CNC Tube Bender Mandrel Types: BallJoint vs Plug Mandrel Application Comparison

Target Keywords：tube bender mandrel, balljoint mandrel, plug mandrel, CNC bending mandrel selection 

Mandrels are critical tooling for thinwall tube processing. Many production failures come from improper mandrel selection. Two mainstream types are plug mandrel (fixed mandrel) and multisegment balljoint mandrel.

Plug mandrel features high rigidity and simple structure. It suits thickwall tubes with large bending radius. Benefits include low cost and long service life. However, it cannot follow tube deformation; it may jam and scratch inner walls for thinwall parts with small Rradius. It is widely used for thickwall round tubes with moderate precision requirements.

Balljoint mandrel consists of hinged segments that flex together with tube deformation. It is designed for smallR thinwall workpieces to maintain roundness and avoid collapse. Drawbacks are higher cost and faster wear; ball segments need regular replacement.

Selection guide: Use plug mandrel when wallthickness / OD＞0.06. Choose balljoint mandrel for thinwall tubes (wallthickness / OD＜0.04) with tight bending radius. Mandrel outer diameter should be slightly smaller than tube inner diameter. Excessive clearance reduces support; insufficient clearance causes jamming and inner scratches.