When sourcing aluminum frames, the alloy grade is paramount; 6063-T5 aluminum is the industry standard for its excellent balance of strength and surface finish quality. Pay close attention to the wall thickness, which should ideally be between 1.2mm and 2.0mm to ensure structural integrity for large glass inserts. Additionally, verify the surface treatment process, such as anodizing (minimum 10 microns), powder coating, or electrophoresis, to ensure resistance to corrosion and scratches in high-moisture environments like kitchens.