JPS6070198A - Production of dial for timepiece - Google Patents

Abstract

PURPOSE:To produce a dial having a wide variety of design at a low cost in the stage of producing the dial for timepieces by forming ruggedness such as a surface pattern, window, symbol, figure, mark, etc. of the dial of a photosensitive resin and a resin mold on a base plate and subjecting the surface to a metallizing treatment. CONSTITUTION:A base plate 1 of a dial for timepieces is manufactured of an inexpensive steel sheet or the like and fixing legs are attached by welding thereto. A suitable amt. of a photosensitive resin 5 is dropped onto the surface of the plate 1 and a resin mold 4 formed with a desired surface pattern is placed thereon then UV light is irradiated tereto to cure the resin 5. The plate 1 is stripped from the mold 4 after curing and the UV light is irradiated to the resin 5 transferred in pattern to the plate to polymerize and cure thoroughly the resin. Electroless Ni-P alloy plating and electrolytic block Ni plating are performed continuously in succession thereto and finally Ag, Au and black Ni are plated as finish plating to form a metallized layer 6. The dial is subjected to painting 3 and printing and is thus completed.

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, along with its functions,
It is necessary to have an excellent texture design, and with the diversification of tastes, there is a demand for production of a wide variety of types in small quantities, and it is important to find out how to make such a dial at a low price. This is becoming a major issue.

First, the problem with the conventional manufacturing method of watch dials from the perspective of cost reduction is mechanization.

The problem lies in the inability to save labor through automation.

The reason for this is that the processing equipment is different depending on the type of surface finish, whether it is high-variety, low-volume production or not. It is impossible.

A conventional dial manufacturing method will be described in detail.

The method of making the base plate of the current dial can be roughly divided into two methods. There are two types of dials: Patola-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 stamped.

First, the former method will be explained according to the process order.

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 plate. (1-■) The method of attaching the feet is currently 2.
Two methods have been adopted.

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, the legs are passed through a furnace at 800 degrees for 0.5 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 (800'0), the base plate 1 For example, if the material of the base plate 1 is BS (brass), the hardness before passing through the furnace was 180 HV on the Picchus scale, but after passing through the furnace, it becomes aouv and the base thickness changes. cause restrictions. Base thickness below 3o/1oo is not allowed.

Further, high temperature treatment at 800°0 requires a large-sized apparatus.

Another method is to attach the legs using resistance welding. Make feet 2 of pure copper with a sharpened tip and attach base plate 1.
In this method, an electric current is passed between the feet 20 and the feet are held together while applying pressure. 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 the heat is generated only at the tip of the foot 2, and it is a local heating, so the strength of the base plate 10 will not be weakened by attaching the foot 2.However, as a disadvantage,
In order to apply pressure to increase the fixing force between the base plate 1 and the feet 2, the foot attachment sometimes causes deformation (leg deformation) on the surface of the base plate 1 where the foot is attached. In other words, 10 to 20
A protrusion appears on the surface of μ, which is a problem in terms of appearance, so a surface preparation process is required to remove the protrusion.

Next, the surface of the base plate is polished with a separate cloth to create a mirror surface.

The fabric polishing process is an advanced process that requires a high level of skill, as if even the slightest scratch remains, it will result in poor appearance during the polishing process in the later process. However, if there are material defects (impurities or inclusions), it is impossible to achieve a mirror finish, so a special tempered material with few impurities is required.

Next, a pattern is created using a special processing machine.

(1-■) There are currently 10 types of patterns, the typical patterns being radial patterns and hairline patterns, each of which requires a dedicated processing machine.

Next, honing is performed using special equipment.

This honing process also determines the texture of the dial. 5- This is an important process. Depending on the type and diameter of the abrasive grains and the honing time, it is possible to create a surface with a different texture. In reality, many types of honing are performed. It's showing up.

Next, apply plating. (Underlay HNi plating, final plating: Ag plating, An plating, etc.) Next, lacquer is sprayed, painted, and printed to complete a printed dial. (1-■) Next, the latter method will be explained according to 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 pressing. (2-
■) Surface pressing processing involves applying a pattern to the surface of a mold, pressing the pattern in a cold press (100 tons), pressing the patterned surface of the mold to
1.

The surface stamping process is carried out using a 100-ton fringe 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 since the surface of the base plate 1 has already been finished with a pattern, when the feet are attached using resistance welding, it is impossible to remove the scratches that occur on the surface of the base plate to which the feet 2 are attached. be.

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 Patola-patterned products require 10 types of special processing machines, depending on the type of pattern. Moreover, each process relies on the skill level of the worker.

In addition, there are two processes for foot attachment: brazing and resistance welding, and it is currently impossible to limit the process to just one.

As mentioned above, we can automate processes that involve a wide variety of manufacturing methods, as well as those that require heavy equipment and large-scale processing equipment.
It is technically difficult to create a line, and even if it were possible, it would require huge development costs and capital investment.

The present invention aims to solve the problems described above in the manufacturing method of watch dials of various kinds and in small quantities.

In other words, the surface pattern applied to a 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 layer is sandwiched to a predetermined thickness between the base substrate of the watch dial and the resin case on which the patterned surface of the desired watch dial is applied, and the photosensitive resin monomer is passed through the resin mold surface. After curing the photosensitive resin layer by irradiating it with ultraviolet rays (UV), the resin mold is removed, and a photosensitive resin layer with the patterned surface of the resin mold transferred onto the substrate of the clock display member is formed. 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 layer and the thin metal layer is important.

Generally, in the case of plating, which forms a thin metal layer on resin,
As a means of improving adhesion, the resin surface is chemically etched 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. According to 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 thin metal layer without impairing the appearance quality of the resin surface.

In other words, the thickness of the Nt plating layer is 3.00 OA.
This is because it was discovered that good adhesion can be obtained by limiting the thickness to a range of 9- to 1.500 λ.

The structure of the subplated Nl plating layer is composed of two layers: an electroless Nl -P alloy plating layer and an electrolytic Nl plating layer.The electroless Nl -P alloy plating is applied to metallize the photosensitive resin surface. electrolytic N1 plating is
This is necessary for finishing plating with Ag, Aμ, etc. on top of the first plating.

The upper limit of the Nt plating layer is 300 OA, and if the thickness exceeds this value, the adhesion between the photosensitive resin and the metal layer will deteriorate.

In other words, if you cut the metal layer with 10 knives at right angles at %1111 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 3.000A. However, when the thickness exceeds 4oooA, a metal layer adheres to the cellophane tape side.

The adhesion area increases as the thickness increases.

The lower limit of 1.50 OA for the sublayer N1 plating layer is
10- As the thickness decreases, the resistance value increases, causing uneven plating in the final electrolytic plating, which impedes the appearance quality of the final plating.0 Especially for Ag plating, black Nl plating, etc., which have poor throwing power. This tendency is remarkable in this case.

The features of the watch dial of the present invention are as follows: Firstly, display members with various surface finishes can be manufactured using the same device, as long as a resin mold is prepared, regardless of the pattern of the surface finish. Moreover, the process of curing the UV resin can be done in a short time υ, 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 of the present invention allows for an expanded variety of designs.

That is, 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 thermal polymerization using a casting method, and can be used repeatedly. As a result, many resin molds can be made. 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 in conventional methods of manufacturing timepiece dials due to restrictions in terms of man-hours can be realized with the method of 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 having a thickness of 20/100 ytrn. (3-■) In conventional dial manufacturing methods, the materials used for the base plate are limited to nickel silver and brass, but the material is specially tempered for use in 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 it is possible to significantly reduce the material cost of the base plate. . for example,
The nickel silver used in the conventional method costs 97 yen per sheet, but the steel material manufactured by the 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 10 at the part where the feet are attached (the amount of deformation is 1/100
~ 2/100 dragon protrusion), photosensitive resin will be formed on the surface of the base plate in the next process, so if it becomes a problem, it will be difficult.

Therefore, in the conventional manufacturing method, when attaching the fixed feet by resistance welding, it is necessary to smooth out the ridges formed on the base plate after welding, but in the manufacturing method of the present invention, There's no need for that.

Next, an appropriate amount of XFP700 photosensitive resin manufactured by Mukasei Co., Ltd. is dropped onto the base plate 1, and a CR-39 resin mold 3 with a desired surface pattern is placed on top of it.
A photosensitive resin monomer is sandwiched between the two to a thickness of 5/100 g. At this time, make sure that no air enters 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 upper knob. (3-@) The conditions for irradiating ultraviolet rays are UV with an intensity of 20 mW and curing occurs within a very short time within 30 inches.

The photosensitive resin used above has good releasability from the resin mold, good adhesion with the paste substrate, good adhesion with the metalized thin layer processed in the subsequent process, and good adhesion with the coating 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 such that it can be easily formed into a resin mold (for example, by thermal polymerization using a casting method), that it does not react with the photosensitive resin used, that it has good mold releasability from the cured photosensitive resin, and 3.
It is selected in consideration of its good transmittance of ultraviolet rays with wavelengths around 65 mm.

The method for manufacturing the resin mold will be described.

First, a master is made from metal, a resin for casting is poured between the metal master and the glass plate, and after it is thermally polymerized and hardened, 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 produce many resin molds from the first metal master.

In addition to CR-39, cast-type Aviv resin and transparent cast-type silicone rubber resin can be used as the resin mold of the present invention.

Next, when the base plate is peeled off from the resin mold after curing, 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 has been transferred. (6-■
) The adhesion between the photosensitive resin and the base plate can be improved by adding a material that has good adhesion to metal into the photosensitive resin.If you want to further improve the adhesion, After welding the fixed legs, apply an adhesive that has good adhesion to the metal with a cordon, and if the adhesive is not completely cured but reacts with the photosensitive resin, the adhesive strength will be perfect.

Next, ultraviolet rays (3
65 mm) to completely polymerize and cure the photosensitive resin. The irradiation conditions are an intensity of 20 mw.

Next, the surface of the photosensitive resin onto which the pattern has been transferred is subjected to metallization treatment.

(6-■) Wet plating and dry plating can be used as methods for metallization, but wet plating is preferable in terms of adhesion between the photosensitive resin and the metallized thin layer.

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

First, pretreatment is performed before plating. The pretreatment is
It is immersed in a tin chloride solution (1 chloride solution) for 1 minute, washed with water, immersed in a baladium chloride solution for 1 minute, washed with water, and then dried.

After the above pretreatment, plating is performed by immersion in electroless N1-P alloy plating (S-680 manufactured by Kanigen Co., Ltd.). Plating conditions are 50
°0,1 minute. N1-p layer under these conditions (P content 28%
) has a thickness of 500λ.

Next, electrolytic Nl plating is performed using a normal electrolytic plating method.

The thickness of the electroless N1-p alloy plating is as thin as possible within the range that allows the subsequent electrolytic NI plating, the better the adhesion between the photosensitive resin and the thin metal layer.

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

Next, electrolytic Ni plating is performed. The purpose of the sub-electrolytic Ni plating is to be necessary for the subsequent final electrolytic plating of Ag, Aμ, etc.

This is because finishing plating directly on the electroless Nl--P alloy plating is not possible due to problems in terms of coverage of the plating. The reason why the plating coverage of the final plating is poor is that electroless Ni--P alloy plating contains P, so its resistance value is 10 times higher than that of electrolytic NI plating, and that it is very thin.

Watt bath is preferable for electrolytic Ni plating in terms of plating coverage.

Composition 1 conditions for electrolytic Ni plating are as follows.

Nickel sulfate/L/6 hydrate 225 g/Nickel chloride 1V6 hydrate 40 g/-17-Boric acid 25 g/Brightener 7 g/t PH4,3 Liquid temperature 50°C Current density 1A/dze The thickness of electrolytic Nl plating under the above conditions is 3.000. The upper limit of 400 OA is limited by the plating adhesion between the photosensitive resin and the thin metal layer, and the lower limit of 1.50 OA is the thickness of the final plating. Limited in terms of gender.

Next, finish plating is performed. Types of finishing plating for the dial plate include Ag plating, Aμ plating, 9 black Ni plating, etc., and the plating thickness is preferably about 500λ as long as the color tone can be achieved.

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 above completed printing type dial plate, -18- When the adhesion test with cellophane tape was performed as described above, there was no development where the metal layer peeled off on the cellophane side, and the photosensitive resin and metal thin film were not developed. A dial plate with good layer adhesion can be obtained.

The above example is an example of a printing type dial plate with a surface pattern, but resin molds can also be made for dial plates with convex and concave shapes such as letters, windows, symbols, pictures, and marks. For example, it can be manufactured using the same method as in the above embodiment.

As described above, nine characters, windows, and marks were formed on the surface of the base substrate using the photosensitive resin and resin mold of the present invention.

The manufacturing method for watch dials, which is characterized by forming irregularities such as symbols and patterns and metallizing the surface, is a simple and single device that can efficiently manufacture dials with a variety of designs. This is possible, but it brings innovation to the manufacturing method of watch dials compared to the conventional method of manufacturing dials, which requires heavy equipment and requires multiple machines in the same process. .

In other words, the method for manufacturing watch dials of the present invention: ■ Can be unmanned with light equipment and a single line ■ Can handle small-volume production of a wide variety of products ■ Eliminates the need for heavy equipment ■ Significantly shortens manufacturing delivery time ■Reduction of factory space by a large amount ■Can accommodate diversification and expansion of designs and variety ■Reduction of indirect costs by simplifying logistics ■No longer requires high level of skill of workers.

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

[Brief explanation of the drawings] Figure 1 - ■ is a cross-sectional view of the manufacturing process of a conventional Patola finish type dial plate, and Figure 2 ■γ■ is a stamped weight type dial plate using the conventional pressing process. Cross-sectional view of the manufacturing process, Figure 6 ■
~■ are cross-sectional views showing the manufacturing process of timepiece characters according to the manufacturing method of the present invention. 1 is the base plate 2 is the fixed foot 3 is the paint layer 4 is the resin mold 5
6 indicates a photosensitive resin and a metalized thin layer. Applicant: Suwa Seikosha Co., Ltd. Representative Patent Attorney Tsutomu Mogami-21-

Claims (1)

[Scope of Claims] 1) Surface patterns, windows, symbols, patterns, marks, and other irregularities to be applied to a watch dial are molded onto the dial pace plate using a photosensitive resin and a resin mold, and the surface is made of metal. 2. A watch according to claim 1, characterized in that the surface of the photosensitive resin is provided with a metallized N1 plate. Method of manufacturing a dial plate.