Hairpin Bending: Leg Length and Kink Control
How a hairpin line is specified: conductor feed without kinking, bend radius against springback, leg length held to drawing, and what a run-off checks.
How a hairpin line is specified
The conductor decides most of the line: its diameter, material and temper, then the leg length, the bend radius and the width across the U. A long, thin conductor bends easily and kinks just as easily, so the feed and the bend have to be designed together rather than as separate stations.
Station sequence
The conductor is cut to length, fed into a jig that holds both legs, and bent into a U at the rotary cam stations. Leg length and bend radius are set by the tooling, so the shape does not depend on how the operator loads the wire. The formed hairpin is then transferred to the next operation or packed.
Our hairpin machines carry eight die-steel jigs through pushing and rotary cam stations, with two vibration discs feeding the parts. Control is a Delta PLC with a Wenview touch screen, and the moving parts sit behind a safety grating.
What decides reject rate
- Kinking at feed. A conductor pushed faster than it can straighten buckles, and a buckled hairpin cannot be straightened without marks.
- Springback. The bend radius after release differs from the radius on the tool. If the tool is not set for the material temper, every part drifts the same way.
- Leg length drift. Cam wear shows up first as one leg getting longer than the other, which only fails at the next assembly station.
- Feed roll marks. Roll pressure that is too high leaves marks that become crack starters on thin wire.
What we need from you
- Drawing with leg length, bend radius and the tolerance on both legs
- Conductor diameter, material and temper, and whether it arrives on a spool or pre-cut
- Target cycle time, annual volume and shifts per day
- What happens to the hairpin next — insertion, welding or packing — since that sets the handling
How the project runs
Quote from drawing, tooling design, build, then run-off with your conductor in our plant in Chashan, Dongguan. Machines are built to your samples and drawings, and the drawing set is agreed before metal is cut. Two years warranty, with operator training at run-off.
Send a drawing to [email protected] or call +86-18123647785. Related lines: hose clamp assembly machines, tube cutting machines.
Machines for this part: Hairpin Assembly Machine — the models we build, with station count and cycle time per line.
Send the drawing for this line. We come back with station layout, cycle time and price.
A quote normally takes three working days once the part information is complete. If something is missing we tell you which drawing is needed instead of guessing a price.
- 012D drawing or STEP file, and the sub-parts
- 02Material and surface finish of each component
- 03Target cycle time, annual volume, shifts per day
- 04The defect you cannot ship — leak, torque, appearance
- 05Bottle neck thread or mating part