JPS63126579A - Curing method for sealing material - Google Patents

Abstract

PURPOSE:To efficiently, quickly and easily cure a sealing material by locally heating a part where the sealing material is coated by the near IR rays emitted from a near IR heater disposed along the coating locus of the sealing material. CONSTITUTION:The near IR heater 4 is disposed apart at a distance from a work W along the coating locus of the sealing material 3 at the time of curing the sealing material 3 coated on the surface of the work W along the prescribed coating locus. the part where the sealing material 3 is coated is locally heated by the near IR rays emitted from said heater 4. As a result, the sealing material is quickly and easily cured with high efficiency without unnecessary heating and damaging of the other part. In addition, the easy temp. control is possible and various kinds of sealing materials can be cured by heating under the conditions optimum for said materials. The curing is easily executable without necessitating large-scale equipment.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for curing a sealant such as a sealer, a brimer, or a sealant such as IP+, which is applied to a body, etc. during the manufacturing process of an automobile. Used to harden sealants.

(Prior art and its problems) During the manufacturing process of automobiles, many types of sealants are used on the car body, but how to harden these sealants with the force 1 < important For example, in the first white body process (vehicle body assembly process), mastic adhesive, hemming adhesive, hemming sealer, spot weld sealer, etc. are applied, and then degreasing, chemical conversion treatment, and electrodeposition painting processes are applied. Through,
The sealant is heated and cured using the heat of baking the electrodeposition coating.

Further, the body sealer applied to the electrodeposited surface after electrodeposition baking is then subjected to intermediate coating, intermediate coating baking, top coating, and top coating baking steps, and is cured by the heat of the intermediate coating and top coating baking.

However, according to the conventional curing method described above, the sealant used in the first white body process suffers deformation due to deterioration due to the treatment liquid and damage in the shower between the time it is applied and the time it hardens. Otherwise, the components of the sealant may be eluted, causing deterioration of the processing liquid. Further, sealing materials used in the painting process do not deteriorate due to treatment liquids, etc., but there is a problem in that the sealing materials change in shape due to contact during the process.

To solve the above-mentioned problem, it would be better to heat and cure the applied sealant before it is influenced by the outside, but the following methods can be considered for this purpose:
The method of passing the sealant through the baking oven after applying the sealant requires the installation of a new baking oven, which clutters the equipment. There is a problem in that the rust preventive oil used in the process is sequestered, the paintability in subsequent processes is significantly reduced, and rust is generated due to the deteriorated rust preventive oil. Furthermore, in the method using high-frequency induction heating, heat is generated from the steel plate portion, so that local deterioration (annealing, etc.) of the steel plate occurs. Heating using electron beams or electromagnetic waves has the problem that the portion sandwiched between the steel plates is not heated, and all of these methods require large amounts of equipment. Although the method of blowing hot air does not require heavy equipment, it has problems in that the generated temperature is low, the efficiency is low, and the heat generating part lacks durability.

(Means for Solving the Problems) In view of the above-mentioned problems, the present invention provides a sealing material that can be incorporated into an automobile manufacturing process by heating and curing the sealing material without requiring any special equipment. The technical means for this purpose is a method of curing a sealing material applied along a predetermined coating trajectory on the surface of a material to be coated, and the near-infrared heater 4 is moved from the surface of the material to be coated. It is characterized in that it is arranged at a distance along the application locus of the sealant 3, and only the area where the sealant 3 is applied is locally heated by the near-infrared rays emitted from the near-infrared heater 4. This is a method of curing a sealant.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, workpieces W placed on pallets 2 are sequentially conveyed on an intermittent conveyor 1, and a station sealant S is used in a curing process to heat and harden the sealant.
It is positioned and stationary. Workpiece W is an automobile door made of sheet metal processed from a steel plate, on which a sealing material has been applied in a previous process along the folded edge of the upper surface in a substantially linear application trajectory. be.

Referring also to FIG. 3, above the sealing material 3 of the positioned workpiece W, there is a near-infrared heater 4 extending along the longitudinal direction of the sealing material 3 at a certain distance from the workpiece W.
is attached to a bracket 5 fixed to the frame of the conveyor 1 or the like. In the near-infrared heater 4, a reflecting mirror 7 whose surface is plated with gold is mounted inside a rectangular box-shaped case 6, and a rod-shaped near-infrared lamp 8 is attached to the focal position of the reflecting mirror 7. A glass window 9 is provided at the opening, and although not shown, an inlet/outlet for cooling water is provided on the outer surface of the case 6. This near-infrared heater 4 emits near-infrared rays from a near-infrared lamp 8 through an electric circuit to be described later, and the radiant energy is reflected downward by a reflector 7 to cover the sealing material 3 and the steel plate of the surrounding portion of the workpiece W. It is designed to heat locally.

In FIG. 4, the near-infrared lamp 8 is connected to an AC 200V power source via a bidirectional thyristor 9. The thermocouple 11 is installed so as to detect the ambient temperature near the sealing material 3, and after being amplified by the amplifying section 12, the thermocouple 11 is compared with the temperature set by the setting device 13 by the comparator 14. A voltage signal S1 corresponding to the difference between the temperature detected by the thermocouple 11 and the set temperature is output. This signal S1 is input to the comparator 15, compared with a triangular wave of a constant period, subjected to pulse width modulation, and the signal S1 is
The comparator 15 outputs a pulse signal S2 with an on-width corresponding to the magnitude of the signal S2. This pulse signal S2 is applied to the gate of the bidirectional thyristor 9, and a power supply voltage is applied to the near-infrared lamp only during the ON time of the pulse signal S2, thereby controlling the temperature.

According to the above embodiment, for example, when a PVC blastisol body sealer is used as the sealant 3, a near-infrared lamp 8 with an output of 980 W is used, and the distance between the sealant 3 and the near-infrared heater 4 is 10 m. The entire sealant 3 was cured in about 5 seconds. Also, the distance is 2Q
m, 40fi, 60m, 80tsuru, and 100M, 7 seconds, 11 seconds, 15 seconds, 20 seconds, respectively.
The whole was cured in 27 seconds. Therefore, with the workpiece W positioned as shown in FIGS. 1 and 2, the near-infrared heater 4 locally heats only the sealant 3 and the vicinity of the sealant 3, and the sealant 3 is heated in a short time. Can be hardened. Since the near-infrared heater 4 only needs to be installed in the station sealant S for the curing process, no special equipment is required and it can be installed immediately after the application process of applying the sealant 3. There is no possibility that the sealing material 3 will come into contact with other members and change its shape before it hardens, and the sealing material 3 and other processing liquids will not deteriorate during the process.

In the above-mentioned embodiment, an example was shown in which the sealing material 3 was applied to the upper surface of the workpiece W and hardened by heating, but as shown in FIG. The heating may be carried out through the steel plate of the workpiece W. Alternatively, as shown in FIG. In the above embodiment, an example was explained in which the seven near-infrared heaters 4 heated only one side of the workpiece W, but it is also possible to heat both sides (upper and lower surfaces) of the workpiece W using Jilt's near-infrared heaters 4. In this case, a bidirectional thyristor 9, a thermocouple 11, and a control section 10 may be provided for each near-infrared lamp 8 to perform temperature control. The position may be such that the near-infrared lamp 8, the sealing material 3, or the steel plate of the workpiece W is brought into contact to control the temperature, or an object having a specific heat similar to that of the sealing material 3 or the steel plate is attached to the thermocouple 11. The near-infrared heater 4 has been described as an example in which near-infrared rays are emitted in parallel; You can.

In the above embodiment, an example was explained in which the near-infrared heater 4 was fixed to the bracket 5, but it is also possible to attach the near-infrared heater 4 to the tip of the arm of the robot and move it to an appropriate position relative to the work W. You can also
Further, in the process of applying the sealant 3 to the workpiece W, the application may be performed by a robot, and a near-infrared heater 4 may be attached to the same robot to heat and harden immediately after application.

(Effects of the Invention) According to the present invention, since the sealing material or the vicinity of the sealing material can be locally heated and cured, other parts are not heated and damaged unnecessarily, and the efficiency is high. It can be easily cured in time. Since the sealant can be hardened by applying pressure directly or indirectly through the steel plate, it is easy to harden not only the surface of the steel plate, but also the back side of the steel plate and the sealant sandwiched between the ms. Can be hardened. In addition, temperature control can be easily carried out, and various sealing materials can be heated and cured under optimal conditions, and the process can be carried out easily without cluttering the equipment.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a plan view of the stationary run S for the curing process, Fig. 2 is a side view taken in the direction of the ■ arrow in Fig. 1, and Fig. 3 is an enlarged view of the main part of Fig. 2. 4 are circuit diagrams showing an example of a control circuit for a near-infrared lamp, and FIGS. 5 and 6 are side views showing other embodiments of the positions and shapes of the workpiece W and the sealant. 3... Sealing material, 4... Near-infrared heater, W.
...Workpiece (material to be coated). Applicant Sunstar Giken Co., Ltd. Figure 1 Figure 2121 Figure 3121 tjSJ Figure

Claims (1)

[Claims] A method for curing a sealant applied along a predetermined application trajectory on the surface of a material to be coated, the method comprising placing a near-infrared heater along the application trajectory of the sealant at a distance from the material to be coated. . A method for curing a sealant, characterized in that a portion to which the sealant is applied is locally heated by near-infrared rays emitted from the near-infrared heater.