1. Overview of Automatic Crank Shear Machine

The Automatic Crank Shear Machine is an advanced mechanical cutting device designed to perform precise and high-speed shearing operations automatically, without the need for manual intervention.
It is based on the traditional crank and connecting rod mechanism, but integrated with modern automation, servo control, and electronic synchronization technologies, enabling continuous, accurate, and intelligent cutting of metal billets, plates, and rolled materials.

This machine is widely used in steel rolling production lines, metal plate processing plants, and continuous casting workshops, where high efficiency and precise length cutting are essential.
By integrating an automatic measuring system, programmable control (PLC), and real-time feedback sensors, the automatic crank shear can automatically adjust cutting speed and timing according to the material’s rolling speed, thus achieving fully synchronized operation with the production line.

2. Working Principle

The automatic crank shear machine operates on the crank-slider mechanism, converting the rotational motion of the motor into a reciprocating linear motion of the blade frame.
However, unlike conventional crank shears, the automatic type includes a servo-driven synchronization system and electronic length measuring system.

The working process can be summarized as follows:

1. Power Transmission:
   The motor drives the flywheel, and through a clutch, the torque is transmitted to the crankshaft.

2. Crank and Connecting Rod Movement:
   The crankshaft converts rotary motion into reciprocating linear motion of the blade carrier.

3. Automatic Measurement:
   A length sensor (encoder or laser) continuously measures the material speed and length.

4. Intelligent Control:
   The PLC calculates the optimal cutting point and sends commands to engage the clutch or servo actuator at the precise moment.

5. Cutting Action:
   The upper blade descends and shears the material, then returns automatically.

6. Feedback Correction:
   The system compares the actual cutting length with the target value and automatically compensates for the next cycle.

This process allows real-time adaptive cutting, ensuring accuracy even when the rolling speed fluctuates.

3. Main Structural Components

A typical Automatic Crank Shear Machine is composed of the following key parts:

1. Main Frame:
   Heavy-duty welded steel structure supporting all moving and transmission components.

2. Crankshaft and Connecting Rod Assembly:
   Transmits rotary motion into reciprocating blade movement.

3. Upper and Lower Blades:
   High-speed steel or tungsten alloy, mounted at precise shear angles.

4. Flywheel and Clutch Unit:
   Flywheel stores kinetic energy; clutch engages or disengages according to PLC commands.

5. Servo Drive & Encoder System:
   Synchronizes crank rotation speed with line speed, ensuring accurate cut timing.

6. PLC Control Cabinet:
   Core control unit with human-machine interface (HMI) for parameter setting.

7. Automatic Measuring System:
   Includes encoder or laser sensor for length and speed detection.

8. Hydraulic or Pneumatic Actuators:
   Control blade clearance adjustment and clutch actuation.

9. Lubrication & Cooling System:
   Provides automatic oil circulation to bearings and crank pins.

10. Safety Protection System:
    Encloses moving parts with guards and provides emergency stop circuits.

4. Features and Advantages

1. Fully Automatic Control:
   No manual intervention needed; automatic start, cut, and stop.

2. High Cutting Precision:
   ±1 mm length accuracy due to servo synchronization and feedback correction.

3. High Speed:
   Suitable for continuous cutting at line speeds up to 120 m/min.

4. Energy Efficiency:
   Flywheel energy recovery and intelligent clutch engagement reduce power loss.

5. Real-time Monitoring:
   HMI display for status, length, and production count.

6. Stable Operation:
   Mechanical crank system ensures consistent motion curve and low vibration.

7. Maintenance-friendly:
   Modular design, automatic lubrication, and fault diagnosis.

8. Data Connectivity:
   Can be integrated with MES or SCADA systems for smart manufacturing.

5. Control System Description

The control system is the core of the automatic crank shear.
It typically consists of:

• Programmable Logic Controller (PLC) for logic sequencing and timing.

• Servo Drive and Motor Controller to regulate crankshaft speed.

• Encoder/Laser Sensor for continuous measurement of material movement.

• Human–Machine Interface (HMI) for operator interaction and status display.

• Communication Interface (Ethernet/Profinet) for networked control.

The PLC continuously receives length data, compares it to the preset cutting length, and commands the clutch or servo to execute cutting precisely at the desired position.
This ensures synchronized shearing, even during acceleration or deceleration of the rolling line.

6. Applications

• Hot and Cold Rolling Mills:
  For automatic cutting of billets, plates, and strips.

• Continuous Casting Lines:
  Shearing of hot billets before cooling bed.

• Metal Plate Processing Plants:
  Length trimming for automotive or construction steel plates.

• Pipe and Tube Mills:
  For cutting steel tubes before forming.

• Integrated Steel Plants:
  As part of automatic product sizing and bundling lines.

7. Maintenance and Safety

1. Periodically check crankshaft bearings and lubrication system.

2. Calibrate encoder and sensors regularly.

3. Replace worn blades according to working hours.

4. Keep clutch and flywheel clean and well-balanced.

5. Test emergency stop and interlock systems monthly.

6. Avoid overload cutting to protect crank mechanism.

Conclusion

The Automatic Crank Shear Machine represents a major evolution in the field of mechanical shearing technology.
By combining the robustness of traditional crank systems with modern automation, servo synchronization, and intelligent feedback control, it offers an ideal solution for high-speed, high-precision, and fully automated cutting operations in modern metal processing industries.

It not only improves product quality and operational efficiency, but also aligns with the global trend of smart manufacturing and energy-efficient production.