A Bonnell spring machine is a piece of manufacturing equipment used to automatically produce the hourglass-shaped springs that form the core of Bonnell-style mattresses. These machines coil metal wire, often at high speeds and with precise computer control, and can also incorporate knotting, heat treatment, and assembling functions to create a complete bonnell spring unit for mattresses.
Function and Process

• Coiling:
  The machine uses a coiling mechanism to shape a length of wire into the distinctive hourglass form of a bonnell spring.
• Knotting:
  After coiling, the ends of the spring are knotted to secure the structure.
• Heat Treatment:
  The springs are often heat-treated to improve their strength and stability, ensuring they maintain their shape and function over time.
• Assembly:
  Some machines also integrate an assembly function, combining the individual springs into larger mattress units.

Types of Machines

• Automatic Machines:
  Modern, highly automated machines with computerized control systems (PLCs) that handle all steps from wire coiling to spring assembly.
• Semi-Automatic Machines:
  Machines that automate some processes, like wire cutting and coiling, but may still require manual intervention for other steps.
• Manual Machines:
  Older machines require significant manual effort from the operator for most functions.

Key Features

• Precision Control:
  Modern machines utilize servo motors and PLCs to ensure consistent spring size and shape.
• Flexibility:
  They can be adjusted to meet the specifications for different mattress sizes and designs.
• Speed and Efficiency:
  High-speed machines can produce many springs per minute, improving production capacity and reducing labor costs.