What Is Wire Tension in Wire Cut EDM?
Publication Date:2025-07-26 15:59:11
Author:KingredWire tension is the pulling force applied to the molybdenum wire as it travels between the upper and lower guide wheels during cutting.
This force is what keeps the wire straight, stable, and positioned precisely in the spark gap.
Without proper tension, no matter how advanced your CNC controller or power supply is, the cut will go wrong.
What Happens When Tension Is Too Low?
If the tension is too low, several problems will appear:
The wire starts to vibrate or wobble, especially at high feed speeds.
This causes zigzag cuts, poor straightness, and taper issues.
The wire might sag in the middle, shifting the spark gap position.
Corners become rounded or over-burned, especially in tight contours.
The overall surface becomes rougher due to unstable discharge condition.
What Happens When Tension Is Too High?
On the other hand, too much tension brings a different set of risks:
The wire becomes overstretched, which increases risk of breakage.
High tension amplifies vibration at corners, especially if feed rate changes suddenly.
It causes higher wear on guide wheels, bearings, and tension rollers.
In thin or soft materials, high tension may cause wire deflection into the workpiece, overcutting internal shapes.
Spark instability can occur if the gap becomes too narrow due to wire bowing.
