A Link-driven Mechanical Press is a specialized type of mechanical press that uses a unique link mechanism to control the motion of the slide, resulting in a motion profile that differs from that of traditional crank-driven presses. This provides significant advantages in certain applications by offering better performance, particularly in forming processes that require precision and reduced impact on the die.
Link-driven Mechanical Press Working Principle
In a traditional crank press, the slide’s motion follows a simple harmonic motion, with its speed symmetrically distributed along the stroke. This means the slide moves very fast near the bottom of the stroke and slower near the top. In contrast, the Link-driven Mechanical Press uses a complex link system (such as four-bar or six-bar linkages) to replace or supplement the traditional crank mechanism.
The core principle involves converting the motor’s rotational motion into the slide’s reciprocating linear motion via multiple linkages, carefully modifying the speed curve of the slide. During the working stroke (when the slide moves downward to compress the workpiece), especially as it approaches the bottom dead center, the speed of the slide significantly slows down. This ensures that the slide applies pressure to the material for a longer duration, promoting plastic deformation and reducing material tearing. In the non-working stroke (when the slide returns), the speed increases to ensure the overall production cycle remains efficient.
This “slow down, fast up” characteristic is the defining feature of the Link-driven Mechanical Press.
Link-driven Mechanical Press Working Process
- Preparation Stage: The motor starts and drives the flywheel to store kinetic energy. The clutch is not engaged, and the slide is at the top dead center.
- Working Stroke (Slow): The clutch engages, and the flywheel’s stored energy is transmitted through the linkage system. The slide starts to move downward. As it approaches the workpiece, the linkage system slows down the speed, providing sufficient time for the material to deform plastically.
- Forming Stage (Slowest): When the slide reaches the bottom dead center, maximum pressure is applied to the workpiece. The slide almost comes to a halt at this point, ensuring the material flows and deforms precisely.
- Return Stroke (Fast): After the forming is complete, the linkage mechanism quickly returns the slide to the top dead center, while the flywheel recharges through the motor.
- Cycle: Once the slide returns to the top dead center, the clutch disengages, and the brake activates. The press then waits for the next cycle or stops.
Link-driven Mechanical Press Applications
The Link-driven Mechanical Press, due to its unique “slow down, fast up” speed profile, is particularly suitable for the following applications:
- Deep Drawing/Deep Stamping: The slow-speed phase during the working stroke effectively reduces material tearing and thinning of the walls, improving the quality of the parts.
- Hot and Cold Forging: The slow forming characteristic minimizes the impact on the die, extending its service life. Moreover, it allows the material to flow more evenly during the forging process, improving the quality of the finished product.
- Precision Stamping: The slide’s slow speed at the bottom dead center reduces impact and vibration during stamping, lowering noise and improving the cross-sectional quality of the stamped parts.
- Processes Requiring Long Holding Time: Some forming processes require the slide to remain at the bottom dead center for an extended time. The linkage mechanism can efficiently meet this need and ensure high-quality results.
Similar Products and Their Differences
The Link-driven Mechanical Press belongs to the broader category of mechanical presses. Its most common counterparts are the Crank-driven Mechanical Press and the Knee-driven Mechanical Press. Below is a comparison of the main differences between them:
| Feature | Link-driven Mechanical Press | Crank-driven Mechanical Press | Knee-driven Mechanical Press |
|---|---|---|---|
| Working Principle | Complex link mechanism that alters the speed curve of the slide | Simple crank-link mechanism with harmonic motion | Knee mechanism that provides high pressure and holding time |
| Slide Speed | “Slow down, fast up,” speed significantly slows during the working stroke | Symmetrical speed distribution, faster during working stroke | Very long hold time at bottom dead center, almost zero speed |
| Main Advantages | Reduces impact, extends die life, improves material flow | Simple structure, low cost, high production efficiency | Provides high pressure, excellent holding time |
| Typical Applications | Deep drawing, hot forging, precision forming | Blanking, punching, shallow drawing | Cold extrusion, precision pressing, straightening, embossing |
Conclusion
The Link-driven Mechanical Press Equipment, with its unique slow-forming characteristics, is particularly suitable for manufacturing processes that require high precision, extended die life, and efficient material flow. It offers significant advantages in applications such as deep drawing, hot forging, and precision stamping, where part quality and process control are crucial. Compared to traditional crank-driven presses, the Link-driven press provides more precise control, longer die life, and higher forming quality, making it an ideal choice for high-precision manufacturing processes.