Abstract: A method for preventing gate washout in process of plastic injection molding includes a step 1 of preparing a film connected to a concavity surface in a first mold and patterns printed on a top surface of the film; a step 2 of inserting a block slidably received in a passage in a second mold and located beside a pouring gate between the first mold and the second mold; a step 3 of injecting plastic material in the concavity via the pouring gate; a step 4 of moving the block toward the first mold before the plastic material in the concavity is solidified; and a step 5 of removing the second mold from the first mold.

Abstract: Disclosed is a gas injection mold structure for use in the field of gas auxiliary injection molding, comprising a male mold and a gas injection device. The gas injection device includes a head and a cylindrical body extending from the head. The male mold is formed with a cylindrical cell. The cylindrical body has an outer periphery and the cylindrical cell has an inner wall being formed with matching outer and internal threads, respectively, such that the gas injection device is removably threaded into and affixed to the cylindrical cell by means of the cylindrical body. The cylindrical body is formed with a plurality of vertical grooves along an entire length of sides thereof.

Abstract: The present invention provides a process for underfill encapsulating a flip chip which is driven by pressure. First, a metal foil is placed on a flip chip that has been connected to a substrate. Then, a downward pressure is applied to the metal foil so as to form a space among the metal foil, the flip chip, and the substrate. Then, an encapsulant is filled into the space under pressure. The chip on which the metal foil has been placed and that has been encapsulated is moved away. Then, another metal foil is placed on another flip chip that has been connected to the substrate to undergo the above-mentioned encapsulation process. Encapsulation of the next chip can begin without waiting the encapsulant packaging the prior chip to cure. Thus, the efficiency of the encapsulating machine can be greatly enhanced, and the conventional problems of encapsulant adhering to the mold can also be solved.