JPH0736726Y2 - Transfer molding machine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] In the present invention, a mold is provided on each of a movable platen and a base platen, and tablets (thermosetting resin) are supplied to pots provided on the mold. The present invention relates to a transfer molding machine that presses a movable body to supply it into a cavity after melting.

[Conventional technology]

Generally, when a resin package for sealing IC chips and the like is molded using this type of transfer molding machine, the tablet melted in the pot is pushed out of the movable body by a hydraulic cylinder to It is supplied into the cavity through the resin passage.

[Problems to be solved by the device]

However, as described above, when a hydraulic cylinder is used to drive a movable body, hydraulic oil is required and a cooling device for the hydraulic oil is also required. There is a problem in that positioning and repeatability are likely to deteriorate due to changes in oil temperature.

The present invention has been made in view of the above circumstances, and its purpose is to eliminate the need for hydraulic oil and its auxiliary equipment,
It is an object of the present invention to provide a transfer molding machine which can be reduced in size and weight and can be improved in positioning and repeatability.

[Means for Solving the Problems]

In order to achieve the above object, the transfer molding machine of the present invention has a drive mechanism for driving a movable body, a feed screw shaft connected to the movable body, and a nut body screwed to the feed screw shaft. It is composed of a rotating part for rotating this nut body and a pressure sensor provided at the tip of the feed screw shaft, and controls the rotating part based on the resin pressure detected by the pressure sensor, that is, the molten resin It manages pressure.

[Action]

In the transfer molding machine of the present invention, the rotating body rotates the nut body, and the rotation of the nut body moves the feed screw shaft along its axis,
The movable body is moved to supply the molten resin into the cavity of the mold. In this case, the control of the rotating portion is performed based on the resin pressure detected by the pressure sensor. That is, the pressure control of the molten resin extruded by the movable body is performed based on the resin pressure detected by the pressure sensor.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In these drawings, reference numeral 1 is a base platen fixed on a base 2, and tie bars 3 are slidably inserted at four corners of the base platen 1. A movable platen 4 is attached to the upper end of the tie bar 3, and an upper die (not shown) is attached to the lower surface of the movable platen 4.
Is fixed.

A cylinder frame 5 is attached to the lower end of the tie bar 3, and a cylinder frame 5, a tie bar 3, and a movable platen 4 are provided between the cylinder frame 5 and the base platen 1 with respect to the base platen 1. A mold clamping cylinder 6 for moving up and down is provided. A pneumatic booster 7 is connected to the mold clamping cylinder 6. Further, although not shown, the lower mold is fixed to the upper surface of the base platen 1 facing the upper mold through a bolster, and a molded product is provided between the upper mold and the lower mold. A cavity for molding the is formed.

Furthermore, a nut body 9 is rotatably installed below the base platen 1 via a mounting member 8.
A ball screw shaft 10 is screwed onto the nut body 9.
An upper end of the ball screw shaft 10 penetrates the base platen 1 and is connected to a plunger (movable body) that moves up and down in a pot formed in a lower mold. Further, a bush 11 for preventing rotation of the ball screw shaft is attached to the lower end of the ball screw shaft 10, and a pressure sensor (load cell) 12 is arranged at the upper end (tip) of the ball screw shaft 10. further,
A servo motor 14 is connected to the outer periphery of the nut body 9 via a timing belt 13. Then, by operating the servomotor 14, the ball screw shaft 10 is raised so that the tablet (filling resin) in the pot is pushed out by the plunger into the resin passage in the mold and is supplied into the cavity through the gate. It has become.

When performing transfer molding such as coating a resin package on an IC chip using the transfer molding machine configured as described above, first, in the mold open state, a resin tablet and a lead frame (insert parts ) Is set, then by the mold clamping cylinder 6,
The cylinder frame 5, the tie bar 3, and the movable platen 4 are lowered to close the mold, and after touching the mold, a constant pressure is applied to maintain the mold closed state, the servo motor 14 is rotated, and the timing belt 13 is used. The ball screw shaft 10 is raised by rotating the nut body 9 and the plunger in the lower mold is operated to inject the tablet melted in the pot into the cavity through the gate.

In this case, since the pressure sensor 12 is provided at the upper end (tip) of the ball screw shaft 10, it is possible to directly detect the resin pressure. The operation of raising the ball screw shaft 10 is based on the resin pressure detected by this pressure sensor 12
This is performed by feedback control of 14 (closed control). By controlling the servomotor 14 in this manner, transfer molding is smoothly performed and a resin package of the IC chip is molded. In this case, since the resin is injected into the cavity without using hydraulic pressure, hydraulic oil and its associated equipment (oil coolant, etc.) are not required, and the device can be made smaller and lighter, and it has low noise and consumption. The electric power can be reduced, the positioning and the repeatability can be improved, and the pressure control can be improved by the closed control of the pressure sensor 12 and the servomotor 14, and the maintenance can be reduced.

[Effect of device]

As described above, in the transfer molding machine of the present invention, the drive mechanism for driving the movable body has the feed screw shaft connected to the movable body, the nut body screwed to the feed screw shaft, and the nut. Since the rotating unit for rotating the body and the pressure sensor provided at the tip of the feed screw shaft are used, the nut body is rotated by the rotating unit, and the feed screw shaft is rotated by the rotation of the nut body. By moving along the axis and moving the movable body to supply the molten resin into the cavity of the mold, the resin can be injected into the cavity without using hydraulic pressure. In this case, the control of the rotating portion is performed based on the resin pressure detected by the pressure sensor. That is, since the pressure control of the molten resin extruded by the movable body is performed based on the resin pressure detected by the pressure sensor, the pressure control of the molten resin can be directly performed and highly reliable pressure control can be performed. It is possible to realize a transfer molding machine that can be performed. Therefore, hydraulic oil and its auxiliary equipment are not required, and it is possible to reduce the size and weight, and to have good positioning and repeatability, low noise, low power consumption, and low maintenance.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
The figure is a front view, and FIG. 2 is a side view. 1 ... Base platen, 4 ... Movable platen, 9 ... Nut body, 10 ... Ball screw shaft (feed screw shaft), 12 ... Pressure sensor, 14 ... Servo motor (rotating part).

Claims (1)

[Scope of utility model registration request] 1. A mold is provided on each of the movable platen and the base platen, a resin is supplied to a pot provided in the mold, the resin is melted, and then the molten resin is extruded by a movable body to melt the molten resin. In the transfer molding machine for supplying the inside of the cavity, a drive mechanism for driving the movable body rotates a feed screw shaft connected to the movable body, a nut body screwed to the feed screw shaft, and the nut body. A transfer molding machine comprising: a rotating part for rotating the pressure sensor and a pressure sensor provided at the tip of the feed screw shaft.