JPH06204274A - Molding device for molded part for hoop-shaped lead frame - Google Patents

Abstract

PURPOSE:To lessen the displacement of the shift between the leads of a hoop- shaped lead frame and cavities for molded part molding when molded parts for packaging the lead parts of the hoop-shaped-lead frame are molded. CONSTITUTION:A means 5 for fixing a lead frame on the metal mold on at least one side of metal molds 1 and 2 is provided on the side of the entrance of the lead frame in the metal molds 1 and 2, while tension means 6 for pull- operating in a direction to separate the lead frame from the metal molds are provided on the side of the exit of the lead frame in the metal molds. Moreover, sensors 9 for detecting the front dimension of the lead frame between the front side surfaces of the lead frame in the lead frame transfer direction and lead terminals of the lead frame in molded parts D subsequent to a molding and the back dimension of the lead frame between the rear side surfaces of the lead frame in the lead frame transfer direction and the lead terminals are provided and the means 6 are actuated so as to move the sensors 9 and the means 6 to a site where the front dimension and the back dimension become roughly equal to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hoop-shaped lead frame used for manufacturing an electronic component such as a diode or a transistor, and a tip of a lead terminal provided at an appropriate pitch along the longitudinal direction of the lead frame. The present invention relates to an apparatus for molding a synthetic resin mold portion for packaging the element portion in the element portion in FIG.

[0002]

2. Description of the Related Art In general, a molding device for molding a lead frame of this type is well known in the prior art and, as shown in FIG. 1, a pair of left and right lead terminals A formed at an appropriate pitch P _{1. In a} hoop-shaped lead frame A in which an element portion such as a semiconductor chip is provided between ₁ , a suitable length L ₁ (L ₁ = L ₁ = L ₁ = L ₁ = L ₁
(P ₁ × (N-1)) part is sandwiched by a pair of upper and lower molds B and C, and is formed in a cavity E for molding a mold part, which is formed by recessing the mating surfaces of the molds B and C. By injecting the synthetic resin in a molten state, the mold portion D is inserted into each of the lead terminals A1 in the appropriate portion L1.
And then release the sandwiching of the lead frame A by the two dies B and C, and then the lead frame A
Is repeatedly transferred in the longitudinal direction by a length obtained by adding P ₁ to L ₁ .

[0003]

By the way, the pitch interval P ₁ in each lead terminal A ₁ of the hoop-shaped lead frame A and the pitch interval P ₂ in each cavity E of both molds B and C are as follows. Although the temperature is set to be equal when the temperature rises to a predetermined molding temperature, the pitch interval P ₁ at each lead terminal A ₁ of the lead frame A is set to be equal to each cavity E of both molds B and C.
Since there is a dimensional error of ± δ with respect to the pitch interval P ₂ in the standard value, the length L ₁ including the N lead terminals A ₁ in the lead frame A is
In both the molds B and C, there is a cumulative dimensional error of ± Δ = ± δ × (N−1) with respect to the length L ₂ including N cavities E.

Therefore, in the lead frame A,
N lead terminals A₁Including length L ₁, Both molds
Length L including N cavities E in B and C₂=
P₂X (N-1)) is the cumulative dimensional error ± Δ
Dimensional error ± δ per pitch interval is expanded by (N-1) times
Each lead in lead frame A
Terminal A₁In the cavity E in both molds B and C
On the other hand, is there a displacement in the longitudinal direction of the lead frame A?
, Lead terminal A in lead frame A₁But molding
As shown in FIG. 2, for each mold part D later
The lead frame transfer direction in the mold part D
Front side D₁Shifts so that it approaches
As shown in FIG.
Rear side D in the lame transfer direction₂Displacement displacement to approach
Front side D of the mold part D₁Karari
Terminal A₁Front dimension up to S₁And behind the mold part D
Side D₂To lead terminal A₁Rear dimension up to S₂And not perfect
In addition, this deviation displacement is
Length L₁, That is, the molding part that is molded once
It will increase in proportion to the number N of D.

Therefore, conventionally, the length L ₁ is appropriately shortened, in other words, the displacement N is reduced by reducing the number N of mold portions D molded at one time. Therefore, the conventional method has a problem that the cost required for molding the mold portion D is significantly increased because the number of mold portions D that can be molded by one molding operation is small.

An object of the present invention is to provide a molding apparatus for a molding section which can solve this problem.

[0007]

To achieve this technical object, the present invention provides a plurality of hoop-shaped lead frames provided with lead terminals at appropriate pitches on a mating surface along a path for transferring the hoop-shaped lead frames in the longitudinal direction thereof. In a molding unit for molding a mold, which comprises a pair of molds having a cavity for molding the mold, the lead frame is fixed to at least one of the molds on the inlet side of the lead frames of the molds. On the outlet side of the lead frame in both the molds, a pulling means for pulling and actuating the lead frame in a direction away from the molds is provided, and further, from the pulling means along the lead frame transfer direction. In the front part, the front dimension from the front side of the lead frame transfer direction in the molded part after molding to the lead terminal and the lead A sensor that detects the rear dimension from the rear side surface in the lame transfer direction to the lead terminal is provided. The pulling means has an associated structure for actuation.

[0008]

[Operation] With this configuration, even if there is an error between the pitch interval in each lead terminal of the lead frame and the pitch interval in each cavity of both molds, after molding the mold part Based on the result, it is possible to perform feedback control so that each lead terminal in the lead frame is properly aligned with each cavity in both molds. It is possible to reliably reduce the displacement displacement caused by an error in the pitch distance between the cavity and the cavity, and the displacement displacement increases in proportion to the number of mold parts that can be molded in one molding operation. This can be reliably prevented.

By the way, the displacement caused by an error between the pitch interval between the lead terminals of the lead frame and the pitch interval between the cavities of the two dies is caused by the last cavity of the cavities of the two dies. It is the maximum accumulated in the tee. Therefore, when the front and rear dimensions of the molded part after molding are detected by the sensor, this sensor is used as the last mold part among the mold parts formed by the two molds as described in "Claim 2". Since the difference between the front dimension and the rear dimension can be detected as the maximum value with high accuracy by arranging at the portion of, the feedback control can be performed more accurately.

[0010]

Therefore, according to the present invention, the number of mold parts that can be molded at one time can be increased under the condition that the displacement of the lead terminal with respect to the cavity is reduced. Thus, it is possible to form a mold portion having a high dimensional accuracy with a small difference between the front dimension and the rear dimension at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings of FIGS. In this figure, reference numeral 1 indicates a lower mold, and reference numeral 2 indicates an upper mold that moves up and down toward the lower mold 1. Between the two molds 1 and 2, the hoop-shaped lead is formed. The frame A is arranged so as to be transported along its longitudinal direction.

A portion of the lead frame A having a length L ₁ including N lead terminals A ₁ formed at an appropriate pitch P ₁ is sandwiched between the molds 1 and 2,
In this state, by injecting synthetic resin in a molten state into the cavities 3 and 4 formed in the recesses on the mating surfaces of the molds 1 and 2, the N at the portion of the length L _{1 in} the lead frame is injected. A mold part D is formed for each of the lead terminals A ₁ , and then the molds 1 and 2 are formed.
After the pinching of the lead frame A by the above is released, the lead frame A is transferred along the longitudinal direction by the length obtained by adding the P ₁ to the L ₁ to repeat each of the lead frames A. Lead terminal A ₁
That is, the molding of the mold portion D is continuously performed.

A pin 5 projecting from the lower mold 1 is provided on the inlet side of the lead frame A in both molds 1 and 2, and the pin 5 is sandwiched between the molds 1 and 2. The lead frame A is fixed to the lower die 1 by fitting and engaging with the feed hole A ₂ in the lead frame A immediately before attachment. In this case, the cavities 3 of the molds 1 and 2 are
Pitch P ₂ in 4, the lead frame standard value of the pitch spacing P ₁ at the lead terminals A ₁ of A error dimensions ± in the pitch P ₁ in (no error value)
The size is set to a size obtained by adding + δ to δ, or a size close to this.

On the other hand, on the outlet side of the lead frame A in both the molds 1 and 2, immediately before the lead frame A is sandwiched by the molds 1 and 2, the lead frame A is
A pulling means 6 is provided which is clamped by a pair of upper and lower clamp pieces 7 and 8 and is operated to pull appropriately by a stroke W in a direction away from the molds 1 and 2. Further, in the lead frame A, the last mold portion D among the mold portions D molded in the lead terminals A ₁ in the portions of the molds 1 and 2 having the appropriate length L ₁ is By arranging the sensor 9, with this sensor 9,
Figure 5 As shown in the said end of the lead from the rear side D ₂ of the front dimension S ₁ and the lead frame transfer direction from the front side D ₁ of the lead frame transport direction to the lead terminals A ₁ in the mold portion D terminal A ₁ It is configured to detect the back dimension S ₂ up to.

By connecting the sensor 9 and the pulling means 6 via the control circuit 10,
When the front dimension S ₁ of the rearmost mold portion D is smaller than the rear dimension S ₂ , the stroke W of the pulling means 6 is reduced by S ₂ −S _1, while the front dimension of the rearmost mold portion D is reduced. When S ₁ is larger than the rear dimension S ₂ , the stroke W of the pulling means 6 is S ₁ -S
It is configured to be larger by ₂ .

With this configuration, the pitch interval P at each lead terminal A ₁ of the lead frame A is
Even if there is an error between ₁ and the pitch interval P ₂ in the cavities 3 and 4 of both molds ₁ and ₂ , the mold portion D
Since the lead terminals A ₁ of the lead frame A can be feedback-controlled so as to be properly aligned with the cavities 3 and 4 of the molds 1 and 2 based on the result after molding. is there.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a mold portion is molded with respect to a lead frame.

FIG. 2 is a partially enlarged view of a lead frame after forming a mold part.

FIG. 3 is a partially enlarged view of the lead frame after forming a mold part.

FIG. 4 is a vertical sectional front view showing an embodiment of the present invention.

5 is an enlarged plan view taken along line VV of FIG.

[Explanation of symbols]

A lead frame A ₁ lead terminal D mold part D ₁ front side surface of mold part D ₂ rear side surface of mold part S ₁ front dimension of mold part S ₂ rear dimension of mold part 1, mold 3, 4 cavity 5 Fixing pin 6 Pulling means 9 Sensor 10 Control circuit

Claims (2)

[Claims] 1. A pair of molds in which a plurality of mold part forming cavities are recessed on a mating surface in a path for transferring a hoop-shaped lead frame provided with lead terminals at appropriate pitch intervals in a longitudinal direction thereof. In the molding device for arranging the mold portion, means for fixing the lead frame to at least one of the molds is provided on the inlet side of the lead frames of the both molds, and Provided on the outlet side is a pulling means for pulling the lead frame in a direction away from both molds,
Further, from the pulling means to the front part along the lead frame transfer direction, from the front side in the lead frame transfer direction in the molded part after molding to the lead terminal and from the rear side in the lead frame transfer direction to the lead terminal. A sensor adapted to detect the rear dimension is provided, and the sensor and the pulling means are related to operate the pulling means to a portion of the mold portion where the front dimension and the rear dimension are substantially equal to each other. A molding device for a hoop-shaped lead frame, which is characterized in that 2. The "claim 1" according to claim 1, characterized in that the sensor is arranged at a rearmost mold part of the mold parts molded in the cavities of the molds. Molding device for the hoop-shaped lead frame.