The structure of a Quick Mold Change System (SMED) can be analyzed from two dimensions: functional modules and technical types.
⚙️ By Functional Modules
A complete quick mold change system typically consists of the following four core subsystems:
1. Clamping and Positioning Mechanism
This is the core of the system, responsible for reliably fixing and accurately positioning the mold. Based on the clamping principle, it is mainly divided into three categories:
• Mechanical Swing Type: The mold is tightened through a mechanical structure; a uniform clamping mechanism is required on the back of the mold.
• Hydraulic Plate Type: A hydraulic cylinder drives a pressure plate to clamp the mold from all sides; this is currently the most widely used form.
• Magnetic Chuck Type: The mold is attracted from the back by an electro-permanent magnet template; the clamping force is uniform, and there is no interference around the mold.
2. Power and Hydraulic/Pneumatic Unit
This provides power to the clamping mechanism. The hydraulic system consists of a pump station, valve group, pipelines, and hydraulic cylinders, etc., and clamping and releasing are achieved by controlling the oil pressure and flow rate. Some systems also utilize pneumatic components, characterized by rapid action and simple structure.
3. Mold Support and Guiding Structure
Ensuring the accuracy and safety of mold installation and operation, mainly including:
• Positioning rings/pins: Guaranteeing the repeatability of mold positioning on the machine.
• Support blocks/pads: Used to support the weight of the mold, facilitating hoisting and adjustment.
• Guide rails and sliders: Used to support and move the mold in mobile worktable mold changing systems.
4. Control and Sensing System
As the "nerve center" of the system, it is responsible for logic control and safety monitoring.
• Control section: Based on a PLC or dedicated controller, it receives operating commands, controls the power unit's actions, and communicates with the host machine.
• Sensing section: Includes various sensors such as pressure, displacement, proximity, and magnetic flux, used for real-time monitoring of clamping force, mold position, and safety status, achieving automatic protection and alarm.
🔩 Classification by Technology Type
From an engineering application perspective, common quick mold change systems typically combine the following structures:
• Quick Mold Change System for Injection Molding Machines
This system has a relatively centralized structure, mainly consisting of clamping units (hydraulic or magnetic) on the stationary/moving mold plates, quick connectors (for water, oil, gas, and electricity), and a control system. During changeover, the mold moves in and out with the worktable or crane, and clamping, positioning, and pipeline connection are completed with a single button operation.
• Hydraulic Clamping System for Punch Presses/Presses
This system revolves around the press worktable and consists of a hydraulic clamping body, hydraulic cylinders, a hydraulic pump station, and a PLC control system. Its core function is to automatically clamp and release the mold directly on the press slide.
• Fully Automated Mold Change Production Line Structure
This is the most complex system, commonly found in high-end production lines such as thermoforming. It uses a mold changing trolley and a mobile workbench as its carrier, integrating multiple devices such as quick mold changing, quick end effector changing, automatic mold feeding, and automatic connection of water, oil, gas, and electricity. It also achieves fully automatic "one-click mold changing" through a central control system.
