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Pressure Tape

Pressure Tape refers to a pressure indicating sensor film that can measure pressure between any two surfaces that touch, mate, or impact. Pressure Tape is synonymous with the following other terms: Fuji Paper, Fuji Prescale®, Fuji Prescale® Film, Fuji Pressure Film, Fuji Pressure Paper, Nip Impression Paper, Prescale®, Prescale® Film, Prescale® Fuji Film, Pressure Indicating Film, Pressure Measurement Film, and Pressure Paper

Pressure Tape was used in a study by Thomas Schreier-Alt, Frank Rehme, Frank Ansorge, and Herbert Reichl titled, Simulation and Experimental Analysis of Large Area Substrate Overmolding with Epoxy Molding Compounds. This paper presents new experimental and numerical methods to characterize the transfer molding of substrates with epoxy polymer. Thomas Schreier-Alt, et al, investigated multi chip modules on ceramic panels as well as on printed circuit boards. Fuji Prescale® Pressure Tape was used to measure the pressure distribution within the mold cavities at temperatures up to 180 C.

Figure 1 illustrates the transfer molding encapsulation of an electronic component using Fuji Prescale® Pressure Tape to measure pressure within the mold. In Step A, pellet and substrate are inserted into the mold tool and preheated. Pressure Tape has been placed onto the substrate. In Step B, the plunger presses on the pellet, which melts. In Step C, the melted polymer is pressed into the cavity, and the material is pre-cured for 2 min. In Step D, the plunger is removed together with the cull, and the substrate is removed.

using prescale
Fig 1: Using Fuji Prescale® Pressure Tape to Measure Pressure during the Transfer Molding Encapsulation of Electronic Components

Homogeneous material flow and pressure distribution within the cavity is of particular importance for encapsulation of mechanically sensitive parts. With the use of Fuji Prescale® Pressure Tape, a fast and inexpensive estimation of the pressure distribution was achieved. The accuracy of this pressure measurement method was confirmed using conventional pressure sensors located at different positions within the mold walls. The Pressure Tape results are also in agreement with numerical simulations.

Figure 2 shows the results of an experiment using Fuji Prescale® Pressure Tape. Shown at left are the mold halves with Fuji Prescale in the mold cavity. A simulation versus experimental results using Pressure Tape is shown in the center. The pressure profile from the polymer flow is shown at right with an inset showing a short shot experimental result.

Figure 1 is a picture of a solid disc brake system. Figure 2 is a simplified schematic of the system.

experimental results
Fig 2: Experimental Results Using a Simulation and Fuji Prescale® Pressure Tape