When evaluating machinery, prioritize the clamping force (measured in tons) and injection volume (measured in grams/cm³) to ensure they match your production requirements. For high-quality sandals, look for machines with multi-color injection capabilities (e.g., 2-color or 3-color rotary machines) and PLC control systems (like Siemens or Omron) for precise temperature and pressure management. Additionally, verify the mold station count; a 20 or 24-station rotary machine is standard for balancing output speed with cooling time.