How to calculate of load of Servo and Ball screw

Servo Press Technology and Torque Calculation

Servo press machines represent a new era in metal machining, combining high precision and formability with the productivity of conventional mechanical presses. Since their introduction, servo presses have gained widespread acceptance in the metal forming industry, establishing themselves as a unique category in the press field.

Advantages of Servo Presses

Servo presses have become popular for sheet metal forming due to their:

• Flexibility: Allows for various motion profiles, enabling complex operations.
• Controllability: Ensures precise control over speed, position, and force.
• Energy Efficiency: Minimizes power consumption during idle and partial load states.
• Tool Longevity: Reduces wear and tear on tools, cutting down manufacturing costs.

These benefits lead to significant savings in production costs, making servo presses an attractive choice for modern manufacturing operations.

Technology Behind Servo Presses

The servo press utilizes the latest technology to generate linear force using a ball screw mechanism. This approach eliminates the need for traditional mechanical linkages, offering smoother and more accurate force application.

To determine the appropriate servo motor torque, you must first choose the right ball screw based on the applied force. Reputable manufacturers such as Hiwin, THK, and Misumi provide catalogs detailing the specifications for various ball screw models.

Torque Calculation for Linear Motion

Torque (Ta) required for converting rotary motion to linear motion is calculated using the formula:

Ta = (F × L) ÷ (2π × Efficiency)

Where:

• Ta: Torque (N·m)
• F: Force (N)
• L: Lead or Pitch (m)
• Efficiency: Mechanical efficiency of the system

Example Calculation:

For a system with the following parameters:

• Force Capacity: 10 Ton = 100,000 N
• Ball Screw Pitch: 10 mm = 0.01 m
• Efficiency: 90% (0.9)

Ta = (100,000 × 0.01) ÷ (2 × 3.14 × 0.9)
Ta = 176.83 N·m

Therefore, a servo motor with a torque capacity of 176.8 N·m is required for a 10-ton force.

Torque Requirements for Different Forces

Using the same formula, the torque requirements for different force levels are calculated as follows:

Force (Ton)	Force (N)	Required Torque (N·m)
10	100,000	176.83
9	90,000	158.82
8	80,000	141.45
7	70,000	123.77
6	60,000	106.08
5	50,000	88.40

Conclusion

Servo presses represent a breakthrough in metal forming technology, offering unmatched precision and efficiency. Accurate torque calculations ensure optimal performance, minimizing operational costs and maximizing tool life. As servo technology evolves, it continues to revolutionize the manufacturing industry.