[DESCRIPTION]
[invention Title] METHOD OF MANUFACTURING INTEGRATED CHANGABLE INSERT MOLDINGS FOR AUTOMOBILES [Technical Field] The present invention relates, in general, to methods of manufacturing integrated changeable insert moldings for automobiles and, more particularly, to a method of manufacturing an integrated changeable insert molding attached to a car body at a position above a door of an automobile.
[Background Art] Generally, a drip molding which is attached to a side portion of a car body at a position above a door as shown in FIG. 1 is a part which covers the gap between the door and the upper frame of the car body, thereby preventing the introduction of water and wind noise into the door and providing the automobile with a good appearance. A conventional drip molding for automobiles includes a drip rail front piece molding 101 and a drip rail rear piece molding 102, which are separately manufactured and are assembled together when they are attached to an automobile. The process of manufacturing the conventional drip rail front piece molding 101 includes twenty-seven steps, which will be briefly described hereinafter. The conventional drip rail front piece molding is manufactured by applying an adhesive on one surface of a c
stainless coil so as to facilitate attachment of polyvinyl chloride (PVC) to the stainless coil -> drying the adhesive- coated stainless coil -> roll-forming the stainless coil into a desired shape through twelve steps -> extruding PVC onto the adhesive-coated surface of the roll-formed stainless coil -> cooling the stainless coil -> cutting the stainless coil into desired moldings having a predetermined length -> stretch-bending each of the moldings according to the shape of a side frame of the car body so that the molding can be attached to the car body -> pressing the molding (including the steps of cutting the end of the molding' s front surface - > chamfering the molding' s end -> notching the molding -> cutt±ng the end of the molding' s rear surface) -> cutting, by means of a high-speed saw, the end portion of the molding at which, the molding is jointed to the drip rail rear piece mold±ng (102) -> applying an adhesive on a front end of the molding so as to finish the front end of the molding which is placed at the front side of the automobile -> insert- injection molding PVC onto the front end of the molding -> mounting a plurality of clips, which fasten the molding to the car body, to the inner surface of the drip rail front piece molding 101 (in this step, the clips have been separately manufactured through injection molding, and then finished prior to being mounted to the drip rail front piece molding 101) . In order to mount the drip rail front piece molding 101 manufactured through the above-mentioned process to the car body, a separate drip rail is manufactured and assembled with the drip rail front piece molding 101, and thereafter mounted to the car body through, for example, spot welding.
Because the conventional drip rail front piece molding 101 is manufactured through roll forming and extrusion, the drip rail is necessary for the attachment of the drip rail front piece molding 101 to the car body, and the process of mounting the drip rail to the car body is included in the process of manufacturing the car body. Further, the process of manufacturing the drip rail rear piece molding 102 includes twenty-one steps, which will be briefly described hereinafter. That is, the drip rail rear piece molding is manufactured through pressing a stainless coil into a desired molding shape -> attaching a protective tape onto the molding surface of the stainless coil (so as to prevent the surface from being scratched while being transported) -> removing the protective tape and ultrasonic-cleaning the molding surface - > drying the stainless coil -> applying an adhesive on the molding surface of the stainless coil in order to facilitate the attachment of PVC to the stainless coil when injection- molding PVC -> drying the adhesive-coated stainless coil -> secondarily applying an adhesive on the stainless coil in order to reinforce the attachment force -> drying the stainless coil -> high-frequency preheating the adhesive of the stainless coil using a high-frequency pre-heater -> inj ection-molding PVC onto the molding surface -> eliminating unnecessary injection gate and finishing -> attaching a protective tape -> mounting a plurality of clips to the drip rail rear piece molding using an assembly jig -> spot-welding a j oint portion of the drip rail rear piece molding which is aligned with the drip rail front piece molding when assembling the moldings together.
The drip rail rear piece molding manufactured in the above-mentioned process is mounted to the car body by inserting the clips, provided on the inner surface of the drip rail rear piece molding 102, into assembly holes formed on the car body. As described above, the conventional drip molding for automobiles includes two separate moldings which are manufactured through a complicated method including two different ways of molding, insert-press molding and roll forming molding. Therefore, not only are the manufacturing costs increased, but also wind noise may be generated and the external appearance of the automobile may deteriorate due to a possible gap between the two moldings. Moreover, there is a high possibility that foreign materials may be caught in the gap when the automobile is washed (especially by an automatic car-wash machine) . Further, while the drip rail front piece molding 101 is manufactured by roll-forming a stainless coil and extruding PVC onto the surface of the roll-formed stainless coil, the drip rail rear piece molding 102 is manufactured by pressing a stainless coil and injection-molding PVC onto the surface of the pressed stainless coil. Therefore, the surfaces of the two moldings may have different colors due to the difference in the ways of forming the stainless coils and the difference in the ways of processing PVC, namely, protrusion and injection-molding. Furthermore, in order to attach the drip rail front piece molding 101 to the car body, a drip rail must be separately manufactured and mounted to the car body through spot welding, which further complicates the process. In an effort to overcome the above-mentioned problems
occurring in the conventional drip molding for automobiles which includes two separate molding pieces, the inventor of the present invention proposed, in Korean Patent No. 268836 (entitled "Integrated changeable insert molding for an automobile and manufacturing method thereof") , a method of manufacturing an integrated drip molding for automobiles, into which separate conventional molding pieces manufactured hitherto in various ways are incorporated, and which is integrally manufactured using a unified single manufacturing procedure including insert-injection molding and pressing. The method of manufacturing the integrated drip molding for automobiles will be briefly described herein below. That is, the integrated drip molding is manufactured through pressing a stainless coil, to one surface of which an adhesive has been applied and to the other surface of which a protective tape has been attached, into an integrated coil body having a shape corresponding to a desired integrated drip molding, this step corresponding to a blanking step using a general press -> slightly bending opposite edges of the pressed flat stainless coil, this step corresponding to a general press-forming step -> placing the stainless coil to which the adhesive has been applied in an injection mold, and firstly insert-inj ection molding the stainless coil so that a polypropylene resin layer is formed on the inner surface of the stainless coil, wherein the injection mold has a molding shape capable of forming a plurality of clips integrally with the polypropylene resin layer, the shapes of the clips can be formed by means of a slide core of a general injection mold, and the stainless coil and the polypropylene resin layer are integrated together by the adhesive applied on the inner
surface of the stainless coil, which is melted at a high temperature (about 200°C to 240°C) of the injection-molded material (polypropylene resin) , and the material used herein may be a polypropylene resin containing glass fiber or talc, or a polypropylene resin containing elastomer (including natural or synthetic rubber) -> inserting the product, one surface of which has been first injection-molded with the polypropylene resin, into a second injection mold and secondly inj ection-molding the product to form a second injection-molded portion, wherein the molding material used in the second injection-molding process is a polypropylene resin of the same group as the polypropylene resin used in the first injection-molding process, because the materials of the same group can be easily integrated with each other due to the injection heat and their integration provides a strong integration force even without separately applying adhesive (in this case, the integration signifies integration between polypropylene resin and polypropylene resin) -> subjecting the integrated product to a finishing process, so that an integrated drip molding is manufactured. In consideration of the characteristics of the product, the material used in the first injection molding should be hard. Therefore, it is preferred that a polypropylene resin to which a reinforcement material, such as glass fiber, has been added be employed in the first injection molding. In contrast, the material used in the second injection molding should feel soft so that it is preferred that a polypropylene resin to which a soft material, such as natural or synthetic rubber, has been added be employed in the second injection molding. The integrated drip molding manufactured through the
above-mentioned, method includes a stainless coil, opposite edges of which are somewhat bent (by press-forming) , with a first polypropylene resin layer formed on one surface of the stainless coil, a plurality of clips integrally formed on the surface along the longitudinal direction of the first polypropylene resin layer, and second polypropylene resin layers covering portions of the first polypropylene resin layer and the stainless coil other than both ends and exposed portions thereof. Therefore, the integrated drip molding can be assembled with a car body by inserting the clips into a plurality of assembly holes formed through the car body. Therefore, the integrated drip molding manufactured through the above-mentioned method has one integrated body and is manufactured through a simplified method which includes only pressing and insert-injection molding.
Further, the clips for mounting the drip molding to the car body need not be separately prepared and assembled with the molding but ca be formed to be integrated with the molding. However, the above-mentioned conventional method of manufacturing the integrated changeable insert molding must include two insert-injection molding steps which are the first insert-injection molding step of seating (inserting) a stainless coil in an injection mold and forming the integrated body of the molding along with the clips, and the second insert-injection molding step of forming a soft lip along an edge of the integrated body of the molding. Thus, the method including the two insert-injection molding steps is somewhat complicated and increases the manufacturing costs of the drip moldings for automobiles.
[Disclosure] [Technical Problem] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method of manufacturing integrated changeable insert moldings for automobiles, which includes only one insert- injection molding process, thus simplifying the process of manufacturing the moldings compared to conventional methods .
[Technical Solution] In order to accomplish the above object, the present invention provides a method of manufacturing an integrated changeable insert molding which is attached to a car body at a predetermined position above a door of an automobile, the method comprising: press-blanking a stainless coil into a predetermined shape; press-forming opposite edges of the stainless coil and bending the opposite edges of the stainless coil at acute angles by striking the edges of the stainless coil using an inclined surface of a punch, thus providing locking edges; and seating the stainless coil in a mold and injecting a melted synthetic resin into the mold, thus forming a molding body made of the synthetic resin to be integrated with the stainless coil through an insert-injection molding process, in which the locking edges of the stainless coil are embedded in the molding body and a plurality of locking bosses made of a material identical to the material of the molding body is formed to be integrated with the molding body through the insert-
injection molding process such that the locking bosses are arranged along a longitudinal direction of the molding body and are separated by predetermined intervals. To accomplish the above object, the present invention also provides a method of manufacturing an integrated changeable insert molding which is attached to a car body at a predetermined position above a door of an automobile, the method comprising: press-blanking a stainless coil into a predetermined shape; press-forming opposite edges of the stainless coil and bending the opposite edges of the stainless coil at acute angles by striking the edges of the stainless coil using an inclined surface of a punch, thus providing locking edges; and seating the stainless coil and a plurality of separately manufactured locking bosses in a mold such that the locking bosses are arranged along a longitudinal direction on a surface of the stainless coil and are separated by predetermined intervals, and injecting a melted synthetic resin into the mold, thus integrally forming a molding body made of the synthetic resin on an inside of the stainless coil through an insert-injection molding process, in which the locking edges of the stainless coil and parts of the locking bosses are embedded in the molding body. To accomplish the above object, the present invention further provides a method of manufacturing an integrated changeable insert molding which is attached to a car body at a predetermined position above a door of an automobile, the method comprising: press-blanking a stainless coil into a predetermined shape, the stainless coil having an adhesive applied to a surface thereof; . press-forming
opposite edges of the stainless coil, thus bending the opposite edges of the stainless coil at predetermined angles such that the adhesive-coated surface of the stainless coil is concave; and seating the stainless coil in a mold and injecting a melted synthetic resin into the mold, thus forming a molding body made of the synthetic resin to be integrated with the stainless coil through an insert-injection molding process, in which a plurality of locking bosses made of a material identical to the material of the molding body is formed to be integrated with the molding body through the insert-injection molding process such that the locking bosses are arranged along a longitudinal direction of the molding body and are separated by predetermined intervals. To accomplish the above object, the present invention further provides a method of manufacturing an integrated changeable insert molding which is attached to a car body at a predetermined position above a door of an automobile, the method comprising: press-blanking a stainless coil into a predetermined shape, the stainless coil having an adhesive applied to a surface thereof; press-forming opposite edges of the stainless coil, thus bending the opposite edges of the stainless coil at predetermined angles such that the adhesive-coated surface of the stainless coil is concave; and seating the stainless coil and a plurality of separately manufactured locking bosses in a mold such that the locking bosses are arranged along a longitudinal direction on a surface of the stainless coil and are separated by predetermined intervals, and injecting a melted synthetic resin into the mold, thus integrally
forming a molding body made of the synthetic resin on an inside of the stainless coil through an insert-injection molding process, in which parts of the locking bosses are embedded in the molding body. In the method of the present invention, the locking bosses may be clips which are locked to holes formed on the car body. Further, the synthetic resin may be a soft synthetic resin prepared by mixing polyolefin and polyamide . Further, the adhesive may be prepared by mixing polyester as a main component and polyisocianate as a hardening agent.
[Description of Drawings] Herein below, the method of manufacturing integrated changeable insert moldings for automobiles according to the present invention will be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a view illustrating an automobile having a conventional drip molding comprising two molding pieces; FIG. 2 is a view illustrating an automobile having an integrated changeable insert molding manufactured through a method of the present invention; FIG. 3 is a sectional view taken along the line III-
III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the first embodiment of the present invention; FIG. 4 is a sectional view illustrating an attachment of the integrated changeable insert molding of FIG. 3 to a
car body; FIG. 5 is a sectional view taken along the line III-
III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the second embodiment of the present invention; FIG. 6 is a sectional view taken along the line III-
III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the third embodiment of the present invention; and FIG. 7 is a sectional view taken along the line III-
III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the fourth embodiment of the present invention.
[Best Mode] FIG. 2 is a view illustrating an automobile having an integrated changeable insert molding manufactured through the method of the present invention. As shown in the drawing, the integrated changeable insert molding for automobiles manufactured through the method of the present invention comprises a single body which is formed through a molding process so that a drip rail front piece molding part 1 and a drip rail rear piece molding part 2 are integrally formed as parts of the single body. However, it should be understood that the drip rail front piece molding part 1 and the drip rail rear piece molding part 2 may be separately manufactured and, thereafter, integrated into a single body
at the ends thereof without affecting the function of the present invention. FIG. 3 is a sectional view taken along the line III- III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the first embodiment of the present invention. As shown in the drawing, the integrated changeable insert molding manufactured through the method according to the first embodiment of the present invention comprises a stainless coil 10 which is formed into a predetermined shape through pressing, a molding body 20 which is formed in a predetermined shape using a synthetic resin through injection molding so that the molding body 20 is integrated with the stainless coil 10 at a position inside the coil 10, and a plurality of locking bosses 30 which are provided along a surface of the molding body 20 as shown in FIG. 4 so that the bosses 30 protrude from the molding body 20 and are separated by predetermined intervals. The locking bosses 30 are inserted into a plurality of assembly holes formed on a car body, thus locking the molding to the car body 5. The reference numeral 3 in FIG. 4 denotes a seal pad which is tightly interposed between the molding body 20 and the car body 5 to prevent noise and water from being introduced into the car body 5. In the present invention, the molding body 20 and the locking bosses 30 may be integrally formed as a single body through injection molding. Further, in the first embodiment, the bosses 30 are shaped as clips 30 which can be locked to the car body 5. However, the locking bosses of the present invention may be shaped as clip support bosses
30b to support clips as shown in FIG. 6 which illustrates an integrated changeable insert molding manufactured through a method according to the third embodiment of the present invention. Further, opposite edges of the stainless coil 10 are bent at acute angles by striking the edges of the stainless coil 10 using an inclined surface of a punch, thus providing locking edges 11. During the insert- injection molding process of forming the molding body 20 to be integrated with the stainless coil 10, the locking edges 11 are embedded in the molding body 20, thus firmly integrating the molding body 20 with the stainless coil 10. Due to the locking edges 11 of the stainless coil 10, the molding body 20 is not likely to be deformed by twisting or bending although the body 20 is made only of a soft synthetic resin through the insert-injection molding process. Therefore, unlike the conventional complicated process of manufacturing the integrated changeable insert molding, in which the molding body is formed of a hard synthetic resin through a first insert-injection molding process and, thereafter, a lip 21 is formed of a soft synthetic resin along the edge of the molding body through a second insert-injection molding process, the method according to the present invention provides an integrated changeable insert molding having the same quality as that of the conventional integrated changeable insert molding by integrally forming the molding body 20 with the lip 21 provided along the edge of the body 20 using only a soft synthetic resin and an insert—injection molding process. FIG. 5 is a sectional view taken along the line III- III of FIG. 2, which illustrates the construction of an
integrated changeable insert molding manufactured through a method according to the second embodiment of the present invention. As shown in the drawing, the integrated changeable insert molding for automobiles manufactured by the method according to the second embodiment of the present invention is different from the molding manufactured by the method according to the first embodiment as follows. In the first embodiment, the locking bosses 30 are formed to be integrated with the molding body 20 through an insert-injection molding process. However, in the second embodiment, locking bosses 30a are previously manufactured, and, thereafter, the bosses 30a are seated as inserts in an injection mold at predetermined positions. Thereafter, the molding body 20 is formed through insert- injection molding so that parts of the locking bosses 30a are embedded in the molding body 20, thus being integrated with the molding body 20. In a detailed description, the previously manufactured locking bosses 30a are seated in an insert-injection mold such that the bosses 30a are arranged along a surface of the stainless coil 10 and are separated by predetermined intervals . Thereafter, a melted synthetic resin is injected into the mold, thus forming the molding body 20 on the inside of the stainless coil 10 through insert-injection molding. During the insert-injection molding process, parts of the locking bosses 30a are embedded in the molding body 20 so that the bosses 30a are integrated with the molding body 20. In the second embodiment, the locking bosses 30a are shaped as separately manufactured clips 30a which can be locked to a car body. However, the locking bosses may be shaped as separately
manufactured bolts instead of separately manufactured clips 30a. Further, the locking bosses may be shaped as separately manufactured clip support bosses to support clips as shown in FIG. 6, which illustrates the integrated changeable insert molding manufactured through the method according to the third embodiment of the present invention. FIG. 7 is a sectional view taken along the line III- III of FIG. 2, which illustrates the construction of an integrated changeable insert molding manufactured through a method according to the fourth embodiment of the present invention. In the fourth embodiment of the present invention, the opposite edges of the stainless coil 10 are not bent at acute angles, therefore, the stainless coil 10 does not have locking edges 11, unlike the stainless coil 10 of the first embodiment. However, the stainless coil 10 having a predetermined thickness is produced through a press- blanking process and is, thereafter, subjected to a press- forming process in which opposite edges of the stainless coil 10 are appropriately bent such that an adhesive-coated surface of the coil 10 is concave. Thereafter, an insert- injection molding process is carried out to form a molding body 20 to be integrated with the coil 10 using only a soft synthetic resin. During the insert-injection molding process, the stainless coil 10 and the molding body 20 are firmly integrated into a single body, so that the integrated changeable insert molding of the present invention is not likely to be deformed by twisting or bending. In the fourth embodiment, locking bosses 30 are shaped as clips 30 which can be locked to a car body. However, the locking bosses 30 may be shaped as clip support bosses 30b to support clips as
shown in FIG. 6 which illustrates the integrated changeable insert molding manufactured through the method according to the third embodiment of the present invention. Further, in the fourth embodiment, the locking bosses 30 are shaped as clips 30 which are formed to be integrated with the molding body 20 through the injection molding process. However, in the same manner as that described for the second embodiment, the locking bosses 30 may be formed by inserting separately manufactured clips 30a in an insert-injection mold and by executing an insert-injection molding process to form a molding body 20 with parts of the separately manufactured clips 30a embedded in the molding body 20 so that the clips 30a are integrated with the molding body 20. In the above case, the locking bosses 30 may be shaped as separately manufactured bolts or separately manufactured clip support bosses to support clips. In the integrated changeable insert molding manufactured by the method of the present invention, the lip 21 which is in direct contact with the paint-coated surface of a car body is formed to be integrated with the molding body 20. Thus, unlike the conventional method in which a second insert-injection molding process should be executed to form the lip 21 on the molding body, the method of the present invention forms the lip 21 to be integrated with the molding body through the first insert-injection molding process. Therefore, the synthetic resin used in the insert- injection molding process of the present method is selected from soft synthetic resins which feel soft and are highly elastic and not likely to be thermally deformed, and have high corrosion resistance. Examples of soft synthetic resins
are polyvinyl chloride (PVC) , thermoplastic polyurethane (TPϋ) , thermoplastic rubber (TPR) , rubber, and synthetic resin prepared by mixing polyolefin and polyamide. In the method according to the present invention using an adhesive 40 on a designated surface of the stainless coil, the adhesive 40 may be selected from conventionally used industrial adhesives. However, it is preferred to use an adhesive prepared by mixing polyester as a main component and polyisocianate as a hardening agent. In the above-mentioned embodiments, when the locking bosses are formed to be integrated with the molding body through an insert-injection molding process, the locking bosses are shaped as clips 30. However, the locking bosses in the above state may be shaped as clip support bosses 30b instead of as clips. Further, in the above-mentioned embodiments, when the locking bosses are separately manufactured and used as inserts along with the stainless coil 10 in an insert-injection mold, the locking bosses are shaped as separately manufactured clips 30a. However, the locking bosses in the above state may be shaped as separately manufactured bolts instead of separately manufactured clips. As described above, the present invention provides a method of manufacturing integrated changeable insert moldings for automobiles, which includes only one insert- injection molding process, and simplifies the process of manufacturing the moldings compared to conventional methods .