Tube End Forming Machine Process Flow

1. Preparation Work

Material Inspection: Verify that the material, diameter, wall thickness, and other parameters of the metal tube meet processing requirements.

Die Installation: Install the appropriate forming dies (e.g., for flaring, reducing, etc.) based on the forming requirements. Adjust the die position and clamping force accordingly.

Equipment Setup: Set forming machine parameters such as pressure, speed, and stroke. Perform a dry run to ensure proper operation.

2. Loading and Clamping

Automatic/Manual Loading: Load the metal tube into the working area of the forming machine either manually or using a feeding mechanism.

Positioning and Fixing: Use fixtures or hydraulic clamping devices to secure the tube, ensuring the tube end is aligned with the die center to prevent misalignment.

3. Tube End Forming Process

Forming Methods (select one or more based on requirements): Flaring, reducing, flanging, bending.

Flaring: A tapered die is used to expand the tube end outward, forming a flared or bell mouth shape. This is a common metal tube processing method used for connections, welding, or assembly.

Typical applications include:Flared joints in exhaust pipes or oil lines

Brazing connections in air conditioning copper tubing

Flanged tube ends for improved sealing

Main Types of Flaring Processes:

Mechanical flaring (cold): Formed by die extrusion, suitable for copper, aluminum, and steel tubes.

Hydraulic flaring: A hydraulic cylinder drives the flaring head, ideal for large-diameter or thick-walled tubes.

Hot flaring: The tube end is heated before flaring, suitable for hard-to-deform materials like stainless steel.

Reducing: The tube end diameter is reduced using an extrusion die. This method meets requirements for connection, sealing, or assembly.Common applications include automotive exhaust pipes, hydraulic tubing, and furniture frames.

Main Types of Reducing Processes:

Mechanical reducing (cold): Radial die extrusion, suitable for ductile materials like copper, aluminum, and low-carbon steel.

Hydraulic reducing: A hydraulic cylinder drives the reducing die, ideal for thick-walled or large-diameter tubes.

Spinning reduction: Tube ends are gradually reduced through rotary spinning, suitable for high-precision thin-walled tubes.

Hot reducing: Heated tube ends are reduced, suitable for high-hardness materials like stainless steel or titanium alloys.

Flanging: The tube end is curled outward or inward to form a flange. This is a critical process used for connection, reinforcement, or sealing. Commonly used in pressure vessels, piping systems, and automotive components.

Main Types of Flanging Processes:

External flanging: Tube ends are flanged outward for external connections (e.g., piping flanges).

Internal flanging: Tube ends are flanged inward to reinforce the edge, commonly used for thin-walled components.

Compound flanging: Both internal and external flanging performed simultaneously for specialized connections using custom dies.

Bending: Tube ends are bent to a specific angle using rotary or press bending dies. This is one of the most common tube forming methods. Used in exhaust systems, furniture frames, and structural components.

Main Types of Bending Processes:

Cold bending: Performed at room temperature; efficient and cost-effective, suitable for carbon steel and aluminum tubes.

Hot bending: Tube is heated to its recrystallization temperature (~700–1000°C) before bending; reduces deformation resistance, suitable for high-strength materials.

Roll bending: Gradual forming using multiple rollers, suitable for large-radius, continuous bends.

Press bending: Die pressure forms the bend directly; offers high precision for complex shapes.

Mandrel (rotary) bending: Tube is bent around a fixed die; suitable for small-radius, high-accuracy bends.

Push bending: A hydraulic ram pushes the tube through a bending die; ideal for thick-walled or large-diameter tubes.

Forming Process: Dies driven by hydraulic or servo systems apply pressure to gradually shape the tube end. Multiple steps may be required (e.g., preforming, finishing).

4. Post-Forming Operations

Die Retraction: After forming, the die retracts to release the tube.

Deburring: Remove any burrs or sharp edges from the tube end using manual or automatic methods.

Inspection: Check dimensional accuracy and surface quality using tools such as go/no-go gauges or visual inspection systems.

5. Unloading and Sorting

Automatic Unloading: Robotic arms or slide mechanisms remove finished tubes from the working area.

Sorting and Stacking: Separate conforming and non-conforming parts for further processing (e.g., welding, assembly).

6. Equipment Maintenance

Die Cleaning: Remove residual metal chips or lubricants from the dies.

Lubrication and Maintenance: Regularly apply lubricant to moving parts and check hydraulic system pressure.

Key Safety and Quality Considerations

Precision Control: Ensure die alignment and forming parameters are stable to prevent tube end deformation or cracking.

Lubrication and Cooling: Apply lubricant during forming to reduce friction and prevent metal adhesion.

Safety Protection: Keep hands clear of the die area during operation. Machines are usually equipped with light curtains or emergency stop systems.