Multi-wire Annealing Process

The annealing process with a Joule Effect annealer is critical because the annealing path must ensure the integrity of the wire surface, the absence of oxidation on the wire surface, the requested physical properties (mechanical strength, elongation, conductivity and resistance) and maintain the diameter and roundness of the wire. Wire quality and production efficiency are also influenced by contact ring surfaces.

To satisfy these requirements, the multiwire annealer must include a number of technical features, such as protective atmosphere in the preheating path, multimotor technology, adjustable pre-heating length, a wire walker before contact rings and cleaning devices on contact rings (see Photo 4).

New technology for Al wire drawing
Photo 4: Multimotor annealer for aluminium wire

A traditional Joule effect annealer is a machine with one motor and a belt transmission that connects all contact rings with a fixed ratio between each axis. This ratio is a compromise for the whole wire range diameter of the annealer and it is not possible to set an optimized adjustment for each wire diameter. This characteristic causes surface damage, reduces contact ring life and increases production costs.

In a multimotor annealer (see Photo 5), it is possible to optimize the kinematic ratio between each axis for each production recipe (wire diameter, alloy type etc.) stored in the HMI panel.

New technology for Al wire drawing
Photo 5: Rear view of a multimotor annealer

The mechanical and electrical characteristics of annealed aluminium wire are strongly influenced by the annealing voltage and current, therefore it is crucial for the electrical equipment to ensure stable values with low ripple and low THD-I.

Summary and future areas of development

We have described the latest developments for aluminium multiwire drawing and in-line annealing platform, designed to meet the latest market requirements, such as a larger range diameter for the outlet wire, an increased number of wires, a smaller outlet diameter of each wire, and a faster and more flexible production.

New electronic technologies, as well as innovative and improved design in multiwire drawing and annealing, generate savings through increased production efficiency (i.e. less wire breakage), longer life span of annealer contact bands, less energy consumption and a better wire quality surface.

The aim of the company is and will always be to supply technologically advanced systems that guarantee the lowest possible operating costs. Innovation and know-how will therefore form the basis for all future development activities over the next few years.

References
[1] Sampsistemi Technical Presentation, Aluminium Wire and Cable Conference 2015, Frankfurt.
[2] Sampsistemi Technical Presentation, 7th CabWire World Technical Conference 2015, Düsseldorf.
[3] 5th and 6th CabWire World Technical Conference, Düsseldorf 2011 and Milan 2013.
[4] Gaertner, M., “Aluminum Technology – The Wiring Harness of the Future Next Generation Terminals for Aluminum Wire Application,” SAE Technical Paper 2015-01-0245, 2015, doi:10.4271/2015-01-0245.