When sourcing an exposure machine, you must prioritize the light source type (UV LED vs. Metal Halide), as LED offers longer lifespans (up to 20,000 hours) and higher energy efficiency. Ensure the vacuum degree is sufficient (typically -0.08MPa or higher) to guarantee tight contact between the film and the substrate, preventing light leakage. Additionally, check the effective exposure area to ensure it matches your maximum workpiece size, and verify the uniformity of light intensity, which should ideally have a deviation of less than 10% across the entire surface.