When evaluating a brush sanding machine, you must prioritize the brush configuration and grit variety. Look for machines that offer modular brush heads (sisal, abrasive strips, or nylon) to handle different materials like solid wood, MDF, or primer. Ensure the machine features variable frequency speed control for both the brush rotation and the conveyor belt to prevent burning the workpiece. A critical spec is the maximum working width (typically 600mm to 1300mm) and the minimum workpiece length to ensure compatibility with your production line. Additionally, verify the vacuum suction efficiency of the conveyor bed, which is essential for stabilizing small or thin workpieces during the sanding process.