JPS6144197A - Drying furnace for pretreatment for coating by electrodeposition - Google Patents

Abstract

PURPOSE:To prevent a degreasing liq. and a soln. for chemical conversion treatment sticking to a hanger from scattering and sticking to the surface of a degreased and washed article to be coated when the article is dried in a drying furnace, by placing a cover member between the upper part of the hanger and the article. CONSTITUTION:An article 3 to be coated is suspended with a hanger 5 and pretreated by degreasing, chemical conversion treatment and washing. The pretreated article 3 is put in a drying furnace 1 with an overhead conveyor 6, and hot air is blown from blowing nozzles 2 to dry the article 3. At this time, a cover member 8 isolating the upper part of the hanger 5 from the article 3 is attached beforehand to the inside of the side wall 1a of the furnace 1 so as to prevent a degreasing liq. and a soln. for chemical conversion treatment remaining on the upper part of the hanger 5 from scattering and sticking to the surface of the article 3. Thus, the article 3 can be coated uniformly by electrodeposition in the following stage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drying oven for pretreatment in electrodeposition coating.

(Prior art) Generally, the automotive painting process includes pre-treatment, undercoating, intermediate coating,
It consists of four basic processes for topcoating.

Among these basic steps, the pretreatment step is carried out according to the flow note shown in Figure 3, and its purpose is to completely remove oils adhering to the car body (hereinafter referred to as the object to be coated) transported from the car body shop. By forming a chemically stable inorganic film on the surface of the steel plate (film chemical conversion treatment), it inactivates the plate surface, provides rust prevention, and prevents the coating from adhering to the plate. It's about helping sex. Here, in the degreasing treatment, an alkaline degreasing liquid containing sodium phosphate or the like is used, and in the film chemical conversion treatment, a chemical conversion liquid containing zinc phosphate or the like is used.

(Problems to be Solved by the Invention) In this pre-treatment step, since the object to be coated is normally transported on a hanger, the degreasing liquid and chemical solution attached to the top of the hanger may remain. Due to his deafness, he had to enter the drying oven used in the final process, the draining and drying process, and the degreasing liquid and chemical liquid remaining on the top of the hanger would scatter and adhere to the surface of the coated object. When the next step, electrodeposition coating, is applied to such a deaf object, there is a problem in that the deposited area becomes sticky, causing a defective coating, which has become a major problem that needs to be solved.

In view of the above-mentioned problems, the present invention aims to prevent degreasing liquid or chemical conversion liquid from adhering to the surface of a coated object in a drying oven.

(Means for solving the problems) The present invention provides, as a means for solving the above problems,
A drying oven is used to wash and dry the object that has undergone the surface treatment process as a pretreatment for electrodeposition coating, and has a hanger for hanging the object from one side, and the hanger is moved inside the drying oven. and a cover member having a cover part that is attached to a fixing part of the apparatus in the drying oven and shields between the upper part of the hanger and the workpiece during movement. It is characterized by

(Function) In the present invention, the above means, that is, the means of shielding between the upper part of the hanger and the object to be coated, prevents the degreasing liquid or chemical solution remaining on the upper part of the hanger from adhering to the surface of the object to be coated. The effect of prevention can be obtained.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

This drying oven 1 is installed at the end of the pretreatment process, and the workpiece 3 passing through the interior is heated by hot air from hot air outlets 2.2 provided on the inner surface of the side walls 1a, Ia. It acts like draining and drying the car body (specifically, the car body).

The object to be coated 3 is dried in a drying oven, and pre-treated by conventional methods, ie, degreased with a degreasing solution containing sodium phosphate, etc., coated with a chemical solution containing zinc phosphate, etc., and washed with water. has been done. During this n:i treatment step, the object to be coated 3 is conveyed by the same object conveying device 4 from beginning to end.

The object conveying device W4 is composed of a hanger 5 having a C-shape when viewed from the conveying direction, and an overheight conveyor 6 for moving the hanger 5. Reference numeral 7 is a rail for guiding the conveyor. .

The hanger 5 has a C-shape so that the object 3 to be coated can be hung from one side.

The hanger 5 is attached to the inner surface of the side wall 1a facing the open end of the hanger 5 in the drying oven 1.
A cover member 8 having an opening-shaped cross section is attached to the cover member 8, which has a cover portion that shields the space between the upper part of the hanger 5 and the VT coating material 3 when passing through the inside. In other words, the object 3 to be coated is held by the cover member 8 while passing through the drying oven l.

By configuring as described above, if the degreasing liquid or the chemical solution remains on the upper part of the hanger 5 and is transported into the drying oven 1, the degreasing liquid or the chemical solution will be applied to the surface of the vI coating material 3 in the drying oven l. can completely prevent adhesion.

Note that a heat panel can also be used as the cover member 8.

(Effects of the Invention) As described above, according to the present invention, since the space between the upper part of the hanger and the object to be coated is shielded with the cover member in the drying oven, the processing liquid (degreasing liquid) remaining on the hanger can be removed. If the liquid (chemical liquid or chemical liquid) is scattered, it will be shielded by the cover member, preventing the treatment liquid from adhering to the object to be coated, and as a result, preventing the occurrence of bumps during the next step, electrodeposition painting. It has the excellent effect of preventing

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing a drying oven for pretreatment in electrodeposition coating according to an embodiment of the present invention, and FIG. 2'' is a perspective view showing the relationship between the hanger and the cover member in the drying oven of FIG. 1. , Fig. 3 is a flow note showing a general surface treatment process. 1...Drying oven 3...Workpiece 4...Workpiece conveyance device 5...・Hanger 6...Overhead conveyor 8...Cover member/ , drying furnace 3, material q, material transfer device 5: hanger 2: overhead conveyor 8: cover member

Claims (1)

[Claims] 1. A drying oven for washing and drying the object to be coated after the surface treatment step as pre-treatment for electrodeposition coating, which has a hanger for hanging the object from one side and dries the hanger. a cover member that is attached to a device fixing part in the drying oven and has a cover part that shields between the upper part of the hanger and the workpiece during movement; A drying oven for pretreatment in electrodeposition coating, characterized by comprising: