JPH03242914A - Method of coating electronic part with resin - Google Patents

Abstract

PURPOSE:To remove the resin projections of the base ends of leads by flattening the bottom face of a resin armor by pressurization from the lead tips while the resin is viscous during semi-hardening. CONSTITUTION:After powder coating of thermosetting resin, the resin is uniformly pressurized in the direction of the base ends from the tips of leads while the resin is viscous during semi-hardening to flatten the bottom face of a resin armor. That is, the resin is molded while viscous during semihardening, therefore, the bottom face of the resin armor can be flattened by pressurization from the lead tips with appropriate jigs 20A and 20B. The resin is hardened by regular hardening without resin drop with its bottom face kept flat. Thereby electronic parts can be soldered to a substrate perpendicularly in a good soldering state without imperfect soldering.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a resin packaging method for electronic components having leads.

[Conventional technology]

The exterior of a resin-clad electronic component such as a capacitor is usually made by placing a heated element in fluidized powder resin, causing the powder resin to adhere to the element using the heat, and then heating and curing the resin.

FIG. 3 shows the above steps. Attach the lead tip to the support tape and apply powder coating under heating.

The powder is a powdered thermosetting resin, and when the resin is applied to the element surface by fluidized dip coating or electrostatic spray coating, the resin becomes semi-hardened by heat.

At the base of the reed, resin drips and swells near the root (base end). Next, the tip of the resin that is attached to the lead is cut off and then cured.

However, cutting the sagging portion does not completely remove the resin adhering to the lead. Therefore, in the final product manufactured by curing, residual resin remains as convex spherical protrusions.

[Problem to be solved by the invention]

The spherical protrusion at the base end of the lead as described above causes various problems when mounted on a board. Figure 2 (al~(C
Each of the disadvantages will be explained in Section 1, and the electronic components of the conventional example are shown on the left side of each of the figures (al to (C)).

Note that the right side shows that the disadvantages of conventional products are solved with respect to the electronic component of the embodiment of the present invention.

Now, to explain the conventional product, as shown in Fig. 2(a), when soldering to the board 1, due to the shape of the resin protrusion of the lead, the board 1 and the protrusion only make line contact at the inner periphery. As a result, the contact becomes unstable and is fixed at an angle, often resulting in contact with other parts 3 in the vicinity. Other parts 3
If the case is made of metal, the contact occurs through a thin resin film, which may cause problems in terms of withstand voltage.

As shown in Figure 2 fb), the resin protrusion of the lead is
If it gets into the through hole 2, the solder will not go well and the soldering will be defective. In order to prevent the failure accidents mentioned in (a) and (b) above, the second part is bent near the tip of the lead.
The method shown in Figure (e) may be used. However, this has the disadvantage that the height of the parts increases when they are mounted.

An object of the present invention is to provide a resin sheathing method that eliminates the above-mentioned drawbacks and completely eliminates the resin protrusion at the base end of the lead.

[Means to solve the problem]

In the present invention, after powder coating the thermosetting resin except for the tip of the lead of the electronic component, and before the main curing process of the resin, the resin is applied from the tip of the lead to the proximal end in a semi-cured viscous state. Apply pressure uniformly in the direction of the parts so that the bottom of the resin exterior is molded into a flat shape.

[Effect]

Since the resin is molded in a semi-cured and viscous state, the bottom surface of the resin sheath can be made into a flat shape by applying pressure to the resin from the base end of the lead using an appropriate jig. If the main curing is performed in this manner, there will be no dripping of the resin, and the bottom surface of the resin will be cured with a flat shape.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 illustrates the embodiment in the order of the process.

(PI) is a process in which the tip of the lead is attached to the support tape 10 to hold the electronic component, and powder coating is performed.

In this example, the liquid immersion coating method is used, but the temperature of the electronic parts is set to 90°C, for example, and powdered thermosetting resin is applied.
By using a material with a softening temperature lower than that, the resin is fused and adhered to the entire surface except for the lead tips (P2). After powder coating, electronic parts are further heated to 80℃ for primary curing.
Store at 110°C for 0.5 to 1 hour. Molding is carried out immediately after powder coating or while it is in a semi-cured state during primary curing. That is, the required molding is performed while the resin is in a semi-cured, viscous state, which facilitates resin molding. (
P3゜P4) shows an example of the molding method, in which the resin-free part of the lead tip is inserted into the lead guard 21 of the upper jig 2゜A and the lower jig 20B, and then <P3> and the jig 20A are inserted.
, 20B, and fix the jig 20 as shown in (P4).
Alternatively, move the electronic component and apply pressure to the resin at the base end of the lead. At this time, since resin 1 is viscous, (P
As shown in 5>, the resin bottom surface is molded flat. Therefore, the resin is completely cured by performing secondary curing (main curing) at 90°C to 135°C for 1 to 2 hours.At this time, the bottom of the resin is flat and the resin is tightly molded. The shape does not deteriorate due to curing.After secondary curing (P6)
The product can be separated from the support tape 1o as shown in FIG.

〔Effect of the invention〕

In the resin coating according to the present invention, as shown in FIG. 1 (P6), the resin bottom surface is flat, and the leads directly protrude from this flat surface without resin dripping.

Therefore, as shown in Fig. 2+al fbl (C1 shows the actual height measurement of the present invention on the right side in correspondence with the conventional product on the left side), all the drawbacks of the conventional method can be eliminated. It is possible to solder without tilting perpendicularly to the board.Also, as shown in (b), the solder rises well during soldering and no solder defects occur.Furthermore,
Since it is not necessary to use the conventional method of bending the leads and separating them from the board for soldering, the height of the mounted component 6 can be minimized.

[Brief explanation of drawings]

Fig. 1 is a diagram sequentially showing the process of an embodiment of the present invention, Fig. 2 is a diagram for comparing and explaining problems when mounting a conventional product and a product of the present invention on a board, and Fig. 3 1 is a diagram showing a conventional process. 1 - board, 2 - through hole, 10 - support tape, 20° 20A. 0B jig.

Claims (1)

[Claims] After powder coating the thermosetting resin except for the lead tips of electronic components, and before the main curing process of the resin, in a semi-cured viscous state, apply the resin uniformly from the lead tips towards the proximal end. A resin exterior packaging method characterized by applying pressure to form the bottom of the resin exterior into a flat shape.