JP2902890B2 - Molding method for irregular shaped parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method capable of forming a plurality of types of molded parts with a single mold.

[0002]

2. Description of the Related Art Conventionally, when a light emitting diode (hereinafter, referred to as an LED) is mounted on a substrate using a mounting tool such as a holder, a method of mounting the LED 3 after mounting the holder 2 on the substrate 1 (see FIG. 6). And a method of attaching the LED 4 to the substrate 1 and then attaching the holder 5 (see FIG. 7). In this case, two types of holders, that is, the holder 2 having the locking rib 2a formed thereon and the holder 5 having no locking rib are required. The terminals 3a and 3b of the LED 3 are
It is formed into a long and short length for manual insertion into the substrate 1. The LED 4 in FIG. 7 has a terminal portion 4a bent as shown for automatic insertion by an automatic machine.
It is attached to the tape 6.

As another method, there is a method in which a tongue piece 7a is provided on a holder 7, as shown in FIGS. FIG.
In the case of (1), if the tongue piece 7a is formed so that the tongue piece 7a is broken by the mounting operation of the holder 7 after the LED 4 is mounted on the substrate 1, It can be used for both manual insertion and automatic insertion.

[0004]

In the above method, the former case requires two types of molds, which is uneconomical. In the latter case, the tongue pieces become chips and require a removal operation.

[0005]

According to a first aspect of the present invention, an engaging film portion is formed on a mold butt portion formed of a resin material having good fluidity by a mold having a gas vent portion provided on an inner surface butt portion of a cylindrical part. A plurality of types of irregularly shaped parts are formed by a molding method for obtaining a first part to be formed or a second part in which a locking film portion is not formed at the mold butting portion formed of a normal resin material. .

[0006]

When the LED is to be inserted after the holder is attached to the substrate when mounting the LED, the holder having no locking film portion is made to correspond to the LED, and after the holder is attached to the substrate, the LE is inserted.
When D is inserted, it is possible to cope with automation and manual insertion by using two types of holders formed by a single molding die by associating the holder with the locking film portion.

[0007]

1 is a plan view and a sectional view of a first part of the present invention, FIG. 2 is a plan view and a sectional view of a second part, FIG. 3 is a flow characteristic diagram of a resin material, and FIG. FIG. 5 is a plan view and a partial cross-sectional view of the degassing portion, and FIG.

In FIG. 1 and FIG. 2, the holder 11 is integrally formed with a light-shielding cylindrical portion 11a, a mounting foot 11b, a locking claw 11c, and a locking film portion 12. The holder 13 in FIG. 2 is not provided with the locking film 12. If used,
After attaching the holder 11 to the substrate 1, the LED 3 (not shown) is inserted. Alternatively, when the LED is automatically inserted into the substrate by an automatic machine, the holder 13 on which the locking film 12 is not formed is inserted. In addition, 13a is a step part which engages with the LED3.

As a method of molding the above two types of holders 11 and 13 from a single mold, a difference in fluidity of a resin material is basically used to form a thin film on the abutting surface of the same mold. Is caused to be formed. Specifically, on the butting surface of the mold on which the locking film portion 12 is formed,
A gap is provided as a gas release clearance described later. The gap is slightly different depending on the resin material.
It may be about 03 to 0.05 mm. The holder 11 on which the locking film portion 12 is formed is formed by using a resin material having good fluidity, and the holder 13 without the locking film portion 12 is obtained by using a resin material having low flowability. Can be

According to the Denka ABS physical properties table shown in Table 1,
Even in the same material, the melt flow index value representing the fluidity of the resin material is 8 to 54.7 (g / 10 minutes).
Is very different.

[0011]

[Table 1]

FIG. 3 is a graph showing the flow characteristics of the resin, showing the relationship between the temperature and the spiral flow length. As shown in Table 2, the spiral flow length is a trade name of polycarbonate (PC) A2500 and a trade name PC obtained by mixing ABS (acrylic butadiene styrene) with PC.
The spiral flow length of the alloy polymer SC-250 is 25 cm for the former and 60 cm for the latter, and the difference is as large as 35 cm.

[0013]

[Table 2]

Incidentally, the molding die is provided with a gas vent clearance for releasing gas generated when a high-temperature resin material is injected.

Table 3 shows the degassing clearance without burr generation.

[0016]

[Table 3]

FIG. 4 shows a case in which a front surface gas vent groove is formed in the mold. A similar gas vent groove is provided in the holder engaging film portion 12 of the holder 11 shown in FIG. The numerical values shown in Table 3 are general values. Actually, the locking film portion 12 of the present invention can be formed by setting the clearance according to the fluidity of the resin material.

FIG. 5 is a partial cross-sectional view of a mating portion in a molding die of an LED fixture according to the present invention. In the figure, 21 is a mold cavity side, 22 is a mold core side, 23 is a hollow ejector pin, 24 is a pin,
5 is a hole as a gas vent groove, 26 is a gate as a resin injection port, and 27 is a thin film forming portion as a gas vent land provided between the hollow ejector pin 23 and the mold cavity 21.

When the resin material is injected into the mold by turning the gate 26 from the injection port 29, a molded part 28 is formed. When a resin material having good fluidity is injected, the resin material flows into the gas release land portion 27 to form the locking film portion 12, and the holder 11 is formed. The gas generated during the molding passes between the hollow ejector pins 23 and 24 and is discharged from the vent holes 25. When a resin material having poor fluidity is injected, the resin material does not flow into the gas release land portion 27, and gas generated during molding passes through the land portion 27 into the gap between the hollow ejector pin 23 and the pin 24. Street,
Discharged from the hole 25. As a result, the holder 13 without the locking film portion is formed. The gap between the hollow ejector pin 23 and the pin 24 is appropriately adjusted according to the resin material to be used and the shape and size of the molded component.

[0020]

As described above, according to the deformed part molding method of the present invention, a plurality of parts including a part having a thin film and a part without a thin film can be obtained by a single mold due to a difference in fluidity of a resin material. Thus, there is an effect that the mold is unified. Further, post-processing such as cutting off the locking rib is not required, and the workability is improved.

[Brief description of the drawings]

FIG. 1 is a plan view and a sectional view of a first component of the present invention.

FIG. 2 is a plan view and a sectional view of a second component of the present invention.

FIG. 3 is a flow characteristic diagram of a resin material.

FIG. 4 is a plan view and a partial cross-sectional view of a mold gas vent portion.

FIG. 5 is a partial sectional view showing the structure of the mold of the present invention.

FIG. 6 is a first example of a conventional example.

FIG. 7 is a second embodiment of the conventional example.

FIG. 8 is a third example of the conventional example.

FIG. 9 is a fourth embodiment of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Holder 12 Locking film part 13 Holder 25 Gas vent hole 27 Gas vent land part (thin film forming part)

Claims (1)

(57) [Claims] 1. A mold in which a gas venting portion is provided at an inner surface abutting portion of a cylindrical part, wherein one of a first resin having good fluidity and a second resin having lower fluidity than the first resin is provided. One part is injected, and the first resin is injected to form a first part having the locking film portion formed on the inner surface butted portion, and the second resin is injected to form the locking film portion. Forming a second part in which no is formed is formed.