There are many criteria for categorization of injection molding machines, but it can generally be separated into the following types:

1. In driving manner:
• Hydraulic, all electrical, hybrid type injection molding machine.
2. In opening and closing direction of mold clamping unit:
• horizontal, vertical. Most of the machines are horizontal type. Vertical type is suitable for small insertion products.
3. In material processed:
• Thermoplastic material, thermosetting material (thermosetting), powder injection (metal, ceramic, alloy). Presently, most of the units are for thermoplastic materials.
4. In Hydraulic loop:
• Single loop, multiple loop (dual or triple) injection machines. Most of the units presently are single loop injection molding machines.
5. In hydraulic circuit control:
• Open loop, Close loop injection machines. Injection molding machines are generally of open loop type, but the close loop type is growing for machine stability.
6. In mold clamping structure:
• Toggle type, hydraulic, hydra- mech (two-plate type). In these 3 types, each has its own advantages and shortcomings. Presently toggle type is prevailing.
7. In Injection Mechanism:
   • Single color, (one set injection), multi-color (multi-component injection). Most of the existing units are single color unit.