JP2012066492A - Injection molding method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform mold forming without damaging a substrate by clamping the substrate with an adequate mold clamping load.SOLUTION: This apparatus includes a mold 100, a mold clamping mechanism 110 and an injection mechanism 120, inserts the substrate 10 mounted with an electronic component 7 between divided faces of the mold, clamps the substrate 10 with a mold clamping load FO at which the mold is closed and clamped, and injects molding resin 2 into a cavity 17 formed between the divided faces of the mold 100, thereby performs resin molding of the electronic component 7 mounted on the substrate 10. The injection molding apparatus further includes: a mold clamping load measuring instrument 13; an injection load measuring instrument 5 for measuring an injection load F2 in a direction opposite from the mold clamping load F0 corresponding to injection pressure acting on the mold when the mold is closed and the injection resin is injected into the cavity; and a control means for controlling the mold clamping load F0 within the tolerable range based on the measured data by the mold clamping load measuring instrument 13 and the measured data by the injection load measuring instrument 5.

Description

  The present invention relates to an injection molding method and apparatus for resin molding an electronic component mounted on a substrate.

  When molding electronic parts mounted on thin substrates such as polyimide tape and film with thermosetting resin, generally, a board with electronic parts is inserted between the split surfaces of the mold, and the mold is The substrate is clamped by the clamping load when it is closed and clamped, and in the clamped state, the molding resin is injected into the cavity formed between the split surfaces of the molding die so as to include the electronic components on the substrate. By curing, the electronic component mounted on the substrate is sealed.

  At that time, a predetermined injection pressure (10 to 15 MPa) is applied to the molding resin to remove bubbles in the resin, but the injection load (injection pressure × projected area of the cavity) is clamped. If the load is exceeded, the mold opens and there is a risk of burrs due to resin leakage.

  Therefore, the mold is clamped by applying a large mold clamping load that exceeds the injection load so that the mold does not open, but when clamping a thin substrate such as polyimide tape or film, clamp it with a mold clamping load that is more than necessary. If this happens, the substrate may be damaged or the substrate may be cut off, resulting in quality problems, and it is difficult to adjust the clamping load.

  On the other hand, in Patent Document 1 and Patent Document 2, the injection pressure of the molding material is detected at the time of injection molding, and the molding die is clamped with a mold clamping load exceeding the injection load, thereby preventing leakage of the molding material from the mold dividing surface. Deterrence techniques are described. For example, in the technique described in Patent Document 1, the pressure of the injection molding material is detected by a pressure sensor provided in the injection nozzle. In the technique described in Patent Document 2, the hydraulic pressure of the injection cylinder that applies pressure to the injection molding material is detected by a pressure sensor, and the data is used as the injection pressure.

JP 2001-287252 A Japanese Patent Laying-Open No. 2005-231176

  However, when the pressure of the injection molding material is directly measured by the pressure sensor as in the technique described in Patent Document 1, due to a measurement error caused by expansion / contraction of the pressure sensor due to temperature variation of the molding material or a difference in viscosity of the resin. The measurement value may become unstable and accurate measurement may not be possible. In addition, as in the technique described in Patent Document 2, the method of measuring the hydraulic pressure of the injection cylinder is not only responsive, but also measures the pressure on the input side that applies the injection pressure. Unlike measuring the load applied to the mold, there is a possibility that accurate measurement cannot be performed.

  To prevent the mold clamping load from falling below the injection load and opening the mold, it is only necessary to simply increase the mold clamping load to exceed the injection load. When a thin substrate is clamped by a clamping load, the substrate must be clamped with an appropriate clamping load that is not too weak and not too strong, and the actual load acting on the mold according to the injection pressure Need to be accurately grasped.

  In view of the above circumstances, an object of the present invention is to provide an injection molding method and apparatus which can be molded without damaging the substrate by clamping the substrate with an appropriate clamping load.

  In order to solve the above-mentioned problem, the injection molding method of the present invention is characterized in that the substrate mounted with electronic components is inserted between the split surfaces of the mold, and the mold clamping load when the mold is closed and clamped is used. An electronic component mounted on the substrate is clamped by injecting a molding resin into a cavity formed between the split surfaces of the mold so as to include the electronic component on the substrate in a clamped state. An injection molding method for resin molding, in which the mold is clamped and the molding resin is injected into the cavity, and the injection is in the direction opposite to the mold clamping load according to the injection pressure acting on the mold The load is measured by a load measuring device, and the mold clamping load is controlled within an allowable range according to the measured injection load.

  The injection molding apparatus of the present invention includes a molding die, a clamping mechanism for clamping the molding die, and an injection mechanism for injecting molding resin into a cavity of the molding die. Inserting a substrate with electronic components between the dividing surfaces, clamping the substrate with a clamping force when the mold is closed and clamping, and including the electronic components on the substrate in the clamped state An injection molding apparatus for resin molding an electronic component mounted on the substrate by injecting a molding resin into a cavity formed between the divided surfaces of the mold, wherein the mold clamping measures the mold clamping load. A load measuring means and an injection for measuring an injection load opposite to the mold clamping load according to an injection pressure acting on the molding die when the molding die is clamped and a molding resin is injected into the cavity Load measuring means Characterized control means for controlling the allowable range the mold clamping load on the basis of the measurement data of the measurement data and the exit load measuring means of the clamping force measuring means, by comprising.

  According to the injection molding method and apparatus of the present invention, the injection load in the direction opposite to the clamping load acting on the molding die is directly measured, and the clamping load is controlled within an allowable range according to the injection load. The mold clamping load can be controlled with high accuracy based on the injection load actually applied to the mold without being affected by variations due to the characteristics of the resin. Therefore, the substrate can be clamped with a minimum clamping load, and damage due to the substrate clamping can be reduced to improve the quality.

It is a schematic block diagram of the injection molding apparatus of embodiment of this invention. It is process explanatory drawing at the time of carrying out resin molding using the injection molding apparatus, and is a figure which shows the state which set the board | substrate with which the electronic component was mounted between the division surfaces of a shaping | molding die. It is a figure which shows the state which is performing mold clamping as the next process of FIG. It is a figure which shows the state which is injecting the resin for shaping | molding as the next process of FIG. It is a characteristic view which shows the time change of a mold clamping load and an injection load.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the injection molding apparatus according to the embodiment is a vertical type, and includes a molding die 100, a clamping mechanism 110, an injection mechanism 120, and a control means (not shown).

  This injection molding apparatus inserts the substrate 10 on which the electronic component 7 is mounted between the split surfaces of the molding die 100, clamps the substrate 10 with the clamping force F0 when the molding die 100 is closed and clamped, and the clamp In this state, the molding resin 2 is injected into the cavity 17 formed between the divided surfaces of the molding die 100 so as to include the electronic component 7 on the substrate 10, so that the electronic component 7 mounted on the substrate 10 is resin-molded. To do.

  The mold 100 includes an upper mold 9 that is a fixed mold and a lower mold 11 that is a movable mold, and the upper mold 9 and the lower mold 11 face each other vertically. The dividing surfaces of the mold 100 are the lower surface of the upper mold 9 and the upper surface of the lower mold 11 that face each other in the vertical direction. A recess 11a is formed on the upper surface of the lower mold 11, and the substrate 10 on which the electronic component 7 is mounted is set in the recess 11a. Further, on the lower surface of the upper die 9, a frame-shaped clamp convex portion 9 a that presses against the upper surface of the substrate 10 set in the recess 11 a of the lower die 11 and clamps the substrate 10 is provided. When the substrate 10 on which the electronic component 7 is mounted is set on the upper surface of the lower mold 11 and the upper mold 9 and the lower mold 11 are closed, a cavity 17 for injecting resin is formed inside the clamp protrusion 9a. The electronic component 7 is included in 17.

  The mold clamping mechanism 110 has an upper end fixed plate 1, a lower movable plate 12, and a lower base plate 16, and the upper mold 9 is fixed to the lower surface of the fixed plate 1. The lower mold 11 is fixed to the upper surface of the movable plate 12. The fixed plate 1 and the base plate 16 are connected to each other by four guide posts 18, and the movable plate 12 moves in the vertical direction along the guide posts 18. On the lower side of the movable plate 12, a mold clamping drive source 15 that applies a mold clamping load to the molding die 100 by moving the movable plate 12 up and down, and a mold clamping load measuring instrument (a mold clamping load) that measures the mold clamping load F0. Measuring means) 13.

  The injection mechanism 120 is of a plunger type, and has an injection drive source 3 for pouring a molding resin (such as an epoxy resin) 2 heated and melted into the cavity 17 of the mold 100 with the plunger 6, and a plunger ( It has an injection load measuring device (injection load measuring means) 5 for measuring an injection load F2 applied to the plunger 6 when the molding resin is press-fitted into the mold 100 by the mechanical component) 6. The injection load F2 measured by the injection load measuring instrument 5 acts on the mold 100 as a load F1 opposite to the mold clamping load F0. The control means has a function of controlling the mold clamping load F0 within an allowable range based on the measurement data of the mold clamping load measuring device 13 and the measurement data of the injection load measuring device 5.

Next, an example of the injection molding method will be described.
When the electronic component 7 mounted on the substrate 10 is resin-molded, first, as shown in FIG. 2, the movable plate 12 is lowered by the mold clamping mechanism 14 in the recess 11 a of the lower mold 11. A thin substrate 10 made of polyimide tape or film is supplied. An electronic component (device) 7 such as a bare chip or WLCSP is mounted on the substrate 10 in advance.

  When the supply of the substrate 10 is completed, the movable plate 12 is raised by the mold clamping mechanism 14 to close the mold 100, and the substrate 10 is clamped by the lower mold 11 and the upper mold 9 by the mold clamping load F0 when the mold is clamped. . The mold clamping load F0 at this time is measured and controlled by the mold clamping load measuring device 13. Although the mold clamping load varies depending on the material of the substrate 10 to be clamped, it is set lower as the softer one such as a film or tape, and set higher as the harder one. For example, in the case of metal, the pressure is set to about 100 to 350 MPa.

  When the mold clamping is completed, the molding resin 2 is injected into the cavity 17 between the upper mold 9 and the lower mold 11 heated to, for example, a temperature of 175 to 180 ° C. by a heating unit (not shown). When the cavity 17 is full, an increase in load is measured by the injection load measuring device 5, and therefore pressurization is performed until a predetermined load (about 10 to 15 MPa in terms of pressure) is reached. Assuming that the mold clamping load at this time is F0 and the injection load is F2, a mold clamping load F0 for closing the mold 100 and an injection load F2 for opening the mold 100 act on the movable plate 12. . At this stage, if the minimum mold clamping load F0 necessary for closing the mold 100 is not achieved, the mold 100 will open against the injection load F2, which may cause resin leakage and burrs. Become.

  Therefore, as shown in FIG. 5, the control means adds the injection load F2 measured by the injection load measuring instrument 5 to the initial mold clamping load F0, and updates F0 + F2 as a new F0, thereby setting the mold 100. Clamping load control is performed to prevent opening of the mold. Then, the mold clamping with the updated new mold clamping load F0 is continued until the resin is cured, and after the curing time of about 80 seconds to 120 seconds has elapsed, the injection load F2 is removed and the mold clamping load F0 is removed. I do. When this operation is completed, the lower mold 11 is lowered, the molded substrate 10 is taken out, and the molding is completed.

  As described above, the injection load F2 opposite to the mold clamping load F0 acting on the mold 100 is directly measured, and the mold clamping load F0 is controlled within an allowable range according to the injection load F2. The mold clamping load F0 can be controlled with high accuracy based on the injection load F2 actually applied to the mold 100 without being affected by variations due to the characteristics of the resin 2. Therefore, the substrate 10 can be clamped with the minimum necessary clamping load F0, and damage due to the clamping of the substrate 10 can be reduced to improve the quality.

  In particular, in the injection molding apparatus of the present embodiment, the load measuring device 5 that directly measures the load acting on the mechanical component (plunger 6) of the injection mechanism 120 is provided as the injection load measuring means. The injection load F2 can be measured, and the mold clamping load F0 with high accuracy for clamping the substrate 10 can be controlled.

  In the above embodiment, the electronic component 7 mounted on the upper surface side of the substrate 10 is molded. However, the electronic component mounted on the lower surface side can also be molded. Further, the present invention can be applied to the case where the electronic components on both sides of the substrate 10 are molded, and the shape of the mold is not limited.

  In the above embodiment, the injection direction of the molding resin is set downward, but the injection direction may be any direction with respect to the mold clamping direction.

2 Molding resin 5 Injection load measuring device (injection load measuring means)
6 Plunger (mechanical parts)
7 Electronic component 10 Substrate 13 Clamping load measuring device (Clamping load measuring means)
17 Cavity 100 Mold 110 Mold clamping mechanism 120 Injection mechanism

Claims (3)

A substrate on which electronic components are mounted is inserted between the dividing surfaces of the mold, the substrate is clamped by a clamping load when the mold is closed and clamped, and the electronic components on the substrate are clamped. An injection molding method of resin molding an electronic component mounted on the substrate by injecting molding resin into cavities formed between the split surfaces of the mold so as to include,
When the mold is clamped and a molding resin is injected into the cavity, an injection load opposite to the mold clamping load corresponding to the injection pressure acting on the mold is measured by a load measuring instrument, An injection molding method characterized by controlling the mold clamping load within an allowable range in accordance with the measured injection load. A molding die, a clamping mechanism for clamping the molding die, and an injection mechanism for injecting molding resin into a cavity of the molding die, and an electronic component is mounted between the divided surfaces of the molding die Clamping the substrate by a clamping load when the substrate is inserted and the mold is closed and clamped, and is formed between the divided surfaces of the mold so as to include the electronic components on the substrate in the clamped state. An injection molding apparatus for resin molding an electronic component mounted on the substrate by injecting a molding resin into the cavity,
Mold clamping load measuring means for measuring the mold clamping load;
An injection load measuring means for measuring an injection load opposite to the mold clamping load according to an injection pressure acting on the mold when the mold is clamped and a molding resin is injected into the cavity;
Control means for controlling the mold clamping load to an allowable range based on the measurement data of the mold clamping load measuring means and the measurement data of the injection load measuring means;
An injection molding apparatus comprising:   The injection molding apparatus according to claim 2, wherein a load measuring device that directly measures a load acting on a mechanical component of the injection mechanism is provided as the injection load measuring means.

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