Why does an acrylic sheet help trace metal to achieve a vector file for CNC cutting? The logic trace electronic tracing board works because the tracing pin produces a magnetic field which is picked up by the tracing board, delivering an XY coordinate to the software some metal parts interfere with this process, but raising them above the board allows the pin in board to deliver accurate data. So placing this 1/8 inch acrylic sheet under the board allows me to trace around the edges and save the