US Synthetic Bearings Site

Geometry

There are four primary parts to the geometry of a wire drawing die. Each one serves an essential role in successfully drawing wire.

• Entrance/Bell – The wide opening at the top of the die facilitates lubricant entering the die with the wire. More lubricant reduces the friction and wear on the die. Typically this angle is between 60 - 90º.


• Reduction Angle – The reduction is where the work is taking place in the die. The metal is plastically deformed as it is pulled through the tapered hole. The reduction angle is critical to the performance of the die and changes based on the material drawn. Typical angles range from 8 - 16º. Bunching/stranding dies will have a 24º angle.


• Bearing – The primary purpose of the bearing is to leave the wire at the finish size. The bearing length (typically expressed as a percentage of the diameter) is typically 25 - 50% of the diameter of the hole. A short bearing has less friction, while a long bearing tends to hold diameter longer.


• Exit/Back Relief – The polished back relief ensures that the wire comes out of the die with as little scuffing as possible. A well-polished surface will reduce fines and shaving. The exit taper ranges from 18 - 60º. This feature allows a smooth transition as the wire exits the die.

Typical Geometries

Area of Reduction

The area of reduction is determined by:

• Type of material being drawn
• Final application of that material
• Type of machine being used
• Desired elongation

Download Area of Reduction Calculator