ATEC

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ATEC

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ATEC

The Automated Thermal Expansion Coefficient System is designed to measure the dimensional stability (IPC.2.4.39) and in-plane thermal expansion coefficients of printed circuit boards, thin laminates, and foils.

The ATEC is a "machine vision" based system providing precise thermal expansion coefficient measurements on thin plastic films, laminates, and foils from ambient temperatures to 250 degrees C. The ATEC is capable of continuous thermal expansion measurements above and below the sample glass transition temperature. The system simultaneously measures expansion and strain in orthogonal directions, e.g. warp and fill, to determine sample anisotropy. The system is non-contacting, thus, no external stresses are introduced during measurement.

The graph below shows i n-plane thermal expansion plots which are typical ATEC data obtained on an 11" by 11" unclad laminate. A total of four simultaneous measurements are made: two in the fill direction and two in the warp direction. These data illustrate the anisotropic expansion characteristics of this laminate. The average fill coefficient of thermal expansion (slope of expansion curve) is 17.90 PPM/ ° C. In contrast, the average warp or machine direction CTE is only 12.07 PPM/ ° C.

The graph of Expansion Display (below) shows the "magnified" laminate expansion over the temperature 50 ° C to 150 ° C in “center of mass” coordinates. The expansion is anisotropic with the Y expansion (fill direction) much larger than the X expansion (warp or machine direction). Isotropic laminates would produce a "square" center of mass display.