Manufacturing method of nose pad support member for eyeglasses by metal powder injection molding

Abstract

To provide a manufacturing method which integrally manufactures a nose pad support member composed of a hook part, a connection part and a support part of spectacles by metal powder injection molding.SOLUTION: A method for manufacturing a nose pad support member of spectacles by metal powder injection molding that manufactures a nose pad support member composed of a hook part, a connection part and a support part of spectacles by metal powder injection molding includes the steps of: mixing 55 to 65 vol.% of stainless steel powder and 35 to 45 vol.% of a binder, and manufacturing a feed stock; injecting the manufactured feed stock to a mold of a nose pad support member of spectacles using an injection molding machine, and thereby molding a molding; defatting a binder of the manufactured molding by a catalyst; and sintering the defatted molding.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a nose pad support member for spectacles by metal powder injection molding, and more particularly to a method for manufacturing a nose pad support member for spectacles, which comprises a hook portion, a connecting portion, and a support portion, as a single unit by metal powder injection molding. [Background technology]

[0002] In recent years, with the increasing use of computers and mobile phones, the number of people with poor eyesight is increasing, and the demand for glasses is also increasing. Also, more and more people are wearing glasses as a fashion statement.

[0003] If a part of the glasses breaks during use, you will have to buy a new pair or have them repaired. Rational consumption, where you replace only the broken part when your glasses break, has become mainstream.

[0004] The nose pad support member of spectacles is provided on the inside rear of the lens support portion of the spectacles frame and contacts both parts of the bridge of the nose of the spectacles wearer, thereby ensuring stable wearing of the spectacles.

[0005] Some eyeglass nose pad support members have support parts provided on both sides behind the eyeglass frame fixing part, while others have only one support part provided behind the eyeglass frame fixing part.

[0006] The one having a pair of support parts is provided only one between a pair of lens support parts of the eyeglass frame, and the other having one support part is provided inside each of the lens support parts.

[0007] Nose pad support members for eyeglasses come in various shapes depending on the material and design of the eyeglass frame.

[0008] In the case of a plastic eyeglass frame, the plastic eyeglass nose pad support member may be injection molded integrally with the eyeglass frame, or a separate plastic eyeglass nose pad support member may be removably attached to the eyeglass frame.

[0009] The present invention particularly relates to a nose pad support member for eyeglasses which is disassembled and attached to a plastic eyeglass frame and has a support portion behind a fixing portion of the eyeglass frame.

[0010] Metal Injection Molding (MIM) is a technology that can mass-produce precision parts with complex 3D shapes without post-processing. Metal powder is mixed with a binder, a thermoplastic polymer material, to create a moldable mixture, which is then molded.

[0011] The molded metal injection body is degreased and the binder is removed, and then sintered at high temperature in a specific atmosphere to produce products with precise dimensions and complex shapes. This manufacturing method allows for mass production with low equipment costs even if the product shape or material is changed. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Republic of Korea Patent Publication No. 10-1156068 [Patent Document 2] Republic of Korea Patent Publication No. 10-2010-0091756 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention relates to a method for manufacturing a nose pad support member for eyeglasses by metal powder injection molding, and more specifically, to a method for manufacturing a nose pad support member for eyeglasses consisting of a hook portion, a connecting portion, and a support portion as a single unit by metal powder injection molding. [Means for solving the problem]

[0014] A manufacturing method for a nose pad support member for eyeglasses by metal powder injection molding according to one embodiment of the present invention is characterized by including the steps of: mixing 55 to 65 volume % stainless steel powder and 35 to 45 volume % binder to manufacture a feedstock; molding a molded body by injecting the manufactured feedstock into a mold for a nose pad support member for eyeglasses using an injection molding machine; catalytically degreasing the binder of the manufactured molded body; and sintering the degreasing molded body.

[0015] The hook portion 100 of the nose pad support member of the eyeglasses is provided with an elastic fixing portion 110 at the front and an insertion support portion 120 at the rear, and the elastic fixing portion 110 is cylindrical with chamfered sides.

[0016] The elastic fixing part 110 has a notched groove 111 formed horizontally at the center of its tip, and a tapered adhesion part 112 having a large diameter at its tip and a small diameter at its rear end is provided at its front, and anti-rotation ribs 113 are provided at the rear center of both side surfaces of the elastic fixing part 110.

[0017] The insertion support part 120 provided at the rear of the elastic fixing part 110 is cylindrical and has a diameter larger than the diameter of the rear end of the elastic fixing part 110 .

[0018] The stainless steel powder accounts for 55 to 65% by volume of the 100% by volume of the feedstock, and the stainless steel powder is a spherical powder having a particle size D50 of 6 to 8 μm.

[0019] Of the binder (100% by volume), 60 to 75% by volume of polyoxymethylene (POM); From carnauba wax or paraffin wax One or more selected waxes 5-15% by volume, polycarbonate (PC), polypropylene (PP) or Polyethylene (PE) from The composition is characterized by comprising 10 to 25 volume % of one or more selected polymers and 5 to 15 volume % of a surfactant.

[0020] The present invention is characterized in that stainless steel powder and a binder are placed in a dedicated kneader and kneaded under pressure and heat to produce a pellet-shaped feedstock.

[0021] The heating is characterized in that the stainless steel powder and the binder are kneaded under pressure at a temperature 10 to 20° C. higher than the temperature at which the binder can be melted in the kneading step of the stainless steel powder and the binder.

[0022] The injection speed in the molding step is characterized by being 120 to 128 mms. The degreasing process is characterized in that the product is loaded into an oven maintained at 100 to 130°C, concentrated nitric acid at 90°C or higher is supplied at 1 to 10 ml / min, and nitrogen gas is supplied at 1 to 5 l / min for 4 to 8 hours to remove the binder.

[0023] The sintering step is performed using stainless steel powder Within the temperature range where it does not melt The method is characterized by sintering the mixture at a temperature of 1330 to 1360°C in a hydrogen (H2) atmosphere for 2 to 3 hours.

[0024] In the sintering step, the sintered plate is made of high-purity alumina (Al2O3) with an alumina content of 90% or more, and the roughness of the sintered plate is in the range of Ra 0.5 to 1.0 μm. Effect of the Invention

[0025] In the present invention, stainless steel powder and a binder are mixed to form a green body, which is then degreased and sintered to manufacture an eyeglass nose pad support member consisting of a hook portion, a connecting portion, and a support portion as a single unit. This minimizes the processing steps required after pressing the eyeglass nose pad support member to create grooves, protrusions, chamfered corners, tapered portions, etc., and enables the manufacture of elongated eyeglass nose pad support members in a single metal powder injection molding process, thereby reducing material waste and enabling mass production.

[0026] The nose pad support member for eyeglasses manufactured according to the present invention has an end face of the connecting part connecting the hook part and the support part that is smaller and circular than the hook part and the support part, thereby enabling the connecting part connecting the hook part and the support part of the nose pad support member for eyeglasses to bend into the shape desired by the wearer so that the eyeglasses can be worn according to the shape of the wearer's nose and their preferences. [Brief description of the drawings]

[0027] [Figure 1] 1 is a perspective view of a nose pad support member for eyeglasses manufactured by the manufacturing method of the present invention. [Diagram 2] 1 is a front view of a nose pad support member for eyeglasses manufactured by the manufacturing method of the present invention. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] 3 is a cross-sectional view of FIG. 2 taken along line B-B. [Diagram 5] FIG. 2 is an exploded rear perspective view of a nose pad support member and a spectacle frame of the eyeglasses according to the present invention. [Figure 6] 4 is a flowchart showing a method for manufacturing a nose pad support member for eyeglasses according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, a specific example of a method for manufacturing a nose pad support member for glasses by metal powder injection molding according to the present invention will be described in detail. Also, in describing the present invention, detailed descriptions of related well-known general configurations or functions will be omitted.

[0029] Hereinafter, the terms "upper", "lower", "forward", "rearward" and other directional terms will be defined with reference to states defined in the specification.

[0030] Figure 1 is an oblique view of a nose pad support member for eyeglasses manufactured using the manufacturing method of the present invention, Figure 2 is a front view of the nose pad support member for eyeglasses manufactured using the manufacturing method of the present invention, Figure 3 is a cross-sectional view along AA in Figure 1, Figure 4 is a cross-sectional view along BB in Figure 2, and Figure 5 is a rear exploded oblique view of the nose pad support member for eyeglasses and eyeglass frame of the present invention.

[0031] The shape of the nose pad support member of the eyeglasses manufactured by the manufacturing method of the present invention and the structure and state of connection with the eyeglass frame will be described below.

[0032] As shown in Figures 1 and 2, the nose pad support member for glasses according to a preferred embodiment of the present invention is composed of a hook portion 100, a connecting portion 200, and a support portion 300, all of which are manufactured by a single metal powder injection molding process.

[0033] The hook portion 100 of the nose pad support member for eyeglasses of the present invention is inserted into the hook portion insertion groove of the eyeglass frame 400 and is coupled with the eyeglass frame 400 .

[0034] In the nose pad support member for eyeglasses, a hook portion 100 is provided with an elastic fixing portion 110 at the front and an insertion support portion 120 at the rear.

[0035] The elastic fixing portion 110 of the hook portion 100 is cylindrical with chamfered sides.

[0036] In addition, the elastic fixing part 110 has a notched groove 111 formed horizontally in the center of the tip, and a tapered adhesion part 112 having a large diameter at the tip and a small diameter at the rear end is provided in the front, and an anti-rotation rib 113 is provided in the rear center of both side surfaces of the elastic fixing part 110.

[0037] The insertion support portion 120 provided behind the elastic fixing portion 110 is cylindrical and has a diameter larger than the diameter of the rear end of the elastic fixing portion 110 .

[0038] In addition, it is preferable that the connector 200 has an elastic restoring force against a small external load while maintaining the deformed state when artificial force is applied to the nose pad support member of the eyeglasses so that the eyeglasses can be worn according to the shape of the wearer's nose and the wearer's preference. In the present invention, the end surface of the connector is manufactured in a circular shape.

[0039] A support portion 300 is formed behind the connecting portion 200 by being bent downward.

[0040] The support 300 has a pad connection hole 310 at its lower end for fixing a pad (not shown) made of silicon material.

[0041] The conventional manufacturing method for the nose pad support member of the above-mentioned eyeglasses involves punching out the outer shape consisting of the hook portion 100, connecting portion 200, and support portion 300 using a press, and then forming the hook portion by cutting or by a method such as die casting.

[0042] The press and cutting methods require complicated manufacturing processes and high manufacturing costs, and manufacturing processes using casting such as die casting have difficulty in meeting the dimensional tolerances of the hook portion.

[0043] In order to solve the problems of the conventional manufacturing methods, the present inventors have invented a manufacturing process for metal powder injection molding.

[0044] The joining structure and joining state of the nose pad support member of the eyeglasses and the eyeglass frame manufactured according to the present invention will be described with reference to the rear exploded perspective view of the nose pad support member of the eyeglasses and the eyeglass frame in FIG.

[0045] As shown in FIG. 3, the nose pad support members of the eyeglasses are removably attached to an eyeglass frame 400 made of a plastic material.

[0046] The eyeglass frame 400 to which the eyeglass nose pad support member is attached has insertion grooves 430 on both sides of the rear surface of a connecting portion 420 provided between a pair of lens support portions 410 so that the hook portions 100 can be inserted therein.

[0047] The internal structure of the insertion groove 430 of the eyeglass frame 400 must correspond to that of the hook portion 100 .

[0048] The insertion grooves 430 formed on both sides of the rear surface of the connecting part 420 of the eyeglass frame 400 must have elastic fixing parts (not provided) corresponding to the elastic fixing parts 110 of the hook part 100 at their inner front parts.

[0049] Also, an insertion support portion (not shown) corresponding to the insertion support portion 120 of the hook portion 100 must be provided at the inner rear portion of the insertion groove 430 .

[0050] Also, an insertion protrusion (not shown) must be provided at the inner lower end of the insertion groove 430 so as to correspond to the notch groove 111 of the hook portion 100 in the lateral direction.

[0051] Therefore, the elastic fixing portion (not shown) of the insertion groove 430 of the eyeglass frame 400 is cylindrical with chamfered sides.

[0052] In addition, the insertion groove 430 of the eyeglass frame 400 has a tapered contact portion (not shown) at the front, which has a large diameter at the tip and a small diameter at the rear end, and a rib insertion groove (not shown) is provided at the rear center of both sides.

[0053] Further, the insertion support portion (not shown) provided behind the elastic fixing portion (not shown) of the insertion groove 430 of the eyeglass frame 400 is cylindrical with a diameter larger than the diameter of the rear end of the elastic fixing portion (not shown).

[0054] The nose pad support member for the glasses can be easily assembled with the glasses frame 400 by simply inserting the hook portion 100 into the insertion groove 430 provided in the connection portion 420 of the glasses frame 400 at the rear of the glasses frame 400.

[0055] In the assembled state of the nose pad support member for eyeglasses according to the preferred embodiment of the present invention and the eyeglass frame 400, the notch groove 113 of the hook portion 100 is inserted into the insertion protrusion (not shown) of the eyeglass frame insertion groove 430.

[0056] Also, the contact portion 112 at the front of the elastic fixing portion 110 is tightly contacted with the contact portion (not shown) of the eyeglass frame insertion groove 430 .

[0057] Therefore, unless a strong external force is applied, there is no risk of the nose pad support members of the eyeglasses coming off the eyeglass frame 400.

[0058] Also, the rotation prevention rib 113 of the hook portion 100 is inserted into a rib insertion groove (not shown) of the insertion groove 430 of the eyeglass frame 400 to form a +-shaped connection.

[0059] There is no risk of the hook portion 100 and the connecting portion 200 rotating in the left-right direction, and a solid assembled state can be maintained.

[0060] On the other hand, when disassembling the nose pad support members of the assembled eyeglasses, the connecting portion 200 provided integrally with the rear of the hook portion 100 is grasped and pulled strongly toward the rear of the eyeglass frame 400.

[0061] Then, the hook portion 100 is pulled out from the insertion groove 430 of the eyeglass frame 400, so that the nose pad support member of the eyeglasses can be easily disassembled from the eyeglass frame 400.

[0062] During the process of disassembling the eyeglass nose pad support member, when the hook portion 100 is pulled out of the insertion groove 430 of the eyeglass nose pad support member 400, the upper and lower portions of the contact portion 112 of the hook portion 100 narrow toward the cutout groove 111 and come out of the contact portion (not shown) of the eyeglass frame insertion groove 430.

[0063] In this manner, the nose pad support member of the eyeglasses according to a preferred embodiment of the present invention can be easily assembled and separated from the eyeglass frame 400, and therefore can be easily repaired or replaced if damaged.

[0064] In addition, if the wearer has nose pad support members of various designs, they can be changed to match the eyeglass frame 400 or to suit the wearer's psychological state and preferences, thereby expressing the wearer's individuality.

[0065] FIG. 4 is a flow chart showing a method for manufacturing a nose pad support member for eyeglasses according to the present invention.

[0066] The manufacturing method of the nose pad support member of the present invention includes the steps of manufacturing a feedstock by mixing 55 to 65 volume % stainless steel powder and 35 to 45 volume % binder, molding a molded body by injecting the manufactured feedstock into a mold for the nose pad support member of the eyeglasses using an injection molding machine, catalytically degreasing the binder of the manufactured molded body, and sintering the degreased molded body.

[0067] Of the 100% by volume of the feedstock, the stainless steel powder accounts for 55 to 65% by volume, and the stainless steel powder used is a spherical powder having a particle size D50 of 6 to 8 μm.

[0068] The binder is composed of polyoxymethylene (POM), which is the main binder that maintains shape and allows flow, waxes that reduce the viscosity of the feedstock and promote lubrication with the mold, and surfactants that improve the wetting and adhesion of powder and polymer.

[0069] The binder is 100% by volume, of which 60 to 75% by volume is polyoxymethylene (POM), 5 to 15% by volume of wax selected from the group including carnauba wax and paraffin wax, 10 to 25% by volume of polymer selected from the group including polycarbonate (PC), polypropylene (PP), and polyethylene (PE), and 5 to 15% by volume of surfactant.

[0070] Stainless steel powder and a binder consisting of polyoxymethylene (POM), one or more waxes selected from the group including carnauba wax and paraffin wax, one or more polymers selected from the group including polycarbonate (PC), polypropylene (PP), and polyethylene (PE), and a surfactant are placed in a dedicated kneader and kneaded under pressure and heat to produce a pellet-shaped feedstock.

[0071] At this time, the mixture is kneaded under pressure at a temperature 10 to 20° C. higher than the temperature at which the binder is melted in the kneading process of the stainless steel powder and the binder.

[0072] The pellet-shaped feedstock thus produced is used to produce a molded product using an injector. Since the shape of the nose pad support member of the eyeglasses of the present invention is thin compared to its length, it is difficult to fill the molded product, so the molded product is injected at a speed of 120-128 mm / s, which is 10-25% faster than the general injection speed, to ensure smooth filling up to the end of the mold, and 5-15% by volume of wax selected from the group including carnauba wax and paraffin wax is added to the binder components to increase the fluidity.

[0073] It is important that the binder is removed while maintaining the shape of the compact in the debinding process. The products are loaded into an oven whose internal temperature is maintained at 100-130°C, and concentrated nitric acid of 90% or more is supplied at 1-10 ml / min, while nitrogen gas is supplied at 1-5 l / min for 4-8 hours.

[0074] In the sintering step, the stainless steel powder undergoes transient liquid phase sintering to produce a high density sintered body with a sintered density of 95-98% from the porous degreased body. The sintering step is performed by maintaining the temperature range of 1330-1360℃ in a hydrogen (H2) atmosphere for 2-3 hours, within the temperature range where the stainless steel powder melts but does not melt.

[0075] The hydrogen (H2) gas atmosphere in the sintering step removes the oxide film of the raw powder generated during the manufacturing process by reacting it with hydrogen, and also removes the carbon component, which is a residual binder component, thereby increasing the sintered density of the stainless steel during the sintering process.

[0076] The shape of the nose pad support member of the eyeglasses of the present invention is thin compared to its length and has a small cross-sectional area, so it is important to control it so that it shrinks uniformly when sintered. In addition, by controlling the roughness of the sintered plate used for sintering, the shrinkage during sintering is uniform. The sintered plate is high-purity alumina (Al2O3) with an alumina content of 90% or more, and the roughness of the sintered plate is in the range of Ra0.5 to 1.0 μm.

[0077] Although specific parts of the present invention have been described in detail above, for those skilled in the art, such specific techniques are merely preferred embodiments, and the scope of the present invention is not limited thereby. Therefore, the true scope of the invention should be defined by the appended claims and their equivalents. [Explanation of symbols]

[0078] 100: Hook part 110: Elastic fixing part 111: Notched groove 112: Contact part 113: Anti-rotation rib 120: Insertion support part 200: Connection part 300: Support part 400: Eyeglass frame 410: Lens support 420: Connection part 430: Hook part insertion groove

Claims

1. In manufacturing a nose pad support member for spectacles, which comprises a hook portion, a connecting portion, and a support portion, by metal powder injection molding, preparing a feedstock by mixing 55-65 volume percent stainless steel powder and 35-45 volume percent binder; A step of molding a molded body by injecting the produced feedstock into a mold for a nose pad support member of spectacles using an injection molding machine; A step of catalytically degreasing the binder of the produced compact; and sintering the degreased compact. The sintering step of sintering the degreased compact includes the steps of: A sintered plate is used, which is made of high-purity alumina (Al 2 O 3) with an alumina content of 90% or more and has a roughness in the range of R a 0.5 to 1.0 μm. The step of sintering the degreased compact includes: A method for manufacturing a nose pad support member for eyeglasses by metal powder injection molding, characterized in that sintering is performed by maintaining a temperature range of 1330 to 1360°C in a hydrogen atmosphere for 2 to 3 hours, within a temperature range in which stainless steel powder does not melt.

2. The method for manufacturing a nose pad support member for eyeglasses by metal powder injection molding as described in claim 1, characterized in that the binder is composed of 60 to 75 volume % polyoxymethylene, 5 to 15 volume % wax selected from one or more of carnauba wax and paraffin wax, 10 to 25 volume % polymer selected from one or more of polycarbonate, polypropylene and polyethylene, and 5 to 15 volume % surfactant, out of 100 volume % of the binder.

3. The method for manufacturing an eyeglass nose pad support member by metal powder injection molding as described in claim 1, characterized in that the degreasing process involves loading the product into an oven maintained at 100 to 130°C, supplying concentrated nitric acid at 90°C or higher at 1 to 10 ml / min, and supplying nitrogen gas at 1 to 5 l / min for 4 to 8 hours to remove the binder.

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