing type dial plate with a surface pattern;
A dial plate with convex and concave shapes such as patterns and marks can also be manufactured by the same method as in the above embodiments if a resin mold is made.

As described above, the photosensitive resin and resin mold of the present invention are used to form irregularities such as surface patterns, letters, windows, marks, symbols, and patterns on a base substrate, and the surface is metallized. The manufacturing method for watch dials uses a simple single device that can efficiently manufacture dials with a variety of designs, and requires heavy equipment that is mainly machined in the past, and multiple machines are used in the same process. This represents an innovation in the method of manufacturing watch dials, compared to methods of manufacturing dials that require additional equipment.

In other words, the method for manufacturing watch dials of the present invention is capable of unmanned operation using a single line with light equipment, capable of handling high-mix, low-volume production, eliminating the need for heavy equipment, enabling a significant reduction in manufacturing delivery time, and requiring less factory space. Able to respond to diversification and expansion of design variety Reduction of related expenses by simplifying logistics Eliminates the need for skilled workers.

In these respects, this manufacturing method can be said to be significantly superior to conventional methods for manufacturing watch dials.

As described above, the method for manufacturing a watch dial of the present invention provides surface patterns, characters,
The irregularities of windows, symbols, patterns, and marks are molded onto the dial base plate using photosensitive resin and a resin mold, and a conductive thin film layer is formed by electroless plating on the transferred resin surface. A watch face plate comprising: forming a base nickel plated thin film layer on the surface of the body thin film layer by electrolytic plating, and forming a finishing plated thin film layer on the base nickel plated thin film layer by electrolytic plating. In the manufacturing method, by setting the thickness of the underlying nickel plating thin film layer to 1,500 to 3,000 Å, the adhesion between the photosensitive resin surface and the metal plating layer is improved, and the metal plating layer becomes photosensitive during the manufacturing process. The watch face plate obtained by the method of manufacturing a watch face plate of the present application eliminates the problem of swelling caused by peeling off from the surface of the plastic resin, and is resistant to environmental changes during use.
In particular, it exhibits the unique effect of eliminating any blistering defects even when subjected to temperature changes.

[Brief explanation of drawings]

Figures 1-- are cross-sectional views of the manufacturing process of a conventional butler-finished type dial, Figures 2-- are sectional views of the manufacturing process of a stamped-type dial using conventional surface stamping, and Figures 3-- FIG. 3 is a cross-sectional view of a timepiece character manufacturing process according to the manufacturing method of the present invention. 1 is a base plate, 2 is a fixed foot, 3 is a paint layer, 4 is a resin mold, 5 is a photosensitive resin, and 6 is a metallized thin layer.

Claims (1)

[Claims] 1 After pressing and transferring the resin mold 4 having the unevenness onto the photosensitive resin 5 on the dial base plate 1 and curing it, a conductive thin film is formed on the surface of the photosensitive resin 5 with the unevenness formed by electroless plating. forming a base nickel plating thin film layer on the surface of the conductor thin film layer by electrolytic plating, and forming a final plating thin film layer on the base nickel plating thin film layer by electrolytic plating. In the method for manufacturing a watch dial, the thickness of the underlying nickel-plated thin film layer is 1500 mm.
A method for manufacturing a watch dial, characterized in that the thickness is ~3000Å.