KR100380851B1 - Replace Mig Metal Welding Procedure of Automotive assemble line chemical resin - Google Patents

Abstract

The present invention relates to the MIG welding process in the automobile manufacturing line. More specifically, when assembling the vehicle, spot welding of the pillar of the pillar between the ROOF and the side plate of the body is performed. The present invention relates to a system capable of significantly shortening the working time and manpower of a MIG welding process by filling a connection space between a steel frame and a steel frame with a synthetic resin after the spot welding.

The MIG welding process of the present invention for achieving the above object is to replace the conventional metal filler (FILLER) by filling a synthetic resin filler in the connection space and rapidly curing by induction vulcanization, etc. It is supposed to grind the part and go through the painting work process.

Description

Replace Mig Metal Welding Procedure of Automotive assemble line chemical resin}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MIG welding process of an automobile pillar in an automobile manufacturing line, and more particularly, to a connection space (that is, an assembly tolerance portion) between a steel frame for a vehicle and a steel frame. The present invention relates to a mig welding method of an automobile pillar portion using a synthetic filler, which can significantly reduce the work time and manpower required for the mig welding process of the automotive pillar portion.

An automobile manufactured by assembling numerous parts can be largely divided into a body and a chassis according to its main components. Here, the vehicle body is a portion for carrying a person or cargo, and corresponds to the outer shell of the vehicle. The shape varies according to the purpose of use such as a passenger car, a bus, a van, etc. In general, a vehicle body (or a steel frame) for a passenger car is composed of a car compartment, an engine room, a trunk, and the like as shown in FIG.

In recent years, when the vehicle is overturned, a monocoque body (monocoque body or frameless body) having a strong and light structure is integrally formed with the roof, the side plate, and the bottom of the body to increase safety. Monocoque car bodies are manufactured by welding several sheets of steel sheets or surface treated steel sheets.

1 shows a structural diagram of a steel frame for a general automobile, in which the A-pillar (A), B-pillar (B), and C-pillar (C) portions, which are steel plate connection portions of the steel frame 1 (car body), are shown by arrows. do.

FIG. 2 is a cross-sectional view of a welded portion filled with bronze or brazing after welding the connection spaces of the A-filler, B-pillar and C-pillar portions of FIG. 1 by the MIG welding method of a conventional automobile pillar portion, and FIG. In the MIG welding method of the automobile pillar portion of the present invention, a filling state diagram of the connection space between the steel frame and the steel frame is shown. As can be seen from FIGS. 2 and 3, the conventional MIG welding method of the automobile pillar portion is made of steel. After the mig spot welding between the frame and the steel frame, for example, the connection space 2 of the A pillar, the B pillar, and the C pillar region with a conventional MIG torch, the connection space 2 is made of metal filler ( 3), i.e., after filling by melting bronze or hard lead, and then filling the protruding portion of the filler protruding from the virtual contour when the outer circumferential surface of the steel frames are successively (not shown) It is completed by grinding to do).

By the way, in the case of the conventional MIG welding method of the automobile pillar portion as described above, the welding process itself is primarily completed within a few seconds to several tens of seconds, but is used to grind or polish the gushing portion of the metal filler 3. In some cases, depending on the vehicle model to be worked on, it takes a short time from 15 minutes to 40 minutes. For example, in the case of a 9-seater van or light vehicle, a tack time of about 19 to 20 minutes (Mig 1st: 13 minutes, Mig 2nd: 6 minutes) from mig welding to completion of the polishing operation This takes On the other hand, a large vehicle with a displacement of 3,000 cc or more has a width of 300 mm or more for the C-pillar (C) in order to ensure safety, and thus, a total of about 40 minutes is required for the welding time and the polishing time.

In addition, when the metal filler 3, for example, bronze or braze is melted to fill the connection space 2 between the steel frame and the steel frame, the braze is melted and filled at a temperature of about 1000 ° C. As a result, the temperature of the steel frame, which is made of steel, almost reaches an Al transformation temperature (about 723 ° C.). In the actual field, the fillers A, B, and C are shown as shown in FIG. 3 to secure the speed of the filling operation. Since a hole is drilled in the steel sheet on the inside of the room installed inside, and the cooling air is blown to the back of the filling part through the inside, the structure of the steel frame is deformed due to a sudden temperature change, and thermal stress is latent in this part. When the vehicle shipped in this state travels on an uneven road surface, cracks are generated on the painted surface of the connection space 2 side or cracks are generated on the steel frame. There was a problem that could lead to accidents.

In addition, since fine metal dust is generated when grinding or grinding the filler portion protruding out of the imaginary contour lined around the outer circumferential surface of the steel frames, six people are placed on the left and right sides of the production vehicle in the MIG welding line, thereby polishing work. In reality, even if the workers work while wearing a dust-proof mechanism, such as a dust mask, some of the dust may accumulate in the lungs through the airway of the worker there was also a problem that is very likely to cause industrial disasters.

Fig. 4 shows a process flow diagram according to a mig welding method of a conventional automobile pillar part in an automobile manufacturing line. As referred to in Fig. 4, a conventional automobile manufacturing line is a process from a mig welding process to an assembly completion process. There are a large number, each working process time is long, and the number of people involved in each process (about 20 to 25 people) is also very large, there was an economic problem.

Accordingly, the present invention has been made to improve the problem of the conventional MIG welding method of the automobile pillar portion as described above, it can significantly reduce the number of processes compared to the conventional MIG welding method of the automobile pillar portion, in particular polishing work Improved MIG of car pillars, which can reduce the number of people involved in the process by more than 50%, significantly reduce the time required for each process, and also reduce industrial accidents by improving the working environment An object of the present invention is to propose a welding method.

As a result of repeated studies to achieve the above object, when using a metal filler, there are some differences depending on the material of the filler, but the breakthrough process time or industrial accident prevention to be provided in the present invention is never As a result, in the MIG welding method of the automobile pillar part according to the present invention, the polishing work with the greatest number of workers and long working time is performed among the respective working steps constituting the MIG welding process. Emphasis was placed on improving the process.

Therefore, the above task can be easily made by filling the connection space between the steel frame using a synthetic resin filler such as epoxy instead of a metal filler such as bronze or braze that has been used in the conventional MIG welding method of the automobile pillar portion. As such, it can be achieved by a MIG welding method of the automobile pillar part according to the present invention.

1 is a structural diagram of a typical automotive steel frame,

FIG. 2 is a cross-sectional view of a welded part filled with a metal filler after welding the connection spaces of the A-filler, B-pillar, and C-pillar parts of FIG. 1 according to a conventional MIG welding method of an automobile pillar part; FIG.

3 is a diagram illustrating a filling state of a connection space between a steel frame and a steel frame in a conventional MIG welding method of a vehicle pillar portion;

4 is a process flowchart according to a mig welding method of a conventional automobile pillar portion in an automobile manufacturing line,

5 is a process flowchart by a mig welding method of an automobile pillar portion according to the present invention in an automobile manufacturing line;

6 is a schematic explanatory diagram of a resin curing method of a synthetic resin filler in a MIG welding method of an automobile pillar portion according to the present invention;

7 is a distribution chart of the amount of shock delivered when a vehicle collides with the front face.

Explanation of symbols on the main parts of the drawings

1: steel frame

2: connection space

3: metal filler

4: synthetic resin filler

5: MIG spot weld

6: conductive adhesive

7: inductor

A: A filler

B: B filler

C: C filler

H: magnetic field

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the MIG welding method of the automobile pillar portion according to the present invention using a synthetic resin filler.

FIG. 5 is a process flowchart showing a work process from a MIG welding process to an assembly completion process in an automobile manufacturing line proposed in the present invention, and FIG. 6 is a method of MIG welding of an automobile pillar part according to the present invention. Fig. 5 is a schematic explanatory view of a resin curing method of a synthetic resin filler. As shown in Fig. 5, the MIG welding method of an automobile pillar portion according to the present invention is performed by MIG spot welding of both ends of a steel frame and a steel frame of an automobile. After that, the filler is filled and hardened in the connection space 2 between the MIG spot welds 5, and then the automobile pillar portion for polishing the brushed portion protruding from the virtual outline connecting the outer circumferential surfaces of the steel frames 1 to each other. In the MIG welding method, a synthetic resin filler (5) is used as the filler, and the synthetic resin filler (4) is induction vulcanized. (Induction cure method) characterized in that the rapid curing for 10 seconds to 20 seconds at a temperature of 130 to 190 ℃ or less, and then the surface is ground with sand paper. Comparing the mig welding process line with the mig welding process line of the conventional automobile pillar part shown in FIG. 3, the work process after a finishing work process is the same, but the previous work process is different from each other. That is, in the conventional MIG welding method of the automobile pillar portion, the connection spaces between the steel frames are spot welded at both ends by the MIG torch, and then a metal filler is formed in the empty connection space 2 between these MIG spot welds 5. (3) is melted and filled, and then the filler (3) filled in the liquid phase is hardened by the grinding machine to add the extra portion added than necessary, and then transferred to another process, the automobile pillar portion according to the present invention The MIG welding method is a method of filling a synthetic resin filler (4) instead of a metal filler (3) and rapidly hardening it, and then polishing a part that deviates from the ideal outline of the steel frame for automobiles. The reason why it is possible to substitute synthetic resin instead of metal is that filler is not related to the rigidity and safety of the vehicle. This is because it is a factor related to the property. For example, as shown in FIG. 7 showing a distribution diagram of the amount of shock delivered when the vehicle collides in the front, the total amount of impact when the vehicle collides in the front is regarded as 100. At this time, the total of the impact shocks received by the A-pillars (A), B-pillars (B), and C-pillars (C) is insignificant to about 5, and most of the impact shocks are borne by the mig spot weld 5 on the A-pillar side. In other words, each of the pillars A, B and C maintains the rigidity of the vehicle body by the MIG spot weld 5 and fills the filler filled in the connection space 2 between the steel frame and the steel frame of the automobile pillar portion. Since the exterior of the finished car is secured, the material of the filler can be changed and used. As in the MIG welding method of the automobile pillar portion according to the present invention, a synthetic resin filler is used to make the steel frame and the steel frame. In the case of filling the connection space 2 between them, the synthetic resin filler 4 should not be shrunk after hardening above all, and even if large bubbles are generated inside the hardened layer of the synthetic resin filler 5. Can not be done. In addition, the surface of the cured layer of the synthetic resin filler 4 must be coated in a subsequent process, so electrodeposition should be possible. However, the filler should not exceed the size of the chip generated during polishing operation up to 100 μm. . This is because, if the size of the abrasive chip of the filler exceeds 100 µm, light scattering occurs on the surface of the coating even if it is hardly recognized by the naked eye, resulting in loss of value as a commodity. Therefore, to date, metal fillers such as bronze or brazing are used, and the size of chips must be limited even when grinding the bristle parts of such metal fillers, so only sand papers of # 150 to # 220 are used. In the MIG welding method of the automobile pillar part which concerns on this invention, the schematic explanatory drawing of the resin hardening method of the synthetic resin filler is shown.

The synthetic resin filler 4 used in the MIG welding method of the automobile pillar portion according to the present invention may be cured by an induction vulcanization method or a curing method using a heating oven, as shown in FIGS. 5 and 6. It is preferable to heat and harden for 10 second at the temperature of C-190 degreeC. In particular, when the induction vulcanization method is adopted as the curing method, the periphery of the connection space 2 should be thoroughly cleaned with a solvent (MEK or heptane).

Here, reference numeral 6, which is not described, is a conductive adherend, 7 is an inductor (electromagnet), and H represents a magnetic field.

And in the MIG welding method of the automobile pillar portion according to the present invention, when curing the synthetic resin filler, it is important not to increase the curing temperature to 190 ℃ or more, if heated to 190 ℃ or more, the heat of curing of the synthetic resin itself Therefore, the actual internal temperature of the synthetic resin is 210 ° C or more, which causes carbonization in the synthetic resin layer, thereby lowering the adhesive strength to the steel frame and worsening the environment inside the synthetic resin layer. In addition to this, if the resin filler cannot be completely cured, burrs are generated on the surface of the cured synthetic resin during the polishing operation, so that the resin filler 4 must be completely cured.

Meanwhile, the synthetic resin filler 4 used in the MIG welding method of the automobile pillar portion according to the present invention is preferably an epoxy resin of a solid component. In addition, the synthetic resin filler 4 should have electrical conductivity to enable electrostatic coating, Edo must have thixotropy to prevent resin from flowing down, and must have impact resistance to prevent falling from steel frame (car body). In addition, the synthetic resin filler 4 should have the performance shown in Table 1 below.

The synthetic resin filler 4 exhibiting the above-mentioned performance may be composed of components such as, for example, a bisphenol A type epoxy resin, a DICY type latent curing agent, a conductive carbon black, and a conductive inorganic filler. The mixture is prepared by stirring for about 30 minutes under a pressure of 0.7 bar and vacuum conditions up to 40 ° C.

Table 2 below is a process sequence table showing the tack time and process contents of each work process in the MIG welding method of the automobile pillar according to the present invention, about 6 minutes (only the work process from process 1 to process 6 is collected) As a result, productivity is dramatically improved compared to the conventional MIG welding method of the automobile pillar portion, which requires a tack time of 15 minutes to 40 minutes.

The reduction of the tack time is expected to bring about a process improvement effect of several tens of trillion won in view of the domestic industry that ships one vehicle every 30 seconds to one minute.

Therefore, when the MIG welding method of the automobile pillar portion according to the present invention as described above is applied to the automobile production line, the work time and personnel can be reduced by 70% or more, and the straightness of the automobile manufacturing line can be reduced by reducing the defective rate. By rethinking inventory, productivity can be dramatically increased and car manufacturing costs can be drastically reduced. In addition, since there is no harm to the health of workers and safety accidents can be prevented in advance, there is an excellent effect of reducing industrial accidents.

Claims (5)

MIG spot welding the steel frame of the automobile and both ends of the steel frame, filling the connection space 2 between the MIG spot welds 5 and hardening them, and then connecting the outer peripheral surfaces of the steel frames 1 In the MIG welding method of the automobile pillar part which grinds the toothed part of the pillar which protrudes from an outline, As the filler, a synthetic resin filler (5) is used, and the synthetic resin filler (4) is rapidly cured for 10 seconds to 20 seconds at a temperature of 130 ° C to 190 ° C by induction vulcanization, and then the surface is sandpaper. MIG welding method of the automobile pillar part using the synthetic resin filler characterized by grind | polishing by the resin. The method of claim 1, The synthetic resin filler (4) is Mig welding method of the automobile pillar portion using a synthetic resin filler, characterized in that the epoxy resin. The method of claim 2, The synthetic resin filler 4 is prepared by stirring bisphenol A type epoxy resin, DICY type latent curing agent, conductive carbon black, and conductive inorganic filler under a pressure of 0.7 bar and a vacuum condition of 40 ° C. or less for about 30 minutes. The MIG welding method of the automobile pillar part using the synthetic resin filler made into. After mig spot welding the connection space 2 between the steel frame and both ends of the steel frame, the filler is filled and cured in the connection space 2 and then protruded from a virtual contour connecting the outer circumferential surfaces of the steel frames 1. In the MIG welding method of the automobile pillar portion, which polishes the toothed portion of the filler to be made, MIG welding method for automobile pillar parts using a synthetic filler filler, characterized in that a synthetic filler is used as the filler, and the synthetic resin filler is cured using a curing oven, and then the surface thereof is ground with sand paper. . delete