Mandrel Tube Bending Machine

High-Precision Mandrel Tube Bending Machine

Achieve zero-wrinkle, tight-radius bends on thin-wall metal tubing.

Mandrel tube bending is a cold-forming process engineered to maintain internal structural integrity during tight-radius rotation. By inserting a solid or segmented mandrel inside the tube at the point of bend, a mandrel tube bending machine prevents wall collapsing, ovality, and internal wrinkling on challenging profiles.

How It Works

A mandrel tube bending system synchronizes five core mechanical components to control material flow during deformation:

Mandrel:

Positioned inside the tube at the tangent point to support the internal diameter.

Bend Die:

Forms the specified centerline radius as the drive head rotates.

Pressure Die:

Holds the outer tube wall against the bend die and advances to reduce wall thinning.

Wiper Die:

Positioned behind the bend die on the inside radius to prevent material bunching and surface wrinkling.

Clamp Die:

Secures the leading edge of the tube to the bend die during rotation.

All-Electric Mandrel Tube Bending Machine

Advantages of Mandrel Tube Bending Machine

Tight-Radius Bending: Executes bends down to 1.0D centerline radius without tube flattening.

Thin-Wall Support: Controls metal displacement on wall-thickness-to-diameter ratios below 1.5 percent.

Deformation Control: Eliminates internal wall collapsing and exterior flattening through continuous internal counter-pressure.

Surface Integrity: Maintains clean, smooth internal bores required for fluid flow applications.

Machine Models

Model Series	Tube OD Range	Max Wall Thickness	Max Bending Radius	Control Type	Accuracy
MTB-38 CNC	6 mm – 38 mm	2.5 mm	150 mm	Multi-Axis Servo CNC	±0.1°
MTB-63 NC	15 mm – 63 mm	4.0 mm	200 mm	Hydraulic NC	±0.15°
MTB-89 CNC	20 mm – 89 mm	5.5 mm	300 mm	Multi-Axis Servo CNC	±0.1°
MTB-114 CNC	25 mm – 114 mm	6.0 mm	400 mm	Heavy-Duty Servo CNC	±0.1°

Applications of Mandrel Tube Bending Machine

Automotive Exhaust Systems:

Forms tight-radius downpipes, manifolds, and converter tubes maintaining unrestricted gas flow.

Aerospace Fluid Lines:

Processes thin-wall titanium and aluminum tubing matching tight space constraints.

Hydraulic Circuits:

Preserves smooth inner wall surfaces to prevent fluid turbulence and pressure drops in high-pressure lines.

HVAC Systems:

Bends copper and aluminum tubing while maintaining uniform cross-sectional flow area.

Materials

Stainless Steel: Grades 304, 316, 316L, 409, 439

Carbon Steel: Seamless hydraulic tubing, structural grades ST37 and ST52

Aluminum Alloys: 6061-T6, 6063-T5, 3003

Copper Alloys: C11000 refrigeration grade tubing

Mandrel Types

Mandrel Type	Internal Structure	Best Suited Application
Plug Mandrel	Solid steel shank with contoured tip	Heavy-wall tubing with bend radius greater than 2.0D
Ball Mandrel	Central shank linked to 1 to 5 flexing steel balls	Thin-wall tubing with tight bend radius down to 1.0D
Segmented Mandrel	Interlocking ball segments with full inner contact	Oval, square, and custom non-circular profile shapes

Engineering Standards & Production Reliability

In-House Tooling Fabrication:

Machined hardened steel and bronze wiper dies customized to specific tube dimensions.

Multi-Axis Servo Synchronization:

Controls mandrel extraction timing down to 0.01 seconds for clean retract cycles.

Inspection Integration:

Direct compatibility with measuring arms for automatic bend angle calibration.

Heavy-Bed Construction:

Stress-relieved steel frames minimize structural deflection during high-torque bending cycles.

FAQ

Q: How is the correct mandrel position determined?

A: The mandrel tip is set slightly forward of the tangent point where the bend begins. Precise placement depends on tube wall thickness, outer diameter, and centerline radius.

Q: When is a wiper die required alongside a mandrel?

A: A wiper die is required when the bend radius is less than 2.0D or when wall thickness ratios drop below 2 percent to prevent wrinkling on the inside curve.

Q: How is wall thinning mitigated on tight bends?

A: A pressure die booster pushes the tube material into the bend zone during rotation, replacing stretched material and controlling wall reduction.

Q: What lubrication is required during operation?

A: High-viscosity liquids or synthetic pastes applied through internal mandrel lubrication ports ensure consistent tool life and clean extraction.

Q: Can these machines process non-round profiles?

A: Custom-profile dies and multi-segment mandrels allow processing of square, rectangular, and oval tubing.

Request a Custom Tube Bending Feasibility Assessment

Submit your tube CAD drawings along with material specifications for complete bend radius verification and cycle time calculations.

Request Technical Quote

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